OmtechLaser

You see before you an OmTech Polar 350, a 50W CO2 laser for engraving and cutting various materials.

Photo of Omtech laser cutter at the space

In the desk drawer below the laser, you find a rotary attachment for engraving round objects.

Currently, Thomas (TEM01* on discord) has taken responsibility for this machine. If you have questions, contact him or someone else certified to use the laser.

Laser Documentation, Use, and Rules

This document is not considered a replacement for an in-person training on the laser. In person training is required before use.

What Can I Cut or Engrave on the Laser

The laser is pretty good at cutting and engraving many materials made of hydrocarbons, and a few that aren't. When choosing materials for the laser cutter, materials that cut well without burning or melting are desired. Many hard plastics work well. Materials that are thicker than ¼ will not cut on the laser, the focal length of the lens we use is too short. There are a few materials that are not safe to cut, and are banned. This is typically for one of 3 reasons:

• They release too much sticky smoke, which builds up in the enclosure/ductwork and is a fire hazard.
• They release poisonous gas, for example, cyanide. Avoid plastics with a carbon-nitrogen bond. Research new plastics and get in touch with someone before use.
• They release corrosive gas (which is also poisonous). Do not cut PVC (vinyl) based materials, or any other materials with chlorine or fluorine atoms.

Category	Material	Engrave	Cut	Comments
Wood-Based	Plywood	✔	✔
	Wood	✔	✔
	Balsa	✔	✔
	Cardboard	✔	✔
	Paper	✔	✔
	Cork	✔	✔	Burns Easily
	Hardboard/MDF	✔	✖	Releases large amounts of sticky smoke when cutting
Cloth	Cotton	✔	✔
	Natural Leather	✔	✔	Look up the tanning method to ensure it's not toxic
	Artificial Leather	✖	✖	It's basically vinyl
	Polyester	✔	✔	Melts Easily
Plastics	Acrylic	✔	✔
	ABS	✖	✖	Releases cyanide gas
	Plexiglass/Polycarbonate	✔	✖	Not recommended, as it tends to be smoky and not cut well.
	Rubber	✔	✔	Be CAREFUL. Look up the rubber and dont generate too much smoke.
	PETG	✔	✔	Clear PETG can be somewhat transparent to the CO2 laser.
	Vinyl	✖	✖	Releases chlorine gas
	PVC/PVA	✖	✖	Releases chlorine gas
	Polypropelene	✖	✖
	Polystyrene	✖	✖
	Delrin	✔	✔	Matte only
Other	Fiberglass	✖	✖
	Glass	✔	✖
	Ceramic	✔	✖
	Rock	✔	✖	Some rocks etch better than others
	Coated Metal	✔	✖	Can etch painted surfaces, or anodizing. NOT GALVANIZED
	Mirrored Surfaces	✖	✖	Reflects laser, evaluate for 10um performance before etching.

Additionally, avoid avoid overly reflective materials, or things that take a lot of energy to melt, such as metals. Remember, the laser has to either burn away the material or vaporize it, so in materials that will not burn or sublimate, there will be a liquid layer that then vaporizes. This causes interesting effects when engraving materials such as stones; sometimes leaving a layer of rock that was temporarily molten. Materials that do not burn or sublimate should not be cut on our lasers. Laser cutters used for cutting metals are upwards of 500W for a reason. When in doubt about a material, ask someone! There may be a solution to finish your project with a material that wouldn't normally be recommended if we think outside the box.

Orientation and Safety

To use the laser, first turn on the ventilation system. Currently, this is two separate fans, the large one inside the electrical closet, and the smaller fan above the laser. Plug in the fan inside the closer, then turn on the small fan by pressing "FAST" on it's controller.

The laser is controlled by the computer above it, and turned on using the key switch on the front left. When the laser is turned on, the large illuminated pushbutton can start a cutting job, so do not press it until you are ready.

Make sure to only cut approved materials on the laser, this will mitigate fire hazards and noxious fumes. The laser MUST be supervised continuously during operation. If the material being cut catches fire, or too much smoke is being generated, turn off the laser with the keyswitch. If the material being cut continues to burn, take the fireblanket out of the pouch on the wall, open the laser, and smother the fire.

Operation

The laser is controlled using the lightburn software on the computer. This takes in SVG files, or can be used to draw a design from scratch. Primary colors are used to control the different power levels for cutting and engraving.

Lightburn Overview

In this image, there are 3 rectangles to be cut. Their color defines the power and speed settings that will be used. Additionally, the color controls the order in which the cuts/engravings will be made. Generally, it is best practice to engrave any images first (black grayscale), then cut out any interior holes (blue in this case), then use the final setting to cut the work out of the larger piece of material. This reduces the chance of the material shifting and throwing things out of alignment.

On the right there is another tab labeled move. This lets you manually move the laser head over your material to make sure it is in the right area, and also autofocus to the material.

Material Settings

To help with dialing in new materials, Lightburn has a Material Test Generator utility found under tools. If you haven't used this before, ask for assistance.

Material Test Generator

This lets you make test coupons for new materials, that you can leave in the space for others to reference in the future.

Using these test coupons, you can choose the right speed and power settings for your project.

Maintenance

This laser cutter is still pretty new to EMS, so the frequency and exact maintenance steps required for this laser are still being determined. For the time being (1-2-26) here are the things TEM01* has run into in previous workplaces. These instructions have not been updated to be applicable to the OmTech Laser, and should be updated when the maintenance occurs.

Before Every Cut	Check focus lens
Weekly	Check z calibration and travel
	Check air assist
	Clean honeycomb if needed
	Check focus lens mirror
Bi-Monthly	Clean beam optics
	Check beam x-y calibration
	Clean Laser cooling fan filters

Clean focus lens:

Remove assembly

Clean front (faces down when in laser) of focus lens by dripping small amount of lens solution on the lens and gently wiping with clean q-tip or lens paper.

Honeycomb (Cutting table):

If there is a large buildup of small pieces of material in the honeycomb, take it out and empty it. When replacing, be sure to properly align, by pushing it against the guides in the top left corner.

Focus lens mirror:

Take out the lens assembly and clean the mirror as if you were cleaning the lens, but wipe along the length of the mirror instead of in circles.

Clean beam optics:

The mirror is cleaned with horizontal strokes, and the beam window with circular ones. These should only be cleaned gently bi-monthly unless visible build-up of soot has occurred.

Beam x-y calibration:

The x-y beam path does not go out of calibration often, and is very robust, but can occasionally cause problems that are very difficult to troubleshoot. The x-y mirror is adjusted to ensure that the beam is parallel to the x-axis armature.