Proper Handling of UV Curable 3D Printing Resins
The Photopolymer Additive Manufacturing Alliance (PAMA), a collaboration between the National Institutes of Standards and Technology (NIST), and RadTech, have revised their “PROPER HANDLING OF UV CURABLE 3D PRINTING RESINS,” guidance, and included a new section on frequently asked questions. In addition to the new FAQ, revised sections include: Good Housekeeping procedures, Clean up, Disposal and Storage.
With the continuing mission to advance the development of common industry terminology, practices, protocols, and standards, PAMA is producing a new workshop, with the objective of “Building a Unified Vision from Research to Regulations.” This is a follow-up to the very successful NIST/RadTech event in 2019, bringing together suppliers, users, academia and government. The PAMA Workshop for photopolymer additive manufacturing is September 18th-19th, 2023, in Boulder, Colorado. The event will enable candid, pre-competitive conversation regarding the state of the field of photopolymer additive manufacturing through a series of panel discussions and develop updated, comprehensive roadmaps for current and future directions.
CONSULT MANUFACTURER DOCUMENTATION
- Consult Safety Data Sheets (SDSs) provided by suppliers of UV curable resins as the primary safety and handling documents.
- 3D printers have built-in safety features that are designed to prevent operator exposure to uncured photopolymers and UV wavelengths – do not try to change or disable these features.
USE PERSONAL PROTECTIVE EQUIPMENT [PPE]
- Wear appropriate chemical-resistant gloves (nitrile or neoprene) – DO NOT use latex gloves. Gloves should have extended cuffs if available.
- Use safety glasses/goggles.
- Wear a labcoat or suitable covering over personal clothes.
FOLLOW GOOD HOUSKEEPING PROCEDURES
DURING SET UP
- Avoid placing a 3D printer over carpeted areas or use a barrier to avoid the possibility of carpet damage.
- Do not locate dedicated work/personal spaces in close proximity to the printers if odors are a concern.
- Do not expose UV curable resin to heat (at or above 110°C/ 230°F), flames, sparks or any source of ignition.
- 3D Printers and uncured, open resin vats should be stored and operated in a well ventilated area or with local exhaust.
- If UV curable resin comes in a sealed cartridge:
- Inspect the cartridge before loading it into the printer
- Do not use a cartridge that is leaking or damaged. Dispose of it according to local regulations and contact the supplier.
- If the UV curable resin is in a pourable bottle, carefully pour the liquid from the storage bottle into the printer tray, avoiding spills and drips.
- Tools that may be contaminated with the material should be cleaned prior to reuse with plenty of ethanol or isopropyl alcohol, or as indicated by the resin SDS, followed by a thorough washing with soap and water.
- Keep work area clean.
- Wear gloves when handling parts directly from the printer.
- Wash the parts before post-cure using a manufacturer’s recommended solvent, such as isopropyl or rubbing alcohol.
- Ensure that all 3D printed objects are fully post-cured by exposure to a UV light source after forming, in accordance with the printer or resin manufacturer’s recommendations. This should be done before the printed object is handled without gloves.
PRACTICE PERSONAL HYGIENE
- Do not eat, drink or smoke in work area. Remove jewelry (rings, watches, bracelets) prior to handling uncured UV curable materials.
- Avoid direct contact with any UV curable resins or contaminated surfaces, including any parts of the body or clothing. Do not touch the resin without wearing protective gloves and do not get it on your skin.
- Wash hands, face or any body parts that may contact UV curable resin with mild skin cleanser and soaps after handling – do not use solvents.
- Remove and wash contaminated clothing or jewelry; do not reuse any contaminated personal items until properly cleaned with detergent.
CLEAN UP WORK AREA
- Clean any contacted or exposed surfaces to prevent contamination.
- Clean with ethanol or isopropyl alcohol or as indicated by the resin SDS, followed by a thorough washing with soap and water.
- Use absorbent rags to clean spills immediately.
KNOW FIRST AID PROCEDURES
- Flush contaminated eyes or skin thoroughly with plenty of water for 15 minutes. Wash skin with soap and plenty of water or waterless cleaner if needed.
- If skin irritation or rash occurs, seek qualified medical attention.
- If ingested, do not induce vomiting. Seek medical attention immediately.
PREPARE FOR DISPOSAL
- Fully cured resin can be disposed of with household items.
- Cure unreacted UV curable resins by leaving them in sunlight for a few hours or expose them to a UV light.
- Partially cured or uncured resin waste may be classified as hazardous waste. This includes clean-up materials containing UV curable resins. Please check your state’s website for disposal of chemical waste or your local professional waste haulers. Do not pour into the sink or dispose into the water system.
- Keep UV curable resins sealed tightly in their containers, out of direct sunlight and within the temperature range suggested by the manufacturer.
- A small headspace of air is needed to keep the resin from gelling.
- Do not fill resin containers to the top of the opening.
- Do not pour used, uncured resin back into new resin bottles.
- Do not store uncured resin in refrigerators used for food and beverage storage.
RADFAQ UV 3D/ADDITIVE MANUFACTURING SAFETY
Which is the best safety mask to wear when working with UV 3D/additive manufacturing printing resins?
The best safety mask to wear would be whatever is specified in the Safety Data Sheet (SDS) that should be included with your resin. Unfortunately, many resin suppliers do not include a proper SDS with their containers of printing resins. The best mask would be one that is specified for the most volatile or irritating component of the resin. The challenge is that most manufacturers do not identify what component that is, specifically. However, the good news is that the vast majority of UV curable 3D printing resins are not very volatile and would not require a mask when using the printer in a well ventilated area. It would be most practical to use a mask that is rated for organic vapors such as the kind painters might use (not a simple dust type face mask).
What gases come off a UV curable resin?
There are very few gases that come off the resin. What operators smell is a minute level of the most volatile components in the starting material used to formulate the resin. These components will likely be those with the lowest molecular weight. The nose is a very sensitive odor instrument, so it does not take much for us to smell trace amounts if the resin has been formulated correctly and with the end user in mind. It is important to understand that what can be smelled is FAR below what is recognized as a “permissible exposure limit” (PEL) for chemicals of this type. This is why natural gas companies add trace levels of a sulfur compound (rotten egg smell) to natural gas, as a person will smell the sulfur and know immediately if natural gas is leaking. Careful handling of the resins you use and adherence to safety recommendations will ensure a safe experience.
Are UV 3D Printing resins toxic?
It is important to recognize that some of the components in a 3D resin blend could pose some moderate human health or environmental effects, if not handled properly. It is imperative to review the SDS that accompanies any resin blend and to follow the recommended personal protective equipment (PPE) and disposal requirements listed on the SDS. As with any chemical product, all manufacturer instructions should be followed to ensure proper use and handling. Once a 3D figure is properly printed, cured and rinsed, the resin should essentially be non-toxic.
The information provided in Safe Handling of UV Curable 3D Printing Resins is believed to be current at the date of publication. The guidelines found in this Guide may not cover all applicable legal requirements. RadTech is not responsible for the conditions of use of particular 3D printing systems. It is the user’s responsibility to determine the safe conditions of use of a particular 3D printing system. The guide is offered in good faith and is believed to be reliable; however it provided neither warranties not representations for any of the products it mentions. RadTech disclaims any and all liability for the damages incurred directly or indirectly through the use of this document. Nothing contained herein should be considered a recommendation to use any particular company’s product. Contact your checmical and equipment supplies for additional information. © 2023