3D-Printed Components:

There were only a few 3D-printed components in this build. To constrain most of the ground links, mounts were printed with many holes for fasteners. These designs at a glance look like they are over-constraining the system, yet this design is justified due to the massive load on the end of these cantilever-like links. Some of the other 3D-printed components include the pitcher mount and cup posts. The pitcher mount is adjustable and uses a hex bar design to rotate the pitcher and then constrain it in its final position. The posts were included as a last-minute method to tip the coffee cup to a certain angle which allows the pitcher to pour milk without interference with the lip of the said cup.

Figure 1. Ground link mounts

Figure 2. Pitcher mount

Laser cutting:

All of these components were cut out of ¼” wood which was a good thickness to help support the milk pitcher. The links were cut so that their joint holes allowed bearings to be pressure fit without using something like an adhesive. The back and ground plates were mainly held together by a square fit. Also, there were cuts in the ground plate for vertical beams to support the ground links. Also, the back plate has cuts and holes for the ground link mounts. The ground links went through some iterations; the final designs have a mounting flange that adds even more support to counteract the force of the pitcher. Lastly, diagonal struts were placed at the base of the back plate to add even more support. The first iteration of the motor mount was made out of PLA, but we decided on using plywood because it is much faster to manufacture.

Bearing press fit links

Figure 3. Image of links

Backplate and ground plate

Figure 4. Image of back and ground plates

Ground joint bars, struts, and vertical supports

Figure 5. Image of ground links, struts, and vertical supports

Motor mount

Figure 6. Image of the motor mount

OEM Parts:

The shaft collars were purchased for precision constraint on the links to keep them tightly inline. The metal couplers were purchased to adapt the 5mm shaft of the potentiometer and motor to an 8mm shaft that drove the pulley and belt system. These components were critical to the design due to their precise tolerances and rigidity.

Shaft Collar

Figure 7. Image of one of the shaft collars

Pulley, Belt, and Coupler

Figure 8. Image of pulley, belt, and coupler

Assembly:

Figure 9. Right isometric view of the final physical assembly

Figure 10. Left isometric view of the final physical assembly

As you can see, the final physical assembly integrates all of the components listed above in this complex machine. The manufacturing process for this assembly was quite convoluted though the results of this work allowed us to achieve the motion we desired from the beginning of our design process.

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