New profiles, materials, processes and technology define todayâs profile wrapping operation.
|Improvements in materials and technology have helped to improve the productivity and flexibility of profile wrappers. Photo courtesy of Nordson Corp.|
Profile wrapping has come a long way, from the early days of applying overlays to simple moulded edges, to wrapping complex shapes with almost limitless materials today.
According to Elizabeth Jordan, senior program manager for Nordson Corp., profile wrapping has evolved greatly due to a variety of events shaping the technology.
âProfile wrapping started using cold glues applied to a paper or veneer by a roll coater and involved rather simple millwork shapes with few surface changes,â she said. âHowever, every aspect of profile wrapping has seen great technology leaps in the past decade or two. Profile wrapping now utilizes numerous materials, including vinyl as well as traditional paper or veneer. Profiles now encompass not only wood or engineered wood products, but a wide variety of plastics and aluminum. The glue has progressed, from solvent-based cold glues to hot melt adhesives, including ethylene vinyl acetate (EVA) and polyolefin, and now reactive polyurethanes (PUR). The adhesive application/coating technology has also evolved, from a basic roller system to hot melt rollers to a closed slot nozzle coating system.â
Jordan says the changes were driven by many factors. âObviously, end products have changed, but there have been changes in government regulations. Changes that have had to be addressed by both materials and manufacturing technology include: appearance, durability and component/material changes [adhesive, profile substrate and wrap].â
According to John Van Brussel, vice president of Veneer Systems Inc., the most popular applications for profile wrapping are: baseboards, picture frames, flat pieces, coffins, kitchen cabinets and bull noses.
âThe veneer usually has a backing paper [typically 5 mil kraft paper] or 30 gram fleece [non-woven cellulose]. Veneer can also be fingerjointed to make long rolls of veneer. Additionally, this veneer can be color and grain matched, making the fingerjoint virtually impossible,â Van Brussel says.
The veneer is sanded after fingerjointing and the backing is applied, making it very pliable and supple. âFor more complex profiles, the backed veneer can be flexed using a veneer flexer,â Van Brussel explains. âThe veneers are then passed through a machine, which has a large diameter rubber roller and a small diameter stainless rod. This process is repeated again after flipping the veneer over. The end result is a very supple and pliable veneer, while the backer keeps the structural integrity of the wood intact during the flexing process,â he adds.
This flexibility is very important, says Larry Ackernecht, president of Voorwood Machinery. âThe variety and scope of profiles is one area of tremendous change, from the types of shapes that can be wrapped, to the materials used and the end products. Shapes go from plain to fancy, small to big â every kind of geometry. Customers can get plastic, wood grains, solids, patterns, pretty much anything they want. There is real flexibility in what the customers can do and what they can do it with, from veneers, to vinyls, to papers, and polyester,â Ackernecht says.
Matt Fish, general manager of SourceCut Industries Inc., agrees that the possibilities for profile wrapping are almost endless. âRounded curves are just the tip of the iceberg when it comes to wrapping capabilities. What can be profile wrapped is limited [only by the] imagination. Typically, anything that can be run in lineal lengths can be molded. Traditionally, anything that can be molded, shaped or profiled can be profile wrapped. Not only are we flexible with the type of profile that we can wrap, we are also flexible with the substrate upon which we are wrapping [from wood to metal], along with the type of material that we can wrap with [from paper to fur],â Fish says.
âItâs [also can be considered] a green product in the sense that the wrapped [substrate] can be fingerjointed from smaller pieces,â Ackernecht says.
Occupying the High End
While originally profile wrapping might have been considered a lower-quality alternative to real wood products, that is no longer the case, according to those interviewed.
âThe simple trimwork and furniture designs that originally used profile wrapping have been expanded to include more intricate trimwork as well as high-end furniture, and now even complete windows, including interior and exterior exposure,â says Jordan. âThe current expectation is that profile-wrapped pieces have a high quality appearance that will hold up over time. Previously, profile wrapping was used only in household interiors, but the trend is to now include exterior products that must stand up to harsher conditions of extreme high and low temperature, as well as moisture and sun exposure.â
According to Jordan, these new applications have made critical the ability to control adhesive application. âThere is a need for a thorough coating for complete adhesion of the wrapper to the profile. Adhesive coating voids caused by either contamination or incomplete coating coverage can cause the wrap and substrate to delaminate over time. At the same time, over-application of the adhesive can result in both a poor bond between the wrap and the substrate as well as appearance issues. Excess adhesive can squeeze out of the edges of the finished products, resulting in either the need for excessive clean-up or an unsightly finished product,â she said.
Custom or Production?
Although originally designed for high-production environments, the general consensus is that todayâs profile wrapping equipment makes the application suitable for both high-production as well as custom applications.
âWhile much profile wrapping is [still] production rather than custom, the ability to achieve shorter changeovers via integrated systems and tighter process controls allows for the more cost-effective production of shorter runs than these production environments were able to achieve in the past,â Jordan says.
Profile wrapping is suitable for both types of production arenas, agrees Fish. âProfile wrappers are a piece of machinery. Whether or not you apply them to long-run, dedicated production parts or to custom manufacturing is a matter of the market you want to serve. Profile wrappers can serve either purpose,â he says.
âIt is usually used for high volume production, but I think in todayâs marketplace, there is more and more custom work being done using a variety of different types of glue, although the most common used today are EVA hot melts and PUR,â Van Brussel adds.
Regulations & Durability Issues Spur Change
âAdhesive changes have resulted from both government regulation as well as durability issues,â Jordan says. âTwenty or 25 years ago, the government started reviewing and reducing VOC emissions from solvent-based products such as adhesives and paints, so composition and use of all solvent-based products had to be evaluated and if necessary, changed.
âThis resulted in a switch from cold glue, solvent adhesives to solvent-less hot melt adhesives,â Jordan adds. âWhile the roll coat processes used for cold glues and hot melt adhesives are similar, obviously, the system components had to change in order to handle hot melts. First of all, instead of just a pot of cold adhesive, there had to be a melter involved to melt the adhesives, and the pot had to be heated or fed molten adhesive from the melter at a steady, continuous rate. And the materials used to make the actual rollers have also had to adapt to handle hot melt adhesives, rather than cold.
âThe introduction of reactive PUR hot melt adhesives has required an additional change to equipment. As the PUR reacts to moisture, such as that found in the air, it is important to operate a closed adhesive system that keeps the PUR from being exposed to air,â she continues.
Unlike with the adhesives, the reasons driving the material changes are varied. One reason in particular is that the use of substrates other than wood or wood-based materials, such as plastics or metal, has led to the forming and wrapping of more intricate and complex profiled parts.
â[For example,] use of aluminum in window manufacturing is prevalent, so with an increasing need to improve the appearance of finished windows, profile wrapping comes into play,â Jordan says. And, she adds, â[While] the wrap itself used to be simple paper or veneer â both still commonly used â the use of vinyls has become more prevalent. [Plastic] films have the ability to withstand the harsher external environments and real wood has the ability to be painted or stained.
âThe ability to be versatile in what material is being coated is an equipment need,â Jordan says. âThe equipment has to be able to accommodate the wide range of wrappers, substrates and adhesives....it has evolved into a sophisticated process that tightly controls such key elements as: exposure to airborne contaminants, optimizing the coating width and thickness, and maintaining the adhesive/process temperature.â
The evolution in machine technology also has been driven by the need of woodworking manufacturers to maximize production efficiency and minimize waste in order to be competitive in the marketplace.
âThe ever-increasing use of closed systems allows machinery to be used more efficiently, with less time needed for changeover of jobs and maintenance such as cleanup,â Jordan says. âThis not only allows manufacturers to increase production while using existing systems, but also reduces labor. And, as scrutiny of finished goods is getting tighter and tighter, the ability to produce consistent product from the first piece to the last reduces rework and scrap,â she adds.
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