Plastic part crack 1

[TNME]

Hi,

I have an issue with my plastic part; please help.

A small metal ring assembles with plastic parts by a flat-head screw. When rotating and pulling the metal handle by hand over time, one of the plastic parts directly assembled with the metal ring cracked.

Is the flat head screw causing the crack as the force will focus on the angle when rotating? How can I fix this issue? If I change to use a rounded screw head, does it help? Thank you in advance for your help!

 

[JohnRBaker]

Some pictures might helps.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[SWComposites]

Maybe.
Photos and sketches of the configuration would help a lot to understand the details.
(do not attach them; embed them inline with the reply using the Image button).

 

[BEMPE16524]

yeah... some sketches, pictures etc please.

R.Efendy

 

[TugboatEng]

Screws in plastic? I suggest you research "creep". Polycarbonate is especially susceptible. Flat head screws support the conditions to cause creep due to the wedging action of the head. You need to consider fasteners that put less stress on the plastic.

 

[ctopher]

I'm not saying this is the problem without seeing pics, but I have seen this happen with (example) 82 deg flat head screws, 100 deg c'sink hole, or other way around.

Chris, CSWP
SolidWorks
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