Week 1

June 17-21

This first week has mostly been me learning about the new meterials and getting familiar to everything we do in the lab. I watched video about basic fluid dynamics, learned the process of building a model and how to use the pump that I will be testing.

About model building

One of the main things we do in our lab is building models. There are three main steps in building a proper model for testing. The first step is using the computer to build a 3D model from the CT scan. The first picture is a CT scan of the vessel and by using this scan. we can build a 3D model of the vessel. The second step is printing the 3D model. We use PVA (polyvinyl alcohol), which is a soluble material to print the model. Some support came with the model, so it is necessary to remove the support from the course and polish the core. The last step is to build the silicone model. The 3D printed model is placed in a box filled with silicone, the silicone box is later put into water so the PVA core would resolve in water, leaving us with a completed silicone model.

What we did with Model this week

We worked on the seventh step this week. We first built a box with an acrylic board. We used hot glue to glue the board together. We had some trouble with it at first. It is really hard to keep the board on the right place and perpendicular to the one on the bottom, so we have to keep adjusting the boards to make them into a nicely shaped box. After we glued the box together with the core in it, we added silicone into the box. There are bubbles formed when we were mixing the silicone so we had to use the vacuum chamber to remove the bubbles in there. The silicone than gradually become solid in about two days, and after that, we are done with a final silicone model.

Acrylic box with the core in it

Sillicone with bubbles in the vacuum chamber

Putting the sillicone without bubbles into the acrylic box

Completely filled box with sillicone and core in it

About 3-D Printing

3D Printing or Additive Manufacturing is a huge part of the process of making a model that is validated for testing in our lab. There are two main types of 3D printing that we use in this lab and they use different techniques to print objects. The first one is Stereolithography which involves using light to harden gel to build layers. The second one is fused deposition modeling. Which is using heat to heat the material and add it onto the printed parts layer by layer.

This printer uses stereolithography technology. There's gel at the bottom of the printer, a laser is embedded under the gel. When printing, a mirror will reflect the laser to where the gel needs to harden, and a layer is thus built. This layer will be attached to the platform on the top of the printer and move up with the platform. An object is thus built layer by layer.

This printer uses the fused deposition modeling technique. The platform is at the bottom and there is an extruder on the top that would move in X-Y direction and form the 2D image. The platform will move up and down in the Z direction as layers are added to make the printed object 3D.

About Basic Fluid Dynamics

This is my notes about basic fluid dynamics. In here I explained the law of conservation of mass, Bernoulli's equation, viscosity, the venturi effect, etc. These are important in understand what we do in our lab.

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