Wednesday, January 8, 2014

prosthetic hand: milwaukee prt.5

I printed the new finger (> last night and put it together this morning. I printed this at a smaller scale than the last fingers because I believe that will be the issue that we will run into with these recent designs. There comes a point where the linkage pieces will have to be too small (thin) to accommodate such a small finger. This finger is 80mm from tip to end; right before the last back segment where the cable is routed through.  I used much smaller pins cut from steel tig welding rod and glued the ends with epoxy to keep them from falling out. Overall the print came out well. It was necessary to boost the infill due to the small cavities that weaken the segments around the passageways for the linkages (I printed at 50% infill). There is an obstruction in the first joint caused by the small linkage hitting inside. I also had to file the interface between the second and third link a bit to get things to be fully seated in the fully straightened position. After printing this and assembling this, I'm not sure how much smaller I would want to go. Of course this will be where some design work can be done to accommodate for this. 

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