SU579877A3 - Device for moulding thermoplastic castings with hard skin and cellular core - Google Patents

Description

A device for forming thermoplastic branches with hard shell and four-core core works in the following way.

A thermoplastic pre-mixed with a certain amount of a blowing agent is plasticized in the extruder 1. The first cast is molded by injecting a polymer melt into a mold 2, placed under the pressure of the compressed gas in the reservoir 1O, through the distributor 3, is installed. in the position of the joint of the extruder 1 with the form 2. After the formation of a hard shell of the required thickness, the pressure of the compressed gas in the frmi 2 is released into the distributor 3 and is switched to the connecting position pho) we 2 with 1 spike 4 ohm for 1 cones of the material.

The excess material resulting from the foaming of the molten form 2 enters the space formed as a result of the piston 5 being moved by the actuator 6 through the cylinder 4. Then the distributor 3 switches to the position in which extruder 1 is connected: with cylinder 4; Because of this, the sprue channel is ash1 and the cured casting is removed from mold 2, the melt injected by the extruder 1 penetrates into rod 4 and presses on the total surplus material from the previous casting, stirring the piston 5 to the top of shlindra 4. To prevent further foaming of excess material. 6 somewhat increases the vavlenve, on the piston 5.

After a sufficient amount of melt has been accumulated. For a complete mold of form .2, distribute 3 is inoperative to the position of the joint. non-foamed magvil sludge, and in the shaping mold - foamed zlvshek - material from the previous casting, which fills the inside of the moldable molding. After the shell is straightened off, the pressure on the pores of the shenol 5 is released and the core starts to foaming, when the atom of the excess material from foaming again ages from form 2 to cylinder 4,

Then the cycle is repeated.

The design of the device allows the implementation of another pitch pattern for filling the form 2: the non-foamed material is applied directly to form 2 extrude ptepoM 1 before filling it with 5 O-9 O% volume

and then the piston 5 refills the mold with a foamed excess of the material from the previous casting.

To form castings of simple geometries, the cavity of the mold 2 is filled up with 10-5% of its volume with compressed gas directly 3 shafts 4 connected by a pipe 8 with a source of compressed gas 1O. After the outer shell is formed and to create the condition of melt foaming in the shaft of the rollback, the gas is returned back to the cyclical well 4

In order to eliminate blistering blistering in case of premature foaming during plasticization of the polymer in the extruder and to ensure the use of the foaming agent of any three extruder is sealed, it can be connected by pipeline 9 to the reservoir of compressed gas 10 and the atmosphere.

The proposed device allows to obtain therm-elastic castings with good quality and the outer shell and cellular core.

Claims (3)

1. A device for forming thermoplastic castings with a hard shell and cellular core containing an extruder and a hermetic form connected to a cut of a compressed gas, characterized in that, in order to improve the quality of the optics, the device is equipped with a spaced rotor distributor located between the form and the extruder a cylinder connected to it for excess material with a driving piston diluted in it. 2. The device according to claim 1, in connection with the fact that qilin f for excess is connected to the pipeline with a peaefw pair of compressed gas in the atmosphere. 3. Device .in paragraphs. 1 and 2, that is, that the acre {Yerdinen pipelines with a tank of compressed gas in the atmosphere. Sources of information taken into account at the expert: 1. Zavgorodniy V, K. Mechanization of n: automatic processing of plastics, M., ivd. Mashinostroenve, 197O, p. 22O-221, FIG. 118. 2. Journal, Modern Pfcistic, 1969, 46, NO a, p. 68-70. one