Parts of a Resin Printer

How the parts work together

Most hobby resin printers are MSLA (masked stereolithography, also called LCD printers). The light sits underneath. For each layer, the LCD screen turns into a stencil of that layer's shape, the light shines up through it and through the clear film in the bottom of the vat, and the thin layer of resin between the film and the part hardens. Then, as Formlabs describes its own machines, the build platform rises and the Z axis peels the new layer away from the bottom of the tank. The platform lowers again, fresh resin flows in, and the next layer is cured. The part grows upside down, hanging from the platform.

The parts, one by one

Part	What it does	What damages it
Build platform	The plate the print hangs from. Its underside is where the first layers cure.	Cured leftovers. Prusa notes surface scratches on the platform do not affect print quality.
Vat (resin tank)	Holds the liquid resin during the print.	Cured flakes or a failed print left inside, which press into the film and screen.
Film (FEP or similar)	The clear, flexible bottom of the vat. Light passes through it, and its flexibility lets each layer peel off.	Scratches, dents and holes. Prusa says to replace a damaged film right away.
LCD screen	Masks the light into the shape of each layer.	Scratches from sharp tools or rough cloths; resin leaking from a damaged film.
Light source	An array of UV LEDs under the screen.	Dust. Prusa notes dust can build up under the display and on the reflector.
Z axis (tower)	Raises and lowers the platform on a lead screw.	Noise or rough travel; Prusa says its tower needs little maintenance beyond occasional lubrication.
Lid or cover	Blocks outside UV light and UV from the printer.	Solvents. Prusa says not to clean its lid with alcohol, acetone or chlorine.

Some printers add other parts. Prusa's SL1S, for example, has a tilt mechanism under the tank and a carbon filter behind a small rear door. Check your printer's manual for what yours has.

The film: the part you will replace most

The film is the thinnest, most stressed part of the printer. Every layer is cured against it and pulled off it. Prusa's guidance for its SL1 and SL1S printers:

• Inspect the film before and after each print.
• Replace a scratched, dented or holed film right away, because a hole lets resin spill onto the screen and into the printer.
• Clean a cloudy film with warm water and dish soap, and never with isopropyl alcohol.

Other makers' films and cleaning advice differ; follow the guide for your vat. When a print sticks to the film instead of the platform, see Resin Print Stuck to the Film, and for routine care, Resin Vat and Film Care.

The screen and light

The LCD does not cure anything by itself; it only blocks light where the layer should stay liquid. Prusa says to check its exposure screen for smudges, stains, scratches and cracks before each print, to clean it with a damp cloth or screen spray and soft paper towels, and never to touch it with metal spatulas, knives or screwdrivers. Prusa also says to empty the tank after each print and to clean the platform thoroughly, because leftover cured supports or pads can damage the tank bottom or the display.

Light, heat and where the printer sits

Resin cures in UV light, including sunlight. Prusa says to keep the lid closed during printing and not to place the printer by a window, because sunlight can cure resin in the tank. Formlabs advises storing resin away from direct sunlight in a dry, cool, well-ventilated area. Setup and room conditions are in Setting Up a Resin Printer.

Anything resin touches

The platform, vat, film, scraper and the printed part all carry uncured resin. Formlabs' Grey Resin SDS, as one example, classes the resin as causing serious eye irritation and possible allergic skin reactions and as toxic to aquatic life; it calls for chemical resistant gloves, safety glasses or goggles and adequate ventilation, and says not to discharge it into public wastewater. Formlabs advises nitrile or neoprene gloves, not latex, and washing skin with soap and water, never with alcohol or solvents.

• Read the SDS for the exact resin you use and follow its handling, protection and disposal sections. Water-washable resin is not harmless and its wash water is not drain-safe.
• Clean the platform over a tray so drips do not reach the printer's tilt mechanism or bench. Prusa cleans its platform with isopropyl alcohol and says to dry it thoroughly.
• Pour leftover resin back through the maker's recommended route; Prusa suggests a separate bottle rather than mixing used with new.

Full routines: Resin Protective Equipment, Washing and Curing Resin Prints and Resin Waste Disposal. Exposure settings, the main print setting on these machines, are in Resin Exposure.