[spock]

I just built 2 sets of mold inserts for a customer, who specified alot of engraving for their product info on a container. I have built these before, the old spec for the engraving was .02 wide letters at .015 deep, but there was only about 15 letters total. Thay didnt have trouble sticking.
The new ones have about 50 letters, .03 wide at .012 deep. They ran the first one fine (bigger container) but the smaller one is sticking bad. I think the bigger container is catching more ejection air and helping it out of the cavity.
Also, these mold are alum, they have been glass bead blasted only. We usually have them "teflon impregnated hardcoated" but the customer needed to run these and we didnt have the time to coat them. I dont think that is an issue.
Question is, is there a hard and fast rule about the amount of engraving, and what is too much?

[johnd]

It would seem that if the engraving is comining out in the part to be visible in the finished part you should be able to eject the part from the mold. What is the material? Are the molds male or female cavities? Is there any stripper mechanism other than air blow off. What is the starting gauge and the finish gauge?. Is there consistent material distribution. I have seen alot of times where a customer has designed a part, specified a material, specified starting gauge, and could not get an acceptable part from production tooling. The end comment was "There is a problem in the tooling design." B_____". I think you would or should look at your customers competance. Be careful.
Johnd