Construction

Regarding the o-ring (Drawing #JJM-55-003). The purchased o-ring cord stock was cut to length using an o-ring kit and fused together using super glue. However, the first length that was cut was too long, and cutting the extra cordage off would prove to be difficult with the equipment on hand due to the need of a perpendicular cut. With having little material to work with, this was difficult to achieve. So, taking into consideration, extra cord stock was purchased to allow for error, a new length was cut off instead rather than taking a risk to cut down the previous attempt. The first error when constructing the o-ring derived from a sub-optimal way to measure the length of the o-ring. A measuring tape was used, but due to the inability to mark the spot, when the cord was placed in the o-ring kit, it was difficult to maintain the desired location for the cut to happen. Resulting in a longer cut than desired. However, a change to the design of the Front Screen was made. Giving the rounded corners a larger radius to allow for an easier transition for the o-ring at the corners. With this change, the previous made o-ring is no longer viable, because the perimeter of the Front Screen has been changed. So, a new o-ring has been made to compensate for this change.

O-Ring

Figure: O-ring construction

Test Frame

To ensure the design of the phone housing was adequate, a model was made specifically for 3d printing (Drawing #JJM-20-003). Features from the aluminum phone housing were translated over, with the only changes being in regards to the fastening of the two halves. A designated area was designated for standoffs to allow for construction. The prototype was printed using PLA+ for added rigidity and the print took approximately six hours. 

Front Screen Reference

For the Front Screen Reference (Drawing #JJM-20-004), first a piece of stock was cut on the bandsaw then machined to size using a milling machine. This will allow less material to be wasted, as well as insurance that a clean part will be manufactured. 

The piece of stock is then loaded into the CNC mill was it was properly sized, and squared on the manual mill. The x, y, and z axis were all determined based on the origin chosen in SolidWorks, as well as the tool height. The tool path for this part was completed using SolidWorks. 

This is the result of the finished part. This part was made to help gain an understanding on the feeds and speeds needed to machine specific features needed for the assembly. Further work will be needed to remove excess stock from the bottom, however this can be easily accomplished using a manual milling machine. 

Construction Summary

The construction of the eco-friendly smartphone housing involved assembling two main aluminum parts, screws, and an o-ring. To assemble, initially the o-ring was fitted into its slot on the phone's frame, followed by aligning and attaching the back plate with screws, ensuring a secure assembly.

The design included a front screen that incorporates future screen integration and an o-ring gland for protection against water and dust. The back plate, designed for easy removal, enables users to replace components. Screws made from 18-8 stainless steel with an EDPM o-ring ensure a dust and water-resistant seal. A 3D printed prototype facilitated early testing and design validation.

Parts were manufactured in-house and sourced, with a focus on CNC milling for precision. A new part introduced on January 22, 2024, aimed to optimize the CNC milling process. Manufacturing encountered delays due to the complexity of part features and tool path design, extending beyond the anticipated timeline.

The assembly followed a systematic process, resulting in a device that offers robust protection against environmental elements and allows for easy disassembly. This project demonstrated engineering precision and practical design, achieving a balance between simplicity, cost-efficiency, and manufacturability, setting a new standard for eco-friendly smartphone housing.

Figure: 3d Printed Test Frame

Figure: Front Screen Reference Stock

Figure: Front Screen Reference Set Up

Figure: Front Screen Reference 

Figure: Drawing Tree

Front Screen

This is the result of the finished part. This part was made using the CNC milling machine at Central Washington University. This is the first prototype for the Sustainable Smartphone. The only errors encountered were scheduling conflicts due to backlog of the CNC milling machine. 

Figure: Front Screen

Back Plate

Figure: Back Plate - Ceramic Resin

Because the backplate couldn't be manufactured on the CNC milling machine, alternate methods were researched to manufacture the part. The first solution was to 3d print the part out of an experimental ceramic resin. However, since the resin was experimental the print failed. The material was too flexible and the features were not accurately produced. 

Figure: Back Plate - 3d Printed Aluminum

Figure: Back Plate - First Assembly

Since the ceramic resin failed, alternate manufacturing methods were researched. Eventually outsourcing the part to get it 3d printed in aluminum was chosen. This was chosen because it would have the rigidity desired from aluminum, and accurate dimensions due to it being 3d printed. This was a successful part. 

Sustainable Phone Housing

Figure: Final Assembly - Deconstructed 

Figure: Final Assembly 

Heading into the testing portion of the capstone project, there was a need for multiple prototypes due to destructive testing. Whether by the device being subjected to forces to assess its ability to withstand the forces, or submersion tests where the aluminum could corrode. So the parts were outsourced to PCBWay where multiple prototypes were produced with an anodized coating. This was done because the engineer did not have time to manufacture all the needed prototypes.