Smoothing 3d prints with acetone

[theycallmevirgo]

I'm in the process of 3d printing some injection molds, and I was looking at some tutorials for surface smoothing with evaporated acetone. My concern is that some of my models have concave features that the acetone will not reach. Is there a dilution that will still be effective? Alternately, what if I cycle pure acetone in and out with the injection system?

Many thanks in advance

Joe

 

[berkeman]

I'm in the process of 3d printing some injection molds

What material are you printing with? Injection molding involves pretty high pressures, so thin-walled plastic would not typically be used.

 

[theycallmevirgo]

Currently PLA, but of course later I would like to run ABS and nylon. Of course I do pretty thick walls for injection molding

 

[Tom.G]

I was looking at some tutorials for surface smoothing with evaporated acetone.

Acetone is very flammable, and Acetone vapor is explosive. I suggest using a safer solvent.
Try this search:https://www.google.com/search?&q=solvent+for+pla

 

[theycallmevirgo]

I mean, I don't disagree, and I will definitely follow your suggestion, but there are so many tutorials with acetone all over the place. Surely someone would have said something by now?

 

[Tom.G]

Surely someone would have said something by now?

Apparently they didn't, so I figured I had better say something.
(we don't like loosing members)

Cheers,
Tom

 

[dlgoff]

(we don't like loosing members)

And/or member parts.

 

[TeethWhitener]

Acetone is less flammable than gasoline (edit: but more flammable than pure ethanol). Do with that info what you will.

 

[minerva]

You said you're using PLA, so acetone won't do anything as it doesn't dissolve PLA.

This technique is commonly used with acetone on ABS, not on PLA.

Having concave surfaces or cavities won't matter.

The object is not immersed into liquid solvent, it's immersed into the saturated vapor phase above the surface of a heated liquid solvent in a container.

Just because lots of people do it, it doesn't mean it's risk free - heating up a volatile, flammable solvent outside of a fume hood *is* a fire/explosion risk.

For this to work on PLA, a different solvent that dissolves PLA is needed, like THF or dichloromethane.