While the answer to the question can be stated rather simplistically, a more in-depth look can often reveal costs not found on invoices or traditional cost models. These hidden costs, if not understood and quantified, will quickly differentiate electrocoat operations in terms of operational expenses. Additionally, these costs will erode the "lower total applied cost " advantage that is often assumed by electrocoat OEM manufacturers and job shops. Finally, these costs are not always expressed in dollars by the end user but are more often accepted as "system limitations."

The Cost of Electrocoating: Why Define Cost?
Detailed operation models are often employed during the design and selection process of any finishing system. While models provide an excellent guideline, operational costs need to be quantified once the finishing system is running under normal production conditions. Defining the "actual " cost of your finishing system--

• Establishes a cost baseline for your entire finishing system;
• Identifies costs for each component of your finishing system; and
• Exposes inefficiencies.

Calculating Cost
In general terms, the cost of electrocoating is often discussed in terms of "cost per square foot. " This description is not very specific and sometimes misleading when discussing electrocoating costs. When calculating the cost for electrocoating systems, two specific labels should be employed: 1) Material cost per square foot and 2) Total cost per square foot. The total cost per square has three main components:

• Operations Costs,
• Human Resources, and
• Material Costs.

Operational costs include utilities such water, electricity, gas, consumables, and routine maintenance. Variations in operational costs are mainly dictated by geographic location and the size of your electrocoating system. Operational costs are frequently targeted in cost reduction programs at many OEMs and job shops. Unfortunately, unless there are gross inefficiencies in the process, no major savings are usually realized in this area. For example, natural gas consumption is often targeted through reducing oven temperature. Careful evaluation of natural gas expenses relative to an entire operation reveals a savings that is often minimal. More significant savings can be realized by choosing a material that allows dense part packing, increased line speeds, and uniform film build.

Human resources are costs incurred through compensation of electrocoat operators or others directly related to the operation (e.g. pretreatment). This cost is most significant when comparing coating technologies. For example, an electrocoating operation may be able to double or triple its throughput before needing to add any additional operators. Comparatively, a powder or liquid line with identical increases in throughput typically requires the addition of manpower in an almost a linear fashion. Human resource differences between electrocoat operations are dictated by the system size and material efficiency.

Finally, material costs include paint, pretreatment chemicals, additives, solvents, and material efficiencies. Of these costs, material efficiency is probably the most commonly overlooked and underestimated, especially when trying to calculate the "total " cost of a material.

Calculating Material Efficiency Costs
Material efficiency is a complex cost term that must take into account operational factors, including transfer efficiency, performance capabilities, throwing power, and material shrinkage. At this point, two low-impact assumptions can be made for calculating material efficiency.

• Transfer efficiency differences are negligible when comparing different electrocoat materials. This term only needs to be included when comparing different coating technologies.
• When calculating material efficiency for two products, it is always assumed that both materials meet or exceed the performance requirements.

The "modified" material efficiency model now includes material shrinkage and throwing power. Additionally, cure oven temperature can be added to the material efficiency model to investigate its impact when comparing products.

Shrinkage is the amount of deposited film lost during the cure cycle and is directly related to the cure temperature of the coating. A second important characteristic of shrinkage when calculating material efficiency is that once it is quantified, it becomes a constant in your cost calculation. All electrocoating operations should determine the shrink value for their operation if they want to ensure accurate cost calculations.

The final and most often overlooked factor in material efficiency calculations is the "throwing power effect " on material efficiency. Throwing power is best described as the ability of a coating to build a uniform film across a single part or rack of parts as they pass through the electrocoat tank. For a material efficiency study, the throwing power effect is used to describe the inability of a coating to deposit film evenly over racked parts. In order to achieve the necessary film build on parts in the center of the rack, excess film must be deposited on the parts nearest the electrodes. To overcome the throwing power effect, an electrocoat product should begin to "shut down " as film builds. On a system with dense part concentration, shut down allows the film to build on parts on the inside of the rack after parts on the outside rack have been coated to near optimum film build.

Table1. Electrocoat Operation Parameters
Technology:	Cathodic Epoxy
System Design:	Conveyor
Line Speed:	20 fpm
Operation Time:	8 hours per day/250 days per year
Throughput:	20,000,000 sq ft per year
Film Build:	0.6 mil target film build

To quantify the throwing power effect on an existing system, the film thickness of parts should be monitored during periods of heavy line loading. Depending on the severity of the effect, film builds may vary as much as 0.5 mils when comparing outside and inside racked parts. The "film gradient " across your racks must be included in cost calculations in terms of excess paint volume deposited per square foot. While the throwing power effect will not prohibit you from racking your line densely, excess paint deposition on parts drastically decreases material efficiency. Frequently, this excess paint deposition is accepted as part of the finishing process and not factored into the total operations costs.

Consider the electrocoat operation described in Table 1. If this operation experiences the "throwing power effect, " what are the implications?

• Accept the loss as a finishing system cost (not likely acceptable in competitive market);
• Slow the line down and run at lower voltages ((decreases throughput per day); or
• Increase operation hours each day (increases operations costs and effectively reduces throughput).

It should be noted that none of the above options is a "silver bullet " for excess film deposition. Additionally, if an operation wishes to increase its throughput, the throwing power effect will be magnified as the part density and/or line speed increases.

There are many factors that contribute the cost of an electrocoating operation, and it is important to clearly understand all of these costs to maximize efficiency in an increasingly competitive marketplace. It is also important for end-users to evaluate their cost programs closely and on a regular basis to insure that they are minimizing their total system cost per square foot and maximizing their productivity. Finally, these regular evaluations of your total system costs (on a square foot basis) insure that your cost reduction programs are focusing on the most inefficient areas of your operation.