3D Printed Part Smoothing Breakthrough

[StrangerBandFan]

I just started using 3D printed parts in my builds and faced the challenge of getting rid of the layering lines. I use Shapeway to print my parts. They have a large variety of materials to choose from and each has it's own unique characteristic. For highly detailed parts, I always use their Frosted Extreme Detail (FED) materials because they use a printer that has 16 micron thick layers, pretty much the highest resolution you can get. The minute layer ridges still show up, especially on things like 1/12 scale Weber carbs, and painting just exaggerates them.

Check out my post in On The Workbench of my 1/12 Ford GT40 build for some pics of parts I've had printed. The post is titled as Tamiya, but it's a Trumpeter model. My goof! All of those pics show parts that haven't been smoothed yet.

The web is full of ideas on how to smooth the layer ridges off these parts. Sanding, epoxy washes, acetone and ethyl acetate vapor chambers and air erasers. I tried them all with limited or no success. The air eraser idea gave me an idea. I bought an ultrasonic jewelry cleaner, partially filled it with baking soda, put some test parts in and ran it through four 480 second cycles (the max the cleaner will run). What a huge difference! then I used an electric toothbrush (no, not the one I use on my teeth :-) ) and some Tamiya red cap course polishing compound and ran it all over the parts for a couple cycles of the brush and they came out as smooth as a baby's bottom without losing any of the fine detail of the parts! Success at last.

Word of warning, the ultrasonic cleaner relies on being filled with liquid to cool the electronics inside it. When using baking soda, it gets VERY hot unless you let it rest for a few minutes between cycles. Use with caution, I'm not responsible if you burn your house down. Now I put the cleaner in the frig for 30 minutes before I start and wait 10 minutes between cycles and it barely gets warm to the touch. I've got a second cleaner full of water and TSP (tri-sodium phosphate, a common cleaning agent found in the paint section of any hardware store) to clean off the baking soda and polishing compound.

I just started this process, and want to post pics of a set of parts all the way from rough from the printer to final paint. I'm only part way done and will post them soon. I was so excited figuring this out I thought I'd share the basic info now in case anyone else wants to try it. Please post your results and any other ideas you have.

 

 

 

[Foxer]

Very interesting.

Have you tried Shapeways new Black High Definition Acrylate?

[Len Woodruff]

Interesting. 

[my66s55]

Understanding the print spects will help you understand what causes those lines. 3d printing is done in most cases in layers. When an object has an angle, it creates a situation of lines, Vision a series of steps. The ones used to climb. The greater the angle, the greater the step. The layer size may be 19 micron, but if the xy is 100 microns your going to get steps. X being left to right and y being top to bottom. The black high definition printer is a desktop u.v. resin printer. The same technology I use. If I had to guess, I'd say that it's one of the new fast printers that can do an hour print in 10-15 minutes. The resin is Fun-to-Do deep black which prints in great detail and has a shrinkage of 5% or less.

For smoothing, I prefer to use Duplicolor scratch filler whenever I can, but I don't have much problem with lines because I print at 50 micron layer height and 70 micron xy.

[Warren D]

Interesting process, I'll be watching for additional posts.