Laser cutting

 

LASER CUTTING

For this week we did laser cutting and the objectives were to:

• explain how the laser cutter works
• the risks and hazards that comes with using a laser cutter
• name the materials that can be cut and how deep it can be cut
• explain the difference between raster and vector

So how does a laser cutter work? Specifically a CO2 laser cutter since that is the one we'll be using. It works by passing high voltage current through the tubes mainly filled with CO2 and some nitrogen which would increase the energy of the gas particles and produce an invisible beam of high power infrared light(laser beam). To move and redirect the laser beam, multiple mirrors would be use to reflect the laser beam to the focusing lens and onto the workpiece. The purpose of the focusing lens is to focus the beam into a small point making it more powerful like a magnifying glass. If the focusing lens is damaged or is too close or far from the focal point, the laser would not be able to cut the work piece properly.

This is an example of a CO2 laser tube

risks and hazards:

things that you should NOT do

• Stare into the beam while cutting
• Cut materials that contain chlorine or foam
• Cut or engrave metals (situational)
• Leave the machine unattended while cutting/engraving.

If a small fire occurs, attempt to extinguish it by blowing it or removing material from a laser cutter.

If the material cannot be cut through, stop and check to ensure that the focus lens is clean.

Suitable Materials

These are some materials we are able to work with in FabLab

• Wood(Plywood, Natural wood, and MDF up to 6mm)
• Acrylic (up to 5mm)
• Cardboard (burnt marks and fire may occur)
• Paper(Art card, Technical board)

Example of acrylic

Comparison of raster and vector graphics

Raster Graphics:

Composed of pixels

Cheaper

Occupy more space depending on the image quality 

File extensions: .BMP, .TIF, .GIF, .JPG

Vector Graphics

Consists of anchored dots and connected by lines

More expensive than raster graphics

Occupy less space

File extensions: .SVG, .EPS, .PDF, .AI, .DXF

1. Purpose

The purpose of this Standard Operating Procedure (SOP) is to describe the steps taken to operate the Epilog Laser Cutter Machine in the FabLab at T11C.

2. Safety

Materials

• Avoid cutting flammable materials to reduce the risk of fire. Avoid cutting metals. Also, do not use materials with chlorine or foam as they will release toxic gases when exposed to high temperatures.
• Make sure the material thickness is no thicker than 5mm as the laser cutter cannot cut deeper than that.

General/Personal Safety

• Do not lean over the cutter machine and stare into it when it is cutting. Staring into the laser while it is in operation can cause damage to the eyes.
• Never leave the laser cutter unattended when it is operating. If the power settings of the laser are too high, the laser will cut through the material and concentrate on the case bottom of the laser cutter. It may cause damage to the exterior of the case bottom, fry electronic components and even start a fire
• Do not have anything around the neck (e.g. lanyards) as it may cause the user to be entangled into the laser cutter. Long hair should also be tied up so that it does not get caught in the laser cutter machine.

Laser Cutter Machine

• Clean and vacuum the cutting deck and the internal cavity of the laser cutter regularly. Small particles of cut materials (e.g. sawdust) can ignite and cause explosions.
• When opening the laser cutter, make sure the cover is opened fully.
• Do not put your head inside the laser cutter when the cover is half-open.
• Do not slam the cover of the laser cutter. Instead, close the cover gently. Ensure that the interlocking light on the side panel is lit.
• Always check that the two LED lights on the side panel are on. This will tell us that the cover of the laser cutter is fully closed.

3. Procedure

a. Start-up

Step 1: Turn on the air compressor by pressing the red button

Step 2: Turn on the fume extractor by pressing the green button

Step 3: Press the on-off switch to turn on the laser cutter

while waiting for the laser cutter to set-up, go to the workstation to send the 3D drawing to the laser cutter.

b. Operation

Step 1: Use vernier calipers to measure the thickness of the material
Step 2: Open the imported DXF or SVG file in CorelDraw.
Step 3: Select the part to be cut/engraved/etched.

• For parts to be cut, the colour of the border should be red, and its line weight should be hairline.
• For parts that will be engraved, the colour of the border should be green, and the part to be engraved should also be filled green.
• For parts that will undergo scoring, the colour of the border should be green, and it should have a line weight that is hairline.

Jargon	Vector Cut	Engrave	Engrave Etch/Score
Colour	Red	Green	Green
Line Weight	Hairline	-	Hairline
Fill	-	Green	-

Step 4: Once the parts to be created have been selected, send the file for printing (top left corner, fourth icon).

Step 5: On the new interface, turn on “Auto Focus”. For the Epilog M2 machine, “Auto Focus” must be set to “ON”, while for the Epilog Pro machine, it must be set to “THICKNESS”.

Step 6: Turn on “Air Assist”.

Step 7: Import material settings to select the type of material that will be cut, and key in the thickness of the material.

For engraving, select “Engrave”.

For cutting, select “Vector”.

Step 8: Once complete, click “Print” (bottom right corner). This will send the file to the laser cutter.

Step 9: Load the material to be cut into the machine.

• For Epilog Fusion Pro, adjust the material such that it is being cut at empty spaces of material, to help save material.
• For Epilog Fusion M2, adjust the objects using the mouse tool on the left bar and adjust based on the location of the 2 rulers on the top and on the left.

Step 10: Check that the name on the laser cutter display screen is the same as the file name on the Epilog dashboard. Take note of the estimated time required for cutting.

Step 11: On the Epilogue Fusion M2 machine, press “Go” to start the cutting process. On the Epilogue Fusion Pro machine, press “Play”.

Step 12: Once the laser cutting process is complete, let it rest for 1 minute inside the laser cutter to let it cool down and allow the fume extractor to remove the toxic fumes produced from the process.

Step 13: Open the laser cutter and remove the cut material.

	Vector Cut	Engrave	Engrave Etch/Score
Settings	Use Material Library Folder		Set Process Type to VECTOR SPEED & POWER: Follow engraving values
Thickness	Depends on the material

c. Shutdown

1. once the laser machine has cooled down, turn the machine off with the on-off switch

2. Switch off the air compressor by pressing the red button.

3. Switch off the fume extractor by pressing the green button.