Friday, September 8, 2017

Post-Processing Tips for 3D Printing Trophies: Part 2

Whether they’re Oscar statuettes, youth sports participation awards or anything in between, we tend to think of trophies as shiny metallic objects. But there’s no rule that says they have to be gleaming silver or gold, especially if you’re making them with a 3D printer.

In Part 1 of this post, we shared methods for giving 3D-printed trophies a finish that looks like chrome plating. Now, let’s explore a different approach to post-processing for plastic pieces made with FDM (fused deposition modeling) printers.

After successfully completing our Cisco trophy, we decided to create small trophies for each member of the winning team at our annual fundraising golf tournament. Our Director of Instruction, Tom Meeks, came up with as design featuring a golf ball atop a cylindrical base. And instead of the standard metal-plated finish, Tom wanted the ball to be white – like a real golf ball – and the base to look like wood. 
Finished trophies for YouthQuest's golf tournament
We had initially ruled out using FDM machines for the project because, even when they’re set for the finest detail, the printing process always leaves visible striations as layers of melted filament are stacked up. We wanted to create plastic parts with smooth surfaces – and do it with a minimum amount of effort.

One popular method is sanding the piece and brushing on an epoxy product such as XTC-3D or, for plastics like ABS, Acetone. But that can be time-consuming, mixing the epoxy can be messy and Acetone is potentially dangerous to you and your print if you’re not careful.

Tom’s search for a better solution led him to discover Polymaker. The company makes a PVB filament called PolySmooth, which prints like PLA, but can be smoothed with ethanol or isopropyl alcohol. Post-processing is done by putting prints in the Polysher, a device that generates an alcohol mist inside a see-through tank. Print layer lines virtually disappear, leaving a surface that looks polished – exactly what we wanted for our “golf ball.”
Ball after smoothing in Polysher
To print the base, we could have used any number of filaments made with a mixture of wood and thermoplastic, but they tend to cause extruder clogs. Instead we went with Polymaker’s PolyWood, which doesn’t contain any wood particles but looks and feels much like genuine wood, and can be textured and stained just like the real thing.
Trophy base made of PolyWood before staining
Having filament that’s affected by alcohol also opens up some interesting possibilities for adding colors to 3D printed pieces in post-processing. Tom had been experimenting with the Craftwell eBrush, an electric airbrushing system that uses alcohol-based color makers, before he learned about PolySmooth filament. He’s planning to have our advanced 3D ThinkLink students try using the eBrush on PolySmooth parts to see what kind of results they can produce during our next Immersion Lab Week.

   

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