Why It's Important

Post-processing lets you take full advantage of your SLA printer and resin. Following the correct process will maximize the quality and mechanical performance of your prints. Stumbling blind, however, can make it difficult or even disastrous.

Here, we’ll walk you through the necessary steps and the various methods for approaching each.

Safety Precautions

Before we get started, make sure that you understand the safety precautions involved with handling SLA resins. These resins are toxic if they aren’t handled properly, and direct contact with the skin should be avoided. Spills can also get messy, so make sure that you have a clear work area.

What You’ll Need

· Nitrile gloves

· Safety glasses

· A clear workspace

If resin accidentally comes in contact with bare skin, wash immediately with soap and water. Avoid leaving resin trails on items you touch. If a spill occurs, clean it right away before the resin hardens.

With that out of the way, let’s get started with post-processing!

Step 1: Rinse Off the Part

When your part comes out of the printer, it’s covered with uncured resin. You’ll have to rinse it off before going further with post-processing.

Method 1: Ultrasonic Bath

An ultrasonic bath, like one for cleaning jewelry, is a professional (and somewhat expensive) way of cleaning SLA prints. Fill the bath with cleaner fluid to cover your print and let it sit for a couple of minutes. This will take off the fine layer of uncured resin stuck to your model, leaving behind a smooth, clean finish.

In most cases, the fluid of choice will be isopropyl alcohol (IPA) in relatively high concentration, but other options exist, as well. For example, if IPA availability is limited, or if you’re looking for something non-flammable, tripropylene glycol monomethyl ether (TPM) and dipropylene glycol monomethyl ether (DPM) can be used (the latter especially in industrial applications). Formlabs recommends TPM over DPM for the average consumer.

Method 2: Dunk and Rinse

If you don’t have an ultrasonic bath, simply dunking your part into a tub of IPA works as well. Move your part around and rinse it well to get the resin off. This method is simple and quick, but will not achieve as thorough a clean as the ultrasonic bath. Two rinses or more may be necessary to strip off the resin clinging to the surface.

Step 2: Remove Supports

Next, remove the tree-like support structures attached to your model. This can be done before or after curing, but doing it before will be easier. Always watch out for stray bits of plastic that go flying.

Method 1: Break Them off by Hand

If you’re not worried about small details, breaking the supports off by hand is the quickest way to go. If your model has fine features, however, it’s best to use more caution.

Method 2: Use Flush Cutters

For more intricate parts, use flush cutters to carefully snip off the supports. Get as close to the model as possible without marring the surface.

With both methods, small nubs will be left on your print. This is inevitable but easily remedied with a little sandpaper and some patience.

Step 3: Cure the Print

The last step in post-processing is to UV-cure your print. This is necessary for many functional prints because it finalizes the material properties of the model.

Method 1: Curing Station

Many SLA printer manufacturers also sell curing stations. These are specifically optimized for their resins, allowing for finely tuned curing times. This is especially useful for larger prints and professional environments. For more information, you can check out our resin washing and curing station buyer’s guide.

Method 2: Nail Polish Curing Lamp

This is an inexpensive and accessible method of quickly curing your model. Simply place it under a nail polish lamp and let it sit overnight. Adding a turntable can help get a more even exposure.

Method 3: DIY Curing Chamber

Many hobbyists will build their own, inexpensive curing chambers, makeshift versions of commercial curing stations. This is easily done by placing a UV light in a box lined with aluminum foil. Place the model on a solar or battery-powered turntable to get an even exposure.

Method 4: Solar Power

To go fully green, use good-old solar power. Place your part outside on a sunny day, and you’ll have a nice, even, UV light. The main drawback of this approach is the extra patience required. You’ll have to sit back and let the sun do the work.

You're Golden!

With these three easy steps, your SLA print is post-processed and ready to go!

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Created by: Hironori Kondo

How to Clean Resin 3D Prints – 3 Easy Steps