2017/04/19 - Good News, Bad News

This week has had a lot of positive advancements, but a lot of setbacks as well.

After last Wednesday's class, I met Mr Youseffi to pick up the small clamps. In order to try counteracting the x-y decalibration, we tried a newer 3d printer. We also oriented them in different ways to see if any orientation would work better (ie x vs y axis orientation and flat side up vs flat side down) to see if it would make any difference. When I measured them at home I found that the dimensions along the flat surface was the perfect 1.05", meaning that the x and y servos were in perfect order. however, along the z axis the combined clamps had a total distance of 1.08", making for a difference of 0.03". Although I was planning on filing the 1.05" diameter a little to let it fit smoothly into the PVC pipe, when I tried to do so with this 1.08 effective diameter I realized that going through the extra 0.03 inches with my hand file was making the surface excessively distorted and uneven. Nonetheless, I made a revision to all of the clamp parts by changing the 1.05" diameters to 1" with the idea that with the smaller size, I could just warp it with blue tape until it can fit snugly into the pipe. Finally, I sent Dr Youseffi these new versions, and hopefully I will have the results today.

The clamps were not the only thing I worked on today. Over the weekend, I worked on dramatically refining my laser cut acrylic pieces and patterns. for starters, I completely removed the 1 piece 2D brackets and the complicated connection system. For this new version, I made it so that the brackets would be composed of  1"x4.5" and 1"x.75" rectangles with holes for screws, Rails for the 1/12 scale car with a cross sections of 0.25"x1.5" and two sets altering 0.25"x0.5" upper support beams, all of which would also use the screw system. The assembly would look something like the blue lines image shown below (which is super imposed over the 1/12 scales groups's existing bracket. However, I will need to devise a way to connect it to pvc pipes and make the upper portion of my braket (keeping the two support beams spaced evenly. In addition, I've also included my current draft for the laser cuttout pattern.

Sadly, my progress with the laser cutter was not as productive. On Monday I was informed that due to a conflict with the laser cutter's driver and modern Windows, the computer that was supposed to be dedicated to the the laser cutter no longer works and so I re downloaded the drivers for it. On Tuesday, I spent two hours attempting to get the lab laser cutter to work with my laptop, but it was a complete failure. As such I contacted Dr. Barez about his departments, laser cutter, who told me that I should contact Dr. Obi, who also told me to contact Mr. Peters and Mr. Meininger.

2017/04/12 - Wood, Acrylic, and ABS

This week, I had three main focuses: milling the wood bars to have the triangular slits, refining the acrylic brackets and guide-way as well as manufacturing the smaller horizontal and vertical clamps. Although the first one went perfectly, the other two did not go quite as smoothly as desired.

My dad and I, milled the wood sections went perfectly well. We made 1/4" by 1/2" triangles on a 1"x1"  wood bar and a 1/8" by 1/16" triangles for multiple 5/8"x5/8" wood pieces using a 45 degree router bit. In addition, we also used a 1/16" radius router bit to round the corners on the 5/8"x5/8" router bits so they can better fit into the clamps.

Figure 1

For the acrylic parts, I realized that the sample bogie would not be able to clear the PVC pipe as shown below in Figure 2, and so I attempted to redesign the connector parts  so that it would hold the support beams from above instead of from the center, and it would have offset edges allowing for altering connections (Figure 3)- however these alternating connections would likely be too weak and needlessly complicated. In addition, the bracket itself would also bring problems - the way it is only made in a 2D plane would make connections to both the support beams and bogie rails be too difficult as well, and the cutout area takes up too much space.

Figure 2

Figure 3

For the 3d printed parts, the problems were in the the dimensions of the smaller diameters (where the pvc pipe would connect. In my first T-clamp print I noticed that the  between the nominal diameter (of 1.05 inches) and the effective diameters of 1 in on the vertical and 1.06 on the horizontal sections. On the second version, I realized that the measurements of these were inversed. I presume that the reason why is that the two iterations of clamps were oriented 90 degrees from each other, and one the x-y servos must be decalibrated. In any case, I used my default dimensions for the small clamps shown in figures 4 and 5.

Figure 4 and 5

2017/04/05 (and 2017/07/29) - Physical Models and Refinments

During the last two weeks, I did a variety of things for the super way project.

The first thing was to mill the 2x2" wood into 5/8x5/8" and 1x1" pieces. With this and a segment on 1" schedule 40 pvc pipe, I could properly test the existing pair of clamps. With some sanding on the corners, the 5/8x5/8" wood fit perfectly, but there was some issue with fitting the pvc pipe on the horizontal part of the clamp.

 

Next, I refined the design of my clamps. Specifically, I modified a several of the length dimensions, and then added flaps to the bottom of the T clamp while pushing them out by 1/8 of the edge, which would allows laser cut acrylic parts to be placed within. I also changed the diameter of the horizontal parts of the clamp so the next model would be able to accept pvc pipes without filing it down. Finaly, I merged the different types of clamps into one Soldworks document (by using the suppress feature to allow changes between the different types of clamps), so that making modifications would be a lot faster and simpler.

Likewise I made a first draft template for the laser cut part. The acrylic sheet will be used for many different types of parts, such as the trusses, the upper horizontal support beam (which will allow additional modifications such as for the solar array), the guide way connecters and beams as well as the brackets (based on those made by the 12th scale group). Though not yet designed, it will also be used to make the guideway rails. 

The end result for one of the two support columns will look like the picture below, , though there still will need to be significant modifications to the guide way parts

Finaly, I also worked on the presentation for today. In addition, I also should mention important to mention that I did an essay for ME 195B on the Three Gorges Dam and its societal and cultural effects.