Full Spectrum Laser Cutter

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Full Spectrum Hobby Series Desktop CO2 20x12 Laser

Helpful Links

Preparing a DXF to cut on the Full Spectrum Manual for the laser

Approved Materials

Material	Minimum Thickness	Maximum Thickness
Acrylic	1/16 in	1/4 in
Bamboo	1/32 in	1/4 in
Cardboard	1/32 in	1/4 in
Masking Tape	1 layer	2 layers
Paper (Printer)	1 sheet (held down)	10 sheets (held down)
Poster Board	normal	normal
Wood (General)	1/8 in	1/4 in
Wood (Ply)	1/8 in	1/8 in

Ask a manager if you would like to cut any materials not listed above.

MANAGERS: Absolutely no PVC nor Vinyl is to be used in the Laser Cutter under any circumstances whatsoever. Also we don’t allow the use of that compacted brownish material the Architecture students use under any circumstances either.

See the [[material database]] for help with settings.

Overview

We have a Full Spectrum Laser Hobby Series Desktop CO2 20x12 Laser with RetinaEngrave 3D. Here are some quick facts:

• It’s an 40W CO2 laser that uses an invisible far infrared beam for cutting.
• It does a good job cutting through things with carbon in it, e.g., paper, cardboard, bamboo, wood, and acrylic… even up to 0.25 inch bamboo and 0.5 inch acrylic. ABS is possible, but discouraged because of the terrible fumes (even worse than acrylic).
  • We have sheets of Acrylic and Bamboo on hand for sale if you need them.
• Cutting materials that contain Chlorine are NOT allowed, like PVC.
• It will not cut metals. And it won’t do much to non-anodized Aluminum or Copper.
• It can mark some metals, especially anodized Aluminum and sometimes steel.
• It theoretically has a 20 x 12 inch working capacity… but we never push it for more than about 18 x 11 inch just because it’s very hard to align the very edges of the material, and the mirror head can hit the rails if you’re a little misaligned.
• It acts like a regular Windows printer: you simply print to it from any standard Windows program that can run on PC that runs the Lasercutter.
• Popular programs to print from in the EPL: InkScape, Gerbv (for solder paste stencils), SolidWorks, Acrobat Reader (for PDFs), Word.

Theory of Operation

There are two basic modes of operation:

1. Vector – draw lines, “CNC style” set of paths at various power levels. It’s fast and clean looking.
2. Raster – draw “scan lines” which are pixels across the entire piece. Can only pulse on or off every pixel, so you essentially get dots. To get gray scale, use Halftone techniques. Slow and pixelated.

In either case, setting the power level correctly is not trivial.

See the [[material database]] for help with settings.

Power and Speed settings

There are slightly different settings depending on whether you’re using vector or raster modes:

Vector mode

• Vector Current % [0 - 100] must be set per job, where 100% is presumably 80W for our lasercutter.
• Speed [0 - 100] is the speed that the head moves along the vector path – the faster it goes, the less power it transfers to your material and thus the less effective power.
• POW [0 - 100] is the pulse width modulation of the beam, and is set per layer, where each layer is defined by color (RGB value), where there are 7 possible layers: black, red, green, blue, yellow, cyan, and magenta.

Raster mode

• Raster power [0 - 100] presumably the same as vector current, which is where 100% is presumably 80W for our lasercutter
• Raster speed [0 - 100] which is like vector speed - the faster, the less effective power.

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Lasercutting overview

Lasercutter software shows up as a color printer in Windows. You can “print” to the laser using any software that has a print button, however using something that has good control over dimensions and is vector based is recommended.

Here is how to cut something in the either of the two different modes:

Vector mode

1. Turn on the laser cutter and run RetinaEngrave3D and leave both up and running.
2. Use a vector image program, like Inkscape or a PDF viewer, and print to the lasercutter.
3. Assign the 7 colors to their layers, which you set the order of cutting as well as vector speed and POW.
4. Run your job

Raster mode

1. Turn on the laser cutter and run RetinaEngrave3D and leave both up and running.
2. Inside RetinaEngrave3D, import a bitmap from File > Open.
3. Play with the pixelization, halftoning, DPI, size, etc using RetinaEngrave3D settings.
4. Run your job.

Raster and Vector:

1. Make the Rastered part of you’re project (logos, text, etc) black and the cut lines lighter colors like yellow.
2. Print to RetinaEngrave
3. On the Raster tab set the B/W cutoff to a high enough value so only the black raster shows
4. On the vector tab set the repeat of the black layer to ‘0’ to suppress vectoring
5. Choose Raster then Vector for the mode.
6. Run your job

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Detailed Procedures

Computer prep

1. Login to the computer
2. Turn key on laser cutter to turn on laser cutter. If that doesn’t turn it on, rotate the stop button until it snaps out.
3. Wait for laser cutter to boot and get an IP address (shown on the LCD front panel).
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4. Start up RetinaEngrave3D by clicking on the desktop icon
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5. Press ‘H’ to home the laserhead. You’ll get “0 0 0” for your current position and “Connected” and “Homed” in the status bar.

Retina Engrave Toolbar:

1. Open the file you’ve designed in the design software of your choice (or just a pdf or whatever)
2. File > Print
3. Select “Full Spectrum Engineering Driver”
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   • If you have trouble printing with a message like “bounding box image invalid” try setting the paper to C size:
4. Click OK, Print and then wait.
5. Inside RetinaEngrave3D set the layer order, speed, power, repeat and vector current. See [[material database]] and/or the test pieces for setting these levels.

Using Retina Engrave

IMPORTANT READ THIS CAREFULLY

Your pattern is from (0,0) to (+i,+j) in RetinatEngrave3D. However, the laserhead parks at (0,0) and CAN’T go positive, it can only go negative. So, you need to move the laser head to the origin of your workpiece (which is the upper left corner, like in RetinaEngrave3D).

The laser cutter is at 0,0 where + is off to the right and - if off to left, but this is NOT how your pattern out is aligned: your pattern is from (0,0) off to the right.

TL;DR: YOU WILL HURT THE LASER CUTTER BY ENTERING POSITIVE ‘MOVE TO’ VALUES

Getting Ready To Cut

1. Put your material in laser cutter wherever you like.
2. Use the arrow keys on the PC’s keyboard to move the lasercutter head to the UPPER LEFT corner of where you want to cut. It’s got a red laser so you can see exactly where it’s going to start
3. Test the outline of your image to make sure it fits on your material. Hit the ‘P’ key (for Perimeter Steps) once per side and watch where the laser goes. Adjust your material or head appropriately. Make sure that the laser head is back in the upper left hand corner of your piece (on the screen, the red dot should be in the upper left at (0,0)
4. Set the focus see “Adjusting Focal Length” below
5. Turn on water pump, air pump, and ventilator are on by turning on the power strip
6. Verify that the water pump, air pump, and ventilation pump are on by feeling them
7. Hit ‘G’ for go and while it’s cutting, WATCH THE CUTTING. HIT THE STOP BUTTON IF ANYTHING GOES WRONG.
8. Move the head out of the way of your material by homing the laser head by hitting ‘H’
9. Yay! You cut a part. Rinse, lather, repeat

Adjusting Focal Length

Chuck has cut out a focal length measurement tool - the FOCUS!

1. Place the material you are cutting onto the cutting bed.
2. Jog the laser focusing assembly over your material.
3. Put the focal length measurement tool into the focusing assembly, and loosen the focusing assembly’s z-axis lock in order to move the assembly until the measurement tool is just barely contacting your material.

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Laser Settings Detail

Raster Mode

From Image

You can import a grey-scale bitmap image as your project. Be sure to set the DPI of the bitmap file in your image program to get the correct size of the final piece.

1. In Retina Engrave choose File > Open File or Project
2. Choose your image file (.bmp)
   • Example Image:
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3. If your bitmap has greyscale data it is clipped by default. The B/W Threshold slider in the control panel controls what level is the difference between black and white
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4. If you desire greyscale you have to pick a dithering scheme
   • Simple Dither makes dots further apart for lighter and closer together for darker
   • Halftone Dither Attempts to use a halftone algorithm to space the dots
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5. Set Raster Power and Raster Speed for your material
6. Follow above directions for placing and testing the perimeter and running the laser

From printer

1. In your graphics software get your job ready for printing
   • Size should be respected from your drawing tool’s geometry
2. Follow the above directions for printing a file to Retina Engrave
   • Note: make sure “Ignore Raster” is NOT checked in Import Options in the Control Panel
3. Follow the above directions setting the dither or black/white cutoff value
4. Set Raster Power and Raster Speed for your material
5. Follow above directions for placing and testing the perimeter and running the laser

Vector Mode

1. In your graphics software get your job ready for printing
2. See above directions for printing to Retina Engrave
3. Check that the file imported everything
   • It sometimes chokes on large or complicated paths. Repeat import until it works.
4. In the control panel a Vector Layer will have been created for each color it detects
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5. Set the desired settings for each layer
   • Layer: The color of line
   • Order: When the laser will cut this line. Useful for cutting inside details before cutting out an outline
   • Speed: Speed of laser head during cut
   • Power: The PWM power of the laser during cut
   • Repeat: How many times to make pass over this cut. Set 0 to ignore a color
   • Contained Objects First: If checked it will try to cut lines inside closed shapes first. Does not seem to work currently
6. See above directions for placing material and running laser
7. Run job

Raster then Vector (both in one job)

If you want to, say etch words in the top of a panel, then cut out a part and not have to run two jobs (and therefore not have to do alignment between runs) you can choose to run raster then vector in the same job.

1. In your graphics software get your job ready for printing
2. Be sure to have the part you want rastered in black and cut lines in a lighter color like yellow
3. In the raster tab set the B/W Threshold so no cut lines show in the raster view
4. Set raster power and speed
5. In the vector tab set the speed and power for your cut lines
6. Be sure to set the black layer to repeat: 0. This will ignore the black since it will be rastered
7. Follow the above directions for placing and running the laser
8. Select Raster then Vector from the laser mode drop down
9. Run job

TODO

• Write Z axis table SOP
• Things that go wrong
• Maintenance
• Ideas for improvement