Stamped part tolerances (dimensions)

[Elastomatt]

Guys,

Help needed to identify a dimensional standard for punching parts from rubber sheets (10mm thick 70A EPDM in this instance). Our customer has referred to ISO2768, but this is for parts cut from sheet metal (or when metal is cut away).

If I should have posted this elsewhere then let me know...

Thanks

Elastomatt

 

[GrahamBennett]

The number of engineers that think rubber can be cut, moulded, extruded, etc to the same tolerances as metal bashing never ceases to amaze me.

The very, very best you can expect is +/- 0.08mm (+/-0.003") which is the M1 fixed tolerance quoted in ISO3302 Pt1 for precision moulded components.

 

[GrahamBennett]

Sorry - for 10mm thick sheet the very, very best you can expect is +/-0.15mm (+/-0.006").

 

[Elastomatt]

Thanks Graham,

We always work to ISO3302-1 (typically M2). The stamping process has left a curvature on the profile, this was explained to the customer (who didn't want to spend on tooling!). I'm thinking he will need a simple 2 plate compression tool if he can't accept the stamped profile.

Elastomatt

 

[GrahamBennett]

Not surprised by the curvature. A 3 plate tool might be lower cost than a 2 plate and will give any trapped air somewhere to go.