Resin: a liquid material for SLA and similar printers

How it works

A photopolymer is a mixture that sets when lit with the right wavelength. The printer cures it layer by layer, either with a laser (SLA, which Wikipedia also covers) or a whole layer at once through a matrix (MSLA, DLP). The layers are thin, down to 0.05 mm, so the surface is smooth and the detail fine.

After printing, the part has to be washed in alcohol and post-cured under a UV lamp. Liquid resin irritates the skin and the fumes are unhealthy, so you work with gloves and ventilation.

Strengths and weaknesses

Resin produces detailed jewellery, figurines and dental models. Typical standard resins are brittle, though, and worse than PETG for load and drops. They cost more, and the waste is a problem, because uncured residue must not be poured into the waste. Some engineering resins are tougher, but they are expensive.

What we do

We do not print resin. We work with FDM, that is, melting a strand of PLA and PETG with a 0.4 mm nozzle and a 0.2 mm layer height. For ordinary brackets, small boxes, covers and spare parts that is quite enough, and the parts are stronger than ones from ordinary resin. Very fine detail, such as very thin structures or tiny figurines, cannot be printed that way.

The closest alternative for a smoother surface is PLA, which can then be sanded and painted, but you do that yourself (sanding). Want resin printing? Write to jakub.novak@boostello.com. We do not promise to print it.

When resin is better and when FDM

Resin wins on very small, detailed parts: figurines, jewellery, dental models. FDM wins on larger functional parts: brackets, covers, tools, spare parts where strength matters, and on larger runs. A resin part is more likely to snap on impact, while an FDM part is more likely to bend.

Price speaks too: FDM has cheap material (PLA €8 per kg, PETG €9 per kg) and a bigger build volume. The largest part with us is 246 × 246 × 256 mm. Desktop resin printers have a far smaller build volume.