Measuring Parting Line Mismatch/Flash

[Derrickt14]

Hello,

I was wondering if I could get some help with measuring techniques on the measuring parting line mismatch/flash.

The dimension stated on the print is a linear dimension .380 ± .005. This dimension also has a parting line that runs through it on each side of the dimension.

There are two notes on the drawing that state Max Flash: .010 and another note that states Max Parting Line Mismatch: .005.

If we were to measure the dimension with the parting line not included, we are within the specified tolerance. If we measured with the parting line included, we exceed .385. But the parting line mismatch falls within the note tolerance. This drawing is IAW ASME Y14.5-2009 and I know within that standard it does reference Y14.8. I am from the machining world and just moved into the molding world. The way I interpret this is to avoid the parting line when measuring as the parting line is controlled by a Note on the drawing, but I could be wrong.

If someone could please help me out with this, I would appreciate it greatly!

Thank you!

 

[MintJulep]

You're sure to get many opinions here.

But the only one who can tell you for sure is the part's designer. You need to ask them.

 

[3DDave]

Per Y14.8, mismatch is additive to part dimensions.

It is a recognition that the work of the pattern maker cannot stop the mold maker from doing whatever they are doing, values accumulate at each step. Even CNC or EDM'd injection molds are often placed as inserts and aligned as separate parts in the mold cavity.