Bespoke OEM · Engineering Intake
From sketch to cast-ready 3D CAD in 48 hours
Telula Gray is a fine jewelry manufacturer in Yancheng, China. We turn a hand sketch, reference photo or rough model into production-grade 3D CAD — then cast, set and finish it in our own atelier. Send .STL, .3DM or .STEP files, or simply a drawing, and our CAD team returns a watertight, 3D-printable model within two working days.
1. Accepted 3D file formats
We accept parametric solids, mesh models and flat technical drawings. If you only have a photo, that is fine too — we will reconstruct the geometry and send you a preview before any metal is cut.
| Format | What it is | What we need from you | Mill tolerance |
|---|---|---|---|
| .STL | Triangulated mesh — the universal 3D-print language. | Binary STL exported at 0.01 mm chord tolerance. Meshes are re-surfaced before casting. | ±0.03 mm |
| .3DM | Rhino / NURBS surfaces — preferred for stone-set pieces. | Keep construction layers intact; include the pavilion/girdle reference curves. | ±0.02 mm |
| .STEP | Solid/parametric transfer from JewelCAD, Matrix, ZBrush or CAD. | AP214 or AP203; one solid per component, stated units in mm. | ±0.02 mm |
| .OBJ / .PLY | Scan data or sculpted organic shapes. | We will retopologise to a casting-grade surface (quoted per model). | ±0.05 mm |
| PDF / JPG | Hand sketch, technical drawing or reference photo. | Note ring size, stone dimensions and finished metal weight target. | Quoted on review |
2. The 48-hour CAD workflow
- Hour 0–4 — Intake & feasibility. Files are logged, checked for scale and watertightness, and a named engineer is assigned. We confirm stone calibrations and metal choice with you in writing.
- Hour 4–24 — Master model. Stone seats, prongs, galleries and hinge/pin tolerances are built to casting standards; the model is thickened for the alloy you selected.
- Hour 24–36 — Internal QA. Wall-thickness audit (minimum 0.8 mm on structural walls), draft-angle check, volume/weight report, render set from four angles.
- Hour 36–48 — Delivery. You receive the .3DM/.STL/.STEP package plus a PDF spec sheet with calculated gold weight. One round of revisions is included.
- After approval. Resin print → rubber mould or direct investment → vacuum casting → setting → polishing. Sample in 10–15 working days.
3. Sample MOQ & production MOQ
We exist for brands that need to validate a design before committing capital. That is why our sample run starts at 1–2 pieces per SKU — not 50.
- Sample / prototype: 1–2 pcs per design, in your chosen karat and stone grade.
- Repeat sample: same model in a second metal or stone combination — no new CAD charge.
- Bulk production: 20–30 pcs per SKU per size-run (mixed sizes count as one run).
- Bespoke one-off: single-piece commissions accepted for engagement and couture work.
4. Bilateral Mutual NDA
Every bespoke project starts under a bilateral (mutual) non-disclosure agreement — it protects your design IP and our process documentation equally. Tick the NDA box in the form below and we will send a signable PDF within one business day; e-signature is accepted.
- Term: 3 years from signature, surviving termination.
- Scope: drawings, CAD files, stone layouts, brand plans, pricing.
- No use of your designs in our portfolio or marketing without written approval.
- Your tooling, moulds and masters remain your property and are stored in a locked vault.
5. Gold weight calculation
Quotes are built on real metal weight, not guesswork. Our engineers read the model volume from the CAD kernel and convert it with the alloy density:
| Alloy | Density (g/cm³) | Typical casting loss |
|---|---|---|
| 18K yellow gold | 15.5 | 10–12% |
| 18K white gold | 15.2 | 11–13% |
| 14K yellow gold | 13.4 | 10–12% |
| 10K gold | 11.6 | 9–11% |
| 9K gold | 11.2 | 9–11% |
| 950 platinum | 20.7 | 3–5% |
Worked example — 18K solitaire ring: CAD volume 420 mm³ → 420 × 15.5 ÷ 1000 = 6.51 g → × 1.12 (12% sprue and polishing loss) = 7.29 g of 18K gold quoted. Diamond weight is quoted separately from the calibrated stone list.
Final invoiced weight is reconciled against the cast piece; any difference above 3% is credited or re-quoted.
6. Project inquiry form
Tell us what you are building. Attach or paste a link to your files (WeTransfer, Google Drive, Dropbox) — nothing is shared outside the project team.