A common technique to successfully 3D print complex objects is to print separate pieces and then glue them together. But are there other techniques for joining pieces together? Apparently yes.
There is a technique known as “friction welding”, which uses the principle of friction-generated heat. If there is sufficient friction, the heat may be high enough to melt or soften 3D prints made of ABS and particularly of PLA as they have a lower melt temperature.
In this video friction welding is demonstrated. The approach is to insert a filament segment into a Dremel or similar tool and spin it at very high speed. The tip of the rotating filament touches the print and friction generates heat. Some of the filament’s melted plastic is deposited on the print if you handle it carefully. You can also drill smooth holes in the print by simply pushing the filament through.
Is this approach useful for joining two pieces together? Maybe, but it would require a lot of very careful work to do so. Probably it’s less effective for joining pieces than it is for welding holes closed and other small repairs.
But it’s yet another approach to put in your 3D printing toolkit.