Laser Cutting

 This week we learnt about laser cutting, about how it works, the dos and don'ts when using a laser cutter and the basics of CorelDraw. We were also assigned tasks where we have to design a handphone stand using parametric which we also learnt today (this can be found in the CAD tab) and to design, lasercut a parametric construction kit that can be assembled in multiple ways. 

A few weeks after this tutorial lesson, we will be having a practical on laser cutting. During that practical, we will be undergoing a competency test and will be printing out the parametric construction kit we designed.

The Contents of this post:

1. What I learnt from the lesson on Laser Cutting

  - How it works

  - Materials that can be cut

  - Things not to do to ensure safety when using the machine

  - Vector VS Raster

  - Kerf

  - Conclusion

2. Improved Standard Operating Procedure of a Laser Cutter

3. Photos of the Laser Cut Pieces

  -Photo of my piece from the competency test

  -Photo of the parametric construction kit my group and I had designed

4. Reflection on my Laser Cutting Experience

1. What I learnt from the lesson on Laser Cutting

Firstly, I learnt how the laser cutter works. The image above is a simple model about how a laser cutter works. This laser cutting machine uses carbon dioxide that becomes a laser beam to cut through the material. Before starting, the air compressor and exhaust has to be on. This is because the air compressor is what provides the cutting gas (carbon dionxide) and the exhaust helps to filter our harmful gas that was generated during the laser cutting so that no harmful gases are being released into the air. The laser beam generated from the carbon dioxide will be directed to the carriage through mirrors. The focus lens in the carriage helps to narrow down the laser beam to a specific spot on the material, which will help to engrave or cut the material. The air assistor blows out air onto the material to help clear away the excess material generated by the cutting or engraving.

Next is what materials can be cut by the laser cutter. Woodn acrylic, paper and cardboard are some of the suitable materials that can be cut by the machine. However, some of this materials comes with certain risks if you were to cut them. For example, when cutting cardboard, there is a possibility that a fire may occur and burnt marks may appear due to the laser cutting.

Thirdly is the things that one must not do when using the machine. Here are what you should not do:

1. Do not stare at the beam

2. Do not use materials that contain chlorine or foam (e.g Polyvinyl Chloride) 

3. Metal materials should not be cut or engraved

4. Never leave the machine unattended when it is in the middle of cutting/engraving

5. If small fire occur, attempt to extinguish by blowing it or remove material from laser cutter

6. Stop and check if the machine has difficulties cutting as it might be a case of dirty focus lens (Continued use of said dirty focus lens might result in crack lens that has to be replaced and they are not cheap)

Next is the difference between Vector and Raster. To start laser cutting, you will need to imput the file of your design and this file can come in either Vector or Raster files. So what is the difference? 

Vector graphics:

- uses anchored dots that are connected by lines and curves to produce a scalable graphic

- when scaled up, it will still look exactly the same as before, just bigger

Raster images:

- uses pixels or tiny dots that use colour and tone to produce an image

- when scaled up, it will look very pixelated  (like little sqaures)

This image shows the the difference when an image is scaled up. 

Lastly, what is kerf? Kerf is the amount of material that was burnt away during the process of laser cutting. Therefore if you want to laser cut a tab to put it into a slot and have them connect tightly, you may have to make the tab or slot slightly smaller in terms of their dimensions so as to have them fit nicely and not loosley.

Conclusion:

Overall, I found this lesson very interesting as this is something that is new to me. It is actually quite amazing how carbon dioxide can become a laser beam that can actually cut through materials. Although, learning the basics of how this machine works and the dos and don'ts when using this machine was quite simple, I found the part where we have to use a programme called CorelDraw before we can start laser cutting very confusing and difficult. Perhaps because it was fairly new to me and that there were a lot of functions in it. However, I hope that I can clear my confusions and familiarise myself with the process of using the machine during the practical session.

2. Improved Standard Operating Procedure of a Laser Cutter

a. Start-up

S/N	Steps/Description	Action
1	Locate and be aware of any nearby fire extinguishers .	-
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. (Make sure main power socket is on as well)	Press ‘I’ or ‘II’ on the red switch
6	Switch on fume extractor/exhaust from the back located behind the machine. (Make sure main power socket is on as well)	Press the green button
7	Switch on laser cutter machine located in front.	Press ‘I’ on the black switch
8	Wait until the laser cutter machine finishes running the initialization process from the machine panel. When laser cutter is still running the initialization process: When laser cutter is ready to be operated:	Machine panel shows ‘CO2 Fusion’
9	Place material on laser cutter bed.	Fully open the lid to 90°
10	Gently pull down the lid to close when done.	Check interlock light, ‘L’ and ‘R’ are lighted green
11	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 the CorelDraw programme.	-
2	Open the file that is going to be cut out/ engraved.	Click “File” → “Import”, then select the design to be laser cut
3	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”. For manual input of colour : 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. To fill the whole shape, click on the green square at the bottom left of the screen. For manual input of colour: R:0 G:255 B:0	Open the “Outline Pen” tab by double clicking onto the icon at the bottom of the screen to change colour and width
4	Send file to Laser cutter	Click the “Print” icon
5	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”
6	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”
7	For vector and engraving: Measure thickness and set thickness to the thickness of the material being used.	Use a vernier caliper to measure the thickness and type in material thickness into the thickness tab
8	Add in the following details: For vector: Speed = 10% Power = 80% Frequency = 80% For engraving: Speed = 20% Power = 85% Frequency = 85%	-
9	Set AIR ASSIST to ON for all processes.	Click button beside “Air Assist” from OFF to ON
10	Adjust the size of the design to the wanted size and the position of the design according to the space available on the material	Look at the material on the laser cutter bed and compare with the computer screen
11	PRINT out the design	Click on “Print” button
12	Verify if the correct file is sent. Take note of the time needed to cut/ engrave material.	Look at the machine panel
13	Start cutting/engraving	Click the green “GO” button on the machine panel
14	When done, leave product in the machine for a minute.	-
15	When all harmful gas has been extracted and the product has cooled down, tap the product to separate the product from the leftover product and check if everything was completely cut through.	Fully open the lid of laser cutter to 90° and tap on product
16	If the product cannot be separated after tapping, repeat from step 11 onwards.	-

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.	-

The words in blue are the corrections done to the original standard operating procedure (SOP). There was no major changes or any wrong steps in the original SOP but after checking with the lecturer, more steps were added to give more details on using the laser cutter. Most of the changes or almost all of them were new things that we learnt when the lecturer demostrated or when we asked the lecturer. In the future if any of my groups project needs to use a laser cutter, we can use this edited SOP without any worries. This is because we have testeed it out and improved it based on our experiences.

3. Photos of the Laser Cut Pieces

The following picture is the piece I laser cut for my competency test. It looks a bit weird as I did not align the "TEST" word properly in the centre of the piece.

Next are the pictures of my groups parametric construction kit:

All the pieces that was laser cut.

This a christmas tree we made from the construction kit.

4. Reflection on my Laser Cutting Experience

In our practical this week, we got a chance to experience operating a laser cutter. Using the laser cutter, we did a compentency test and afterwards, used the machine to cut out our construction kit. 

For the competency test, we were going to be examined on our compentency to start, operate and shut down the laser cutter machine. For starting the machine, we had to turn on all the relevant side equipment that will aid the laser cutter with the cutting. Machines like the air compressor and fume extractor. We also had to be aware of the nearest fire extinguisher in case of emergencies where there is a fire needed to be extinguished. To operate the machine, we had to know how to import the file into CorelDraw. After importing we had to specify all the details according to the parts to engrave/cut, material to cut and location of cut. When all that is done we can start cutting or engraving using the laser cutter.

As it was my first time operating a laset cutter, I was very nervous for the competency test. However, there was a brief demostration done to ensure we knew the basic steps. During that demostration, I cross-checked what was shown with the SOP I did with my group. If there was anything missing, I would write it down to remind myself to add it in into the SOP to make the SOP more complete. While I was doing the test, I realised its importance in teaching us. As during the test, we had to laser cut out a design all by ourselves with no help from the lecturers. This really tested my knowledge I have learnt on laser cutting. Through this test, it helped to highlight the little details I missed. For example, before importing the file and laser cutting the deisgn, I failed to check whether the laser cutter bed has any remaining materials from the previous use. This was something I will not have realised if not for the test. Additionally, I also did not know that we could tap on the finished laser cut pieces to check whether it was properly cut all the way through. Instead, I pulled out the whole piece of material before seperating the laser cut piece from the remaing material. This action should be avoided, this is because in a scenario where after pulling out the material, I realised that the piece was not fully cut out, I would have to put everything back onto the laser cutting bed to recut. As I have moved the material previously, during laser cutting it could cause the cut to be not on the same cut from before. Therefore, I was advised to tap on the pieced instead of pulling everything out to check.

After the competency test, we were given time to cut out our construction kit we designed in our groups. This too was without guidance from the lecturers so it was up to ourselves on how we want to laser cut our design. Before coming for the practical, we had to design the different parts and sketch the design in Fusion 360. The following pictures are the sketches we did before settling on a few shapes.

 

 

 

 

The greatest challenge we faced was that since it is a construction kit, there should be multiple different shapes and objects that can be made from the different pieces. However since our main idea was a christmas tree, it was quite difficult to come out with other shapes that can be formed. After much considerations, we settled on the contruction kit being able to also make a lantern. Finalising a few shapes to form actually helped us in deciding the different shapes to laser cut out.

On the day of the practical, we went ahead with the previously agreed shapes. The shapes had been drawn on Fusion 360 using parametrics and transferred to a thumbdrive to insert into the computer that is connected to the laser cutter. On our first try, we decided to first print out the traingle shapes. Since it was out first time, we did not pay much attention to the slots or size. When the triangles were cut out, we moved on to cut out the petal like circle shapes. This was where the trial and error starts. When we first cut out the circle shapes, it was way too big. For some reason the parametrics was not working in out favour. So after measuring the triangles and deciding on the most suitable size, we used parametrics to size it right. After a few tries, it was finally a success. Although some pieces were very loose and some were too tight when slotted with other parts, I still think this activity was a success. From the start to end where we had to design, make it in Fusion 360 and laser cutting it out, we did everything by ourselves. This made me really happy and proud even though the outcome was not perfect. From this activiy, I also saw the effects of kerf first hand as some of our slots were too loose after cutting even though the sized were made to be the same.

Overall this was a very fresh experience with the laser cutter, I really enjoyed my time trying to figure out the different sizes and details of the laser cutter. It was a tiring yet fruitful session with lots of knowledge gained. With this practical, I am sure that if needed in the future, I can operate the laser cutter to cut out the pieces we need in future projects.

Resources:

1. esp.sp.edu.sg. (n.d.). Error – Blackboard Learn. [online] Available at: <https://esp.sp.edu.sg/webapps/blackboard/execute/content/file?cmd=view&content_id=_1969071_1&course_id=_51831_1> [Accessed 30 Oct. 2021].

‌2. SendCutSend. (2019). What Is Kerf in Laser Cutting? [online] Available at: <https://sendcutsend.com/what-is-kerf-in-laser-cutting/> [Accessed 30 Oct. 2021].