I previously had novice experience in laser cutting as I went to a laser cutting workshop at Moody Makerspace at Rice. It is a shame to call myself a mechanical engineer without experience using a laser cutter and 3D printer. In this laser-cutting assignment, I get the chance to explore functions in Adobe Illustrator and work with vector files to achieve my desired laser-cutting piece.
I made a cute tiny wood key name tag with the laser cutter at Moody Makerspace earlier this semester.
Training before laser cutting my box
Shout out to Madison, the TA in the prototyping class, for walking through the steps in laser cutting in the training. I came in the next evening on the weekend when I had my nameplate design ready to test my ability to run the laser cutter independently.
I had to change the font in Adobe Illustrator because I couldn’t find the same font I chose when I was designing on my Mac.
It took me four trials to get the desired end result of my nameplate that will be used on the crate I built with Allen. I was struggling with (1) engraving without a vector cutting afterward, (2) not cutting through the wood, and (3) having the starting point too close to the edge of the wood.
I finally got the design of my nameplate out after four trials. It is a rewarding experience to gain confidence in using the laser cutter alone.
How my cute lil box was born
1. Measure the kerf (first and foremost)
This is the most important part of getting a press-fit finger joint box. Without a correct kerf, we cannot achieve the goal of making a snug wood box without the use of glue. I used the file KerfBox.ai from the Canvas File folder.
Laser cut the kerf box to measure the kerf for the box design to achieve a snug press-fit.
I got the average kerf size measurement of 0.015 in by pushing the 9 rectangle cuts to one side of the outer frame and dividing the gap measurement of 0.15 in by 10.
The gap measurement is 0.15 in for 10 laser cuts.
2. Design 2d drawing on laser cut box
I used a 2D drawing generated by en.makercase.com. On the website, the design parameters of size, material thickness, types of edge joints, and, most importantly, the average kerf size we measured in the previous step can be entered to get the box SVG vector file. I chose to make the box in the dimensions of 4 in x 4 in x 4 in to ensure I fulfill the requirements of at least 4 in. After getting the box vector file, I then went into Adobe Illustrator to have the college crest and personal information text on two sides of the box. Additionally, I wanted to have a photo engraving of my two kittens on two sides of my box.
My 2D drawing for the laser-cut box
3. Laser engrave and vector cut the box
As shown in the previous step to designing my 2D drawing in Adobe Illustrator, I wanted to have two photo-engravings of my two kittens. It turned out to be harder and way more complicated than I thought. I even went into online resources related to laser engraving photos.
This is the expected photo engraving result I was looking for after seeing this on one side of the laser cutting room.
I followed the instructions to convert my photo into grayscale and bitmap. However, I was nothing close to the originally anticipated result. Below is a summary of the settings I used for laser engraving and laser vector cutting.
- Vector Cut
- Speed: 15%
- Power: 100%
- Frequency: 10%
- Engraving (Text)
- Speed: 100%
- Power: 50%
- DPI: 600
- Engraving Trials (Cat)
- Speed: 10, 20, 100%
- Power: 20, 30, 50%
- DPI: 300, 600, 1200
- Dithering: Standard, Jarvis, Stucki
It took me 4 trials tuning different parameters such as dpi, speed, power, and dithering methods and referencing online resources, but it was nothing close to a photo engraving.
4. The end result of my laser-cut box
Even though I was not able to deliver the original design of my joint fit box with photo engravings of my two kittens. I was still content with the learning process, starting from getting used to the laser cutter, measuring out the kerf (an important part of success), and delivering the end result fulfilling the requirements for this laser cut box assignment. I achieved a press fit that was tighter than I thought. Someone even suggested I hammer the heck out of it to get it fit. I did not go to the extreme spectrum of assembling my box. With a little bit of force, I had no problem putting all six pieces of laser-cut wood together and forming a joint-fit box.
My Rice Owl is the highlight of the laser engraving, even without successfully getting the photo engraving done. Engraving: Speed (10%), Power (30%), DPI (600)
One final takeaway from my laser-cut box was that I was super proud of the laser engraving of my Rice Owl. I love the darkness of the engraving in the part of my owl’s eye. It really is staring at everyone who passes by.
I still love my kitten, Whiski, laying on the laser-cut wood without the expected clear resolution from photo engraving. Engraving: Speed (100%), Power (50%), DPI (600)
5. Clean up the workspace
Clean up everything after completing the laser cutting process and make sure people after me can have a pleasant journey in making their box
Reflection after completion
First, I would say getting used to both the Epilog M2 and Epilog Pro is important in understanding the basics of laser cutting. However, the placement issue of starting too close to the edge of the laser-cutting material can be solved and avoided by using the Epilog Pro. The camera system on the Epilog Pro can assist us in placing the preview of the laser cut pattern on the material. It is a more intuitive way of visualizing the design on the laser-cut material before actually starting the cut. The mock run on the Epilog Pro with the laser pointer on can further validate the placement of our proposed laser cut. I highly recommend the use of Epilog Pro if it is available.
Second, I would like to keep trying out photo engraving in my leisure time. It will definitely be a rewarding experience if I can successfully photo-engrave using the laser cutter.
Last, in future iterations of laser-cutting, I would like to try more complicated geometry of the box and put my laser-cutting skill into trial.
Manufacturing cost analysis
The overall cost of manufacturing the laser-cut box is $ 487.24 considering all materials, labor, overhead, and design. With the gained proficiency in using the laser cutter, the cost of labor and facility in using the laser cutter may be reduced to around 30 minutes which was the estimated laser engraving and cutting time for the entire box. The cost of making the laser-cut box can be greatly reduced by cutting the facility machine time to 30 minutes, as it is the limiting factor for the rather expensive manufacturing cost of $ 120/hr. With the labor and facility time cut to 30 minutes, I can achieve a reduction in the total cost of $ 350, resulting in an updated total cost of $ 137.24.
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | 1/4″ Baltic Birch Plywood 12″x20″ | $ 5.99 | woodworkerssource.com | 1 piece | $ 5.99 |
| Labor | Laser Cutting Operator | $ 20/hr | ZipRecruiter.com | 3 hr | $ 60 |
| Prototyping Engineer (You!) | $ 25/hr | Indeed.com (Engineering Intern) | 1 hr | $ 25 | |
| Overhead | Facility Cost (Machine Time) | $ 120/hr | lasercuttingshapes.com (Laser Cutting Cost) | 3 hr | $ 360 |
| Quality Control | $ 22.5/hr | Glassdoor.com (Quality Assurance Inspector) | 0.5 hr | $ 11.25 | |
| Design | Engineering and Development | $ 25/hr | Indeed.com (Engineering Intern) | 1 hr | $ 25 |
Total Cost: $ 487.24
