Why we bought a Formlabs Form 4

Resin printing is the most frustrating corner of this industry. The parts are the best you can make on a printer — smooth, sharp, accurate, no layer lines — and the machines that make them have traditionally been the hardest to run as a business. This month we replaced our consumer-grade resin printer with a Formlabs Form 4, and I want to explain why, because the reasoning says a lot about how we think about the service we sell.

The problem with resin machines

Consumer resin printers are remarkable value for hobbyists, and I have nothing bad to say about anyone printing miniatures on one at home. Running one commercially is a different question. Resin is messy and every material behaves differently, so each new resin means tuning, test prints and waste. Failures announce themselves hours into a print, usually as a part half-fused to the film. And most hobbyist resins ship with no meaningful datasheet, which means you can't honestly tell a customer what their part will do under load, heat or sunlight — you can only tell them what it looks like.

Our answer for a long time was to keep the SLA offer deliberately narrow: one proven resin, one colour, priced honestly. That kept quality consistent, but it meant turning away the most interesting work — clear optical parts, flexible grips, castable jewellery patterns, high-temperature tooling. People asked for those things at the quote stage and we couldn't sell them.

What the Form 4 is

The Form 4 is Formlabs' current professional SLA platform — the same machine you'll find in serious product studios and engineering teams. Instead of tracing each layer with a laser, it cures entire layers at once with a masked light engine, which makes it faster and more repeatable than older SLA designs. More importantly for us, it turns resin printing from a craft into a process: resins come in cartridges with published datasheets, settings are validated by Formlabs rather than tuned by hand, and every part goes through a controlled wash and UV cure before it leaves the workshop.

What changes for your parts

The practical difference is choice. Our SLA printing service now quotes fifteen Formlabs resins online, instantly: standard black for presentation models, Tough 1500 and Tough 2000 for snap-fits and functional prototypes, glass-filled Rigid 4000 and 10K for parts that must not flex, Durable for living hinges, Flexible 50A and 80A plus a true Silicone 40A for soft parts, High Temp for tooling, Flame Retardant and ESD for electronics and transport work, Castable Wax for jewellery patterns, Clear Cast for optically clear parts, and a draft-speed Fast Model resin for early iterations.

We keep the most-used resins in stock and order the specialist ones in per job — the quote tool tells you upfront if a resin is special-order and exactly what that adds, before you pay anything. Every resin is priced on its actual cost, every part ships washed and cured, and every material has a datasheet I can send you. SLA prints start from around £12 and most orders still dispatch in 1–3 working days.

Resin printing finally works the way the rest of our workshop works: upload a file, pick a material, get a real price in seconds, and know exactly what you'll receive. That's what the Form 4 bought us — not a shinier machine, but the ability to say yes to the jobs we used to turn away.