Refined flatline automation leads to higher productivity, savings.

Automated finishing equipment offers precise application and helps manufacturers comply with finishing regulations.

What is the most significant, recent development in wood finishing automation? According to finishing equipment manufacturers surveyed by WOOD & WOOD PRODUCTS, one standout is the refinement of conventional flatline application processes. This includes automated reciprocating, carousel/rotary spray systems and roll coaters.

"Automatic (reciprocating) equipment permits the application of coatings with close scrutiny over all variables, resulting in the most economical and highest quality results possible," said Tony Stranges, finishing systems division manager for Stiles Machinery Inc. "The development and use of precision equipment provides the opportunity to more economically utilize compliance-type coatings such as UV and waterbased, while maintaining acceptable production requirements," he added.

Reciprocating systems gaining in use

Reciprocating systems are among the newest technologies to hit flatline finishing, said Stranges. Advantages of both reciprocating and carousel/rotary style systems include the following:

* Allows for the application of more coating on the product surface.

* Edges and tops can be finished in one pass, including bullnose, profiles and mouldings.

* Workpieces do not have to be calibrated to close tolerances in order to be coated; warped boards can be finished evenly.

Although not as transfer efficient as roll coaters, reciprocating and rotary systems can now be equipped with overspray recovery systems. Stranges cited the Cefla EcoSpray machines' use of a solid mylar belt for material recovery as an example of this recent technology.

"(Rotary and reciprocating) flatline technology allows for recovery of material, high transfer efficiency, improved quality and less personnel, which leads to higher profits," said Bob Hereford of Rhodes Systems. "It is my feeling that a trend toward flatline finishing will be more popular in the future."

Glen Muir, paint and coatings equipment/technical specialist at Graco, echoed Hereford's assessment of flatline's future. "I believe flatline type spraying in contained booth enclosures will come back in a year or so because of the current unsettled state of the materials market," Muir said.

Roll coating

Although roll coaters are not as effective on raised panel doors, or other items with routed or trimmed recesses, they do offer other advantages, Stranges said. These include increased feed speeds ranging from 50 to 100 feet per minute, versus a typical 18 to 30 feet per minute for other flatline spray systems, and approximately 98 percent transfer efficiency.

Currently, roll coating is a specified, approved method of transfer efficiency in at least six states or regions, including: Indiana, Michigan, Ohio, New Jersey, Illinois and Southern California.

"From our point of view," said Don Jones of Black Bros., "we believe the development of 100 percent solids, UV curable finishing materials that can be applied in roll coaters onto flat surfaces, is very significant."

Equipment needs change with waterbase usage

Waterbased finishes are currently the top choice of environmental agencies in reducing finishing emissions. Of the nine possible RACT (Reasonably Available Control Technology) VOC-reduction options under determination by the U.S. Environmental Protection Agency, number one is a full waterborne system, followed by a switch to a hybrid waterborne system. (See W&WP, May 1992) A hybrid waterborne system uses a combination of both waterborne and conventional solventborne coatings, such as solventborne stains and washcoat used in conjunction with a waterborne sealer and topcoat.

In order to facilitate the switch to waterbased finishes, material suppliers will have to work closely with their customers to educate and train workers on revised application methods, said Jones.

Tom Ellis of Classic Systems said, "I think a combination of waterbased and solvent formulations will be used. This combination would help meet the new standards for VOC emissions and at the same time allow furniture manufacturers to finish their furniture with the more traditional and accepted finishes.

"Most furniture manufacturers are experimenting now with some type of hybrid finish. But keep in mind that the switch to a waterbased formulation finish requires a substantial change in the finishing system itself, requiring heated flash or preheat and a longer drying time." One example of new technology designed to help industry comply with the Clean Air Act amendments is the CamBooth spray booth, Ellis said. Through the use of an air curtain, air makeup, horsepower and cfm requirements are reduced and increased transfer efficiency is achieved, he added.

Paul Smith of Fuji Industrial Spray Equipment, noted some of the equipment changes his company has developed in order to achieve an aesthetically pleasing appearance using waterbase finishes.

"We have developed two special nozzles with six extra atomization holes for use with these products," he said.

"Finishing equipment will have to go to all stainless steel tubing (SST) wetted (304 or better) and piping and pumping will also have to become SST," said Muir. "The atomizers will have to deal with harder-to-atomize materials. HVLP will stay relegated to stains and color and air-assisted will again resurface as having adequate energy to atomize these new materials. Typical air-assist pressures will approach 3,000 psi to atomize the new coatings adequately."

"Automated finishing equipment presently in use, such as roll coaters, curtain coaters and automatic spray machines are already equipped for use and application of waterbased formulations," said Stranges. However, he added, "I do not believe waterbased formulations will be the dominant wood products finishing material used by the end of the decade. Rather, I think they will share that honor with UV-type coatings. Presently, UV-type coatings provide superior physical and chemical properties and a more appealing finish. Film build, flash and curing requirements are also advantages to consider. However, waterbased coatings will undoubtedly be improved at a much faster rate."

Compatible equipment

The following is some of the equipment available which can be used with waterbased, UV or hybrid systems. For more information, circle the corresponding number on the Reader's Service Card.