Setting Up a Safe Workspace

Start with your printer's own safety chapter

Every printer maker publishes safety instructions for its machine, usually in the handbook or quick-start guide. Read them before the first print; they cover the hazards specific to that design, such as hot and moving parts. Prusa's current printers also switch off all heating if the printer sits idle and heated for more than 30 minutes Maker spec. That only acts when the printer is idle, not during a print, so it is no reason to leave a print unattended. Protections like that reduce risk; they do not replace your attention.

Never modify mains wiring, heaters, thermistors or thermal protection to fix a problem. Those are service jobs for the maker or a qualified technician. See Fire and Electrical Safety.

Placing the printer

• A stable, level surface that will not shake.
• Clear space around it for airflow, cable access and the moving bed or head. Check your printer's handbook for the clearance it asks for.
• Away from food, drink and sleeping areas. Formlabs says not to eat, drink or smoke in the printing work area.
• Resin and solvents locked away. eSUN's resin SDS, for example, says to store the product locked up.

FDM: particles, vapors and air

Melting plastic releases ultrafine particles (UFPs, far too small to see) and volatile organic compounds (VOCs). Ultimaker's white paper on emissions states that all the polymers it tested emit UFPs, that PLA emitted the lowest concentration in its tests, and that higher-temperature engineering materials such as polycarbonate emitted more. Ultimaker lists seven factors that decide how much of this ends up in the air you breathe:

1. The room's volume
2. The room's air exchange rate
3. How many printers run at once
4. Which materials you print
5. How long you print
6. How close you sit to the printer
7. Other emission sources in the room

Ultimaker's safe-use statement for its own printers and materials assumes one printer in a room of 30.6 m³ with an air exchange rate of 1.8 per hour Maker spec. That is a condition for Ultimaker's products, not a universal rule, but it shows the shape of the problem: a small, closed room with several printers running engineering materials is the worst case, and Ultimaker recommends extra measures such as filtration or dedicated ventilation for small rooms, poor ventilation, multiple printers and large amounts of engineering materials.

Practical steps that follow from those factors: print in a room with real air exchange, do not sit next to the printer for hours, and check the filament maker's SDS for the materials you use. In Ultimaker's tests, ABS had the highest total VOC emission rate of the materials tested; see ABS and ASA and FDM Emissions and Ventilation.

Resin: contain it, protect yourself

Liquid photopolymer resin is a skin sensitizer and an eye irritant. Formlabs' SDS for one of its standard resins lists "May cause an allergic skin reaction", "Causes serious eye irritation" and "Toxic to aquatic life with long lasting effects", and requires gloves, protective clothing and eye protection. Set up the resin area like this:

• Ventilation. The same SDS says to use the resin only with adequate ventilation and to avoid breathing its vapor or mist.
• A wipeable, protected surface that can catch drips. Formlabs advises washing resin spills outside the printer with soap and water, and spot-testing any solvent on the surface first.
• Gloves and eye protection within reach before you open a bottle. Formlabs specifies nitrile or neoprene gloves, not latex.
• Soap and water nearby. Formlabs says to wash resin off skin with soap and water, and never with alcohol, hand sanitizer or other solvents.
• Storage in the original closed container, cool, dry, well ventilated and out of direct sunlight, as the SDS describes. Formlabs gives 10 to 25 °C for best shelf life of its resins Maker spec.
• Waste kept in labeled containers. The Formlabs SDS says not to discharge the resin into public wastewater or surface waters, and Formlabs says liquid, dissolved or partially cured resin and anything contaminated with it must be disposed of according to environmental regulations. See Resin Waste and Disposal.

Water-washable resin is not harmless

"Water washable" describes how the print is cleaned, not how safe the resin is. eSUN's SDS for its water washable resin lists "May cause an allergic skin reaction" and eye irritation, and calls for protective gloves, clothing and eye and face protection. It also says to avoid release to the environment and recommends curing the material before disposal according to local regulations. Rinse water from washing these prints contains uncured resin: never pour it down the drain. Handle it like any other resin waste, following your resin's SDS and your local rules.

Before the first print, check

1. The maker's safety chapter is read.
2. The printer sits on a stable surface with the clearance its handbook asks for.
3. The room has air exchange you can count on.
4. For resin: gloves, eye protection, paper towels, soap and water and a labeled waste container are set out before the bottle is opened, and you have read that resin's SDS.

Protective gear for resin is covered in Resin Protective Equipment.