Gabrian Blog – Gabrian https://www.gabrian.com Gabrian site Wed, 14 Dec 2022 01:19:25 +0000 en-US hourly 1 https://www.gabrian.com/wp-content/uploads/2019/07/cropped-image002-32x32.jpg Gabrian Blog – Gabrian https://www.gabrian.com 32 32 What is Alodine Finish, and How Does it Compare to Anodizing? https://www.gabrian.com/what-is-alodine-finish-vs-anodizing/ https://www.gabrian.com/what-is-alodine-finish-vs-anodizing/#respond Mon, 05 Dec 2022 09:59:48 +0000 https://www.gabrian.com/?p=25057 Aluminum is naturally corrosion-resistant, but when that’s not enough, designers will need to choose a protective aluminum surface finish. Alodining is a popular finishing option for preventing corrosion while still allowing electrical conductivity through the aluminum. This is part of what makes an alodine finish so useful in applications like parts for the electronics industry. […]

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Aluminum is naturally corrosion-resistant, but when that’s not enough, designers will need to choose a protective aluminum surface finish. Alodining is a popular finishing option for preventing corrosion while still allowing electrical conductivity through the aluminum. This is part of what makes an alodine finish so useful in applications like parts for the electronics industry.

It’s easy to get confused about what alodining means though. Especially with so many different names for the same process! This article explores what alodining means, the qualities of an alodine finish, and how it compares with another popular finishing option, anodizing.

What is an Alodine Finish?

An alodine finish is a type of conversion coating for aluminum parts that creates a thin protective film on the metal. This prevents corrosion and can be used as a primer for subsequent painting.

It should be noted that the Alodine® product is actually a registered trademark of Henkel, Inc., and there are other companies that offer similar products, like Iridite 14-2®. Due to its long-standing popularity, the term “alodine coating” is often used interchangeably with terms like chromate conversion coating and chem film in the aluminum manufacturing industry. In fact, Henkel has actually replaced alodine with Bonderite®, but the terms “alodine” and “alodining” have stuck.

While there are a number of accepted standards for applying alodine coatings on aluminum, MIL-DTL-5541 by the U.S. Department of Defense is easily the most widely recognized. The original version of this process used hexavalent chromium compounds, but these have since been found to be highly toxic and carcinogenic. Nowadays the majority of chemical conversion coatings on aluminum are completed using the Type II composition, which is free from hexavalent chromium.

How Does Alodining Work?

Clear alodined aluminum extrusions

Alodining is normally completed using a series of tanks for dipping, rinsing, and treating the aluminum parts (though spraying is also an option). The key step of the alodining process however is done by submerging the aluminum part in a carefully controlled chemical bath and holding it there while the alodine film forms on the aluminum surface.

Once the film has formed, it acts as a passivating barrier between the aluminum and corrosive agents. This prevents corrosion of any aluminum surfaces with chem film over them. However, an alodine finish is not very wear resistant, so corrosion can attack exposed aluminum surfaces if the chem film is scratched or worn away.

While the chem film is not conductive itself, the alodine layer is thin enough to allow electrical conduction through the barrier. This makes alodining a great corrosion prevention solution for applications that require electrically conductive aluminum parts.

Alodined vs Anodized Aluminum Parts

Alodined vs. anodized aluminum

Alodining and anodizing are often confused with one another on account of their similar-sounding names. But while alodining is a strictly chemical application process, anodizing is an electrochemical process for enhancing the natural passivating layer on the aluminum parts. Anodized aluminum must be submerged in a chemical bath with a carefully applied electrical current.

Aside from being different processes, aluminum product designers trying to choose a surface finishing process should be aware of the performance differences between these two solutions:

  • Protection from mechanical damage – Anodizing creates a ceramic-like layer that is much more wear resistant than chem film.
  • Design clearance considerations – Alodining creates a film less than 1 micron thick, while Type II anodized layers are between 1.8 and 25 microns. This may impact designs with incredibly tight tolerance requirements for finished parts.
  • Electrical conductivity – The ceramic properties of an anodized aluminum surface make it a poor conductor of electricity compared to an alodine finish.
  • Coloring parts – The porous aluminum oxide layer of anodized aluminum can be dyed a wide range of colors. Alodined aluminum however is either clear or gold/brown, so paint would need to be applied to achieve other colors.
  • Cost and technical expertise – An alodine finish is typically easier to perform and less costly than anodizing, which requires more technical experience to perform correctly.
  • Safety & sustainability – Type I alodining has the potential for severe health and environmental consequences. Type II alodining and anodizing are more comparable in terms of environmental impact, but if sustainability is a concern, powder coating aluminum may be worth considering.

Finishing Your Aluminum Parts

Man powder coating aluminum parts

Overall, there is not a one-size-fits-all solution to coating aluminum products. Alodining is popular in applications like fixed enclosures and cases for the electronics industry because it prevents corrosion, allows for easy electrical grounding, and is relatively cost effective. However, if an aluminum part will be exposed to scratching, impacts, or other mechanical forces, one of the more durable aluminum surface finishes is probably a better option.

For product designers seeking more tips, tricks, and guidance on working with aluminum extrusions, download Gabrian’s Aluminum Extrusion Design Guide.

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What is Mill Finish Aluminum, and How Does it Compare to Other Options? https://www.gabrian.com/what-is-mill-finish-aluminum/ https://www.gabrian.com/what-is-mill-finish-aluminum/#respond Fri, 28 Oct 2022 10:00:51 +0000 https://www.gabrian.com/?p=24852 As an engineer, material selection is one of the most important considerations when designing a new product or system. There are many different materials to choose from, and aluminum is an increasingly popular choice for many applications, from building construction and automobile manufacturing to electronics and aerospace design. Many different aluminum grades are available, ensuring […]

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As an engineer, material selection is one of the most important considerations when designing a new product or system. There are many different materials to choose from, and aluminum is an increasingly popular choice for many applications, from building construction and automobile manufacturing to electronics and aerospace design.

Many different aluminum grades are available, ensuring that you can find the one with properties that best suit your particular needs. Moreover, various aluminum finishing options can help improve the appearance and performance of an aluminum product, as well as protect it from corrosive elements.

When developing aluminum parts, engineers have access to a variety of commonly used choices such as mill finish, anodized, powder-coated, and painted aluminum. Here, we talk about what mill finish aluminum is, its characteristics, and how those characteristics can be further refined.

What is Mill Finish Aluminum?

Cut mill finish aluminum tube

Mill finish aluminum refers to the original, unpolished state of the metal that has not been treated or finished in any way. This form of the metal is largely untouched, with the surface often appearing somewhat dull. Mill finish aluminum has not undergone any further processing after being produced from raw aluminum through an extrusion process.

Because of this, mill finish aluminum retains many of the characteristics and properties of cast aluminum as well as soft spots on its surface. Its natural appearance can vary depending on the exact alloy used in its production and its intended usage.

Overall, it is typically characterized by flat and even surfaces that may show white oxidation spots as well as die and tooling marks. Mill finish aluminum can be an acceptable choice for those who are looking for a durable yet affordable metal. However, it will not last as long as products that have gone through surface finishing processes such as anodizing or powder coating.

Characteristics of Mill Finish Aluminum

A closeup of mill finish aluminum extrusions in a manufacturing facility

Even without finishing, aluminum has natural corrosion resistance due to its protective oxide layer. However, it will not have the same level of corrosion protection as anodized or powder coated parts. On long overseas shipments, white, powdery oxidation spots are likely to develop. As such, it is essential to take extra care with packaging to avoid metal exposure, and use desiccants to absorb moisture.

In addition, the aluminum’s electrical conductivity is better with a mill finish than it would be when anodized or powder coated — these finishes act as insulators. However, mill finish aluminum offers less thermal conductivity than anodized aluminum, making it less useful for heat dissipation applications.

Mill finish aluminum is relatively inexpensive compared to finished aluminum making it an economical choice for projects that don’t require the benefits offered by surface finishing. Ultimately, the unique blend of affordability and durability makes mill finish aluminum a potential option for any application that requires rugged material.

Some Popular Surface Finishes

When it comes to mill finish aluminum, there are many different surface finishes that can be used to enhance its appearance and performance.

Anodizing

Anodized aluminum building materials

One popular option is anodizing, a process that adds a protective layer of oxide to the surface of the aluminum. This process not only helps prevent corrosion but also produces eye-catching colors and textures that can help set your product apart from the competition. It also enhances metal’s heat dissipation properties. As such, anodized aluminum heat sinks are a common sight in the electronics industry.

Learn more about anodized aluminum.

Powder Coating

Powder coating of metal parts

Another option is powder coating, which involves coating the aluminum with a fine layer of pigment using an electrical charge. This form of finishing creates a smooth and durable surface that is both weatherproof and easy to maintain. Whether you’re looking for added protection or simply want to make your product more visually appealing, powder coating can be a great option.

Learn more about aluminum powder coating.

Liquid Paint

Painting metal products with spray gun

Designers often wonder, “Can you paint mill finish aluminum?” Yes, you can paint mill finished aluminum.

While this type of surface won’t hinder the performance or durability of the paint, it can make it challenging to achieve a perfectly even coat. Fortunately, there are a variety of methods that you can use to prep and paint mill finish aluminum effectively.

Some popular approaches include sanding down the surface, applying a primer or etching solution first, and using chemical bonding agents to ensure greater adhesion between the metal and the paint.

Learn more about painting extruded aluminum.

Is Mill Finish Aluminum Right for You?

Mill finish aluminum extrusions

It is essential to carefully consider all aspects of your project before deciding whether or not mill finish aluminum is right for you.

Aside from the anodizing, powder coating, and painting, there are other aluminum finishes to consider — so be sure to research all your options. Ultimately, the choice will depend on your specific requirements and expectations for your end application.

So if you’re looking for help with your aluminum extrusion designs, be sure to check out our Aluminum Extrusion Design Guide – it’s packed with essential tips for creating perfectly engineered profiles that optimize all aspects of production!

By following the tips included in our Design Guide, you can maximize quality and production speed while also reducing your costs. Whether you’re a first-time designer or an experienced professional, this guide will help ensure that your extrusion process is smooth and efficient.

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9 Types of Aluminum Finishes That Will Enhance Your Product https://www.gabrian.com/types-of-aluminum-finishes/ https://www.gabrian.com/types-of-aluminum-finishes/#respond Sun, 18 Sep 2022 10:43:24 +0000 https://www.gabrian.com/?p=24530 The excellent properties of aluminum make it a regular choice for extrusion designers in a wide range of industries. It has a fantastic strength-to-weight ratio, good corrosion resistance, good thermal and electrical conductivity, and more. While this may be enough for some applications, designers will frequently include additional finishing steps during production. Why is this? […]

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The excellent properties of aluminum make it a regular choice for extrusion designers in a wide range of industries. It has a fantastic strength-to-weight ratio, good corrosion resistance, good thermal and electrical conductivity, and more. While this may be enough for some applications, designers will frequently include additional finishing steps during production.

Why is this? Simply put, the right surface finish can elevate products from “good” to “outstanding!” Surface finishes can improve corrosion resistance, wear resistance, and aesthetic appearance to make extrusions last longer and look better.

Keep reading to learn what finishing options are available for your custom aluminum extrusions and what makes each unique. Many of these finishes can also be applied to die cast, rolled, or machined aluminum products.

#1 – Mill Finish

Mill finish aluminum extruded square tubes

At first, all aluminum extrusions have a mill finish. This reflects the state of the aluminum after it leaves the extrusion die. Die and tooling marks, a dull appearance, oxidation, and white “rust” can all be present on the aluminum after extrusion.

Generally speaking, a mill finish is only suitable for products that need to be made as cheaply as possible, where appearance doesn’t matter and they are only expected to last a short amount of time. Otherwise, you should at least consider one of the other aluminum finish options.

#2 – Anodizing

CNC machined parts color anodized

Anodizing is commonly used to improve the corrosion resistance and wear resistance of aluminum parts. It can also provide other desirable benefits, like improved heat dissipation and the ability to accept dyes.

Unlike paints and coatings, anodizing does not apply an external product to the exterior of the aluminum. Instead, an electrochemical process is used to stimulate the naturally-occurring layer of aluminum oxide into growing thicker. This protects the underlying aluminum from its environment, and can even accept dyes. However, the color possibilities for anodizing are not as abundant as in powder coating.

#3 – Powder Coating

Yellow powder coated metal product

For bright, long-lasting colors with high UV resistance, many product designers will choose powder coating. For this process, aluminum extrusions are cleaned and prepped, then sprayed using an electrostatic gun to apply dry paint powder to the aluminum surface. After this, the powder-coated aluminum extrusions are baked to melt and cure the coating into an even finish.

Powder coatings are not as hard and durable as anodized aluminum, but they provide an exceptional appearance and great corrosion resistance as long as the coating remains intact. The powder coating process is also considered more environmentally friendly than liquid painting, which uses solvents containing volatile organic compounds (VOCs).

#4 – PVDF Coating

Building with PVDF coated aluminum panels

Polyvinylidene fluoride (PVDF) coatings are resin-based coatings that often have embedded color pigment particles. They must be applied to extrusions in a factory setting and can be used to create a wide variety of matte-finish colors.

PVDF coatings are highly corrosion resistant, highly resistant to fading, and chemically resistant, making them excellent for exterior applications like aluminum wall cladding. They also don’t require an oven for curing and can be applied in a thinner layer than powder coatings. Finally, while it can be considered slightly more wasteful than powder coating, this aluminum coating does not contain any harmful VOCs.

#5 – Other Liquid Paints

Painting metal products with spray gun

While PVDF is technically a liquid paint, it is a somewhat distinct process from other liquid paints. Liquid paints are an enticing option when you need a very particular color, especially for small batches. That’s because liquid paints offer the widest selection of color possibilities, and paint can be mixed up in the quantities needed for the products in question.

Unfortunately, the solvents used in these types of paints contain harmful VOCs that are bad for both people and the environment. Painters need to use VOC abatement systems to mitigate the risks associated with these types of aluminum surface finishes.

#6 – Mechanical Finishing

Die cast parts shot blasted

Rather than one type of process, mechanical finishes encompass an assortment of methods used to affect the surface of aluminum extrusions. Common examples include abrasive blasting, grinding, and polishing.

Instead of applying chemicals, mechanical force is applied using abrasive media to smooth the aluminum’s surface. This can improve its appearance or prepare it for another finishing process.

#7 – Sublimation

Aluminum window frame with wood look finish

Commonly seen in more artistic applications, sublimation is a process for creating colored patterns on aluminum. The patterns are transferred from a film wrapping onto the aluminum surface using heat.

A popular choice for sublimation in extruded aluminum is to create a wood pattern. This allows designers to have more flexibility in the products they create. Like creating outdoor furniture or window frames with a wooden appearance that has improved durability and lighter weight from the aluminum.

#8 – Alodining

Alodine finished extrusions

A cheaper alternative to anodizing, Alodine coatings can be used to enhance the passivating oxide layer on the surface of aluminum extrusions, improving corrosion resistance. While the Alodine chem film is not as strong or wear resistant as anodized aluminum, it has a high electrical conductivity that may be necessary for some applications.

It should be noted however that the Alodine solution is not as environmentally sustainable as other options on this list.

#9 – Bright Dipping

Tubes with a specular (mirror) finish

Finally, bright dipping is a process for creating a brilliantly shiny surface finish on your aluminum extrusions. By bathing them in acid, the microscopic fluctuations in the surface of the extruded aluminum are smoothed to create a “mirror-like” finish.

While it may be required to create certain products, bright dipping is a potentially dangerous and environmentally unsafe process. It also only works well with certain grades of aluminum, namely 6463.

Summary

Overall, aluminum surface finishes are a great idea to get more out of your product. While mill finish aluminum will cost less upfront, any applications where corrosion and wear are a concern will often need more frequent replacement of unprotected aluminum products. This means money savings over the long run.

Surface finishing extruded aluminum is also important if visual appeal is important to your design. Depending on your needs, you can even combine different processes to get the benefits of both.

To learn more about aluminum finishes, joining, and other important considerations for aluminum extrusions, download our Aluminum Extrusion Design Guide.

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Aluminum Extrusion Alloys: Which One Should You Choose for Your Project? https://www.gabrian.com/aluminum-extrusion-alloys/ https://www.gabrian.com/aluminum-extrusion-alloys/#respond Fri, 15 Jul 2022 12:07:03 +0000 https://www.gabrian.com/?p=23637 There’s a lot to consider during the aluminum extrusion design process, from the desired profile shape to procurement costs and even options for special surface finishing. But one of the first considerations is typically deciding which aluminum alloy is the best for the project. Using aluminum means a great assortment of physical characteristics, including a […]

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There’s a lot to consider during the aluminum extrusion design process, from the desired profile shape to procurement costs and even options for special surface finishing. But one of the first considerations is typically deciding which aluminum alloy is the best for the project.

Using aluminum means a great assortment of physical characteristics, including a high strength-to-weight ratio, good corrosion resistance, and an appealing surface finish. Product designers can further emphasize particular qualities by choosing the aluminum alloy that best fits their application.

This article will highlight the material properties you must evaluate when selecting an aluminum extrusion alloy. It will also suggest a few common aluminum alloys that you should consider for your product.

Extrudability of Wrought Aluminum Alloys

Aluminium extrusion production line at factory

“Pure” aluminum is extremely ductile, and you can easily form it into a wide variety of shapes, including by extrusion. By adding different alloying elements, such as magnesium, zinc, or copper, you can refine “pure” aluminum into a series of different wrought aluminum/aluminum extrusion grades.

While introducing these alloying elements reduces aluminum’s exceptional formability, it also improves other desirable properties. As such, unless the project is for something like aluminum food trays, product designers typically prefer to have alloyed aluminum over commercially pure aluminum for other added benefits.

From improved strength to better weldability, alloying hones the characteristics of aluminum to suit the end product better.

Wrought Aluminum Alloys for Extrusion

Aluminum ingots

When it comes to extrusion, one of the key aspects that sets aluminum apart from other metals is its formability. But as noted by Volume 14A of the ASM Handbook, a stronger aluminum alloy with a higher concentration of alloying elements is generally more difficult to extrude and has a lower extrusion rate.

While 1XXX-series aluminum alloys have the best formability, this doesn’t mean other alloys cannot be extruded. Typically, alloys from the 3XXX, 4XXX, and 5XXX series still feature excellent formability alongside other improved characteristics.

Extrusion is more challenging for wrought aluminum alloys from the 2XXX, 6XXX, and especially the 7XXX series, but this does not prevent them from being made into excellent extruded products. With special care by an experienced extrusion supplier, these alloys can offer product designers either exceptional strength or an outstanding balance of overall properties.

The additional challenge of extruding these alloys generally comes with a higher price tag, but it is well worth it for many applications.

Main Properties for Different Aluminum Alloy Series

Aluminum extrusion alloys: billets for extrusion process

Determining which aluminum alloy to use will depend on the designer’s needs and the product’s intended application. As a starting point, designers may want to ask themselves which of the following qualities are vital for their product, which are nice to have, and which, if any, are not relevant:

  • Strength
  • Formability
  • Corrosion Resistance
  • Heat Treatability
  • Weldability
  • Machinability

Based on the requirements for each of those properties, designers can evaluate the different wrought aluminum alloy series to see which ones best align with their needs. Typically, this will lead them to select an alloy from the 2XXX, 3XXX, 5XXX, 6XXX, or 7XXX series.

Series Strength Formability Corrosion Resistance Heat Treatable? Weldability Machinability
2XXX Very High Poor Poor Yes Poor Good
3XXX Medium Very Good Good No Very Good Good
5XXX High Very Good Very Good No Very Good Moderate
6XXX High Good Good Yes Very Good Good
7XXX Very High Poor Poor Yes Poor Moderate

When an application requires a very high strength-to-weight ratio, designers are most likely to review aluminum alloys from the 2XXX or 7XXX series for a solution. When corrosion is the primary concern, 5XXX-series alloys should be strongly considered. Aluminum alloys from the 6XXX-series are one of the most popular choices for their great combination of properties.

For specific applications, designers may also want to consider thermal properties, electrical conductivity, hardness, surface finish, or other specific properties not listed above. These tend to be more niche, but could still be necessary for products such as heat sinks or electrical wiring.

The Best Aluminum Extrusion Alloys

Crane beam moves stack of aluminum profiles in a factory warehouse. Heavy metallurgical industrial products, manufacturing business production concept

Knowing the characteristics of the different wrought aluminum alloy series listed previously, extrusion product designers have better insight into which alloys might be worth investigating further. The properties of each alloy in a series fall within a particular range, with individual alloys gravitating to different ends of the range depending on their specific composition and any temper treatments.

A handful of the best aluminum alloys for extrusion are listed below along with some of their properties and ideal applications.

Alloy Tensile Strength1 Strengths Weaknesses Applications
2024 455 – 483 MPa Great strength, good formability Poor corrosion resistance, poor weldability High strength structural applications, aircraft fuselage and wings, gears and shafts, cylinders and pistons
3003 110 – 200 MPa Great formability, good corrosion resistance Low strength, average machinability Fuel tanks and piping, chemical equipment, heat exchangers, truck and trailer parts, cabinets
5052 193 – 290 MPa Great formability, great corrosion resistance Poor machinability Pressure vessels, marine equipment, fencing, hydraulic tubes, appliances
6005 170 – 270 MPa Great weldability, good corrosion resistance Average formability, average machinability Furniture, railroad cars, ladders, seamless tubing, safety railings
6061 241 – 310 MPa Great weldability, good machinability, good corrosion resistance Average formability Building products, automotive parts, piping, furniture, bicycle frames, railroad cars
6063 186 – 290 MPa Great weldability, good formability, good corrosion resistance Average machinability Window and door frames, safety railing, outdoor furniture, electrical and electronics parts, piping, storage tanks, sports equipment
7075 228 – 572 MPa Great strength Poor formability, poor weldability Aircraft wings and fuselages, missile parts, gears and shafts, worm gears

1Tensile strength varies depending on temper treatment.

Which Alloy Should You Choose?

Aluminum frame made from aluminum extrusion alloys

As we’ve said early in the article, the best alloy for your product ultimately comes down to the intended application. For exceptional strength, you can use aluminum alloys 2024 and 7075 for their high strength-to-weight ratio. If, on the other hand, you want a versatile alloy that performs well under a wide range of circumstances, 6061 or 6063 may have what you need.

These alloys are not a comprehensive list, and other factors might influence the suitability of an alloy. If mild atmospheric corrosion is a concern, you may not necessarily need to choose a highly corrosion-resistant alloy like 5052. Instead, you could use a secondary process like anodizing or powder coating to improve the durability and aesthetics of a different alloy that better suits other design parameters.

For more insight into how to design for aluminum extrusions, take a look at Gabrian’s Aluminum Extrusion Design Guide.

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Aluminum Extrusion Bending: An Overview for Design Engineers https://www.gabrian.com/aluminum-extrusion-bending/ https://www.gabrian.com/aluminum-extrusion-bending/#respond Thu, 23 Jun 2022 22:25:35 +0000 https://www.gabrian.com/?p=23380 From rails for industrial equipment to automotive applications to bold artistic sculptures and architectural designs, there are plenty of reasons you may want to create curved aluminum extrusions. While the ductility of aluminum makes it well-suited to bending for these applications, you must address several challenges to ensure your final product meets quality specifications. This […]

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From rails for industrial equipment to automotive applications to bold artistic sculptures and architectural designs, there are plenty of reasons you may want to create curved aluminum extrusions.

While the ductility of aluminum makes it well-suited to bending for these applications, you must address several challenges to ensure your final product meets quality specifications. This decision-making process ultimately comes down to managing stresses during bending.

Bending aluminum extrusions imparts immense stress onto the workpiece. The extrusion can experience tension, compression, and torsion all at once. The results can range from minor thinning and swelling of profile segments to unacceptable defects like deformed profiles, buckling, or cracking.

This article explains some of the best practices extrusion designers can apply to ensure good bendability in their products, along with six popular methods for bending aluminum extrusions.

Design Considerations for Aluminum Extrusion Bending

Best Aluminum Alloys for Bending

Designers that want to bend aluminum extrusions have a lot to consider. While some bending methods can achieve a tighter bend radius and others can better ensure profile stability, a few key considerations can help you improve your product’s bendability for any bending method.

Choice of Material

First, the material you choose has a major impact on bendability. As we’ve discussed in previous articles, some alloys are better suited to bending than others. While not the easiest to bend, alloys from the 6XXX series tend to see widespread application thanks to their exceptional combination of properties.

Bending Before Temper Treatment

The physical properties of an alloy can also be improved using temper treatments, but applying them before bending can make bending an aluminum extrusion more difficult and more expensive to produce. The simple workaround is to conduct the full or partial temper treatment after bending so that your product is cheaper to produce and better meets specifications.

Profile Design Choices

Other considerations for improving the quality of curved aluminum extrusions and lowering production costs can include:

  • Improving profile geometry,
  • Designing uniform wall thickness, and
  • Minimizing the profile size when possible.

Especially with profile shape, poor design can lead to distortion of the profile and cracking during bending. Rounded corners, profile symmetry, and good internal supports can all help improve stability during bending.

Perform Surface Finishing Operations After Bending

Man painting aluminum products with a spray gun

Finally, if an extrusion bend design requires surface finishing, such as anodizing, or other secondary operations, it may be best to perform these operations after bending. While some surface finishes, like powder coating, may be capable of tolerating limited bending, there is always a risk that the bending process damages the surface.

While applying the considerations above can improve bendability and lower cost, they may not be possible depending on the restrictions of the design. Luckily, you still have options. If you have a difficult-to-bend aluminum extrusion, you can consult an experienced bending specialist to determine what additional measures you can take to meet your bending needs or if special equipment is needed.

How to Bend Extruded Aluminum: 6 Methods

There are several common ways to bend extruded aluminum which can be categorized into six main methods.

1) Roller Bending

Three-Roller Bending Example for Aluminum Tube

As one of the most widely used methods for bending long aluminum extrusions, three-roller bending offers minimal tooling costs for common profiles and can roll fully circular components. While a key benefit of roller bending is that you can bend the entire extrusion length instead of only a single segment at a time, rolling for tighter bends may need to be done in increments to reduce the bend radius down to the desired curvature gradually.

The consequences of this stepwise rolling can include lower precision than other methods and poor scalability. These restrictions typically make roller bending better suited to low-to-medium size production runs and ideal for prototyping.

2) Ram Bending

Also known as push bending, this method is sometimes considered the simplest and least expensive approach, making it comparable to compression bending. While it can reliably bend extrusions to precise angles, ram bending is more likely than most other methods to deform the profile in undesirable ways and can only bend one portion at a time.

3) Rotary Draw Bending

Aluminum tube bender

Image Source: Kolb-Rahmenbau.ch on Flickr

Rotary draw bending involves clamping an extrusion and pulling it around a rotating bending die. While capable of bending to exceptionally precise angles, rotary draw bending can only bend a single segment at a time.

Rotary draw bending also boasts the ability to handle larger-sized extrusion profiles and multiple, close-proximity bends in a single part. It is an ideal method for custom bending profiles on round tubing, which can be supported by an internal mandrel to provide extra support for the profile during the bending.

4) Compression Bending

CNC 3D Pipe Bending Machine

While the basic setup looks similar to rotary draw bending, the process is less complicated. Instead of a rotating die pulling the extrusion around its perimeter, compression bending uses a compression die to wrap the extrusion around the fixed bending die.

Like rotary draw bending, you can bend only one section at a time and make multiple bends in any direction. However, this method offers the aluminum profile much less support and can easily result in deformation. The main advantage of compression bending is for high production volumes as it is fast and cost-effective to complete each bend.

5) Stretch Bending

Sometimes called tensile bending, stretch bending can be one of the more expensive bending solutions thanks to bending die costs, but it offers unique benefits. The bending specialist can achieve the desired bending shape with minimal distortion or surface damage by placing the workpiece in constant tension during bending.

While limited to larger bend radii, the bending die for this specialty method can achieve a range of dynamic shapes on very large workpieces. Larger production volumes using the same profile can help offset the cost impact of a stretch bending die.

6) Free-Form Bending

As one of the most advanced methods on this list, CNC free-form bending feeds the aluminum extrusion through an articulating ceramic die to form a wide range of complex custom bends. While most common for round tubing, this technique can form other extrusion profiles into unique products. This technology is less common than the other bending methods but may see significant potential in the near future.

Which Method is Best for Your Product?

Curved aluminum T-slot profiles

Each bending method has unique advantages that make it better suited to specific applications. While ram bending and compression bending offer low-cost options for bending aluminum extrusions, they can negatively impact aesthetics and sturdiness. On the other hand, stretch bending and rotary draw bending can produce high quality, high precision bends, but at higher costs and with other potential drawbacks.

Overall, even with the best bending method for your product, consistently meeting quality requirements for challenging extrusion profiles may prove extremely difficult. To help with this, consult our Extrusion Design Guide or speak with a Gabrian service professional to get expert insight into designing and bending extruded aluminum products.

Get the best value out of your next aluminum extrusion project by partnering with Gabrian. Our Custom Aluminum Extrusion Services will help you meet your project requirements while keeping production costs low.

 

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10 Effective Ways of Joining Aluminum Extrusions: A Guide for Product Designers https://www.gabrian.com/joining-aluminum-extrusions/ https://www.gabrian.com/joining-aluminum-extrusions/#respond Sat, 11 Jun 2022 01:40:51 +0000 https://www.gabrian.com/?p=23195 Extruding aluminum offers the ability to create a wide array of profiles to meet your needs, ranging from simple to complex. While experienced designers can incorporate a variety of features into a single extruded profile, it may not be possible or practical to achieve all that you need with a single extrusion. This is where […]

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Extruding aluminum offers the ability to create a wide array of profiles to meet your needs, ranging from simple to complex. While experienced designers can incorporate a variety of features into a single extruded profile, it may not be possible or practical to achieve all that you need with a single extrusion. This is where joining techniques come into play.

When trying to minimize die and tooling costs, create modular designs, or accommodate specific applications, it may make more sense to design two or more smaller extrusion profiles that you can join together later. However, choosing the most cost-effective and efficient joining method can be overwhelming.

This article offers up various options for designing joined or interlocking aluminum extrusions. It also sheds light on how to choose a suitable joining method so you can better adapt your next design.

Common Joint Types for Aluminum Extrusions

The versatility of extruded aluminum gives designers access to a wide range of joints that they can apply to their products. Whether you need a permanent, semi-permanent, or non-permanent design, there are lots to choose from.

#1 – Flat Joints

These types of joints are distinct from all the other joints in this list as they are simply “butted” up against one another without any special mating surfaces. Whether you assemble them as a butt joint, lap joint, tee joint, or another arrangement, these joints need to be held together by something other than geometry, such as welding or fasteners.

Tee Joint - Butt Joint - Edge Joint - Lap Joint

Figure 1: Flat joints

 

#2 – Nesting Joints

With specially designed mating surfaces, these joints are a bridge between flat joints and more complex mating geometries. Their shape allows for easy, precise alignment between parts, but, depending on the application, they may require more than just geometry to stay together, similar to flat joints. Common examples include tongue and groove joints and half-lap joints, which restrict movement in some directions without locking the components together.

You can make semi-permanent and permanent assemblies from nesting joints using either drilled holes with fasteners such as rivets, or bonding through an adhesive, weld, or other method.

Figure 2: Nesting joint (Tongue and groove joint)

Figure 2: Nesting joint (Tongue and groove joint)

 

#3 – Interlocking Joints

Interlocking joints are one of the simplest forms of geometry-based joints that don’t rely on fasteners or bonding for joining. Typically made by rotating two components into position, this joint can be sturdy and is quickly taken apart by counter-rotating components out of position. You can add additional elements to lock these joints into position and prevent accidental disassembly, similar to key-locked joints.

Figure 3: Interlocking joints

Figure 3: Interlocking joints

 

#4 – Slip-Fit Joints

Sometimes called sleeve joints, you assemble extrusions using slip-fit joints by sliding them together along their lengths. While this type of geometry-focused joint offers reliable strength, it can be cumbersome to assemble, particularly in small or congested spaces.

Figure 4: Slip-fit joints

Figure 4: Slip-fit joints

 

#5 – Snap-Fit Joints

Also known as snap-lock joints, the mating geometries of these joints are generally reserved for more permanent applications. By relying on aluminum’s relatively high ductility to bend without experiencing permanent deformation, snap-fit joints slide together into a locked position that is generally very difficult to take apart.

Figure 5: Snap-fit joints

Figure 5: Snap-fit joints

 

#6 – Nut Tracks

Unlike interlocking, slip-fit, and snap-fit joints, nut tracks rely on more than just geometry for sticking together. Extrusions with nut tracks include a channel designed to accommodate a hex-head nut or bolt so that you can fasten extrusions and other components together as needed. This design is highly modular and customizable, allowing for rapid assembly of custom frames and easy attachment of other add-ons.

T-slot and V-slot aluminum extrusions work similarly to nut tracks but require custom hardware based on their respective building standards.

Figure 6: Nut tracks

Figure 6: Nut tracks

 

#7 – Screw Ports

Whether you are adding a protective cover to the end of an extruded segment or affixing a perpendicular component, you may want to consider adding screw ports. Adding a screw boss to an extruded profile is a simple, sturdy way to facilitate adding components to the end of your extrusion.

Figure 7: Screw ports

Figure 7: Screw ports

 

#8 – End Joints

End joints are similar to joints that take advantage of screw ports, adding special channels that allow you to create joints at the ends of extrusions. Unlike screw ports, which allow for the attachment of other components to the extrusion, end-joints let you seamlessly connect extrusions end-to-end. By using an insert such as a coupling or cleat, end joints can either extend extrusions in the same direction or create sturdy corner joints.

Figure 8: End joints

Figure 8: End joints

 

#9 – Hinge Joints

Whether permanent or non-permanent, most of the joints on this list are designed for fixed applications. Hinge joints are the exception. They are meant to allow for limited rotational movement while still keeping the extrusions aligned.

Figure 9: Hinge Joints

Figure 9: Hinge Joints

 

#10 – Key-Locked Joints

Key-locked joints are geometry-based extrusions that take advantage of two or more primary extrusions alongside a key to create a stable joint. While the primary extrusions will not lock together on their own, the addition of a key prevents them from coming apart. You must insert the key laterally similar to slip-fit joints, but depending on the application, it may not need to run the length of the entire extrusion.

Figure 10: Key-locked joints

Figure 10: Key-locked joints

 

Bonus – Combination Joints

While not necessarily a joint on its own, capable extrusion designers can take advantage of multiple joint types to create combination joints. Depending on the intended application for the product, combination joints can increase versatility and improve stability. For example, incorporating a hinge joint into an extrusion profile with a nut track would allow you to firmly attach components along the nut track while allowing rotation around the hinge axis.

How do You Choose the Right Joining Method?

Part of the reason aluminum extrusions are so popular is their versatility, which comes in part from the wide range of joining methods designers can choose from. However, choosing the best one for your application can be challenging.

To simplify this, you should think about the expected applications of your design. Does your design need to be disassembled and reassembled? Is easy field assembly necessary? What tools does the end-user have access to when assembling your products?

Joining Extrusions Permanently

Aluminum profiles welded into a frame

You can use welding, brazing, soldering, and adhesives to combine different extruded profiles permanently. These techniques can be applied either at the time of manufacturing or in the field during the final installation. However, once you use these methods, it is generally difficult to separate the components and reuse them for the same application.

Joining Methods That Offer Customizability

Various Pieces for T-Slot Aluminum Framing

Mechanical fasteners such as nuts, bolts, screws, and rivets offer a higher degree of versatility when joining aluminum extrusions and can often be taken apart and reassembled as needed. Mechanical fasteners offer customizability, making extrusions that use them the first choice for many customers.

Extrusions With Mating Geometries

Polyamide thermal break between two aluminum profiles

While you can apply these joining methods to a wide range of manufactured products, one method that is particularly well-suited to aluminum extrusions comes from mating geometries. When the profiles of two or more extrusions fit together, designers can create non-permanent, semi-permanent, or permanent assemblies to match the design application.

Similar to how seasoned woodworkers can create a whole array of sturdy joints depending on their needs, extrusion designers rely on several joint types to create a design that best fits the intended application of their product.

Which Joint Type is the Best?

Engineers discussing ways of joining aluminum extrusions

Unfortunately, there is not a one-size-fits-all solution to joining aluminum extrusions.

Each joining method and joint type has advantages and limitations that make it better suited to specific applications.

For example, suppose you want to create a highly modular assembly capable of integrating a wide range of add-ons. In that case, you’ll most likely want to consider joints that take advantage of fasteners and mating geometries.

However, this type of non-permanent design would not be suitable if you were concerned about thefts or tampering. Instead, you might prefer a permanent or semi-permanent solution that prevents easy disassembly, such as welding or snap-fit joints.

Gabrian offers a full range of Custom Aluminum Extrusion services so that we can manufacture the perfect extruded aluminum product for your needs. Learn more about the design of aluminum extrusions by consulting our Extrusion Design Guide or contacting our service experts.

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5 Important Factors That Impact the Cost of Custom Aluminum Extrusions https://www.gabrian.com/cost-of-custom-aluminum-extrusions/ https://www.gabrian.com/cost-of-custom-aluminum-extrusions/#respond Mon, 09 May 2022 23:05:29 +0000 https://www.gabrian.com/?p=22695 Ordering a custom aluminum extrusion can often be the right choice when there is nothing in regular inventory that meets your needs. Whether you need a specific profile, an unusual alloy, or a particular surface finish, knowing more about how much custom aluminum extrusions cost can help you better predict expenses and manage your project’s […]

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Ordering a custom aluminum extrusion can often be the right choice when there is nothing in regular inventory that meets your needs.

Whether you need a specific profile, an unusual alloy, or a particular surface finish, knowing more about how much custom aluminum extrusions cost can help you better predict expenses and manage your project’s budget.

In this article, we cover some of the common factors that impact the cost markup for custom extrusions so that you can better prepare for how these products will impact your budget.

#1 Die and Tooling Costs

Aluminum extrusion dies on a rack

For custom profiles, new dies have to be tailor-made from scratch. For the manufacturers that need to recoup the costs for these special dies, this means raising the overall price of your order.

Compounding this even more, particularly complex geometries for the new die design will take more time and labor to produce, further increasing the cost to produce and the lead time for the final product.

How Much are Die and Tooling Costs?

Tool costs for extrusion dies that are used in normal architectural and industrial applications can range from $400 to $1,000. Tool costs for large parts to be made on 2,000-4,000 ton presses could be as high as $2,000.

Sometimes our manufacturers refund tool costs if a stipulated amount is purchased within 2 years. Most manufacturers do not charge for replacement tools after their useful life if orders continue.

Normal tool turnaround time is 3-4 weeks and production follows within a week of sample approval.

Which Factors Increase Complexity and Die Cost?

  • The Circumscribing Circle Diameter (CCD): This refers to the smallest circle that encloses the entire cross-section of the extrusion. Designs with CCDs between 1 and 10 inches are less expensive than those over 10 inches. Additionally, presses capable of utilizing dies with very large CCDs are rare, limiting the number of manufacturers capable of doing this work and driving up the price further.
  • Die Symmetry: Symmetrical extrusion profiles are easier to manufacture, making them more cost-effective to produce than complex profiles. A symmetrical die allows for a uniform flow when the material passes through it, distributing the load evenly and preventing die fractures.
  • The Joining Method: Sometimes, if a profile requires a complex die, it makes sense to make two or more simple extrusion profiles with adequate joining mechanisms than to extrude the larger, more complicated profile in one go. Joining methods such as nut tracks, snap fits, interlocking, and T-slots are very common.

For more detail on these and other important design considerations, check out our helpful Aluminum Extrusion Design Guide as well as our article on Aluminum Extrusion Dies.

#2 Current Aluminum Cost

Aluminum billets stacked outside

As you might expect, the current cost of the base material used for your product will have a direct impact on the final cost of the order. The price of raw aluminum is affected by many factors, such as global demand, industry trends, and electricity costs. The base price of aluminum can be estimated through exchanges like the LME Aluminum valuation.

Since the cost of aluminum has fluctuated substantially in recent years, sometimes it makes sense to pay for a large amount of metal all at once to lock in a rate, particularly when you have ongoing production needs with a manufacturer.

In these cases, the extruder buys a considerable amount of the metal in advance and uses it for your production needs over time. By doing this, the extrusion costs can be made more predictable for you.

It’s also important to keep in mind that different aluminum grades may have different costs and that a manufacturer likely won’t be stocked up on many of the unusual aluminum alloys that are sometimes requested in custom orders. This can increase the price for obtaining special stock.

How Much Does Aluminum Cost?

The cost of aluminum is the biggest wild card in the whole equation of extrusion cost. It has varied anywhere from $1,500 to $3,500 per metric ton in recent years.

Material costs can be affected by political events in different parts of the world. For example, Ukraine and Russia are key aluminum producers, and the war between them affects prices. Also, China is a big smelter of Aluminium, and recent environmental restrictions impact their operations.

#3 Labor and Production Costs

Worker moving aluminum ingots

Of the different factors listed in this article, the cost of manufacturing labor is often one of the easiest to predict when evaluating the cost for custom aluminum extrusions. Relatively stable and based on regional conditions and regulations, this information is typically easy to find. While manufacturing abroad can incur an increase in shipping costs, these are typically offset by larger production volumes as we’ll discuss later on.

Additional production expenses that can impact overall costs include operating overhead, equipment purchases, maintenance, utilities, and more. While they may be somewhat harder to determine, they are similarly impacted by the conditions in the region where the manufacturing takes place.

#4 Surface Finishing and Secondary Operations

CNC machine for aluminum profiles

Surface finishing, as well as other secondary operations, can be performed on extrusions after concluding the extrusion procedure. These processes can be done to improve appearance, enhance protection, or to achieve special physical or mechanical characteristics needed for the product’s intended application.

Machining

When it comes to physical alterations, CNC machining can be used to create holes and shapes that cannot be achieved by extrusion alone. Bending extrusions is another common practice for creating physical alterations when a straight profile is not suitable for the intended application.

Temper Treatments

Temper treatments are the most common secondary operations used for changing the mechanical properties of extruded aluminum products. Temper treatments can be used to alter the strength, formability, hardness, and other physical attributes of extrusions. Normally, there is no extra charge for different tempers, though, as long as volumes are high enough.

Surface Finishes

Finally, surface finishes can be applied which affect only the aluminum’s surface. Aluminum extrusions naturally have a very smooth finish after normal processing, so they rarely require sanding, but sandblasting can be used to roughen up the surface if required, especially in preparation for other surface treatments like coatings.

Worker powder coating aluminum parts

Coatings and other types of surface finishes add a layer of material to the extruded aluminum for protection, improved appearance, or both. For example, powder coatings create a very durable and hard finish in a wide assortment of custom colors. Anodizing, on the other hand, is an electrochemical process that thickens the naturally-occurring oxide layer in aluminum to provide an appealing and corrosion-resistant surface. (Related: Should You Anodize or Powder Coat?)

If you want to learn more about these and other surface-finishing processes for aluminum extrusions, you can read our article on Types of Finishes for Aluminum Extrusions.

While adding any secondary operations to your product order will inevitably increase cost, you can save money by selecting a manufacturer with vertically integrated capabilities. Facilities that combine extrusion, fabrication, and finishing services will minimize the burden of logistical management and reduce the final cost for your order when compared with completing coordinated operations between multiple different vendors.

How Much Does Surface Finishing Cost?

Costs for anodizing and powder coating vary from $1,200 to $1,400 per metric ton depending on the profiles. Alodine finishing is a little less expensive at about $800 per metric ton. There are special finishes such as wood-look finishing that are significantly more expensive and the cost generally depends on surface profiles.

How Much Does Fabrication Cost?

Prices vary based on the complexity and kinds of machines required. Simple drilling operations can be in the range of $200-$300 per metric ton. For more complex operations, there will be tooling costs involved as well as machining time.

#5 Production Volumes

Packaged aluminum extrusions for shipping

As with many other manufactured items, buying custom aluminum extrusions in bulk can lead to lower costs per unit produced.

This is true in part because, when custom orders are being produced, the basic die and tooling costs will often be very similar between a small and large order. If the manufacturer needs to recoup this expense for a small number of parts, the cost to produce each part is higher and is passed on to the buyer. However, as the production volume increases, the cost-per-unit will go down.

Bonus Factor: Logistics Costs

Container ship sailing on the ocean

The COVID pandemic has put into perspective how much the low cost of commodities can be impacted by transportation logistics. For example, shipping disruptions have caused major fluctuations in the cost of containers shipped from India since the start of the pandemic. Around the world, the rising costs for containers and shipping ultimately impact the final price tag facing consumers, and these costs can change overnight.

Additionally, local duties and tariffs on imported products, such as the United States’ anti-dumping duty, can raise the cost of bringing products from abroad to your market. These extra fees may be harder to foresee or determine, but looking into whether they could impact your business can help you make adjustments that ensure your project remains profitable.

Despite these concerns, the shorter lead times in Asia compared to North America, as well as the lower production costs, are still worth it for many customers around the world.

How Much Does International Shipping Cost?

The cost of international shipping has varied widely in recent years. Shipping a 40-foot container from Asia to North America has ranged anywhere from $8,000 to as high as $20,000. The costs have been driven by political uncertainty as well as the economic and trade climate. Recently the pandemic has had a significant impact on container availability and the Russia-Ukraine war has added more uncertainty impacting cost and availability.

Optimizing the Cost of Custom Aluminum Extrusions

Accountant reviewing the cost of custom aluminum extrusions

Ultimately, the total price tag for manufacturing custom aluminum extrusions comes down to a combination of many factors. Some of these factors are predictable, like production volumes and labor costs, while others can be harder to foresee, like shipping costs and the market price of aluminum stock.

Gabrian’s Aluminum Extrusion Guide can help you to optimize the design of your extrusions so you can minimize production costs. If you need additional insights, our aluminum extrusion experts can help you decide the best combination of alloy, surface finish, and temper treatment needed to achieve your project’s goals at a cost you can manage.

Take advantage of our custom aluminum extrusion capabilities for your next manufacturing project to get a rapid turnaround for high-quality extrusions that fit within your budget.

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4 Secondary Operations to Consider for Aluminum Die Cast Parts https://www.gabrian.com/secondary-operations-for-aluminum-die-cast-parts/ https://www.gabrian.com/secondary-operations-for-aluminum-die-cast-parts/#respond Thu, 28 Apr 2022 23:53:08 +0000 https://www.gabrian.com/?p=22574 In previous articles, we’ve covered what happens before and during the casting process. Choosing the most suitable aluminum alloy, die design considerations, and carrying out die-casting operations are all vital stages of product development. In this article, we extend the discussion to talk about some other processes that can occur after removing the cast from […]

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In previous articles, we’ve covered what happens before and during the casting process. Choosing the most suitable aluminum alloy, die design considerations, and carrying out die-casting operations are all vital stages of product development.

In this article, we extend the discussion to talk about some other processes that can occur after removing the cast from the die. These processes are known as secondary operations or post-cast operations.

Why Do Some Die-Cast Parts Require Secondary Operations?

As-cast aluminium high pressure die cast parts for automotive and electrical equipment

The process of die-casting aluminum parts is renowned for its exceptional dimensional accuracy and smooth, even surface finish. Many die-cast parts are already very close to the final desired condition when removed from the die, needing only some flash trimming.

Nevertheless, some die-cast products require additional processing. This occurs when a die cannot provide certain physical features effectively, like holes, threads, or undercuts.

However, secondary operations may also be necessary to achieve other product properties. For example, some applications may require surface characteristics that aluminum alone cannot provide or a surface other than the smooth one provided by die casting.

4 Common Secondary Operations for Aluminum Die-Cast Parts

New silver die cast aluminum alloy wheel

The best known and most commonly applied secondary processes for die casting are trimming, machining, impregnation, and surface treatments.

You can often limit the time and money you spend on these post-cast operations through thoughtful die design and alloy selection. But they are sometimes unavoidable, especially if you want to obtain unique characteristics that aluminum die-casting alone cannot provide.

No. 1: Trimming

There are a few different reasons for trimming, but the most universal is to address the defect known as flash. Because of the high pressures involved during die casting, excess material forms around the parting line of the cast. It ends up looking like a ‘seam’ from the two (or more) mold segments.

Particularly for consumer products, you have to remove this excess material by trimming, which requires manual tools or a special trimming die.

Aside from removing flash, the manufacturer will need to trim other parts of the mold that fill with molten metal. These include sprues, gates, vents, overflows, and runners, depending on the design of your mold. While a robust die design can minimize the number and complexity of trimming operations, basic trimming is often unavoidable.

No. 2: Machining

CNC milling machine making a thread on an aluminium cast part

Die-casting is a precise process, so die-cast products generally don’t need special machining to meet dimensional tolerances. Instead, machining for die-cast parts is most often required when creating features unachievable through the die casting process.

Holes, threads, and undercuts are examples of shapes that are often very difficult and inefficient to cast. But by using a secondary machining process, you can create them.

Computer Numerical Control (CNC) machines allow you to quickly carry out any necessary machining operations. They also help ensure that the product more consistently meets quality tolerances.

No. 3: Impregnation

Some porosity is inevitable in any casting process, but certain applications such as pressurized equipment may require that the casting is completely leak-proof.

Impregnation uses a vacuum and a specially-formulated organic resin to remove the air from any open pores (voids) on the part’s surface and then fill and seal the pores.

Impregnation can be used on casts to reduce moisture retention and internal corrosion. It also helps inhibit fungal growth and seals leakages to ensure pressure tightness.

This process can be expensive, but the cost can potentially be minimized by performing pressure tests on all castings and applying the process only to those that do not meet specifications.

No. 4: Surface Treatments

Colorful yellow powder for powder coating

You can apply surface treatments to a product in several ways to enhance its physical and chemical properties after completing other processes.

Mechanical surface finishing operations, such as polishing, sanding, or deburring, can help improve a part’s surface finish. However, they are not as common for die-cast products which tend to have very smooth surfaces already.

On the other hand, abrasive blasting techniques, like shot blasting, can be used to roughen a smooth surface if required.

You can also paint, powder-coat, or anodize aluminum castings to enhance physical wear resistance, prevent corrosion, and improve appearances. However, it is crucial to do thorough research before implementing any of these coatings — their feasibility depends on your application, and the decision is not as straightforward as it is with aluminum extrusions.

Are These Secondary Processes Applicable to My Cast Part?

Aluminium part made by high pressure die casting

Subjecting your die-cast product to any of these processes can be costly, but they will impart properties that die-casting alone cannot. Depending on your application, these processes may be excessive or redundant but could also be an essential upgrade over the as-cast product.

If you’re unsure whether your casting product needs any of these treatments, you can contact one of our experts or visit our die casting services page to find out more.

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Aluminum Die Casting Alloys: Which One is Best for Your Project? https://www.gabrian.com/aluminum-die-casting-alloys/ https://www.gabrian.com/aluminum-die-casting-alloys/#respond Mon, 04 Apr 2022 22:21:52 +0000 https://www.gabrian.com/?p=22365 Once you have decided that the aluminum die casting process is suitable for your project, a crucial next step is deciding on the most appropriate alloy. The aluminum alloy you choose will substantially impact both the casting process and the properties of the final product. Because of this, you must make your decision carefully and […]

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Once you have decided that the aluminum die casting process is suitable for your project, a crucial next step is deciding on the most appropriate alloy.

The aluminum alloy you choose will substantially impact both the casting process and the properties of the final product. Because of this, you must make your decision carefully and take an informed approach.

Read on to find out which characteristics are the most important when choosing an alloy for the die casting process and which are the most commonly used in die casting applications.

Characteristics of Aluminum Die Casting Alloys

Determining the most suitable aluminum alloy for your application will mean weighing a wide array of characteristics. These comparative alloy characteristics follow the North American Die Casting Association’s guidelines, and we’ve divided them into two categories.

  1. The first category addresses alloy characteristics that affect the manufacturing process.
  2. The second covers characteristics affecting the properties of the final product.

We will cover some of the most important considerations below.

Alloy Characteristics Affecting the Casting Process

Die cast mold for automotive engine parts

The alloy you choose for die casting directly affects several aspects of the casting process, like how easy the alloy is to work with and if it is prone to casting defects.

#1 Hot Cracking

Hot cracking, also known as solidification cracking, is a typical die casting defect for aluminum alloys that can result in internal or surface-level tears or cracks. This casting defect is generally attributed to thermally-induced internal stress and strain, which form during the solidification process as the cast contracts. Certain aluminum alloys are more susceptible to hot cracking than others, and your selection should consider this.

#2 Die Soldering

Another common defect found in the die casting of aluminum is die soldering, which is when the cast sticks to the die walls and makes ejection difficult. It can damage both the cast and the die, so you should look for alloys with high anti-soldering properties.

While other aspects could be relevant to your process, these are two of the biggest processing concerns when die casting different aluminum alloys. However, while choosing an easy-to-cast alloy will keep your production costs lower, you also need to consider how the alloy selection will affect the final product.

Alloy Characteristics Affecting the Final Product

Die cast aluminum engine part

It’s common for the most sought-after properties of an aluminum alloy to be its mechanical properties, especially strength, ductility, and hardness. These attributes are fundamental and are sure to impact your final decision significantly. However, there are several other important qualities as well.

#1 Corrosion Resistance

Corrosion resistance, which is already a notable attribute of aluminum, can vary considerably from alloy to alloy and is an essential characteristic to consider depending on the environmental conditions your product will be exposed to.

#2 Wear Resistance

Wear resistance is another property commonly sought in aluminum products and can differentiate some alloys. It can be crucial for applications where the part is subjected to constant friction. Thermal and electrical conductivity can also be necessary for certain applications.

#3 Surface Treatments & Machinability

Finally, cast products often need to receive a surface treatment or be further shaped after leaving the die. Some alloys will take up these treatments or post-cast procedures more easily than others, and it’s something you need to take into account before choosing an alloy.

Some of the most common surface treatments for both die-cast and extruded aluminum parts are anodizing, electroplating, powder coating, painting, and polishing. Other standard post-cast procedures for aluminum parts include cold and hot working, machining, and welding.

Most Common Aluminum Alloys for Cast Products

Aluminum ingots for die casting

This section presents some specific aluminum alloys commonly used in die casting. These alloys are shown as named under the Aluminum Association system. If you’re unfamiliar with how casting aluminum grades are classified, you can read about it in our Aluminum Grades article.

According to the NADCA, the most popular alloys for die casting belong to the 3xx.x series, followed by the 4xx.x series, with alloys from the 5xx.x and 2xx.x series being somewhat less common but useful for specific applications.

The following table compares a few of the essential characteristics of popular aluminum alloys used in die casting. You can find specific technical values for each alloy at the featured links below.

Alloy Corrosion Resistance Resistance to Hot Cracking Anodizing Machinability Common Applications
A380 Fair Very Good Good Good Workbench vises and other hand tools, gear cases, lawnmower housings
A360 Excellent Excellent Good Good Instrument cases, irrigation system parts, outboard motor parts, hinges
383 Good Excellent Good Very Good Engine brackets, cylinder head covers, appliances, furniture, power tools
A413 Excellent Excellent Good Fair Outboard motor pistons, dental equipment, street lamp housings
B390 Fair Good Fair Fair Pistons, blocks, manifolds, and cylinder heads for internal combustion engines, brake cylinders
518 Excellent Poor Excellent Excellent Architectural castings, conveyor parts, marine and aircraft hardware fittings

 

Which Alloy Should I Choose for my Project?

There isn’t a single alloy that will be the best for every application. Because of this, you should carefully consider which aspects are the most important for your project.

Automotive engine parts made from aluminum die casting alloysFor example, alloy A380 is the most widely used casting alloy on the market and is suitable for many applications. Unfortunately, it underperforms when it comes to corrosion resistance, so depending on the application for your final product, A380 may not be the best option.

A360 is an alternative we use with many of our customers, and it performs much better in the area of corrosion resistance. It is more difficult to cast, but this challenge can be overcome in many circumstances. As such, we recommend that you consider A360 for most industrial applications.

In general, by noting which characteristics are more important for your specific situation, you will be able to tell more easily which alloy is best for your application. You can learn more about the die casting solutions Gabrian offers by looking at our die casting services page.

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Die Casting vs. Sand Casting: What is the Difference Between Them? https://www.gabrian.com/die-casting-vs-sand-casting/ https://www.gabrian.com/die-casting-vs-sand-casting/#respond Mon, 21 Mar 2022 05:15:06 +0000 https://www.gabrian.com/?p=22264 Determining the best casting process to use for manufacturing your next cast aluminum part can be challenging. While there are many methods and variants to choose from, two of the most commonly used processes are die casting and sand casting. These metal casting processes both offer a wide range of benefits to the manufacturer, which […]

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Determining the best casting process to use for manufacturing your next cast aluminum part can be challenging. While there are many methods and variants to choose from, two of the most commonly used processes are die casting and sand casting.

These metal casting processes both offer a wide range of benefits to the manufacturer, which can make it difficult to choose one over the other without detailed knowledge of their qualities. Luckily, this article will help you understand the main differences between these processes, and help you choose the one that best suits your project.

Defining Sand Casting and Die Casting

While we’ve discussed the many features and benefits of aluminum die casting in articles before, we haven’t covered sand casting as extensively. These processes are fundamentally similar in their basic principle: a mold cavity that reflects the desired shape of the final product is filled with molten metal which then solidifies into the final part. However, they are differentiated by the material used for the mold and the means for filling the mold with molten aluminum.

Die Casting vs. Sand Casting Mould Example

Left: Die Casting Mold, Right: Sand Casting Mold

In sand casting, the molds are made out of sand. Sand casting molds are formed by using a pattern and applying force to compact sand in the desired shape. When the pattern is removed, a cavity is left in the packed sand. Molten metal can then be gravity poured into the cavity and allowed to cool until it solidifies. Finally, the cast is removed from the sand mold and brushed to remove adhered sand.

On the other hand, die casting molds, known as dies, are made from machined steel and are reusable. Molten aluminum is typically injected between these dies under pressure from a horizontal position.

Die Casting vs Sand Casting – Key Differences

While these processes are relatively similar overall, the distinct differences in mold material and filling method have major implications on manufacturing efficiency and final product properties.

Sand cast part vs. die cast pars

Left: Sand Cast Part, Right: Die Cast Parts

Startup Time

Firstly, the startup time for these processes can be vastly different. Sand molds can be made very rapidly if the desired pattern is already at hand. Making a steel die for die casting, however, takes longer since it needs to be designed, machined, tested, and affixed to the equipment, which can be very time-consuming.

The setup and required machinery for die casting also mean much larger upfront costs than sand casting. The investment in die casting equipment generally only makes sense for higher production volumes.

Surface Finish

Another difference between sand casting and die casting is the surface finish of castings made from these methods. Sand casting leaves behind rough surfaces on parts because the compacted sand imprints its texture onto the cast. Specialized sands and other measures can reduce roughness, but this comes with extra cost. Die cast products, however, boast a very high-quality surface finish due to both the smoothness of the die’s inner walls and the pressure used to fill the die. Note that designed textures can also be added to die cast parts if desired.

Complexity of Parts

While both methods can create complex part shapes, die casting is often the preferred process for these types of casts. Thanks to pressure injection of the molten aluminum, die casting can make components with very thin walls. The pressure injection also leads to greater dimensional accuracy for cast parts relative to sand casting.

The following table summarizes the key differences between sand and die casting.

Die Casting vs. Sand Casting comparison

Which Process is Better for My Project?

Deciding which of these two casting processes is better for you ultimately depends on the qualities of the part you need to make and how many of them you want. For producing complex, small-to-medium-sized parts with high dimensional accuracy and a smooth surface finish, die casting is a clear winner. If a fast turnaround, a restrictive budget, or very large-sized parts define your project, then sand casting could be more suitable.

Sand casting is widely used to cast automotive engine blocks and pistons, bushings and bearings, aluminum furniture, as well as hydraulic and pneumatic components. Die casting, on the other hand, excels at making intricate machine and automotive parts, small toys, medical devices, and electrical and electronic components.

To see if die casting is the right process for your next project, check out our die casting services page. Our experts are happy to lend their experience and help you understand how to make your die casting project successful.

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