JPH0528167B2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field to which the Invention Pertains> The present invention is directed to the prevention of water content and monomers in materials used in injection molding machines.
The present invention relates to a degassing device for an injection molding machine that effectively removes other impurities (hereinafter simply referred to as vaporized substances).

<Prior art and its drawbacks> Normally, materials containing a large amount of vaporized substances are molded using a vent-type injection molding machine, but this type of molding machine has a vent hole in the barrel, and the inside of the barrel When the pressure is increased, the molten material enters the vent hole, which has the disadvantage of eliminating the venting effect. Therefore, it has been difficult to change materials, colors, etc. by applying relatively high pressure inside the barrel.

In addition, in order to compensate for the above drawbacks, we do not provide a vent hole in the barrel, but by providing a sub-flight in the screw inside the barrel, we create high pressure inside the barrel, causing vaporized substances to flow back to the material supply side, and material This method of degassing from a feed hopper or the like solves the problem of vent holes mentioned above, but it also has the disadvantage that the deaeration is not sufficient to make the material unnecessary to pre-dry.

<Object of the Invention> The present invention eliminates the drawbacks of the prior art as described above, and provides injection molding that can be used at high pressures, can be used for material changes, color changes, etc., and does not require pre-drying. The purpose is to provide a degassing device for the machine.

<Summary of the Invention> In order to achieve the above-mentioned object, the present invention provides a vent portion in the feeder or hopper that supplies material into the barrel to remove vaporized substances flowing back from inside the barrel, and also removes the screw in the barrel. Injection molding characterized in that main flights are provided in the supply section, compression section, and measurement section from the material supply side toward the tip, and a sub-flight is provided in at least one of the three sections. It was used as a degassing device for the machine.

<Embodiment> Next, an embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 1 is an injection molding machine, and a screw 3 is inserted into a heating cylinder (barrel) 2 so as to be movable forward and backward by a drive device (not shown). The screw 3 is composed of a supply section F, a compression section C, and a measuring section M in order from the material supply side to the tip. In addition to the main flight 4, a sub-flight 5 is provided in the compression section C, and the inside of the heating cylinder 2 is provided with a sub-flight 5. pressure is increasing. Therefore,
The material fed into the heating cylinder 2 from the feeder device 6 is heated and melted by a heating device (not shown), while being measured by the screw 3 in a fixed amount and accumulated at the tip of the screw 3.
Vaporized substances and the like flow back toward the feeder side by the sub-flight 5 due to weir action, and are sucked by a vacuum pump 9 or the like through a vent hole 8 provided in a supply cylinder 7 that communicates the feeder device 6 and the heating cylinder 2.

<Effects> The above structure eliminates the disadvantage that the heating cylinder does not have a vent hole and the vent hole is clogged with molten material even if the cylinder is subjected to high pressure. The provided sub-flight allows vaporized substances to be discharged from the supply tube that does not come into contact with the molten material, so that the vaporized substances that flow back do not contaminate the material in the feeder device, and sufficient deaeration can be performed.

In the above embodiment, the subflight was provided in the compression section of the screw, but it can be provided in the metering section or the supply section depending on the properties of various materials and molding conditions.

Further, the material supply device is not limited to the above-mentioned feeder device, but may also be a compactor device that forcibly feeds the material into a heating cylinder, or a hopper that feeds the material by natural falling.In the case of a hopper, as shown in Fig. 2, A dividing plate 11 is provided to prevent vaporized substances flowing back from the cylinder side from contaminating the material in the hopper 10, and it is more effective to collect vaporized substances at the bottom of the dividing plate 11 and then suck them out. It is true.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention. FIG. 2 is a diagram showing another embodiment of the present invention. 2... Heating cylinder, 3... Screw, 4...
Main flight, 5...Sub flight, 6...Feeder device, 8...Vent hole, 9...Vacuum pump, F
... Supply section, C ... Compression section, M ... Measuring section, 10
...Hotupa, 11...Splitting plate.

Claims (1)

[Claims] 1. A vent part is provided in the feeder or hopper that supplies material into the barrel to remove vaporized substances flowing back from inside the barrel, and the stariyu in the barrel is connected from the material supply side to the tip of the supply part, compression part,
1. A degassing device for an injection molding machine, characterized in that a measuring section is provided with a full-flight main flight, and at least one of the three sections is provided with a sub-flight.