Name: Avinash Shivakumar

For this assignment, we were tasked with producing some object that cannot be produced feasibly through any means other than 3D printing. I had started brainstorming for this project while we were learning to IronCAD for the Computer Aided Design assignment (Homework #7), when I learned that Dr. Wettergreen expected this of the 3D printing assignment. While brainstorming at my dorm, one of my friends passed by, wondering what I was doing. Upon explanation, he immediately recommended that I take a look at a Klein bottle, explaining that, although it had once been thought to be an impossible object, modern techniques made it a feasible object to produce. I found the design intriguing, so I ended up settling on this for the assignment.

First, I needed to visually conceptualize the Klein bottle. At times, I felt that this was a little difficult to grasp but, overall, it was quite comprehensible. Basically, the Klein bottle is all composed of one surface. Its base is able to be set stably on a table but also contains a hole in its center. This hole translates to a pipe that travels up into the body and then out of the body at an angle along on of its sides. Once out of the body again, the pipe loops around to converge with the body at its apex in order to empty out into the cavity that comprises the rest of the body. In this way, in order to access the fluid in the body, it is necessary to traverse the top of the body through to its side to finally empty out in the base. In a practical setting, this would likely require the rotation of the structure along a horizontal axis. If the purpose were to fill the cavity with fluid, it might be preferable to design a large tube length for easier transportation of a larger amount of fluid. Due to the constraints of this assignment, however, (namely that the part must “fit within a 2x2x2 inch cube”) in order to keep the part at least somewhat aesthetically pleasing.

After this visualization step, I began designing the Klein bottle in SolidWorks. It took a lot of trial and error to figure out a way to design the structure that worked, and then to get that structure fully functionally proper. At first what I had thought to do was to create the entire structure as a solid object and then hollow it out, while punching a hole in a side for the pipe to pass through. Logistically, I was not able to find an easy way to do this in SolidWorks. To put it briefly, I eventually constructed the body of the structure, the ‘bottle’ part of it, first by revolving a sketch about a central axis. Next, I designed the pipe by sweeping a circular design about a specified contour that I thought would be appropriate. Then, using SolidWorks’s Combine feature, I subtracted the pipe from the body, in order to leave a gap for when I made the pipe hollow. Next, I replicated the pipe so that I could maintain its shape in the structure.  Then, I hollowed out both the body and the pipe, remembering to leave them at least the recommended 1mm thickness, while still trying to accommodate the other design specifications for size. Finally, I filleted the interface edges in order to produce a smoothed appearance, also cutting some internal geometries to make them fit just right. In the end, I realized that this design exceeded the height restriction by two whole inches, so I tried to redimension the relevant aspects, but this resulted in some inconsistent geometries that, no matter how hard I tried, I could not rid the structure of. After a lot of tinkering, I resolved to just re-do the entire design because that would be more time-efficient. This time, I made sure that the design met the size specifications in all aspects. Additionally, I purposely neglected to place an extraneous hole in the body of the object because I thought it would be fully feasible to drain the finally printed object of any internal support material through careful spatial manipulation upon removal from the chemical bath. The first picture below is of one of my abandoned primitive designs; the second picture is of the first iteration of my finalized design; the third picture is of the properly dimension Klein bottle. Also, I included a section view in order to account for the structures of the internal geometries.

Next, I converted my SolidWorks Klein bottle Part to an STL file, put my new Klein bottle file on a flash drive, and took it to Danny Blacker. Danny took me to the WetLab to use the 3D printers. While in there, I asked Danny whether he thought I should put a hole in the bottom of the Klein bottle to facilitate the draining of support material. He told me that he didn’t think it would be necessary as the structure already had an opening through which the support material could flow after the chemical bath; he also thought that it would seriously disrupt the integrity of the concept I was trying to design. I agreed and left the design intact, although Danny did emphasize that the final product would likely need to go into the chemical bath  many times in order to gradually drain the support material out from the body. Danny then took my STL file to the computer and sent it to be printed in the Fortus machine. For the sake of conservation of the base plates that the Fortus machine printed on, my project was printed along with Harrison’s.

I was not around when the Fortus machine finished printing, but I was told that the part was put straight into the chemical bath, so I did not get a chance to see what the Klein bottle looked like with all of the printed support material included. However, overnight (i.e. to Danny’s surprise), someone must have removed the Klein bottle from the chemical bath too soon. This resulted in all of the outer support material being washed away but all of the internal support material remaining. So, I was able to take a couple of pictures of this before Danny put the part back into the chemical bath, as shown below. As can be seen from the honeycomb-like structure visible through the hole in the bottom of the body, the internal support material did not all dissolve away, so more time in the chemical bath was necessitated. Periodically, over the next few days, leading into this week, I went back to the WetLab to check on my Klein bottle. The product must have been through the chemical bath something like 7 or 8 times by the end. After a while, it became slightly difficult to determine whether the object needed more time in the chemical bath, but I used my best judgement through a variety of methods that included holding the pipe up to a bright light in order to see if there were any translucent blockages and prodding the open end of the pipe with paperclips, pipe cleaners, wire, and paper towels in order to determine if there was still any support material in the Klein bottle.

 

When I was fairly certain that there were no more significant chunks of support material in the Klein bottle, I filled it up with water to clean it. Here, I encountered yet another problem, namely that the surface tension of cold water was so great that the water had a tough time leaving the pipe. So, I filled it with hot water instead, and this came out much easier with some vigorous shaking. As a final way to ‘ensure’ that there was no significant amount of water left in the Klein bottle, I made up my own, extremely primitive, centrifuge (see below) to force out the remaining water. Basically, I tied one end of a string around the loop in the pipe, tied the other end around my fingers, and then swung the Klein bottle in circular arcs at moderate velocities (the swinging is not as easily apparent from the picture below). This all gave me some pretty interesting ideas on the practical applications of a larger sized version of the 3D printed Klein bottle as a portable potable beverage container for travellers as it would keep the drink contained only insofar as the traveller would desire. Of course for the storage of more fluid, a larger body and a larger pipe would seem more necessary.

 

After draining the Klein bottle, I looked for ways to smooth out the visible and tactile grains that were left over from the 3D printing process. I remembered that Dr. Wettergreen had mentioned some method that involved submerging the object in alcohol, so I decided to look into this. I found many sources that suggested placing the 3D printed object into a container, adding a spoonful of acetone, and then heating the container to around 110 degrees Celsius in order to vaporize the acetone. After leaving the object in the jar of vapor for a few minutes, the object typically gained a sleek, shiny look. I talked to Dr. Wettergreen about using this method, but he thought it would be too dangerous, so I resorted to just using good old-fashioned sandpaper to wear away and smooth out the grains of the Klein bottle. I first started with a coarse sandpaper that was on our worktable. When I had removed most of the roughest edges to my satisfaction, I went back over the entire object with a fine aluminum oxide sanding strip from the tool table. It didn’t take me very long to realize that the sanding had to be done in a specific direction (across the layers of filament from the 3D printing process) in order to gain the most fruitful results. Overall, this smoothed out the entire ‘outside surface’ of the Klein bottle quite satisfactorily, although there was one part within the loop of the pipe that I was not able to smooth out as well, due to the concavity and curvature of its geometry. Ultimately, although some of the grains were still visible, close inspection in a bright light made me think that just miscellaneous dirt has occupied and filled in all of the gaps in the grain. Even after washing, this smooth fill sustains.

Thus, I ended up with a relatively smooth Klein bottle. Although I couldn’t show it in pictures here, I thought it was really cool to put it up to my phone’s flashlight in order to see the intricacies of what was in the Klein bottle.