Square sonotrode

Hi Sohkl, welcome to the board.

[quote]I have an square sonotrode that was crack at the center. Is it possible to get it repaired?[/quote]
No, once it's cracked you're left with an expensive paperweight...

[quote]can I just copy the shape?[/quote]
As long as it's a fairly simple shape with no dimensions greater than about 3/4 of its length, you can probably get away with this. If you use a high-strength aluminium or titanium alloy (whichever the original was made from) you'll probably get somewhere near the same sound velocity, which determines the dimensions.

But even then you'll probably still need to go through a tuning process - make the horn a few mm longer than the original and gradually machine down the length to achieve the correct resonant frequency. Unfortunately this really needs a specialised horn-analyser.

I doubt if you'd damage the Branson generator by testing it with an untuned horn (it ought to protect itself) but you might well get no information from it about how to tune the horn. (Disclaimer: if you do want to fit the expensive Branson generator with an untested horn then you do so entirely at your own risk!).

Because of the difficulty tuning you might consider asking a specialist to manufacture the new horn for you - most people will work from drawings or old parts to make replacements.

[quote] Where can I get used US gen at 30kHz?[/quote]
Well strange as it seems I've heard of used ultrasonic equipment being sold on Ebay... Otherwise a google search for [url=http://www.google.com/search?q=used+ultrasonic+plastic+welding+equipment... ultrasonic plastic welding equipment[/url] turns up a few possibilities. [url]www.bymultrasonics.com[/url] looks like a possibility (I don't know them - just that their site came up first in that search).

Hope that helps and good luck with your project...

Chris