Fusing plastic pieces

This weekend I went to a LEGO exhibition with my daughter, and I gained a little nugget of information about how they fuse some of their parts together, which I thought I'd share, in case somebody finds it useful.

They use sound waves, more specifically at 20kHz, they didn't mention a specific amplitude, but the machine operators are required to wear hearing protection, so I guess it is pretty high.

The board said that at 20kHz the friction between the pieces would be sufficient to cause the blocks to fuse. The specific example was a LEGO window, where they used sound waves to fuse the transparent plastic with the frame.

... another idea: embedd some metallic wires in the gap to fuse and apply induction-heating, what's heating the wires and let the surrounding platic melt ...

---

Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

anton Wrote:
-------------------------------------------------------
> This weekend I went to a LEGO exhibition with my
> daughter, and I gained a little nugget of
> information about how they fuse some of their
> parts together, which I thought I'd share, in case
> somebody finds it useful.
>
> They use sound waves, more specifically at 20kHz,
> they didn't mention a specific amplitude, but the
> machine operators are required to wear hearing
> protection, so I guess it is pretty high.
>
> The board said that at 20kHz the friction between
> the pieces would be sufficient to cause the blocks
> to fuse. The specific example was a LEGO window,
> where they used sound waves to fuse the
> transparent plastic with the frame.

Nice! Thank you ;-) -- This is interesting, I am sure we can use this info later.

---

---
New cutting edge RepRap electronics, ARM 32 bits @ 100MHz runs RepRap @ 725mm/s:

[www.3dprinting-r2c2.com]

I made ABS paste by dissolving some scrap rafts in acetone. It doesn't cure quickly, but it makes a pure ABS bond.

I've been wondering if this can be used as an epoxy for joining the thermal barrier to the extruder block.

---

---

Darwin clone, Gen 2 electronics, Arduino Duemilanove w/ AtMega328, 5D Firmware, Pinchwheel extruder
[www.codeerrors.com]

It sounds like ultrasonic welding, with the right amplitude and frequency its possible to weld all sorts of materials, even wood.