91.548 Meeting 12: Laser Cutting

This week we are using our new Trotec laser cutter.

The basic procedure is illustrated below. We use CorelDraw to draw a vector or raster image, print it to the Trotec driver, and then use the Trotec driver to talk to the laser:

It's also possible to use the HPGL file format—which we already know—as a go-between so that you can write code that describes objects to be cut:

Your task:

Play with the laser. Make something cool.

For materials, right now we have cardboard. The foam core doesn't work too well 'cause the foam just melts.

I'll get some acrylic plastic sheeting. You can also engrave on “found objects.” Beware that PVC plastic should not be cut: it emits chloride gas, which is toxic. Cardboard is a good prototyping material anyhow.

Suggestions:

• Think of an object you want to make. Draw it in CorelDraw. Output it on the laser cutter.

• Create an object that needs to be assembled in three dimensions from a set of 2D panels.

• Play with vector modes (cutting) as well as raster modes (engraving).

• Write code to generate a family of like objects, something that would be unreasonable to draw. In order words, exploit your ability as a programmer to describe and create something that someone who lives solely in the point-n-click world could not make.

• Make big stuff! The bed of the machine is 28” by 17”—use it!

• Make small stuff, or many copies of a little thing.

Important safety notes:

• Learn how to adjust the power levels. There are two primary settings: laser power (up to 100%) and speed (from .01 [slowest] to 100 [fastest]). The highest power setting is then 100% power at 0.01 speed.

  Too high a power level will cut burn through some materials and may start a fire (see below).

• Stuff can (and does) catch fire. It's easy to get the laser power set too high, and then cardboard and wood will readily ignite.

  So don't walk away when the machine is cutting.

  IF SOMETHING DOES CATCH ON FIRE, open the lid, remove it, and stamp it out.

• NEVER CUT PVC OR OTHER CHLORINATED PLASTICS. Chlorine gas is toxic to people and will corrode the machine.

  Acrylic plastic is safe to cut.

Laser cutter links:

• MIT Media Lab Laser Cutter Tutorial. Highly recommended reading which includes safety tips.

• Trotec Laser home page. We have the “Speedy II” model with a 45W laser.