Newbie- Cutting polycarbonate

[BuckeyenNJ]

I have read as much as I can about cutting polycarbonate and it seems there are varying opinions. I need to cut .220" polycarbonate...I do not care about brown edges etc...they will be hidden. I am looking at a 100w or 150w large format Chinese laser. I know about the gases and I think I can deal with that prior to exhausting the fumes outside.

So will either of these cut polycarbonate? Secondly could the power be turned down enough to engrave .220" acrylic? Engraving is not critical but would be nice. Opinions or experience please.

[zax15uk]

If possible I would substitute polyester or Acrylic but if that isn't possible the polycarbonate could be cut with suitable exhaust precautions.

It may be necessary to cut in several passes to minimize the melting. A longer focal length lens (at least 2.5-3.0") may help also but would be the opposite for the engraving.

Zax.

[Tweakie]

With my CO2 laser, polycarbonate tends to melt better than it cuts as opposed to acrylic which cuts better than it melts. Great edge quality although some raising of the surface around the edges has to be expected with polycarbonate.

It does not take very much CO2 laser power to engrave / cut acrylic and 'depth of cut', 'power setting' and 'axis speed' are all tightly related so for engraving to a defined depth if the power setting is reduced to minimum and the engraving is still too deep then the axis speed has to be increased. If the engraving line width can be increased then defocusing the beam will also produce a slight reduction in power (but not much). Raster engraving is probably preferable to vector engraving in this instance and I think you should be able to achieve excellent results.

Tweakie.

[bpoulin]

If you are going to be doing strictly Poly, have you considered a CNC router/engraver? It can cut the outline you need, and engrave in the poly without the issues of the laser. They can also be a bit cheaper than the laser.

[BuckeyenNJ]

I will be cutting acrylic also, the laser will give an edge that I do not have to polish like a routed edge....Also I need to cut right angle corners in some notches....laser will do that better....I would love to have both machines but do not have the room at the moment. My acrylic edges will show...but the polycarbonate edges will not so I can stand some discoloration.

[bpoulin]

What will be the largest size material will you be cutting?

[BuckeyenNJ]

The final product size depends but I need to be able to cut on the laser at least 40" x 68" or so. In acrylic I have 4' x 10' stock. 51" x 100" so I need a big bed...the bed size does not add that much to the overall cost once you get into the larger format lasers.

[bpoulin]

I may have a good solution for your needs, I'll PM you a little later today.

[BuckeyenNJ]

Does anyone know how air assist would work to cut Poly? it has been recommended.

[zax15uk]

You definitely want to use air assist for poly, it will help keep the fumes off the lens and also push the molten material through the kerf. If you have Nitrogen rather than CDA it will help to reduce the dark edge too.

Zax.