CAD Design Checklist Before Sending the File to Your Manufacturer
A CAD file that looks perfect on screen can still fail at the bench. The render doesn’t know about wall thickness, stone security, or casting tolerances — only a proper technical review catches those before they become an expensive problem. Here’s what to check before any file leaves your desk.
1. Confirm the Mesh Is Watertight
Before anything else, the model needs to be a single, sealed solid — no open edges, gaps, or self-intersecting surfaces. An open mesh can pass a visual check and still fail in casting or 3D printing, producing incomplete or distorted results. Run the file through a mesh-repair check (most CAD software and slicing tools include one) rather than assuming a clean-looking render means a clean file.
2. Verify Wall Thickness Throughout
Thin sections are the single most common cause of casting failure. As a general guideline, structural walls and bands should sit at roughly 0.8–1.2 mm minimum depending on the metal, with thinner allowances only for small decorative details — never for load-bearing areas like a ring shank or prong base. Check every section of the model, not just the areas that look thin to the eye; a design can hide thin spots in curves or transitions that aren’t obvious from a standard render angle.
3. Check Stone Seats Against Actual Measurements
If the piece is built around a specific stone, confirm the seat dimensions match the stone’s real measurements — not an approximate size. This matters especially for graded stones with a GIA or IGI report, where even a fraction of a millimeter of mismatch can mean a stone that sits loose or doesn’t seat properly.
4. Review Prong and Detail Thickness
Prongs and thin decorative elements need enough mass to survive casting and daily wear without being so bulky they look clumsy. Confirm seat depth is sufficient to hold the stone securely, and check that any transition from thick to thin sections is gradual rather than abrupt — sudden thickness changes concentrate stress and are a common crack point.
5. Confirm Correct Scale and Units
One of the most common — and most avoidable — errors in file handoff is a unit mismatch (millimeters exported as inches, or vice versa), which silently produces a piece that’s wildly the wrong size. Double-check the file’s units and actual dimensions before export, not just the ring size or stated measurements in your notes.
6. Check for Undercuts and Draft Angles
Certain geometries are difficult or impossible to release cleanly from a casting mold without a slight taper (draft angle) built in. If your design has parallel walls or trapped geometry, flag it — your manufacturer may need to adjust the design or split it into components to produce it successfully.
7. Smooth Sharp Edges and Snag Points
Any edge that will sit against skin or clothing should be checked for comfort and durability, not just appearance. Sharp internal edges are a common source of both discomfort and long-term wear damage.
8. Export in the Right Format
Most manufacturers and casters expect an STL file for production, alongside the original editable file (such as 3DM) for future reference or revisions. Confirm with your specific manufacturer which formats and export settings they require before sending — some casting houses have specific resolution or tolerance preferences.
Why This Step Is Worth the Time
Skipping this review doesn’t save time — it just moves the cost of catching a problem from your desk to the bench, where fixing it is slower and more expensive. A five-minute check against this list before export is consistently cheaper than a failed casting or a client waiting on a redo. This is also exactly why understanding wall thickness and prong design in more depth pays off, and why preparing a file properly for 3D printing is its own step worth getting right.
FAQs
Can my manufacturer catch these issues for me? Many will flag obvious problems, but a thorough review on your end catches issues earlier and avoids delays waiting on manufacturer feedback and file resubmission.
What’s the most common mistake designers make before sending files? Unit/scale errors and thin wall sections are by far the most frequent — both are easy to miss visually and easy to check for directly.
Do I need special software to check for these issues? Most CAD programs include basic mesh-checking tools; dedicated mesh-repair software can catch issues a quick visual review misses.
Should I always include the original CAD file, not just the STL? Yes — keeping the editable file (3DM or equivalent) alongside the STL makes future revisions far easier than starting over from the print-ready file alone.