By the end of this lesson, you should be able to:

General Instruction for Laser Machining

1. Secure the stock. A typical example is clear, cast acrylic, 0.227" thick, coated with paper on both faces from the factory.

2. Determine the optimal power and speed settings if you have not already done so. For a description on how to do this, please see http://jcflowers1.iweb.bsu.edu/rlo/laserexp.htm .

3. Cut the stock to size, if necessary. The maximum sheet size is 24" x 12" on this laser cutter.

4. Turn on the computer.

5. Open the CorelDraw program. (The recommended software is CorelDraw, however, it is possible to use other software.)

6. Use CorelDraw to create the geometry, or import a graphic from another program. For now, please use black for cutting and yellow for engraving. Save your drawing in the appropriate directory (e.g., D:\classes\299xsp2007\).

7. Turn on the laser cutter, and wait 30 seconds for it to initialize.

8. (Sometimes, you remove a plastic protective covering from your stock and make sure the surface is appropriate for laser machining. Other times, you may coat the surface with transfer tape to minimize the effect on uncut surfaces. Also, sometimes a little water may be sprayed on one or both faces.)

9. Open the top of the laser cutter. Gently place your stock against the guide rulers at the top and the far left edge. Make sure the honeycomb support table, itself, is indexed against the guide on the left and against the back of the cutter, away from you.

10. To manually focus the laser on the top of the stock, use the focusing tool and move the table up or down. (For cutting most materials, you might find it best to move the table up half the thickness of the stock.) Press the Z button. If you need to move the table up or down, you can press the triangle up or triangle down keys - note that the Select button allows you to select tenths or hundredths of an inch increments. When you are done, press the z button to finalize your settings.

(Note, when the autofocus feature is enabled and functional you can focus the laser on the top of the stock by pressing the Z button on the laser control panel. The laser head will automatically focus by moving the table up and down. The laser is typically fitted with a 2" focal distance lens, which has a focal range of + .1". To finalize the focus, press the Z button again to return to the "Ready" display.)

11. Close the top door of the laser cutter.

12. When you are ready to cut, choose PRINT from CorelDraw. However, when the print window opens, do not select print. (Make sure the M35 is selected as the printer.)

13. Select PROPERTIES.

14. For each color of your drawing, make sure the settings are correct. You should test out possible settings on a similar piece of scrap until the you find the optimal setting. Record your results on the Laser Machining Run data sheet. Sometimes, it is best just to use a series of 8 lines, or 8 text blocks, each with a different color and different settings for power and speed. After you determine the optimum settings on the test piece, use those same settings to produce your product. Here is an example where you wish to cut through 0.227" clear extruded acrylic along all black lines, and you wish to lightly engrave with yellow areas:

Make sure the pen mode for black is VECT or RAST/VECT, because black lines are vector graphics. Click the box to change it if necessary. Click the word "black", and then change the %Power and %Speed as needed. Suggested values are 100% power and 1.2% speed when the laser cartridge is fully charged, but 100% power and 6% speed when  the laser cartridge is in need of re-charging. Click SET to accept these new values. (You had found these values by actually testing a new drawing with eight short lines, each a different color and a different setting.) Set yellow to RAST or RAST/VECT, with 100% power and 20% speed, for engraving. Make sure that 500 PPI or pulses per inch is set. Press SET.

15. Click OK to return to the print command window.

16. Click APPLY to apply the changed values to your work.

17. Press PRINT.

18. Check to see that your file has been received on the laser cutter's screen.

19. Turn on the left exhaust system. Check the exhaust.

20. Call over the lab supervisor for a final check if this is your first use of the laser.

21. Press the green start button on the laser cutter. If you need to abort the run, you can open the top cover of the laser cutter. This will immediately turn off laser power, although the motion system may continue for a while.  Don't stare at the light produced during cutting/engraving.

22. When the job is done, the laser will beep. Allow the exhaust to clear away emissions for the next few minutes, but you may open the top and remove your work and turn off the exhaust.

23. If no one else is about to use the laser, turn off the laser. The computer is typically left on until the end of the day.