Liquid Nitrogen, for build platform raft release


#1

Hey folks. I just received my printer, and completed my first print. Yay!

Then I discovered how challenging it can be to remove the support base from the build platform. …Good heavens, that’s really difficult!

Here’s the short: Liquid nitrogen works really well for reducing solid resin adhesion to the build platform.

I hope this tip is helpful for folks.

<tl;dr;>

I was really having a hard time getting the raft to come off of the build platform. I’d seen a number of posts about various mechanical means for removing the material, many suggesting that “it really is that difficult”. I got to looking around the garage for ideas, when my eyes came to gaze upon the LN2 dewar…

A simple experiment demonstrated that immersing the build platform in a shallow puddle of liquid nitrogen (in a small styrofoam cooler) for 10 seconds was the magic! The plastic remaining on the build platform became extremely brittle, and likely had a significantly different thermal expansion coefficient, and popped-off easily with a few taps from the scraper. I wouldn’t recommend necessarily immersing the whole build in LN2, as that might damage your part. This would only be for stubborn support base material, so you only need a few cm of LN2 in your cooler.

If you don’t have any liquid nitrogen around, it’s not as difficult to come by as you might think, if you’ve never tried. You only need an appropriate container (a dewar) to transport it in. I have one of these. I get it filled at a local welding supply shop. It costs about $50 for 10L, and will last in the tank for the better part of a couple months without usage.

Of course, you should use appropriate precautions when dealing with LN2. That being said, so long as you’re using it carefully in a well ventilated space, making certain not to spill it on yourself, others, and having an exit plan if you do spill it (like, you’re going to give it several feet of space while it boils off. There’s no cleaning this up), you’re going to be fine.

I originally picked up the dewar so I could make LN2 ice cream for my son’s kindergarten class. And have since kept it handy for all manner of experiments.

<\tl;dr;>


#2

Placing the building board with the printed parts in a freezer has the same effect.