Prototyping and Production Beyond 3D Printing

November 19, 2014, 1:00 am

As my colleague Rich Walters mentioned in Prototyping Beyond 3D Printing, a single rapid prototype process may not suit all your needs. Common build artifacts such as stepping can be a distraction and they require tedious hand finishing to create a production look. Recently LSR partnered with Solidscape, creators of the finest process in 3D printing in the industry, to offer our customers ground breaking technology and quality. The best part is better deliverables at a lower cost with higher profits and speed to market. While there are multiple options in the 3D printing industry, this article will focus on the Solidscape process and how we find it valuable in new product development.

Unlike other processes, the Solidscape process is both additive and subtractive. It first lays down a very thin layer of build and support material, then each layer is precisely milled to create the highest resolution, most detailed 3D printed parts in the industry. The tolerances, control, and precision of this process are incredible and off the chart.

This is important because master pattern and mold makers have to finish patterns to the highest degree possible. Our end goal is to make prototypes that are as good as production. When we mold a pattern to create silicone tooling, it needs to be perfect in every way. The silicone tool picks up every whisper of detail and finish, good or bad. Therefore, having a high quality 3D printed pattern reduces finishing time and creates better end results: happy customers, reduced cost, higher profits, and shorter lead times.

Solidscape Wax part being printed
Solidscape Wax part being printed
Solidscape Wax part in silicone mold
Solidscape Wax part in silicone mold
Silicone mold made using Solidscape wax master.
Silicone mold made using Solidscape wax master.
Urethane cast part from Silicone mold
Urethane cast part from Silicone mold

Solidscape patterns require little to no hand finishing before lost-wax casting or use in the pattern making processes. Because the tolerances, surface finish and detail are so precise, a pattern maker can create a part or tool directly from the original 3D printed part. To be able to take the part straight from the 3D printing machine and mold it is an incredible advantage. My only other experience with anything close to this is with Polyjet patterns. As amazing as they are, Polyjet only prints at about 600 dpi versus Solidscape patterns in their highest resolution at 5000 dpi.

MEMI CNC brass prototype
MEMI CNC brass prototype

We used machining and various prototyping processes to create beautiful production and show quality models for MEMI. They make high-technology fashion jewelry and hence requires beautiful yet functional prototypes. Initially, we milled dozens of sets of parts for the bracelet's metal parts. We carefully polished each part, plated, and then assembled each bracelet with highly detailed urethane castings that we created out of silicone tools. The machining costs for the 8 highly detailed miniature brass parts needed per bracelet were very high and took many weeks to complete. The crisp precision and watch-like detail was required so the parts fit together perfectly. We had to start looking for a faster, more cost effective way to prototype the samples needed.

Partnering with Solidscape, we have a shared mission and core values to introduce machines and processes to new industries: We aim to inspire, teach "outside the box" thinking and to show that this smaller, more cost effective machine can do things the much larger expensive systems could never dream of doing.

MEMI Case Study

For MEMI, we created multiple sets of lost wax castings for the metal parts previously machined from brass. The fidelity of the metal castings created through this process is incredible. It all starts with a perfect wax. Perfect wax results in perfect metal parts! Traditional methods of expensive time consuming metal tooling are used to make production waxes in most foundries. The Solidscape wax patterns created directly from the digital models are put through the foundry process providing a very direct route from digital file to finished casting.

Multiple sets of MEMI parts were created in wax through the Solidscape process. Shrink was calculated in the wax patterns so that metal parts would come out their intended size. From the wax patterns we then cast in brass. The wax patterns and cast metal parts were some of most detailed, tight tolerance, quality parts we have seen. With only light finishing, these metal parts cast from this process are ready for assembly. The following are just a few of the benefits discovered:

  • Less finishing time
  • Parts fit better with perfect tolerances
  • Crisp and amazing detail
  • Consistent quality on run of parts
  • Less expensive and faster process
  • Ability to make design changes without expensive hard tooling revisions or machining
  • Ability to cast in any metal allowing complete design flexibility
  • Production worthy first articles for design review
  • Ability to create functional production quality parts for marketing
MEMI cast brass parts from Solidscape Wax

Prototype and Production Applications

Solidscape provided our 3D lab a complex industrial part in wax from their process. From that we directly created silicone tooling. Zero finishing was done to this pattern before tooling. From this initial tooling we created urethane castings of various hardness (durometer) demonstrating use of Solidscape patterns in the silicone tooling urethane casting process. Urethane casting is a generally thought of as a prototype process for creating production plastic injection like castings in the 1 - 1000 range.

We then created production molds based on the original core and cavity made from the original Solidscape wax pattern. Essentially we made molds from our mold faces, thus creating a production process to create multiple cavities for larger runs of parts. The parts created out of silicone tooling, done correctly, will be the best you will ever see. These parts will make people look twice to see if the parts came from a metal tooling. Untold millions of dollars worth of real world production polyurethane parts are run for medical companies like General Electric for MRI scanning machine housings and the like. Even a company as large as GE will utilize this silicone tooling urethane casting process to create their production housings as they are not likely to build a half million dollar metal tool to build only a 100 of a single part in a year.

MEMI cast brass parts from Solidscape WaxMetal Mold Face cast from 3D Solidscape parts.
Metal Mold Face cast from 3D Solidscape parts.

This process represents a radical shift in the way things can be done. Some have characterized LSR's research and development with Solidscape as a "disruptive process." We agree, and are excited to give our customers the best of the best using a new and radically effective way to get things done.

For more 30 years, I have watched the birth and growth of the rapid prototype industry. When I started in this business, everything was built by hand from drawings. I have often said aloud, if the old masters were here today, they would be using these machines to do incredible things. They would be doing that "outside the box" disruptive thinking. This is an exciting, amazing time.

Because of the detail and precision, build times are long with the Solidscape process. This isn't a concern for us as it is much more important that the parts be precise, detailed, and accurate rather than lightning fast. Once wax patterns are created, you have little to no finishing time. Furthermore, you have crisp accurate detail and minimal second operations or clean up on production parts. As a result, you can make up for the slower initial build times quickly, and then do laps around other processes.

In our initial work with the Solidscape technology, we have had many "ah ha" moments. The thing that has us most excited is creating metal mold faces that are placed into metal mold bases for plastic or wax injection tools. These are prototype tools that can create production quality waxes or plastic injected parts in quantities of 1 to 1,000 and beyond. Often the tools and inserts are hand operated, but automated tools are also possible. Some of things you can do with this process would be too costly, difficult or even impossible with traditional machining and tooling methods. That's the sweet spot we like!

This isn't a replacement for machining or traditional machine tools. Integrating the best of machining, rapid prototyping and the creative "outside the box" thinking is the key to this ground breaking disruptive process. A friend and mentor, Dan Straka from Interpro Models said it best, "old school meets new school." Rapid prototype machines aren't a replacement for the model maker. LSR and Solidscape are re-introducing creative genius and the human element back into prototyping and production in a big way.