Walk into any big-box store and nearly every plastic product you see was made by injection molding. It is fast, cheap at scale, and consistent. So why does StoneFyr use 3D printing instead? Because for coin storage, the things that matter most are precision, flexibility, and the ability to keep improving the design.
Injection molding works by forcing molten plastic into a steel mold. The mold itself costs $5,000 to $50,000 or more depending on complexity. Once it is machined, you are locked in. Want to change a dimension by half a millimeter? That is a new mold. Want to offer a different slab capacity? Another mold. Want to test a new lid mechanism? Another mold.
For coin slab storage, where the difference between a good fit and a bad fit is a fraction of a millimeter, that rigidity is a serious problem. NGC, PCGS, CAC, and ANACS holders each have their own width, height, and thickness, and the services revise their holders over the years. A slot that holds all of them without rattle and without binding takes iteration to get right. Getting it right on the first mold attempt is unlikely. Getting it right after test-fitting real slabs and adjusting the design dozens of times is what 3D printing allows.
Rapid iteration. We can adjust a channel profile in CAD, print a test piece in two hours, test-fit real slabs from every service, measure the clearances, tweak by 0.2mm, and print again the same day. Injection molding would need weeks of lead time for each change.
No tooling costs. Every dollar goes into materials and machine time, not steel molds. That is how we can offer 5, 10, 15, and 20-slab cases without needing to justify a separate mold for each. If collectors need a size we do not make, we can build it.
Material flexibility. Production parts print in PETG for strength and heat resistance, while prototypes can run in faster, cheaper material. Switching takes minutes, not a retooling cycle.
Small-batch viability. Injection molding only makes economic sense at thousands of units. 3D printing is cost-effective at any quantity, one case or one hundred. We can serve the coin collecting community without minimum order quantities or compromises driven by volume economics.
Every CoinConnex case and SlabGrid tray we ship is printed individually, and that means every single unit gets inspected. There is no bad batch from a worn mold and no gradual dimensional drift from thermal cycling in an injection press. Each print starts fresh from the same digital model.
We hold our printed parts to a tolerance of about ±0.2mm, and the slot dimensions come from calipers on actual holders from the major grading services, not from spec sheets.
Every product ships from our workshop in Plainfield, Illinois. We control the filament quality, the print settings, the post-processing, and the final inspection. When you order a CoinConnex case, we print it, check it, and ship it.
3D printing is not the cheapest way to make a plastic box. But we are not making boxes. We are making storage engineered around the actual dimensions of graded coin holders, and for that job it is the right manufacturing method.