I am wondering if the below description is for "minimal engraved details" instead of "embossed details"..... For Silver, the minimum detail is determined by the casting process. Silver products are printed in wax, and then a liquid plaster is poured around them and solidifies into a mold. When liquid metal is poured into this mold, the pieces of plaster that create engraved details can break off if they are too small.
No, Shapeways has it correct. If you have a engraving that is too deep or too narrow then when you cast the investment around the wax part and then vaporize the wax away from the investment what you're left with is a thin sliver of investment protruding into the cavity of the mold wall exactly where the engraving was on the wax model. It is the opposite of what you're thinking. The embossings are actually quite safe because they become depressions into the investment walls so nothing can go wrong with the embossing unless there were embossings that were placed too close to one another. It doesn't just happen with just engravings it can happen wherever there is a depression or sharp inside corner anywhere on your model. This is very bad because when a piece of the investment breaks off it can contaminate all of the items being cast and cause them to be ruined. The main reason why is when you do polishing if there is any contaminants near the surface or any voids such as microscopic air bubbles solidified in place in the metal this can result in the surface not being able to be polished correctly.
Thank you UniverseBecoming for the detailed explanation. But I still have not figured it out. I am attaching a picture to point out my thought.
OH!!!! I SEE IT NOW!! GOOD CATCH! I didn't notice the word embossed the first time I looked and I didn't make the connection with the graphics or the subject matter of the guideline. But you did! Good going! Yep, they'll need to correct that.