Laser Cutter Certification

…beginning of a strawman for cert doc…

This doc is obsolete.  Its contents have been incorporated into the slide deck for Intro to W88 Laser Cutter.

What you need to know to use the Workshop 88 Laser Cutter

Please don’t use the laser unless you are certified to do so!

  • What is it?
    It’s a (big frickin’) ~40 watt CO2 laser in a protective cabinet with the ability to direct the laser beam’s XY position anywhere in a 20”x12” area. The infrared laser beam can burn through appropriate materials up to about 1/4” thick, or burn the surface away, engraving detailed images. It is a 2-dimensional imaging device that cuts or engraves only things that have a flat surface. The cutting beam is invisible, so a red guide laser shows where the beam will hit.The control system for the laser is driven from Windows machines over Ethernet. On Windows machines that have the RetinaEngrave 3D software installed, it appears as a printer. Printing to the laser cutter from any Windows application generates a job for the RetinaEngrave application. RE provides a rich collection of options and adjustments to control how the engraving or cutting will occur, and allows the user to start the engraving or cutting job on the laser.
  • Laser appears as a Windows printer
    • You use the laser by “printing” your artwork from any Windows app – likely Inkscape or other vector editing tool
    • From Mac/Linux, (ToDo: not yet understood.  PDF or other files -> Windows print queue?)
  • You need to understand raster and vector images and tools
    • Sorry, but this distinction and how they behave is fundamental.
    • You’ll almost certainly need to be familiar with a vector editing tool like Inkscape.
    • You might be able to stumble into a way to cut something without understanding what you’re doing, but we don’t want you stumbling around the laser.
  • What the laser can do
    • Cut a vector path thru many materials
    • Engrave a raster image, either 1-bit or with dithering, grayscale
    • Handle up to 7 vector paths with different speed/number of passes by stroke color coding
    • Materials
      • As a certified basic user you may ONLY cut approved materials
      • Paper, cardboard
      • Acrylic, typically 3mm, max 6mm
      • NOT POLYCARBONATE!
      • NOT PVC
      • Foam (which types??)
      • Wood/plywood up to 6mm (1/4″)

 

  • How the laser can kill you and others and/or burn down the space

The laser is the most dangerous tool in the space.  Ways it can kill you or others include:  Poisoning with toxic fumes, death by fire and electrocution.  The COMPLETELY INVISIBLE beam can blind you or others and cut thru your flesh more easily than thru acrylic.  This is not an exhaustive list.

  • Safety:
    There are four safety considerations with the laser cutter –

    • Workshop88 premises: The laser cutter burns through materials, so fire safety is critical. Never leave the machine unattended, as material may catch fire while it’s being cut or engraved. Know the location of the fire extinguisher, and verify that it’s actually there. Never operate the cutter without the exhaust system running. Use the air assist when cutting materials that can flame up.
      [Add section here on what to do in case of fire in the laser.  Needs some research – I’m sure lots of people have already come up with good rules.  Turning the fan off sounds good.  Should it have an interlock thru the big red button?  Need to explain how the fan and air assist influence fire situations.]
    • Environmental safety: The cutter can vaporize noxious materials, or emit toxic fumes when inappropriate materials are cut. For example, PVC and vinyl emit chlorine gas when burned. Don’t cut any material without knowing what fumes might be emitted. See <a>link to suitable materials</a>
    • Preserving the laser cutter: The cutter is delicate compared to some of our other machines. It has exposed expensive parts: the lenses, mirrors, and laser tube are delicate and expensive. It has expensive parts that wear out: the laser tube will fail after a few hundred hours, and the power supply will need replacement someday. Never run the laser without cooling water circulating in the system. Never run without exhaust.
    • The operator’s safety: Never defeat the cover interlock that prevents the laser from operating with the cover closed. With the cover closed, the cutting beam will not leave the cabinet. The red laser guide beam is capable of injuring your retina (NB: check this) so beware of reflections. The laser tube has a 20,000 V High Voltage power supply in the cabinet which can easily kill you. Do not put your hands near the laser tube unless you know that the machine has been unplugged for at least one hour.
  • How you can damage the laser
    The cooling water pump and the exhaust fan MUST be running when the laser is cutting or engraving.  The air assist compressor MUST be running when you cut; should also be running when you engrave.  Cutting the wrong materials can produce fumes that can damage the optics.  Oh, and kill you.  When engraving, the acceleration ramp area must be clear or the gantry can crash.  If mirrors get loose and become misaligned, the beam can get loose inside the enclosure and damage anything it hits.  YOU ARE RESPONSIBLE FOR WATCHING OUT FOR THESE.
  • How to do a basic engrave and cut job on the laserCooling+Exhaust5838
    • Starting up the laser system and loading material
      • Turn it on: the laser, the exhaust fan and the water pump are all on the same switched power strip, currently on the floor on the left side of the cutter. Turn on the power on the strip. You should hear the exhaust blower start running.
      • Check for bootup: the front panel on the laser indicates when it’s successfully received an IP address. If the front panel isn’t lit up when the power strip is on, make sure that the power to the laser is on. The laser power switch is the large red button on top of the cutter. It turns on by twisting clockwise.  (Pressing it down is the emergency shutoff.)
      • Home the laser: the control panel on the front of the cutter has a row of touch screen buttons. Use the third button, which has a picture of a house above the letters AF. The description of how to use the control panel can be found in the Retina Engrave User’s Manual.
        The laser will not cut or engrave if it hasn’t been homed prior to use.
      • Open lid, check for clean work area: Before putting material in, check that there’s no leftover bits from previous users under the honeycomb. Lift up the honeycomb, then put it down and make sure it lays flat.  (Good users clean their cutoffs out before leaving.)
      • Place your material in the cutter.  You can place material wherever you like on the honeycomb material.
      • Jog to material: Using the arrow buttons on the front panel, jog the pointing laser to the starting point. The red dot should be at the upper left corner of where you want to cut or engrave.
      • FocusAdjustSet focus: The laser has a fixed focal length lens on the carriage that must be at a fixed distance from the material to make the best cuts. To adjust, loosen the thumbscrew on the front of the carriage, then raise the sliding lens carrier. Place the small aluminum cylinder (ToDo: where will this be??) on top of your material under the lens carrier. Lower the lens carrier till it touches the cylinder, then tighten the thumbscrew and remove the aluminum billet.
    • [lots to fill in here]
  • How we manage laser cut materials.  (Need the answer first!)
  • The certification test

[Pretty much include the whole test here.  We want people to know what they need to know.  Unfortunately, it’s up to us to know that so we can ask all the right questions!]

Final lab test is designing and making 2 copies of your own certification certificate – one for you and one for the wall.


How about running a class periodically?  Entrance requirement is raster/vector understanding and being able to use some vector image editing tool.  This would allow us to go thru all the dumb RE stuff once instead of individually with each person.

I (jw) think part of how we slant/color the doc should reflect that our users/readers are expected to be fairly technical.  We’re not running a laser shop for dummies .  We’re just providing an introduction for people who haven’t been exposed to this stuff yet.  This thought came up while trying to decide about including a discussion of the air assist’s fire prevention purpose while talking about fire safety and the laser.  My conclusion was yes, explain to these technical people about what air assist does.

Where to post speeds and feeds for the common approved materials?  This doc?  The main laser doc page?

While it could be argued that “safety first” should dictate how the doc starts, I chose to start with really basic, relevant stuff.  The safety stuff is there (if incomplete), and I (jw) suggest we assume people will be responsible, rather than beating them over the head with dire opening paragraphs.  Others may disagree 🙂

Someplace we need to talk about cleanup.  It’s pretty critical to take the honeycomb out and sweep up the bit you’ve cut out.  That’s not just a neatness thing – it’s so the honeycomb sits flat on the bottom.  Probably also something about managing the scrap.  One person’s cutoff is another person’s raw material.  OK – a 1/2″ square probably isn’t worth saving, but I’ve seen lots of cutoffs thrown out that should have gone in a scrap material bin for use by someone else later.