80 watt laser engraver

super rough notes, don't even look at me pls

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
make sure the exhaust fan is outside, plug it in and cover up the gap in the bay door
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

regurgitate the above here

Powering up the machine

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.

Open cutting area and remove any objects from the working bed.
Plug in circulation pump to a 110v circuit. (currently does not power on with chiller),
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.
Set up ventilation fan outdoors, leave unplugged but switch unit on.
- During colder temperatures only run exhaust while cutting is taking place.
Activate power to laser cutter from switch on back of unit.
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 laptop.

Focusing the Laser

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Figure 1. laser path visualization

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.

Focal Depth:

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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.

Shutting down the machine

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

Activate E-stop to render the work-area safe.
Clean out remnants from the cutting area.
Turn off power from the key switch, this will turn off the work-light.
Deactivate/put away exhaust fan
Power down voltage converter (green switch)
Unplug circulation pump
Turn off power to back of unit

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(laser coin) to fine tune your desired results

charts of material x thickness

Acrylic
Thickness	Etch		Cut
Thickness	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

Process notes

google sketchup -> dxf via http://www.guitar-list.com/files/skp_to_dxf.rbz
take file to laser laptop
open dxf in autocad save as 2004 dxf
import in lasercut5.1
download button
download current
do setup tests for function, focus,
use test to setup test piece
verify cut/engrave speed and power settings
use test to setup work piece
cut

Laser Coin

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

Follow the start up procedure as above
Load the LaserCut5.1 project (file open) desktop\protospace random\codohundo\LaserCut2012.01
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
Set the next two layers to your chosen cut settings using the same procedure
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
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.
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
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.
Ensure the lid is closed, the exhaust fan is on, and the circulation pump is plugged in, then press start.
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.