MJP Printing — High-Resolution Wax 3D Printing for Casting
MJP Printing — High-Resolution Wax 3D Printing for Casting
MultiJet Printing of jewellery wax models at micron resolution for lost-wax casting
MJP printing — MultiJet Printing — is a wax-based 3D printing technology in which inkjet-style print heads deposit microdroplets of build wax and support wax in successive layers, building up a three-dimensional wax model directly from a CAD file. The technique produces highly detailed wax models suitable for direct burnout and investment casting in fine jewellery production, and is widely used in the high-end and bespoke jewellery sector for designs whose complexity would be difficult or impossible to achieve through conventional carved-wax or hand-fabrication routes.
The technology
MJP systems use multiple inkjet print heads mounted on a moving carriage to deposit two waxes simultaneously: a build wax that forms the part being printed, and a support wax (typically lower melting point than the build wax) that fills voids and overhangs to support the print during build. The waxes are heated to molten state in the print heads and deposited as fine droplets that solidify on contact with the cooler build platform.
Layer thicknesses on production-grade MJP machines reach as fine as 16 microns, producing surface finishes and feature resolutions superior to most other 3D printing technologies and approaching the quality of master-finished hand-carved waxes. After printing, the support wax is removed by gentle heating, leaving the build wax as a finished model ready for investment casting using standard lost-wax techniques.
The leading manufacturers
Solidscape, now part of Stratasys, is the historical leader in MJP technology for jewellery applications, with their machines (the T76, T-series, and successor models) widely used in jewellery production studios. Other manufacturers including 3D Systems and several specialised vendors have entered the space with comparable machines. The technology is mature and reliable, with established consumables, support, and operator-training infrastructure.
Applications
MJP printing is used for: complex bespoke designs that would be uneconomic to carve by hand; rapid prototyping for client review before commitment to final casting; production of multiple identical models for production runs; intricate filigree, lattice, and organic geometries that hand-carved wax cannot reliably produce; precision-fit components such as bezels machined to specific stone dimensions; and design iteration where multiple variants need to be produced and evaluated quickly.
The lost-wax casting process that follows MJP printing is the same as for hand-carved or commercially supplied waxes: investment in plaster, burnout of the wax, casting of the chosen alloy, and finishing of the cast piece. The MJP-produced wax burns out cleanly without ash residue, which is a significant practical advantage over some other 3D-printing technologies whose materials require special burnout cycles or leave residue that compromises casting quality.
Cost and adoption
MJP machines are capital equipment, with production models priced in the substantial five- to six-figure range. Per-piece printing costs once the machine is installed are modest, but the upfront capital and the requirement for skilled CAD operators mean that MJP printing is generally adopted by larger studios, bespoke houses, and specialised model-making services rather than by individual bench jewellers.
In the trade
Skyjems works with MJP-printed models for bespoke and complex production where the technology offers clear advantages over conventional approaches. The combination of CAD design, MJP printing, and traditional casting and finishing represents the contemporary state of the art in mid-to-upper-tier jewellery production. The bench-finishing skills and design sensibility remain entirely human; the model-production step is automated.