Is anyone available to teach the Laser 101 course this afternoon (08/27/2018) or tomorrow (08/28/2018) at any time? Or is anyone with the required training willing to run the laser cutter with/for me any one of these days?
Also, I would like to verify something. The wiki page on laser cutter material says we are not able to cut polycarbonate material with a thickness > 1mm. If my part is 0.78 mm thick, is this eligible for use with the laser cutter?
So from the materials page next to polycarbonate it says: Polycarbonate is often found as flat, sheet material. The window of the laser cutter is made of Polycarbonate because polycarbonate strongly absorbs infrared radiation! This is the frequency of light the laser cutter uses to cut materials, so it is very ineffective at cutting polycarbonate. Polycarbonate is a poor choice for laser cutting in general, and the edges also turn black.
Laser will not cut it efficiently and there is risk of fire. That being said, I will be up there around 6:30-7 and willing to run machine for you but make no promises of success. This may be a very costly experiment. If you want to proceed, do you have your vector cut file already?
Thank you for the responses. I will try to find another option for cutting polycarbonate for the time being since it is short notice. If you all know of any alternatives, that would be extremely helpful!
“Thick ( >1mm ) Polycarbonate/Lexan” is on the prohibited materials list. It seems to imply that thinner material might be acceptable. The terms “Thick ( >1mm )” should be removed to make it clear that any thickness is prohibited.
JJ is right to point out that this could be very costly to experiment. If you have time, I’d strongly suggest that you get a piece of comparable, non-optically-special polycarbonate on which to experiment. It could save you $300.
I definitely agree it could be costly. There are cuts that need to be 1mm apart so it might be too risky to experiment with. Testing with cheaper but comparable material is a great idea.
@apparently_weird Thank you for offering to help this afternoon. After the input I will take more time to think about this before following through using an expensive material and attend training during the offered times.
Sounds good. I’ll still be there this evening if you want to talk. Cheaper material would be good to check your cuts with, but your material is designed to diffuse. I’m not a laser expert, but my sense is that it will enter the polycarbonate and ricchochet like a .22 bullet in a concrete bunker. This may end up being something akin to a jewelry saw by hand.
Remember to plan for kerf width if you need precise sizing and dimensions.
You will need to experiment to determine the exact kerf width because it depends on the material, the cut settings and also how the specific laser is performing on that particular day. I can’t guess what polycarbonate will do, but for other materials 0.006" kerf would be a good starting point.
EDIT: If your resulting parts will be small, you also need to devise a method to catch them after they are cut … I believe that @Nick recommended a silicon sheet, for instance.
If cutting small pieces, a silicone mat can do wonders to help you keep your pieces from falling through the grating. Also, slightly turning down the air assist may be required as well, because it can blow the small pieces away. WARNING: if you turn down the Air Assist, it is your responsibility to turn it back up. Not doing so can lead to possible damage to the machine, from someone else having a fire in the machine, due to low air assist pressure.
As for cutting polycarbonate, I’ve always remembered it as not being allowed. That said, most items on the not allowed list are there because in combustion they either release Chlorine Gas or some other toxic gas. That said, I went and looked up the MSDS for Polycarbonate and it seems that the product of it burning is CO2, CO, and a few hydrocarbons. But, nothing all that uncommon or overly scary. It also has standard fire fighting instructions. Here is a source for this, www.ampolymer.com/SDS/PolycarbonateSDS.html
So why might polycarbonate be banned from laser cutting? I can tell you one thing, it cuts lousy on a CO2 laser. Cut edges often bubble up and raise on both sides of the cut and the cut tends to stay a bit molten and can close up and stick together, giving a poor product.
So how do I cut polycarbonate at DMS? I would suggest using a router. There are great end mills for cutting plastic cleanly and leaving a really nice edge. If you need the aid of a CNC machine in your project, you can take the advanced CNC Router class to be allowed to machine plastics on the CNC Router. This would be my suggested method for your project.
The reason we do not like polycarbonate being cut on the laser is
it can generate a lot of smoke. Smoke bad for the laser optics. This is most likely the reason for the restriction on thickness of the poly. IF you do use it, please stop if smoke is being generated and not cleared by the exhuast.
It cuts poorly. smoky edges, the poly doesn’t look good after.
That said, it is on the allowed list by Thunder Laser.