Rotating Trivet

thingiverse

DO NOT PRINT WITH ABS OR PLA, HIGH TEMP FILAMENT IS A MUST. This trivet was created by Adam Bujnowski, Alex Kinney, and Mark Traverso as part of Virginia Tech's Mechanical Engineering class in additive manufacturing. Eastman chemical supplied the material for prototyping, this design is based on their amphora line of filament, which is PETG based. Colorfabb-XT and Taulman n-Vent are the amphora filaments available at this time. It is recommended that this design be printed with Amphora. Amphora has a higher melt temp than abs and pla and is crucial to the trivet working properly. Other PET based filament should also work but have not been tested. This trivet will work with most cookware at temperatures up to 110 degrees C. Try not to use the trivet with cookware at higher temps, eventually this will melt. This trivet was designed using heat transfer properties of truss based unit cell fins. It is recommend that this be printed face down meaning that the fins will be the top layer when printing. Using a heated bed in this orientation seems to provide a better heat resistance to the top. Thank you for looking and please share your results. Also picture is show to what happens if you use to hot of a pan. Print Settings Printer Brand: Printrbot Printer: Simple Black Rafts: No Supports: Yes Resolution: 0.2 mm Infill: 30% Notes: PET based filaments work well, honeycomb infill works well, print with a minimum of three shells. Larger ring was printed with mass portal pharaoh, other prints were better on printrbot. Turn support off for bridging if using amphora, Amphora is very good at bridging so no need for support there. Use pillar support for the sliding joint support, if using another type will be hard to remove support. I learned that the hard way. How I Designed This Thank you to Dr. Chris Williams for giving us an opportunity learn about AM and teach a fun class. For anyone thinking about taking his class (ME 4644 and ME 5644) or coming to VT, do it. A big thank you to Eastman Chemical Company for giving us an opportunity to showcase a design with your product. Existing trivets are generally a flat piece of material with simple geometry that doesn’t optimize heat transfer and convection. Another issue is that they are usually large and bulky and difficult to store within the kitchen. These two principles are the main thoughts that lead to the idea of a 3D printed solution. With additive manufacturing, complex geometry can optimize heat transfer, customized designs can be added for each customer, and the trivet can be created within the confines of the customers own home. The team decided to take on the challenge of finding a combination of design, material, and printer properties to create a viable product which will perform better than existing trivets in all aspects. After research and comparison, the material chosen to be used was Amphora developed by Eastman Chemical Company. A key property of this material is the high melting and deflection temperature, which is essential to this product. This was found to be higher than any other usual material used in the 3D printing industry. The printer that was chosen was the Mass Portal extrusion printer due to availability. With the printer and material chosen, concept generation and selection began. Many concepts with unique ideas were all considered and compared against each other, which came to the final solution of a semi-circle design. This semicircle design consists of a sliding joint around the circumference of three separate sections, which allows the trivet to expand in size. On the top of this design, there are channels cut into the pieces to allow for airflow underneath the pot, which will promote convective heat transfer from the pot. On the underside, there are complex fins added which will help to evenly disperse heat throughout the trivet and optimizing overall heat transfer of the whole system. After the final design was complete, the next step was prototyping and testing. With the parts that were printed, a thermal analysis was conducted using simulation software. The analysis showed that our trivet had a lower temperature in contact with the counter surface than current trivets by approximately 13 C, thus proving our trivet actually performs more efficiently than existing trivets. Along with the simulation, the team wanted to test the piece in an actual application. Hot pots of boiling water, as well as baking sheets, were placed on the trivet with complete success. No deformation or melting of the trivet occurred with these usual applications. A failure analysis was also conducted to see at what point the trivet would fail, so the team tested the trivet in a worst case scenario by placing an empty pan at max temperature on the trivet. This caused severe melting, warping, and also caused the trivet to stick to the bottom of the pan and require scraping to remove it. With the failure of the part, the team recommends that it only be used for pots of boiling water, light cooking, and pans used for baking since most of these uses result in contact temperatures less than 110°C. This will keep the user safe, as well as the counter or tabletop the trivet is resting on safe also.