Hello,
After our first prototype (discussed in the previous blog post), we realized we made some critical mistakes. This post will discuss our next attempt to print a full motion Bucky.
Second Bucky Prototype (Bucky V2)
Printing Parameters (Ultimaker 3):
Print Material – PLA
Support Material – PVA
Layer Height – 0.1 mm
Infill Density – 25%
Number of Shells – 2
Joint Gap – 0.2 mm
For our second prototype we made three significant changes. First, we increased the number of shells printed from 1 to 2 in order to provide a more durable Bucky. From our previous work, we discovered that regardless of the gap size (from 0.1 mm to 0.4 mm) on the joint, there will be some plastic that is still bonded together. The joints need to be broken loose before they can be moved freely. This extra shell helps prevent the appendages from being broken off during this process.
Second, all of the appendages were offset from the torso by 0.2 mm in an attempt to prevent them from fusing together during printing.
Third, the balls of the ball-and-socket joint were moved from the torso to the arms. This allowed us to make the ball a little larger (and stronger) than with the ball located off of the torso.
Figure 1: Sliced view of Bucky V2 with the ball shown coming off of the arms
Good news – it worked! All the joints on Bucky moved. The arms were a little more loose than we liked, but the head and torso were functioning great. The print quality was consistent with the first print, and no post processing was required other than the water bath to remove the soluble support.
Figure 2: Build-plate Bucky before removal
In the next post we will discuss our attempt to remove some of the slack in the joints for a more controlled range of motion.
Thank you for reading!
Team Bucky