JPH0553919U - Nozzle for injection molding machine - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] Easy to replace and fix injection mold from injection device 1
Less heat transfer to. In a molten material injection molding machine nozzle 6 of an injection molding machine, a nozzle mounting member 12 detachable from the nozzle 6 is provided.
The heat-defective conductor is interposed between the nozzle 6 and the nozzle mounting member 12.

Description

[Detailed description of the device]

[0001]

[Industrial application]

 The present invention relates to a nozzle for an injection molding machine that injects molten resin into a mold.

[0002]

[Prior Art]

 FIG. 2 is a front view of a conventional injection device similar to the present invention. Reference numeral 21 is a raw material resin supply hopper attached to a heating cylinder (barrel) 22. Reference numeral 23 is a heater mounted on the outer surface of the heating cylinder 22, and the temperature can be adjusted by a temperature adjusting device (not shown). Reference numeral 24 denotes a screw that is inserted into the heating cylinder 22 so as to be able to rotate and move forward and backward. Reference numeral 29 is a potentiometer that detects the position of the screw 24 as an electric signal as the screw 24 moves back and forth. Further, 1 is a fixed mold, 2 is a movable mold, 3 is a cavity, and 4 is a sprue part. The temperatures of the fixed mold 1 and the moving mold 2 are kept at a temperature of about 50 to 100 ° C, although they change depending on the necessity.

A nozzle 6 is attached to the heating cylinder head 5 at the tip of the heating cylinder 22, and a nozzle tip 7 is attached to the tip of the nozzle 6. At the abutting portion of the tip of the nozzle tip 7 with the fixed mold 1, ceramic having a defective conductor is sprayed to an appropriate thickness, for example, 0.2 to 1 mm, or a thickness of 2 mm. Synthetic resins such as polyimide resin, fluororesin, acetal resin, and epoxy resin with a thickness of ~ 3 mm are used. In general, the nozzle temperature is maintained at about 200 to 350 ° C. like the heating cylinder 22. Here, R represents a resin.

The operation of the injection device configured as above will be described. First, the resin R supplied from the raw material resin supply hopper 21 is melted in the heating cylinder 22 by receiving the thermal energy transmitted from the heater 23. The resin R is supplied from the hopper 21 into the groove of the screw 24 and then is sent toward the screw head by the rotation of the screw 24, so that the resin is sent out from the screw groove portion to the void portion in front of the screw head.

In this way, the screw R is retracted during the metering operation, whereby the resin R is accumulated in the void formed in the front part of the head part. Then, after measuring the resin R, the injection device 100 is moved forward to bring the nozzle tip 7 into contact with the fixed mold 1, and then pressure oil is supplied to the hydraulic cylinder 25 to move the screw 24 forward. The resin R filled in the front voids is filled in the cavities 3 through the sprue portions 4 provided in the fixed mold 1.

[0006]

[Problems to be solved by the device]

 However, the temperature inside the heating cylinder 22, the nozzle 6 and the nozzle tip 7 is maintained at 200 to 350 ° C. by electric heat or a heating medium, while the fixed mold 1 is heated and maintained at 50 to 100 ° C. When the injection device 100 is brought into contact with the fixed mold 1 for the injection operation, rapid heat transfer occurs from the high temperature injection device 100 side to the low temperature fixed mold 1 side, so that the injection device 100 side A temperature drop occurs, and the resin R is also lowered accordingly, so that the viscosity of the resin R is increased. If the resin R is injected as it is, the resin R is not sufficiently filled in the cavities 3 of the molds 1 and 2, and the desired temperature is not obtained. I couldn't make a molded product that would work.

In view of these problems, the tip 10 of the nozzle tip 7 is sprayed with a ceramic 10 having a low thermal conductivity, or the nozzle tip 7 is covered with the above-mentioned synthetic resin and fixed from the injection device 100 side. Attempts were made to prevent heat transfer to the die 1 side, but the following new problems arose. That is, when the ceramic 10 was sprayed, the ceramic 10 having a low thermal conductivity provided the thermal insulation effect for preventing the heat transfer described above, but the frequent contact of the nozzle tip 7 with the die resulted in the thermal insulation effect. Ceramic 10 was sometimes broken. Further, when the nozzle tip 7 is covered with synthetic resin, the synthetic resin may be removed together with the strength of the synthetic resin and the resin R attached to the nozzle 6 when the nozzle 6 is retracted. In many cases, it is necessary to reset each time, which makes handling inconvenient.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned conventional problems, in the present invention, in a nozzle for a molten material injection molding machine of an injection molding machine, the injection molding machine nozzle is composed of a nozzle and a removable nozzle mounting member. A structure with a poor heat conductor interposed between the nozzle and the nozzle mounting member.

[0009]

[Action]

 When the resin in the heating cylinder is melted and further injected into the mold, 50 to 50% from the injection device having a temperature of 200 to 350 ° C due to the presence of a poor heat conductor between the nozzle body and the nozzle mounting member. The heat transfer to the mold having a temperature of 100 ° C. is extremely reduced, and the molten resin temperature becomes stable, so that a good quality molded product can be manufactured.

[0010]

【Example】

 FIG. 1 is a front sectional view of a nozzle portion for an injection device showing an embodiment according to the present invention. Here, since the injection device is the same as the conventional example, its explanation is omitted, and only the attachment of the defective heat conductor to the tip of the nozzle according to the present invention will be described.

In FIG. 1, a synthetic resin 14, which is a poor conductor of heat, for example, a sheet of polyimide resin having a thickness of 2 to 3 mm is attached so as to cover the end face 6 a of the nozzle 6 and the nozzle tip 7. The nozzle mounting member 12 is mounted so as to press the sheet of polyimide resin as a whole, and the nozzle 6, the synthetic resin 14, and the nozzle mounting member 12 are configured to overlap each other.

The above-mentioned nozzle mounting members 12 are assembled at equal intervals to the nozzle 6 by means of screws 13 with a plate, etc., so that they will not come loose during injection. In addition, since the polyimide resin sheet 14 is interposed between the nozzle 6 and the nozzle mounting member 12, a packing-like effect is produced, and in order to strongly press the injection device against the fixed mold 1 during injection, the surface of the polyimide resin sheet 14 is Although a high pressure is applied, the molten resin R is sealed by this sheet 14, and the leakage of the molten resin R can be completely prevented. Further, even if a part of the polyimide resin sheet 14 is worn after repeated use, it is sufficient to remove the nozzle mounting member 12 from the nozzle body 6 and replace it with a new polyimide resin sheet 14 by the operation opposite to the assembling work or the like. ， Workability is improved and it is cheap.

[0013]

[Effect of the device]

 As is apparent from the above description, in the present invention, in the molten material injection molding machine nozzle of the injection molding machine, the injection molding machine nozzle is composed of a nozzle and a removable nozzle mounting member. Since a poor heat conductor is interposed between the nozzle and the nozzle mounting member, the structure is simple and the heat transfer from the injection device to the fixed mold is extremely small, and a resin of constant viscosity can be supplied to the cavity. Moreover, since the product cooling rate in the mold can be increased, high-quality molded products can be obtained and the molding cycle can be improved.

[Brief description of drawings]

FIG. 1 is a front sectional view of a nozzle portion for an injection device according to the present invention.

FIG. 2 is a front view of a conventional injection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed mold 2 Moving mold 3 Cavity 4 Sprue part 5 Heating head 6 Nozzle 7 Nozzle tip 12 Nozzle mounting member 13 Screw 14 Heat defective conductor (insulating material) 22 Heating cylinder (barrel) 23 Heater 24 Screw 100 Injection device

Claims (1)

[Scope of utility model registration request] 1. A molten material injection molding machine nozzle for an injection molding machine, wherein the injection molding machine nozzle comprises a nozzle and a removable nozzle mounting member, and a defective heat conductor is provided between the nozzle and the nozzle mounting member. A nozzle for an injection molding machine characterized by being interposed.