Alternate Wash Solutions for SLA Parts

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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. 

You may currently experience 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. IPA is our recommended post-processing solvent. Without it, your ability to continue printing and washing parts might be impacted. 

While IPA is our top recommendation for washing parts, we can share other recommended solvents and solutions that our customers have used successfully. We recommend Form Wash and Form Cure to automate and simplify your post-processing. Form Wash automates the print washing process for consistent, thorough, no-mess cleaning, while Form Cure 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.

 

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.

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.

Continue Reading About TPM

Other Potentially Available Solvents

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 alternative solutions 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. 

We know this is a critical time for businesses and individuals across the globe, and for many, access to 3D printing resources are vital. If you have any questions about 3D printing with limited resources, please don’t hesitate to contact our support team for help. 

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