Traditionally, injection mold tooling uses steel as the primary material, but it is not the only option. Today, aluminum molds have earned a place in the industry. Let’s explore aluminum injection molding and why it is worth your consideration in some cases.

Which should you choose: steel or aluminum? With clear pros and cons to each material, the answer depends on the specific needs of your projects. Partnering with an experienced and highly capable plastics manufacturer offers you the insights that you require to make smart decisions at every step, including in material selection.

The injection molding industry often defines molds by their class. This goes from Class 105, a prototype mold (e.g., a 100 piece one-and-done market test), to Class 101, which is built for extremely high production (e.g., making tens-of-millions contact lens cases). Xometry typically produces Class 104, 103, and 102 tools.

Moldmaker's choice of finish. Typically SPI B-3 to D-3 depending on geometry and drafts. Interior, non-cosmetic faces, are typically as-machined.

Xometry's injection molding service has decades of experience making plastic parts used in aerospace applications. Our strength is in saying "yes" - we help our customers make parts that others can't make. Aerospace companies large and small have found value in our highly customized services including:

Low production mold. Use only for limited production preferably with non-abrasive materials. Low to moderate price range. Also known as a Class IV tool.

Do businesses always want the durability of steel for a molding project? Not necessarily. Manufacturers choose aluminum most often when they need to quickly produce parts without requiring a very high volume. Since aluminum tools wear out faster, their optimal use is for lower part production volumes. They’re also an excellent choice when you need to rapidly produce prototype parts for testing, modification and redesign.

Let’s turn our attention to the “gold standard” for most molding projects: steel. Why does steel occupy the top spot over aluminum? The answer lies in three specific benefits.

Multiple-cavity steel tooling with full automation and overnight production workcenters for dedicated part manufacturing.

Using low-cost tooling allows molded parts to be produced very rapidly and cost-effectively--even when compared to 3D printing

Range of finishes from Grade 3 diamond / high polish to 320 stone low polish. Finishes include: SPI A-1 SPI A-2 SPI A-3 SPI B-1 SPI B-2 SPI B-3 SPI C-1 SPI C-2 SPI C-3 SPI D-1

Overall, with aluminum molds, you’ll experience lower initial costs, lower rejection rates and more opportunities to quickly begin production thanks to shorter tooling production times. With steel, you’ll enjoy durability for very high part volumes, less concern about wear and tear, and opportunities to create more advanced parts.

We are ISO 9001:2015 certified and AS9100D compliant. Only the top machine shops that apply to become suppliers make it through our qualification process.

As with aluminum, there are some downsides to using steel tooling. It’s crucial to include these factors in your considerations during the project planning stage.

For your free quote and design-for-manufacturability feedback, please upload your CAD file, or download our Injection Molding Design Guide. We want to earn your business. If you get a lower injection molding quote, send it to us and we will try to beat it.

Choose from millions of possible combinations of materials, finishes, injection molding tolerances, markings, and certifications for your order.

Range of finishes including matte, swirls, lines, and patterns. Finishes include: MoldTech - MT11010 MoldTech - MT11020 MoldTech - MT11030 MoldTech - MT112XX MoldTech - MT114XX MoldTech - MT116XX

Built for extremely high production. This is the highest-priced mold and is made with only the highest quality materials. Also known as a Class I tool.

There are several key benefits to using aluminum molds for plastic injection, not only its suitability for prototyping. Consider a few of the perks that make manufacturers choose aluminum just as often as steel.

Medium to high production, good for abrasive materials and/or parts requiring close tolerance. This is a high quality, fairly high priced mold. Also known as a Class II tool.

While there are some obvious benefits to using aluminum, there are several reasons why steel molds for plastic injection has remained a dominant choice. Aluminum comes with some disadvantages you must consider, including the following.

Injection molding is a common industrial manufacturing process with multiple businesses relying on the technique to produce items for every industry from healthcare to aerospace. However, not all injection mold tooling is the same—and the choice that you make regarding tooling materials for your project could have a significant impact on the outcome as well as your overall costs.

With Reliant Plastics, an injection molding provider with decades of experience, we can help you to make sense of your options and chart a course towards the best production decisions possible. To explore rapid prototyping with aluminum mold tooling or solutions for producing your parts at a larger scale, contact the Reliant Plastics team today for a free quote.

High-quality custom injection molded parts for the aerospace industry. AS9100D certified and ITAR registered. Get $500 off your first mold.

Prototype only. This mold will be constructed in the least expensive manner possible to produce a very limited quantity of prototype parts. Also known as a Class V tool.

Medium production mold. This is a very popular mold for low to medium production needs. Most common price range. Also known as a Class III tool.

In simple terms, aluminum injection molding is an injection molding process that uses mold tooling made entirely out of aluminum rather than steel. Companies often use this process for large production runs, and the long-term durability of steel is a common demand. However, advances in tooling creation make the use of aluminum a more viable solution for certain scenarios. There is nothing different about the molding process aside from the tooling material.