Acceptable misalignment between holes on mating parts?

  • Thread starter Thread starter Steven9
  • Start date Start date
  • Tags Tags
    Holes parts
Click For Summary

Discussion Overview

The discussion revolves around the acceptable level of misalignment between screw holes on PCB boards that are being fastened together using HEX spacers. The specific concern is whether a 0.1mm misalignment is problematic, given the manufacturing tolerances typically associated with PCB production.

Discussion Character

  • Technical explanation, Debate/contested

Main Points Raised

  • Steven raises a concern about a 0.1mm misalignment of screw holes on a PCB designed by a different team, questioning if this will pose a problem during assembly.
  • MRFMengineer suggests that the acceptability of the misalignment depends on the drill size specified, indicating that a 3.3mm drill size could accommodate the misalignment.
  • Steven confirms that a 3.3mm drill size was indeed called out for the holes.
  • Another participant notes that this drill size allows for a positioning tolerance of ±0.150mm, implying that the misalignment may be acceptable if tolerances do not compound negatively.
  • Steven expresses gratitude for the insights, indicating that the discussion has clarified his understanding of the situation.

Areas of Agreement / Disagreement

Participants appear to agree that the 3.3mm drill size provides a sufficient tolerance to potentially accommodate the 0.1mm misalignment, but there is no consensus on the overall impact of tolerances in this specific case.

Contextual Notes

The discussion does not resolve the potential effects of cumulative tolerances in the assembly process, leaving some uncertainty regarding the final outcome.

Steven9
Messages
4
Reaction score
0
Hi,

I am working on a design that has a stack of CSK PC/104 pcb boards fastened togther using HEX spacers.

One of the PCB boards is being designed by an different design team. They have already manufactured their board but it turns out that the screw holes for the Hex spacers are mislaigned to the board that it will be fastened to by 0.1mm.

The holes are M3 clearance. Does anyone Know if this will cause a problem during assembly? Is 0.1mm an acceptable misalignment? I believe normal PCB manufacturing tolerance is 0.075mm

Thanks,

Steven
 
Engineering news on Phys.org
It depends on the drill size that was called out, if it was 3.3 mm, then it will probably be fine.
 
Thanks MRFMengineer, its was a 3.3mm drill size that was called out.
 
So, that gives you +-0.150 mm positioning tolerance, so as long as the engineering gods did not stack up all the tolerances against you, it should work.
 
Yeah, hopefully we will get a bit of luck! Thanks, for your comments...things a bit clearer now!