Edge Banding with Optical Zero Joint

Woodworking requires the highest quality and efficient processes for flat lamination, profile coating, and edge banding. The variety of panel and edge materials and the use of different adhesives call for flexible and efficient solutions. In addition, the digitization trend affects the degree of automation of the plant and thus the technology and software to be used.

To achieve the quality standard of an “optical zero joint,” PUR hot melt adhesives are often used for the edge banding of kitchens, bathroom and laboratory furniture. Compared to EVA hot melt adhesives, PUR hot melt adhesives are resistant to temperature, water, and chemicals. This ensures a high and long-lasting adhesion even with small application quantities. Thus, adhesive application can be reduced to a minimum, thus, reducing costs.

Traditionally, roller application systems are used for edge banding. A so-called open system consists of a pre-melter that melts adhesive and fills it in a basin, and a roller that applies the adhesive to the substrate. Rather closed systems with melter and wide slot-type nozzle head are currently used as an alternative. In terms of application quality, cost optimization and efficiency, closed systems are unbeatable.

Whether EVA, polyolefin or PUR adhesives are processed, whether a basin is filled using a pre-melter or a complete nozzle system is required, Robatech offers the right solution. The Robatech melters can be connected to the host machine via a variety of interfaces and integrated into existing systems.

In edge banding with a slot-type nozzle, hot melt adhesive is applied to the exposed sides of materials such as MDF, plywood, and coated chipboard or blockboard and chipboards, as well as kitchen countertops. The desired adhesive application width can be set automatically or manually. Depending on the panel material, edge strips made of PVC, ABS, acrylic, melamine, wood or wood veneer are pressed onto the glued edge after adhesive application. A layer of edge sealant can be applied first for porous panels. The result is a smooth surface, which allows to achieve an optical zero joint in the subsequent edge banding.

Using the closed nozzle system, the adhesive amount can be fed precisely and applied with excellent repeat accuracy. This reduces adhesive consumption to a minimum and achieves significant savings over a roller system. In addition, the efficiency is increased by short cleaning times, fast adhesive/color changes and ease of operation. Furthermore, the pivotable mounting bracket of the coating head allows an easy adjustment of the contact force and a flexible positioning of the coating nozzle relative to the workpiece. Double-sided machines benefit from consistent spare parts since the same coating head is used for left-hand as well as right-hand guidance. Optimal positioning together with adhesive quantity control and the adhesi­ve retraction system achieve repeatable gluing with clean cut-off.