self tapping screw to polycarbonate material

[dogbural]

Hi,

I am now trying to design injection moulded parts with polycarbonate that requires to accomodate Dia 4.4mm self tapping screw. To do that, I would like to know what is the correct hole size in the moulded parts.
Do we have any self tapping chart against polycarbonate? I could see ones for metal sheet against self tapping screw; but no luck to have a chart for polycarbonate.

Thank you in advance.
MK

 

[btrueblood]

I'd advise against tapping into PC, unless you are ready to do some optimization of your mold and molding process. Use a molded-in insert instead.

But, if you must, read this too:

https://www.eng-tips.com/viewthread.cfm?qid=272928

oh, and:

https://www.theplasticshop.co.uk/pl...exan_polycarbonate_sheet_processing_guide.pdf

 

[cowski]

Will the screw boss be designed into the plastic part? If so, I'd suggest using a screw designed for plastics, such as a Plastite[®] type screw. I've had good luck with these; I've been designing plastic injection molded parts (mostly ABS and PC) for 20 years.

https://www.semblex.com/EN/pdf-files/technology-files/plastite-pdf/

 

[berkshire]

Polycarbonate has a bad habit of cracking radially from the center of a self tapping screw. I suggest that you use a molded insert for your screw and a clearance hole for the PC.
B.E.

You are judged not by what you know, but by what you can do.

 

[TugboatEng]

Or a well nut.

 

[Pud]

A Plastite type screw will be fine. Choose a manufacturer and they will give you the hole size and geometry for PC.
Note: you must ensure the screws are thoroughly free from oils and greases before use.


Politicians like to panic, they need activity. It is their substitute for achievement.