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SHOTSHEEN™

The Production Finish For Multi Jet Fusion


SHOTSHEEN™

SICAM Corporation has had one great mission since 1990: To be the industry leader in providing a full range of Engineering, Rapid Product Development, and Manufacturing Services. Great leadership, especially in such a rapidly developing prototype industry, comes with great responsibilities such as constant adaptation and innovation. Business innovation is a process that runs from a mere idea, through development to implementation. SICAM is proud to present SHOTSHEEN™ for a new production finish for Multi Jet Fusion.


In moving from 3D printing for prototypes to additive manufacturing for production parts, additional factors come into play. This article discusses the usage of Multi Jet Fusion for production and how it relates to surface finish.

Since we first started 3D printing in 1990, one question on finish has always been “Can we make it look like an injection molded part?” The answer, of course, is “Yes,” and we have been doing it for years! However, the drawback in our former methods is that it requires manual post-processing operations that are time-consuming and quite expensive. The primary application for this has been presentation models for marketing and photo shoots. This manual process is too slow and costly to make it feasible for production.

We already know that Multi Jet Fusion has the speed to be used for low-volume production, but can it obtain a finish that is acceptable for production use?

The challenges are:

  • Can the finish be made consistent?
  • Can the finish simulate common injection molded parts?
  • Will it require a post-process operation?
  • Will it be economically feasible for production?
Standard Finishing Operation:

The standard finishing operation procedure for Multi Jet Fusion is to manually glass bead the parts to remove excess powder and then dye it black. While this method produces a finish better than most achievable 3D-printed technologies, we still believe it falls short of being an acceptable finish for production parts. This shortcoming is due to two factors. First, the manual operation causes inconsistencies in part finish, part dimensions, and the finial finish after dyeing. The second issue is that the glass beading is a manual operation that contributes to added labor costs.

The image to the right show the results of a manual operation, including, but not limited to, the following inconsistencies:

  • Areas of black and white shows how manually glass beading does not cover the part consistently over all the surfaces.
  • Corners and edges have residue powder.
  • The ideal sharp edges are softened by repeated manual operations.
  • Dimensional variations occur because of nonuniform removal of powder.
The Solution SHOTSHEEN™ :

In investigating a system that would resolve these issues, we purchased and installed the DyeMansion finishing system to post-process the parts. The finishing system consists of two machines that are compatible with any geometry.

Powershot C:

The first machine, the Powershot C, automatically glass beads with multiple nozzles in a rotary barrel to evenly de-powder the parts with a uniform cover while maintaining any sharp details. The automatic cycle finishes with a final air cleaning to remove any remaining powder and glass media.

In the images at the right, the powder is removed with the DyeMansion Powershot C, as opposed to a manual operation. The powder-removal is consistent across all surfaces and both, recessed and extended, lettering come out crisp and clean. The internal surfaces showed vast improvements with correct de-powdering in deep pockets and holes.

We made progress but there was still room for improvement. The finish was still flat and grainier than what was desired.

Powershot S:

To further develop the finish, the parts are processed through an additional automated cycle in the DyeMansion Powershot S machine. This machine peens the parts with a fine shot that enhances the surface texture by adding a glosser finish. Furthermore, it reforms the hardness of the surface, making it more scratch-resistant. While we haven’t tested this yet, the process will also increase the seal on the outer surfaces

Upon completion of the Powershot S process the part now has the enhanced SHOTSHEEN™ finish and is ready for dyeing.

Standard Finish vs.SHOTSHEEN™ Finish:

The image on the left displays the results of manual glass beading and dyeing.

The image on the right displays the object with the enhanced SHOTSHEEN finishing operations and the final dyeing. Evidently, there are distinct characteristics of both the pieces.

 
Conclusion:

Our challenges are completed… We call our process SHOTSHEEN™.

  • Can the finish be made consistent? Yes!
  • Can the finish simulate common injection molded parts? Yes, it looks like a Moldtech finish.
  • Will it require a post-process operation? Yes, but it is uniform.
  • Will it be economically feasible for production? Yes, the finishing is automated.

At SICAM we have developed a custom blend of media to give the optimum finish for these parts. These machines turn porous, sensitive, plastic parts into durable, finished products with minimal manual labor.

Below you can see more examples of Multi Jet Fusion parts with the SHOTSHEEN™ finish.

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