Ultrasonic Welding...hmmm

[jaxvon]

Being the internet addict that I am, I did some more surfing and found some interesting pro cables at ProCo. They seem to be the normal, high-quality company, save one difference: ultrasonic welding.

I sent an EMail to their head of engineering inquiring about this process, and this is what I got back:

Hi Jackson,

Ultrasonic welding is a type of pressure welding that bonds together two
separate parts using high frequency mechanical vibrations and pressure. It
provides a better electrical connection than either crimping, soldering,
IDC, or conventional welding. It is stronger, more reliable, and has no
intermediate layer as do some other connection techniques. The fusing
together of the two materials by using ultrasonic welding is by far the best
electrical connection I have ever seen or heard of, period. It is used
extensively by many speaker manufacturers for attaching the voice coil wires
to their terminals. And the automotive industry uses it for a variety of
connections for it's superior mechanical strength, resistance to vibrational
failure, and ultra reliable low resistance connection.

No marketing, no hype, just God's truth and science,
Hope This was of some help,
Gerald Carpenter
Pro Co Engineering

This sounds like a pretty sound idea to me (pun intended). I assume that the only reason that other manufacturers don't use this technique (if it is as good as he claims) is simply because of cost. Anyone have any thoughts on this stuff?

And to the moderators, PM if you think I'm being a post whore and that I should lay off.


Jackson

 

[Rip Van Woofer]

I strongly doubt that any welding/soldering technique has any significant electrical or audible effect on audio cable since the only things that matter in audio cables are resistance, capacitance, and inductance. Physically stronger and more reliable? Maybe. But I'm no metallurgist or even a certified welder.

And if you're a post whore with only forty odd posts, geez, what does that make ME??

 

[jaxvon]

Yeah. I read Jim Dunlavy's series of posts a few days ago and he proved that soldering, even the "worst" of connection techniques, does not make anywhere close to an audible difference. The only advantage I could see is a more secure connection that won't come loose after handling and vibration.

 

[mtrycrafts]

Yeah. I read Jim Dunlavy's series of posts a few days ago and he proved that soldering, even the "worst" of connection techniques, does not make anywhere close to an audible difference. The only advantage I could see is a more secure connection that won't come loose after handling and vibration.

John Dunlavy

Here is a link to an article, or do a google search where this came from on page 5 or 6

http://www.azom.com/details.asp?ArticleID=119

I seriously doubt normal instruments can measure the resistance difference between this method of welding and soldering or maybe not even that national standards lab.

And if you don't play with the wires, I don't see a worry about durability.

 

[Mr.T]

I certainly can appreciate good soldering connections in any type of circuits including printed circuit boards.
In my opinion poor soldering connections should not effect the low spectrum audio frequencies between the range of 50HZ to 10KHZ used in sound systems. But I certainly know that poor soldering connections will effect the inductance and the operation and performance of high frequency circuitry like RF circuits with VHF and UHF frequencies found in Television tuners and ultra high frequency transmitters.

Quite a few years back, I had the opportunity to get a job with a company called "Singer Kearfott" a manufacturer of navigation systems for military airplaines. I ended up to work in Plant 1 which was and still is located in the same place

Plant 1 was handling mostly "GYROS' which was part of the complete navigation system and the copper wire used in this type of equipment harnesses had to be freshly made before installation to make sure that it will meet the rigorous tests of impedence that was required by the company.

A huge amount of this wire was tossed in the carbage every month, if didn't meet their specifications, that's how stringent was the quality control applied to this type of equipment, because most of these apparatus dealt with super high radio frequencies and even a 10% of oxidation on the wire was not exceptable.

So going back to audio frequencies equipment, in my opinion are much easier to handle and manufacure.

Mr.T

 

[markw]

Solder should never be depended upon for a physical or electrical connection. The two items being joined should already have a tight mechanical bond before the solder is applied. All the solder is intended to do is to a) reinforce the physical connections and B) provide an oxygen free environment for it.

 

[Mudcat]

Ultrasonic welding is a type of pressure welding that bonds together two separate parts using high frequency mechanical vibrations and pressure.


This is a true and correct statement.

But!

It does not mention the type of ultrasonic welding. Most ultrasonic welding is performed at 10 to 40 kHz. This type is universally reserved for thermoplastics, and is cost competitive with other soldering,brazing, glueing, welding techniques. It is not compatible with metals. Softer plastics would be welded at the lower frequencies, and harder acrylic type plastics at the higher frequencies.

To use ultrasonic welding on metals, the frequency needs to be in the 60 kHz plus range. This type is used in the semiconductor industry and is very expensive. So expensive that I sincerely doubt that a budget cable companty like ProCo will be using it for audio cables.

 

[Swerd]

I am not a metalurgist, but here is what I could gather from this article http://www.amtechultrasonic.com/articles/theory/theoryarticle.shtml

Compared to fusion or spot welding, ultrasonic welding of metals is a fast, reproduceable, low temperature method that works well when bonding non-ferrous metals, such as aluminum to copper (as in speaker voice coil leads). It is especially good when metal surfaces are oxidized (see page 4). So it may be useful for terminating copper wires.

From page 5:

"Fusion welding creates a nonconducting, brittle, intermetallic compound that reduces the ductility of the copper/aluminum bond. As the molten metals mix and approach an alloy of 12% copper an alloy is formed that is too brittle for most applications. Since the ultrasonic welding process does not cause melting, these intermetallics and brittle alloys are not formed when joining these materials.

The metallurgical makeup of copper wire used in the manufacture of electrical harnesses is a very difficult one to spot weld due to the presence of electrolytic tough pitch copper often present in the wires. When heated in a reducing atmosphere, the oxygen present in the copper may cause embrittlement and therefore threaten the integrity of the connection. Furthermore, the copper wire used in wire harnesses is very conductive and extraordinarily high electrical currents are needed to generate sufficient heat in the wire to effect a melt. Oxides and contaminants on the wires as well as electrode wear will drastically change the resistance of the assembly and the amount of heat produced. When too much heat is generated during a resistance weld cycle, the assembly can be damaged, making it possible for an extreme variation from part to part depending on the amount of oxides or contaminants that were present on the wires before welding."​

Page 8 lists some of the present industrial applications.

 

[Swerd]

Why should heat be avoided when making a wire termination? When soldering on a terminal, heat can create conditions that lead to a brittle connection. See section 3.1 in this article: http://www.audioholics.com/techtips/audioprinciples/interconnects/componentvideocables3.php

In my above post, I assumed that a high-temperature weld could lead to the same brittle joint that has been observed with solder joints. I don't want to make too big a deal over this, but ultrasonic welding might avoid brittle joints. I don't believe there would be any audible superiority to such a joining method, but it could produce a joint that is less brittle and lasts longer. There are other ways to accomplish this. The above audioholics article explains how the use of oxygen-free copper instead of electrolytic tough-pitch copper in soldered joints also leads to less brittle joints.