Smoothing Polyamide Natural (MJF)

Hi. I designed and ordered a 3d print out of natural polyamide. I received my order and am very satisfied with the result. The project is a miniature marble machine that uses small steel ball bearings (6 mm diameter).

My problem is that I didn’t design some of the down-ramps steep enough and some of the balls get stuck.

Two questions:

  1. Can I use a small file and/or fine grain sandpaper on natural polyamide to make it smoother?
  2. Is there a household product or chemical I can apply to the polyamide for a smoother surface? (like nail polish, wood finish, etc.)

I do not have a test piece that I can experiment on and was hoping someone with experience can give me some direction. Thank you!


Could you please let me know your order number and we will be happy to help and contact you directly.
Thank you n advance.

Best regards,

Oh, hi Anna. I didn’t want you to think there was anything wrong with my order. I’m really impressed with it. I’m a beginning designer and just miscalculated how steep I needed to make it.

To answer my first question, I experimented on one part with a metal file and found the polyamide to be impressively strong. I instead tried a Dremel tool and was able to smooth off a corner. I believe it melted the material a little as it turned black, but it worked great.

I will next experiment with a chemical or paint to try to smooth the ramps a little more. Thank you.


I asked your order number as it would be easier to understand which model are you talking about and found a suitable solution for you.

Kind regard,

I misunderstood. Thank you Anna, however, I have found a workaround that did not require changing any surface. It’s hard to explain without photos. I will share a video of my finished product eventually. Thanks again.

Here’s a video of it operating.

The dark stains on the ramps are oil residue off of the balls (I was trouble-shooting something else). Anyway, I’m a complete beginner so not bad for my first 3d print. Thanks again to the team at imaterialise!

Looks awesome Joe! It’s mesmerizing :astonished:

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