RePPA: A Game Changer for Resin 3D Printer Post-Processing and IPA Recycling

A company has launched an accessory to post process resin 3D prints and recycle the solvent!

Fabbaloo readers may recall a story we published last summer, where we reported on rumors of an “all in one” resin 3D printer post processing device were circulating. Now it appears that has come true.

Why an all-in-one device? I think any resin 3D printer operator would agree that the current state of print post processing is a mess. Literally a mess: multiple devices and equipment are required, and sloppy toxic items must be handled safely in-between them.

Consider the typical workflow for a desktop resin 3D printer:

• Print completes
• Print plate is removed (toxic drips everywhere)
• Print is pried off the plate (more drips)
• Washer is opened up
• Print is placed in washer (more drips)
• Washer runs through its cycle
• Print is removed from washer (more drips, but IPA)
• Print is dried with air, towel or blower (more drips)
• Curing device opened up
• Print is placed in curing station
• Curing station performs its cycle
• Job complete
• You notice your IPA is now polluted with resin

You may have noticed there are several opportunities for toxic drips in the above sequence. That’s what the RePPA device is attempting to solve.

It contains what you might expect: a wash station and a curing station, but provides significant automation in the process. Here’s their version of the typical resin workflow:

With RePPA, the workflow is apparently reduced to this:

• Placing the print plate inside RePPA
• Switching it on

They say:

“No need for special protection gear, as you will have no direct contact with the chemicals during postprocessing.”

This obviously saves some manual effort, but also and more importantly creates another level of safety for toxic resin handling. That’s a good thing.

There’s another very key feature of the RePPA: resin recycling.

Every resin 3D printer operator has a tank of polluted IPA (or other solvent). This solvent will contain all the wet resin that’s been washed off a series of prints, and often it’s so dirty you cannot see through it.

It is possible to manually recycle this toxic fluid, and I’ve done it. You simply pour the toxic mess into a clear container (ideally a flat tub with clear lid), and place it outside in the sun for a few days.

After a while the resin suspended in the IPA will polymerize and sink to the bottom. You’ll get a kind of sludge, but the IPA above is clear. You then pour it off and let the sun finish off the sludge. The final solid remnants can be safely tossed.

While that process indeed works, it’s a huge pain to execute. Here the RePPA does all that automatically.

After the wash completes, the IPA is pumped out of the wash chamber. The chamber is then filled with water to wash off the remaining resin. Then, while still submerged in water, a powerful UV light cures the print — underwater. Apparently this speeds the curing process because the water carries the UV light in a better way. I’m not sure how that works, but that’s what they say.

The dirty IPA is passed to another chamber, where it is purified. They don’t explain, but I suspect they’re using a UV light to do so. Regardless, the result is perfectly clear IPA, ready for the next print job. They say the cleaning process takes only 30 minutes to handle 4L of IPA, which is quite impressive.

[UPDATE] I received further information from the project team to explain how the IPA is recycled. It sounds like they are using an “ultra strong” 14w UV light to cure the dissolved resin. They say that if the conditions are correct (meaning temperature), then a sludge quickly forms and falls to the bottom, leaving clean IPA at the top. If the conditions are not right, then “you may have to wait a couple of hours for it to settle”.

Even better, they say this means the IPA can last up to 30X longer than when using standard post processing steps with IPA. That’s a significant cost saver. For example, if a liter of IPA cost US$5, then that’s equivalent to buying 150L of IPA. For busy 3D printer operators, this could be a notable saving.

The RePPA is offered through Kickstarter, and the usual caveats should be considered before purchasing.

The RePPA is offered in two forms: basic and “Pro”. The Pro version is the same as the basic, but provides ultrasonic cleaning, metal build, faster pumps and a bit bigger volume for larger print plates.

The early bird price for the basic unit is a surprisingly low €209 (US$223), while the Pro is set at €949 (US$1012).

If you’re looking for a better solution to resin 3D print post processing, this is a product to consider.

Via Kickstarter