2. Design Procedure

In order to reduce friction in the joints of the linkages, we choose to use ball bearings. We initially were going to sandwich the bearings in-between the linkages using nuts, washers, and screws. However, after playing around with this technique we realized the discrepancy between the thickness of the linkages, made of 1/4" wood, and the ball bearings created too much play within that cavity and led to a loss of robustness. It was then that we decided to go with press fit which worked much better than our previous technique. After experimenting with various press fits, we decided that a threshold of +/- 0.03 millimeters would yield a strong and reliable press fit.

We initially laser cut all linkages from acrylic. However after seeing how flimsy and unreliable they were, we immediately switch to wooden linkages. The only part that stayed acrylic was the slider that connected to link 6 (see kinematic analysis). Our reason for this is that wood sliding on wood may introduce large amounts of friction which can be avoided by simply using acrylic for the slider.