Fab academy 2023 About me Projects Assignments Home

Project development

What tasks have been completed?

What tasks remain?

What's working?

What's not?

What questions need to be resolved?

What will happen when?

Work Status remarks
Concept Design Completed -----
Pathway and guide testing completed need some more testing
3D printed Gears and tested gears completed -----
3D printed Reservoir completed need more clearance
Base Milling Completed ------
Laser Cutting The Pathways Completed Have some issues have to fix in guide design
3D printing Guides Completed Need to try different Designs
Assembling the Gear Systems Completed Need to calculate the speed of motor
Electronics Design Completed -------
Electronics Manufacture Completed Testing completed
Programming Ongoing Need to test 2 motors in unison
guides full assembly Ongoing need to acquire screws and nuts
Top Part Machining ongoing need to complete the design of flexible gears
Flexible gears not started thinking of3d printing with TPU for time management
Final Assembly started Need to fix the issues with some parts

What have I learned?

Throughout the academy, I have been learning a lot of processes. I have learned what I was lacking and what I need to do. I can now visualize mechanical and machine parts and design them accordingly. However, I have less knowledge in programming and electronics. Although I have gained some understanding, I am still working on further improving my skills in those areas.

Design

The idea was to create a machine that works as a braiding machine and also as a skeletal braiding machine. Jogin came up with the idea to create a braiding machine that makes both work possible. The idea was to create a braiding machine with a reservoir to store the bobbins. In theory, it can create skeletal structures by changing the braid into the reservoir of the machine. So, when it comes to joints, the machine will distinguish the different links and create branches by using the braids in the reservoir.

So, with that in mind, I started my design. I have already completed designing the guides, paths, and bobbins of the braiding machine for the previous machine. Now, I need to make it fully into a braiding machine. To do that, I need to make the necessary requirements for the braiding machine, including a top part to pull the thread (the top thread pulling part assembly) and also my experiment, the reservoir.

The funny thing is that the reservoir always works in pairs in order to accommodate the opposing threads. The said design is important. If there is only one reservoir, only threads going in one direction can be collected. Well, it is not functional and not good, but for the experiment of that reservoir, it is necessary. The design is such that it will do the normal braiding process and it will also be in my experiment.

I worked based on my previous design and modified them a little bit. The things I added were a reservoir, which can hold the bobbins and can rotate using a separate stepper motor. While designing the reservoir, one thing I wanted to look into was the size of the reservoir diameter. The diameter of the reservoir should be larger than the diameter of the paths, and also the diameter of the reservoir should not be larger because it will consume more of the path. So, it was carefully calculated to find the sweet spot.

Because of the introduction of the reservoir, there is a break in the flow of guides. Naturally, the bobbins have a tendency to go in and not go into the reservoir. Even if we rotate the reservoir, the tendency still remains. So, in order to have better control of the mechanism, a servo-actuated guiding system is introduced. In the normal position, the guides will not permit the bobbins into the reservoir, and in the actuated condition, the servo will open a path to the reservoir and guide the bobbin into the reservoir, and vice versa.

The other thing in the design was the top part. The top part is supposed to have a pulling mechanism to pull the threads out of the design. I designed it with silicone in mind to make a casted piece out of it so that I can cast the flexible gears. The reason for choosing flexible gears was because the thread should be pulled and it should not clog in the gears. In the case of a sturdy object, it should not break. I used a linear rod and a stepper motor in that part of the design because I wanted to have better control over the speed ratios of the main motor and the pulling motor.

Electronics

The electronics consist of 3 stepper motors, 2 servo motors, a limit switch, and I wanted to connect a serial monitor to the computer because I had no purpose in having WiFi connectivity. Also, it had 2 limit switches, and it does not require any interrupt pins. With that in mind, I chose the SAMD11D microchip, which was ideal for my use.

The reason for choosing the chip was because of my familiarity with it, and it had an adequate number of pins for my use. With that in mind, I began designing in Fusion 360. Since I had 3 stepper motors, it was sufficient to have a 12V supply to the machine. I added a 12V input pin and SMD-type 12V connectors. For reverse current protection, I added it to the micro USB pin. After completing all of that, I showed it to my instructors and was ready to mill.

The design and milling process were fairly easy and went on without any issues. I tested all the programs and circuits for my board, and everything was working fine. I completed the circuit and was ready to program the board.

Manufacturing

Prior to manufacturing, what I did was create a small replica and tested the mechanisms of the braiding machine. By testing the mechanism, I was able to understand and fix any issues and preliminary errors. The mechanisms were working fine without any issues, which gave me some confidence in large-scale manufacturing.

My design consisted of laser cutting wood, milling, 3D printing, small casting, and a small metal milling. Most of the mechanical parts were 3D printed. However, the 3D printed gears had some clearance issues, so I added a 0.2 mm clearance for a loose fit of the gears. The bobbin parts were also 3D printed, but they had too much play and were easy to pop out if a pulling force was applied. To address this, I added a notch at the bottom of the design to provide a better fit.

The base and structural parts of the machine were made of wood. I used the Zund universal cutter in the lab because of its speed and automatic tool changer (ATC) feature. The ATC made it easy to change tools, and the machine provided a better finish compared to the shopbot. So, I used the Zund to mill the wood, and it was a fairly easy process.

The pathway for the guides was manufactured using a laser cutting machine. Laser cutting made the job easy and provided good results. I was able to cut the acrylic for the desired pattern within an hour, and after that, I was ready to assemble the machine.

First, I assembled the gear supports, which were 3D printed, onto the base. Then, I fixed the bearings in the gears and secured all 12 gears to the base. After that, I ran the program for the stepper motor on the board, and it was working in harmony with the gears. Next, I assembled the top guide and screwed the individual parts. Once the parts were fixed, I installed the reservoir and the supporting gears.

The tasks that are left for me are final assembly and bug fixing the programme