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