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Thermoforming Factory

For the product I’m building (A portable electronic scoreboard), the enclosure is large; 18″x10″. This is pushing the limits of injection molding without using a giant press. It’s certainly too large for a 50 ton press, and the 200 ton is about right. I was looking for other options and wanted to try out thermoforming, which is also called vacuum forming. The theory is that you heat up a sheet of plastic, drop it over a mold, and then suck the air out between the plastic and mold so that the plastic gets sucked to the mold.

This is a much cheaper method of production, as well, because the tooling is much cheaper and easier to make, and the temperatures and pressures required are much lower. It is better for prototypes as well, because you can make a mold out of anything, including styrofoam, and get an idea for the feel of it.

Vacuum forming isn’t perfect, though; it’s only good for making shells because you are starting with a sheet. And the formed part still needs a lot of work afterwards, cutting the excess material around the part, adding side holes, sanding. There are tradeoffs, and I wanted to explore this option.

I managed to find a factory, though it turned out they didn’t do the thickness of material I wanted, or the type of material I wanted, and didn’t even have the machinery I needed. It was also a challenge showing him the design and telling him it was a prototype, and that I could make changes to make the design more manufacturable. There is definitely an expectation with factories that the designs you show them are set in stone and you need exactly what is on the paper, which has been a challenge for prototyping in China.

The trip wasn’t a total loss, though. I managed to get some photos and video of the process. This factory makes blister packs mostly, and packaging for bulk transportation of products. They use cheap thin materials and while fairly basic, they get the job done pretty well.

Permanent link to this article: http://engineerinshenzhen.com/thermoforming-factory/

1 comment

  1. Jean

    You design is really cool!
    I had the idea of a large digit display last week, when I read about the Canadian student demonstration and the stupid law their governement passed to prevent gatherings of more than 49 people (I think it was 49, but I’m not super sure). Anyway, I watched a video about how the demonstrators shoud organize and how gather into groups of less than 50 people. Having a big display board you could
    show up you head, with the number of people in the group, would be great and ease the organisation. I went on eBay to look for “cheap digit display” but I didn’t find anything below $100.
    That’s just an idea, but there’s definitely a room for a ‘not too
    expensive’ panel like yours!

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