Old Laser Cutter

Full Spectrum Laser Cutter

Laser Cutter Class syllabus and guide

How to use

!!Before using the laser cutter, you must first get training through an intro class or get signed off on it by the manager!!

The following is a handy reference for the steps to go from a design to the GCode that will run on the laser cutter.

Making a GCode file

On the computer for the laser cutter, there is a version of VCarve Pro that is set up to work well. Please avoid changing anything if not necessary. Since this is the same program used for the CNC routers, please do not use the program on this one for the CNC Routers as they have different settings like clearance height, feedrate, etc etc.

1. Open VCarve Pro on the Laser Cutter Computer
2. Draw/Load your design into the program
3. !!Go to "Edit", "Job Size and Position", and make sure the "XY Datum" is set to the bottom left corner!!
4. Open the Toolpaths tab on the right side of the screen. Hit the pin icon in the top right corner.
5. Select one or more of your drawing objects, then click on the "Profile" toolpath button
6. Under the "Tool" section, click the "Select" button, and find one of the tools named "LASER". There are multiple, each set up with a different power % for convenience.
   1. If you need a specific power %, please create a new tool or modify one that has "TEMP" in the name.
   2. Enter in your desired power % in the "Spindle Speed" textbox.
   3. Enter in the speed in the "Feedrate" textbox.
7. Ensure that it is only going to do 1 pass. If it is not, you can click the "Edit Passes" button and make it one pass.
8. In the "Machine Vectors" section, select "On" so that the laser will follow right on the line of your drawing.
9. Scroll to the bottom in the Toolpaths tab and hit "Calculate"
10. If the preview looks good, hit "Close" on the bottom right and click on the "Save Toolpath" button (which looks like a floppy disk)
11. Save the toolpath using the Post Processor named "J TECH GRBL (MM) (*.gcode)"

After that, you will want to copy the file over to a flash drive or put it on a local server so you can reach it from the laser cutter computer.

Running the Laser Cutter

1. Turn on the power strip with all the components for the laser cutter and computer
2. Ensure all external components are on: Fume Hood, Air Compressor, Water Pump
   1. You may need to turn on the fume hood manually
3. Open the Pronterface program
4. Click Connect (usually connected to COM4)
5. Click Load File, and find your file.
6. Look at the preview and verify that is the correct file
7. Place your material in the bed of the laser cutter, making sure it is well-aligned and parallel to the sides of the machine
8. Insert key and turn on the main power for the laser cutter
9. Use the interface in Pronterface to move the laser cutter to the bottom left corner of your material. You can use the "Test Fire" button to burn a dot to see where the laser is over your material.
10. Click the "Set Origin" button at the bottom of the screen in Pronterface
11. Click "Print" and watch it go. Keep an eye on it in case anything goes wrong. If there is a problem, hit the big red emergency stop button on the top of the laser cutter. After you do this, you have to click the "Laser Off" button in pronterface, and close pronterface. Only after that can you twist and release the emergency stop button.

Cleaning the laser

Vacuum the inside

The bed of the machine should be vacuum out regularly after cutting to clean up any small pieces that fall into the honeycomb.

Cleaning the lens and mirrors

Ask someone to show you how to clean these before attempting yourself! A dirty lens can cause burnt gunk to build up and potentially crack the lens. Here is a video from the ATX Hackerspace on cleaning their lens - How to Clean Laser Optics

Laser Cutter Materials (from ATX Hackerspace)

Original page There are a wide range of materials that our Laser Cutter can cut, etch or mark - but some simply don't work (eg metals) and some are extremely hazardous to either humans or the machine itself (eg PVC and Vinyl). It is therefore imperative that you check these lists before attempting to cut materials that you have not worked with before.

It is not always obvious which materials will work - for example: Polycarbonate/Lexan produces flames and lethal chlorine gas which will rapidly corrode this normally $10,000 machine into uselessness and which is extremely hazardous to the health of people nearby. Yet Acrylic - which looks, smells, feels and tastes just like Lexan - cuts smoothly and cleanly and is one of the best materials to use with the laser! So check and double-check what you're cutting.

Where to Find Materials

There is a fairly good supply of materials at the hackerspace, which you can pay for in the store. If you need larger quantities or a unique material, you can try one of the places listed here:

Where to find materials to feed the laser.

NEVER CUT THESE MATERIALS

WARNING: Because many plastics are dangerous to cut, it is important to know what kind you are planning to use. Make has a How-To for identifying unknown plastics with a simple process.

Material	DANGER!	Cause/Consequence
PVC (Poly Vinyl Chloride)/vinyl/pleather/artificial leather	Emits chlorine gas when cut!	Don't ever cut this material as it will ruin the optics, cause the metal of the machine to corrode, and ruin the motion control system.
Thick ( >1mm ) Polycarbonate/Lexan	Cuts very poorly, discolors, catches fire	Polycarbonate is often found as flat, sheet material. The window of the laser cutter is made of Polycarbonate because polycarbonate strongly absorbs infrared radiation! This is the frequency of light the laser cutter uses to cut materials, so it is very ineffective at cutting polycarbonate. Polycarbonate is a poor choice for laser cutting.
ABS	Melts / Cyanide	ABS does not cut well in a laser cutter. It tends to melt rather than vaporize, and has a higher chance of catching on fire and leaving behind melted gooey deposits on the vector cutting grid. It also does not engrave well (again, tends to melt). Also, cutting ABS plastic emits hydrogen cyanide, which is unsafe at any concentration.
HDPE/milk bottle plastic	Catches fire and melts	It melts. It gets gooey. Don't use it.
PolyStyrene Foam	Catches fire	It catches fire, it melts, and only thin pieces cut. This is the #1 material that causes laser fires!!!
PolyPropylene Foam	Catches fire	Like PolyStyrene, it melts, catches fire, and the melted drops continue to burn and turn into rock-hard drips and pebbles.
Epoxy	burn / smoke	Epoxy is an aliphatic resin, strongly cross-linked carbon chains. A CO2 laser can't cut it, and the resulting burned mess creates toxic fumes ( like cyanide! ). Items coated in Epoxy, or cast Epoxy resins must not be used in the laser cutter. ( see Fiberglass )
Fiberglass	Emits fumes	It's a mix of two materials that cant' be cut. Glass (etch, no cut) and epoxy resin (fumes)
Coated Carbon Fiber	Emits noxious fumes	A mix of two materials. Thin carbon fiber mat can be cut, with some fraying - but not when coated.
Any foodstuff ( such as meat, seaweed 'nori' sheets, bread, tortillas... )	The laser is not designed to cut food, and people cut things that create poisonous/noxious substances such as wood smoke and acrylic smoke.	If you want to cut foodstuffs, consider sponsoring a food-only laser cutter for the space that is kept as clean as a commercial kitchen would require.

Safe Materials

The laser can cut or etch. The materials that the laser can cut materials like wood, paper, cork, and some kinds of plastics. Etching can be done on almost anything, wood, cardboard, aluminum, stainless steel, plastic, marble, stone, tile, and glass.

Cutting

Material	Max thickness	Notes	WARNINGS!
Many woods	1/4"	Avoid oily/resinous woods	Be very careful about cutting oily woods, or very resinous woods as they also may catch fire.
Plywood/Composite woods	1/4"	These contain glue, and may not laser cut as well as solid wood.
MDF/Engineered woods	1/4"	These are okay to use but may experience a higher amount of charring when cut.
Paper, card stock	thin	Cuts very well on the laser cutter, and also very quickly.
Cardboard, carton	thicker	Cuts well but may catch fire.	Watch for fire.
Cork	1/4"	Cuts nicely, but the quality of the cut depends on the thickness and quality of the cork. Engineered cork has a lot of glue in it, and may not cut as well.	Avoid thicker cork.
Acrylic/Lucite/Plexiglas/PMMA	1/2"	Cuts extremely well leaving a beautifully polished edge.
Thin Polycarbonate Sheeting (<1mm)	<1mm	Very thin polycarbonate can be cut, but tends to discolor badly. Extremely thin sheets (0.5mm and less) may cut with yellowed/discolored edges. Polycarbonate absorbs IR strongly, and is a poor material to use in the laser cutter.	Watch for smoking/burning
Delrin (POM)	thin	Delrin comes in a number of shore strengths (hardness) and the harder Delrin tends to work better. Great for gears!
Kapton tape (Polyimide)	1/16"	Works well, in thin sheets and strips like tape.
Mylar	1/16"	Works well if it's thin. Thick mylar has a tendency to warp, bubble, and curl	Gold coated mylar will not work.
Solid Styrene	1/16"	Smokes a lot when cut, but can be cut.	Keep it thin.
Depron foam	1/4"	Used a lot for hobby, RC aircraft, architectural models, and toys. 1/4" cuts nicely, with a smooth edge.	Must be constantly monitored.
Gator foam		Foam core gets burned and eaten away compared to the top and bottom hard paper shell.	Not a fantastic thing to cut, but it can be cut if watched.
Cloth/felt/hemp/cotton		They all cut well. Our lasers can be used in lace-making.	Not plastic coated or impregnated cloth!
Leather/Suede	1/8"	Leather is very hard to cut, but can be if it's thinner than a belt (call it 1/8"). Our "Advanced" laser training class covers this.	Real leather only! Not 'pleather' or other imitations!
Magnetic Sheet		Cuts beautifully
NON-CHLORINE-containing rubber		Fine for cutting.	Beware chlorine-containing rubber!
Teflon (PTFE)	thin	Cuts OK in thin sheets. See https://www.ulsinc.com/materials/teflon ; the issues listed in https://en.wikipedia.org/wiki/Polymer_fume_fever. Our laser cutter has ventilation but does not seem to exhaust everything so be extremely careful.
Carbon fiber mats/weave that has not had epoxy applied		Can be cut, very slowly.	You must not cut carbon fiber that has been coated!!
Coroplast ('corrugated plastic')	1/4"	Difficult because of the vertical strips. Three passes at 80% power, 7% speed, and it will be slightly connected still at the bottom from the vertical strips.

Etching

All the above "cuttable" materials can be etched, in some cases very deeply.

In addition, you can etch:

Material	Notes	WARNINGS!
Glass	Green seems to work best...looks sandblasted.	Only FLAT GLASS can be engraved in our cutter. No round or cylindrical items.
Ceramic tile
Anodized aluminum	Vaporizes the anodization away.
Painted/coated metals	Vaporizes the paint away.
Stone, Marble, Granite, Soapstone, Onyx.	Gets a white "textured" look when etched.	100% power, 50% speed or less works well for etching.

External Resources

• List of Materials that can be laser cut