Drawability of copper

What should be the maximum number of wire breaks in a multi, fine wire drawing machine with copper wire in a range from 0.5 mm (0.01968 inches or about 24 gage) to 0.1 mm (0.003937 inches or about 38 AWG)?

Thanks & Best Regards,

Hello there,

I'm going to get you to answer your own question as follows:

A) If everything were perfect in terms of drawing lubricant, capstans and annealer timing, annealer contact rings, and so on how many wire breaks would you expect per week with a single, fine wire drawing machine using your standard copper supply?

If we assume you evaluate all wire breaks on this single wire machine, how many were due to metallurgical problems? (Oxides, seams inclusions and so on.) and how many were introduced during the previous wire drawing operations?

C) Now if you were using the highest quality copper such as Upcast oxygen free that was drawn properly in preceding operations and thus all theoretical problems introduced at those previous drawing operations were eliminated, how many wire breaks would you expect to have per week on this single wire machine?

D) Now, if you take that number from (C) and multiply by the number of ends you are drawing, that is the number of wire breaks a week you should be striving for with a vengeance.

Nothing short of perfection is required if you want high outputs and that includes constant monitoring and control.

Sincerely,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Peter,

One variable that was not mentioned is wire drawing speed and of course the type of equipment. There are lots of old type machines that with half decent or above average mechanical parts, a good lubricant, the right dies, good copper, etc., and running about 300 to 500 meters/minute would run forever and almost never have a wire break.

You've given some ways to check on break frequency but it would be nice to know if he has a problem or only thinks he has a problem.

spectre

Install new equipment, 3X or 4X the speed and wire breaks escalate and the only thing that has changed is the operating speed.

Hi spectre,

You are right again of course. Good to have you here to keep me honest. In my mind's eye I saw all the machines as high speed and compared at the same speed but I never wrote it down. I still think a way faster than I type. Thank you for catching it. I am getting old! I will be 65 this May.

Sincerely,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

hi there,
I agree with all these points, but is there any standard data,assuming all the conditions stable, about number of breaks /kg of wire drawn for smaller sizes? especally in multi wire machines drawing upto 0.1mm @ 20-30mps?

Thanks & Best Regards,

Hello again,

I personally have never seen a published set of standards because of all the variables as previously described. Each company therefore sets its own statistical standards and continually strives to maintain or improve upon those standards. I imagine that each manufacturer considers this proprietary information and thus I expect they are not likely to share the information with other wire and cable manufacturers.

If you are not already using SPC to control this, I suggest you read the 1990, 176 page paperback titled the Practical Application of SPC in the Wire and Cable Industry by Douglas B. Relyea. I note that there are 6 used copies for sale at Amazon.com so if you want one, you had better order it fast.

www.amazon.com/Practical-Application-Wir...id=1203864518&sr=1-1

The book is out of print but if you search the title with "Google", I'm sure you will find other sellers around the World.

Once that is working well (capable and stable), Six Sigma is then just one more step. You can read the basics on our web site at www.stewart-hay.com/process2ie.htm

Sincerely,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com