In the realm of high production cabinet making, edge banding has advanced as much as any technology from innovations in machine automation and computerisation, and developments in modern materials. Read on for, ‘almost everything you always wanted to know about edge banding but were afraid to ask.’
The basic equipment needs for most kitchen and bathroom manufacturers are a CNC nesting machine and an edge bander. Some high-volume enterprises use an automated ‘beam’ saw to cut multiple sheets at a time because in any cabinet, nearly half of the carcase parts are the same size (the sides). Cutting these in a stack on a beam saw can be a more efficient way of generating parts for the drilling machine. No matter how the parts are cut and drilled, the non-negotiable machine in the process is the edge bander.
Edge banding covers the exposed edges of materials, giving the appearance of a solid or more valuable material. Some cabinet doors are now either sprayed or vacuum-formed but a lot are still edge-banded. All carcase parts with an edge seen by the customer must be edged. It is advisable to apply an edge tape to all exposed edges to avoid water penetration resulting in swelling of the board. Your other machines are important in producing a satisfactory product, but the edge bander is the machine that can bring a company undone if the finish is not of high quality.
The right feed speed and the correct, quality tools (cutters) will produce a chip-free panel but it’s the edge bander that will finish off the cabinets to the standard expected by most consumers. A tight-fitting edge tape showing the smallest possible glue line is most desirable. The term ‘zero glue line’ has been thrown around for many years now, first with prohibitively expensive plasma, or CO2 and Diode Laser edge banding machines. Then, about ten years ago now, hot-air technologies brought down the cost of ‘laser’ edges and six years ago, near-infra-red (NIR) was first displayed at AWISA in Brisbane.
When one element is joined to another there will be a line of some kind, however insignificant and microscopic that may be. The goal is the make that line as small as possible and modern equipment is capable of amazing results approaching the ‘zero’ visible line. Plasma and laser do this best if you can afford it, but very few Australian manufacturers use this technology. Hot air and near-infra-red are more affordable technologies that do almost as good a job, at least as far as human sight is able to determine. PUR is also able to do a remarkably good job producing a near-invisible join and even companies producing cabinetry for laboratories use this.
Production trends for cabinet manufacturers have been moving toward smaller batch runs for a number of years now. The marketing term ‘batch size one’ has been used by the Homag Group for a decade or more. Cutting and drilling all the cabinets for a kitchen on a nesting machine is a form of batch size one but the real meaning is to produce one part. This requires more set-ups and in the case of an edge bander, may require a change of edge tape and adjustment to the units on the machine. It could take five to fifteen minutes just to change from one edge thickness or edge detail to another. To achieve quick changeovers, computer controls play an increasing role in woodworking equipment and even lower-cost machines are now available with this.
Machines and Tools
There are many types of edge banding machines available, starting from a small, hand-fed machine using pre-glued edge tapes. The quality of edges produced on such a machine can be described as poor to average. For the production manufacturer however, a power-feed machine with either a glue pot or glue cartridge system will produce a consistently good product. Some machines can also use other adhesion technologies, and these require some changeover of the machine, however the time to do this is being reduced as machinery is developed further.
The other adhesion technologies edge banders use applies an edge material using specialised tapes with a co-extruded ’functional’ layer melted by either plasma; laser; hot air; NIR and soon, microwave, and pressed onto the panel. Plasma is a special mixture of air and gas that activates the functional layer on the reverse of the co-extruded tape with a temperature of over 1000°C. It is expensive and rarely if ever used today, especially in Australia. Laser melts the functional layer with a laser beam operating in a wavelength range of approximately 980 nanometres. Laser is also expensive but used by large, high-volume manufacturers running at high feed speeds.
Co-extruded edge tapes can also be ‘melted’ by forcing hot air onto the tape, a process developed by the Schugoma Company of Germany they call ‘fusion technology.’ The West Australian company Beyond Tools showed the first edge banding machine to use hot air to ‘activate’ the functional layer. It only took two years for Biesse (Airforce), Homag (Airtec) and (now) Altendorf’s Hebrock (Airtronic) to present either their own system, or the Schugoma technology on their machines. Felder and SCM (AirFusion) followed shortly after. The technology is affordable, but it can be noisy and uses a lot of compressed air and actually, not everyone is sold on it.
Near-infra-red ‘radiation’ (NIR) is one of the newest technologies developed to activate the functional layer on fusion edge tapes. At the same time, the Weinig Group (Holz Her) created a quick changeover unit ‘Ltronic’ so you could use either the NIR or Glu-Jet unit. NIR heats and penetrates the edge material from the outside to the inside. NIR has no heat up time, no noise and does not require huge amounts of compressed air. IMA (Wood Tech Group) developed IMALUX three or so years ago. IMA won’t release details of how it works but our guess it’s similar to NIR. And at Ligna last year Felder Group brought out ‘GlueBox’ a system that applies PUR adhesive extruded as a tape that is applied inside their new application device.
Most cabinet carcases produced in Australia are white so your edge bander will predominantly be used to apply a white edge. There may be other seen parts on a more ‘designer’ kitchen where the parts, numbering less than ten pieces are a different colour. For these and coloured carcase parts, the edge bander settings must be changed. Manual set-up machines can be time consuming to change from one edge thickness or detail to another.
Manual machines are cheaper and may still involve the use of limit-switches that would get caught up with edge banding materials or glue and would often jam or break.
Recently, machines rely on PLC (programmable logic control) to control the functions as the panel progresses along the machine. Edge banders now operate at higher speeds, but the biggest advantage is decreasing set-up times. Automated edge banders are more cost effective than in the past but will still add ten to thirty percent to the cost of the machine. There are a number of very good automatic PC-controlled machines available at a very reasonable cost including Toughcut (Beyond Tools); Bimatic and OTT (Tuckwell Queensland); OTT (I&J West Australia); NikMann (Forza Group); PE (Major Woodworking); Cehisa (MGM Machinery); and KTD (Leda Machinery).
A number of CNC machines have also been capable of applying edge bandings for some years now. Homag CENTATEQ; Biesse Rover A Edge; SCM Morbidelli p200 are three current machines that will do this with PUR adhesive and even Fusion edges, on straight or curved components. From New Zealand, but with machines installed in Australia, Duncan Such’s ‘Revolution180’ by Vector is a machine that automatically applies edges to pre-cut panels of any shape. It’s a dedicated edge bander so it won’t slow down production like a full-function machine does while it bands the edge.
One thing that’s often overlooked when using high-end equipment are the cutting tools. The edge bander is capable of producing the highest quality product but only if the company is using quality tools. Cabinet manufacturers work with a mix of quite different edge materials and thicknesses and batch sizes are becoming smaller. Economical changeovers are made easier with the use of smart tooling such as the Leitz profile cutter ‘flexTrim3’ that allows automatic changes between three profiles within a few seconds without a tool change. The tool has diamond cutting edges for long life and is available at short notice.
Another issue when edge banding is the noise that can be generated, mostly at the hogging (pre-milling) cutters. Leuco released a new ‘AirStream’ hogging tool at the last Ligna two years ago that cleverly directs air through the tool body, eliminating air pressure areas that create noise. Suitable now for the Holz Her brand, the tools achieve a 97% improvement in chip removal, so the chips aren’t being machined several times as they whirl around the tool before being collected by the specially designed dust hood. Airstream tools are also available for edge rounding tools.
Edge Banding Materials
The materials used for edge banding are edge tapes, manufactured or supplied by most of the panel suppliers; and adhesives. Most of the adhesive products are supplied out of Europe. The major adhesive players include Rehau; Surteco (who supply Döllken); Kleiberit and Henkel.
ABS (acrylonitrile butadiene styrene) is a durable and impact resistant, mechanically, and thermally resilient, environmentally responsible thermoplastic material. ABS is a ‘green’ material and can be recycled. If it’s burned, the resulting gas is not harmful. ABS edging responds well to heat, and at higher temperatures, it’s malleable and when cooled, becomes rigid. This chlorine-free plastic has been successfully used in the furniture industry for over 30 years.
Polyvinyl Chloride, or PVC, is the most commonly produced and least expensive plastic on earth. Technically a synthetic plastic polymer, its composition is flexible enough to be rolled into spools. Although PVC can be recycled, the gas from burning is environmentally harmful. Decomposition also takes longer making PVC among the least green edging materials.
PP (Polypropylene) is mainly used in pipe extrusion and the packaging industry. For more than 20 years, the chlorine-free semi-crystalline plastic has also been increasingly used in the furniture industry because it is particularly impact-resistant and durable. It is also chlorine-free and can therefore be disposed of easily and without separation from the panel. PP guarantees a long service life for milling and other cutting tools, which greatly simplifies further processing. PP edge bands can be used in offices, kitchens and bathrooms, shop fittings as well as contract furnishing. PP is used for fusion edge banding.
3D PMMA (Polymethyl methacrylate) is a well-established, high quality synthetic thermoplastic that sets new technical and aesthetic standards for furniture edge bands. The transparency of the acrylic is better than that of glass making it ideal for the production of 3D edgings. The positioning of the decorative finish on the rear of the edge band means that it is fully protected against abrasion and damage, even when subjected to high levels of wear and tear.
Melamine is a special paper that’s saturated and covered with lacquer. The lacquer adds resistance and strength to the paper. Melamine is not durable and is best used where there’s not a lot of traffic. Despite the addition of lacquer, melamine is still paper and so it is technically less waterproof than other edges.
Fusion Edge Banding refers to a technology where the ‘functional layer’ of ‘co-extruded’ edge tape is melted by Plasma, Laser, hot air or NIR technologies, and applied to the panel in an edge banding machine fitted with one of these technologies. Because there’s no glue involved, there’s no glue line and visually, there’s no difference between the hot air/laser process to laser edge banding. Until a few years ago all fusion edge tapes were imported, and the technology did not take off, but the edges are freely available, and some is even made here in Australia.
The claimed advantages of fusion edge are a permanent invisible seam thanks to a pure polymer, adhesive-free solution; an exact colour match of the functional and decorative layer; freedom of colour and decorative design choice as all product ranges can be used for laser processing; increased resistance of the boards to heat and moisture; increased process reliability; minimised maintenance work and reduced set-up times and the matching of the edge band material/primer/adhesive is no longer necessary. Despite these claims, many manufacturers argue PUR does an overall better job at a much lower cost.
Wood veneers and solid timber strips can also be applied to panels for use in veneered furniture construction. The use of iron-on edges is now almost entirely the realm of the hobby woodworker. T-Moulding as an edge finish is now almost entirely non-existent.
EVA (ethylene-vinyl acetate) is still possibly the most common hot-melt adhesive used in edge banding. It is applied at between 180 to 220 degrees Celsius and can be melted many times without losing its stickiness, so there isn’t a lot of waste. It cures quickly and is relatively inexpensive. EVA hot melt adhesives are classed as filled and unfilled. Filled adhesives cost less and offer good performance and a high final bond strength. The addition of fillers offers advantages such as preventing stringing and are beneficial when running porous chipboard. Unfilled hot melt adhesives can be applied at lower coat-weights to minimise the glue line and achieve tighter joints. Use EVA to bond PVC, melamine, ABS, acrylic and wood veneer.
The first reactive PUR (polyurethane resin) hot melt adhesives were launched in 1987. PUR sets quickly and strengthens its bond over several days to achieve much higher bond strength as it is more of a chemical reaction than mechanical. PUR glue is applied at a lower temperature (130 to 150C) than traditional hot melt EVA glue and the re-melt temperature is much higher, so it resists de-lamination in hot situations such as oven surrounds. The process uses 40% less glue than hot-melt so it saves production costs, and you get a much thinner, near invisible glue-line. The minor drawback to using PUR is that the glue starts to ‘go-off’ once it’s exposed to air and must be kept in sealed containers.
PA (polyamide) hot-melt adhesives are designed for high performance in severe environments. They are made with organic bases such as seed oils and are noted for high heat tolerance. They deliver an exceptional bond but can be a little more susceptible to moisture than other options.
APAO (amorphous polyalphaolefin) hot-melt glue is popular in the automotive world: it resists fuel and acid better than most adhesives. It also has a longer open time and slower set time than EVA glue. It has a high melting point and thus higher heat resistance, plus a longer open time than EVA. The future could lie with adhesives developed for high-tech applications, such as silicone-based versions that retain more flexibility.