CASE STUDY

Pressroom Strategic Plan

A few weeks back we visited to perform a pressroom audit to better understand your concerns in the press department. We evaluated the causes and possible solutions to premature wear, anilox care and maintenance, and excessive downtime due to the anilox roll. We completed an on floor observation to witness pressroom concerns first hand. Below is a list of opportunities we feel will greatly decrease the level of wear your Company. From this memorandum, we will create a detailed strategic plan including timelines and responsibilities for each concern.

Anilox Wear:

Wear can occur for a number of reasons; I will address the most relevant concerns related to your company. After reviewing the audit, surface wear is a major concern. I can not speak for our competition but ceramic quality has a direct impact on the life of the roll. Other factors include ink systems, metering blades, contact area of metering blades, and overall maintenance of the anilox roll and inking system.

Possible Solutions

Institute a comprehensive training program to include a thorough understanding of ceramic and the process of manufacturing the anilox roll. I would suggest starting with a core group coming to Green Bay for a Walking Seminar™. (See attached form)

Create / incorporate a preventive maintenance program with the intent to focus on wear reduction. Create a check list specific your companies issues. Possibly request the maintenance department to be responsible for conducting the audit on a monthly basis. The audit should include, but not limited to: check stop pins in deck for metering blades, screws on clamps for metering blade holders, all anilox rolls are covered when out of press, bearings on anilox rolls…

Anilox Erosion:

Erosion occurs due to the solution used in the Ultra-Sonic cleaner. The corrosive level of 12 to13 pH will over time create erosion to steel and aluminum. Now with that in mind, the erosion is more prevalent on the aluminum bases than the steel bases. After reviewing the audit, 43 rolls in Fort Dearborn’s inventory are aluminum based. The purchase of aluminum bases addressed one issue, weight. Today we can manufacture a steel roll with a hollow core very comparable to the aluminum base weight. With the steel bases, you also can experience some erosion but nothing like the aluminum cores. You may see, over time, the numbers stamped on the side of the base become distorted, visually 3 to 4 years under normal circumstances. Engraving the necessary numbers in the dead band will also help this concern.

Solution

Purchase all steel bases with a hollow core to address the concerns with weight and erosion. I will address the concerns with the ultra-sonic cleaner in depth under cleaning of anilox rolls. To prevent erosion, we would need to eliminate the ultra-sonic cleaner. Based on the catalyst ink system, ultra-sonic cleaning is the most effective. As your company makes the transition from the catalyst ink system the need for the Ultra-sonic cleaner is also decreased. The current work level at your company using catalyst ink additives is about 25 %. Take that into consideration, and reality, 75% of all rolls can be cleaned by another method i.e.: Sodium Bicarbonate cleaner.

Edge damage is a prevailing concern noted in past roll audits performed. Edge damage comes from installation and removal of rolls to decks, racks, carts, and cleaners. The damage can cause a good printing anilox to create havoc with the metering blades and ultimately contaminate the inking system with ceramic chips. End -result scored anilox rolls and added cost to the operation.

Incorporate the use of roll covers at all times while rolls are out of press and cleaner. The expense of anilox covers is far less than the cost of the anilox roll.

Press side cleaning is the most critical aspect of the cleaning process. Anilox rolls should be thoroughly cleaned as soon as the rolls come out of the press to maximize ease of cleaning. CeramClean II works very well for that purpose along with good old elbow grease and a good stainless steel brush designed for ceramic rolls. You have the luxury of sinks at each press, making press side cleaning much easier. Allowing the ink to dry in the small cells creates a greater need for preventive maintenance cleaning. Another important point is a mild soap or just rinsing with water is not good enough because that will not remove ink that is already drying in the bottom of the cells. The procedure must be modified to reflect anilox cleaning (not rinsing) as soon as roll is removed. A sign off sheet can be added to the procedure that is monitored by management. (Create a sign off sheet)

Preventive maintenance cleaning is just as it is stated and not to replace press side cleaning. There are numerous mechanical cleaners in the industry for anilox rollers that are operative. The catalyst additive used does create some mechanical cleaning limitations, in my opinion.

Ultra-sonic cleaning is the most effective mechanical cleaner for ink systems with catalyst additives. The catalyst additive is designed to not rewet in simplest terms. The result is the ink does not rewet as standard waterbase ink and solvent based ink systems do, thus creating a difficult anilox cleaning process. Ultra-sonic soak tanks are a two-part system; the solution and the high frequency sound waves introduced into the solution. For best results the anilox must soak for 2 to 4 hours in a heated solution, depending upon the line screen of the anilox roll will determine the length of ultra-sonic cleaning. General guidelines (heat solution to 120 degrees) 800 line 2 minutes, 700 line 3 minutes, continuing the progression as the line screen decreases. The reason for the augment in time is the wall structure of the anilox roll is greater as the line screen decreases allowing the ultra-sonic portion of the cleaner to be increased. Many cases this type of cleaner damages cell walls due to over exposure to the ultra-sonic portion of the mechanical cleaning system. Another less common but prevalent concern is corrosion of the base as described earlier and contamination of the base under the ceramic. The pH levels of the solutions used in tanks today are what Harper would consider high. The problem comes to concern from the length of time the anilox is exposed to the corrosive solution. Over extended time the solution will seep through the porosity (pine holes) of the ceramic and attach the base, thus resulting in blistering or delimitation of ceramic from the base. All ceramic anilox rolls have porosity and Harper anilox rolls are less than 1% while the industry average is 3%. With all that in mind, I am recommending to only use the ultra-sonic cleaning system for the rolls that are exposed to the catalyst ink.

MicroClean cleaning system works very well for some and not so well for others. your company purchased an Ultra-sonic cleaner for a reason and I believe the reason revolves around the catalyst ink. The main concern with the MicroClean is the time the system takes to clean an anilox roll. I suggest we determine the effectiveness of the particular unit and base final discussions on the end result.

Sodium Bicarbonate cleaning systems have come a long way over the past few years. I have the most faith with this type of mechanical cleaning system because I’ve seen it work. The mechanical aspect of the system is very similar to the MicroClean system in rotation and theory. The big difference is the media, which has positive influence on the amount of time it takes to clean a roll. A 22” anilox roll, worse case scenario, will take 30 minutes to clean. To the best of my knowledge, neither the MicroClean nor the ultra-sonic system can come close to that. The media is blown onto the anilox roll and when the baking soda impacts the roll the media explodes forcing smaller particles into the cells breaking the ink away little by little. The maximum air pressure should not exceed 35 PSI to eliminate potential cell wall damage. The MicroClean is governed also by the media but it is not designed to explode. Please don’t misunderstand, the media does break down, but not at the level of the baking soda. The media size becomes very critical because the higher line anilox rolls have a smaller opening than the media particle size. I will schedule a demonstration with a Sodium Bicarbonate cleaning system to compare the effectiveness with both ink systems with your approval. Our next meeting I will bring the quote from Sani-Blast, Inc.

Banded Roll Trials

A banded roll is an anilox with varied engravings across the roll. The various line screens and volumes appear as bands on the anilox roll. The roll is designed to meet the needs of you, the customer. For example, the goal your company is to increase market share through improved graphics, decrease downtime due to anilox concerns and consolidate anilox inventory, one way to do this is a banded roll trial.

Improved graphics is achieved by running a thinner ink film, which requires a higher line anilox with a lower BCM . Lets say the current plate screen you are running is 150 and the anilox used for the process work is 800 line screen at a 2.1 BCM. You may determine a switch to a higher plate screen, for example, 175 lpi, this requires 1000 line 1.4 BCM. Oh but wait, is the ink going to be strong enough? You can see why it is so important to invite technical reps from the anilox, ink, plate, separations, etc., to brainstorm. Technical people are in many different production facilities and have a broad pool of experience to draw from. The fastest, most scientific way to accomplish the goal is to run a banded roll trial.

Creating a banded roll design is painless at this point because the project is defined and communicated to all involved. One important factor is to design the roll to go beyond what the team believes is the high limit. For example, the group believes a 900 line screen engraved to a 1.6 BCM is the limit to achieve the required solid ink density. For this trial, you would want a band on the banded roll at a 1200 line screen engraved to a 1.4 BCM. Remember, we want to determine at what point is the solid ink density too low. Depending upon the web width you may want to use more bands on the anilox roll and add control bands to insure parallelism. With the understanding of the banded roll design behind the group, the next step is to define the test and the remaining variables. Harper clarified the remaining variables at the 11/30/01 meeting.

Plate Material : Define the material that will be used, plate thickness, capped or uncapped, digital conventional. The plate supplier may have new processes for this application or you may want to use the plate material that you have been using for consistency purposes.

Printed Image : A test plate designed to match the bands on the anilox roll could include, 150,175 and 200 plate line screen scales to determine which anilox bands runs clean, achieves required density and target dot gain. Solid areas with positive and reverse type at the chosen font(s). Other possibilities include UPC symbols, slur / impression hexagons and vignettes.

Mounting Tape : Compare medium and soft cushion mount? Test for dot gain, contrast and solid ink density printed scales.

Inks: Verify and qualify the systems are adequate for your end use application. Test different systems for drying, color strength, dot gain, density and runability.

Remember, the more variables that are ran, the longer the test will take to run and interpret results. Stick to the plan and test what is needed, as time permits continue further testing. As far as interpreting results, get a commitment from the suppliers in the Graphic Team Meeting as to who will follow up with the reports needed for interpretation. Harper’s technical department will evaluate the process banded roll samples and issue a report. A template is also included for your use of evaluation and data collecting.

In order for the testing to be a success, it is imperative to document, document, document. In the trials I have been involved with, when the work was done up front before the trial, the trial was a success. On the other hand, trials that are set up beyond production capabilities have not been of value. The reason is simple. When setting up a trial, everyone must understand production capabilities. Before the day of the trial, we documented the above list (Anilox bcm / line screen, ink supplied, plate thickness, mounting etc.) On the day of the trial we document press speed, viscosity, pH, impression, etc. The trial goes well and all involved are on the same page, to take the next step, which would be to interpret the results. (attach copies of banded roll drawings)

Depending upon the results, we will then have the data to make a scientific determination of the line screens and volumes of your new anilox inventory. The results will also help determine the process we will take in inventory replacement. The goal is to consolidate the majority of your companies anilox inventory the potentially 3 line screens and volumes. Achieving that goal will make the replacement process more efficient.

An excellent time to verify off press proofing is during the banded roll trial for the line colors. Off press proofing of colors is another opportunity to save press time matching colors. The hand proofer, Echocel Jr., that HarperScientific manufactures is unique to industry because of the metering blade and laser engraved rolls. Most proofers today have chrome rolls with a rubber-metering roll. We have concluded that it is possible to duplicate press conditions with our system where in the past that just was not possible. For Example: on press a 400 line roll at a 3.7 BCM achieves the Lab reading desired for that particular color. Echocel Jr. will correlate very close at the same volume where a traditional proofer with a chrome roll may match at a 600 line 2.5 BCM. The opportunity is open for confusion and inconsistent color going to press. Imagine, pulling a proof for a customer request and adjusting the color off press to meet the customers desired color. Supplying the swatch with confidence, to the customer that you will be able to duplicate that exact color on press the first time on press. I will schedule our community hand proofer the day of the banded roll trials.

The banded roll is very important for verification of line screen and volume but it can not stop at this point. In order to create the Perfect World we need to now close the loop for a consistent repeatable workflow from the beginning image through to the finished product. Much of this I’m sure you are aware of so I hope this is not redundant.

Densitometric Fingerprint

After the anilox rolls are specified for process printing, we are now ready to run a Densitometric fingerprint not to be confused with a colormetric fingerprint. The Densitometric fingerprint is ran to determine the amount of press gain to form cut back curves. The new cut back curves will be applied to all files / jobs in the future. The design can include: Images, slur targets, Vignettes, Grey balance tonal blocks, graduated tonal blocks for YMCK, and trapping blocks. When running the fingerprint test remember to duplicate repeatable press conditions and match First densities.

Colormetric Fingerprint preparation

• Analyze tonal scales

Plot Dot Gain Profile

• Create cutback curve
• Apply cut back curve to the hot folder in the RIP

Assemble a Colorimetric Fingerprint

• Print contrast
• Total ink coverage
• Maximum Black

First Run targets

• DTP 41 swatch chart
• Sample images
• Output to press

Using the data from the Densitometric fingerprint now plot the dot gain curves. Based on the data create a cut back curve and applied that information to the RIP. The average cut back is 12% to 15% for Flexo not eliminating all the dot gain. (myth number 1) We are now ready to assemble the colormetric fingerprint test form and output for press.

Press (Colormetric Fingerprint)

• Run ICC profile with cut back (increase color Gamut)
• Run file on press at highest ink density (profile 1)
• Run file on press at First densities (profile 2)
• Analyze gray balance
• Measure contrast

We must insure all press conditions remained as they were in previous runs keeping in mind duplicated normal press production conditions. Then run the colormetric fingerprint test form at 2 different ink densities using the same anilox rolls to view each ink set (YMCK) strengths color gamut. Using the DTP 40 swatch chart, this includes 210 patches of spectral color data to map the color gamut of the described ink sets. Feel free to use your preference of many swatch charts available you.

Prepress

• Complete analysis of colormetric fingerprint

• Applied dot area numbers to first targets
• Ran the colormetric target on the Digital Proofer
• Analyze Digital target
• Assemble project images in RGB

• Color manage all other output devices to the target CMYK space
• Output color managed files to proof and flexo

Color management has come a long way in the past few years, as I’m sure you are aware of. The success achieved with proper color management is becoming more prevalent in successful flexo print shops that have a grasp on the entire process. Advantage of having the job come to press and matching the digital / analog proof that the customer signed off is achievable when utilizing color management and running by the numbers determined in the fingerprint process.

Good Pressroom Practices

Assuming all the prior procedures / steps are taken the last phase, is incorporating proper pressroom practices as it relates to reduction of downtime due to color variation. Good pressroom practices are needed to ensure consistency from job to job. Areas to evaluate.

• Daily check and use of Densitometers

• Anilox identification system
• Job history information

An integral part is control targets and must be included on all production images of the film negative and plate. Positioning is determined by customer requirements, trim waste and job layout according to slitting or die cutting. Control targets are necessary for measuring print characteristics at set-up and throughout the run. Compare and adjust the control target measurement data to the press characterization. I have the control targets on a floppy disc for use if needed. Some of the information needed on the control target include, reference code #, tonal scale including dot gain values, solid ink patches including density values, highlight gray balance scales, shadow gray balance scales. The control targets are scientific tools the press operators use to ensure consistency through printing by the numbers. Determine the time between each check if it is every roll change or every hour. Sign off on and record time of all reading and retain samples for evaluation at a latter date. All the numbers come from the Densitometric / colormetric fingerprint.

Job History or production specifications must be completed and supplied with each run. The job history at you company covers what is needed with exception to ink viscosity and density through out run. During the visit a few weeks ago, it was noted that some of the Job history sheets had complete information and others did not. Retrain all personnel for reasoning and proper use of Production Specifications.

Preflight/in-process checklist is a critical factor to insure the upcoming job is in order. Possible additions to check off would include, doctor blade changes, impression cylinders cleaned including time and deck number.

pH / Viscosity Monitoring sheet is a part of the paperwork in the pressroom. You must supply all the tools needed to consistently repeat production runs without over complicating the operators. We need to look at all paperwork needed through the press operators eyes and determine what we can consolidate, modify, or eliminate.

I must stress that we at Harper are very concerned with this particular problem and support your company and their efforts in trying to find a logical solutions to minimize downtime, waste and color variation due to the anilox roll. The above issues are in fact negatively impacting the life of the anilox roll. In order to correct the concerns we need your cooperation.

To summarize, Harper Corporation appreciates your business and will do whatever we can to incorporate the above opportunities. Thank you for the opportunity to put into practice all the tools we at Harper believe in. If you have any questions please feel free to contact me at 800-627-4784, Ext. 104. Otherwise, I look forward to meeting with you in the near future.

Best Regards,

David L. Brewer
National Technical Coordinator
Harper Corporation of America
DePere, WI

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