Wire breaking in Intermediate wire drawing

In our intermediate wire drawing machine, we are getting less diameter at different lengths. However, after pressing emergency stop on the machine at specified speed (Production speed), the diameter is coming perfect.

We tried different dies but still the problem is same. Also the machine parts pulleys, annealer band have been checked and it is ok.

I don’t know why the wire diameter is coming less at different lengths.

Please provide your suggestions.

Hi there,

Well I think you have pretty well answered your own question.

Assuming that the machine is wired correctly, the annealing electrical power is instantly off just as soon as the emergency stop button is pushed. Thus, as the machine slows down, hard wire is produced. Since the wire in on size after the emergency stop button is pushed, it is reasonable to conclude that the drawing machine and the finish drawing die are not the problem.

Instead it is downstream of the finish die and I suspect that the wire is being stretched for one or more reasons. Make sure by micrometer measurement that all annealer capstan diameters are correct including the dry capstan on the drawing machine. Then make sure that all idler pulleys (non-driven) on the annealer rotate free and easy. You can actually feel a damaged or sticky bearing. Slowly rotate every one of these pulleys carefully by hand a number of times and feel for damaged bearings. Repeat this procedure for all the non-driven pulleys in the speed control dancer/ accumulator in front of the take up.

Now comes the timing of the annealer. You must follow the annealer manufacturer's instructions to the letter but you need a proper instrument to accurately measure the rotational speed of the pulleys and the dry capstan. I recommend the following contact instrument from Schmidt Control Instruments and make a number of measurements so you are absolutely sure of your numbers:

www.hans-schmidt.com/EN/products/tachome...series/model_dt-105a

Non-contact instruments are in my experience just not sufficiently accurate for annealer adjustments.

Best regards,
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com

Hello,
Isolate the problem; is it in the annealer or wire drawer. Most machines allow you to by pass the annealer and run hard wire. If the hard wire has good diameter measurements, string annealer up and try again. If diameters are bad then problem is in annealer. At this point in time you need to follow Peter's advice.

Hi everybody,
As mentioned, you are getting less diameter at different lengths. Lengths what you mentioned is reel length?
Then it looks like take up is pulling the wire as reel diameter builds up. You need to check dancer between annealer and take up. Check dancer pressure / dancer position from empty reel to full reel. (Practically dancer position should remain constant at all the time for any length on reel)

It would be nice if the original poster would update us. Question I have is: if I took a sample of wire and ran it through a laser micrometer or similar device would I find that the diameter is varying? How much is is varying. What size are you drawing. Is the variation within some spec? Is it fluctuating in and out of specs. You may be using the E-stop and the wire is good at that point but your E-stop is just that. It is an emergency device. You are not suppose to use it whenever you want to stop the machine. Depending upon the design, E-stops are designed to stop the machine as fast as possible and in the process it may be stressing the power train but that is OK in an emergency but not for general use. Emergency only.

the fact that the wire is ok at that time or point is not really relevant to you problem. What is it like further down the line?

I think that if your dies are right, and sized according to the design reduction of your machine, and the ratio between capstans, (and or individual capstan speeds) is correct then your problem is outside the wire drawer. That being the case you start where the wire leaves the final die and check everything from there to on the spool.