Laser Cutting

 WEEK 2(Tutorial)

In week 2’s lesson, we were introduced to laser cutting. Laser cutters are machines that use motors controlled by a computer to cut and engrave material using a laser beam. In SP FabLab, carbon dioxide (CO₂) laser cutter machines are used.

 

CO₂ laser cutter machines are simply machines that use carbon dioxide laser technology to cut and engrave materials. A CO₂ laser cutter is able to cut through materials such as wood, acrylic, cardboard, and paper.

 

Operating a laser cutter does come with some safety hazards. Here are some things you should avoid when operating a laser cutter:

•  Avoid staring into the beam during cutting
• Do not use materials that contain chlorine, for example PVC, or foam.
• Do not cut or engrave metal materials
• Never leave the machine unattended while cutting or engraving

 Other safety measures to note are:

•  In the event a small fire occurs, attempt to extinguish it by blowing it or removing the material from the laser cutter
•  If the material is unable to be cut through, stop work, and check the focus lens, which might be dirty. A dirty lens may result in a cracked lens if it is used continuously despite being dirty.

 

To laser cut our designs, they must first be saved as either Raster or Vector files. The difference between these two file types is shown below.

 

Raster images:

• uses pixel resolution that use colour and tone to produce an image
• file format: GIF, JPG, BMP, PNG, TIFF
• pixels appear like little squares on graph paper when the image is zoomed in or enlarged
• created by the digital camera, scanning into the computer or raster-based software

Vector images:

• uses scalable resolution
• file format: EPS, SVG, AI
• graphics consist of anchored dots and connected by lines and curves, similar to the connect-the-dot activities

Figure 1: Vector vs Raster image (Shutterstock, 2018)

References

Shutterstock.com. 2021. [online] Available at: <https://www.shutterstock.com/blog/wp-content/uploads/sites/5/2018/02/Vector-vs-Raster_Featured-Image.jpg> [Accessed 31 October 2021].

1000logos.net. 2021. Punisher logo and symbol, meaning, history, PNG. [online] Available at: <https://1000logos.net/punisher-logo/> [Accessed 31 October 2021].

WEEK 4(Practical)

  For the practical in week 4, we went T11C FabLab to experience operating the laser cutter machine. As part of our pre-practical activity, we were required to develop a Standard Operating Procedure (SOP) for operating the laser cutter machine. However, during the competency test and practical, we realised that there were several key steps that was not included in our original SOP. Therefore, the revised and updated SOP is shown below.

Updated Laser Cutter Standard Operating Procedure

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

 2.1. 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.

 

2.2. General/ Personal Safety

•         Make sure the material thickness is no thicker than 5mm as the laser cutter cannot cut deeper than that.
•         Make sure the material thickness is no thicker than 5mm as the laser cutter cannot cut deeper than that.
•         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.

 

2.3. 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

3.1. Start-up

Step 1: Turn on the air compressor (red switch). Do note that this step is only for the Epilog M2 machine. As for the Epilog Pro, the air compressor is installed within the machine, hence it does not need to be manually switched on. 

Figure 5: Air Compressor

Step 2: Turn on the fume extractor (Green button for Epilog M2, Power button for Epilog Pro)

Figure 6: Fume Extractor

Step 3: Turn on the on/off switch (Black switch for Epilog M2, turn key for Epilog Pro)

 

Figure 7: On/Off Switch for Epilog M2

Figure 8: On/Off Key for Epilog Pro

Step 4: While waiting for the laser cutter to finish the initialisation process, head over to the workstation to send the 3D drawing to the laser cutter.

3.2. Operation

Step 1: Use Vernier Callipers to measure the thickness of the material

 

Step 2: Open the imported SVG or DXF 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.

 

     Table 1: Summary of CorelDraw functions

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 Epilog M2, “Auto Focus” must be set to “ON”, while for Epilog Pro, it must be set to “Thickness”.

 

Step 6: Turn on “Air Assist”. Do note this is for Epilog M2 only.

 

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.

Table 2: Summary of Epilog Dashboard Functions

	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

3.3. Shutdown

Step 1: Once the laser cutter machine has cooled down, turn off the on-off switch.

Step 2: Switch off the fume extractor.

Step 3: For Epilog M2, switch off the air compressor.

Step 4: Clean up the interior of the laser cutter machine, as well as the surrounding area. Ensure that there is no dust or scrap materials left behind.

CorelDraw

Import the file containing the design file to be cut into CorelDraw as a DXF or SVG file. On the new interface, we can select which parts will be cut or engraved.

Figure 9: CorelDraw Interface

The guidelines for cutting or engraving a part can be found in Table 1 above.

After the parts to be cut or engraved have been selected, the file can be sent for printing

Figure 10: Sending the File for Printing

After the file has been sent for printing, a new interface in Epilog will pop up.

Epilog Dashboard

Ensure auto focus and air assist are turn on. At the right side of the interface, input the thickness of the material into the software.

Figure 11: Auto Focus

Figure 12: Air Assist and Material Thickness

Double-check that the process of each object's action is correct. The Epilog Dashboard functions for cutting or engraving a part can be found in Table 2 above.

Figure 13: Cutting and Engraving

Upload the material settings by importing it from the Material Library.

Figure 14: Material Library

Load the material into the laser cutter machine.

Figure 15: Laser cutter Machine Interior

Send the file to the laser cutter machine for printing. Check that the name on the laser cutter display screen is the same as the file name on the Epilog dashboard and take note of the estimated time required for cutting

Figure 16: Sending the File for Printing

 

Figure 17: Confirming the Print on the Laser Cutter

Once the laser cutting process has concluded, allow the product to rest inside the laser cutter machine for 1 minute.

Practical

For this practical, we designed a parametric model to be laser cut in Fusion 360. Our original design was that of a birdhouse.

Figure 18: Original Birdhouse Components Design

 

Figure 19: Original Birdhouse Parameters

 

 

However, due to an issue with the angle and length of the roof, we were unable to cut this design, so we decided to cut something that was simpler, which was a wooden storage chest.

 

Figure 20: Wooden Storage Chest Components Design

Figure 21: Wooden Storage Chest Parameters

During the laser cutting process, everything went smoothly, as we had already taken the laser cutting competency test and had an idea of what to do.

 

 

Figure 22: Cutting Process

Figure 23: Final Product

Figure 24: Team Leader Nick with Final Product

However, when our final product was cut, we found that the connection between the pieces was not tight enough, and they would fall apart easily. This was due to kerf, which we had forgotten to take into consideration during the design process. In order to reduce the effect of kerf on the fit of the pieces, we can change the parametric values to be slightly bigger. This could potentially make the pieces fit better overall.

 

In general, this practical allowed me to understand how to use a laser cutter machine. I was fortunate enough to use both the Epilog M2 and Epilog Pro machines, hence I was abke to see the differences between the operation of these 2 machines. The practical definitely did boost my confidence in using a laser cutter machine, and I am confident that I am now able to operate it. In the future however, I will take into consideration the kerf when designing my object to be laser cut.