Sheet extrusion machine technical requirements: 1.
Under the vent plastic pressure is zero.
To avoid the melt flow vent.
Ensure exhaust in the period of spiral groove is not completely filled with plastic, can achieve zero voltage requirements.
System cup machine exhaust for this section of the spiral groove of the many.
Under the vent plastic melt completely.
Only in this way, between outlet and inlet have good sealing, vent place to have higher gas diffusion system.
Sheet extrusion machine working principle: plastic on the vent screw after three process;
In the first order after compression, heating achieve basic plastic state;
Basic plasticizing the plastic into the exhaust section, horizontal sheet machine, the exhaust section of screw groove, suddenly and a vacuum pump suction, pressure sharply lowered to negative pressure state.
Plastic melt by the compressed gas and gasification of volatiles in the melt foaming, plastic thermoforming machine under exhaust section of screw mixing bubble burst, escape from vent gas is vacuum pump;
After exhaust treatment of molten material through the second compression section and the second measurement section, lunch box machine are compressed and again into a homogenization, from the nose out of the required products.
Sheet extrusion machine note: 1.
In the powder mixed with air between aggregate particles.
As long as the screw rotation speed is not too high, generally speaking, this part under the pressure of gas can be increased gradually from the eduction in hopper.
BOPS thermoforming machine but when rotation speed is too high, material fast forward movement speed, all gas may be too late, so as to form bubbles in products.
Gas is the material absorption of moisture from the air, they have become water vapor when heated.
For those of moisture absorption is plastics such as PVC, PE, PS, PP, and so on, generally do not what problem, sheet material machine the small amount of water vapor can also be from the eduction in hopper at the same time.
But for some, PSF engineering plastics such as PA, PET, ABS, PC, etc. , because of their moisture content is too big, lid machine water vapor is too much, so too late from the eduction in hopper, which was formed in the course of products of bubbles.