You have a great idea for a new product based on the demand of your current lineup. It’s going to be a low volume idea, but it should be great for high profits. When you approach your injection mold maker with the idea, you ask if the tooling can be ready any sooner than the normal 16 weeks for a steel mold. Your mold maker offers aluminum, which you never knew was an option. In certain instances, aluminum may be a better choice than steel. Here’s what you need to know about aluminum molds:
The Benefits of an Aluminum Injection Mold
- Cost: Aluminum molds can be cheaper than steel molds. Some tooling shops may quote as little as half price of a steel mold due to their ability to quickly manufacture the mold and have it ready for first part trials.
- Timing: Aluminum molds can be produced faster than a steel mold. Some molds can be ready in as little as three or four weeks, where a steel mold may take double or triple that time to produce. Timing will depend on many factors including surface characteristics, inserts for special features, and part complexity.
- Durability: Aluminum molds may withstand of thousands of shots, and with special care up into the hundred thousand range for parts. That may be done in a year, or could be stretched out over multiple years. If you plan to just run a small quantity every year, an aluminum mold may be perfect for your product.
- Modifications: Aluminum is harder to modify, so it should be used for parts that won’t require many changes or design revisions.
- Part Resin Materials: Aluminum molds can use resins similar to a steel mold. More than 100 different materials can be used including ABS, PC, PP, LCP, POM, and liquid silicone rubber. Typical uses are thermoplastic and thermoset resins. One caution to using abrasive materials is that they can wash out or damage the surface design over time. Aluminum is softer than steel, and can lose the surface grain or characteristics easier with an abrasive resin.
- Heat Dissipation: Aluminum has better heat dissipation properties than steel and may not need the cooling lines associated with a steel mold. This can reduce mold complexity, reduce your maintenance time and cost, and also reduce the machine setup to adjust the cooling temperatures and flow.
- Mold Material: There are three primary aluminum types used for aluminum molds, which are Hokotol, Alumold 500, and QC-10 by Alcoa.
When Should a Steel Injection Mold Be Selected?
Given the advantages listed of aluminum, it is not always the best option for your new product. Steel has a storied history going back decades as has proven to last year after year producing millions of parts with tight tolerances. These are some of the reason steel may be a better choice for your new product:
- Amortization cost may be better over the lifetime of the part. Steel injection molds can produce millions of parts with the same quality, where aluminum typically will not keep the quality at high volumes.
- Steel injection molds can utilize designs with more than eight cavities.
- Part complexity can be increased with intricate designs and multiple inserts. Steel has the ability to hold tighter tolerances over a longer period of time or for a larger number of molding shots.
- Steel molds have more finishing options for surface texture than an aluminum mold. If you have a specific texture needed for customer marketing, or need a deeper texture for a specific function, steel may be the better choice.
One of the questions that needs to be answered between a steel and aluminum mold will be who will run the mold. Steel is more common and requires slightly different setting on the molding machine than an aluminum injection mold. It’s not impossible to figure out how an aluminum mold needs to run, but that time and material will not be required if your molder is experienced with an aluminum mold. Included in that experience with aluminum molds will be the knowledge that certain cleaning is needed with specific cleaners to address gas build-up along the parting lines.
Is There a Hybrid Option?
You may need a lower cost option with extra durability in certain places in your injection mold, and there are options for hybrid injection molds that mix steel and aluminum to get the best of both materials. Steel is the more expensive option for a 100% steel mold, which includes steel slides and inserts. For deep draw areas that may be difficult to get chilling water to, an aluminum insert may be a perfect option to get the intricate design and the quality for your design. On the converse, you may need more durability in particular areas of an aluminum mold, and a steel insert may do very well in that instance. Your mold maker should be able to choose which mold will be best suited for your production volume, available budget, and schedule.
We have an elite team that produces world-class prototypes and products, and can offer support to decide who and where to send your future business. Give us a call at (425) 339-0288 or email us at info@sealectplastics.mystagingwebsite.com. In the end, the injection mold material and process chosen will benefit your product design by having a prototype made to show employees, potential customers, current clients, and future investors. We look forward to offering support and advice on your next project.
Matthias Poischbeg was born and raised in Hamburg, Germany. Matt moved to Everett, Wash., after finishing his bachelor’s degree in business in 1995 to work for Sea-Dog Corporation, a manufacturer, and distributor of marine and rigging hardware established in 1923.
In 1999, Matt took over the reins at Sea-Lect Plastics Corporation, a sister company of Sea-Dog and a manufacturer of plastic injection molded products with an in-house tool & die shop. Matthias Poischbeg is also a contributor to Grit Daily.
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