Resin Printing Safety and Handling

Resin Printing Safety and Handling

Resin 3D printing has exploded in popularity in recent years. The technology allows for incredibly detailed prints with smooth surfaces. However, resin printing does come with some safety considerations. When handled properly, resin 3D printing can be done safely. This comprehensive guide will provide an overview of resin printing, discuss the potential hazards, and offer best practices for safe resin use, storage, and disposal.

An Introduction to Resin 3D Printing

Resin-based 3D printers utilize photopolymer resins which harden and cure when exposed to UV light. This allows the resin to be precisely solidified layer-by-layer to create smooth, high-detail prints.

There are two main types of UV resin printers:

  • Stereolithography (SLA) – A laser precisely cures resin in a vat layer-by-layer. The build platform lifts out of the vat allowing each new layer to be cured.
  • Digital Light Processing (DLP) – Uses a projector screen to flash and cure full layers at once instead of tracing with a laser.

Both produce high-quality prints by curing liquid resin into hardened plastic. The resin is contained in a reservoir and slowly hardens as light is applied. But this emerging technology comes with some potential health and safety concerns that printers should be aware of.

Understanding Resin Hazards

Most resin used in 3D printing is photopolymer resin. This type of resin cures and hardens when exposed to UV light. However, in its liquid state, resin can pose some health hazards (1):

  • Skin irritation – Resin is a skin irritant and can cause redness, itching, and allergic reactions in those with sensitivities. Isocyanates and acrylates are common allergens found in resin.
  • Eye irritation – Resin droplets or fumes can cause eye irritation if proper eye protection is not worn. This can potentially lead to conjunctivitis.
  • Respiratory irritation – Heated resin can produce fumes and VOC emissions that cause throat and airway irritation when inhaled, especially in poorly ventilated rooms.
  • Toxicity concerns – Some resins contain trace amounts of toxic compounds and monomers like formaldehyde, isocyanates, and bisphenol A. These have been linked to organ damage and reproductive harm with prolonged or excessive exposure.
  • VOC emissions – All resins emit small amounts of volatile organic compounds (VOCs) which can be hazardous depending on the type of resin (2).

While hardened resin prints themselves are generally considered non-toxic, exposure to liquid resin in its uncured state does pose potential health risks worth understanding and protecting against.

Safe Resin Printer Setup

When setting up your resin 3D printer, there are important safety steps to take:

Select an Appropriate Location

  • Place printer in a well-ventilated room – Ensure good airflow to reduce concentration of VOC fumes. Avoid enclosed spaces like cabinets.
  • Set up near an exterior window – Having fresh outdoor air circulation is ideal for dispersing fumes.
  • Avoid high temperatures – Heat accelerates VOC emissions so avoid hot rooms or direct sunlight.
  • Keep away from food prep areas – Don’t place printer on kitchen counters or anywhere near food.

Use Personnel Protective Equipment

  • Wear nitrile gloves when handling resin and prints to avoid skin irritation (3). Latex gloves can degrade with resin contact.
  • Put on safety goggles to protect eyes from droplets, splashes, and fumes.
  • Use a respirator mask when working near printer and resin to prevent breathing in VOC gases.

Monitor Resin Access Points

  • Keep resin vat covered when not printing to contain fumes.
  • Store resin in sealed containers to prevent leaks or emissions.
  • Place printer on spill mat in case of leaks. Clean thoroughly with isopropyl alcohol.

Adjust Machine Settings

  • Keep resin heated as low as possible to reduce VOC emissions.
  • Use moderate fan speeds to extract fumes but not stir up excess VOCs.

Wash Hands Thoroughly

  • Always wash hands with soap and water after handling printer, resin, and prints. This prevents inadvertent skin contact and spread of resin residue.

By carefully selecting the printer’s location, wearing proper PPE, and following safe setup procedures, resin 3D printer operation can be done more securely.

Recommended Safe Resin Handling Practices

When preparing prints, cleaning prints, and disposing of resin, follow these safe handling guidelines:

Mixing Resin

  • Wear nitrile gloves, goggles, and respirator mask when handling resin
  • Mix resin in well-ventilated area to limit VOC concentration
  • Avoid contact with skin – wear long sleeves and pants
  • Mix smoothers and dyes fully to avoid uneven curing
  • Replace container lids promptly to minimize fumes

Removing Prints

  • Give printed parts time to fully cure before handling
  • Use nitrile gloves to avoid skin irritation
  • Carefully detach prints from build plate to prevent damage
  • Rinse firstly with isopropyl alcohol to clean off excess resin

Washing Prints

  • Submerge prints in alcohol bath and gently scrub to dissolve resin
  • Use soft toothbrush to carefully remove residual resin
  • Rinse with clean alcohol bath 2-3 times until clear
  • Allow to fully air dry before further handling

Disposing of Resin and Filters

  • Do not pour resin down household or workshop drains
  • Cure waste resin safely under UV light in contained environment
  • Allow resin to fully harden before disposing as regular solid trash
  • Avoid emptying liquid resin in open trash containers – this can spill and leak hazardous materials
  • Discard used printer filters in accordance with local guidelines for safe resin waste disposal

Storage and Transportation

  • Store resin containers sealed and upright to prevent leaks
  • Keep resin bottles out of direct sunlight to avoid excessive heating
  • Place materials on stable surfaces and avoid dropping or heavy impacts
  • When transporting, seal containers and isolate from passengers

By adhering to safe resin handling techniques, the risks of exposure can be substantially reduced.

Recommended Resin Storage Protocol

Proper resin storage helps prevent spills, contamination, and keeps resin usable longer:

  • Store resin in cool conditions – Ideal storage temperature is below 30°C/86°F away from heat sources that could cause warming. Excessive heat can degrade resin over time. (4)
  • Avoid sunlight – Direct sunlight and UV exposure leads to premature curing in resin bottles. Keep resin in dark, opaque containers.
  • Seal bottles tightly – Replace bottle caps securely after each use to prevent leaks, spills, and limit VOC emissions.
  • Limit oxygen exposure – Oxygen can inhibit resin curing, so minimize air in bottles. An inert gas spray can help remove oxygen prior to sealing.
  • Keep bottles upright – Store resin bottles vertically to avoid leaks from accidental tipping. Never store resin bottles sideways or upside down.
  • Clean exteriors – Wipe down outside of resin bottles to avoid sticky messes and handling hazards. Use isopropyl alcohol to dissolve residue.
  • Use spill trays – Keep bottles in plastic bins or on trays to contain any leaks and prevent surface contamination.
  • Watch expiration dates – Most resins have 6-12 month shelf life. Mark dates on bottles and use oldest resin first.

Proper resin storage extends shelf life, preserves print quality, and prevents accidents. Always handle resin carefully and with appropriate PPE even during storage activities.

Recommended Resin Printing Procedures

When preparing to print using photopolymer resin, following best practices can help reduce safety risks:

Before Printing

  • Ensure printer is firmly situated on a stable, level surface not prone to impacts or vibrations.
  • Check resin levels and refill if needed – top off vat and reserve bottles.
  • Inspect resin bottle caps for leaks or cracks – replace if damaged.
  • Examine FEP film for rips or holes and change if not pristine.
  • Make sure there is sufficient isopropyl alcohol and materials for post-print wash.
  • Have nitrile gloves, goggles, mask, and spill clean-up supplies available.
  • Turn on fans – use exhaust fan directed out window if possible.
  • Shake resin bottle vigorously for 30-60 seconds to thoroughly mix.
  • Carefully fill resin vat, avoiding splashing.

Starting Print

  • Double check build plate is leveled properly before beginning.
  • Gradually lower build plate into resin vat while checking for clearance issues.
  • Initiate print once plate is correctly positioned.
  • Briefly remain nearby to ensure first layers adhere properly.

During Printing

  • Periodically check printer status, resin levels, and print progress.
  • Top up resin vat if needed – pausing print to avoid spills.
  • If leaks occur, stop print immediately and clean thoroughly with isopropyl alcohol.
  • Avoid directly inhaling fumes – take breaks in fresh air if needed.

After Printing

  • Allow print to finish curing under UV light for recommended time.
  • Remove build plate and wash thoroughly in alcohol bath.
  • Detach print from plate using plastic tools – avoid damaging print.
  • Rinse print multiple times in clean alcohol baths.
  • Let print dry fully before further handling and post-curing.
  • Seal and store any remaining resin in designated containers.
  • Dispose of any resin-contaminated materials appropriately.
  • Clean resin vat, build plate, and tools.

Carefully following resin printing best practices reduces safety hazards and results in successful prints. Always take steps to minimize contact and contamination when working with photopolymer resin.

Using Resin Safely

While resin 3D printing does necessitate caution, it can be performed at home safely with consistent adherence to recommended guidelines:

General Precautions

  • Always use personal protective equipment – gloves, goggles, and respirator mask
  • Work in well-ventilated rooms to allow fumes to disperse
  • Avoid skin contact by covering arms, hands, legs, and feet
  • Never touch eyes while using resin – wash hands thoroughly before and after
  • Follow usage instructions closely and monitor equipment
  • Store resin securely away from heat, light, vibration, and children/pets

Engineering Controls

  • Use exhaust fans vented outside to remove fumes
  • Situate printer away from high foot traffic areas
  • Place printer enclosure in ventilated area or use external vents
  • Use screens or shields to block UV light leakage

Administrative Controls

  • Post warning signs indicating risks
  • Label resin bottles clearly with contents and hazards
  • Develop standard operating procedures for safe use
  • Limit resin printing time to reduce exposure
  • Schedule maintenance when printer is not actively running

Personal Behavior

  • Remain alert and exercise caution when handling resin
  • Never rush or take shortcuts – follow safety steps fully
  • Keep flammables like alcohol away from ignition sources
  • Take breaks from printing to get fresh air
  • Wash up immediately after handling printer or resin

With smart precautions and consistent safe behavior, resin 3D printing can be an enjoyable hobby. But always exercise caution and minimize risks when using these materials.

Disposing of Resin Safely

Like many chemicals, resin requires special care when disposing. Take steps to avoid contamination and harm:

Hardening Liquid Resin

  • Never pour resin down household or workshop drains. It can pollute water and sewage systems.
  • Cure excess liquid resin first before disposal by containing and exposing to UV light. This solidifies it into a hardened plastic.
  • Use disposable containers lined with plastic bags for easy resin removal. Glass works well for curing.
  • Allow resin to fully harden over 24-48 hours under UV lamps before handling. Test hardness before disposal.

Disposing Solid Resin

  • Once fully cured, resin can be disposed as regular municipal solid waste.
  • Remove hardened resin from containers and discard in household trash in sealed bags.
  • Recycle any containers cleaned of resin residue according to local guidelines.

Used Filters and Contaminated Materials

  • Resin-contaminated items like gloves, wipes, and filters may require special hazardous material disposal.
  • Consult local environmental waste authority about proper categorized disposal.
  • Avoid emptying liquid resin residue in open trash bins where leaks could still occur.

Community Options

  • Some localities offer resin waste disposal days or locations to drop off 3D printing refuse.
  • Schools and makerspaces may collect community resin waste for combined proper disposal.

Always call ahead before attempting to dispose of any liquid resin waste at handling facilities. Allow resin to fully cure first before discarding to avoid contamination.

Ensuring Proper Resin Ventilation

Ventilation helps control resin fumes, but different methods have pros and cons:

No VentilationNo fans or airflowLower noiseIncreased fume exposure
Passive VentilationOpen windows or ventsImproves some air exchangeLimited circulation
Extraction FansRemoves air from roomMore effective at reducing fumesMust duct air outside
Enclosure ExhaustVented enclosure for printerCaptures emissions at sourceRequires ducting, small build volume
Air FiltrationFilters resin particlesReduce particle concentrationLess effective for gases
Carbon AbsorptionAbsorbs VOCsHelpful for gasesRequires filter replacement
Laminar FlowDirected air circulationContained airflowHigh equipment costs

recommended approach:

  • Use an enclosure vented to outside to capture emissions
  • Supplement with room ventilation fan in window to exchange room air
  • Have PPE and respirator mask for additional protection

Proper ventilation is key to reducing resin VOC exposure during and after printing. Ongoing monitoring should be conducted to verify ventilation effectiveness.

Final Thoughts

Resin 3D printing offers exciting new design options for makers and engineers. But as with any emerging technology, precautions are needed to use it safely. This guide provides research-backed recommendations on handling, storing, and disposing of photopolymer resin.

While resin printers are relatively safe when protocols are followed, there are inherent hazards to the materials involved. Emissions, spills, and skin contact should always be minimized. Work intentionally to reduce risk.

For those eager to get started with resin 3D printing, Go 3D offers an extensive selection of resins and accessories for purchase. Their products coupled with responsible safety practices allow capturing the benefits of resin printing while mitigating potential downsides through smart engineering controls.

Remember that safety should be the top priority when exploring new fabrication technologies like resin 3D printing. But with careful handling, the possibilities are only limited by your imagination. Print on!


1: RadTech Association Guide to Safe Handling of UV/EB Resins.

2: All3DP Article on Toxicity of Resin 3D Printing.

3: 4D Filtration Tips for SLA Printing Safety.

4: Elegoo Mars Subreddit Discussion on Safety.

5: Asian Joy YouTube Video on Resin Safety.

6: Resin Safety Tips from AsianJoy.