For a number of reasons, the ability to use prepainted coil to improve productivity and to reduce costs may provide a competitive edge to survive in an increasingly competitive manufacturing marketplace.

Almost every manufacturer in business today relies on coatings to make their products. Towards this end, they are faced with the choice of applying the coating to a finished part (post-painting), or producing their product from metal coils that have been already painted (prepainting).

Improvements in metallurgy and tooling, paralleled by developments in paint technology, have led to the increased popularity of precoated coil products. New ultra-flexible paints and vinyl laminates have been formulated that are decorative, may be applied over a variety of substrates, and adhere tenaciously to roll formed or stamped surfaces.

For example, polyesters, epoxies, acrylics, kynars and vinyl laminate may be applied to a variety of substrates including stainless steel, cold rolled steel, galvanized and electro-galvanized steel, aluminum, tin plate, black plate, copper and brass. Manageable thicknesses range from 0.006 in. to 0.048 in. for steel, and 0.008 in. to 0.060 in. for aluminum.

Clearly, prepainted metal is not suitable for every manufacturing application. In many cases, post-painting remains the only option. But with significant savings to be had by switching to prepainted metal coils in certain applications, why haven't more manufacturers taken advantage of this option?

Improvements  in metallurgy and tooling, paralleled  by developments in paint technology,  have led to the increased popularity of precoated coil products.

Manufacturers entertaining a change to prepainted metals often lack the tools to adequately evaluate the benefits of prepaint vs. post- painting. To consider such a change, manufacturers must balance the costs associated with retooling to handle prepainted metal coils, against the increased productivity and long-term savings obtained by the removal of all or part of the post-paint operation.

"Coil coating has many definite strengths," says Don Coulson of Coulson Metal Forming, a company that designs and builds roll forming equipment for manufacturers. "The quality of the coatings is magnificent, prepainting allows incredible line speeds and the product is ready to be used as soon as it comes from the roller."

Coulson points to one of his customers, Three Day Blinds, as an example. "Traditionally, the head rail for mini blinds was made of extruded aluminum. But we designed equipment to make the head rail out of prepainted, roll formed steel. Instead of buying truckloads of long extrusions, cutting them to length, punching holes, preparing and painting them, we did it all on-line so they came out finished parts."

The use of prepainted metal coils reduces expenses associated with in-house painting equipment and labor, hazardous waste disposal, compliance with EPA regulations, and maintenance of emissions equipment and permits.

According to the National Coil Coaters Association, "With more than 30 percent of the manufacturing maintenance budget and plant capital expenditures being spent on growing environmental compliances with ever more strict EPA regulations, the need to reduce these and other operational costs is paramount to survival."

Making parts from prepainted metal also can help reduce inventory and space requirements because they are immediately ready for shipment or assembly. By removing the entire post-painting operation, the newly created space on the factory floor can be used to house additional production machinery to increase capacity.

"Assuming the elimination of post-paint materials and operations, the cost benefit realized by converting from post-painting to prepaint will typically be between 10 percent and 60 percent depending on the approach used, the depth of analysis and the size of the operation."
-- National Coil Coaters Association

Production also can be increased by eliminating the bottleneck that post-painting imposes on the manufacturing process. The time and labor required to paint, cure, inspect, touch up and reinspect often limit production. By removing these steps, product flows can be generated that are more efficient--decreasing unit costs.

"There are a number of products that require secondary or tertiary operations after they are manufactured, before they go through the painting process." Coulson explains, "You could replace a lot of these processes with a finished part right off the machine by using prepainted coil."

Prepainting is typically contracted to coil coating companies such as Western Metal Decorating, Cucamonga, CA. A provider of prepainted coiled steel products since 1963, they specialize in small custom paint runs and vinyl lamination.

"It used to be that parts were painted after they were cut, shaped and formed," says Scott Brotzman, president of Western Metal Decorating. "However, handling and painting one part at a time is very expensive. Prepainting is much more cost effective because we can paint large quantities very fast. As long as the application is correct, prepainted coil often can be made into the same parts that were previously being postpainted."

At Western Metal Decorating, coils weighing up to 20,000 lbs. and 48 in. wide are slit into widths that can be processed through the coating line. Next, the material is cleaned using cleaner with a high- pressure water spray. The cleaned surface is chemically treated to improve adhesion and inhibit corrosion. Then the manufacturer's specified coating is applied to one or both sides and the newly coated steel is cooled and recoiled.

The painted coil is final slit to the customer's specifications so it can be stamped, deep drawn or roll formed into products like towel racks, picture frames, door jams, lighting fixtures, mini blinds or domed lighting. The ability to slit material to the manufacturer's exact width requirements lowers costs by reducing waste disposal, increasing yield and eliminating an additional step in the manufacturing process.

Western Metal Decorating offers value-added services such as assisting manufacturers in the specification, purchase and storage of coiled steel and custom slitting, palletizing and shipping. If required, one or two week turnaround times can be achieved.

The success of a coating depends on three factors: The coating must be physically capable of withstanding its intended use, its application quality and surface preparation must be assured, and it must be able to withstand the manufacturing process.

To confirm the quality and suitability of a coating for a given application coil coaters can administer a series of physical tests, including forward and reverse impact, film weight, tape pull and solubility tests.

Along with physical tests, color quality and consistency is computer verified on-line. This allows custom paint runs in quantities tailored to meet the material requirements of small manufacturers.

The ability to color match in small quantities has proven invaluable for Channelume/Let-R-Edge Co., a manufacturer of metal components used in the electric sign industry to construct channel letters. Their signs consist of individual channel letters that are machine rolled and hand formed from precoated aluminum coil to represent company logos.

"Western is one of the few companies in North America that will produce the small quantities we need for each of the 20 or more colors we use in our process," says Channelume's David Servine, "They even can match the specific colors required for corporate logos."

The flexibility and quality of preapplied decorative coatings and vinyl laminates has stimulated industry to use metal in place of wood, plastics and other traditional materials. Wood, long prized for its strength, warmth and beauty, has enjoyed the broadest utilization of any material for construction and decorative applications. However, environmental concerns, conservation efforts, and the increasing cost and rarity of fine grade wood products is driving manufacturers to turn to coated metals.

To simulate natural materials such as wood grain, a vinyl laminate can be applied to metal coils. The process is similar to painting, except adhesive is used. The bond is permanent and the laminated coil can be formed, drilled, stamped or punched into many shapes. Pebble grain, linen texture, leather texture and freeform pattern laminates also may be applied to metal coils to make anything from VCR covers to medicine cabinets.

However, finding a coil coater that applies vinyl laminate may be difficult. According to Brotzman, Western Metal Decorating is the only company on the west coast capable of vinyl lamination from 4 mils to 12 mils thick over cold rolled steel, aluminum or electrogalvanized steel.

"We also can reduce costs and increase the production rates of our customers by applying laminates to both sides of the coil at the same time," says Brotzman.

Vinyl laminate proved a cost effective and practical solution for WonDoor, a company that manufactures accordion-style room dividers and acoustical doors for high-rise buildings, schools, offices, churches and casinos. Thirty-six years ago, most of WonDoor's products were made from extruded aluminum panels. In the late 70s, the increased cost of aluminum and the necessity to meet fire safety requirements compelled them to try vinyl-laminated coiled steel.

"When you send precoated steel through the roll forming process it becomes quite unique and attractive," says Craig Bell, operations manager of WonDoor. "It's certainly better than the alternative used by a majority of our competition, which is constructed with wood or a different type of vinyl."

"The capital cost of new tooling for roll forming may be higher than extrusion dies, but when you're talking high volume, it doesn't take too long before it's justifiable," continued Bell.

"The best advantage of coil coating is it's a whole lot less expensive than a secondary operation (post painting)." MF