I apologize if this is in the wrong section, but it seems relevant.

I am an absolute noob at 3D printing, but recently my need for a specific, small part intersected with access to a 3D printer at work (Zortrax M200), so I figured now was a good opportunity to get into printing.

I am designing a clamp for smaller can capacitors that will hold them upright from a mounting surface. I would like the capacitors to snap into the clamp, but I am struggling to find information on how wide the opening to the clamp should be. It clearly needs to be smaller than the diameter of the clamp, but I'm not sure how much smaller it can be without snapping the clamp arms.

Is there a rule of thumb or general guideline for this type of geometry? I am using Z-ULTRAT, which is some proprietary filament made by Zortrax. It seems to be similar to ABS in terms of strength properties, but stiffer.

I don't have an image at the moment, but I can provide one tomorrow when I have access to the part files. The best analog I can think of is a LEGO figure's hands.


Edit: Per requests for additional information:

  • I am not sure what is considered a "thin" wall; currently, the clamp walls are 2mm thick at the thinnest point (where the push-in opening is).

  • I would like the walls to be just flexible enough to allow the cap to be seated without breaking - it is more critical that the cap is not loose in the socket.

  • The clamp is not going to be subject to repeated stress cycles - by the time the cap needs replacing, it's likely I'll need to print a new clamp as well.

  • With my estimations for cooling, I do not expect the clamp to see temperatures above 100C.

Edit 2:

Based on the link in the comments below, I came up with the following design: Clamp

The little nubbins in the back fit into the "neck" at the bottom of the capacitor to provide some positive lock. 220 degrees of surround with 4mm thick arms - I think this should work.

  • $\begingroup$ please taka a look here 3dprinting.stackexchange.com/questions/771/… $\endgroup$ Apr 19, 2017 at 11:21
  • $\begingroup$ Thank you! I must have missed that post when I was searching through the site. $\endgroup$
    – Chris M.
    Apr 19, 2017 at 11:56
  • $\begingroup$ I think your clamps are hanging in the air. It's feasible (to print in the air as same as to print with support material) but I'm sure it can be redesigned to not hang :) $\endgroup$ Apr 20, 2017 at 7:59
  • $\begingroup$ I don't understand what you mean by "hanging in the air". Do you mean the clamp arms are unsupported from below, and thus difficult/impossible to print in that orientation? Would it be better to lay the clamp on its "back" (which will have to be flattened - not impossible) and print it that way? $\endgroup$
    – Chris M.
    Apr 20, 2017 at 10:40
  • $\begingroup$ yes - i was refering to unsupported clamps but no - definitely orientation of your detail is proper (potential issues described in link above). please take a closer look on the design in the link - there are clamps which are self-supported $\endgroup$ Apr 20, 2017 at 12:14

2 Answers 2


I am sure someone much smarter will be able to point you towards datasheets and maths equations that will tell you exactly what you could/can't do, however, I would say it depends on a few things:

  • Material - some materials have more give/flexibility, others have less. Depending how hot you expect the caps/surrounding components to get may also influence choices.
  • Wall thickness - Are you just after a 'thin walled' print, or something more solid. Thinner walls tend to be more flexible.
  • Reusability - are you going to snap the cap in once or twice, or thousands of times?

I would hazard a guess that about 210-220 degrees of "surrounding" would be enough.

Can you try it and see? Or do you only have one shot?

  • $\begingroup$ see edits. I'm not limited to one shot, but I'm trying to minimize the number of print jobs I have so I'm not occupying the printer needlessly. $\endgroup$
    – Chris M.
    Apr 19, 2017 at 10:36
  • $\begingroup$ As stated, not an engineer or other kind of material scientist, but your design looks like it should work! $\endgroup$
    – AndrewP
    Apr 20, 2017 at 2:46

Based on the links and insights provided, I was able to adjust my design to that shown in Edit 2. I opted to instead have it professionally printed via Sculpteo for a very reasonable price, and can say that the design works as intended.


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