Laser Cutters

From Invention Studio
Jump to: navigation, search
Laser cutter in operation.

The laser cutter is a fast and convenient 2D cutting tool. We currently have three Trotec Speedy 300 laser engravers in room 2211 of the MRDC. Two of them (Banana and Cantaloupe) each have 140W tubes and one (Avocado) has a 40W tube.

Trying to use Banana? Check out the guide on Job Control X at the bottom of the page!

Trying to use Dragonfruit over in the Montgomery Knight branch? Check out the Epilog Guide at the bottom of the page!

How To

In general:

1. Take a DXF file.

2. Open in Inkscape or other program.

3. Print to the laser cutter software (JobControl).

4. Adjust material settings in JobControl.

5. Place material in laser, adjust bed height.

6. Do a test cut to check settings for materials.

7. Cut!

This is also good help if you need it: http://www.instructables.com/id/10-Tips-and-Tricks-for-Laser-Engraving-and-Cutting/

Capabilities

The laser cutter can cut 2D profiles and engrave 2D reliefs in a limited set of flat materials. It can also engrave on round surfaces using the rotary engraving attachment. There are materials which are not safe to use on the laser cutter, or which do not machine effectively in the laser cutter.

Cut Settings

[Google doc]

Materials

Note: If the material you want to cut isn't listed on this page, ask a Prototyping Instructor. They probably know the correct answer, or can direct you to someone that can help.

Material Safe to use with a laser cutter? Can you cut it? Can you engrave it?
Acrylic Safe! Yes Yes
Wood Safe! Yes Yes
Paper/Cardboard Safe! Yes Difficult
Steel Safe! No Yes (oxidize)
Titanium Safe! No Yields a rainbow of colors depending on power.
All other metals Safe! No Yes, if you use Cermark or other marking chemical.
Glass Mostly safe, don't breathe the glass dust. No Yes
Nylon Not recommended. Discoloration, low cut quality. Melts, doesn't engrave well.
ABS Not recommended. Discoloration, low cut quality. Slight engraving marks.
Polyethylene Not recommended. No. Lots of melting. Slight marks with melting.
Lexan/polycarbonate Black smoke and awful smell. DO NOT CUT. No No
PVC Creates Chlorine Gas. DO NOT CUT. No No
Vinyl Toxic fumes. DO NOT CUT. No No
Teflon/PTFE Toxic fumes. DO NOT CUT. No No
CF/Carbon Fiber DO NOT CUT. No No


Unknown materials, need to be added to the above table:

  • Fiberglass

Usage reference

Safety Information

Before using the laser cutter, be sure you understand the following safety rules. These rules are in place to protect both you and the laser cutter from injury.

  1. NEVER leave the laser running unattended. There should always be a person in the room watching the laser cutter while it is running. NO EXCEPTIONS!
  2. Small sparks and smoke are okay, but large flames are BAD. Do not continue a cut if it is creating large flames. Fire is a huge risk to the laser and its ventilation system. Stop your cut immediately and switch to a lower power setting.
  3. Check to make sure that the material you are using is in the allowed list of materials. If you aren't sure, DON'T CUT IT. Ask a Prototyping Instructor for help.
  4. Before cutting, ensure that there is no risk of the lens housing (the orange part that moves) colliding with any objects on the honeycomb table.

Preparing your files

  1. Documents type:
  2. Exporting your files:
  3. Document size:
  4. To create a design for cutting/engraving:

Turning on the Laser Cutter and Ventilation Systems

To turn on one of the laser cutters follow these steps:

  1. Locate the power supply for the ventilation system, it is on the wall to the left of the Waterjet power supply. Move the lever to the 'ON' position, and set the black dial to the 'HAND' position.
  2. Locate the connection between the laser exhaust and the main ventilation shaft. Make sure the panel blocking that connection is open.
  3. Turn on the cooling system by turning the red handle on the back corner of the cooling unit.
  4. Turn on the laser cutter using the black power switch on the back corner of the case.
  5. Open the shutter on the laser.

Connecting the Computer to the Laser

  1. Open up the JobControl software on the computer next to the laser (If it's your first time logging, you'll probably have to enter the software key. It is located in a DVD case in the black cabinet above Avocado).
  2. Near the bottom right corner, find and click the "connect" button.

Note: If you are unable to connect, power off and on the laser, try again. Note 2: If you are still unable to connect, restart the computer.

Lenses

There are three lenses of different focal lengths that can be changed out by a Prototyping Instructors: red, black, and blue. The focus is set using the focal probe with the matching color (the red and black lenses can use the same focal probe).

Lens Focal length For cutting thicknesses Nosecone Position Nominal cut width
Red Short (38.1 mm) <1 mm Small Below 25μm
Black Medium (50.8 mm) <10 mm Small Above XXμm
Blue Long (Xmm) >10 mm Large Above XXμm

See the document at the bottom of the page for instructions on how to change the lenses.

Focus

To focus the laser:

  1. Hook the brass retention plate of the correct focus probe onto the lower right lip of the laser head. The probe will now be hanging with the "fins" pointing down.
  2. Raise the bed of the laser using the control pad until the probe touches the material to be cut and falls off the laser head.

Rotary attachment

Rotary attachment used to etch onto a glass.

The lasers can take a rotary engraving attachment to rotate round objects about while the laser scans along the axis.

Tips and Tricks for Better Results

General Advice:

  • Always bring extra material to run a test cut or engraving before making your finished part, so you can ensure that all of your laser settings are good.
  • Every material has optimal settings to get the best cut and engraving quality. Consider doing multiple tests at different powers to figure out the best settings for your material.

Cutting:

  • If you are cutting multiple large parts out of thick wood or acrylic, consider making those parts out of cardboard first. Cardboard can be cut much more quickly than wood. It's a fast check to confirm that all the parts are the size you thought they would be and that the laser is working correctly. This is very helpful for long cutting jobs or cuts done with expensive materials.
  • Small acrylic parts, especially tiny gears and other intricate parts, tend to heat up when cut. This can lead to warping or melting of your part. Consider cutting these tiny pieces with multiple passes on a very low power, giving the acrylic time to cool between each pass. This prevents warping that could happen when the acrylic gets too hot.
  • Even though the lasers can technically power through thicker materials in a single pass, that's not always the best idea. Especially with wood, you'll get better cut quality and less charring if you do a few lower-powered passes at a higher speed, instead of a single high-powered one.

Engraving:

  • When engraving text, consider adding a cut line that traces the border of each engraved letter. Keep it at a low enough power that it doesn't cut through your material. This gives your engravings a very clean edge and makes text much easier to read.
  • Engraved wood can have huge variation in color and surface finish, depending on the type of wood and what laser settings you use. Do a couple of test engravings to figure out which settings you like best.
  • As an alternative to engraving, making cut lines with the laser out of focus (table too low) can be a quick quick way to add engraved marks if you're trying to make simple lines or shapes on your project. Because the laser is out of focus, the 'cut' lines mark the wood in a similar way that engraving would, which can be done significantly faster than a real engraving of similar size.

Troubleshooting

General

Laser cutter not cutting

  • Check to see if the Shutter is open. The shutter is a switch, located on the back of the laser engraver.

Cut is out of focus even though I focused it

  • If it is in focus where you focused it, make sure the honeycomb is seated properly and that your material is not warped.
  • If the bed moves down when you press play, make sure that in the power/speed settings the z offset is zero. (Do not change the z offset to anything other than zero without talking to a ULI, or bad things could happen.)

JobControl

My job doesn't show up

  • Select "Job type" and "Resolution" (above the job list) to be "ALL."
  • Wait a moment; sometimes jobs do not show up instantly.

I can't position my job on the plate

  • Your job may be padded with blank space, making it larger than it should be. Reprint from your application with "Minimize to job" selected in print properties.
  • Your job may be of a different type or resolution of the job(s) currently on the plate. Delete the other job(s) on the plate.
  • There may not be any room on the plate. Make room by removing other jobs or making your job smaller.
  • If your job is close to the size of the plate, make sure when dragging your job to release your cursor near the top-left corner of the plate (but not off the plate). If the job hangs off the plate, the positioning will fail as if it doesn't fit.

My job doesn't preview properly

  • If it is grayed out, click the "WYSIWYG" button.
  • If colors are missing, you may have them set to "Skip." Go to Settings > Material properties (or Ctrl+M) and make sure they are set to engrave or cut.
  • Your colors may have been set incorrectly. Make sure that their RGB values have not been modified in the program you are printing form. For example, cut lines must be pure red i.e., (255, 0, 0) in RGB.
  • When engraving, JobControl will not display the raster images at full resolution. Try a test engrave on a piece of scrap, as it may be fine when it prints.
  • If your engraving doesn't show up at all, make sure "Vector job" is not checked in the print properties.
  • Some programs may have additional settings that can mess stuff up. EngraveLab, for example, has a "send all as vectors" option in its dialog box which should be left unchecked.

My job is the wrong size, or was cut off

  • With more complicated jobs, "Minimize to job" can possibly mess up. You can try putting a box around it of an unused color, or uncheck "Minimize to job."
  • Check this same field under the program you are using's troubleshoot.
  • You may have the wrong width and height in the print properties dialog box. Correct them and make sure "take from application" is not checked.

EngraveLab

My exported .svg from EngraveLab is invalid.

  • On line 9 column 12 (right before stroke) you need to add the double quotes character (").

Adobe

My cut lines aren't working

  • In the advanced print options, make sure that "send as image" is not checked.

Inkscape

My job is the wrong size, or was cut off

  • In Inkscape anything above or to the left of the top left corner of your drawing will be cut off.


AutoCAD

  • It is generally recommended that you use SolidWorks (available through OIT) rather than AutoDesk products, because the latter do not generate files highly compatible with the Trotec software.

Avocado

Cut power too low

  • This laser is only 40W as opposed to the other 140W lasers, you will need to increase the power or decrease the speed

Cuts are off

  • As of 2014-3-10 there are some issues. I suggest using Banana if you need really high precision.

Links