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"Finishing Technology Hotline BBS" Postings by Topic

Ed. note: before the internet existed, there was a time when "Sysops" (system operators) ran publics forums via dial-up modems and "BBS" (Bulletin Board System) software. Here is one such discussion from 1993.


Engineering for Plating



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Msg. #3987 in ** Ask Plater B**
Posted on 08/03/93 at 08:06:54
To: ALL From: TED MOONEY - Insufficient voltage again? We are trying to nickel plate very large steel sheets at 50 ASF. THe rectifiers are 12 volt units and we cannot get above 25 ASF with our 23 inch anode to cathode spacing. Even when we get the spacing down to 9 inch we can only get to 40 ASF. It's a typical watts nickel, 140 degrees F., titanium baskets. We had a lab measure solution conductivity and it seems to be on target. Sheesh--Is it really going to require 24 volts to nickel plate?

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Msg. #3988 in ** Ask Plater B**
Posted on 08/04/93 at 19:53:36
To: TED MOONEY From: BERL STEIN - Reply To 'Insufficient voltage again?'
Ted, there are several things you can do to lower the required voltage, but bringing the work closer to the anodes is certainly highly desirable
- otherwise you'll be heating your electrolyte more than doing electrodeposition. With flat pieces and anode baskets the normal anode -to-cathode distance with rack plating is 2-6 in. Now to the business of lowering the required voltage. Anodes
- use sulfur depolarized rather than electrolytic Ni, the former ones corrode at a much lower voltage. Chlorides
- make sure you have a high enough concentration to promote anode corrosion (you can use up to 60 g/l as NiCl2 safely without affecting the Ti). Check how much voltage is lost in bus bars and (often overlooked), if the Ti anode baskets have Cu or brass hooks (coated, naturally) to improve the current carrying capacity. And, finally, is your Ni concentration sufficient to lower the cathodic overpotential? Good luck, Plater B

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Msg. #3993 in ** Ask Plater B**
Posted on 08/15/93 at 08:26:15
To: ALL From: TED MOONEY - High Voltage IS required for nickel. We're starting up a big nickel plating line, and with 23 inch anode to cathode centers, the 12 volt rectifiers couldn't bring us anywhere near the desired 50 ASF. We have been hunting high and low for what is "wrong" with the solution, bus bars, anode baskets, etc. Here's the answer: there is nothing wrong! 12 volts is just not enough, and neither is 18. 24 volts may just be enough, but probably not quite. That's the sad truth, so now see if you can figure out why! The tanks are 18 foot wide, 14 foot deep, 64" D.O.T. The work to be plated is sheets of steel or stainless, up to 13 foot wide by 10 foot deep. The solution is a low pH, brightener-free, watts nickel with enough chloride, and sulfurized anode crowns, operated at 140 F. This is NOT a trick question, and I've given you all the important facts. But there is something VERY different in that description from most of the installations you have seen. Grab your textbooks, then explain it. Answers next time.

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Msg. #3994 in ** Ask Plater B**
Posted on 08/16/93 at 20:20:21
To: TED MOONEY From: BERL STEIN - Reply To 'High Voltage IS required for nickel.'
How about agitation
- is it strong, poor or non-existent? Why does the anode-to cathode distance have to be that high? Are the sheets you are plating thick enough to carry the current you need without a substantial voltage drop? Any one of these factors might cause you a problem. So can a low anode-to-cathode surface area too. But tell us what it really is, Ted. I, for one, am dying to learn the answer. Cheers, Plater B

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Msg. #3997 in ** Ask Plater B**
Posted on 08/16/93 at 22:58:12
To: BERL STEIN From: TED MOONEY - Reply To 'High Voltage IS required for nickel.'
The air agitation is sufficiently strong, with a pretty normal rolling boil. The contact lugs and the plates themselves are plenty sufficient to carry the current. The anode-to-cathode spacing does have to be approximately that high, unfortunately. Some feel the anode area is insufficient--and it may indeed be a little skimpy when plating the largest sheets, but it's not really the problem. The problem is that there is no problem--except the huge cost of 24 volt rectifiers, cooling coils to remove the horrendous rectifier load, and moving the anodes in a couple of inches so 24 volts will be enough. But I was sure 12 volts would be enough, and so was everybody else I talked with over the course of the project. It WASN'T EVEN HALF ENOUGH! Now I know, and now you know, and now everybody else knows. But I am convinced that I know why this result disagrees with all my prior experience, and am just seeing if it runs counter to everybody else's intuition as well--and if somebody else would have been smarter than me in having seen a problem brewing.

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Msg. #4008 in ** Ask Plater B**
Posted on 08/17/93 at 17:38:24
To: TED MOONEY From: BERL STEIN - Reply To 'High Voltage IS required for nickel.'
Umh...

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Msg. #4017 in ** Ask Plater B**
Posted on 08/18/93 at 16:23:12
To: BERL STEIN From: TED MOONEY - Reply To 'High Voltage IS required for nickel.'
Berl, I sent you E-mail with what I think is the explanation. Don't want to spoil it if somebody else wants to give it a shot. /s

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Msg. #4036 in ** Ask Plater B**
Posted on 08/25/93 at 23:31:48
To: TED MOONEY From: VALENTINUS BRINKMANN - Reply To 'Insufficient voltage again?'
what's the current capacity of the rectifier?

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Msg. #4040 in ** Ask Plater B**
Posted on 08/26/93 at 00:55:54
To: VALENTINUS BRINKMANN From: TED MOONEY - Reply To 'Insufficient voltage again?' 16,000 Amps. But we can draw nowhere near that at 12 volts, Val.

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Msg. #4057 in ** Ask Plater B**
Posted on 09/01/93 at 22:25:24
To: TED MOONEY From: VALENTINUS BRINKMANN - Reply To 'High Voltage IS required for nickel.'
As far as the cost of 24v units goes, you can hook 2 12v units in series with no ill effects. depending on the units, there may be some control reworking but it's minimal. What type of steel were you working with? and what condition was it in?

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Msg. #4059 in ** Ask Plater B**
Posted on 09/01/93 at 22:46:20
To: VALENTINUS BRINKMANN From: TED MOONEY - Reply To 'High Voltage IS required for nickel.'
Yes, we can hook 2 rectifiers in series but they're $30,000+ critters for 12 volts and $42,000 for 24 volts. It's an expensive problem. The steel is plain H.R.S., or various grades of stainless, properly cleaned and conditioned. The condition of the substrate is not the problem. The problem is the assumption that 12 volts sounds right when, in fact 24 isn't quite enough. Again, I now know what is "wrong" (but 'different'
would be a better word than 'wrong'). Here's another hint: have you ever seen those demonstrations of magnetism where they put the ends of a horseshoe magnet under a piece of paper, then sprinkle iron filings on the paper so you can "see" the magnetic flux lines?

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Msg. #4193 in ** Ask Plater B**
Posted on 10/14/93 at 22:45:11
To: ALL From: KEN ROSENBLUM - shop questions Does anyone have any opinions on the following equipment options? 1) Tap switch vs SCR rectifiers for industrial zinc and nickel plating. I think that tap switch rectifiers are much lower maintenance, but you get better control with SCR controls. 2) Gas vs. Electric ovens for baking zinc plated parts that will be chromated after baking. Electric ovens are much more expensive to operate, but I have heard that sometimes gas fired ovens leave a film on parts that is difficult to remove before chromating. Anyone with first hand experience? 3) Steam vs hot water boilers. We currently use steam, but are looking at a new boiler (~150 HP). I have heard that hot water boilers offer lower maintenance costs, but require much larger heat coils. DOes anyone know of industrial plating shops (zinc, nickel, etc) using hot water boilers? Are they satisfied with them? Do they have to live with longer heat up times? Would they be feasible to heat electroless nickel tanks (190F)? 4) We currently zinc and yellow chromate parts. We spend a lot of time blowing the water bead off parts before going into a forced air dryer. If we don't blow off this water bead, the yellow chromate will leach out before the parts dry. I would like to eliminate the labor of all this blowing. Do dryers exist to accomplish this? Are they worth the cost if they do? I have been in a number of other plating shops and they all seem to do as we do. I know this is a long letter, but thanks in advance if anyone has experience with these equipment options.

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Msg. #4194 in ** Ask Plater B**
Posted on 10/15/93 at 03:14:26
To: KEN ROSENBLUM From: TED MOONEY - Reply To 'shop questions' 1) SCR rectifiers also offer remote control and faster, easier, setting than adjusting the tap switches; plus you can use current control or current density control in addition to voltage control. Both are used extensively in actual practice, but my experience is tap switches are usually used for cleaning and SCRs for plating.

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Msg. #4195 in ** Ask Plater B**
Posted on 10/15/93 at 03:24:09
To: KEN ROSENBLUM From: TED MOONEY - Reply To 'shop questions -- hot water boilers.' 3) I know of only one hot water boiler in use: Mid Atlantic Finishing, Capital Heights, MD 301/322-2233. Our AESF Nat'l President, B.J. Mason, can give his opinion. Neither he nor I particularly wanted it, but the gen'l contractor who built his plant for the Philadelphia city hall tower plating project picked water over steam. The disadvantage is not only larger coils, but you need high flow rates and this was only accomplished with high water pressure (90 psi), which we found a bit scary in open top tanks. I wanted to hate the hot water boilers, but frankly they result in quiet, low maintenance operation. They're actually not a bad idea at all if most of your heating can go through steel coils (soak clean, electro clean, etc.). If most of your heat needs exotic coil materials like titanium or tantalum or teflon, the much larger coil sizes will be prohibitive. M-A-F has electroless nickel tanks but I can't remember whether they also use the hot water, since they were not part of the project I worked on. B.J. Mason can tell you though. /

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Msg. #4196 in ** Ask Plater B**
Posted on 10/15/93 at 03:31:15
To: KEN ROSENBLUM From: TED MOONEY - Reply To 'shop questions -- Blow off and drying' 4) I think the best answer for you, if otherwise practical, might be an efficient rack dryer built into the line. Use a low temperature (140) but a lot of air (really FORCED). I have many customers who do this. I won't say they never have any leaching problems at all, but the approach is clearly working for them on a production basis. THe trick is, as you imply, plenty of air movement. Also, keep the final rinse only warm, not hot, and the immersion short. Reasonably thin stampings and so on will come up to tank temperature in well under a half minute, so long immersions aren't necessary.

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Msg. #4219 in ** Ask Plater B**
Posted on 10/24/93 at 22:32:57
To: BERL STEIN From: KEN ROSENBLUM - Spin Dryers Berl, In follow up to my last message about the bathing suit spin dryer, If you're interested, call me at (612) 645-0787. I'll give you the name of the health club and they can tell you who manufacturers and distributes it. Ken

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Msg. #4224 in ** Ask Plater B**
Posted on 10/25/93 at 15:22:10
To: KEN ROSENBLUM From: BERL STEIN - Reply To 'Spin Dryers'
Thanks, Ken Berl

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Msg. #4225 in ** Ask Plater B**
Posted on 10/25/93 at 21:56:41
To: KEN ROSENBLUM From: VALENTINUS BRINKMANN - Reply To 'shop questions' 1. SCR rectifiers DO give much greater control, offering current limiting, and voltage limiting as Ted pointed out. The newer models also offer voltage and current ramping at a predetermined rate of gain. This has excellent results especially in anodizing to avoid "burning". They also offer the possibility of remote monitoring and controlling, manually or by PLC. I've found them to be very reliable. The only reason I'd buy a tap switch model these days would be because of a really great price and an application that really didn't require a lot of variation or tight control. 2. We have a customer with a large job-shop who just changed over (3) large ovens from electric to gas,And another who converted two large dring rooms from elec. to gas. Neither one has suffered any ill effects from the switch. 4. In addition to what Ted said, we had a customer with the same problem. They do lots of aircraft parts with lots of pockets. We've built four drying rooms now, 2 for him and 2 for someone else. As Ted said the secret is LOTS, LOTS of air movement. One room we did was roughly 12W x 20D x 8H with (2) 45 kw electric fan forced heaters. Customer was pleased with drying times that didn't require lots of blowing off.

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Msg. #4234 in ** Ask Plater B**
Posted on 11/01/93 at 00:30:22
To: VALENTINUS BRINKMANN From: KEN ROSENBLUM - Reply To 'shop questions'
Thanks, Ken

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Msg. #4857 in ** Ask Plater B**
Posted on 03/05/94 at 08:16:07
To: ALL From: PAUL PETERSON - Danglers for Automatic Imperial barrels Is anyone out there using Imperials button barrels on one of their automatic machines. If so what kind of life do you get out of them. Has anyone tried anything unique with danglers in one of these oblique automatics. We plate large nails and bolts which tend to tear up the danglers. I am looking for any suggestions on alternative contacts.

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Msg. #4859 in ** Ask Plater B**
Posted on 03/05/94 at 09:40:29
To: PAUL PETERSON From: TED MOONEY - Reply To 'Danglers for Automatic Imperial barrels'
Just a quick thought, Paul-- Have you tried danglers an inch or two shorter?

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Msg. #4860 in ** Ask Plater B**
Posted on 03/05/94 at 19:28:00
To: PAUL PETERSON From: BERL STEIN - Reply To 'Danglers for Automatic Imperial barrels'
Paul: A flat ring or disk contact attached to the bottom of your oblique barrel might do a much better job than a dangler with parts of your configuration. You'll have to strip them periodically, but done right such modification could make your life a little easier. Good luck, Plater B

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Msg. #4861 in ** Ask Plater B**
Posted on 03/06/94 at 15:21:36
To: TED MOONEY From: TED MOONEY - Reply To 'Danglers for Automatic Imperial barrels'
I still think danglers are usually the way to go because a disk contact rotates, requiring a contact brush arrangement which is often an even bigger headache. Just shortening the dangler so it sits on top of the load, barely into it, should make a big improvement. If the current situation is that the dangler is all the way to the bottom of a heavy load of large bolts it experiences an awful lot of hard twisting, tearing action because it is serving as an agitator.

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Msg. #4866 in ** Ask Plater B**
Posted on 03/07/94 at 08:16:14
To: TED MOONEY From: BERL STEIN - Reply To 'Danglers for Automatic Imperial barrels'
My experience with danglers & asymmetric parts in oblique barrels wasn't that pleasant, but I have never had to deal with large perforated ones. When the barrel is not perforated, a reliable brush assembly is rather easy to rig up. Also, with small perforated barrels, a brush/slip ring assembly can be mounted on the shaft that the barrel rides on. Plater B

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Msg. #4873 in ** Ask Plater B**
Posted on 03/08/94 at 16:33:19
To: PAUL PETERSON From: RON LANDRETTE - Reply To 'Danglers for Automatic Imperial barrels'
AS FAR AS IMPERIAL,I TAKE IT YOU HAVE A RETURN TYPE MACHINE,IMPERIALS VERSION OF A MODEL E. BUTTON CONTACTS CAN BE RETROFITTED TO YOUR EXISTING CYLINDERS AND LIFE OF THE BUTTONS SHOULD NOT BE TOO BAD,THE CONTACT ASSY OF THIS UNIT IS FRIENDLY TO A CONVERSION SUCH AS THIS. COSTWISE,YOU ARE NOT LOOKING AT A CHEAP PROPOSITION. I CURRENTLY HAVE AN ACCOUNT USING 4/0 DANGLERS,.900 OD WITH A FULL LENGTH PROTECTIVE SLEEVE @ 1.250 O.D.. THEY SEEM TO GET A GOOD LIFESPAN OUT OF THESE. THIS DOES HOWEVER REQUIRE OPENING UP THE HOLE IN THE SIDE OF THE BARREL TO 1.25 TO ALLOW THE DANGLER TO PASS THRU. FURTHER,THEY FABRICATED SOME CLAMP BLOCKS TO KEEP THE REMAINDER OF THE DANGLER NEAR THE BARREL. CALL ME VIA VOICE 203-589-5799 [RON] IF YOU WANT TO LOOK INTO THIS FURTHER

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Msg. #4874 in ** Ask Plater B**
Posted on 03/08/94 at 16:37:40
To: TED MOONEY From: RON LANDRETTE - Reply To 'Danglers for Automatic Imperial barrels'
TED,I AGREE IF THE LINE IS A HORIZONTAL AUTOMATIC,THESE ARE NOT FRIENDLY TO THESE CONVERSIONS AND ARE A MAINTENANCE HEADACHE. IF IT IS AN IMPERIAL RETURN AUTOMATIC [LIKE A STEPHENS E] THE BRUSH CONTACT IS ALREADY ESTABLISHED AND THE BARRELS CAN BE CONVERTED TO A DISK/BUTTON SETUP PROVIDING THE CUSTOMER STAYS ON TOP OF STRIPPING ETC...

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Msg. #4883 in ** Ask Plater B**
Posted on 03/08/94 at 22:38:23
To: RON LANDRETTE From: TED MOONEY - Reply To 'Danglers for Automatic Imperial barrels'
Thanks, Ron, I'm sure you're right. I used to work for a barrel manufacturer and we built and repaired Model C's and E's and BP-1000's and so on, but it's been a while since I really looked at how these oblique barrel contacts are assembled. By the way, if you think of it, release your caps-lock key. You've got a lot to tell us on this subject but it's a bit hard to read on some of our screens when it's all-caps.

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Msg. #4884 in ** Ask Plater B**
Posted on 03/09/94 at 10:17:35
To: TED MOONEY From: RON LANDRETTE - Reply To 'Danglers for Automatic Imperial barrels'
Thanks Ted,capslock released. The contact system on these units utilizes 2 heavy [2"x 3"] copper blocks,spring loaded,with a jumper,radius cut into each,they mate on a common shaft. the entire assembly being above solution level. This corresponds to my documentation on the imperial return machine.

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