Objective

My undergraduate technical thesis team designed a vacuum thermoformer to support the main deliverable of our capstone project. The vacuum thermoformer is able to mold plastic into the shape of the item on the tray below it and we used it to mold a plastic face shield for a Powered Air Purifying Respirator (PAPR). The requirements for the project were that our team was to add new innovations to the thermoformer beyond what had been previously completed in reference projects and to make the device easy to use. The performance of the thermoformer was determined by testing whether it functioned as it was designed.

Process and Technical Details

The vacuum thermoformer was initially intended as a way that I could make a contribution to my teammates who were working on the PAPR. I researched vacuum thermoformers for reference and presented the idea to my team and professor. My professor suggested tools and materials that we had access to including a milling machine, metal band saw, and angle bars. Then, I outlined the basic functional requirements of the thermoformer as well as researched the major components including the vacuum pump, plastic sheets, and space heater. Next, I modeled and assembled the parts in Solidworks. In the process, I worked with one of my teammates to create constraints on the model for animation and included screws, washers, and nuts in the assembly. We ordered all of the parts and when they arrived we cut and milled the angle bars to length and drilled holes for the screws. Our entire team assisted with assembling all of the parts including a 1500W space heater, a ½ horsepower vacuum air pump, linear actuator, and linear guide rails.  Some of the challenges for the project included ensuring tolerance fits and that all materials could safely function with a 350 ℉ heat tolerance.

Results

The vacuum thermoformer successfully worked on the first try. It melted a 24” x 12” sheet of 3/8” PETG plastic and formed the plastic into the Iron Man mask shape below it. We met the requirement of innovation with multiple updates. The most prominent of the innovations was using a linear actuator to move the space heater over the sheet of plastic to melt a larger surface area. Additionally, we used linear guide rails to smoothly lower the tray, toggle clamps to hold the plastic sheet to the tray, and quick-release connections for all of the hose lines for ease of use.