AEMS Laser Cutting Manual

The AEMS shop has two Laser Cutters available for use.

The Laser Cutter can handle the following materials: Acrylic, Glass, Laminates, Leather, Paper, Plastics, Stone, Textiles, and Wood. For more information, visit the Materials section.

Supervision

The lasers cutters must be supervised at all times during cutting. Users may not leave the lab while cutting and should remain attentive to what the laser is doing. Users who leave a laser cutter running unattended will immediately lose their laser cutting privileges.

Laser light radiation

The SP500 operates as a Class 2 laser when the lid is closed (normal operation.) A Class 2 laser does not pose any hazard for the skin or eyes, but operators should avoid staring at the laser beam for long periods of time.

This machine is capable of operating with the front and rear doors open, this is known as “pass through.” When the doors of the machine are open, the laser becomes a Class 4 laser. This is the highest hazard level for laser devices. Regular AEMS shop users may under no circumstances attempt to use the SP500 in this way. Pass through operation is restricted to AEMS staff or other users that have been specifically trained in Class 4 laser use and authorized by the University’s Laser Safety Officer.

Class 4 laser hazards include:

• Risk of direct radiation and indirect stray radiation that may cause damage to both the skin and eyes.
• Risk of fire or explosion if used improperly and the radiation strikes a flammable material.

Pinch points

The SP500’s gantry is able to be moved while the cover is open. Be aware of your finger and hand position while repositioning the gantry.

Fumes

Laser cutters vaporize the material they are cutting. Each laser is equipped with an external exhaust system which must be on while the laser is in operation. Not only can the fumes damage the machine internals, some materials can generate smoke that is hazardous to your health. With the exhaust on the user will likely be able to smell the fumes, but the concentration should be low enough as to not be hazardous. Note that some materials can produce fumes that can cause serious health concerns and could even be fatal. These materials are prohibited from being used on the laser cutters. See Materials for details on acceptable material types.

Fire

As the laser cutters work via vaporization, there is a chance that some materials may ignite during cutting. Most of the time, flame inside the machine is momentary and isolated to the cut point. If the flame is elsewhere, the user should be aware of the appropriate steps to take. If you feel at any time that attempting to extinguish the fire yourself poses a risk to your safety, immediately leave the room, close the door behind you and pull the nearest fire alarm.

In the event of a fire, determine the severity and act accordingly.

Small flame or embers

• Large sheets with embers can be removed from the laser and run under water in the sink located in the 3D Print lab, 1320A.
• Small flames can be extinguished by suffocating the flame under another sheet of material. Simply drop another flat sheet over the flames.

Moderate flame

• Turn off the laser exhaust
• Use the fire extinguisher to extinguish the flames

Severe flame

• Leave the room immediately and pull the fire alarm. Exit the building.

* CEE= Civil and Environmental Engineering Department

AutoCAD 2018

1. Ensure that any lines meant for cutting (or scoring) are set to a lineweight of “0.00.”
2. Colours must be standard. (ie. AutoCAD’s red colour vs. a custom shade of red)
3. Check for double lines using “PURGE” or “OVERKILL” commands.
4. Arrange your parts so that they fit on your material and into the bed. (49” x 28”)
5. Type “PLOT”, press ctrl+P, or click the print icon to begin.
6. Under plotter name, select “Trotec Engraver…”
7. Choose “User defined size” when prompted. Your page size should now be 49” x 28”.
8. Under plot area, choose window, then click and drag to select your parts. Make sure there is no plot offset. Plots are positioned in JobControl, window size shouldn’t matter.
9. Plot scale should be set 1:1. Ensure you’ve selected the correct units (metric or imperial.)
10. Plot should be set to landscape.
11. Press “OK” to send the file to Job Control.

Rhino 5

1. Ensure that any lines meant for cutting (or scoring) are set to a lineweight of “Hairline.”
2. Colours must be standard. (ie. Rhino’s red colour vs. a custom shade of red)
3. Check for double lines using “SelDUP” command.
4. Arrange your plots so that they fit on your material and into the bed. (49” x 28”)
5. Type “PRINT”, press ctrl+P, or click the print icon to begin.
6. Under Destination choose “Trotec Engraver…” and set Output colour to “Display Color.”
7. Under View and Output Scale, choose Top View and then select “Window’. You will be prompted to choose the print window. Position the window with the center grip and press enter. Part positioning within the window doesn’t matter, this can be changed in JobControl.
8. Make sure Scale is set 1:1 and in the correct units (metric vs. imperial)
9. Click print to send the file to Job Control.

Job Control

1. Job Control should open automatically when a file is sent to the laser.
2. Your file should appear in the Job Queue on the right of the screen. Double click, or click and drag to move it onto the bed.
3. Your file will come in as a grayed-out box. Click the “WYSIWYG” icon (eye) to display your file. Not all of your lines may immediately appear, they need to be turned on first.
4. Click the “Materials Template” icon on the upper toolbar or press ctrl+m. This will open the setup menu.
5. Set each colour you are using to either:
   1. Engrave — for etching anything with a thickness (text, image etc.)
   2. Cut — for vector cutting of zero-thickness lines
   3. Skip — for unused colours
   4. Positioning — displays the colour, but will not engrave or cut
6. Set Power, Speed, and PPI/Hz for each colour used. See “Laser Cutting Basics” for a description of each.
7. Passes should be set to “1.” Multiple passes risk material ignition.
8. Air Assist must be turned on. Disabling Air Assist will rapidly cause damage to the lens during cutting.
9. Z-Offset and Advanced are options that rarely, if ever, need to be used. Consult the official Trotec SP500 Manual for details.
10. Press OK to save your setting and return to the cut plate.
11. Press the “Connect” icon on the right of the screen to connect to the laser (laser must be on.)
12. Position your parts on the table by clicking and dragging. The crosshairs indicate the current laser position and are useful for lining up parts on materials.
13. The Connect icon will now be a “Play” icon. Click to begin cutting.
14. During cutting, the stop or pause icons can be used on either the machine or within the Job Control interface.
15. After cutting, right click your file. Job reset will allow the same file to be cut again. Remove job will move the file back into the queue and delete job will remove the file entirely. Please delete files you no longer need to avoid cluttering the queue.

Power ON

There is an ON/OFF key located in the SP500’s control panel. Under no circumstances should this key be removed from the machine. To turn the machine ON, turn the key clockwise ¼ turn. The SP500 will then go through its startup procedure. If the lid is open, the machine will wait for it to be closed before beginning the procedure which it must complete before use. Make sure the lid is closed when the machine is turned on.

Exhaust ON

It is critical that the exhaust be turned on whenever the laser is in use. Without the exhaust, all of the fumes and debris from the cutting will rapidly collect on the lens surface. This will inevitably cause the laser light to burn the buildup on the lens surface instead of passing through. Lens replacement costs due to the exhaust not being turned on will be charged to the user and are $750.

Lens check

Before every cut session and at minimum hourly during a session, the lens must be checked for debris build up. To check, unscrew the fixing ring and carefully remove the lens from the laser head. Inspect the lens and look for fogging or particulate build up. Only if the lens is dirty, proceed to cleaning. Otherwise, return the lens to the head and lightly tighten the fixing ring.

Lens Cleaning

Only clean the lens if it is dirty. Unnecessary cleaning will degrade the optical coatings on the lens and reduce its lifespan.

To clean, carefully apply 2-3 drops of cleaning solution to the lens. Tear off about 1/3^rd of a lens cleaning tissue and gently rub the lens using the tissue. Do not touch the lens with your fingers directly. One cleaning should be sufficient, but the process can be repeated if the lens is especially dirty. If there is damage on the lens that cannot be cleaned off, inform your supervisor immediately. They will determine if the lens can continue to be used or needs to be replaced. If you do not inform the supervisor, we will assume that the lens damage was caused by you, and you will be responsible for the damage.

Focus

The laser must be focused at the beginning of every session as well as whenever the material thickness changes. Each lens has an ideal height over the material, proper focus ensures the best possible cut quality and laser strength. Improper focus can lead to cut lines that are weaker and visibly wider than normal. If the laser is extremely out of focus there is a risk of fire.

The diagram below illustrates how laser focus works. The ideal height for the lens to be over the material is right in the center of “depth of focus” zone. If the lens is too high or low over the work (out of focus,) the wider part of the beam would be used with poor results.

To focus the laser, bring the laser head directly above your material on the bed using the X+Y movement arrows.

Hang the focal tool on the laser carriage as shown and carefully raise the table with the Z+ arrow until the focal tool contacts the material and falls off. Return the focal tool to where it belongs.

Shut Off

Simply turn the key counterclockwise and close the lid. Press the red button on the exhaust control to shut off the exhaust.

If you have any questions about laser cutting specific material types, please consult AEMS staff.

*Cast acrylic vs. extruded - Engraving in cast material yields a much nicer finish, but costs more

***Leather - Some types of leatherette contain PVC, please see the warning above.

Note on PVC — Polyvinyl Chloride is a fairly common type of plastic that under no circumstances should be cut with a laser or otherwise combusted. When burned, the chloride vaporizes into chlorine gas, which can be lethal. If you are not sure what type of plastic you have, do not cut it.

Laser cutting is a balance of 3 settings, Power, Speed, and PPI/Hz. The combination of these determines the result of your cut and will need to be adjusted depending on a number of factors. Material type, material thickness, desired cut type and aesthetics being the most important considerations. Using incorrect settings will likely result in wasted time and material, but in some cases can cause fires or other hazards to the operator and machine.

AEMS provides laser samples of common material types to aid the user in determining an appropriate range to begin cutting with. It is however up to the user to allot their own time and material to fine tune these settings to obtain their desired outcome.

Power — Ranges from 1-100%. Higher values will increase the strength of the cut.

Speed — Ranges from 0.1-100%. Higher values will decrease the strength of cut. Note that if your file include curves, the optimal speed range is between 3-6%. Setting higher speed while vector cutting curves will slow the machine down and cause the lines to appear segmented.

PPI — Pulses Per Inch, ranges from 500-1000. Only used during engraving and best described as a resolution setting, akin to dpi (dots per inch.) Higher values will increase resolution and also cutting strength.

Hz — Hertz, ranges from 1000-60000. Only used during cutting, the hertz setting changes the frequency of the laser. Higher values do not always equate to stronger cuts. Note the setting used on the sample card, it will be appropriate for the material.

Air Assist — Each laser has its own onboard air compressor which when used provides a jet of air onto the lens surface during cutting. The main purpose of this is to clear fumes and debris away from the lens and keep it cleaner longer. For Air Assist to be effective, the nose cone must be attached to the bottom of the laser carriage, which is the default setup in the AEMS. However, if Air Assist is turned off, the cone instead traps fumes and smoke next to the lens causing rapid buildup and lens damage. For this reason, Air Assist must always be turned ON.

Test — Do some testing. If you are doing a large amount of cutting, it is in your best interest to test for the optimal settings to use. If half of your parts are not cutting all the way through or the laser is cutting slower than it should be, you’re wasting time.

Cut inside first — Profiles that have other profiles within them (think donuts) should be cut inside first. If the outside is cut first and shifts after cutting, the inside profile may not be positioned correctly. The order of the colours within JobControl determine the cut sequence.

Masking tape — If surface fuming is undesirable, tape of the area around engravings or cut lines and then simply remove the tape after cutting. If you’re using acrylic with a film on it, leave the film in place until afterwards for the same reason. Tape can also be used to keep thin materials from moving inside the machine or to hold warped materials flat.

Use the correct lens — AEMS has both 2” and 5” lenses available. For cutting jobs on thicker materials, a 5” lens will perform better with less cut angle. For cutting thin materials or engraving, a 2” lens is preferred. Ask AEMS staff if you think you need the 5” lens.