- January 31, 2006, Edward D. Cohen, Edward D. Cohen Consulting
What to do with an aging coater is a dilemma encountered by many people in the converting industry. As the coater matures, it will start to develop problems that will affect its operating efficiency and profitability.
Coating quality can decline and yield losses increase. As the coater wears out, it becomes harder to maintain and operate. It may not meet requirements for manufacturing new products, and financial performance is less than optimum. Other factors are the need for additional manufacturing capacity to meet sales requirements and competitors utilizing new technology to produce a superior product.
Therefore, at some time in the coater life cycle, a decision needs to be made as to its future. A viable alternative is to modernize the coater. The coating process is modular, and it is possible to replace and upgrade selected process components effectively or to add new functions. Modernization can improve coater productivity, quality level, and profitability at a relatively low cost, and efficiency can be maintained for years with ongoing upgrades. It is also an alternative to investing in a new facility.
In an effort to gain insight into whether modernization is being used, a survey was conducted on the age of coaters in various companies. These results, summarized in Table I, reveal the average age of production coaters is 18 years, with some as old as 30–50 years. These results indicate modernization is being used and is very effective. It is hard to conceive of a 30- or 50-year-old coater being competitive without having been upgraded several times.
One concern with modernizing is that at some point the coater may not be worth saving because it has too many flaws. It also requires an ongoing commitment; one upgrade in ten years will not be effective in maintaining coater efficiency.
The decision as to which coater elements to modernize depends on several local factors, and each situation needs to be analyzed separately.
Identifying Process Deficiencies
The first step in the decisionmaking is to analyze the current coating process to identify areas that are limiting or deficient. This is needed whether a new coater is to be built or a current one modernized. If this is not done, the new coater may be built with the same flaws as the existing coater and will not have modern technology. It will be a new copy of the old design.
The goal of this step is to identify all the requirements needed so they are met. At this stage, the analysis should be on needs, and the technical feasibility should not be discussed.
There are several sources of deficiencies should be analyzed to ensure all needs are identified. The quality control records and yield loss data will identify major types of loss such as chatter, mottle, streaks, heavy edges, contamination, out-of-specification coating weight, ribbing, poor winding, etc. Using coater operational logs will aid in identifying productivity, unplanned downtime, and equipment operational problems. Discussions with operating personnel will help identify deficiencies and areas of needed modernization. Input from R&D will help find deficiencies that are preventing new product development, such as the need to coat thinner substrates and coatings and the need to improve coating weight uniformity. Sales and marketing can identify customer quality concerns and future demand.
In conducting this analysis, you need to look at the basic process elements: coating, solution handling and mixing, drying, web transport, range drive, unwind, rewind, and control systems. In addition, peripheral systems such as quality control strategy, training, and product change time need to be characterized.
Losses in these later areas can be larger than realized, and improvements can be implemented easily.
When this is completed, a document should be prepared that lists the needs, deficiencies, and economic impact of each item. The economic impact can be a reduction in loss, additional capacity for which earnings can be calculated, or earnings from new products.
A priority should be assigned to each item. For example, if a critical part is close to failure and there are no replacements, such as in a very old drive, this would have a high priority. Table I is an example of the type of data that can be generated.
Identify Available Technology
The goal of this step is to determine the currently available coater hardware, technology, process instruments, and analytical instruments. This will permit the selection of the appropriate technology to correct the deficiency.
There are several sources for this information, including trade journals and vendor Web sites. Searching the Internet also can identify new technology. Technical meetings are a good source of information and are offered by many industry organizations.
Table II summarizes some of the upgrade technologies.
|Examples of Coater Deficencies|
|Chatter||19.7 M sq. ft.||$2,358,720|
|Out of spec coating wt||32.7 M sq. ft.||$3,931,200|
|Heavy edges||14.4 M sq. ft.||$1,729,728|
|Drying capacity||45.8 M sq. ft.||$5,503,680|
|Customer defect returns||32.7 M sq. ft.||$3,931,200|
|Thinner coating wt||60.0 M sq. ft.||$12,000,000||New business|
|Availability loss||65.5 M sq. ft.||$7,862,400||Operational|
|*Scrap material savings=$0.10/sq. ft., New Business=$0.20/sq. ft.|
Determine Corrective Action
The next step is to determine the corrective action for each of the identified deficiencies or needs; this involves understanding the cause of the defect and identifying the technology or hardware that will correct the problem. Then the cost of the cure and the economic return can be calculated. When this is complete, a decision on how to proceed can be made. A helpful method is to develop a cause-and-effect (or fishbone) diagram.
Relatively inexpensive modifications often can have a major impact. Also, an analysis may show that several deficiencies can be corrected by one upgrade. In the example in Table I, the chatter, out-of-spec coating weight, and need for thinner coatings are three different problems, but all suggest the need for a new coating applicator.
|Coater Age in Years|
One typical deficiency encountered is that the existing coating method is inadequate and several new coating methods are needed. The recent availability of cartridges coaters allows rapid coating head changes and routine use of multiple coating methods.
Implementing the Program
After you have identified the deficiencies and corrective actions needed, evaluate the action items for economic return, technical feasibility, and downtime to install and accomplish the upgrade. The upgrade costs need to be established as part of this analysis. The cost of the downtime must be included, in addition to the hardware and installation cost.
|Available Upgrade Technologies|
|Dryers||High rate impingment
Heating & ventilating systems
|Coating station upgrades||New coating methods (Slot die, Curtain)
Multiple coating method stations (Cartridge coaters)
Precision-instrumented coating station
|Web handling system||Solid-state range drive
Winders & unwind
Wide range tension control
Additional support & drive rolls
|Online instrumentation||Defect inspection vision systems
Coating weight (thickness) measurement
Viscometers to continuously coating solutions
|Substrate surface treatment||Flame
Atmospheric plasma, flame, corona
Surface contamination cleaning
|Process control instrumentation|
|Information management systems||Data logging & analysis
Standard procedure development & maintenance
|Quality control strategy||Test methods & defect characterization
Systems SPC, ISO, 6-sigma
A budget-planning estimate with an accuracy of 30% is adequate for this analysis. However, this should be verified after the final construction project is prepared. Once the analysis is done, upgrades should be selected and construction projects prepared.
When selecting upgrades, the highest economic return does not need to be selected. It is often better to select two intermediate items that can be accomplished rapidly with a high probability of success than one with more risk that may take longer to implement.The vendor for hardware should be considered a partner in the project to help ensure success.
In addition to major projects, routine coater maintenance can modernize a facility. For example, when replacing hardware, choose an upgrade rather than simply replacing in kind.
Modernizing a coater offers the following advantages:
- Permits focus on high-return items
- Allows installation of low-cost upgrades with major impact
- Matches capacity increases more closely with sales growth
- Utilizes new technology as it is available
- Makes it easier to match project work with company capabilities
- Makes it easier to utilize outside resources
- Requires less capital, which is spent in manageable increments
- Gives a competitive advantage
Edward D. Cohen is a technical consultant for AIMCAL, the Assn. of Industrial Metallizers, Coaters & Laminators. He has 40+ years of experience in research and manufacturing technology. Contact him at 480/836-9452.
This article, along with future articles by other authors, is provided as a cooperative effort between PFFC and AIMCAL. Authors contribute to AIMCAL's technical and education offferings, which include the association's Fall Technical Conference, Summer School, and Ask AIMCAL.
The views and opinions expressed in Technical Reports are those of the author(s), not those of the editors of PFFC. Please address comments to author(s).