DIY Ultrasonic Plastic Welding

Here’s something that may be of interest to all the reprappers, vacuum formers, and other plastic fabbers out there: ultrasonic welding of plastics. If you’ve ever wanted to join two pieces of plastic without melting them together with acetone or screwing them together, [circuitguru] is your guy.

Ultrasonic welder setups are usually reserved for companies that don’t mind spending tens of thousands of dollars on a piece equipment. There are smaller versions made for heat staking – melting plastic pillars into rivets on the work piece – and [circuitguru] was lucky enough a somewhat reasonable price.

Because the heat staking gun was a handheld unit, a rotary tool drill press was put to work. The end result is a relatively inexpensive way to join two plastic parts without screws, glue, or solvents. The bond is pretty strong, too. Check out the video after the break to see [circuitguru] join two pieces of a plastic enclosure and try to tear them apart.

40 thoughts on “DIY Ultrasonic Plastic Welding

  1. Is this what Sandisk seals their flash drives with? I’ve taken to using a paper slicer or a hacksaw to open them now because I’m tired of getting shanked by plastic shards.

  2. I’ve been wondering if the ultrasonic transducer from an ultrasonic humidifier could be put to exciting use like this. I suspect it can probably put out enough power to do a little ultrasonic welding, and you could probably build your own amp/signal generator if the setup for humidifying isn’t appropriate to welding.

    For that matter there are probably some tweeters out there that could go high enough to weld or do other ultrasonic tasks

    1. The ultrasonic welders I have seen are pretty big, the power supplies that drive the ultrasonic horn are about the size of an ultrasonic humidifier itself. So no, I don’t think it will work.

      You might be able to start out with a used ultrasonic driver for a big US cleaner tank. I see those go for cheap.

      Bad thing about ultrasonic welding is they can create a of noise when putting inserts in. Makes finger nails on a chalkboard sound pleasant.

  3. Agree, all his DIY stuff listed is quite honestly pathetic, all he’s listed is stuff he’s bought. Why don’t you make your HD camera, that would be DIY.

    I was also disappointed in this. This is just re-using something, not really DIY except for using a pre made drill press for a mount.

  4. please define … DIY … it just seams like he made a mount for a drill press for something already advertised as a plastic welder … also may i add these are far from cheap
    it cant be THAT hard to make your own high frequency welder they have been around seance the 40s

  5. Look into the TIDE BUZZ stain remover pen. Unmodified I can weld styrene sheets easily and re seal bister paks. I have considered making a sonic screwdriver out of Buzz parts.

    1. That is some bit of really interesting information! What thicknesses could you weld and what materials? I was looking for a solution to weld plastic foils for quite some time now and would buy the device (is it that one [0]?) right away if it was not for the heavy shipping and taxes to europe.
      It would be great if you could provide more details so I can be sure not to waste 70$ on a useless device.


      1. Check if the following is true:
        * Does it make a buzzing noise?
        * Does it start to glide easier over surfaces if you press the button?
        * Does it feel weird and get hot if you touch the tip with your finger (actually do not do that, it can hurt a lot)?
        * Does it turn water into mist if you touch the surface of some water with the tip?

          1. I remember there was a sensor which only let you activate the ultrasonic module if the water pump is activated. Sometimes this sensor could corrode and then you can not activate the ultrasonic module at all. Because this annoyed me I opened the thing and short-circuited the sensor. Maybe you just open it and see what is going on. The electronics was not that complicated …

        1. Ah-ha! Yes, it does need to have liquid in it. I even read the instructions, but don’t remember seeing that detail. Now it buzzes. It barely makes a mark in a thick piece of plastic, but a very thin heat-stake will indeed be squashed. Many thanks!!!

          1. Awesome! Try different surfaces to work on (I remember metal working quite good) and use a ruler if you want to make strong and straight seams. What is you project btw?

        2. My project is assembling circuit boards into cases. The gizmo makes a sound that helps autistic people learn better. (there’s a picture on the “ordering for home use” page but I didn’t want to link straight to the commercial page.)

          I did the injection molds for the cases, and the circuit board design… in fact the whole thing. The concept isn’t mine but the engineering is.

  6. well … if u want to try there is the ultrasonic cleaner made for jewelary and glasses i bout it used for 10 $ , it sold new in range 30 -50 $ , u can built the generator by urself cuz mine has a fixed frequency and i’m sure it will work much better than any ultrasonic pen either buzz or even dental one , its about 10 cm x 15 cm , and yes it make a buzz noise and make wierd feeling when u touch and it mist water when turned on m it even destoy a foil sheet and make strange wholes in it . but didnt try it yet on plastic .. i think this might help

    1. Too bad the site isn’t around anymore – would have been interesting to see more. And there aren’t more than 2 videos on his Youtube account which looks abandoned.

      It’s interesting to see this kind of welding. Had no idea it could be so resistant but from what I saw, it’s pretty strong. Wish there was more shown in the video – too short for such a thing.

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