3. Computer Controlled Cutting¶
Weekly Assignment:¶
Group assignment:
- Do your lab's safety training
- Characterize your lasercutter's focus, power, speed, rate, kerf, joint clearance and types
Individual assignment:
- Cut something on the vinyl cutter
- Design, lasercut, and document a parametric construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways,
- For extra credit, include elements that aren't flat
Vinyl Cutting¶
I was assigned to make a vinyl sticker, and the tradition in our Fab Lab is that Fab Academy students make one this week to go on a window. Mines was inspired by stained glass and the New Year, which reflected in its color scheme.
These are the colors I gathered to use.
I also almost made a mistake in using acrylic sheets as opposed to vinyl. Tyler Russell let me know that the vinyl has a paper backing, while the acrulic has none, as seen to the right above. They cannot be used interchangeably
2D Design¶
I found a reference that added a personal touch, of my zodiac sign, and it already had some of the red and yellows of the CNY color theme.
I imported my image into corel draw, tracing the bitmap with outline trace and detailed logo. However, my image had a watermark, and that affected the bitmap. It made it miscolored and blotchy. Using a watermark remover, it removed the watermark quite well.
Then, doing the bitmap trace again, the vector image was much much cleaner and there were no more inconsistencies. I used the right hand settings to adjust how I wanted my lines to look.
I also rescaled the size to 2.5 in as the width, making sure to lock the ratio before entering.
Next, I needed to export that file to Silhouette Studio Designer Edition. There was mixed advice on whether it should be exported as a .dxf (bottom left) or .svg (bottom right). Angleina Yang found .dxf to be more effective, but I could not figure out how to go forward through that method. Tyler Russell got his working using a .svg file and helped me figure out how to go forward with tracing it. I ended up going the .svg route.
I then traced my entire image by going to Trace, Select Trace Area, and Trace. I seperated the traced outline from all of the colors, which were not needed.
I saved it as a Silhouette file.
Vinyl Cutting¶
I opened the file onto the computer that was connected to the Cameo vinyl cutter. I went all the way to the rightmost tab "Print" to change some of the settings. The main change was to change the material to Glossy vinyl, which applied to the sheets I planned on using.
I placed the sheet with the backing still attacked onto the cutting mat, which is flexible and tacky enough to grasp the sheet. I aligned the upper left corner of the mat and clicked the ^ pointing arrow for the machine to secure it in.
I went forward with the print, but realized early on that it was awfully close to the top of the mat. I wasn't sure though and I couldn't get a clear enough view of the top to check if the print was placed where it should be. Once it finished and I took it off though, my suspicions were confirmed.
It had gone over by a little, so I had to adjust the design on Silhouette to be a bit lower. and not so close to the edge.
And then the print worked! I finished cutting the rest of my sheets.
But, when I sat down to begin weeding, I faced another printing issue. I had used a metallic sheet and the settings were not effective on it. It was really really hard to use tweezers to take off sections I wanted to remove and I even had to bring in an x-acto knife.
I did not want to waste my time doing every intricate detail with the knife, so I went to reprint it, this time using Metallic Vinyl as the material setting.
This time, the cut went deeper, as metallic vinyl sheets are usually thicker, and it was easier to peel off. With all the printing sorted out, I went forward with the weeding and assembling my sticker.
I really liked how it turned out, others seemed to realize the stained glass effect I was going for! I added it to the window as per the Charlotte Latin Fab Lab tradition.
Files for this section:
Group Assignment¶
For the group assignment, I worked with Tyler Russell and Angel Fang. Our directive was to characterize our lasercutter's focus, power, speed, frequency, kerf, and joint clearance. The documetation can be found here.
Joint Clearance Test¶
My contribution was on the joint clearance testing. For it, I made a comb cardboard shape that Neil Gershenfeld described when explaining what the test was on Wednesday. The comb is meant to have differing widths for the gaps to find the most suitable one for the cardboard at our lab.
Using calipers, I measured the cardboard to be 0.148 thick. I made the widths of the gaps change in increments of 0.025 in, so 1.43, 1.455, 1.48, 1.505, and 1.53. I designed the comb shape in CorelDRAW using the rectanglular shape tool and virtual segment delete to design the desired object.
I changed all of the lines to hairline and saved it as a CorelDRAW file (.cdr). After downloading and opening the file on the computer connected to the laser cutter, I went into preferences. For the vector settings, I went with 25s, 100p, and 15f.
I also needed to change the Job Type to vector, because I did not plan on doing any engraving. For the Piece Size, I changed it to 30in x 20in, aligning with the dimensions of the cardboard piece I was using (I should have changed my canvas size to the same for better placement). With all of those settings changed, I cut my design out.
(From left to right, thinnest to thickest)
After testing them all out, I realized that there was not much difference of a difference between how the cardboard fit into the gaps, especially for the ones that are wider than the cardboard thickness. So, I changed my design to be in increments of 0.05 in as opposed to 0.025, which I originally considered to be significant. I added number labels to it as well:
This time, I made sure to make my canvas size 30in x 20in.
I kept the same cutting settings, but for engraving I made power 40. The cut went well!
I found that the smaller values made it way too tight, to the point where pushing it through required a lot of force.
On the opposite end, the widest was really loose and unable to securely hold the carboard. The exact center was also a rather tight fit and a little bit wider was a little too loose.
I thought that right between 0.148 and 0.152 was the perfect fit, so 0.15!
This is the file for my final joint clearance printed design.
Parametric Design Kit¶
I took inspiration from Griffin Orsinger and Angelina Yang's parametric designs.
As I mentioned previously, 0.15 was the joint clearance I determined through my test. Angel and Tyler found the laser cutter kerf to be 0.015, so I added that into my width, making it 0.18.
Referencing Angelina's documentation, I worked on the XZ plane. I drew a 2.5 in diameter circle and created the tabs using rectangles with dimensions 0.18 in x 0.50 in. I used the circular pattern tool to add more around.
To create the tabs, I used the Trim tool to 'erase' the lines I did not want.
Chamfer did not work on points of non-straight edges, so I went with fillet and a radius of 0.05 in.
I applied all of these tools for my other designs, and they turned out just as planned.
I exported my design as a .dxf file. However, when I imported it into CorelDRAW, it showed up as a horizontal line. Angel helped me realize that it was because I had been working on the XZ plane and imported the .dxf file with the setting set to Top. Of course, if I opened it viewing it from the top, I would only see the flat angle of my design. The 3D Projection setting should have been front.
With that, it turned out perfectly.
Laser Cutting¶
I made copies of my designs and rearranged them to be sent to the laser cutter. When I opened it in the laser cutter's software though, I had to manually scale it back down.
I faced another issue trying to get the print to start. When I clicked Print, it would give me a loading icon, but fail to send it to the machine. When I tried selecting Send to JM, it worked and opened up a new window of the software. On the window, my new project registered.
When I checked on the machine's screen, I saw it as a listed job as well. I selected it on the machine and clicked the start button.
The cuts were going very cleanly and I was really satisfied. I knew the laser was going completely through because when it finishes a piece, I can see the piece sinking slightly, showing that it is fully seperate from the main carboard. One thing that I didn't quite account for (but did not impede the cut or final product) was how the carboard had a slight warp and bowed upwards. So I guess it kind of does fit the extra credit item of an element that isn't flat, but in a sardonic way.
And I was able to assemble the pieces into various shapes! They did not have a particular form, but it was fun to play around with the mix-and-matching.
Files for this section:
Files¶
Design Files:
Overview¶
This week was another week that was mostly review. It did, however, help me gain a better understanding of the laser cutters I use. Kerf, focus, and some other terms have turned up in my classes before, but I never personally measured them. Most of the settings I used in the past were ones set up for me that I simply copied into my settings for use.
My favorite part of this week has to be the vinyl cutting. As annoying as weeding was at times, it was incredibly satisfying and turned out the way I envisioned it. I definitely see myself doing some more personal vinyl cutting projects.