1. Double roll glue coating machine.
The double-roll glue coating machine is mainly composed of upper and lower cots and grooves. The lower cots are immersed in the grooves, and the glue of upper cots is transferred by lower cots. When the veneer passes through the middle of the two rubber-coated rollers, it contacts the rubber-coated rollers so that the glue on the rollers is coated on the upper and lower surfaces of the veneer. The amount of glue coating depends mainly on adjusting the gap between upper and lower cots and the pressure of upper cots. The thicker and narrower the veneer, the greater the pressure of the roller on the veneer, the smaller the amount of glue applied; on the contrary, the larger the amount of glue applied. The shape and quantity of grooves on the roller also affect the sizing amount. It is advisable that the liquid level height of the glue in the glue tank should reach 1/3 of the diameter of the lower glue roller, and too large or too small will affect the glue amount.
2.Three-roll glue coating machine.
The three-roll glue coating machine is to add an extrusion roll beside the top or bottom roller. The amount of glue coating is determined by the gap between the top roll and the extrusion roll. The extrusion roll is arranged next to the top coated roll, which is supplied by the rubber pump through the rubber tube. The groove formed between the top coated roll and the extrusion roll is used to store the rubber. The extrusion roll is arranged next to the bottom coated roll to supply the rubber from the rubber groove, and the glue amount is not affected by the liquid level of the rubber groove. Although the three-roll glue-coating machine has good glue-coating quality, it can only control the single-side glue-coating quantity, so it is not widely used.
3. Four-roll glue coating machine.
Four-roll glue-coating machine is to add an extruding roll beside the upper and lower glue-coating rolls to control the glue-coating amount on the upper and lower surfaces of veneers respectively. The linear speed of extrusion roll is 15%-20% lower than that of coating roll, which plays the role of scraping rubber, and the gap between extrusion roll and coating roll is adjustable to ensure that the thickness of upper and lower rubber layers is uniform. The upper and lower cots are supplied with glue at the same time, and they do not interfere with each other. It is not easy to jump when gluing. It is a widely used gluing equipment.
There are two ways to arrange the extrusion rollers of the four-roll glue coating machine.
1) The upper and lower extrusion rollers are arranged on both sides of the coated rollers, and the rubber pumps supply rubber through the hoses respectively.
2) The upper and lower extrusion cots are all located on the feeding side of the coated cots. The upper coated cots are supplied by the rubber pump, and the lower coated cots are supplied by the lower rubber groove. Because the arrangement of rollers and the way of rubber supply are different, their functions are also different. The former is uniform and can save rubber materials, while the latter is suitable for the situation of high productivity.