Rapid Silicone Prototyping: Bridging the Gap

By Brooke Morgan

When the electrostatic spray method of powder coating came out in the 1960s, it revolutionized the industry. It was affordable, convenient, and environmentally friendly. To this day, its toughness and corrosion protection make powder coating ideal for many demanding applications. However, we all know achieving a good quality powder coated part isn’t as simple as just spraying powder on a substrate. A variety of critical processes and procedures must take place before the gun is in the operator’s hand. In many cases, masking is one of these crucial steps.

The masking process begins by covering the area(s) of a part that needs to be shielded during the powder coating process. This is generally done using special tape, rubber, caps, or plugs. In many powder coating situations, molded silicone masks are preferred as they can withstand the high temperatures and long cure times of powder coating. They can also reduce installation and removal times, while delivering higher repeatability. However, due to the way silicone is molded and cured, they traditionally require hard tooling.

This process holds long lead times as steel is cut, samples are molded and tested, and the design is tweaked. This process repeats itself again and again until the design is free of defects. Since time is money, speed matters. By compressing the design time, molding it, running tests, and shortening the approval cycle, resources can be freed; resources that can be deployed to accelerate the product launch.

Rapid prototyping using 3D printing, also known as additive manufacturing, has addressed many of the time- consuming issues related to tooling up, testing, and design tweaking, revolutionizing the prototyping world in the process. Parts, components, and products manufactured using 3D printing are created by depositing a thin line of material, most commonly specific types of polymers, metals, and ceramics, and building the part layer by layer. While not generally a high-speed process or feasible for high volume production, 3D printing brings significant advantages to prototyping and low volume production. However, it seemed all of the advances in rapid prototyping using 3D printing left silicone behind. Readily available “soft” 3D-printed materials may prove fit and form, but since they cannot survive the high temperatures experienced on powder coating lines, exclude function when it comes masking products. Seeing the value rapid 3D-printed prototyping could bring to masking, a team of design engineers from Echo Engineering & Production Supplies set out to change this.

After months of brainstorming, researching, and calculating how to improve the efficiency of the silicone masking production processes, the team had a breakthrough. Announced in November 2019 as “instant silicone prototyping,” the proprietary technology enables the Echo team to partner with customers to create and design a solution and provide functioning prototypes in a matter of days rather than weeks.

Non-migratory silicone prototypes can withstand up to 600 degrees Fahrenheit, are created in a matter of days, and cost hundreds, as opposed to thousands of dollars, to produce.

Design engineers Andrew Benson, Kyle Morris, and Sam Newblom shared the basics of the process, as well as key benefits and application examples. Without going too deep into the details of the proprietary method, it includes a lot of process expertise, 3D printing, and a mix of chemicals that result in a FDA-grade silicone. The resulting part has a durometer (or hardness) measurement of 50 to 70, and in as little as five days (depending on design complexity), the part is complete and ready to use.

Product possibilities using rapid silicone prototyping are nearly endless and the Echo team has created various caps, plugs, and a multitude of parts since the technology’s inception. This innovation may be applied to any non- direct OEM application for fit, form, and in some instances, function. The non-migratory silicone can withstand up to 600 degrees Fahrenheit, is created in a matter of days, and costs hundreds, as opposed to thousands of dollars, to produce. Typical part size is smaller than 8 x 8 x 6 inches, but larger sized parts can be created upon request.

Each part is a direct representative of the design intent functionality, meaning these parts share 95 percent of the properties found in standard compression-molded silicone masking components. This creates a more efficient communication network between engineers and the production floor. Kyle states, “It’s bridging the gap between production and prototyping. It will involve less time, less money, and that equates to a quick turn-around for OEM and MRO companies.”

When it comes to customer reaction to the new technology, Andrew recounts the experience of sharing rapid silicone prototyping with Polaris. “I was already in the middle of masking designs for them, so a co-worker and I showed them three potential prototype parts to view and validate.” The duo explained the product and asked if they had market interest. The initial feedback was positive; in fact, they were extremely interested and anxious to test the parts to see how they worked. “Once the parts were run, they decided they could approve certain parts off of that technology and go straight into production,” adds Andrew. Design changes can happen at the last minute at Polaris, so Brian Koehnen, their manufacturing technologist of new product inauguration paint, shared his perspective on the development. “It’s about timing for us. By the time we get a released part, often within a six-week window, we need to make decisions within a couple of months. Do the features work? Is it the right size?

Is it too tight? Is there folding going on? This silicone can go through the entire process, so it’s a huge deal for us.” Eliminating the traditional six-to-eight week wait time was a major factor for the powersport company. Now, if any changes occur along the way, they have the freedom to go back to the drawing board and start over.

Like any new technology, rapid silicone prototyping has some limitations. A rapid prototype can have elongation issues, size restrictions, and mass production shortcomings, making it nearly impossible to roll out hundreds of thousands of parts in a short time frame. However, upgrades to the technology are in the works. “Although we can’t say what our idea is yet, Sam is working hard to have our new method turnkey by the beginning of next year,” hints Andrew. Until then, rapid silicone prototyping is no doubt, the wave of the future.

Brooke Morgan is marketing associate for Echo Engineering & Production Supplies, Inc.