Plastic friction welding? - Page 1
Forum section: electronics / general

author: kalel
author_rank: Frequent Contributor
timestamp: October 29, 2017, 05:13:07 pm
content: I've first learned about it from Franlab's video:The result looks really strong.Does anyone have any experience with this?I have looked on eBay/Ali to see if there's some matching item from China, but I'm not sure what would be able to fit inside of a mini drill or dremel like that.If you know another search term or product that might work, please do share. I'm just exploring the market to see how expensive this would be.

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 29, 2017, 05:38:59 pm
content: It's just a Dremmel with a piece of 3mm filament in, what's to know?I do it quite often.

author: kalel
author_rank: Frequent Contributor
timestamp: October 29, 2017, 05:50:26 pm
content: Quote from: Mjolinor on October 29, 2017, 05:38:59 pmJust how to find the right filament. Otherwise it seems simple and effective to do.

author: SeanB
author_rank: Super Contributor
timestamp: October 29, 2017, 05:54:05 pm
content: I tend to use a soldering gun and manual PWM of the tip temperature, works just as well.

author: ajb
author_rank: Super Contributor
timestamp: October 29, 2017, 08:15:37 pm
content: Quote from: kalel on October 29, 2017, 05:50:26 pmMany plastic parts will have a mark molded into them that indicates the material, so if you can find one of those, googling for the material + "3mm rod" will likely find you something that will work.If the material isn't marked, then you'll have to make an educated guess based on the part and its material properties. ABS is probably the most common material for basic consumer items and plastic electronic enclosures. Polypropylene, polystyrene, nylon, polyethylene would be other common ones.Some materials may be cross-compatible when friction welding, I suspect at the very least the melting points will need to be quite close to get good results.

author: Zero999
author_rank: Super Contributor
timestamp: October 29, 2017, 09:23:11 pm
content: Quote from: SeanB on October 29, 2017, 05:54:05 pmI've never managed to do very good welds using a soldering iron. Perhaps I got the temperature wrong? How did you manage it?

author: jpanhalt
author_rank: Super Contributor
timestamp: October 29, 2017, 09:39:06 pm
content: Ultrasonic welding and its cousin friction welding of plastics has been around since at least the mid-1970's. That is not new.Personally, i use a hot air welder for plastic. It is much like a hot air soldering. The major difference between plastic and steel welding is that you do not form a puddle and progress to form "stacked coins." You push the rod into the hot zone and apply heat to the rod until it fuses.

author: rrinker
author_rank: Super Contributor
timestamp: November 01, 2017, 02:59:24 pm
content: Mid 70's, plastic friction welding was a TOY - I watched that video a while ago, not sure if Fran mentioned it, but I think I did comment on her YouTube page about this - I had a toy called the Mattel SpinWelder - a little handheld thing with a 6V motor that ran off a lantern battery. Plastic trigger switch with simple contacts, and they supplied the 'welding rods' with little cups molded in to the drive end that you press-fit to the motor shaft. The various kits (I had one that build a Can-Am race car) has various beams and rods you welded together to form the framework, and there ere also, in the case of my car, body panels you welded to the frame. The rear wheels of the car had metal inserts for a flywheel effect, and there was a tri-star shaped tip that could attach to the motor and mated with the wheel hub to spin it up and then you could let it zip across the floor. Inevitably crashing into something and breaking piece off, requiring more welding. Since it ran on a 6V lantern battery, I built most of mine while camping.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 01, 2017, 03:29:11 pm
content: In the US, Harbor Freight sells a kit of about 30 rods of several materials. They originally come from China so I would assume that similar kits are available worldwide from a variety of vendors.A little experience and practice makes it pretty easy to pick an appropriate material for the job at hand. All of the usual subjects for heat generation work pretty well - friction, resistance heating, hot air etc. If you are using a soldering iron be sure to dedicate a tip to the job. The plastic really messes up a tip.All of the issues with metal welding also apply. Depth of weld, size of heat affected zone, voids, slag inclusion. So while it is pretty easy to do a so-so job it takes time, practice and care to do a good job. The big difference is that the thermal conductivity of the various plastics is far lower than the metals, so heat application generally needs to be far slower and it takes far longer for the joint to "set".

author: Old Don
author_rank: Regular Contributor
timestamp: November 06, 2017, 04:38:36 pm
content: Use of plastic welding rods is something that I never saw used on a production floor of any plastics plant I ever visited and I visited plants all across the country. Way to slow, but I guess if it works, it works. There's some videos on youtube where they use a hot air gun to weld and I guess for thick plastic that would be interesting to try.Ultrasonic plastic friction welding is a standard process used by makers of plastic products. That's used to weld a great many products. Hurts the ears standing next to the operator unless you have muffs, but works great.I've also used MEK, methyl ethyl ketone, to melt plastic pieces together, works great on some (PS, ABS) but not all plastics. Polyethylene and polypropylene resists welding with MEK. More or less what clear liquid plastic hobby cement or glue used to be and it was more common back before all the health rules and MEK is toxic, flammable and is not something to use in a closed room or near flames! You should read and understand any warnings on the can or bottle!You can make a hot wire welder for polyethylene and polypropylene bags and such.

author: jpanhalt
author_rank: Super Contributor
timestamp: November 06, 2017, 05:29:18 pm
content: I disagree that plastic welding with filler rods is not used commercially. Here's a company that explains how it welds plastic tanks:http://kchservices.com/products/process-tanks/polypropylene-tanks?gclid=EAIaIQobChMI0-SN9rqq1wIVxiSBCh0jNgGpEAAYAiAAEgJlkvD_BwEEven large ag tanks, which may not be totally welded will have welded parts, such as the tops.As for solvent welding, that can be tricky. Many plastics, most notably in my experience acrylics, will show crazing after solvent welding. Sometimes, that is not evident until years later. Polystyrene is also susceptible, but less so depending on the solvent used.

author: tooki
author_rank: Super Contributor
timestamp: November 06, 2017, 10:30:36 pm
content: Quote from: rrinker on November 01, 2017, 02:59:24 pmYou mean the Spin Welder she's holding in the poster frame of the video in the original post?Yes, I think she's mentioned it.

author: helius
author_rank: Super Contributor
timestamp: November 06, 2017, 10:38:22 pm
content: Hot air welding is a very common process, especially for butted roofs and other watertight plastic assemblies. It uses a y-shaped head that draws the filler rod into the gap and presses the sides together. Leister is the big name in that space.