Press fit with Two Plastic Parts

[Slothpur]

I have attached a PDF of a part I am designing. I am wanting to press fit these two parts together but I am unsure if my geometry is allowed. I didn't quite do the 2*d for the length of the shaft. I am wanting to use FDM to prototype these parts. I am asking them to make it out of ABS-30 which should be stronger than regular ABS. Any suggestions on this design are greatly appreciated. BTW, I am wanting to stay with a press fit design instead of using a snap fit design for cost and some other reasons.

Thanks,
JP

 

[insideman]

Many errors here:
1. Heavy section at base of stud and around hole. Revise to constant wall.
2. .004 interferance out of .09375 is too much.

3. 3 degrees is way too much. Consider 1/2 degree.

4.Fits like this will invariably fail over time due to relaxation. Use solvent bonding instead.

 

[Pud]

As above - could use cyanoacrylate adhesive for speed instead (clearance required)

Cheers

Harry

http://www.tynevalleyplastics.co.uk

 

[loughnane]

Thoughts

I would go with .003" nominal, and tolerance each feature's width @ .001.

I assume you are injection molding these parts, in which case insideman is right, your wall thicknesses seem out of whack.

You can probably even get away with 1/4 degree, assuming your ejector pins are placed along the tongue in your tongue and groove.

My first guess would be ultrasonic welding.

You might consider press fitting pins into bosses inside your tongue and groove perimeter (I assume it goes all the way around)

Chris Loughnane - Product Design

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