Views: 9 Author: Site Editor Publish Time: 2020-07-07 Origin: Site
The cold press is a machine used in the plywood industry. It can not only cold press the plywood, but also suitable for the production of artificial boards such as particleboard and fiberboard.
The purpose of the cold pressing of particle board is to make the structure of the board more compact, to eliminate the residual air in the slab, to prevent the air from rushing out and damaging the slab during hot pressing, and to reduce the thickness of the slab. This can simplify the structure of the cold press and also Increase output and ensure the quality of particleboard.
The cold pressing process requirements for particle board are: the general slab compression is 1/3 to 1/2; the cold pressing pressure is 1.5 to 1.6 MPa, and the minimum is not less than 1.0 MPa; the cold pressing time is 10 to 30 s. After cold pressing, the slab usually rebounds, and the rebound rate of the slab is preferably 15% to 25%. There are two cold pressing methods for particle board slabs, one is periodic flat cold pressing, and the other is continuous cold pressing.
Periodic flat cold pressing is divided into upper cold pressing and lower cold pressing, and upper pressing is more recommended here. In this way, cold pressing requires several conveyor belts, which are used for slab weighing, flushing and cold pressing machine plate mounting device and maintaining a distance during flushing operation, so as to ensure the continuous slab when hot pressing the plate run.
Continuous cold pressing is in a continuous cold pressing machine, the slab is moved in a compressed state, and the slab is directly paved and cold pressed on the paving steel belt. Therefore, it is required that the speed of the steel belt is fixed after being determined according to the needs of paving and cold pressing. There are many types of continuous cold pressing, which can be roughly divided into two types, one is a roller cold press, and the other is a crawler cold press.
The roller cold press is composed of 5 pairs of small pressing rollers and 2 pairs of large pressing rollers. The upper pressing belt forms a closed loop and moves along the first pair of large pressing rollers and the upper and tensioning rollers of 5 pairs of small pressing rollers. All the pressure rollers in the upper pressure belt are hung on the beam. There are adjusting devices at the two ends of the beam to allow the beam to move up and down. The front end of the beam is adjusted by the adjusting wheel through the screw rod. The rear end of the beam is connected to the hydraulic piston rod to control the up pressure. The pressure of the slab with the inner pressure roller.
The lower pressing belt moves along the lower rollers of 2 pairs of large pressing rollers and 5 pairs of small pressing rollers. The inner pressing rollers of the lower pressing belt are installed on the frame or the machine base. Two pairs of large pressure rollers are equipped with a power transmission gear at one end, which is the driving wheel that drives the upper and lower pressure belts.
The formed slab is sent to the pressure zone of the cold press by the slab conveyor belt, and the slab belt is run between the upper and lower pressing belts. As the distance between several pairs of pressure rollers gradually decreases from front to back, the pressure on the slab gradually increases and the amount of slab compression increases. When passing the last pressure roller, the distance between the pressure rollers is the smallest and the pressure is the largest, so that the slab meets the compression requirements. The speed of the slab conveyor belt passing through the cold press is 1 to 6 m/min, and the linear pressure of the pressing roller is 200 to 600 N/cm.
Crawler cold press (also called high-pressure pre-press) has a circulating plastic surface conveyor belt. Through the space between the paver and the cold press, the cold pressed slab is cut by a cross-cut saw. The platen of the cold press is above or below the press, and the platen rotates in sections around the end rollers. The speed of this cold press can be adjusted with the paving speed.
The above content is about the cold pressing of particle board, I hope it will help you. For questions about plywood machines, you can contact us at any time. Our company can provide customers with a complete set of plywood production solutions according to customer needs.