Cutting ABS

projectinspo

#1

I really want to experiment with cutting ABS plastic. I realize that ABS plastic is a challenging medium to work with, due to the low melting point, and tendency to distort when heated. Will the Glowforge expose a lot of fine control over the laser cutter to allow me to experiment with differing cutting techniques? (Movement speed, laser power, cut duration, etc)

I realize that you are still probably don’t know the exact specs of the model of laser that will be included in the product, but in general, do you know what kind of temperatures the cutter will operate at?

This would be good info to have, as a material with a flash point lower than that temperature will be on the ‘OMGOMGFYRE!!!111’ list.


Few material questions
Inventables two color ABS plastic
#2

Temperature is a somewhat complicated subject - see this post:

To answer your first question, if you choose to do ‘custom’ cutting settings, you will have control over beam power (256 different levels 0…255), focus (which is software controlled!), and speed. You can then save those settings and use them again later.


#3

Lasers don’t have temperatures(they are just photons, no mass so therefore just energy), the longer the laser is on a material and depending the material it is on the hotter it will be. Same goes for if it is black, white very conductive or absorbs CO2 wavelengths well

ABS can be done, your best chance is googling it, there are great sites that show excatly how materials react under different settings(not a 1:1 answer for GF but gives you a good idea). You can work with ABS but it’s dependant on how good of finish you want, acrylic will do a better job 99% of the time and there are other good materials.


#4

Good info, thanks all. I look forward to experimenting and melting some plastic.


#5

I’ve done ABS quite a bit on an Epilog; I’m looking forward to doing it on my GF when it ships…

The general “secret” to doing ABS comes down to three things: speed, power, and cooling. ABS melts at relatively low temperatures, which is why we all love to use it in our 3D filament printers. If you blast through it like you do acrylic or Delrin, what happens is it either burns or it fuses back together and melts into a blob.

I’ve found lots of success with high speed, low energy level passes repeatedly over an area, and running an air assist nozzle on the laser head to cool the material rapidly. In doing so, I used to cut a lot of panels of moderate (8x12 inch) size and also a lot of dashboard inserts (custom “car computers” back in the 2002-2004 era…)

It will work and look decent, but it looks nowhere as good as cutting acrylic or Delrin, or other plastics better suited for this work. You can also do Lexan, but it has the same issues and seems even more prone to flare ups.


#6

I read a scary thing about cutting ABS on a few sites.

ABS Emits cyanide gas and tends to melt ABS does not cut well in a laser cutter. It tends to melt rather than vaporize, and has a higher chance of catching on fire and leaving behind melted gooey deposits on the vector cutting grid. It also does not engrave well (again, tends to melt).

The first bit that puts me off


#7

That’s the reason you should seriously consider using the vent option vs. filter. Most melting/burning plastics offgas nasty stuff and while HEPA/Charcoal is great for smoke and particulate matter, gas goes right through. If you are interested, there is good scientific survey-of-the-literature type paper available at: http://fire.nist.gov/bfrlpubs/fire86/PDF/f86017.pdf

To your other point - yeah, I never had success in getting good engraving on ABS. I tried everything, but the melty nature of makes it unsuitable. It’s hard enough for me on the milling machine to get decent cuts because it heats up rapidly and balls up. I found the best thing was to carve out a section and embed an insert with the engraving I wanted… usually I just used some scrap acrylic, engraved and paint-filled to level it, in an inset…kind of like a guitar fretboard would have inserts. It looked nice enough.

Fire is always a concern… I found a good air assist and keeping an eye on things were always the path to success… with a good compressor running all the time, the cooling was enough, and I was scrupulous about keeping the honeycomb cutting bed clean of debris.


#8

I was going to try to work like you suggested, low power & fast movement. Since GF is pretty high precision, I think that making repeated passes would not be an issue.

I was also thinking of putting the ABS in the freezer prior to cutting might give you a little more of a delta in temperature before you hit the melting point, although this might just cause thermal expansion fractures.

Also, when cutting something like ABS that might get messy if cut improperly, I was thinking of putting a unglazed ceramic plate or dish under it to simplify clean-up. This idea set off any red-flags for anyone?