Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site

Problem? Solution? Chime right in!
(one of the world's very few 'no registration' sites)

-----

"Anodising rectifier and power requirements"

Current questions:

August 8, 2021

Q. Planning to install a 5000 square feet per 8 hour shift capacity of anodising plant. Help me with the rectifier capacity, how much area can be done per load and how much time required to do per load? Thanks in advance.

Syed Imran
Proprietor - Chennai, India
^


August 8, 2021

Q. I am planning to install a aluminium anodising plant of 4000- 5000 square feet of Type 2. Section length would be not more than 16 feet.
Coating thickness is not more than 5 micron (as per the practices done in our country). Suggest me the rectification capacity, how much surface area can be done in per load and anodising time to be given.

Faisal hussain
Proprietor - Tamilnadu, India
^


August 2021

A. Hi Syed. If you're planning on running 24/7 you can divide your 5000 square feet by your 8 hours to determine your hourly production. But if you're planning a single shift, remember that it will take 1-1-1/2 hours before the 1st part is finished each day, so you'll have to divide the 5000 by 6-1/2 -- it's a pretty big difference.

The next question is what thickness do you need because the required time to process a piece will be roughly proportional to the thickness. If you're doing architectural work, or parts to be dyed black you may need 0.0005" to 0.0008" thickness, say an hour of anodizing time depending on the alloy, but other work of 0.0002-0.0003" thick and other alloys might take only half an hour of anodizing time or even less.

With these numbers, and planning on anodizing at 12 ASF you should be able to do the arithmetic. It's probably better to size the new rectifier for 18 ASF though, and a 24-volt rectifier is probably a good idea.

----

Hi Faisal. Your questions are very similar to Syed's, so the answers are as well. Rectifier voltage and anodizing time vary with the alloy, but probably 20-25 minutes for 5 µm / 0.0002".

It is always a good idea to retain an experienced consultant because readers are probably happy to answer your questions but if you haven't done this before you're likely to not ask some important ones :-)

Luck & Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Aloha -- an idea worth spreading
finishing.com - Pine Beach, New Jersey
^




Closely related Q&As, oldest first:

1997

Q. I have a question about the capacity of my sulphuric acid plant for architectural aluminium. Our plant uses horizontal tanks and we have an electric powered hoist. Given that it takes approximately 30 minutes for a 12 micron coat, I figure that I can get 48 loads in 24 hours. However, my folks in production insist that no matter what they do it is impossible to get more than 24 loads. Is this correct? Would anyone have suggestions on how to increase the number of loads we get per day?

Thanks,
Sanjay

Sanjay A. Bulchandani
- Bombay, India
^


1997

"Surface Treatment & Finishing of Aluminium and Its Alloys"
Wernick, Pinner & Sheasby
from Abe Books
or

(affil. link)

A. Hi Sanjay. Things need to be in proportion: a sports car would not have 1 steering wheel, 1 seat, 1 hubcap, and 1 radio speaker; rather, it might have perhaps 1 steering wheel, 2 seats, 4 hubcaps and 6 radio speakers. So too when one designs an anodizing line, it is usually not a matter of having one of everything, but of deciding how many of this item and how many of that are needed to keep things in proper productive balance.

If you have the same number of anodizing cells as cleaner, etch, desmut and rinse cells, all of the latter are condemned to being empty virtually all of the time--probably not a very cost effective approach!

30 minutes sounds on the light side for architectural anodizing anyway; I would probably design such a line so that it has at least 2 anodizing cells. Depending on the size and the number of steps, you might also want two hoists as well, since an operator may not be able to complete all of the steps in fifteen minutes.

I can't really say for sure without more information, but on first impression I agree with you: 24 loads per 24 hours may be too few to be economically feasible, and even 48 sounds like a rather leisurely production pace if you have the hoists and the people. Good luck.

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^


1997

A. Assuming that you have one anodize tank and are happy with the product, the only way you can get a significant increase is to have about 3 hoists, 6 or more complete sets of fixtures and enough people to rack, unrack, run and pack. Theoretically, you might have a load every 35 minutes from one tank if everything was very well organized, and no breaks, no eating or adequate fill in help.
If you want to find out what is wrong, go work, not watch, on the line for a full shift for a complete week with no meetings or phone calls. I predict that you will find it very enlightening.
Be ready to open your pocket book for more equipment and improvements and you will see improvement.

Ted's line design comments are very valid.

James Watts
- Navarre, Florida
^


1997

A. What I would recommend is that you stay on the production line as long you can be. Doing so you will notice an instant production raise.The anodizing tank is the bottleneck of a line but if you are employing at least two hoists I think you can get at least 38-40 loads/day.

Guillermo Luna
- Mexico City, Mexico
^


1997

A. Hello Sanjay,

I am sure you won't remember my face. But I did visit your plant at Thane as well as your office on different occasions between 1992 and '93. In all the occasions, I was asked these type of questions casually, especially at Thane. And I do remember saying the similar words as Ted Mooney and others in the thread have mentioned here.

If you really want to increase the productivity, you got to increase the no. of tanks and hoist and also the manpower. However, I always felt that with existing facility, you could increase the productivity at least 40 to 50% max by proper planning and motivation of the plant personnel.

PS: Standard Disclaimers apply.

Best wishes,

Gautam Banerjee, Ph. D.
India
^



To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



2002

Q. 1. I am required to sulphuric anodise a component with a surface area of approx. 7 sq mts. What is the best way of calculating how much power is required and if the existing rectifier will cope. Also is there an anode to cathode surface area ratio which must be taken into account.

2. Given the details above if the rectifier is 24V 1000A would this be capable of anodising the component at 7 sq. mts. surface area.

Ian Beckwith
- United Kingdom
^


2002

probert book
Aluminum How-To

"The Chromating - Anodizing - Hardcoating Handbook"
by Robert Probert
(How good is it? Finishing.com has sold over 700 copies without a single return request)

A. The 24 volts would be plenty; 15 volts would probably be adequate for some alloys. But I figure 7 square meters is 75+ square feet. That means your maximum possible current density would be 13.3 ASF. That might be okay as an operating plan, but marginal for a purchasing plan. A new anodizing rectifier for the future should probably be sized for about 18 ASF.

I wish the rest of the world would enter the 21st century and start using our complex & impenetrable foot-pound-second system instead of the simple metric system :-)

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^


2002

A. Ian,

Your rectifier should be plenty if you are doing type II anodizing ... you will not have enough volts to do type III. I don't have my conversion chart here at home (I don't think we Americans will ever totally convert to the metric system), but you want to anodize around 12-15 amps per square foot of surface area (for type II), so.. 1000 amps will be plenty. I'm not sure if you were asking what the work to cathode ratio should be.. but you want to keep it around 3-1 (work to cathode).

Marc Green
Marc Green
anodizer - Boise, Idaho
^


2002

A. I somewhat stand corrected..thanks, Ted..I mis-calculated the meter-to foot number...however I believe his 1000 amps will BARELY be enough to anodize at 13 asf. Ya'll remember..back in grade school..when they said "10 years from now, EVERY country will be using the metric system"...sheeesh..its been almost 20 yrs.. and we STILL aren't there.

Marc Green
Marc Green
anodizer - Boise, Idaho
^


2002

A. I've designed many anodizing lines and I'm sure I designed for more than that, but I don't actually run the lines, Marc, so I yield to your actual experience; I thought 13.3 ASF was low but Robert Probert's book says 12 ASF.

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^


2002

A. You're correct, Ted, he would be pushing the limits -- but I guess I tend to look at things from a different point of view sometimes. I got the impression he had a job he needed to get done, and assuming it wasn't going to be an ongoing production job where the purchase of another rectifier could be an option, that he could "get by" using his current set-up. Sometimes ya just gotta wing it a little bit in our business as long as quality isn't affected. And while running at 13 asf may take a wee bit longer to get his desired thickness, I still believe he could achieve a quality product in the end. (Go St. Louis Blues!)

Marc Green
Marc Green
anodizer - Boise, Idaho
^



Rectifier size for a Small Anodizing Plant

December 9, 2009

Q. We are basically a converter for Rubber Blankets. Our activity involves cutting printing blankets in specified sizes (normally rectangular shape) and then fixing aluminium sections on leading and trailing sides of rectangle after applying industrial adhesives. Aluminium Sections are in "U" shape. Adhesive is applied inside the "U" and thereafter it is pressed on Press Brake Machine.

We need to put up an anodizing plant for anodizing Aluminum Sections (Maximum Length of 42"). Height of sidewalls of "U" is 15 MM, Bottom thickness of "U" is 5 MM & length of Section will be 42". We shall be doing this for a quantity of 50 pieces per day.

Please suggest the how to decide the capacity of rectifier?

Sanjay Chhokra
Regulator - Nagpur, Maharashtra, India
^


December 11, 2009

A. Hi, Sanjay. You can roughly size the rectifier as 18 volts, 20 amps/square foot of aluminum being processed at a given time. But this raises the question of whether you will be anodizing one combined batch of 50 parts once a day (probably impractical), individual pieces 50 times a day (probably impractical), or something in between like 5 batches per day with 10 parts in a batch, or 10 batches per day with 5 parts in a batch. You might look for local help in working out the possible approaches.

Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^


May 11, 2010

A. Use 100 ampere rectifier with 16 or 18 volt it will be sufficient for you.

Sumit Lodha
- Ahmednagar, Maharashtra, India
^



January 21, 2014

"Surface Treatment & Finishing of Aluminium and Its Alloys"
Wernick, Pinner & Sheasby
from Abe Books
or

(affil. link)

Q. I have an anodizing plant with rectifier size of 24 V, 2000 Amps, using sulfuric acid of 165-170 gm/litre. Size of anodizing tank is 21' x 3' x 3'. We are applying current density of 13 Amps/Sq. ft. for a period of 30 minutes with the batch load being 100-120 Sq. ft.

The problem is with electricity consumption. Actually I am confused with electricity consumption. Right now the electricity consumption is 27-28 units (KW-hr) per batch. Please let me know what should be the actual electricity consumption per batch. Also for information my chiller is of 10TR, cooling tower pump, condenser pump, chilled water pump each of 2 HP. Please guide.

Regards,

Rahul Mogal
- Nashik, Maharashtra, India
^


January 28, 2014

A. Hi,
To calculate the energy that you use we need voltage, current and time of processing. We have the time. You give the current density at 13 ASF. Taking a batch load of 110 sq ft (the mid-value), the current is
110 * 13 = 1430 amps.
I guess that the voltage is greater than 16 and less than 20, so let's take 18 volts.
Power used is
18 * 1430 = 25740 watts = 25.740 kw
Time is 0.5 hours so energy in kwh is
25.740 * 0.5 = 12.87 kwh
If the efficiency of your power supply is 80% then load on supply is 12.87 * 100 / 80 = 16.0875 kwh. There is a big difference between the the calculated kwh and actual.
There are 3 possible explanations:
1) I have made a mistake in the calculations
2) The figures I have used are incorrect, especially the assumed efficiency
3) The kwh (27-28) that you quote includes the cooling demand.

Regards
Harry

harry_parkes
Harry Parkes
- Birmingham, UK
^



March 26, 2014

Q. Hi
I am looking to add to my current factory a type III anodizing facility.
I have 2500 x 200 x 1300 mm Anodizing tank. With a 10-20A; 500-2000V Transformer (can I use this or do I have to upsize?) and will a 240V-250Amp electricity supply be enough?

The Type III plant needs to be a min L x W x H of 2000 x 800 x 1200 mm.
How can I calculate the specifications, including power requirements for Chiller and Rectifier.
Finally what method of chilling is best, direct or indirect. I see some pipes in lead whilst I have been informed that titanium pipes would be better.

Is there anyone who has set up a Type III plant who can start us off in the right direction.
Any help from those who have had a hand in setting up a similar setup would be appreciated.

James Morford
Photofabricators - Durban, Natal, South Africa
^


March 2014

A. Hi James. Setting up a hard anodizing plant is a large undertaking which, in my opinion, ought to involve retaining an anodizing consultant. You might look at our Directory of Consultants.

But to your specific questions, there appears to be a typo in your question since you say your available tank is 200 mm wide and you need a minimum of 800 mm wide. If it's actually 2000 mm wide, it could hold two loads at a time, which might be useful -- but hopefully you realize that an anodizing line requires a lot more tanks than one :-)

You need to start with the area of the load, and an estimate of the required Amperage and voltage -- perhaps 30 ASF at 75 volts. From this you calculate the rectifier size and the transformer size.

This would give you the maximum instantaneous cooling load, but recognizing the anodizing solution in the tanks and the cooling water reservoirs, etc., the system will have some thermal inertia/momentum, so you probably don't have to size the cooling system for quite the maximum instantaneous load, maybe 75%-80% of it.

I think titanium is a better bet than lead, and that an external heat exchanger is a better idea than cooling coils in the tank. Don't forget a really powerful air agitation system (or eductor system) for hard anodizing. Good luck.

Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^



Can plating rectifiers be used for anodizing?

December 30, 2015

Q. Hello everyone!
I recently ran some initial testing parts for anodizing type II with my nickel line rectifier, but few days later I was told that this electroplating rectifier might get damaged running anodizing, does anodizing require a different type of rectifier?
Thanks

Alberto Nunez
electroplating - Brownsville Texas, USA
^


December 2015

A. Hi Alberto. Anodizing tends to require more volts and fewer amps than most electroplating. (Most plating operates at about 4.5 to 9 volts, whereas anodizing will take 12 to 18 volts; many metals are electroplated at about 30 to 40 ASF, whereas anodizing will be about 12 to 18 ASF.

But the biggest difference is that you have to start anodizing at low voltage and slowly ramp up. That's because (per Ohm's Law), current is inversely proportional to resistance, and there is very little resistance in raw aluminum, but a lot of resistance in anodized aluminum. If you don't start at low voltage you'll burn the parts; if you stay at low voltage, you won't build anodizing thickness.

But damaging the rectifier? I don't think so as long as you turn it down at the start.

Regards,

Ted Mooney, finishing.com
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
^



To minimize search efforts and to offer multiple viewpoints, we combined previously separate threads onto this page. Please forgive any resultant repetition, failures of chronological order, or what may look like readers disrespecting previous responses -- those other responses may not have been on the page at the time :-)



June 26, 2016

Q. I am a fabricator of aluminium works. I want to set up a new anodizing plant. Please give suggestion for me.

NITIN KAPOOR
- INDIA,HIMACHAL PRADESH, HAMIEPUR
^


probert book
Aluminum How-To

"The Chromating - Anodizing - Hardcoating Handbook"
by Robert Probert
(How good is it? Finishing.com has sold over 700 copies without a single return request)

June 2016

A. Hi Nitin. You can review our Introduction to Anodizing for a quick intro to the subject, then you might be interested in Robert Probert's "Aluminum How To" or a similar book. But if you have no experience in anodizing, I would suggest that you not proceed without retaining an anodizing consultant. Good luck.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Aloha -- an idea worth spreading
finishing.com - Pine Beach, New Jersey
^



December 12, 2016 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Hi,

I wanted to know if a EMS 7.5-300 power supply would work for decorative aluminum anodizing. I am have made several failed attempts on 6061 and I think the size of the power supply is the reason? Any suggestions on what to buy?

david wasserman
- hockley,texas us
^


December 2016

A. Hi David. We appended your inquiry to an existing thread on the subject. You'll need at least 12 volts absolute minimum even for selected alloys, preferably 18 volts, whereas your unit generates only 7.5 volts. Sorry, it's not enough.You'll need an amperage capacity of, say, 18 amps per square foot of surface area you will be processing.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
Aloha -- an idea worth spreading
finishing.com - Pine Beach, New Jersey
^

Remaining questions on rectifier sizing for anodizing? Please see also --

Topic 12130 "Current/Voltage for Aluminum Anodizing"

Topic 0967 "Increasing Type III (Hardcoat) Anodizing Capacity"

Topic 23398 "Rectifier size (current, voltage) for Chromic Acid Anodizing"



none
finishing.com is made possible by ...
this text gets replaced with bannerText
spacer gets replaced with bannerImages

Q, A, or Comment on THIS thread SEARCH for Threads about ... My Topic Not Found: Start NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact    -    Privacy Policy    -    ©1995-2021 finishing.com, Pine Beach, New Jersey, USA