4. Computer controlled cutting¶
Introduction
This week I worked on designing and fabricating various products using our lab’s vinyl cutters and laser cutters to practice my abilities with computer controlled cutting. I have taken all of the engineering courses that I have been offered by Latin thus far, so I had a significant amount of experience with both vinyl cutting and laser cutting prior to this week’s exploration of computer controlled cutting; however, as one of my primary reasons for taking this course is to take a deeper look into the possibilities of the many machines in our lab, I was eager to begin this week’s work. The assignment for this week was to design and cut a vinyl sticker and to parametrically design a modular tabbed structure that can be assembled into a larger structure.
Assignment
- Design and cut a sticker using the vinyl cutter
- Parametrically design a modular construction kit and cut it on the laser cutter.
Vinyl Cutting
As I mentioned previously, I have lots of experience using the school’s vinyl cutters, spanning all the way back to my first engineering course in the 7th grade. However, I had never experimented in-depth with more complicated designs such as multicolored and multi-layered stickers. After briefly refreshing myself on the relatively basic workflow of our Silhouette vinyl cutters, I knew precisely what I wanted to create. To commemorate my unflagging dedication to anything open source, I chose to create an accurately-colored FreeCAD logo with a matte black background that would be placed beside my peer’s and former Latin Fab graduate’s stickers on a window in our lab. The process of designing, cutting, and sticking my sticker is outlined below.
Designing the sticker
After deciding that I wanted to cut the FreeCAD logo, I imported a PNG of the logo that I found online and used the ‘trace outline’ feature in Silhouette Studio to define the path that I wanted the vinyl cutter to follow when creating my sticker. After completing the outline, I needed to ensure that the multilayered design would line up properly. To accomplish this I added a small square to the right corner of the design that I would line up when combining the different colored ‘F’ and gear to create the final sticker. I also created another file that was an offset of the trace that would become the matte background of my sticker.
Assembling the sticker
After cutting out the different colored portions of my sticker as well as the background, I was ready to assemble the sticker. After weeding the excess vinyl from each of the stickers, I lined up the different parts from each sticker using the squares that I cut on each part and stuck them together. Next, I collected the now fully assembled FreeCAD logo sticker and applied it to the matte background. As this was my first time creating a multilayered sticker, I was unaware of how well the vinyl would adhere to the matte vinyl which caused me to not achieve the perfect alignment of the stickers before applying the logo to the background. As a result, my sticker is slightly off-center on the background. Nevertheless, I am proud of my accomplishment and now know to spend more time on aligning the stickers prior to sticking layers together. I also encountered many air bubbles between the first and second layers. While I was able to reduce the amount significantly by deflating some of the bubbles by making small incisions in some of the larger bubbles, I was unable to eradicate all of the bubbles. To mitigate this in the future, I will plan the layering process in greater detail before applying layers. Ultimately, I feel that my sticker is of excellent quality for my first attempt at multi-layered design and it is now situated amongst the many other stickers that are located on a window in our lab.
Final Touches
Parametric Design
Designing my project
While I have designed and laser cut many 2D and 3D designs, I had never used parametric design prior to this week. Therefore, in beginning my exploration of parametric design I began with watching a short YouTube tutorial in which the creator displayed how to use parameters in Fusion 360 which is my preferred CAD platform. Following my completion of the tutorial, I decided to make a modular tower design that can be endlessly expanded to a certain extent.
For my parametric design project, I wanted to create a construction kit with a variety of parts to practice my 2D design capabilities and because I was told that I had to for this week's assignment, though I can assure you that it was mostly the former. I ended up deciding to create an interesting tower design that is supported by four of the same shape at the bottom which are slotted into a circle. I wanted the circle that I designed to have several spare tabs to allow endless expansion upwards through utilizing other pieces that connected to and were supported by the same circles as before. The end result was an interesting rocket shape that can still be further expanded should I decide to in the future. The process of creating my parameters and deploying them throughout my design was relatively simple after I got the hang of it in a couple of other designs.
Deciding what to create
For my parametric design project, I wanted to create a construction kit with a variety of parts to practice my 2D design capabilities in Fusion 360. I ended up deciding to create an interesting tower design that is supported by four of the same shape at the bottom which are slotted into a circle. I wanted the circle that I designed to have several spare tabs to allow endless expansion upwards through utilizing other pieces that connected to and were supported by the same circles as before. The end result was an interesting rocket-like shape that can still be further expanded should I decide to in the future. I’ve outlined the process of creating my rocket from designing the various components in Fusion 360, cutting it on one of our lab’s laser cutters, and assembling the kit below.
.
Defining my parameters
I began designing my kit by creating various parameters that I would use throughout the process of designing my kit. By using parameters, I would be able to change the dimensions of my entire kit proportionately by simply editing my parameters rather than editing the dimensions of each individual line in my project. I decided that I wanted to create my kit out of three different tabbed components that would slot into each other without an adhesive agent. I created parameters for each dimension of the unique shapes as well as parameters for the length and width of the tabs on the shapes, which would be uniform across all three, and a parameter for the final extrusion which was set to the thickness of the cardboard that I would be using to cut my design out of. My parameters included dimensions for my rectangle, triangle, and circle component.
Designing my project in 2D
After defining my parameters, I used them to create several shapes with tabs. To make the tab generation process faster, I utilized the “circle pattern” and “rectangle pattern” tools in Fusion 360 to duplicate tabs on all of my shapes and to ensure that all measurements remained uniform throughout the entire design. Using parameters made this process vastly more efficient, as I did not have to input a measurement into multiple different fields but instead could simply repeatedly type the name of my parameter. Finally, I modified my triangle to an interesting quadrangle to improve stability and added a slight angle to my rectangle pieces to add a bit more contour to my design. With the addition of this originally solely aesthetic feature I unwittingly made my design work flawlessly after cutting it. I will provide more details as to how this angled piece actually saved me from having to re-design my project when I detail the assembly process later on.
Extruding my design into 3D
After completing my design in 2D, I decided to extrude the design into 3D by the thickness of the cardboard that I would be using. I had already created an “extrude” parameter earlier, so I simply selected each one of my shapes and extruded them all by the “extrude” parameter, which was 0.125” for the 1/8th” cardboard that I would be using.
Testing my tabs
Though I have designed tabbed boxes many times in various 2D softwares throughout my time at Latin, I decided to use the “assemble” feature to verify that my tabs actually fit together. In hindsight, this was probably unnecessary as I had used the same “tab” parameters for each part of the kit, but I wanted to ensure that my measurements were uniform because this was my first time utilizing parameters in a design and I do not enjoy wasting material on problems that can easily be corrected. The assembly tool confirmed that my pieces did fit together despite them not being oriented correctly, but I figured that it would not be worth my time to flip them as all I needed to confirm was that the tabs actually worked.
Exporting 2D .dxf files from Fusion
After verifying that my tabs would work and slot together as I planned, I exported my file from Fusion 360 as a .dxf file so I could import it into Corel Draw to then send to one of our cutters. I had to use Corel Draw because Epilog, the manufacturer of our cutters, advises that all cuts be sent to the cutters using Corel Draw. Had this stipulation not been imposed upon me, I likely could have directly uploaded to a cutter's proprietary software using my .dxf file, but I am not interested in breaking a laser cutter so I had to go through Corel Draw.
Importing my file into Corel Draw
After exporting my file from Fusion 360 as a .dxf, I imported the file into Corel Draw and sent it one of our laser cutters. Using the optimized settings for ⅛” cardboard that my peers and I found whilst characterizing our cutter in this week’s group project, I sent the file over and prepared to start the cut.
Cutting my design
After preparing the settings for the laser cutter and sending the file to the cutter, I began the cut which lasted roughly two minutes. For my parametric construction kit, I used our lab's Epilog Fusion Pro cutter. As the Epilog software comes pre-loaded with presets for different materials, including a profile for the 1/8" cardboard that I used for my design kit, I simply selected the correct preset within the Epilog software and exported the file to the cutter. After exporting my file to the cutter, I simply needed to press the large 'start' button on the cutter and monitor the cutting process. When cutting my design, I followed the following workflow that was written by current Fab student Teddy Warner and Fab Academy alumni Kai Vincent.
Assembling my construction kit
Following the completion of the cut on the cutter, I removed it from the laser cutter and prepared to assemble my construction kit. Assembly was a relatively easy process due to the slight deviations in tab width that I created which allowed the tabs to slot together smoothly free of obstruction from the adjacent tabs that were being connected. I originally only cut one level of supports, but ultimately decided to cut another four rectangular supports and four more circular discs to add extra height and detail to my design and prove that my construction kit truly is expandable. This is the part where the slight angle that I left on my rectangular pieces saved me. Had I not included the slight angle the pieces would have touched the lower circles, preventing me from successfully attaching the four rectangular supports. However, the angle ended up allowing me to slot the rectangular pieces into the upper circle and begin to expand my tower. Final images of the assembled design are included below.
Construction Kit Conclusion
My first experience with parametric design was certainly positive, as it was relatively easy to learn and proved immensely useful in managing to get my design to satisfy the dimensions that I wanted it to as I was able to increase the dimensions of each line on my project proportionately by simply changing the values of a couple of my parameters. I will definitely continue to use parametric design in the future, as I oftentimes find it hard to visualize what my projects will look like when they come off the cutter, so parametric design provides immense latitude to change my dimensions with impressive celerity.
┍━━━━━━━ Group Project ━━━━━━━┑
Laser Cutting Group Project
After completing my personal work for this week, my peers and I worked on characterizing our laser cutter’s settings for two different materials, 0.125” cardboard and 0.125” plywood. We began by creating a .cdr file in CorelDraw and exporting it to our large Epilog cutter. Within the Epilog software, we began to change the values for different functions one at a time in order to determine the most optimal setting for each process. Our findings are compiled in extensive detail on our group project, which all of my peers and I contributed to writing. I have also included a brief description of what I did to contribute to our group project below this text.
My Group Project contributions
During this week’s group project I worked on characterizing the settings for our large Epilog cutter with fellow classmate Drew Griggs. We began by creating a color-mapped file in Corel Draw and exporting it to our laser cutter. We incremented the settings for each individual setting during different cuts to determine the most optimal setting for each value to allow our cuts to cut through the material but to also maximize the speed and electrical efficiency of each cut that we ran. After completing our tests to determine the best settings for the cutter, I wrote several paragraphs of the description for this week’s work on our site.