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Chrome Plating Problems on Gravure Printing Cylinders/Rolls

 

Chrome peeling problem: We gravure print using chrome plated cylinders. The cylinders consist of a steel base which is copper plated then engraved for the print image. A copper plating is then applied over top to extend the life of the cylinder in the press. In gravure the cylinder is partly immersed in ink. The cells of the engraving fill with ink. As the cylinder turns the excess ink is wiped from the non-image area by a metal blade. The cells transfer the ink to the paper as they contact at a nip and the process begins again.

We have been experiencing a chrome peeling problem with our cylinders. The problem has been most prevalent with one of three suppliers, but all three have had peeling to some degree. The chrome "bubbles up" and peels off in select non-image areas of the cylinder. This never happens the first time they are used in the press. Usually it happens the second or third time we use them to print. We talked with the cylinder supplier who insists that their product is up to spec. They suggested we talk to our ink supplier. We use water-based inks (pH 8.5 - 9). We have talked to other manufacturers who use these inks in similar processes without problem.

The press we print with is a little unique in that it uses inferred drying units (positioned approx. 1 ft from the cylinders in the press).They cylinders are stored on metal racks, uncovered in our warehouse in between use.

I have provided as much details as possible in hopes that someone may have an insight into the cause of this problem. It would be much appreciated.

Thanks,

Bill Landis
- York, Pennsylvania, USA


 

A. Bill:

The peeling and blistering problem is most probably in the preparation of the copper before chrome plating. Even though it is well known that chrome is not impervious due to its micro cracking, the copper beneath it is very corrosion resistant to all kinds of commercial inks. This means that even if the ink could penetrate through the chrome cracks and reach the copper, it will not be attacked. Another possibility is an excessive thickness of chrome (more than 1-2 mils which I don't think is your case). Then the problem becomes of mechanical nature (internal stresses and their distribution through the chrome layer). Finally, have you checked the blade pressure with the machine manufacturer?

Good luck,

Guillermo Marrufo
Monterrey, NL, Mexico

Hard Chromium Plating


 

A. Hello Bill,

I suggest you to check following items:

Cracks going across the chrome layer due to

* thin layer thickness
* too high surface pressure
* weak plating quality
(consequence: corrosion under the chrome layer and the effect is visible as bubbles)

Insufficient adhesion of copper on the base material. (consequence: chrome bubbles off and peels off because the chrome pulls the copper off due to internal stress).
Possible causes: too much brightener, insufficient pretreatment, etc.)

I wish you a successful trouble shooting.

Michael Hekli (Switzerland)
Hartchrom Inc.

Watervliet, New York



 

A. About 20 years ago I was asked to look at a chromium plated printing plate used by a well known UK printing company. Their problem was very similar to what I think is being described here, but they only had the problem with one type of green ink. I do not recall if it was water-based or not, but I do recall the pH for the ink was quite low. Examination of the failure showed it to be localised in the engraving and was similar to what would be expected by erosion corrosion caused by micro-particles in the ink. That is, where the ink, that has been squeezed into the engraving, comes into contact with the edge of the engraving, the chromium showed signs of erosion corrosion. This in turn then allowed the low pH ink to start interlamellar corrosion to occur, resulting in de-lamination of the overcoats at the interface of the over layers. I hope this may offer an insight into what is going on.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK

Rotagravure: European & American Methods


 

A. This corrosion of Gravure cylinders isn't uncommon. The problem usually occurs after the cylinder has been run on a press, and then stored before the next print run. After around 4~500,000 meters of printing, the Cr deposit thickness will be reduced by around 30~40%. If the copper preparation isn't thorough enough,or, the Cr deposit isn't as thick as you think it is, then corrosion can occur in pits or adhesion can suffer.

n UK around three or four years ago, we had a lot of this problem. One main reason was that, printers changed from organic solvent based inks to water based. With the organic based inks the printer didn't have to be so careful about cylinder cleaning before storage. With the water based inks, cleaning is much more important.

We spent a long time working with customers and printers to improve there housekeeping and production methods. Another problem was Cr thickness. The customers thought that they were plating 10~12 microns, but in fact were only plating 8. After the cylinders had been polished they where down to 6 microns, and by the time the cylinders had been run on a press and put into storage, there was only 3~4 microns left at most. When the printers tried to run the cylinders a second time, the Cr would flake off the copper surface.

The surface area of an engraved cylinder is in reality much larger than the sum of its dimensions would suggest. So customers have to allow some extra time to deposit the thickness they think they are.

We also looked at cylinder storage at printers. New, and used cylinders must be kept dry and clean at all times. After printing they must clean and dry the cylinder thoroughly, then wrap and store the cylinder properly.

If these points are looked at, then you will be able to cure this problem.

Hope this helps.

Regards,

Jonathan Timms
- Hong Kong


++++++

A. Due to the micro crack structure of the hard chrome and the fact that the solvents used in cleaning cylinders after printing attract moisture, oxidation of the copper takes place under the chrome layer.you will see this by looking at the colour of the exposed copper. I have found that a thin wipe of light oil and to wrap the cylinder in plastic solves the problem.

Shaun Grenfell
printing - Durban, South Africa


November 27, 2011

A. Regarding the chrome peeling:

Is the chrome peeled off from the copper or do you see after the print the steel base (or the nickel deposit?)
Where does the chrome peels off, is it on the radius in majority? If yes, the use shields in order to avoid excessive build ups and ask your printers (if they are already not doing it to cut the blade ends approx. in a 45 degrees angle and 50mm wide, if the blade oscillation is on and running about 10-15mm across the cylinder then the blade has a relaxation area.
Do you use filters in your ink, any metal particles in?
Any difference by using different inks on different units?

5-7 micron is enough to print around 1.5 - 2.2 million cylinder revolutions. Please consider that above these thicknesses you may cause a build on cell rim between the wall, that also could led to a "rip-off" during the print, especially if the angle and blade pressure as well as the impression roller pressure is too high. As low as possible from everything, as you longer you enjoy your print run.

Kind regards,
Dominik

Dominik Michalek
- Melbourne, VIC, Australia

Rotogravure and Flexographic Printing Presses



How to check chrome hardness

+++

Q. Is there a way to check chrome hardness on a gravure cylinder with a coating thickness of approx. 3 tenths of chrome plated over 15 thousandths of copper?

Jack Manifold
graphics - Toronto, Ontario



What causes the chrome to corrode?

++++

Q. I am the superintendent of printing operations for a large manufacturer of paperboard packaging in the fast food industry. Our printing operation uses rotogravure technology. The gravure printing cylinder is a steel base plated with nickel, copper and finally chrome. In operation the cylinder is bathed in printing ink and wiped clean with a carbon steel doctor blade. To clarify, two unlike metals, carbon steel and chrome, are in constant contact with an alkali solution between them. Under certain common conditions the chrome plating is susceptible to corrosion. These conditions include the use of blue ink which contain higher concentrations of metals than other colors. Additionally the use of ammonia to maintain printing ink Ph at levels between 8.0 - 9.5 is considered to be a contributing factor.

Can you help me understand what is causing the corrosion condition? I have not been able to narrow down what exactly is causing it. The gravure industry faces stiff competition from the flexographic industry and struggles to maintain environmental compliance. This corrosion problem is yet another nail in the industry coffin. Help me keep the gravure association alive.

Kevin Moody
- Stockton , California, USA


++++

A. Chrome is not very resistant to corrosion, certain types of inks will attack it, but it is very hard. That's why you use it on top of your engraved rolls. Copper in turn is soft, very corrosion resistant and much more noble (galvanic potential against chrome). I think your best chances would be to find more friendly grades of inks. Also, there are special chrome baths prepared to increase the corrosion resistance. One is called microcracked or porous chrome and the other is called thin-dense chrome. It may be worth investigating their suitability for your situation.

Guillermo Marrufo
Monterrey, NL, Mexico


Chromium plating is rough

++++

Q. In electronic copper plating we are getting hardness of 220 hv. Copper Sulphate is at 240 g/l and sulphuric at 65 g/l. But upon hard chrome plating on it we get roughness on the cylinder. Is it because of high sulphuric in the copper bath effecting the hard chrome or some problem in the chrome bath? Do we have to increase the bath concentration for chrome plating of hard coppered cylinders?

Dhritiman M deleted
rotogravure - Mumbai, Maharashtra, India


++++

A. What is the hard chrome bath you are using? If you are using HENE process, then try increasing sulphate content in hard chrome bath to ratio 100:1. If you are getting roughness in copper bath, then give activated carbon treatment to the copper bath.

N.K.Praveen Kumar
- Secunderabad, ANDHRA PRADESH, iNDIA



Chrome wears out on white cylinder in 15 days

November 19, 2011

Q. Dear Sir,
I am facing a very big problem is that our rotogravure printing cylinders, especially white cylinder, are worn/chrome damaged after 15 days continuous run. What will be the reason and give solution please.
Regards

Ak Viswan
- Fujairah, UAE

November 28, 2011

A. Dear Mr AK Viswan,

White ink is a very abrasive ink which leads pretty quick to an excessive wear of blade and chrome surface. Right choice of white ink supplier + right choice of brand and type of doctor blade gives you longer run times. Also the roughness of the polished chrome surface and its pattering plays an important role.
However, some further adjustments can be done in your pre-press as well at your press area in order to achieve major results by lower running costs.

Kind regards,
Dominik

Dominik Michalek
- Melbourne, VIC, Australia

March 3, 2012

A. Good day for all

1. Cylinder peeling off
- Method of cleaning:
(cylinder surface must be clean - to wipe with oil and to wrap with plastic)
- Method of storage:
(Must keep at dry area )
please check how long the last print, 6-12 month

- To check the mileage of cylinder print:
(The best is from 750k meters - 1.5 mil meters and sent for chrome. re chrome is cheaper compare to make new)

- To check the quality of cylinder supply from vendor:

2. White cylinder worn off (cell shallow)
- for your information white ink contains TIO2; it makes cylinder plating very fast worn off. The max for the shell life is around 1 millimeter - 1.5 millimeter and depend on your control of doctor blade pressure and machine speed. 15 days run without non stop is huge.
My advise, you should go for 2nd set of cylinders.
In my country new cylinder cost is USD 400.00 only.

All the best

Zul Rahman
- Kuala Lumpur, Malaysia


December 11, 2012

A. Don't forget a regular analysis of your ink; it's very easy for a supplier to "miss" out certain lubrication additives to save cost.

Garry Williams
- Liverpool, United Kingdom



How to plate good chrome on variable quality copper layer

July 18, 2012

Can the hardness and thickness of the copper plating effect the final chrome layer? If so how can this be overcome?

Craig Irvine
- Durban Kwa Zulu Natal South Africa


July 18, 2012

A. Hi Craig. When it comes to plating, everything affects everything :-)

I am assuming that you are speaking of gravure rolls? If not, please clarify. I think you are asking if you can apply the chrome well enough and thick enough to make the properties and condition and performance of the chrome plated surface independent of the underlying copper plating layer and unaffected by it. Sorry, but I don't think that will work. Certainly the hardness and thickness of the underlying copper will affect corrosion under the chrome and cracking and other problems with the chrome.

It is very difficult to answer generalized questions because they always involve a hundred "Ifs, ands and buts", but if you can explain your individual situation instead of casting the proposition in the abstract, I think the readers can help you solve your problems. Good luck.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

Short life, with lines and scum problems

October 20, 2012

Q.
We are constantly facing issues of early wearing out, short life, and lines / scum problem of the chrome plated cylinders supplied to our customer.
The expected run of the cylinder is around 1.5 - 2.0 million impressions per re-plate.
But after printing 25% of this quantity, the cylinder starts giving lines and scums on the substrates. Also sometimes the cylinder gets worn out early.

Please suggest.

John Deka
- Dubai


October 24, 2012

A. Hi.
To just state cylinder wear is not enough information. Firstly ASSUME your cylinders are within spec, then you can start to look at quality of ink, blade pressures/angles nip points, etc.
Sorry to be so vague, but so is the subject; we have had very similar issues here, but all can be eliminated with the correct approach.

Garry Williams
- Liverpool, Merseyside, England


October 27, 2012

A. Hi John,

What are your chrome parameters and properties vs product of print? How is your surface quality (roughness value and pattern)?

Regards,

Dominik Michalek
- Melbourne, VIC, Australia


October 29, 2012

A. Hi,

The temperature in your pretreatment bath is too low.

Regards

Anders Sundman
    surface finishing engineer
- Malmo, Sweden

November 1, 2012

A. Here is an example of classic wear, which starts on the edge of the cylinder and gradually moves in:

cylinder wear 1 cylinder wear 2

Normally, far too high a blade pressure, trying to achieve a clean wipe, when changing the blade and/or angle would have worked.

Garry Williams
- Liverpool, Merseyside, England


June 8, 2013 -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. Dear Sir/ Ma'am,

We are rotogravure cylinder manufacturer from India. We have observed very frequent issue of white cylinder worn out in very less quantity. Can someone share their experience on same and what could be solution to avoid this.

Thanks & Regards,

Parag Patel
- Gujarat, India


June 13, 2013

A. Hi Parag. We appended your inquiry to a thread about the subject which should give you plenty of food for thought. If any comments sounds promising but need clarification for your particular case, please let us know. Thanks.

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

September 22, 2013

A. Hi Parag,

white inks are usually the most abrasive inks and require bit more attention regarding print settings and surface finishing of rotogravure cylinders.

Dominik Michalek
- Epping, VIC, Australia


September 17, 2013

Q. Good Day,

Regarding question about scum moisture problem on the Cyan Cylinder: mostly we are facing scum into the cylinder but, when we press the blade, scum is coming out, then after 5 to 10 mins is coming back again.

Lyle Miranda
packaging - Lagos, Nigeria


September 22, 2013

A. Hi Leila,

Scumming problems can have various causes. Please review your engraving and chroming parameters, but also your print settings such as doctor blade, oscillation of doctor blade and the type of doctor blade.

Kind regards,

Dominik Michalek
- Epping, VIC, Australia



Chrome pitting issue

January 12, 2014

Q. We manufacture gravure roll. I'm facing chrome pitting problem. Please suggest to me.
Chromic acid-250 gpl
Sulfuric acid-2.5 gpl
Trivalent chrome-3.5
hardness-990 hv
calalyst-170
Crack-1850

Should I increase or decrease any of above mentioned for reducing chrome pitting?

Komal Kumar
plating shop employee - Rudrapur, US, Nagar
  ^- Privately contact this inquirer -^


January 14, 2014

Q. We are facing small dents (sometimes damage in the non image area) on the printing Cylinder after engraving and also after chrome the cylinder in the image area or non image area!! What are the process or technique to fill-up the dent or damaged area except polishing by emery paper?

SUJIT DAS
- Kolkata, W.B., India
  ^- Privately contact this inquirer -^



Ink lines on gravure cylinder

January 31, 2014

Q. We are facing a problem of ink lines occurred on non-engraved area of gravure cylinder. This happens mainly when the printer runs the cylinders beyond 140 m/min. speed.
Can any one suggest the possible cause and idea to get rid of it?

Bhavesh Patel
- Gandhinagar, Gujarat, India
  ^- Privately contact this inquirer -^


February 4, 2014

A. Hi,

You need to be more specific regarding ink lines, they could be hazing, scumming, color streak and/or drag out. Also the tone density of these ink lines are important since this leaves the clue of what could be the root cause.

Dominik Michalek
- Chonburi, Thailand


April 21, 2014

A. Hi!

I'm in a big company that produces printing cylinder in China, so maybe I will analyze it more from the printing cylinder. The possible causes as follows:
1. wound in the surface of printing cylinder --
- check the surface of printing cylinder; if find wound you can re plate with chrome.
2. the polishing is not good on surface of the printing cylinder --
- you can polish the surface with fine sandpaper when the printing cylinder is rotating in the printing press, but you must be careful and not to injure the printing cylinder.
- you also can ask the printing cylinder factory to polish it again.
3. dirt on surface of the printing cylinder --
- you can clean the printing cylinder with some cleanout fluid; sometimes the printing material will also make the printing cylinder soiled when printing.
4. doctor blade(very important) --
- doctor blade have a gap sometimes,maybe you can try with a new doctor blade
5.ink (very important) --
- ink particle size is too big.
You need make dilution for ink or other ways
6. the printing material
- such as the printing material is paper.
7. the quality of printing cylinder, such as quality of chromium, the balance of dynamic balance, the printing cylinder is not very round --
- so maybe you can ask the printing cylinder to make a better polishing on the surface of printing cylinder. It is also good to engrave a very very light pattern on the part of non-engraved area of gravure cylinder, sometimes it can avoid the ink line or white dot.

The above is only my opinion. This is my private opinion and a reference only.

Bert Gu
produce all kinds of printing cylinders - Donggguan city,China



Chrome scumming on gravure unit

October 3, 2014

Q. We have an issue of chrome polishing (scumming) on the cyan unit. It is more frequently happening on one unit (7) on the wire side of the unit and not as frequent as unit 2 the smooth side. The ratio is 5 2 1. They have increased the catalyst to harden the chrome, and the ink grind is less than 1 µm. We have added PTFE and castor oil as a slip additive which has shown a slight improvement but problem still persists. Any recommendations?

David Meeser
printing inks - Cape Town Western Cape South Africa
  ^- Privately contact this inquirer -^



Chrome is "Frosting" on wbore gravure cylinders

October 7, 2014

Q. I work for a gravure company that manufactures print cylinders. We use wbore and shafted style cylinders . All of a sudden whenever we chrome a wbore cylinder it frosts. The shafted cylinders come out fine. We've replaced and checked all the connections and everything looks okay. Any ideas?
Thanks
Donald

Donald Bryant
- Canterbury, Connecticut
  ^- Privately contact this inquirer -^


October 2014

Hi Donald. A pic might help as I'm not sure we all envision the same thing when you say "frosting" -- that sounds to me like "burning". I'm not familiar with the term wbore, but from context it sounds like a hollow cylinder?

Regards,

pic of Ted Mooney Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey

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