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Post-Processing Parts

When ordering custom parts, and especially 3D prints, you will need to post-process them before you can use them.

Machined Parts (CNC, Lathe)

All machined parts must be degreased before use even if the supplier claim to have degreased them before shipment. Degreasing can be performed in an ultrasonic bath and using isopropyl alcohol or acetone in a well ventilated area.

Warning

We recommend extreme care when using ultrasonic bathes on anodized parts as incorrect anodization can be removed by the bath. Also, never uses acetone or isopropyl alcohol with your ultrasonic bath as this may lead to fire hazard and/or explosions.

3D Prints

3D prints are usualy provided with loose tolerances and no threads. You must read the joined PDF of each parts to know which features need to be post-processed.

As an illustration, Figure 1 shows a 3D print with multiple toleranced features:

  • The top hole must be no less than ⌀10.0 mm and no more than ⌀10.1 mm diameter. This can usually be achieved by using a standard drill bit of 10.0 mm and passing the drill bit multiple times into the hole.
  • Multiple holes on the front face need H7 tolerance. This is usually performed using precision reamers which are available in standardized sizes (⌀3 mm, ⌀6 mm etc.). Larger holes, like the one of ⌀27 mm need to be machined using a CNC milling machine. In all cases, you can consult the assembly PDF to check which parts interract with the feature. Here, the ⌀27 mm hole should accept an optical barrel with minimal gap between the two parts - the CNC milling job can then be adjusted in consequence.
  • A M4 thread needs to be tapped on the side of the part.

Figure 1 - Example of toleranced features on a 3D print

Last but not least, you may use different technologies for threads depending on the usage of the part and the material of the part:

  • For FDM prints, thread inserts are usually preferred. This will be indicated in the drawing as "M3 INSERT" or "#4-40 INSERT". We regularly use CNC KITCHEN inserts for our prints and install them using a Weller soldering station.
  • For SLS parts, you may either tap directly the thread into the part or use an Helicoil insert. We usually recommend taping with Helicoil inserts to avoid damaging the thread too quickly.

Gluing

During assembly, you will have to glue some of the parts together. We recommend Scotchweld DP190 epoxy glue for all gluing operations. Always degrease the surface in contact using isopropyl alcohol.