PRAC 1

 HELLO!! Welcome back to my blog👋!! This week we had a lab practical💻 based on laser cutting. In Singapore Polytechnic, we use a Carbon Dioxide laser cutter which is available at our Fabrication lab💡. We were basically tasked to cut out a parametric construction kit. We used the technique of slotting or press-fit to slot different shapes together to make forms of things.

 

Introduction

This laser cutter is able to cut wood, acrylics, cardboards and papers. This machine is actually able to cut and engrave on the materials. Cutting will occur when certain settings are set based on which material is being used. There are also some safety hazards📛 that we took note, such as:

• Do not stare into the beam while cutting is occurring.

• Do not use materials that contains chlorine(e.g.PVC) or Foam.

• Do not cut or engrave metal materials.

• Never leave a 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 material cannot be cut through, stop and check or focus lens might be dirty, continued use of dirty lens will result in cracked lens.  

We also need to save our designs as vector or raster files to be sent to the coreldraw software before the procedure of cutting continues.

Vector 

• Scalable resolution

• Small file in terms of size

• File format: EPS, SVG, AI

• Graphics consist of anchored dots and connected by lines and curves.

Raster

• Pixel resolution

• Large file in terms of size

• File format: BMP, GIF, JPG, PNG, TIFF

• Pixels appear like little squares on graph paper when the image is zoomed in or enlarged.

• Images are created by digital cameras, by scanning images into a computer.

But in this practical my team actually used Fusion 360 software to create our designs and transferred it to the Coreldraw software.

HANDS-ON PRACTICAL✋

At first my team actually wanted to create a Christmas tree with the shapes of a hexagon and a triangle. But in class after the help of our supervisor, we found out a triangle would not be feasible as there will not be enough space for the other shape to be slotted several slots. Hence we made a decision to change to a circle instead. This also affected a change in our final product to be a bowl instead. Take a look at our final products.👇👇

When we arrived at the lab, we had a competency assessment. This was due to assess if we do know how to use the machine in a  proper manner. After learning how to use the machine we proceeded to laser cut our shapes.

We do have an improved SOP procedure📜 so do refer below to find out more!!

NAME OF ACTIVITY: LASER CUTTING🔖

Purpose	To obtain a bowl made by slotting different shapes which will be cut by a laser cutter.
Scope	Ensure safety and follow the instructions based on this procedure.
Responsibilities	LEADER: Kalyani -make sure the team is on the right track and does not side track to something else -supervise the team when in need of help. LASER CUTTER OPERATOR: Madelaine -operates the laser cutter properly. DESIGNER: Jolyn -designs the objects the team wants to cut using the laser cutter. TIMEKEEPER: Cui Han -keep track of the time and make sure the team does not go over the time limit given.
Definitions	NA
Safety	Do ensure that there is nothing hanging from your body (such as lanyard) due to it being tangle into the machine Students with long hair are make sure it is properly tied up When opening the cover of the laser cutting machine. Ensure it is open all the way and not partially. When closing the cover of the laser cutting machine, do NOT slam the cover. Once close, check if the safety interlock panel has 2 green LED lights up before proceeding. If both green LEDs did not light up, open the cover and close it again. When operating the laser cutting machine, do not lean your body into the machine and avoid inserting your head and hand into it. After cutting is done, wait for 1 minute before lifting the cover, due to the machine being hot and there will be gases present, hence this 1 minute is to give it some time to exhaust the gases. Ensure to wear thermal gloves when removing the product from the machine.
Materials	5mm Wood
Equipments	Air compressor Fume extractor Laser cutter Computer(coreldraw, epilogue)
Operating procedures	START-UP Switch on the PC at the workstation. Switch on the air compressor at the back of the laser cutting machine. Switch on the fume extractor. Switch on the laser cutter by turning the key from ‘I’ to ‘O’ and wait until initialization is done and the panel shows “CO2 Fusion”. Once the initialization is done, proceed to the workstation to operate Coreldraw. OPERATION Observe that the 2 green LEDs on the safety interlock panel light up. At the workstation, turn on the Coreldraw software and insert your drive. Export the drawing from Fusion360 to CorelDraw by converting it into DXF format. To export it, select ‘File’, then click ‘Export’, proceed to select the file you wish to export. Once your design is shown on the Coreldraw software, select your line colour, fill and line weight for your design.  Select the area you wish to cut, and click the bottom right icon, adjust the colour so that RED is 255, while GREEN & BLUE is 0. If you wish to engrave, adjust GREEN as 255 while RED & BLUE is 0. Once you have completed your design on the Coreldraw software, click on the file to then print your design using the laser cutting machine. After you have clicked the print icon, your design will then be transferred to another software called EPILOGUE drawboard. Import your selected material by loading into the material library. For our construction kit, we selected “Wood 5mm”. Notify the person-in-charge before printing the product.  Manually turn ON ‘Auto Focus’ by setting it to thickness. Ensure the process type is set to vector and is set to 18%/80%/20% . Name the design “Kaya 7” . Place the wood on the top left side of the laser cutter. Align it along the border of the metal mesh. Close the cover gently once your material has been properly laid. Using the software at the workstation, move your design to the desired position on your material. Check with the person-in-charge about the jog feature. Once the checks are done. Process to click on Print>(M2), check the file name and then click on GO/Play on the laser cutter screen to proceed to laser cut our product. If the laser does not cut through the wood after multiple attempts, check that the lens of the equipment is clean as it affects the quality of the cutting. After cutting the wood, do allow some time, about 30 seconds to a minute to allow the fume extractor to extract fumes from the cut wood before opening the cover. To check if the parts are properly cut, wiggle the pieces in the cutter before completely removing it from the cutter. SHUT DOWN Once you are done using the laser cutting machine, switch off the laser cutting machine by turning the key back from ‘O’ to ‘I’. Wait for the screen panel to go black and when you no longer hear a rumbling noise, the machine is completely off. Proceed to switch the fume extractor off followed by the air compressor. Finally ensure the cover of the laser cutting machine is open before leaving. Perform housekeeping by cleaning up the table as well as keeping the remaining wood at the specific workstation.

Reflection📝:

During our competency assessment, we learnt to tweak our design by using features on the Fusion360 software. We learnt how to use the parameter characteristics to make adjustments to the width of our slots by just changing one parameter, thickness. This made it so much more convenient and less time-consuming. Hence this made our kit fit much better.  

We then cut our first two test pieces, we cut one of each shape and test whether they fit each other, we aim to have the shapes to connect easily to each other while not being too tight to take it apart. Unfortunately, the slots were a bit too big and the shapes fell out easily due to it being too loose. Hence we then made adjustments by kerfing using Fusion360 and tried again. Take a look at our first try.👇👇

 After cutting out our shapes in our second try, we found out it was so much better than our first try. By slotting the 2 different shapes together , they fit much better than the first try. The shapes made fulfilled our requirements. Hence our second try was a success and we then proceeded to print multiple pieces of each shape. Take a look at our final shapes which were cut. we also took a video of the process ,so enjoyy✌👇

We met online as my team could not find the time to meet up in real life. Take a look at our bowl we madeee!!😬👇

After reviewing our first experience in laser cutting, we at first thought that we would be able to get the final product on the first try. However, at the lab, it took us multiple tries before getting the correct dimensions of our shapes. Before using a circle shape for our parametric design, we used the shape of a triangle. But then we later learn, the shape is not feasible due to the lack of spacing for the slots, hence we scrap the triangle design and replace it with a circle design. We also cut too many pieces for our parametric design and went over the limit. We did this so that we can have backups just in case we break any of the cut out shapes.