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
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
put exhaust fan 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.

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

charts of

material x thickness

acrylic

2mm speed 5-10 power 100

6mm speed ? power ?

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