Project Overview
This project is a complimentary design to two of our group members’ capstone project, using different polymers to create dishwasher safe retainers. This project will be an enclosure, that is also dishwasher safe, and can hold both retainers (top and bottom) separately. It will also allow for a proper cleaning cycle while keeping the retainers in a separate environment from all other objects in the dishwasher. This enclosure will be able to withstand the harsh environments of a dishwasher with repeated uses. Polycarbonate has been chosen as the material because of its reliability in previous capstone testing. The Ultimaker has also been chosen for this project, meaning one consideration will be the inclusion of supports for the middle section. This object’s functionality will be tested after the first print during our group members’ capstone testing.
Preliminary Design and Manufacturing Considerations
The design of the enclosure itself has two compartments, one for each retainer (top and bottom). Each compartment will have meshed outer walls to allow penetration from the dishwasher detergent and enable proper cleansing to be accomplished. These two compartments will be separated by a thicker wall that will also have a meshed surface. Again, the design will allow for detergent to enter from any direction, not hindering the cleansing process. The mesh will ideally be in a honeycomb pattern for structural advantages, however, it will abide by what the machine is capable of printing.
Along with the separated compartments and meshed walls, the enclosure will also include outer walls that will be on hinges and also can lock, making sure the enclosure does not open and the retainers can not spill out. These walls will also be meshed. Along with the design, a few manufacturing considerations pertain to these locking walls. The hinges most likely cannot be additively manufactured from a single piece, so two separate prints are being considered for these walls. One idea is to make snap-on hinges, which will mean both the enclosure and the out walls need to have a male and female part for the snap on hinges. This is a very popular design for 3D printed objects and a very feasible option for this project. This same idea will be applied to the locking mechanism as well.
Another design consideration is variable based on the average dimensions of someone’s teeth. Our group has many retainers that were thermoformed for another capstone project. The dimensions for the enclosure were based off these measurements. The preliminary design is 3.5” x 4” x 3.5”.
The figures below will include the preliminary design drafts as well as an example of snap on hinges from a 3D printed project.
Material Considerations
The material used to create this enclosure must be able to withstand the temperatures reached during a dishwasher cycle. A normal dishwasher cycle can reach up to 75 oC [2]. This means that the polymer used when printing the enclosure must have a glass transition temperature higher than 75 oC. Since the Ultimaker will be used for this project, the available materials are PLA, ABS, nylon, CPE, PVA, PP, PC, and TPU. Only two of the listed materials have a glass transition temperature greater than 75 oC are PC and ABS. This project is related to two group members’ capstone project, which involves testing several materials for a dishwasher-safe retainer. One of the materials that has been tested is polycarbonate, which has been proven to withstand dishwasher cycles. For this reason, we will propose the use of the PC Ultimaker print for our enclosure.
Proposed First Print Trial and Experimentation
The first print trial will be an attempt at creating the enclosure with the Ultimaker 3D printer. The first trial will optimize the support structure.The trial will also look for the best mesh wall structure for the polycarbonate enclosure. The proposed plan is to compare a honeycomb mesh structure to a square mesh. Three parts will need to be printed separately: the two faces of the enclosure that open and the enclosure body. See Figure 3 for a drawing of the three separate prints.
This enclosure can be put into the dishwasher with retainer samples to test how the object and material withstand the harsh environment and if any deformations occur. This will also be able to test how the dishwasher can cleanse the retainers properly or not as this will be a direct application to the other group members’ capstone project.
Austin Schwark, Shianne Carroll, Nick Pocquette, Riley Cockerill
References
[1] 3D Printing Joints, https://coloringchaos.github.io/form-fall-16/joints,
https://removeandreplace.com/2016/03/24/what-is-the-best-water-temperature-for-dishwasher/,
March 3, 2019
[2] What Is The Recommended Water Temperature For A Dishwasher,
https://removeandreplace.com/2016/03/24/what-is-the-best-water-temperature-for-dishwasher/,
March 3, 2019