80 watt laser engraver

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Gotchas

• ALWAYS DOUBLE CHECK THAT WATER PUMP IS RUNNING, it is turned on by plugging in extra cord that comes out of water cooler
• ALWAYS BE READY TO HIT THE ESTOP BUTTON (BIG RED GUY) if something is not doing what you think it should you can stop it with the small stop button but that may not react fast enough, when it doubt hit the ESTOP reset and try again.
• cutting order is often strange, don't freak out if it looks like it skipped a section, it will come back
• engraving and cutting can be put in same file, when you get them into lasercut select cuts and push them to a later layer (select line, select layer colour)
• think about cut order, if it matters push cuts to different layers, e.g. shark with eye cut out, cut out eye first then shark, otherwise shark could fall away or move before the eye has been cut
• laser does not cut at lower power levels (TBD) ~ 25 - 30%. Head moves properly but no cutting (although it still may be firing)
• after long cuts LaserCut5.1 often looses contact with the laser, file->reconnect will often restore connectivity, if not: save your project, close LaserCut5.1 unplug the usb connector to the laser, reconnect it, restart LaserCut5.1, open your saved project.
• DXFs exported directly from SketchUp via the plugin linked below tend to crash LaserCut5.1 first filter them through autocad on the laser laptop, see the sample workflow below.
• Always save your project in LaserCut5.1, you never know when it will crash and the laser is routinely emptied of all files.
• Sometimes the laser keypad will not respond to certain input (laser, test, jog) hit ESC once or twice should put it in a mode that will accept input.
• The pause button seems to work, but resuming gives odd behavior, it's probably best to stop and start again.

Required Reading

Importance of focusing/lens choice http://www.thefabricator.com/article/lasercutting/the-importance-of-focal-positions-in-laser-cutting Focus on the surface, under the surface, or on the bottom surface.

Using the machine

3 Procedures must be followed as prescribed

1. Safe Power Up Procedure to be performed whenever the machine needs to be turned on
2. Pre-Cut Check to be performed before the first cut and after any break between cuts, don't assume the machine is as you left it.
3. Safe Power Down Procedure

Safe Power Up Procedure

With very few exceptions, the same order of operations should always be maintained for safe proper operation. Failing to enable a portion of the cooling system will damage the laser.

1. Verify the cooling tank has enough water.
2. Turn on the circulation pump, sometimes it's unplugged from the black power bar, sometimes the black power bar is turned off, plug it into the black power bar ONLY, and ensure the power bar is on.
3. Power on 120-240 voltage converter (box on trolley with green light-up switch).
   • Verify that power is applied to the chiller and air pump. These are 220v appliances and need to be plugged directly into the voltage converter. The display panel on the chiller should light up, and the hanging pump should now be vibrating.
4. Activate power to laser cutter from switch on back of unit.
5. Deactivate E-stop with a twisting motion, and power on laser with key switch on front panel. The key had 3 positions, rotating clockwise the positions are off, off, on.

The laser is now active and ready to accept instructions from the computer. Warning! The laser is a stand-alone unit and can move/execute programs/fire the laser with the laptop disconnected.

Pre-Cut Check

1. Ensure the circulation pump is running
2. Ensure the air pump is running
3. Ensure the exhaust fan is on (this one will frequently be turned off between cuts so always check it)
4. Verify the work area is free of obstructions
5. With a hand over the E-Stop, run a test to see if the cut envelope will cause the head to collide with any obstructions (weights, sides) Do not allow the head to collide with ANYTHING when in doubt hit the E-STOP and reset with the workpeice re-positioned or the obstructions removed, in extreme cases you may have to modify or abandon the cut.

Shutting down the machine

Following the same steps in reverse order will help ensure the machine is left in a safe mode.

1. Activate E-stop to render the work-area safe.
2. Clean out remnants from the cutting area.
3. Turn off power from the key switch, this will turn off the work-light.
4. Turn off the power switch at the back of the laser.
5. Deactivate the exhaust fan
6. Power down voltage converter (green switch)
7. Unplug circulation pump

Focusing the Laser

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Figure 1. laser path visualization

Use the Z+ and Z- buttons to raise and lower the table. There are a few considerations when selecting a focal depth:
Warning! The Z+ and Z- keys work independently of any software control. It is possible to change the z height to values that would crash the the workpiece into laser head, particularly while the laser is operational. Be very cognizant of where everything is while you are moving the table!

Depending on the thickness of the material and whether you are cutting or engraving you will need to set an appropriate focal distance. The beam does not come out of the lens parallel, but in fact is conically shaped. See: Figure 1.

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Figure 2. Focal Depth: Bottom shows resultant cut shape.

For engraving, you want the focal point right on the surface for the fastest/most efficient results.

For cutting, you want the focal point to be near the midpoint of the thickness of the material so that it makes the straightest edges on the cuts. See Figure 2.

Load the program!

The LaserCut5.1 software is a bit tricky. See: Sample Workflow (below)

Cut the loaded program!

Once a cut program has been loaded to the laser from the LaserCut5.1 software, the laser head should be aligned with the workpiece.

1. Select the project loaded to the laser on the LCD menu, It is the text on the top right of the main menu.
   • Multiple files can be loaded on the machine.
   • The file should be 'selected' (highlighted black box over the name). If not, press the ESC key to reload the main menu and the file will be selected.
   • Pressing the left/right key should cycle through the loaded files.
2. Jog the laser head to the intended origin with the arrow keys
   • In order for the jog keys to work, nothing can be selected on the menu, hit ESC so that no text is highlighted on the screen. When done, to return to a working mode ESC must be pressed again to select the file.
   • This is the same origin as set in the loaded file; it can be anywhere on the table. Common selections are 'top left' of the piece or 'centre' of the workpiece.
3. Ensure the workpiece is aligned by using the 'Test' function.
   • The machine is unaware of the head's location, and will happily destroy itself if bad instructions are given.
   • Be ready to shut down the machine if the head appears to be going out of bounds.
   • Press the 'Test' key to have the laser head draw a bounding box around the outer limits of your project.
4. Once everything is aligned, press the 'Start/Pause' key to start the cut.
   • To pause the cut, press 'Start/Pause' again. One more press will resume where the program left off.
   • To abort the current program (something is horribly wrong), press the stop key. This will abort the program and it will have to be restarted from the start. The head should home back to the origin from before the program was started.

Cut Guidelines

These charts are intended to give you a starting range, from which you must dial in with testing, use scrap that is the same material and thickness as your intended work piece and use a small test pattern( e.g Laser Coin) to fine tune your desired results

WARNING! Above all other warnings, never, ever, EVER cut or engrave anything with the word vinyl, pvc, polyvinyl chloride, etc in it's name. It will release forms of chlorine gas (incredibly toxic and caustic) which will quickly degrade the components in the machine. Even with the exhaust running, the 'smoke' from cutting pvc can permanently damage the machine and your face. DON'T DO IT!

charts of material x thickness

Acrylic
Thickness	Etch		Cut
	Speed	Power	Speed	Power
2mm	?	?	?	?
6mm	?	?	?	?

?
Thickness	Etch		Cut
	Speed	Power	Speed	Power
2mm	?	?	?	?
6mm	?	?	?	?

?
Thickness	Etch		Cut
	Speed	Power	Speed	Power
2mm	?	?	?	?
6mm	?	?	?	?

Sample Workflow

This is *a* workflow that has been working consistently, there are other tools and processes that will work but to get started

First, ensure SketchUp is installed and working correctly. Then install the export to DXF plugin (http://www.guitar-list.com/files/skp_to_dxf.rbz)

Starting from scratch:

1. Start a new SketchUp project and select a metric mm template
2. Draw your model as 2d line work on the XY plane, Tip: use the overhead camera view.
3. Select the part of your model to be exported to DXF (can select all)
4. Use the plugin to create the DXF file, select mm as the export unit and export as lines
5. Transfer file to laser workstation
6. Open dxf in autocad save as 2004 dxf
7. Follow the startup procedures as above
8. Follow the pre-cut procedures as above
9. Test cut/engrave settings on a sample of the target work material (e.g. do Laser Coin Test)
10. Import in lasercut5.1
11. Divide the project into appropriate layers, first layer should be engraving, second layer should be for internal cuts and a final layer for the outer cut
12. Set engrave/cut settings for each layer
13. Set laser origin (Laser -> set origin, top left)
14. Hit the download button at the bottom of the panel on the right
15. Hit delete all
16. Hit download current, this can take some time if the project is complex, if it takes too long you may want to break the cut up into smaller chunks.
17. Follow the pre-cut procedures as above
18. Hit start
19. Follow the safe shutdown procedures as above

Laser Coin

To test etch and cut speed and power settings as well as the focus:

1. Follow the start up procedure as above
2. Load the LaserCut5.1 project (file open) desktop\protospace random\codohundo\LaserCut2012.01
3. Using the above charts as guidelines (also refer to the sample cuts kept by the laser), set the first layer to your chosen etching settings by double clicking the first layer and filling in the selected properties
4. Set the next two layers to your chosen cut settings using the same procedure
5. Download the coin project to the laser by clicking on the download button, this will bring up a dialog that shows all files currently on the laser, select delete all (I hope people remembered to save their projects), then download current, this shouldn't take very long
6. Ensure the work area is clear of all obstructions and the laser head is starting safely away from the edges and has enough room to travel, use the arrow keys to jog the head over to a safe starting location if necessary, this project is small so starting in the middle is safe.
7. Select a scrap of the same material and thickness at least 3cm x 3cm and place it under the cutting head with the head starting at the upper left hand corner of the test piece
8. Hover one hand over the ESTOP button (BIG RED GUY) and be ready to hit it if the head is going to crash into the side, please do not allow it to do this, if in doubt please e-stop it and start over. On the laser control panel hit test and watch the path of the laser, it should stay within the confines of the test piece, if not adjust and retest or select a larger scrap.
9. Ensure the lid is closed, the exhaust fan is on, and the circulation pump is plugged in, then press start.
10. If the results are satisfactory you can now start setting up your project following the same basic procedure, otherwise adjust the settings and test again.

Note if the etch isn't smooth but otherwise looks good, try bumping down the speed of the etch layer and bumping down the power, keeping in mind that power settings below %30 are unreliable.