Semester 2- Week 6 Kierstin

 Worked on Deliverable 6:

“ include prototyping of each individual component, as well as the system integration prototyping. Evidences of your prototyping work (description of how each part was made, difficulties encountered, how you would improve for the future, and pictures) should be included/shown in your report.”

Started the tubing component and wrote out the outline for what other individual components and system integration components there were.

Each Individual Component: 

Tubing: 

• We are currently using tubing with a .3mm ID and .6mmOD 

This was ordered from a medical grade silicone company and is comparable to the silicone tubing used for the Ahmed Valve. 

• We also tested tubing bought off of amazon with a .3mm ID and a ____ OD. This tubing was much thicker than the medical-grade tubing, so we decided to stop using it. 

• Difficulties: 

• The tubing is quite small, so it is very difficult to work with. 

• It is hard to thin the walls, and it is also hard to insert needles, or resistances inside of the tubing because of the small ID. 

• Changes we have tried to make: 

• We have tried to thin the walls making an incision with the scalpel that doesn’t puncture the tube all the way through. 

• We have tried to heat and stretch the tubing to thin the walls. This resulted in the tube catching fire, or becoming frail with cracks. 

• We have scraped the tubing and shaved off silicone to thin the walls. This is currently our best method if we end up needing thinner walls. 

Valve Housing: 

Resistances: 

System Integration:

Tubing Inserted into Housing: 

Resistances Inserted into Tubing: 

Sealing Housing and Tubes: 

I put this in a shared document for our deliverable and wrote an outline for the team, and made a tentative plan for who would do what section.

Class: 

Lab work: 

Manufactured new small valves. This took a long time because of how precisely I inserted the tubing and had to cut the sides. I wanted to prevent any folding of the tubing, and I didn’t want to create any punctures while thinning the valve, while still making it fairly thin. I manufactured 4 valves (seen on top of the plastic bag with the other valves), but there were many valves that I had started to make, and then made some errors so those were thrown away. They can be seen in the second image above with all the scraps. 

Set up the lab for testing (calibrated pressure sensor, height, etc) and tested the sutures at different heights. 

We wanted the different thicknesses of sutures, so we redipped in the super glue. This is shown in the image where the sutures are labeled with how many coatings of glue there are. 

We reran the tests and our data was very skewed. We think this is because the coatings weren’t different thicknesses, and the suture was getting saturated with water. We needed to come up with a different method for coating the sutures so they would be waterproof, and slightly thicker. We also asked Alex to order some different-sized sutures of polyester and nylon. 

The multimeter also ran out of batteries, and the new one was giving slightly different values. So we had to work with it and try to figure it out. 

Sensor cases: 

Lab work to test valves and do system drip tests: 

Brinkley and I tested all the new valves that we made and labeled if they leaked and how well they functioned. These valves are the best ones we have made yet, and most of them worked really well, and only one leaked. One thing we noticed, was that the tubes don’t flow evenly unless they all connect at the exact same spot inside the housing. So that is something we will have to be aware of when manufacturing. 

We did all the testing with the valve that had the most even drip rate through all three tubes, and that didn’t leak.

We inserted the dipped sutures and tested them at different lengths. They weren’t giving data that we would have expected, so we realized there really was an issue with our superglue coating method. Then we coated the sutures with the hard epoxy shown in the images and hung the suture to let the epoxy harden and dry overnight. (Shown in the third and fourth pictures above)

Then we retested with the epoxied sutures (shown in the last picture) and got no drips because it was too thick. We then made the lengths of the sutures shorter (which is the recorded data) but still, we were not getting any flow even at high pressure. We will need to try it with a thinner suture and see how it works, and we will also test it with the sutures that Alex is buying.