Cleaning Resin 3D Prints: Alternative Wash Solutions for SLA Parts
Post-processing your parts is crucial to the SLA 3D printing workflow. Rinsing, washing, and curing allows you to produce highly functional, detailed parts and finish your parts effectively. For the detailed workflow, read our guide to post-processing resin 3D printed parts.
In general, IPA is our recommended post-processing solvent for cleaning resin prints. Without it, your ability to continue printing and washing parts might be impacted. However, you may have experienced the global shortage of IPA wash solvent due to COVID-19 or your facility may be unable to use IPA due to flammability concerns or local restrictions. For these cases, we can share other recommended solvents and solutions that our customers have used successfully.
We recommend Form Wash and Form Cure alongside Formlabs desktop printers, and Form Wash L and Form Cure L for large-format SLA printers to automate and simplify your post-processing. Form Wash and Form Wash L automate the print washing process for consistent, thorough, no-mess cleaning, while Form Cure and Form Cure L precisely combines heat and 405 nm light to consistently post-cure prints.
When handling wash solvents, always consult the safety data sheet (SDS) from the supplier as the primary source of information and ensure appropriate ventilation when handling.
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In this webinar, Matt Lewis and Ricky Hopper walk you through an overview of the improved SLA line, and give a hands on demo of the new products.
Washing SLA Resin 3D Printed Parts
Resin 3D printed parts must be washed to remove sticky, excess resin from the surface. Failing to properly wash parts will leave the parts sticky and unseemly, so post-processing is vital to successful 3D printing.
Washing Resin 3D Printed Parts Tips:
- Formlabs recommends washing SLA parts with isopropyl alcohol (IPA) or tripropylene glycol monomethyl ether (TPM). Most users find IPA is more effective for washing parts. Note that IPA solutions can often only be bought in large quantities, so you should be prepared to store excess IPA for future use. Check for local availability before deciding the best course of action.
- Parts should be moved around in the solvent as well as soaked for optimal cleaning.
- Parts should be washed before removing supports.
- When creating designs with narrow channels, such as microfluidics, a syringe may be necessary to clean our internal resin and stop resin from curing and blocking channels.
- Some parts may require two washes in IPA or TPM to be fully clean. Before finishing, we recommend washing in water. For each part, you should use your own judgement whether the part is fully cleaned.
Methods to Extend the Lifetime of Your IPA
If you have access to IPA, there are a few things you can do to prolong its usability. First, you’ll want to thoroughly wipe off any excess resin from the part and build platform before submerging them in IPA.
“You can soak parts printed in Standard Resins in warm, soapy water and then manually scrub the surface with a dedicated scrub brush or toothbrush,” recommends Jake Kapusta, senior services expert at Formlabs. He finds that this helps to free up some resin before you finish washing your parts with IPA.
“I’ve been more careful about saving IPA,” says Kevin Gautier, business development at Formlabs. “This includes wiping down the build platform to remove excess resin before putting the object into the wash. Another technique I found that works well is to use compressed air to blow uncured resin off the platform and back into the resin tank before washing.”
When curing the parts in the Form Cure, you can also submerge small parts in a bath of clean water, glycerin, or mineral oil inside of a glass Pyrex container. The water, glycerin, or mineral oil helps exclude oxygen from the surface of your printed part as you post cure, resulting in a tack-free well-cured surface. If your wash IPA is dirty, this step will help minimize residual resin left on the surface of your print by ensuring it is fully cured.
If you’re printing with biocompatible resins, you’ll need to closely follow wash recommendations to ensure biocompatibility of the material. For more detailed information about washing your prints, continue reading on our support site to learn more about rinsing stages, best practices for different part geometries, and more.
Tripropylene Glycol Monomethyl Ether (TPM)
Formlabs generally recommends the use of isopropyl alcohol (IPA) with a concentration of at least 90% to clean and dissolve uncured resin. In case you cannot acquire IPA, tripropylene glycol monomethyl ether (TPM) is a tested alternative for parts printed with non-biocompatible Formlabs resins.
TPM is a non-flammable, low odor solvent, making it effective for washing parts printed on Formlabs SLA printers using Form Wash, Form Wash L, or Finish Kit.
If you’re interested in acquiring TPM for your workflow, we recommend this list of approved vendors:
- J R Hess Company - TPM is available in 5 gallon pails. Please contact by calling 1-800-828-4377 ext 115.
- UNIVAR USA - TPM is available with a $500 minimum. Please contact by calling their Sales & Customer Service U.S. Toll Free number: 1-800-531-7106.
- BRENNTAG - Please contact by calling 1-610-926-6100.
- As always, feel free to contact the Formlabs sales and services team for further recommendations.
To learn more about integrating TPM into your workflow and special disposal requirements, please continue reading on our support site.
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Other Potentially Available Solvents and Resin Cleaning Solutions
Formlabs does not officially recommend any of the following, but some customers have shared with us their experience using other potentially available solvents. Customers looking for IPA alternatives for resin printing can test these at their own risk to see if they may work for their use case:
- Poly-Flush SLA 3D Printing Cleaning Solvent - Is less volatile but more expensive than IPA.
- Yellow Magic Water Based Ink Cleaner - Is less volatile than IPA and may require an ultrasonic bath to clean parts more effectively.
- MeanGreen Cleaner - May require an ultrasonic bath to clean parts more effectively.
- Propylene Carbonate - Is less volatile and requires more agitation than IPA.
- Dipropylene glycol monomethyl ether (DPM) - While this is another wash solvent used widely in industrial 3D printing, Formlabs recommends TPM as a better safer alternative.
As always, all solvents and resins should be disposed of in accordance with your local regulations and supplier’s SDS. Water and solvents contaminated with alcohol and liquid resin should never be poured down your sink drain. Continue reading our support article for more information on proper resin disposal.