Custom vacuum forming services by Productive Plastics, a leading vacuum thermoforming contract manufacturer. The vacuum forming process is a plastic thermoforming process that uses vacuum to pull a heated plastic sheet against a mold to make components. Product design and vacuum forming manufacturing engineering assistance are available. Vacuum forming is a manufacturing process by which a sheet of plastic is heated and pressed over a form to create a part. A 3D printed part is a great way to create low-cost molds for low volume manufacturing or prototyping. In this guide, we'll cover the best practices for achieving this using 3D printing.
Vacuum Forming is a process used to mold plastic into a desired shape. A thin sheet of plastic is heated to a soft state and then air pressure is used to press the plastic down around or into a mold. Vacuum forming can be used to make a variety of items, anything from product packaging to bath tubs.
That being said, a vacuum former is probably one of those things that would be nice to have around but may not get a lot of use. Therefore, spending any significant amount of money on one would result in a low-value situation. For some folks, building one from scratch may be the way to go. [Amalgamized] built his own low-cost vacuum former and did a great job documenting the build.
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There is a two-pronged attack to keep the costs down on this project. First, the frame is made from readily available materials that you probably have kicking around in your wood scrap bin. The sides of the frame are 3/4″ plywood and the hole-filled top is made from 1/4″ MDF. A piece of PVC pipe connects the chamber below the top piece of MDF to a shopvac. The shopvac pulls the air down through the top’s holes; think reverse air hockey table.
Attack prong #2 is that there is no dedicated heater. Binder clips secure the plastic sheets to an aluminum window frame which are then put in the oven for a few minutes between 250 and 300ºF. When the plastic starts to droop, it is quickly removed from the oven and placed over a mold. The shopvac creates a low pressure zone under the plastic and atmospheric pressure pushes the plastic down around the mold.
I was ready for my first test. I grabbed some random objects and arranged them on the platen.
I was using some Sintra plastic (expanded PVC) for my vacuum forming I had left over from a few years ago. I think it's about 2-3mm thick. I clamped it inside the frame and heated it up with my heat gun for a few minutes until the whole piece was very flexible. (While writing this Instructable, I also learned that Sintra can be softened by submerging it in boiling water for 10 to 15 seconds, which seems like it would heat it more evenly). When the Sintra is fully heated, turn on the vacuum cleaner and place the plastic over your objects onto the platen. The plastic will stretch as it lays over the objects; when the frame touches the platen and creates a seal, the vacuum will be able to suck the plastic tightly over the pieces. Make sure to bring the frame straight down rather than from the side, or you may stretch parts of the plastic and cause it to tear. I found if the plastic does not pull as tightly over some parts as you would like (either because the plastic was not heated enough in that spot, or because the vacuum is not strong enough), you can heat it up some more with the heat gun as the vacuum is still running. With plastic as thin as I was using, it was really easy to burn holes through the plastic if I heated up a spot for just a split second too long. Comments are closed.
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