The project that seemed perfect — until it reached production
Every jeweler or designer has had that experience: the design looks beautiful in the software, the client approves, you invest in the mold or printing — and in production, something goes wrong. The piece comes out with bubbles, the mold won't release, the casting fails, the detail disappears. A guaranteed loss.
At MS Soluções para Joalheria, with over 30 years of analyzing and producing technical projects for jewelry, we have identified the same 7 errors recurring in projects by designers of all levels — from beginners to the experienced. Knowing them is the first step to avoiding them.
Error 1: Walls too thin for the chosen process
Walls below 0.8mm for direct casting and below 1.2mm for rubber molds are the most frequent cause of failures. The wax doesn't fill, the metal doesn't flow, and the piece comes out with missing material or fractures during finishing.
Solution: Always verify the minimum thickness within the software itself before exporting. In Rhinoceros, use the 'AnalyzeDir' command + mesh inspection. In ZBrush, use 'Check Geometry'. Define the actual thickness while still in the 3D model, not after.
Error 2: Closed geometries without a vent channel
Totally closed cavities trap gas during casting. The result is internal porosity — bubbles that appear during polishing or, worse, only after the sale when the piece fractures during use.
Solution: Every closed volume needs a gas escape channel at least 0.5mm in diameter, positioned at the highest point of the geometry during casting. If the design does not allow for a channel, switch to direct casting with correct positioning on the tree.
Error 3: Unplanned undercuts for the mold
An undercut is any area that prevents mold release. An unplanned undercut forces the rubber, tears the mold during the first releases, and deforms the injected wax. The result: a prematurely unusable mold and pieces that are out of specification.
Solution: When designing for a mold, think in terms of 'parting lines' — all surfaces must allow for separation on at least two planes. If the design requires deep undercuts, plan for inserts (removable mold pieces) or switch to direct casting.
Error 4: Surface details below the process resolution
Text engraved with 0.2mm letters, carbon fiber textures, micrometric fish scales — these are beautiful details in the render that disappear in conventional rubber molds or mass casting.
Solution: For details below 0.3mm, use direct casting from high-resolution 3D printing (SLA printers with 25-micron resolution). For molds, keep details above 0.4mm in depth to ensure faithful reproduction.
Error 5: Jump rings, clasps, and mounting elements not integrated
Designing a pendant's jump ring separately from the body of the piece creates a solder joint that frequently fractures during use — especially in everyday pieces like earrings and bracelets. Furthermore, it adds a bench stage that increases cost and lead time.
Solution: Integrate the jump ring into the pendant's 3D design. Design the earring post as part of the piece's body. Include the clasp system in the bracelet design itself. This eliminates steps, reduces costs, and increases the jewelry's durability in use.
Error 6: Incorrect proportions for commercial ring sizes
A ring designed with a 17mm inner diameter might seem standard — but ring sizes vary between systems (Brazilian, American, European) and between models. A design that does not account for adjustment tolerances forces the client to perform expensive resizing or makes the piece unsellable to a large part of the public.
Solution: Always design with reference to the measurement system of your primary market. For Brazil, use the national system (sizes 10 to 30). For Europe, use the ISO system (inner diameter in mm). Include a clear indication of the size and the system adopted in the project.
Error 7: Exporting STL with low mesh resolution
An STL file with few triangles generates faceted surfaces — visible planes where smooth curves should exist. This problem appears clearly on the printed object and, after casting, requires hours at the bench for manual correction.
Solution: When exporting the STL, use at least a 0.01mm edge deviation tolerance and 0.01mm angular tolerance. In Rhinoceros, this is equivalent to the 'High' setting in the export dialog box. The file will be larger, but the surface will be smooth and the finish will be superior.
Conclusion: proper design is profitable production
Avoiding these 7 errors puts any jewelry project on a truly professional level. The difference between a project that works and one that generates rework is almost always in these technical details that seem small — but cost time, money, and reputation.
At MS Soluções para Joalheria, every project undergoes a complete technical analysis before production. Request an analysis of your project and avoid rework.
See also: 3D Design: mold or direct casting? | How to prepare an STL file for mass production
Want to master these concepts in practice? Check out our Complete Course on Professional Casting and Molding or follow us on Instagram @ms.solucoesparajoalheria.
