newb-copper rod breakdown

I am new at copper rod breakdown , we breakdown 5/8 inch rod to 12-14 awg with a fragico zero slip rod machine. We 'recently' have ALOT of wipeouts at the 4th and 5th blocks with welds.
1- The hot welders have been working perfect for years.

2- We do not use the first block for maintenance reasons.

Just want to know the 'possibilities' of what could be wrong. You know more than I do now , if you need more info, I will do the best to get it.

- please don't flame me for not knowing anything -

Hi there,

First please be assured that nobody is going to give you a hard time for not having all wire and cable process understanding and experience at your fingertips. Nobody knows everything about this business.

Secondly I am not personally familiar with the "Fragico" line of drawing machines but there is one Italian company called Mario Frigerio SpA or Frigerio SpA that builds zero slip drawing machines primarily for the steel wire industry. ( www.mflgroup.com/ ) The company advises that in "1998 Frigerio started a new venture with the formation of Frigeco, a new factory, dedicated to the processing of non-ferrous materials". Is this the company ( www.frigeco.com/index.htm ) you are referring to? To review the rod breakdown machines and their pictures, click on "Products" and then on Zero Slip and/ or Limited Slip. Is one of these the machine you have? Which one?

I have some questions as follows:


1) Are you certain that this is a zero slip machine? Zero slip machines have motors driving each individual capstan with some kind of capstan speed trim control from the wire entering each capstan. In other words, the capstans are not mechanically geared together.

2) What kind of drawing lubricant are you using. (Powder, grease, liquid?)

3) Are the capstans in good shape with no grooves or other damage (Especially the fourth and fifth capstans.) so that the wire can fleet (slide) across the surface of the capstan properly? If you have a "Mod. TA" drawing machine, there is a second idler capstan, offset to space the wires on the driven capstan and to elimate the fleeting process on that capstan.

4) What is the drawing progression you are using? (AWG?)

5) Are you using carbide dies, polycrystalline dies or a combination of both? If both, at what size does it change over to polycrystalline dies? (Like say at the die immediately preceeding the sixth capstan.)

6) Are the die sets kept in strings and changed as full sets?


As far as hot rod/wire welders go, every machine can use an overhaul once in a while. In hot welders, springs can weaken over time and copper oxide can be left in the weld instead of being forced out (The flash ring around the weld.). Likewise, welding spall or spatter can gum up the jaws and impair the proper operation of the machine. It also should be a multiple upset machine meaning that once the weld is made the rod is forced together a second time (Giving a larger flash ring.) to completely remove the initial weld impurities. In other words, the age and historical performance of the welder is no guarantee that it has not begun to malfunction.


7) Is the hot welder in really good shape and when was the last time it was really overhauled (Preferably by the manufacturer.)?


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

vettecoupe-

i checked out www.frigeco.com/inglese/presentazione_inglese.htm and yes , it is THE same exact one. It is zero slip, every cap is driven by an individual motor, and they all have speed controllers

2- drawing lubricant - liquid , i will have to get back to you.

3- caps are in good condition , there is a second idler pulley , some caps , the wire is alot looser than others , could this be a problem? I noticed on their site they say up to 8 wraps , we use 8-9-10 + wraps , could this be a problem?

4- we run about 50% first die , 40% second die , then 28-36% the rest , I could get back to you for the exact percentile.

5- The dies , I would get back to you , I do not Know , they are new though , 3 new sets in three years.

6- The hot welder - We brought it back to other rod machines and they worked perfect, we have a brand new welder and it always breaks at the 1st,2nd,3rd block. Maybe because its from overseas and has different voltage,amps, hertz , etc. , but with the welds- we could go days without a break then hardly make a pound for a week.

7- welder is actually in great condition, overhaul , no , the usual pm . Manufacturer - no - it is our hack job. I could probally see 1% from the manufacturer. oh - i dont understand the multiple upset machine part , this welder just welds the rod in one straight shot , any more info would be great,Thanks !!

Hello again,

OK we can forget about items 1 and 2 and most of item 3 now.

As far as your question in Item 3 goes, as long as the wire is not slipping on the driven capstan, the observed looseness does not matter.

The reason the wire breaks early on (At the first, second or third die.) is because that is where you take the largest draws and you must always keep in mind that a drawing machine is a sort of "quality control device", continuously "measuring" the quality of the material entering the machine.

The reason the welder seems OK at other drawing machines is because I expect they employ AWG drawing progressions and that means the area at each die is reduced by 20.7%. That is a lot less than you are doing on your non-slip machine, especially at the first three dies. This means that your welds do not have to be quite as perfect on other machines as they need to be on the non-slip machine. (Although the intermediate wire may break as a result of rod welding flaws when it is redrawn. This is akin to a wire break from say a magnetic inclusion in an intermediate (slip type) drawing machine at 26 AWG. The inclusion made it through the rod breakdown (slip type) machine and mostly through this second drawing operation.) Thus a comparison with a slip type machine really doesn't count, it just confuses the issue.

At your zero slip machine, you require a perfect weld each and every time and thus a very high quality rod welder is necessary.

As far as the intermittent welding problem goes, if you believe your welder is in perfect electrical and mechanical condition, then it comes down to some other variable like the way the ends are prepared before welding.


- Always cut back say four inches before preparing the ends.
- Ensure that the ends are square and properly filed smooth.
- Ensure that the rod ends are properly aligned in the welder (Not offset.)


After welding:


- File off the ring burr properly so that the rod surface is smooth and shiny.
- Ensure there is no damage to the rod surface(gouges, etc.) from the jaws.
- It is also important change the file regularly so that broken file teeth do not get embedded in the copper.


As far as multiple upsets go, think of it this way:


a) - The rod ends are prepared properly.
b) - Hot welding is done as you are doing it now.
c) - While the rod is still hot (or perhaps reheated) between the jaws, the jaws reset, grab the rod again and push the just welded rod ends together some more.
d) - This pushes out more hot copper at the weld point and thus eliminates the possibility of copper oxide from the hot welding process (or other defects) still remaining inside the just welded rod.


August Strecker GmbH & Co. KG (Limburg, Germany) ( www.strecker-limburg.de/ ) manufactures and sells multiple upset hot welders for 5/8 inch copper rod. (Machine Type MS80.)

The T. Fukase and Company Limited (Tokyo, Japan) ( www.fukase.co.jp/ ) markets the Hakusan heat pressure welding machine which it states are the " the most reliable welding machines for wire drawing industries. It performs no-wire breakage during wire drawing process." I expect this statement however was based on experience with the standard AWG drawing progression. ( www.fukase.co.jp/HeatP.htm ) You would need a BFH series machine.

Perhaps you can get one or both of these welders in on a trial basis. The welder's electrical requirement should of course be fully compatible with your electrical service. You would also have to tell them of the way you are drawing the rod with the area reductions at each die documented.

This then clears all of the previous points and I think this is all the information you need.

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

vettecoupe -

Thank you for the outstanding information! I will take it into practice and follow up on other welders. Thanks again!