The hydraulic system of the hot press has two basic operational requirements: applying pressure to the workpiece and driving the hot press plate to end a specific movement. The rapid closing and the stability of holding pressure are important goals for judging the function of the hydraulic system.
Because the heating and curing of the glue during the veneer should end at the pressure holding stage, the fast-closing speed is beneficial to the process and power. On the one hand, it can reduce the heating of the slab under non-pressure and prevent excessive water loss on the slab surface Warpage is caused, which also prevents the pre-curing of the glue and reduces the quality of the veneer; on the other hand, it can shorten the adjuvant time and the productivity of the traveling press. In order to make the opening and closing of the press stable, it is generally equipped with mechanical synchronization equipment or may use the hydraulic system to maintain synchronization.
The hydraulic cylinder is the central part of the hydraulic system. Most wood processing presses now use plunger hydraulic cylinders. Large-diameter cylinder plungers are mostly made of alloy casting, which is characterized by high hardness, thick hardness layer, and scratch resistance. The utility is better than carbon steel heat-treatment plungers; small-diameter cylinder plungers are mainly made of carbon steel heat-treated hard chrome-plated, The surface hardness layer is thin.
Because the hot press generally requires fast opening and closing speed and accepts impact pressure, the cylinder needs to choose a higher strength material. For the general small-diameter, long-stroke hydraulic cylinders, seamless thick-walled steel pipes can be used for manufacturing. For some demanding cylinders, casting or casting cylinders can be used.
Generally, the working surface of the hot press used for wood processing and furniture manufacturing is relatively large. In order to make the pressure spread evenly, and considering the rationality of the structural installation, the multi-cylinder structure is mostly used.
There are not many problems in the production of the hot press itself, but a large part of them are in the hydraulic system, such as oil leakage and failure to maintain pressure. Many common knowledge and requirements about the hydraulic system can not be described here, but it should be paid great attention to in the selection.