Laser cutting (Parametric Design Kit)

 This practical, we had to operate a CO2 laser cutter, for which, we had to be prepared on.

Before the practical

To make sure that we were competent, we had to go through the assessment and make a test piece.

After that, we worked as teams to make our pieces. We had to make a Standard Operating Procedure before the practical. However, during the practical, we found that the SOP had missing steps or steps that would be better suited for different order. As such, we had to improve our SOP.

During the Practical

Improved Standard Operating Procedure

Safety

·         Do not wear anything hanging from the neck

·         Tie up long hair

·         Open cover fully

·         Do not put head under the cover

·         Do not slam the cover

·         Check green lit LEDS to know if cover is fully closed

·         When cutting, do not lean over the cover

·         Do not cut metals, foam or chlorine containing materials

·         Do not stare into the beam while cutting

·         Check that the focus lens is clean

 

HAZARD IDENTIFICATION				EXISTING RISK CONTROL	RISK EVALUATION & CONTROLS
No.	Activity	Hazards	Risks	Existing Risk Control	Severity S	Likelihood L	Risk Level	Is the risk acceptable?	Additional control	Action Officer, Designation (Follow-Up Date)
1	Lifting fume hood after laser cutting	Chemical Fumes from the laser cutting machine may not be fully removed.	Chemical Inhalation of the fumes may cause internal body injuries	Administrative Control Train operators to wait 1 minute after laser cutting to allow fumes to be fully extracted before lifting the fume hood	Minor	Rare	Low	Yes	Supervise activity by the Technical Executives.
2	Observing laser cutting of material	Physical 1. Staring into the beam while laser cutting.	Physical 1. The laser beam is extremely bright, and it might cause eye injuries if stared at for too long.	Administrative Control Users will go through a demonstration and are tested in following the correct procedures when operating the laser cutter machine, which includes being taught not to stare at the beam and leaving the machine unattended.	Moderate	Rare	Low	Yes
3	Placing and retrieving cut material from the laser cutter.	Physical The surface of the laser cutter is a sharp net-like structure is made up of thin sheets of metal. The plywood may cause splinters.  Hitting the head against the printer cover. Printer cover may fall down.	Physical The thin sheets of metal and printer covering may cause bodily injury such as skin cuts and bruises. The cover, if not fully open, hitting the operator’s head or hand as they reach in..	Administrative Control 1.Operators carefully retrieve and place the material. 2.Operators are taught to fully open the covering.	Minor	Rare	Low	Yes	PPE Provide anti-cut gloves to laser printer operators for handling the materials.
4	Closing the printer cover	Physical Leaving hands or fingers inside the laser cutter as the printer cover is closed.	Physical Minor injury to the finger or hand may occur, if the cover is closed with force. The cover may break if closed forcefully, causing damage to the machine	Administrative Control 1.Operators are taught to close the covering gently.	Minor	Rare	Low	Yes	Supervision during operation.
5	Laser cutting of material	Thermal The laser cutter may cause the material to flare up and start a fire.	Thermal Flare ups in the material can occur and may lead to fires if flares ups are not contained early enough.	Administrative Control If a laser cutting machine is found to be left unattended, facilitators will turn off the machine. Users will go through a training and are tested in following the correct procedures when operating the laser cutter machine, which includes being taught not to stare at the beam and leaving the machine unattended. Fire extinguisher present.	Major	Rare	Medium	Yes	Supervision to be necessary during operation.

Start Up

1.       Turn on the air compressor (red switch)

2.       Turn on the fume extractor (green button)

3.       Turn on the main laser cutter (black switch)

4.       Wait for laser cutter to finish initialization

5.       Proceed to workstation for uploading of drawing/design

CorelDraw to Print

1.       Use vernier calipers to measure the thickness of the material

2.       Place cutting material into laser cutter

3.       Import DXF or SVG file

4.       Set line weight, color and fill depending on your needs [cutting, engraving or scoring] (Vector Cutting: Red, hairline, no fill) (Engrave: Green, no weight, Green fill) (Engrave Etch/Score: Green, hairline, no fill)

5.       Click print when ready

6.       Turn on Auto Focus (thickness)

7.       Select drawing and click import material settings and choose the material used for cutting

8.       Note: Under import material settings there are 2 tabs: Engrave and Vector. Use Engrave tab for engraving, Vector tab for cutting

9.       Type in the thickness of the cutting material measured in step 1

10.   Turn on air assist

11.   Click print

12.   On the laser cutting machine, verify the name of the file you are cutting and estimated cutting time and click the green button ‘GO’

13.   Place cutting material into laser cutter.

14.   Close fume hood fully. Ensure that the two LEDs at the side are lit up.

15.   Press the green button "GO/PLAY"

16.   After printing is complete, wait for 1 minute

17.   Open the cover fully and remove the cut design

Shutdown

1.       Remove any materials in the laser cutter

2.       Turn off the main laser cutter (black switch)

3.       Turn off fume extractor (green button)

4.       Turn off air compressor (red button)

5.       Perform housekeeping

Issues that came up

During the practical, we knew that we would have to account for kerf, so we started off with just 2 pieces to test if they would fit together. However, it tool us a very many tries to get the size right. Since our pieces have protrusions on top of slots, we had to make sure that they fit together. This took a lot of tries and, in the end, we made 5 sets of test pieces. It was discouraging, however, we persevered and kept trying again and again. The first three were too loose so by the fourth time, we decrease the measurements drastically. This made it so that pieces would not fit. The fifth time, we double checked the thickness of the wood for that particular area which helped and so by the sixth time, we finally made pieces that fit!

After practical reflection

I think that this practical was very fulfilling. Since we had to do the cutting so many times, when it finally fit, I felt even more proud of our final product and the persistence of my groupmates to get a parametric kit that actually worked. From this practical, I now know that accuracy is very important to make sure that the pieces can be put together and we always need to check the measurements to avoid the long detour my group made.