LASER CUTTING

 Reflection on Laser Cutting tutorial lesson:

For week 2's lesson, I was introduced to laser cutting, which is a technology used to cut and engrave materials. In SP, we use the carbon dioxide CO2 Laser Cutters in the Fabrication Lab. 

The main parts of a CO2 laser cutter are the exhaust also known as fume extractor and air compressor. The exhaust eliminates and removes hazardous gases and air contaminants such as unfiltered dust and small particles during the laser cutting and engraving processes. It is also used to filter the CO2 gas and discharge it to the surrounding. The air compressor on the other hand is used to help compress the air to provide the laser cutter with the gas(CO2). The cutting gas will then be directed to the cutting head where it will be in the form of a laser and proceeds with the cutting or engraving process.

I learned that when using Coreldraw, to vector cut the material, I have to use the red color whereas to engrave, green color is to be used.

One of the main terminology to take note of in laser cutting is the kerf. Kerf is the amount of material that is removed due to the laser's own width displacing some of the design cut out from a piece of material. This problem may cause any tabs or slots that are cut to come out slightly larger than we have dimensioned it to be. As a result, the fittings are loose when connected. Hence, to overcome this, it is advised to make the tab or slot 0.01" smaller than the actual dimension.

Some of the safety hazards to look out for during laser cutting are:

• Avoid staring into the beam while cutting 
• Do not use materials that contain Chlorine or foam
• Do not cut or engrave metals
• Never leave the machine unattended while cutting/engraving
• If a small fire occurs, attempt to extinguish it by blowing it or removing material from the laser cutter.
• If the material cannot be cut through, STOP & CHECK  to see if the focus lens is dirty.

Improvised Standard Operating Procedure for Laser Cutting

-The improvised parts of the SOP are indicated in green. I have added some details to make the steps more specific so that it is easier to navigate through the entire process. Overall, most of the steps that we prepared in our first SOP are correct.

·       Procedure

a. Start-up

S/N	Steps/Description	Action
1	Ensure the 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	Ensure the power switch for the pump compressor is turned on. Switch on the air compressor from the back located at the side of the machine.	Press ‘I’ or “II” on the red switch
6	Switch on fume extractor/exhaust from the back located behind the machine. Wait for 1 minute	Press the green button
7	Ensure the 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	Open Coreldraw app.	-
2	Open the file that is going to be cut out/ engraved.	Click file>import>select design
3	Adjust the size and position of the selected design on Coreldraw.	-
4	Identify parts to cut or engrave.   For cutting: Select the parts that are going to be cut out. Change the color to RED and the width to “Hairline”.Adjust colour settings for RED(R:255,G:0,B:0)   For engraving: Select the parts that are going to be engraved. Change the color to GREEN and fill the whole shape with green. Adjust colour settings for GREEN(R:0,G:255,B:0).To fill, click on the green color on the bottom left of the screen.	Open the “Outline Pen” tab by double-clicking at the bottom of the screen to change color and width
5	Send the file to the 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 on top.	-
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 engraving: 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 caliper. 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 the button beside “Air Assist” from OFF to ON
12	PRINT out the design	Click on the “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 the 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 the 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 the air compressor from the back located at the side of the machine.	Press ‘O’ on the red switch
6	Perform Housekeeping. Do not leave anything on the computer table.	-

 

Laser Cut Product from  Individual Competency Test:

Group laser cut product:

loose shapes

constructed product: A Christmas tree

                            

Reflection on Laser cutting experience:

Overall, this laser cutting practical was definitely a new and interesting experience. From the pre-preparation to the actual practical and finally the post practical; everything serves its purpose in enhancing this experience. For the individual competency test, I was able to pass my test on the first try as I was prepared well before the actual practice. The external guides provided by the lecturers and my own research from youtube definitely came in handy on that day. I was pretty satisfied with my laser-cut product as the sizing was alright.

As for the group product, we were able to laser cut our construction kit to form a Christmas tree. The parts that make up the tree were designed using parametric in Fusion 360. We constructed 2 different shapes which were the five-sided flower-like shape and a triangle. Then it was exported as a . DXF file and saved into a thumb drive so that we can use it in the computer in school connected with the laser cutter.

One of the problems we faced during the laser cutting process was that after the second shape (flower-like shape) was laser cut out, we realized that the sizes of the slots of both shapes were not identical, hence it was difficult to fit them together. We tried multiple times to get the right size, some were too tight while some were too loose to fit. It took us a while until we finally got it. This little problem was made easier to solve as previously we made our shapes with Parametrics on Fusion 360.

Looking back, we realized that this problem might be due to kerf. Even as we made the size of the slots to be identical to each other, they still could not fit. We should have accounted for kerf even before we started laser cutting our shapes out. This is the knowledge that our group can bring forward with us to our future projects that may need laser cutting. Another problem we faced was getting the right size for our flower-like shape. Some of the flower-like shapes were laser cut into a big size and some were smaller as shown from the photos below. We resolved this problem by adjusting the boundary size accordingly into CorelDraw by using the ruler. Nonetheless, we were really happy with our construction as the final product was achieved.