Laser Cutter
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I started this for my own purposes, after fighting with the laser cutter and associated software. There are a lot of nuances.
Equipment and Capabilities
The Pratt Machine Shop has a Universal Laser Systems VersaLaser. Ours is a 45 Watt unit with an 18" x 32" work area. We have the purple case.
The laser cutter can cut many plastics, paper, cardboard, and wood, among other things. It can NOT cut polycarbonate plastic, polyvinyl chloride plastic, or metal, to name a few things.
It can easily cut acrylic (e.g. Lucite or Plexiglas) up to 0.250" thick. Most of our projects in the BME design labs use 0.125" thick acrylic. (The laser can cut thicker acrylic, but it takes multiple passes and doesn't really do a good job.)
The laser cutter is attached to a computer that has Corel Draw, AutoCAD, and Adobe Reader installed.
Generating Artwork
The preferred method of generating artwork is with Corel Draw. If you can't use that, you can probably still get by with other software. I have used the DWGeditor in SolidWorks. I have also used Inkscape, which is a GNU-licensed vector drawing package. Others have used AutoCAD.
Where you want cuts, you must have vector graphics, and where you want to etch the surface, you want raster graphics. On our system the default color for vector cuts is red, and the defaults for raster etch areas are blue and black. If you don't use the right color, you might end up trying to raster your cut, which doesn't work well, takes a long time, and wears out the mechanical parts.
The vector cuts must have zero line width in your artwork. The rastered etch should have a nonzero width. (I found that 1mm width made for nicely readable text. That depends on the overall size of your text, of course.)
You can take your artwork up to the cutter as a file on a USB Flash drive. The file should either be something that Corel Draw can open, or a PDF. I found that the laser cutter computer's installation of AutoCAD is really slow, so opening a DXF is painful.
I was cutting a large piece, and discovered that the artwork sort off "fell off" the work surface if I wasn't careful. Even though the .PDF I created showed the artwork on the paper, it still didn't fit on the cutter's work surface. This was because I was using one of the engineering sized papers, which was larger than the 18" x 32" bed. I ended up defining a new paper size of 18x32 in Windows to correct this.
Inkscape
When you draw a shape in Inkscape, it's automatically filled. That might lead to undesired behavior in the cutter. So, for example, if I wanted to cut a square in acrylic, I'd draw a square in Inkscape with a red outline (remember that red is the usual color for vector cuts) and no fill. Set the outline color (the "stroke") and the fill after you've drawn the object by right clicking on the object and selecting Fill and Stroke. Under the Fill tab, select the 'x' for no fill. Under the Stroke Paint tab, select R:255 G:0 B:0 A:255. Under the Stroke Style tab, select some really fine width, like 0.1 mm.
The line width, remember needs to be (nearly) zero or the laser cutter will raster the cut instead of vectoring it. It turns out that a truly zero width is impossible in Inkscape, but really, really thin is a close enough approximation to zero.
If (heh: WHEN) you make your lines so thin that you can't see them any more, you can go to View -> Display Mode -> Outline to show all lines, at least on the screen.
I cribbed most of the above Inkscape hints from Ponoko.
After getting your artwork just the way you want it, probably the best way to get it up to the printer is to print the artwork to PDF. I use CutePDF Writer, which seems to work well. Remember to use your custom paper size or your artwork might get cropped in the cutter.
DWGeditor
Those familiar with with AutoCAD will be at home in DWGeditor, as the latter is pretty much a clone of the former. Those of you unfamiliar with either, don't worry. It's not hard. Google "DWG Editor tutorial" and you'll come up with all the knowledge you need.
When using the DWGeditor, remember to properly set line parameters. For cuts, lines should be red, "continuous" and 0 mm wide. For text, which you probably want to etch, you should use blue or black, and set the linewidth to something that scales with the overall size of text. For most of the text I place, 1mm linewidth works.
Making the Cut
The laser cutter is attached to a computer via USB, and to the computer the cutter just looks like a printer. You print your artwork to the VLS6.60 printer, then fire up the printer interface software from the tool tray in the bottom, right corner of the screen: click the red square with the diamond in it.
If you're using acrylic sheet, remember to remove the paper backing from both sides before placing the sheet in the cutter.
Click the settings button, then set the material thickness. Click OK. Then click settings again, and go to the Manual Control tab. Tweak the power, speed, and PPI (Pulses Per Inch) settings to your desired settings. I found the following settings to work:
| Material | cut/etch | Power, % | Speed, % | PPI |
| 0.125 Acrylic | deep etch | 75 | 100 | 1000 |
| 0.125 Acrylic | cut | 100 | 2 | 1000 |
