Semester 2- Week 2 Kierstin

 

Lab with Brinkley, candle test: 

The photos above are of Brinkley and I measuring the tubing before and after trying to heat and stretch it over the candle. The silicone caught fire on the first attempt of stretching because it was too close to the flame. During the second attempt I held it higher and it stretched from 201mm-204mm. This was good, but it did not work as well as we were anticipating. I also attempted to make a thin incision on the wall of the tubing to weaken it without puncturing a hole. I accidentally punctured it on the first attempt, but not on the second, so we need Fady to test it to see if weakening one wall makes a significant difference. 

One other method that might be good to try, is to make a couple of incisions like the one above around it to weaken the tubing in a couple of sides without puncturing it. I think that is a test I will try next week if the shaving method does not work. 

I drew up this mold for us to make different-sized silicone valves. They are .35in deep and the heights are shown below. This will allow us to have a uniform shape, and also work on sizing down the valve. I will need to practice sealing the silicone tube into these molds and figure out a way to drill holes that will be the right size so they don't restrict the flow or the tubing within the valve.

The purpose of having different sizes is to work on scaling down the design and continue to make it closer to the size of the Ahmed valve. I will make a more accurate shape and size as we continue to manufacture.

I also drew up stands that we can stretch the tubing through for our candle test to get a uniform stretch. The base can be added or removed to bring the tubing closer or further from the candle heat. 

The idea behind the stands is shown in the drawing below. 

This will allow the silicone tubing to remain at a fixed height as the heat allows it to stretch as it is held taut. 

I had a lot of trouble sending in a printing form. It kept telling me there was an error, so I went into the printing lab to rescan the form. Turns out my google storage was just too full, so I used the CBU screentime account to send in the forms. It messed up the first submission because of the change of accounts, but I resubmitted them and got confirmation that they were received. It just took a bit of time to trouble shoot and figure out the issue.

Lab with Brinkley: 

The print lab did print the stands for the candle test, but we did not have a lighter so we just set up the test without actually doing it. We used that time instead to shave the edges of the tubing with a very sharp suture. We saw that some of the silicone was flaking off, so now we are waiting on Fady's test results to see how much shaving it and thinning the walls affects the expansion pressure. When we tested to see if we had punctured any holes, there was no leakage. 

The print lab for some reason did not print the molds for the valves, so I resubmitted. We will fill them with silicone and test Natalie’s spray once it is printed. We will also have to work on how to seal the soft silicone with the silicone tubing so there is no unintended leakage.