The Process
This week, we were tasking with practicing with metal cutting and post-processing. Using a diamond template, I wanted to create a bottle opener for my boyfriend. As a Kiwi, ex-golden gopher, and beer enthusiast, I wanted to include all of these elements in my design. Using Adobe Illustrator (AI), I imported the provided diamond shape, and created cut outs of the University of Minnesota “M”, New Zealand outline, and a middle cutout to function as a bottle top opener. Below is my resulting design.
After finalizing my design, I exported my design as a .dxf file, as the Torchmate program connected to the plasma cutter requires this file type. We imported my file into the desktop, ensured the scale was correct, and did a “dry run” before cutting. Luckily, in doing this, we were able to catch that I had not set the origin after jogging the machine to my desired location on the metal sheet. I set the origin, reset the machine, and watched the plasma cutter produce my two diamonds.
IMG_2162 (Video)
I retrieved my two pieces from the water, and patted it dry with paper towels.
For the post-processing portion, I removed the dross/slag with an angle grinder.
I followed this step with using files of various sizes to remove the remaining dross/slag, especially around the sharp, intricate angles of the cutout regions.
Next, I used the sandblaster to smooth out the rest of the piece.
Now that my diamond bottle openers were free of sharp and rough edges, I began planning out my painting process. I selected a turquoise color to powder coat my piece. After setting up, I applied an even powder coat to both diamonds before transferring to the powder coat oven to cook for 20 minutes at 400 degrees F. Turns out, I actually selected a clear-ish glaze powder coat, which would have turned out better if my post-processing was cleaner underneath.
I pivoted and decided to spray paint my pieces instead. I placed the diamonds on a piece of scrap cardboard and used a lime green spray paint to paint the pieces. After the sides dried, I used red paint to add a splatter effect to the pieces. After 20 minutes, I returned to find them already dry, and I was very happy with how they turned out! I think my partner will like them. 🙂
Before leaving, I made sure my workspace was clean.
Reflection
This was my first time using the plasma cutter, and I would like to explicitly say, thank you to whoever created the “How To Use” sheets. I had to come in and use the machine with Karl’s supervision, and during my first dry run, I realized my scale was WAY off. I manually adjusted the dimensions of the diamonds, and to my realization after the fact, they were still bigger than most of my peers’. There are a couple of other things I learned that I will try to remember for next time, including…
- Adjust speed of the plasma cutter for intact finer details and less dross. With leaving the settings as they were, my pieces had way more dross on them compared to my peers’.
- Be wary of some of the powder coat options. They do not always turn out the same as they did when first applied.
- When moving to the powder coat oven, it is necessary to pre-heat the oven. In doing this, however, everything, of course, gets hot. Use tongs, a heat-protectant glove to pull out the oven rack, and lower in the piece hanging from the paperclip from the top through the rack bars.
Cost Estimate
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | Aluminum sheet (12″ x 24″)
Powder coating powder
Spray paint |
$14.63 /board
$14.56 /can
$5.98 /can |
Home Depot
|
1 Board
1 Can
1 Can |
$14.63
$14.56
$5.98 |
| Labor | Plasma Cutting Operator and Post-Processing Engineer(me) | $20 /hr | Zip Recruiter | 3 Hour | $60.00 |
| Prototyping Engineer | $36 /hr | ZipRecruiter | 1 Hour | $36.00 | |
| Overhead | Plasma Cutter Access | $100 /session | TXRX Labs Workshop | 1 Hour | $100.00 |
| Total | $231.17 |
As I gain experience, the quality will increase, and production costs will drop as the time required to make it shortens. I spent some amount of time familiarizing myself with the machines used in this process, and that time will decrease with experience.
