Straight On Through
Five industry experts discuss new developments and trends in straight-line edgebanding.
Feed a part through one end of the woodworking machine and a few seconds later retrieve a banded piece from the other. If it is a single-sided edgebander, and odds are it is, simply turn the workpiece 90 degrees to repeat the process to an adjacent edge or 180 degrees to treat the opposing edge.
Between the infeed and the outfeed of even the most basic straight-line edgebander, though, a lot of carefully orchestrated operations take place. First is the feed track system that holds the part firmly in place at the same time it conveys it through the machine at anywhere from 30 feet per minute to three, four or more times faster. After glue is evenly applied to the edge of the substrate, the part travels into a pressure zone, where the edgebanding material is pressed against the glued edge. Next up is flush end trimming of the edgeband, which is immediately followed by top and bottom bevel trimming.
There are a variety of options from which wood products manufacturers can choose to upgrade a straight-line edgebander beyond entry level to meet specific product requirements. David Lillard, product manager for Delmac Machinery Group of Greensboro, NC, says some of the most popular add-ons include:
Getting in Synch
The more operating stations an edgebander has, the greater the challenge and time required to properly adjust individual machine settings to accommodate varying part thickness, edgebanding material thickness, etc.
"Current buyers are looking for machines that are easy to operate and will ensure a high-quality finished product with low-skilled labor," says Rick Hannigan, vice president of sales for Holz-Her U.S. of Charlotte, NC. "Due to their need to be more flexible and responsive to the market, they are buying machines that can be changed quickly and easily from one product to another. This requires a significant reduction in the number of manual adjustments that must be made by the operator. New advanced control systems and automation are high on the wish-list for current buyers."
Performed manually, the sum total of adjusting the stations of an edgebander can be very time-consuming, taking a half hour or more plus the expense of several test pieces to get feed speed, tool angles and other critical machine functions in synch with one another.
The digital age has proved to be a godsend for edgebanding operators in helping reduce setup for a programmed part to mere minutes, according to Sermonet, Hannigan and others interviewed for this article.
"One of the most significant improvements in edgebanders has got to be the controller with color monitors," Sermonet says. "The labor skill level on the shop floor today is not what it once was, so woodworking companies must have a machine that is easy to operate and is able to go from edging one type of part to another more quickly."
Sermonet says that up to a little more than a decade ago, only high-end edgebanders were equipped with controllers. "The same goes for corner rounding and pre-milling. Now, digital controllers are standard, and corner rounding and pre-milling stations are frequently sold even on our entry-level banders."
The digital readout settings that can be stored in the controller dramatically reduce the time it takes to calibrate an edgebander's setup when changing from one part to another. All the operator has to do is adjust settings on key components of the edgebander, such as the rake angle of the cutting tool for top and bottom trimming, to the corresponding digital readout. In addition to helping take the guesswork out of tool positioning, Sermonet says controllers help end-users collect statistical data, including tracking the amount of panels fed through the machine and valuable information for adhering to maintenance schedules. "The interest in this segment of the market has increased considerably," he says.
Stepping up to Servo Motors
While digital readouts are a time saver, the ultimate, but more costly method of changing over an edgebander's setup is accomplished by instructions sent from a computer to a series of servo motors mounted to the individual workstations.
"Computerization has become an integral part of a successful, growing, profitable woodworking business," Hannigan says. "Edgebander buyers are demanding quick setup and fast changeover. They are no longer willing to spend a long time with the safety hoods open, making manual adjustments to working units to change from one edgeband type to another.
"The very latest technology features computer-controlled adjustments for virtually every spindle that the operator might need to adjust. This includes the magazine, pressure unit, end trim, top and bottom trim, scraping and other more complex units. Servo motors are attached to the spindles and are able to make very fine adjustments to within 0.001 inch within seconds. These are metalworking tolerances and much more accurate than an operator can do manually, even with digital counters," he adds.
"The big push for us in the future is adding servo motors on entry-level machines," Semonet says. "With them, the intervention on the part of the operator will be less and less."
Sermonet adds that fully automating an entry level edgebander for push-button changeover would require seven servo motors. "Market demand is driving prices for servo motors down," Sermonet says. "I think their use in edgebanders will be more common within a few years."
David Harris, edge processing specialist for Stiles Machinery Inc. of Grand Rapids, MI, says the use of servo motors and CNC for edgebanding can create sticker shock. "But more customers are job shops or are doing one kitchen at a time. If they are not taking advantage of CNC, they are missing out. They have got to look down the road beyond price and realize how much servo motors can save them for adjusting for edge thickness, height and more. It goes back to considering the long-term value of the machine. If you invest in the right amount of technology today, you'll save in the long run."
Hannigan adds, "The cost is easily justified with very fast payback through reduced labor costs, reduced waste and bad parts, less downtime and increased production."
Ed Moran, edgebander product manager for Biesse America of Charlotte, NC, says customers should weigh the benefits of automating setup using pneumatic or servo devices. "Automatic, quick-position work units make the machine capable of going from solid lumber with a flush cut to a 3mm PVC material with a radius finish to an HPL edge with a 15-degree bevel finish. For the operator, it is now as simple as only having to select from the actual program from the controller for the type of finish the product must have.
"It is our responsibility (as machine sellers) to properly explain to the customer the benefits of a pneumatic, multi-positioning work unit and that of a full servo-adjustable work unit. The servo-adjustable work unit in many cases is more expensive in the actual up-front investment of the machine and it is also more expensive to repair," Moran continues. "I have found that for 99 percent of the customers looking for automation of the work units, a simple two to four pneumatic-position work unit does just as good as do the servo units."
Pre-Milling for Precision
As Sermonet and Lillard noted earlier in this article, pre-milling is becoming a more popular feature on edgebanders of all sizes. Yet, Moran notes that he thinks pre-milling is still "under-appreciated" by many edgebander users.
"Pre-milling is a unit with two counter-rotating motors with quality cutterheads placed at the front end of the machine, prior to the glue unit, to cleanse the face of the panel or to remove a panel saw scoring line or fuzz that a nested-based machine with dull tools can create," Moran explains. "Pre-milling, if used correctly, only removes 0.1mm to 0.2mm, an amount of (the substrate's) material that will be compensated for by the actual glue spread.
"It does not matter if you have the best panel saw or the best nested-based machine to cut and prep your panel," Moran adds. "I truly believe that customers who apply all types of edges, such as HPL, 3mm PVC and solid lumber, and do constant changeovers, can only achieve the tightest, cleanest glue joint with pre-milling."
Sermonet says, "One of the reasons pre-milling has become popular on entry level edgebanders is because many small companies are utilizing table saws and pre-milling is the way to get a perfectly clean, square edge."
"We're definitely seeing a resurgence of pre-milling," Lillard says. "Companies want to reduce glue lines and to get a jointed edge with no scoring line or chipping. Pre-milling gives the best edge quality possible."
Avoiding Sticky Situations
Cleaning out a glue pot is a required maintenance routine and drudgery.
"The development of non-filled glues has clearly reduced glue clean up and downtime of machines," Moran says. Yet, he adds that "many customers have not heard of them" even though they have been available for several years.
"The old story of glue pots burning glue and not operating properly with adhesive is totally incorrect," Moran says. "Much of this has to do with the type of adhesives that are used. A non-filled glue, if used correctly, will not burn or change color and will reduce the maintenance factor of a glue reservoir on any edgebander in the market."
Moran notes that non-filled should not be confused with clear glues. He suggests that edgebander users consult their adhesive supplier for additional information.
"Most edgebander manufacturers have, or are introducing, GÃÆ?Ãâ?ÃÆ?ÃâÃÂ¿quick-change' glue systems," Moran adds. "This feature makes it very simple to get to, and remove, the glue applicator and/or the glue reservoir from the machine. This was a process that a few years back could take up to 30 minutes; with some manufacturers it now only takes three minutes."
"Glue pot design has improved immensely," Lillard says. "Today's glue pots are not something to be afraid of. They can heat up in eight or 10 minutes as opposed to a half hour or more for the last generation of technology, and the electronic controls help prevent overheating and burning of the glue."
PUR Glues Coming of Age
Hannigan points to polyurethane reactive hotmelts as a significant development. "These adhesives have special properties that make them resistant to high temperatures and virtually waterproof," Hannigan says. The fact that PURs cannot be reactivated after they crosslink, he adds, "presents problems for standard glue pots since the glue cannot be re-melted after it has cooled and hardened." As a result, he says, "Special technology has been developed to turn open glue pot systems into closed, sealed systems, which will allow better use of these systems."
Hannigan says edgebander manufacturers have developed less expensive systems that allow the use of standard EVA and PUR adhesives. "These simple, closed-glue systems allow quick changes from one adhesive to another...and enable the end user to have greater confidence in the stability of the glue joint when product is subjected to adverse conditions. This has allowed many end users to penetrate specialty markets that may have been difficult before, such as marine applications, laboratories and toilet partitions."
Lillard also notes the evolution of PUR technology. "We've worked very closely with customers using traditional glue pot technology with closed-flow-through systems, either using hot-melt pellets or a 2-kilogram cartridge system. We've also developed a table for removing PUR glues from the glue pot. This needs to be done at least once a week. You simply disconnect the glue pot and plug it into the table to bring it to melt temperature. You can extract up to 95 percent of the glue automatically and scrape the rest out."
On the adhesive front, Harris says, "We're hearing some discussion of clears and unfilled adhesives, and also PURs, but traditional EVA glues are still taking the lion's share of the edgebanding business." He adds, "We are seeing a little more PURs, especially for exterior and high-heat and humidity applications," but that most wood products companies are still put off by the greater expense and cleanup required for using PURs.
What Else Is New?
"What I see happening with edgebanders is more evolutionary than revolutionary," says Harris. In the case of edgebanding materials, for example, Harris says, "There's nothing stunningly new in the marketplace. On the horizon, though, we may see polypropylene replace PVC in some applications, especially among the office furniture manufacturers because they are becoming so GÃÆ?Ãâ?ÃÆ?ÃâÃÂ¿green' conscious."
Harris says applying polypropylene edgebands is "subtly different" than working with PVC. "It's typically softer than PVC, so you have to be a little more careful of smearing caused by heat generated from the cutting tools."
Harris also notes new technology for edgebanding lightweight honeycomb panels. "You can use your edgebander to insert a reinforcement strip on the panels that eliminates a frame. You just cut into the material slightly, insert the reinforcement strip and then edgeband over it. It's an easier process that requires less material."
"One of the hottest things coming is aluminum and aluminum-finished edgebanding," Lillard says. "It's very popular in Europe where people like the trendy look of aluminum. In the United States, we're seeing it become more popular in kitchens and store fixtures."
Lillard says "real aluminum" edgebanding is typically 1.5mm or 2mm thick. "The trick is not in applying it, but finishing it. We offer a unit for embossing patterns onto the aluminum to remove knife marks and restore the matte finish. You can [add] waves or other patterns to achieve different effects."
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