Wiki
Although you’re welcome to read through this material in advance of a laser authorization class, reading this article does not authorize you to use the lasers at denhac. This document is mostly for trainers to make sure they don’t miss anything important while training.
To be authorized to use the laser cutters at denhac, a member must demonstrate to a trainer that they have the skills and knowledge listed in the following categories. If there is not a laser training posted for the lasers on our events page then feel free to request one in #help-laser-pew-pew on slack. Even if you’ve used CNC lasers extensively, we still need to see you demonstrate your competency for insurance purposes.
Introduction
How do the lasers work?
The lasers are a CNC machine, meaning we use computers to specifically control the movement of the gantry. There is a CO2 laser tube in the back of the machine that, when energized, creates the laser that we’re using to ablate the material. The laser is bounced around a few mirrors so that it ends up in the nozzle where the lens is at. Underneath the lens in the nozzle where a high pressure stream of air is injected that encapsulates the now focused laser beam and keeps smoke away from the lens. Once the laser hits your material it will light it on fire, and the high pressure stream of air (what we call the air-assist) ensures that the smoke from your stock material doesn’t get deposited on the lens. Take a look at the diagram of the laser focus (should be hanging on the material tests board)
– Navigate to the Allowed Laser Cutter Materials wiki page (or look at the lasered wooden list near the lasers) (don’t laser things that burst into flames or release toxic gas)
– Navigate to the #help-laser-pew-pew Slack channel
– Close the laser cutter lid gently
– Press and reset the Emergency Stop button
– Point to the standard fire extinguisher (fires outside the laser, just stomp on the fire if you feel safe doing so)
– Point to the halon fire extinguisher (fires inside the laser)
– Point to the laser safety goggles
– Point to the air assist pump, the fume extractor fans, and the chillers (Max 24*C). (ALL OF THESE THINGS MUST BE RUNNING WHEN OPERATING THE LASER)
– Say “In an emergency, dial 9-1-1”
– Point to the laser maintenance cabinet
– Clean the laser head mirror (Students shouldn’t have to worry about this but demonstrate how to stab and twist to lift debris from the lens/mirrors. DO NOT WIPE the q-tip across the surface)
– Say “Don’t Walk Away from a Running Job” (These machines are literally burning stuff, don’t make that stuff the space. We want everyone to be present for their laser fires)
Basic Use
– Turn the machine on
– Place material in the print area and adjust focus height
– Use the arrow buttons on the laser to orient the nozzle somewhere convenient
– Set the origin (not terrible useful if you use the [start from -> current position] option in the laser control section of lightburn
– Press the Pause/Unpause button on the machine
– Talk about the use of laser weights and how bowed material can change your focal height if you do your cuts before your etching and engraving
– Explain the differences with the white laser (No adjustable honeycomb, manual focal height adjustment)
– Talk about the different material tests and how to read them
– If you encounter an error on the laser, press the ESC button to clear it and try again
– The white laser currently has an issue with the lid, just push on the right side of it near the e-stop in order to close it all the way and press the switch underneath
Lightburn & Computer stuff
– Login to a laser workstation
– Open or save files on the NAS (Network Attached Storage / Z Drive) (Easiest way to get a file to the laser computers)
– Lightburn isn’t much of a design program, Adobe Illustrator/Inkscape/Fusion/etc are better for design. Lightburn is just for telling the laser which settings to use for each part of your design
– Create shapes
– Create text
– Adjust object sizes
– Configure a line
– Configure a fill
– Center and alignment tools, scaling, location settings (all in the top ribbon of lightburn)
– Set a path’s layer, speed, power, and passes (the little tags at each workstation tell you the laser’s max speeds and stuff) (max speed only applies to x-axis motion aka engraving, max speed in y direction is ~70mm/s) (do your cuts last or you might throw off your z height/focus setting)
– Pick an origin setting
– Preview the job
– Frame the job
– Start the job
– Pause the job in LightBurn
– Unpause the job in LightBurn
– Talk about how moving the material after cutting will lose the origin of the design. Pressing the User Origin button before moving can be helpful to store that location
– Design a simple nameplate and run the job
– Be nice to our scrap, check out the scrap wiki page!
– Do not move your stock after cutting until you’re sure that the
– Create a material test (Laser Tools menu -> Material Test)
– Alignment with the gantry, not the honeycomb (it’s just floating around in there)
– This is where the magic happens, learn to use lightburn through youtube and stuff to improve even more.
Cleanup
– Turn the machine off
– Return tools to their homes
– Remove materials from the bed
– Clean the laser head mirror
– Clean the honeycomb (use the shop vac if necessary)
– Put useless scrap in the trash. Also, be nice to the scrap, keep larger continuous pieces in the pile. Break off any useless bits and only store the usable parts. See this article on laser scrap for examples.