Hello Mr. Chan,
First of all, I believe that this is a fine wire drawing and annealing process so stretching the wire at the annealer is of major importance.
You are correct in that the atmosphere in the annealing leg must not have any oxygen in it and this is accomplished in your case by providing a saturated or dry steam environment. In larger wire annealers, there is a cooling (water) leg (Immediately after the a water filled annealing leg. The annealing leg is where wire heat provides a protective steam envelope.) to ensure the wire is properly cooled before being exposed to oxygen. Because of this, the wire leaves the annealer somewhat damp and a supply of clean and dried compressed air which dries the wire. This may be one or two air wipes.
In your case however, I expect the heat sink in the wire is quite small and thus the cooling section of the annealer can supplied with steam so that the wire can properly cool down to the point where oxidation cannot occur.
There are only two places where grunge can get into the annealer.
i) Contamination on the wire.
ii) Contamination in the saturated steam.
In a magnet wire plant, cleanliness is extremely important and I suggest that this extends to all the drawing lubricants.
a) Use water based lubricants mixed with deionized water with a normal pH for your area. (See below)(Change all your tanks and start anew.)
b) Use clean deionized water in your steam generators. Clean all annealers first and then start anew.
c) Clean out all annealers and set up a regular schedule to clean these annealers. Monitor your drawing lubricants.
To answer your questions:
1. The annealer tube should be damp but the wire must exit the annealer clean and dry.
2 Your steam generator may need cleaning.
3) See item b above.
4) See all items above and regularly check your wire for contamination by passing the copper wire over a clean, non-linting, fine weave, white cotton cloth. Do this on a regular basis so you will have some idea when the drawing lubricants need recharging.
We obtained this advice from Spectre07 years ago and it is still very appropriate today. Log the properties for each lubricant emulsion on a regular basis and thereby take control of the situation.
"In most cases, an initial pH of 8.0 to 9.5 (alkaline) is satisfactory but the actual point for each wire mill and lubricant must be determined on the basis of experience. The pH will drop as time goes by for various reasons."
Spectre07 previously provided us with some quick and practical tests for determining the effectiveness of your wire drawing emulsions.
"How good is my drawing emulsion?
pH
"Years ago I found a simple test that works fairly well for testing lubricants (emulsions). You can check the % fat and pH but sometimes these can look good and you still have a problem. Take a sample and measure the pH. Take a shiny stainless steel rod 3/8 to 1/2" in diameter and about 10 " long. Stick it into the sample, then pull it out and hold it nearly horizontal with the end pointing down about 5 degrees from horizontal. Observe what happens to the lubricant (emulsion) that was on the rod when you removed it from the sample. If it tends to slowly roll down to the end of the rod then it probably is coating your capstans equally well. Increase the pH a couple of tenths. Stir and then check lubricant with the rod again. As long as the lubricant tends to roll toward the end of the rod, the surface tension is good. Once you reach a pH that results in the lubricant opening up bare spots on the rod instead of rolling to the end means that the surface tension is not good. It will be the same on your capstans. Reduce the pH some Until the lubricant (emulsion) rolls off again."
Lubricity
"Another test is feel - dip your fingers in the lubricant (emulsion) and then rub your wet fingers together - do they feel slick? If not then the lubricant (emulsion) is not slick."
Detergency
"Another test is take your dirty hands and dip them into the lubricant - do your hands wash clean?
If not then you need to put some fresh lubricant (compound) into the tank. Some people think that they are saving money by not "using" lubricant (compound)" however I believe that the essential elements in the lubricant (emulsion) breaks down - and adding fresh lubricant (compound) restores those essential elements."
Thank you once again Spectre07
Regards
Peter J. Stewart-Hay
Principal
Stewart-Hay Associates
www.Stewart-Hay.com
519 641- 3212