Laser Cutting

Contents:

Week 2: Introduction to laser cutting

1. How does it work?
2. Hazards when operating the machine
3. Raster vs Vector
4. What is Kerf?

Week 4: Laser Cutting Practical

1. Improved SOP
2. Laser cuttings from competency test
3. Laser cutting from parametric construction kit
4. Reflection on Laser Cutting Experience
   

1. How does it work?

For this week's lesson, we were introduced to the interesting world of laser cutting. You might be wondering what is a laser cutter machine? It is as its name applies, it is another cutting tool that directs a highly intense laser beam with a specific focal length onto a material to either cut or engrave. There are many different types of laser cutters, however, the one we are focusing on today is the one available at the FABrication Lab, the CO2 laser cutting machines that uses carbon dioxide lasers to cut or engrave materials like wood, acrylic, cardboard and paper.

Below is a diagram on how the CO2 laser cutting machine works:

As shown in the diagram, the laser cutter is able to move along in both the X and Y-axis. This is possible due to the 3 mirrors next to the CO2 tube, the hinge holding the laser cutter and inside the laser cutter itself, reflecting the laser beam onto the product. 

Both the air compressor and the fume extractor in the exhaust are essential when operating the laser cutter and must be turned on every time. The fume extractor is used to extract harmful gases and debris and filter them out before the air is released into the atmosphere. The air compressor uses compressed air to blow debris off the board and also to put out small fires when using the laser. 

2. Hazards when operating the machine

Before operating the laser cutting machine, users must be aware and briefed on the safety hazards. Some examples of safety hazards are:

1. Avoid staring into the beam while cutting
2. Do not use materials that contain chlorine or foam (eg. PVC)
3. Do not cut or engrave Metal
4. Do not leave the machine unattended while cutting/engraving
5. If a small fire occurs, attempt to extinguish it by blowing it or removing material from the laser cutter
6. If the material cannot be cut through, check if the focus lens might be dirty. Repeated use of the dirty lens will result in the cracked lens

3. Raster vs Vector

What are Vectors? 

Vectors graphics consists of anchored dots and are connected by lines and curves. These graphics are scalable, meaning that they won't lose their resolution even when zoomed in. 

What are Rasters?

Raster images are made of pixels or tiny dots that use colour and tone to produce the image. Unlike vectors, they are not scalable. This means they will lose their resolution when zoomed in and the pixels will appear like little squares on graph paper.

4. What is Kerf?

To laser cut a tab to fit into a slot and have them join firmly, you need to make the tab or slot somewhat smaller in terms of dimensions so that they fit smoothly and not loosely. Kerf would be the amount burned away during this process.

Week 4: Laser Cutting Practical

1.Improved Standard Operating Procedure in the operation of laser cutter:

·       Procedure

a. Start-up

S/N	Steps/Description	Action
1	Ensure operators know where the fire extinguisher is.	Locate the nearest fire extinguisher
2	Check operators are in proper attire before operation: For neck, remove all collared objects. For hair, long hair is tied and clipped up. Full-covered shoes and long pants are worn.	-
3	Check laser cutting bed has no leftover debris.	If have, fully open the lid to 90°and clean it with a dust broom
4	Gently pull down the lid to close when done.	Check interlock light, ‘L’ and ‘R’ are lighted green.
5	Switch on air compressor from the back located at the side of machine.	Press ‘I’ or ‘II’ on the red switch
6	Switch on fume extractor/exhaust from the back located behind the machine.	Press the green button
7	Ensure lid is closed.	Check interlock light, ‘L’ and ‘R’ are lighted green
8	Switch on the laser cutter machine located in front.	Press ‘I’ on the black switch
9	Wait until the laser cutter machine finishes running the initialization process from the machine panel.	Machine panel shows ‘CO2 Fusion’
10	Place material on laser cutter bed.	Fully open the lid to 90°
11	Gently pull down the lid to close when done.	Check interlock light, ‘L’ and ‘R’ are lighted green
12	Proceed to the workstation to set drawing for the laser cutter machine.	-

 

b. Operation of laser cutter including the basic use of Corel-Draw

S/N	Steps/Description	Action
1	Run Coreldraw	Click on the desktop app
2	Open the file that is going to be cut out/ engraved.	Click “File” → “Import”, then select the design to be laser cut
3	Adjust the size and position of the of your design	Drag and resize using cursor
4	Identify parts to cut or engrave. For cutting: Select the parts that are going to be cut out. Change the colour to RED and the width to “Hairline”.  Adjust colour settings to red  (R: 255, G: 0, B: 0). For engraving: Select the parts that are going to be engraved. Change the colour to GREEN and fill the whole shape with green.  Adjust colour settings to green  (R: 0, G: 255, B: 0).  then, click on the green colour on the bottom left of the screen to fill.	Open the “Outline Pen” tab by double clicking at the bottom of the screen to change colour and width.
5	Send file to Laser cutter	Click the “Print” icon, the 4th icon at the top left of the screen
6	Adjust the position and size of the selected design in Coreldraw by following the ruler	-
7	Set Auto Focus to “ON” (for Epilog M2 Machine) or “THICKNESS” (for Epilog Pro Machine)	Click the button beside or below the word “Auto Focus”
8	For engrave: Adjust speed to 20%, power to 85% and frequency to 85% For vector: Adjust speed to 10%, power to 80% and frequency to 80%	-
9	Measure the thickness of the material using a vernier calibre. Import material setting from the library For cutting: Click into the VECTOR tab and select the material that is being used For engraving: Click into the ENGRAVING tab and select the material that is being used.	Click “Import Material Settings”
10	For both vector and engraving: Set thickness to the thickness of the material being used.	Type in material thickness into the thickness tab
11	Set AIR ASSIST to ON for all processes.	Click button beside “Air Assist” from OFF to ON
12	PRINT out the design	Click on “Print” button
13	Verify if the correct file is sent. Take note of the time needed to cut/engrave material.	Look at the machine panel
14	Start cutting/engraving	Click the green “GO” button on the machine panel
15	When done, leave product in the machine for a minute.	-
16	Open the lid of the laser cutter machine and tap on the cut pieces of the material to remove the cut pieces.	Fully open the lid to 90°

 

c. Shutdown

S/N	Steps/Description	Action
1	Remove all finished pieces and materials. Check that there are no leftover debris and materials. Make sure there is nothing left on the laser cutting bed.	If there are any leftover debris, fully open the lid to 90°and clean it with a dust broom
2	Gently pull down the lid to close when done.	Check interlock light, ‘L’ and ‘R’ are lighted green
3	Switch off laser cutter machine located in front.	Press ‘O’ on the black switch
4	Switch off fume extractor/exhaust from the back located behind the machine.	Press the lighted green button
5	Switch off air compressor from the back located at the side of machine.	Press ‘O’ on the red switch
6	Perform Housekeeping. Do not leave anything on the computer table.	-

Reflection on the competency test:

All the additions to the standard operating procedure (SOP) are in Red. Since there wasn't much addition to the SOP, the competency test was relatively easy. There were minor additions like the engraving speed, colour settings and resizing that I did not mention in the SOP. But thanks to the demonstration by the lecturer, i was able to include the parts I have left out. Thus by following the corrected SOP, i was able to pass the competency test with relative ease

2. Laser cuttings from competency test

It is a small square with 'TEST' engraved on it

3. Laser cuttings from parametric construction kit

Sketches of our shapes in our construction kit:

Pre-planning:

Design in fusion:

Here is the final product:

My group's construction kit

My group's Christmas Tree

4. Reflection on Laser Cutting Experience

So far, I've found this practical to be one of the most interesting and valuable to me. Prior to this practical, I had heard from friends about their experiences using laser cutters in their schools and producing their own products for projects. I consider myself to be a highly creative person, therefore anything that sparks creativity is naturally very appealing to me. With this in mind, I was looking forward to the practical.

Prior to the practical, I was intimidated by the amount of information we needed to understand in order to run the machine. There were several safety protocols that had to be followed before to using the machine, such as turning on the fume extractor to filter the air and turning on the air compressor to avoid tiny fires and lens damage. I had to learn about how red lines represent cutting and green lines represent engraving, as well as how to adjust the laser's speed and power for optimum cutting.

With the assistance of the improved Standard Operating Procedure(SOP), I was able to pass the competency test on my first attempt. I frequently double-checked the SOP with my groupmates, afraid of missing any steps I had missed in the video. I was particularly nervous when operating the laser cutting equipment since I was afraid I might miss certain steps. Despite my concerns, I was able to perform well on the competence test.

There were a few hiccups when preparing the cutting the pieces from the parametric construction kit. Designing the components was a big challenge for me since the items we created were considerably more difficult to make than any of my previous projects. Also, because the parameters were estimated, most of the initial few parts were not sized appropriately and could not fit into one another during the actual laser cutting of the pieces. However, after some trial and error, we were able to find the ideal size.

Overall, this practical fulfilled my expectations in terms of testing my Fusion360 abilities and learning how to use something new. This practical helped me realize some of the things I was missing. For example, while I was creating the circular piece, I had to redo it three times using three different design methodologies I found on YouTube and Google. There were problems, such as being unable to evenly space out the slits on a circle. I had to then improvise by using a pentagon instead and smoothing out the edges to form a circle.

Despite the fact that there are many steps and knowledge of the laser cutter machine that I must learn and acquire before I can operate the machine, I believe that this is what makes this practical so intriguing and fun. There are many more features that I have yet to learn and master, and this is only in this mode of laser cutters. I'm looking forward to the day when I'll be able to operate far more complicated and larger laser cutters in large corporations with far more applications and functionalities.