Laser Cutter Authorization Training

Overview

Completion of the Laser Cutter Authorization Training (Laser Cutting 101: Authorization to Run) is required before a denhac member is permitted to use the laser cutters. This training covers the fundamentals of safe usage of the laser cutters, but ultimately it is up to each laser cutter user to take responsibility for using the laser cutters in a safe and responsible way.

Members can search for upcoming laser cutter authorization trainings and sign-up for them via the denhac Events page.

Prerequisites

Prior to attending an authorization training, members are expected to:

• Read through to the end of this wiki page
• Read through the Allowed Laser Cutter Materials wiki page
• Join the #help-laser-pew-pew Slack channel
• Watch the LightBurn tutorial to become familiar with LightBurn basics

Laser Cutting 101: Authorization to Run

Training Objectives

• Student will craft a small name placard for themselves using LightBurn and the laser cutters.
• Student will not maim or injure themselves (or others) in the process.
• Student will not burn down the building in the process.
• Student will avoid setting fire to the trainer, please.
• Student will learn laser safety fundamentals and denhac’s requirements for using the laser cutters.

Laser Cutter Safety

Laser cutters use a concentrated beam of high power laser radiation to vaporize away material to cut and etch. The beam is capable of catching materials on fire very quickly. The laser cutters at denhac use Class 4 lasers, which means they are capable of causing serious burns, severe eye damage, and blindness.

• Never operate the laser cutters with the lid open! Safety lockout switches always prevent this in theory. Think of the lid as a giant pair of safety glasses (since that’s basically what it is).
• Don’t put anything in the laser cutter that you don’t intend on cutting! (Recording your laser cutting by putting your phone in the machine will end in tears. It’s happened before.)
• Do not leave the laser cutter running unattended! The lasers can ignite materials quickly. DO NOT walk away from a running job! All laser cutting and engraving must be constantly supervised.
• Make sure you understand what materials are safe to cut! Review the Allowed Laser Cutter Materials wiki page. Some materials burn out-of-control. Some materials release toxic gases. Don’t burn those.
• Make sure you know where the fire extinguishers are! There is a special halon fire extinguisher that is safe to use inside the laser cutters. Other fire extinguishers may cause damage to the internals of the laser cutters and should be used primarily for fires burning outside the machine.

If an emergency situation does occur, dial 911! If a fire starts, there are two types of fire extinguishers available in the Laser Cutting Area. A standard fire extinguisher is mounted against the wall and small halon fire extinguishers sit next to each laser cutter. Once it is safe to do so, notify the Laser Cutting SIG via the #sig-laser-cutting Slack channel.

Both laser cutters have big, red, Emergency Stop buttons to immediately deactivate the laser. If you are concerned about your materials catching fire or creating a hazard, press the Emergency Stop button. The Emergency Stop buttons can be reset by twisting them clockwise.

The laser cutters are in the same space as other woodworking and metalworking tools, and those tools can be loud. Feel free to grab some ear protection available in the woodworking area.

If you have any questions about laser cutter safety, or if the laser cutters are doing something you’re uncertain about, post a question in the #help-laser-pew-pew Slack channel.

To Review:

• Lasers are dangerous!
• Burning things is dangerous!
• Join the #help-laser-pew-pew Slack channel.
• Review the Allowed Laser Cutter Materials wiki page.
• Practice pressing and resetting the Emergency Stop buttons.
• Know where to find the fire extinguishers.
• Wear ear protection if the shop area is loud.
• DO NOT walk away from a running job!
• In an emergency, dial 911.

Basic Machine Use

Power On

The Blue Laser has an on switch and The White Laser has on and off buttons. These will turn on the laser cutter as well as the air vent and water chiller attached to each. The Blue Laser also has a keyed switch to activate the laser tube. (The laser tube on The White Laser is always active if the laser cutter is powered on.) If the machine isn’t turning on, check if the Emergency Stop button was pressed and twist it clockwise to reset it if needed.

Before running any jobs, make sure the air vent and water chiller are running and make sure the water level in the chiller is good. Otherwise, the laser tube could overheat and break. The laser cutter maintenance cabinet has jugs of distilled water to fill the chillers if one is running low on water. The max operating temperature for the tubes is 24 C (75 F). If the water chiller is showing a temperature of 24 or higher, pause your job and wait for the laser cutter to cool down before resuming your cut.

Wait for the laser cutter to finish its startup sequence and moving parts come to a stop. Once the laser cutter finishes its startup sequence, check if the laser mirrors are clean or if they need to be cleaned by gently rolling a q-tip coated in IPA across the mirror. Q-Tips and IPA are located in the Laser Maintenance Cabinet.

Place Materials

The White Laser can fit materials up to 27.5″ x 39.5″ x 0.45″ (700 mm x 1000 mm x 12 mm) on its honeycomb bed. The Blue Laser has a honeycomb bed with adjustable Z-height so it can fit materials up to 29.5″ x 40.5″ x 6″ (750 mm x 1030 mm x 150 mm). The maximum cut area of both lasers is 23″ x 35″ (600 mm x 900 mm). Maximum cut depth is ~1/4″, limited by the optics of the laser.

Use the arrow keys on the laser cutting machines to move the laser head to where you want it to be for your cut job, then press the Origin button to set that location as your intended job reference point.

Adjust the Focus Distance

Using a focusing tool, measure and adjust the distance between the laser nozzle head and the surface of the material. Our lasers’ focus beam widths are the smallest and strongest at 3.7mm from the nozzle tip.

On the Blue Laser, there are Up and Down buttons which adjust the Z-height of the material and thus the focus distance. On the White Laser, the laser head itself has adjustment screws and manually moving the laser head is how the focus distance is set.

For marking/etching raster images with the highest quality set the bed height 3.7mm away from the surface of your material for the highest level of detail. The Blur heights on the tool can be useful for getting large darkened markings in areas that don’t require precision.

For cutting, it’s ideal to have the strongest part of the beam be in the center of the material. The focus tool has presets for the center of 1/8″ and 1/4″ material. The optimum focus distance may vary for different materials, so you may need to experiment and find what works best for you. Using the optimal focal distance for your material width also reduces kerf. Due to our lens focal distance you should not cut any materials thicker than 1/4″.

For engraving slightly into the surface you can play around with using different focal distances. The 3.7mm focal distance has such a small beam width which results in many ridges despite cranking up the interval/DIP. It may look better to use 6.8mm which will result in a smoother looking fill (at least on wood).

Prepare a LightBurn Job

LightBurn is installed on both laser computers. Each computer connects exclusively to its respective laser cutter (Blue Computer to Blue Laser; White Computer to White Laser).

For tutorials on the use of LightBurn, visit LightBurn’s documentation pages and YouTube channel. The device settings and machine settings are pre-configured for the specifics of our lasers; do not make changes to these settings.

When creating a project in LightBurn, do not set speeds or power levels that exceed the limits of our lasers:
Blue Laser Limits: Max Power: 80%, Min Power: 9%, Max Speed: 400 mm/s
White Laser Limits: Max Power: 50%, Min Power: 13%, Max Speed 400 mm/s

Exceeding these soft limits overvolt the tubes and burn out the gasses inside which greatly reduces the tubes’ lifespan. There’s no hardware limit preventing it, but this is the equivalent or redlining your car. Our software automatically throttles down to this number but it’s best practice to only type in values less than or equal to the max.

Before starting a cut job from LightBurn, first use the Preview function to confirm that your cuts look like you are expecting and that the layers will be cut in the order you expect. Make any needed adjustments or fixes now. Next, use the Frame function to have the laser head move along a bounding box above your material so you can confirm that the job you are preparing will fit within the area of the material you have placed in the laser cutter.

Once you have designed, previewed, and framed you job, you are ready to start cutting.

Run the Job

Before starting a job, always make sure that the laser cutter lid is closed and that all panels and access doors are closed! Then press the Start button in LightBurn.

As the laser is cutting your job, pay attention to the chiller temperature. If the chiller alarm sounds or the temperature indicated rises above 24 C, pause your job for a few minutes to let the laser and chiller cool down.

DO NOT walk away from a running job. If you need to, pause your job before you walk away from the laser cutter.

As the laser is cutting your job, watch your material for sparks, flames, and other signs that the material is going to ignite. If the material does ignite, press the Emergency Stop button. If the flame is small, lift the laser cutter lid and blow out the flame. If the flame has grown beyond small, grab the halon fire extinguisher can, lift the laser cutter lid, and use the halon fire extinguisher. If the fire has spread to outside of the laser cutter machine, use the standard fire extinguisher. If the fire is unmanageable, dial 911. Once the situation is safe, notify the Laser Cutting SIG of the situation via Slack.

If the laser cutter is not cutting as well as you would expect, or something seems amiss or broken: do not attempt to make any modifications or repairs yourself! Stop using the laser cutter and post to the #help-laser-pew-pew Slack channel with details about the problems you are experiencing.. If cuts are requiring high power and/or multiple passes something is wrong with the device or your material/settings. If you have questions, are uncertain about anything, or may have accidentally bumped something out of alignment please post in the #help-laser-pew-pew Slack channel. We want to know about and proactively fix and prevent potential problems.

Once your cut finishes, wait for a few additional seconds before opening the lid of the laser cutter. This lets the air vents clear out the smoke and smell.

Clean Up

When you are finished using the laser cutters, turn the laser cutters off (and turn the Blue Laser’s launch key to off). Return any work-holds or other tools you used back to their homes. Remove all of your materials from the laser cutter and if you have large scrap off-cuts, you can put those in the laser scrap bin. Smaller off-cuts go in the trash. Remove any debris from the honeycomb bed.

If the materials you cut were particularly smokey or fumey, clean the mirror above the laser head with the q-tips and IPA found in the laser maintenance cabinet.

Clean up the area around the computer.

To Review:

• After powering on a laser cutter:
  • Confirm that the air vent is running
  • Confirm that the chiller is running and has enough water
  • For Blue Laser, enable the laser tube with the keyed switch
• Clean laser mirrors, if needed
• Place your (allowed) material in the bed
• Move the laser head and set the origin
• Adjust the focus height of the laser head
  • Nozzle tip 3.7 mm above the material surface
• Setup your job in LightBurn
  • Blue Laser Limits:
    • Max Power: 80%
    • Min Power: 9%
    • Max Speed: 400 mm/s
    • Max Cut Depth: 1/4″ (6 mm)
  • White Laser Limits:
    • Max Power: 50%
    • Min Power: 13%
    • Max Speed 400 mm/s
    • Max Cut Depth: 1/8″ (3 mm)
• Preview and frame your job via LightBurn
• Close the lid and begin your job
• Monitor chiller temps and pause your job if needed
• DO NOT walk away from a running job!
• Pause your job if you need to walk away from the laser cutter
• When finished laser cutting:
  • Power-off the machine
  • Remove your materials from the machine and clear debris
  • Clean the laser head mirror, if needed
  • Return tools to their homes
  • Usable off-cuts can go in the laser scrap bins
    • Trash off-cuts go in the trash. Please!
  • Clean the area around the computer

Laser Cutter Maintenance

tldr: Don’t try to do anything you have not been specifically trained for. Instead, post on #help-laser-pew-pew if anything seems amiss.

Eventually, these machines will break in some form or fashion. Most likely, it’ll be the laser tube expiring, but we might also damage the mirrors and they need to be cleaned or replaced. Unless you have been explicitly authorized to do maintenance on the machine by someone who is themselves authorized to do maintenance, DO NOT open any of the side panels, mess with any of the settings on the machine, or try to fix whatever problem you’re seeing. Please just let us know about it. If you’re a member of the space and are interested in being authorized to repair the machine, we can discuss that.

If you are unauthorized, any attempt to repair the machine when broken, whether successful or not, will be treated negatively. Please just don’t do it.

Knowledge Check: Make a Name for Yourself

• Design a simple, 3″ to 5″ nameplate in LightBurn
  • Create a cut for the border
  • Create a cut for the nail hanger
  • Create an outline for your name
  • Create a fill for the date
• Preview the job
• Resolve order-of-operations issues
• Frame the job
• Start the job
• DO NOT walk away from a running job!
• Clean-up after yourself