Factors influencing the edge bending quality and efficiency of wood based panels furniture
The quality problems of edge banding of wood based panels furniture parts are mostly found in the glue joints and the edge banding strip itself. The operator, selected substrate, edge bonding material, adhesive, edge bonding machine, operating environment and other factors will affect the edge bonding quality and efficiency.
2.1 Operators
For traditional manual edge banding and semi-automatic edge banding, the edge banding quality has a great relationship with the operating level of operators. Skilled operation and correct control of process parameters can reduce the phenomenon of edge banding strip degumming.
2.2 Base material
The flatness, density, moisture content and internal stress of the substrate itself will directly affect the trimming and edge bonding effect. If the base material is placed for about a day after cutting, the quality is the best. The thickness of the substrate will also affect the pressure effect of the edge banding strip. At present, high-end edge banding equipment has expanded the thickness difference of the substrate, effectively reducing its impact on the quality. After processing and testing, when the width of the base material plate is less than 100 mm, the quality of edge banding decreases significantly, and edge collapse and chamfering occur frequently.
2.3 Edge bending materials
The surface roughness of the gluing surface of the edge banding strip affects the edge banding quality. If the surface of PVC/ABC/melamine plastic edge banding strip is too smooth, it is not suitable for edge banding; If the surface is too rough, the edge bonding strength will be weakened. If the edge banding strip is stored for a long time, its surface will produce an aging layer, which will affect the bonding performance; When bending veneer/solid wood strip and other materials, pay attention to the thickness tolerance of wood materials; Melamine edge banding with too thin thickness has low bonding strength, high hardness, uneven incision and high rework rate.
In contrast, the thermoplastic edge banding material can not only realize the edge banding of small curvature radius forming surface, but also be applied to NC machining center processing; The adhesive speed of thin thermoplastic edge bending material is faster than that of melamine formaldehyde resin, and it is water resistant and heat resistant; The three-dimensional edge bonding material can directly paste the printed pattern on the board, and the pattern is still applicable when machining the curved surface, and it is easy to polish, so as to ensure the quality of furniture.
2.4 Adhesive (when hot melt adhesive is used for edge bending)
The performance and quality of hot melt adhesive affect the edge bending effect. Its melt viscosity, softening point, thermal stability and drying time determine the quality difference of the prepared hot melt adhesive. EVA hot melt adhesive has low viscosity and good versatility, and can be used to bond almost all base materials and edge bonding materials. Good heat resistance, tight joints and high final strength of glue joints; The polyolefin hot melt adhesive has good heat resistance and can reduce the looseness of the edge banding strip during heating.
PUR glue is a kind of active glue, which has both physical and chemical solidification. Good water resistance, solvent resistance, steam resistance and cold resistance. However, due to its reaction with moisture in the air, attention should be paid to storage. When used in the north, low temperature hot melt adhesive is generally used in summer and high temperature hot melt adhesive is used in winter. Too little glue can not reach the adhesive strength, and too much glue will lead to the floating tendency of the edge bending material.
2.5 Edge banding equipment
For the cutting tool, if it is not sharp, the bonding strength between the edge banding strip and the plate will be weakened, and the quality of end trimming and trimming will be affected; If the tool axis coaxiality is not high or the applied pressure is insufficient, the unevenness will occur. The early edge banding machine was not equipped with a milling cutter unit, so it was easy to have defects such as edge collapse and tearing when processing thick edge banding strips. Now, after the front end of the edge banding machine passes through the additional joint milling tool set, the milling cutter is partially engaged and the axis is angled to avoid plate end cracking.
The flat broach device is added at the end of the edge banding machine to remove the rubber thread or excess glue generated after edge banding, reducing manual work, thus improving the edge banding quality and productivity; For the gluing device, the roller type gluing device needs to heat the power and time and melt all the glue. The pre melt glue tank can shorten the heating time, and it needs to be cleaned or replaced when replacing the glue; The barrel type gluing device only needs to melt the amount of glue used, saving 70% of heating time, and the glue is not easy to cool and pollute; The gluing device of super particle extrusion has the advantages of the former, and the bonding quality is good.
2.6 Operating environment
Proper temperature and humidity are required when selecting hot melt adhesive edge bending process. The ambient temperature in the plant shall not be lower than 17 ℃. The edge can be preheated due to the falling off caused by different thermal expansion and contraction coefficients of the edge banding materials and the plate materials; The melt glue temperature of the gluing device should be kept to a certain processing temperature, and the temperature of the edge bonding machine temperature display should be higher than this temperature to avoid excessive cooling; The humidity of solid edge wood is generally controlled at 8%, and the surface is free of liquid, dust, etc. If there is resin in it, a primer like DorusND183/1 shall be added to enhance the adhesive force.
The stability and speed of plate feeding affect the quality and efficiency of edge banding. The smooth operation of the conveying track will reduce the wavy lines and uneven gluing during trimming; If the feeding speed is too slow, the glue will be cooled too early, and if it is too fast, the edge bonding material will be loosened. The feeding speed of the manual curve edge banding machine is about 4~9 m/min, the feeding speed of the general automatic edge banding machine is about 18~24 m/min, and the high-end automatic edge banding machine can reach 36 m/min. In northern winter, the feeding speed of the edge banding machine should be 18~21 m/min. The temperature of the gluing device can also be properly adjusted to increase the efficiency with higher feeding speed.
3. Development trend of intelligent manufacturing edge banding
