Laser Cutter

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=== Cleaning the lens ===
 
=== Cleaning the lens ===
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* Use acetone & q-tip [http://www.rabbitlaserusa.com/FAQ/FAQ_0/FAQ_0.html Source]
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* Use acetone & q-tip [http://www.rabbitlaserusa.com/FAQ/FAQ_0/FAQ_0.html (Source)]
 
* DO NOT apply pressure to the lens
 
* DO NOT apply pressure to the lens
  

Revision as of 21:36, 21 January 2012


Laser Cutter (Edit)
Laser cutter.jpg
Make G. Weike
Model LG900N
Date Manufactured 2011
Discipline Woodworking
Hackable No
Ownership Kwartzlab


Contents

Hardware

This be our excellent water cooled, 60W CO2 laser etching machine with 36" x 48" work area.

Software

Software that came with the machine is LaserCut 5.3 for USB. There is a hardware key that is required to operate the software.

Inkscape

Inkscape is a Free and Open Source vector graphics program. It does have the ability to save to dxf files, but in order to get a good result there are some things to be aware of:

  • There are two kinds of dxf files Inkscape can output to:
    • One is AutoCAD DFXR12 or something, and it started asking about PostScript options so I skipped it
    • The other is "Desktop Cutting Plotter (R13)". That one worked for me with default options.
  • Inkscape's dxf exporter only exports paths. In Inkscape, most things (like squares and circles and text, etc.) are not paths by default.
    • If you highlight the things you want to export and click "Path -> Object to Path" from the top menu it will convert the selected items into paths.
  • Lines in Inkscape may be given a thickness, but this will not be reflected in the output dxf.
    • The resultant document will just cut from point A to point B.
    • If you highlight a line and click "Path -> Stroke to Path" it will turn a thick line into 4 points, representing a shape that is the dimensions the line used to be
      • This should also take care of any other line attributes you used, like rounding corners or line cap styles
  • Use of Inkscape's path operations can be very helpful
    • In my example I had a black square with a series of white objects on top of it to make a shape. This made a lot of path noise in the output.
    • Instead, I highlighted everything (once I'd converted all of the objects to paths and performed "Stroke to Path" on all the lines) and used "Path -> Union"
      • This joins all of the paths that overlap into one path that traces the outline (Don't use this for inner surfaces like holes)
    • For inner surfaces, like holes, one can use "Path -> Difference" to use one path to cut a hole out of another shape.
      • This is what I eventually did with my square with shapes over it. I unioned them all together, then used that result to cut the shape out of my square, leaving me with one square with a man-shaped hole in it.
  • One last thing to remember, I don't know if this is typical or not, but while Inkscape shows you the border of your "page" surface, it doesn't output a rectangle there.
    • If you want to cut out around whatever it is you've made, you'll need to add the border directly

After figuring this stuff out, I had pretty good results moving from Inkscape into the laser cutting software.

Operating Procedure

http://www.kwartzlab.ca/wp-content/uploads/2012/01/Kwartzlab-Laser-Cutter-Procedure.doc
http://www.kwartzlab.ca/wp-content/uploads/2012/01/Kwartzlab-Laser-Cutter-Procedure.docx

1. Prepare CAD File

Prepare a file using your favorite CAD software. Export it to one of the supported file types. Transfer the file to a USB storage device.

  • DXF (AutoCAD) -- you can export from Inkscape (For best results, refer to above guidelines), Corel Draw, SolidWorks
  • AI (Adobe Illustrator) -- Save in an older pre-CS Illustrator format with no extra features for best compatibility
  • PLT- HPGL Plotter file
  • DST – Tajima
  • BMP – Windows Bitmap
  • NC – Mastercam
  • JPG File
  • JPEG File
  • GIF file

2. Remove Junk

Open the front lid on the laser cutter and clear any material from the cutting bed before turning it on. This is important because the laser head will return to the home position when powered on.

3. Turn On Laser and Fan

Turn on the laser cutter by rotating the power key to the on position and then rotating the stop button to the right.

Turn on the venting fan, which has its own separate power switch: there is a white 6 outlet power bar on the floor that you must turn on.

4. Check Laser Tube

Open the panel at the back of the unit and visually verify that the laser tube contains water. Squeeze the tube to make sure that there is water pressure. Make sure that the venting fan and water pump are running.

5. Start Software

  • Quit the LaserCut software on the laptop, if it is running.
  • Unplug the blue USB cable running from the laptop to the laser, then plug it back in.
  • Start the LaserCut software.

This procedure is recommended because the software occasionally loses communication with the laser cutter, and this is the way to restore communication.

6. Set Up Job

Import the file that you want to cut.

Set Laser Speed and Power:
You can cut or engrave different parts of your drawing using different speed and power settings. Here's how. In the upper right corner, there is a table of one or more "layers": each table entry has a colour, a mode, a speed, and a power. Initially, the entire drawing is black, and there is one layer, black. You can create additional layers by selecting subsets of your drawing, and clicking on a colour icon in the bottom row, which assigns a colour to the selection. Double click on a layer to set the laser speed and power for that layer (which controls the speed at which the laser cutter will move and the amount of power that the laser will output). You should also specify a mode (engrave or cut). The laser power setting for engraving will be much smaller than the value that would be used for cutting. The settings will also depend on the type of material that you are cutting. Be prepared to use some scrap material to run test cuts until you have the settings correct.

7. Set Up Material

Place the material that you want to cut onto the cutting bed. Use the X-, X+, Y- and Y+ buttons in the LaserCut window to position the laser over the middle of the material. Hold a button down for continuous movement.

Once the X and Y position is set, you can move the Z axis to focus the laser. If the material is hard and flat then you can use the automatic method to focus the laser. If the material is soft or thin then you must use the manual method to focus the laser or the optics could be damaged.

Automatic focus method:
With the laser positioned over the middle of the material, press the Z Datum button from the control software. The Z-axis will rise until the sensor is triggered. The sensor is the cylindrical brass finger beside the optics. Once this is done you should manually check the focus with the focusing tool (see photo below).
WARNING: Do not press the "Z Datum" button when the laser is in home position, or the laser will crash into the shelf and will need to be realigned.

Manual focus method:
Lower the Z-axis, leaving enough room to place the material underneath the laser head plus 60 mm. Slowly raise the Z-axis while using the Focus Measuring Tool to check the height of the laser head. When the Z-axis is at the right height, the laser head will line up to 55 mm. The "Tool" is a 15mm x 58mm clear acrylic rectangle with the word TOOL engraved on it, with an overhang to mark the height of 55 mm.
WARNING: Do not lower the Z axis all the way to the bottom. There is no limit switch.

8. Send Job to Laser Cutter

Click on the ‘Download’ button to send the file to the laser cutter. Note that the button is labeled ‘Download’ but it really means ‘Upload’.

Click on the ‘Del all’ button in the ‘Stand-alone file manager box’.

Click on the ‘Download Current’ button and the file will start transferring to the laser. Close the ‘Stand-alone’ file manager box when the upload is complete.

9. Verify Laser Positioning

Click on the ‘Run Box’ button while watching the cutting bed. The laser head will move in a box shape to indicate the cutting area. Verify that the material is underneath the box. If it is not, reposition the material and press the ‘Run Box’ button again. Do this until you are certain that the box is over the material.

Note that this shows you the bounding box of the last job to be downloaded to the laser cutter. If you've changed your job, make sure to download it again before using the "Run Box" command.

10. Run Job

Close the lid and press the ‘Start’ button. The laser will start cutting the material and will beep when the cutting cycle is complete.

WARNING: Do not walk away while the job is running. Monitor the job, and be prepared to hit the red button and use the fire extinguisher if it catches fire. Small flames are okay, but a general conflagration may damage the laser cutter.

11. Remove Material from Laser

Open the lid. Use the "Datum" button in LaserCut (in the X/Y axis cluster) to move to laser out of the way, back to the home position. Remove the material.

12. Turn Off Laser and Fan

Turn off laser by hitting the big red button. Turn off the fan at the power bar on the floor.

DOs & DO NOTs

A member shall not damage the laser cutter, or by inaction, allow the laser cutter to be harmed.

DO

  • DO watch the laser while it is cutting at ALL TIMES. DO NOT walk away. DO NOT go to the bathroom.
    • It takes less than a minute for a fire to start and damage the laser.
  • DO load material carefully onto cutting bed.
    • Try not to smash the honeycomb with the corner of your material.
  • DO use common sense when experimenting
    • Think ahead and be aware of any potential hazards

DO NOT

  • DO NOT bottom out the table (Z-axis).
    • There are no limit switches at the bottom and the table will become uneven, requiring realignment. If you bottom it out, do not bring it back up without verifying the table is level.
  • DO NOT press Z-datum (autofocus) while the head is in the home position.
    • The autofocus switch is not over the table in the home position. The table will crash into the head, pushing it up, and it will need to be realigned.
  • DO NOT autofocus on soft material (cardboard, cloth, soft wood).
    • The autofocus sensor will squish the material. The table will hit the head. The focus point will be incorrect.
    • Instead, use a hard piece of material (acrylic, wood) of the same thickness to autofocus; or manually set the focus point.
  • DO NOT lean on the cutting bed. The honeycomb is fragile.
  • DO NOT cut inappropriate or dangerous material.
    • You can't cut metal. (You can engrave anodized aluminum, or etch paint off of metal.)
    • DO NOT put magnesium in the cutter. It may catch fire, the fire burns hot, and cannot be extinguished by normal means.
    • DO NOT use plastics containing chlorine. They will release a gas that corrodes the laser cutter.
    • Lexan/polycarbonate cuts poorly, and the gas gums up the optics.

Maintenance

TBD

Cleaning the lens

  • Use acetone & q-tip (Source)
  • DO NOT apply pressure to the lens

TODO

  • Move laser to shop, build laser room
  • Buy or make autofocus assist plates of various thicknesses, for autofocusing soft material
    • Aluminum/plastic plates of 0.5mm, 1mm, 2mm, 4mm etc..
  • RFID Access Control

Speeds & Feeds

Raster Engrave

Material Speed Power Notes
Anodized Aluminum 250 40

Vector Engrave

Material Speed Power Notes
Anodized Aluminum 75 100
Acrylic 30 30 Not great. Some fogging (Heat damage?) of the lines and some of the tighter sections were messy. Text was readable, though.

Vector Cut

Material Speed Power Notes
Acrylic 20 100 Seemed to cut fine, was likely overkill. The edge wasn't smooth, but was more wavey than rough.

Reference

Manuals

Other

Other Hackerspace Lasers

Retrieved from "http://kwartzlab.ca/wiki/Laser_Cutter"
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