Checklist
What manufacturing-ready means
A render can be finished while the model is not. This is the list a CAD supervisor walks before a file is called cast-ready. The numbers live with each caster, not here.
- 01
Closed, watertight solid
The metal body is one closed solid. No naked edges, no non-manifold edges, normals facing out. If two parts only look joined, Boolean them. A group is not a union.
- 02
Only metal in the print
Stones, cutters, reference curves and construction surfaces stay off the mesh you send to print, unless the caster has asked for stones left in the file. Stuller, for example, wants stones kept in a 3dm.
- 03
Wall and prong thickness
Measure the thinnest metal that has to survive printing, investing, casting and the file. Compare it with that caster’s published minimum. Prongs and claws are usually thinner than the shank, and they still have to survive setting. If the caster’s page on this site is blank, ask them. Do not copy another house’s number.
- 04
Shank
Check width and thickness at the bottom, where it is often thinnest, and where a sprue will be cut off. Leave enough metal that filing the sprue does not flatten the profile. Some houses ask for a little extra metal at the sprue join for that reason.
- 05
Sprue points
Feed the thick sections. A thin sprue into a heavy head is a common porosity. If the caster wants gates, sprues or a reservoir modelled in the file, build them to the diameters they publish. If they would rather sprue it themselves, leave the metal clean and say so.
- 06
Shrinkage and finishing allowance
Wax, metal and polishing each move the size. Ask whether the file should be at finished size or already scaled. Record the allowance they give you for metal removed at the bench. A finishing figure from one alloy does not travel to another.
- 07
Stone seats and clearances
Seats match the stones you were given, not a generic cutter. Check girdle coverage, the culet’s clearance from the finger, and that a pilot hole is not deeper than the caster can cast. Leave room for a hallmark if the piece needs one.
- 08
File format
STL is the mesh most printers take. 3DM is the Rhino solid many jewellery houses still want, because it can be edited. Send the format that house names. If they accept both, send the 3dm as the master and an STL that has been checked for holes.
- 09
Edges, text and holes
Knife edges and hairline lettering wash out or fill in. Round sharp corners. Keep engraved or raised type inside the widths, heights and draft the caster publishes. Holes need a diameter they can cast, and should not be deeper than they are wide unless you have been told otherwise.
- 10
Send the sheet with the file
Name the caster, the alloy, the finger size, and the stones. A manufacturing-ready file is one their floor can run without ringing you about a missing seat or a 0.3 mm wall.