JPS60135224A - Kneading method in injection molding machine - Google Patents

Abstract

PURPOSE:To obtain uniform plasticization, by successively repeating the retraction of a screw while rotating said screw in a kneading direction and the advance while rotating the same to the opposite direction during a stand-by period up to the next time injection. CONSTITUTION:When a metering process is initiated, the driving of a servo motor 15 is stopped while a servo motor 10 is driven to rotate a screw 1 to the direction opposite to a right-handed screw direction. The molding material supplied from a hopper is brought to a plasticized state by friction heat caused by the heat of a heater and the kneading action due to the rotation of the screw 1. In this case, pressure increases as the molten material sent into the leading end part of the screw 1 increases but the servo motor 15 is driven every when said pressure reaches definite pressure or more to rotate a worm 18 to a right- handed screw direction and the screw 1 is retracted to the direction opposite to that shown by the arrow A. That is, the screw 1 is rotated and retracted while difinite back pressure is applied and this driving is performed until the screw 1 exceeds a metering point.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application and Prior Art The present invention relates to a method for mixing molding materials in an injection molding machine.

The method of kneading the molding material in a conventional injection molding machine is that after the screw moves forward to inject the molten molding material, the screw rotates back and plasticizes the molding material through the crosstalk action to achieve a constant injection amount. A measuring process is being carried out, but after the measuring process is completed and before the next injection process, there is a cooling process for the molded product, a mold opening process, a mold clamping process, etc.
The problem is that because the screw is stopped and the process is on standby, the temperature of the molten molding material becomes uneven.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for mixing a molding material in an injection molding machine, which eliminates the above-mentioned drawbacks, allows uniform plasticization of the molding material, and allows sufficient mixing. .

Structure of the Invention The present invention performs injection by advancing a screw in the axial direction, applying back pressure to the screw, and rotating the screw in the opposite direction to the screw thread direction to perform kneading while retreating to a weighing point and weighing. In an injection molding machine that performs this, until the injection welding method is determined, the screw is sequentially retracted due to cross-wire and moved forward by rotating in the opposite direction to the rotation at the time of cross-wire, to prevent cross-wire. This is a kneading method in an injection molding machine in which injection is performed from a measuring point during injection.

EXAMPLE Below, examples of the present invention will be described in detail based on the drawings. The figures do not show an example of carrying out the method of the present invention, and a screw 1 is provided with a screw head 2 at the tip. , a screw shaft 5 having a spline shaft portion 3 and a cylindrical rack portion 4 at its rear end is provided, a support portion 6 is provided at the rear end of the screw shaft 5, and the support portion 6 is connected to a base 7. An actuating gear 9 is rotatably supported on the spline shaft portion 3 and has a spline hole 8 that engages with the spline shaft portion 3 .

The servo motor 1O for rotating the screw 1 has an integrated detector 11, and the motor shaft 13 of the servo motor 10 is rotatably supported by a support 12 at the tip and meshes with the operating gear 9. A driving gear 14 is integrally fixed. Further, the servo motor 15 for moving the screw 1 in the axial direction has a detector 16 integrally, and the servo motor 1
The motor shaft 17 of No. 5 is pivotally supported at its tip by the support 12,
A worm 18 that engages with the cylindrical rack portion 4 is integrally provided.

Therefore, when the servo motor 10 is driven, the motor shaft 13 rotates, and the driving gear 1 integrated with the motor shaft 13 rotates.
4 also rotates, and the drive gear 9 meshes with the drive gear 9.
The screw 1 integrated with the spline shaft 3 that engages with the spline hole 8 rotates. Further, when the servo motor 15 is driven, the motor shaft 17 rotates, the arm 18 integrated with the motor shaft 17 rotates, and the worm 18 engages with the arm 18 of the cylindrical rack. By pressing the part 4, the screw 1 is moved in the axial direction along the spline shaft part 3 and the spline hole 8.

Next, the crosstalk method of the present invention using the above 4M configuration will be described. Now, the injection has finished, the metering process has started, and the IC is triggered. The drive of the speed motor 15 is stopped, and the speed motor 1O is driven to rotate the screw 1 in the opposite direction to the right direction. Then, the molding material supplied from the hopper (not shown) is heated by the heater (not shown) and the screw 1.
It becomes plasticized due to the frictional heat caused by crosstalk caused by the rotation of the wire. As the molten material fed into the tip of the screw 1 increases, the pressure increases, and each time the pressure exceeds a certain level, the motor 15 is driven to turn the screw 18 into a right-handed screw. direction, and the screw 1 is sequentially retreated in the direction opposite to the arrow A. In other words, the screw 1 is rotated and retreated while applying a constant back pressure, and this drive is performed until the screw 1 exceeds the 1tffi point. Next, when the screw passes the measuring point, the servo motor 10
is reversed, the screw 1 is rotated in the right-handed direction, and the servo motor 15 is also reversed, the worm 18 is rotated in the opposite direction to the right-handed direction, and the screw 1 is advanced in the six directions of arrows. The plasticized molding material stored at the tip is returned along the waveform of the screw 1, and some of it is mixed with the solid molding material.The screw 1 is advanced to an appropriate position. Then, the direction of rotation of the servo motors 10 and 15 is reversed again, and the screw 1 is moved backward while mixing the wires as before.

Such an operation, that is, an operation in which the screw 1 is rotated backward in the cross-contact direction and rotated forward in the opposite direction to the cross-contact direction is sequentially repeated during the standby period until the next injection. and,
At the time of injection, set screw 1 to the measuring point position,
The drive of the servo motor 10 is stopped and the servo motor 15 is
is driven, the arm 18 is rotated in the opposite direction to the right-hand screw, and the screw 1 is moved in the direction of the arrow 6 to perform indexing.

When the injection is completed, kneading and weighing are performed while waiting until the next injection as described above.

In the example described in F, the screw 1 was moved back while kneading to a position beyond the metering point immediately after injection.
Retract screw 1 while kneading, then rotate screw 1 in the opposite direction during kneading.

The screw 1 may be moved forward, and then the screw 1 may be moved backward and forward while avoiding repeating operations, and then moved back to a measuring point, and injection may be performed from there.

Effects of the Invention As described above, the method of kneading the molding material in the injection molding machine of the present invention is to knead the molding material in the injection molding machine of the present invention. The molding material is plasticized by sequentially repeating the forward movement while rotating in the opposite direction, and the injection is performed from the autovolume point, so that the molding material is well kneaded and uniform plasticization can be obtained. In particular, as the screw moves forward while rotating in the opposite direction to the cross-wire direction, the molten molding material is mixed with the solid molding material, which improves heat conduction and makes cross-wire easier, improving the wear resistance of the screw. can be improved. In addition, since the crosstalk continues until the next injection, the plasticization becomes more uniform and the melting temperature becomes more uniform.

[Brief explanation of drawings]

The figure is a partially cutaway front view of an embodiment of the present invention. 1...Screw, 2...Screw head, 3.
... Spline shaft part, 4... Cylindrical rack part, 5...
・Screw shirt 1~. 6... Support part, 7... Base, 8... Spline hole, 10.15... Servo motor, 14... Drive gear, 18... Worm. Patent applicant Fanuc Co., Ltd. Agent Patent attorney Tsukasa Takemoto Matsu (one idiot)

Claims (3)

[Claims] (1) Injection molding in which injection is performed by advancing the screw in the axial direction, back pressure is applied to the screw, and the screw is rotated in the opposite direction to the screw thread direction to mix lines while retreating to the measuring point and measuring. In the injection machine, the problem with the injection wave of the index welding method is to repeatedly move the screw backward due to cross-contact lines and to move it forward by rotating it in the opposite direction to the rotation during kneading. A crosstalk method in an injection molding machine that performs injection. (2) The crosstalk method in an injection molding machine according to claim 1, wherein the drive source for rotating the screw is a servo motor. (3) The kneading method in a single-mouth molding machine according to claim 1 or 2, wherein the screw is retracted to a position beyond the measuring point to perform kneading.