11. Mechanical/Mechine Design¶
Assignment: Mechanical Design (part 1 of 2)¶
Group assignment:¶
- Design a machine that includes mechanism + actuation + automation + application
- Build the mechanical parts and operate it manually
- Document the group project
Individual assignment:¶
- Document your individual contribution
Assignment: Machine Design (part 2 of 2)¶
Group assignment:¶
- Actuate and automate your machine
- Document the group project
Individual assignment:¶
- Document your individual contribution
Machine Concept: Introduction¶
We started the week with a few ideas for our machine, but we eventually settled on a machine specifically made to autonomously modify wires called the Cable Crafter. This includes cutting and stripping. A basic diagram we drew is shown below.
Essentially, the process begins with a wire on a spool, which is located at the beginning of our machine’s wire channel. It is pushed forwards on the machine by a series of double wheels located on either side of the channel the wire travels on. Once it reaches a certain position, a tool will strip the front of it before having a soldering iron tin it. Once the wire has traveled far enough past that position, the wire will be cut, stripped, and tinned, again, separating it into two. This process will be repeated for as long as the user wants, creating many individual wires. The second whiteboard in the above images represents the wire mechanism that will use the motor to push the wire from the spool into the channel.
Group Member Contributions¶
After coming up with this concept, I and my group members, Collin and Landon, began to decide who would do what when creating our machine. After some deliberation, we settled on the following roles:
Collin - CADing (creating a 3d model of our machine), programming, soldering/wiring components Landon - Programming and wiring most of the electronics (ex. coding the servo/potentiometer) Ryan - CADing (specific 3D printed parts), 3D printing, machine assembly (including soldering heat set inserts)
What I Designed (in Onshape)¶
Most of my contribution this week had to do with CADding our components. The first things I designed using CAD in Onshape this week were the wheels and gears our machine would use to push wires along the v-channel. To do this, I first had to figure out how large to make the wheels. Luckily, the actual size didn’t matter too much as long as a few criteria were fulfilled:
- The two wheels would leave a gap between them just large enough for the wire to fit
- The gears should be slightly larger than the wheels so tha they can spin each other
After considering these criteria and the size of our machine, I decided to make the wheels with diameters of 1 inch and heights of 0.25 inches. After consulting Collin about how to attach these wheels onto the actual machine, we also created shafts for the wheels to fit into as well as a hole at the top for the wheel to screw into. The picture below shows what the finished design for this wheel/gear piece looked like.
After creating this piece (and a few others which Collin made), we began to 3d print them out. One of the pieces that I 3d printed were these corner pieces designed to hold our machine together.
Heat Set Inserts: Corner Piece¶
I 3d printed 8 of these pieces over the weekend and brought them into the lab the next week to begin assembling our machine, as Landon was laser cutting out a wooden frame for our machine at this time. At the same time, I began to put heat set inserts into the holes of the 3d printed corner pieces so that we could actually connect them to the wooden frame. I did this by using a soldering iron set to a temperature of 300 degrees with a tip for heat set inserting. All in all, because each corner piece required 6 inserts, I ended up using 48 heat set inserts for this step (which took about 1-2 hours).
OLED and Potentiometer Case¶
Another piece that I designed/3d printed was the case for our machine’s OLED screen and potentiometer. Although I was originally going to design this case as something very simple, I ended up adding a few holes/tunnels through the case (connecting the electronics to the outside) to allow for better wiring.
To create accurately sized extrusions in the case for the electronics to fit in, I used calipers to measure the size of the OLED screen and potentiometer. Then, I created extrusions in the case which left roughly 0.1 inches of room for them to move around in case the case wasn’t large enough. The picture below shows what the 3d model of the case looked like.
Linear Slide/Actuator¶
I also made a 3d model of the linear slide/actuator that we would use to move the wire stripper when cutting wires. This was because we needed to know the dimensions of the linear slide (including the distance between each of its screw holes) to cad appropriate pieces for it. So, to measure the dimensions correctly, I used calipers. Then, I extruded a rectangular prism in CAD that was the same length as the linear slide. Finally, I created an offset sketch above that with the holes aligned with the actual linear slide. I extruded this piece as well. Later on, using this reference linear slide piece, Collin added a few aditional pieces onto what I made. The final 3d model is shown below.
Finally, the last piece that I will talk about here is the cover for our machine’s v-channel (where the wires are moved). When theorizing how to make our machine worked, we were afraid that the wires may bend while moving and therefore may not fit in between the wire cutter when they were supposed to. To fix this issue, I created a cover which was supposed to be taped on top of the v-channel. I did this using a revolve function in onshape, leaving a small gap (with a height of a few tenths of an inch) at the bottom of the v-channel for the wire to fit. A picture of the piece is shown below.
My Contributions: Documenting/Slideshow¶
While my group members worked on programming the motors/servos, I worked on helping keep us up to date on documentation and also worked on a small slideshow/presentation for our machine. This slideshow was planned to be used on our website for when we presented in front of Neil. A picture is displayed below.
I also worked on documentation during this time (mostly the machine concept, CAD, and assembly portions) and helped to keep us on track and organized.
Group Assignment¶
You can find more information on our iteration, CAD, programming, and assembly processes on our group documentation, found here.
Reflection¶
Overall, I feel decent about our progress on our machine this week. Even though it isn’t completely finished, I think that the experience I got with CAD, heat set inserts, and assembling the machine will be very helpful to me in the future, especially while working on my final project. My files for this week can be found here