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Granulator MK II OSHE
Background and Introduction
This project was developed mainly by Walker Nelson Peter Gorecki, who finished their capstone design project through Michigan Technological University in 2016. Since its publishing, the Granulator design and assembly itself has not changed, but information regarding the power consumption while granulating different thermoplastics has been researched. This Wiki page contains a link to the website where the project files and initial description are hosted, and updates for this project for the future.
All relevant files
As said in the Background and Introduction; all files (CAD, construction, report, simulation) can be accessed on this site
Files relating to power consumption, or noise reduction are located on this page
Work done on the Granulator MK II in the spring semester of 2019 can be accredited to Sean Scsavnicki, Arvind Ravindran. Faculty who aided this project during this time include Shane Oberlier and Dr. Pearce.
With the aid of Shane Oberlier, an open-source printed circuit board and arduino nano were attached to the power supply to measure the power output of the granulator MKII while it was processing different materials. During each of the power recording sessions, thermoplastic was inserted at a rate the granulator MKII can handle. This rate is not measured, as it highly depends on the geometry of the inserted plastic.
This data was processed and its results appear below in a table
|PLA (Polylactic Acid)||ABS (Acrylonitrile butadiene styrene)||PETE (Polyethylene terephthalate)|
|Average power consumption per hour||POWER OUT FOR PLA||POWER OUT FOR ABS||POWER OUT FOR PETE|
Recently, noise has been a big concern of the granulator MKII owing to the needs of power consumption and safety. To enhance adoption of the granulator by more people, it was decided to undertake noise control measures and make the device operate with reasonable noise tolerance.
Tests were performed to find the sound pressure levels of the granulator MKII system including the auxiliary devices such as the vacuum pump. It was determined that the vacuum pump was the loudest source with a distinct 250 Hz octave band frequency wherein the levels were significantly higher. Panel gaps in the enclosure for the granulator provides leakage paths for the sound and hence it was decided to seal these gaps appropriately. The inner lining of the walls were packed with foam to increase transmission loss between the source and the surrounding.
Using the sound data that was collected, dimensions were found for an expansion chamber that could be attached to the 5-gallon bucket shop vacuum, and a 3D model was produced to utilize the leftover PVC and a 3D printer. The CAD file is linked here, and the construction of the expansion chamber is described in this section. As 250Hz was the chosen frequency band for attenuation, the double tuned expansion chamber design was chosen as it provides good transmission loss around the frequency of interest while having good attenuation around the octave bands as well. However, the muffler aids in low frequency attenuation and by lining the inner walls of the muffler with fibreglass foam, we can achieve in higher frequency range as well.
The modifications to the granulator need to be verified with sound pressure level measurements.
Potential for recycling common thermoplastics
This semester the OSHE has teamed up with the sustainability enterprise and sustainability house to attempt to create house numbers from recycling thermoplastics, mainly PETE, or #1 recycling. The results of this project are presented in this section
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