When first using the milling machine, the x and y axis were not aligned properly to the part. Although, the display was giving the correct values, the machine uses values by reference. If the reference values are incorrect, it will drastically amplify as new holes are created.
As you'll see, the majority of the errors are actually from 3D printing. This is because of many things to keep track of such as material strength/weaknesses, part accuracy, tolerances, printer settings such as extruder/bed temperature values, layer thicknesses, and bed leveling. For context, this was the first time anyone in the team used a 3D printer.
This was the original shoulder to spine joint. When testing the flexibility of the print, the joint easily broke across the perpendicular layer. This is due to PLA's properties of having a lower tensile strength to other types of 3D print materials. Another reason for the failure is due to the distance from the center of the joint. The greater distance causes a larger torque to be applied. The combination of the two weakness caused a dramatic flaw in the print. This is the primary reason why the design was changed to have a smaller distance from the center and why the material was changed to PETG.
The hole was not aligned properly which resulted in the hole not lining up.
The tolerances were too high(+.20") and resulted in a very loose fit.
A significant issue that arose was the feet traction. This is important as it's how the end effector contacts the floor. The primary issue was the material selection and how it adhered to the foot. I had found several rubber materials that would be moldable and fit the contour of the foot. This meant the selection of the adhesive was also important.