Injection molding machine

Patent metadata

Field	Value
Publication number	US-2021001527-A1
Application number	US-202016913388-A
Country	US
Kind code	A1
Filing date	Jun 26, 2020
Priority date	Jul 4, 2019
Publication date	Jan 7, 2021
Grant date	—

Abstract

An injection molding machine includes: a first driving device rotating a screw provided inside a heating cylinder; a second driving device moving the screw forward and backward; a metering control section configured to, by controlling the first driving device and the second driving device, to meter resin while melting the resin, and thereafter rotate the screw in reverse to thereby reduce the pressure of the resin; a first sensor unit for detecting the pressure; a second sensor unit for detecting one or more kinds of physical quantities that affect the change of the pressure; and a prediction section predicting decompressing rotation information based on the pressure detected by the first sensor unit and the one or more kinds of physical quantities detected by the second sensor unit. The metering control section controls the first driving device based on the decompressing rotation information predicted by the prediction section.

First claim

What is claimed is:

1 . An injection molding machine including a heating cylinder configured to melt resin and a screw provided inside the heating cylinder, comprising:
a first driving device configured to rotate the screw inside the heating cylinder; a second driving device configured to move the screw forward and backward inside the heating cylinder; a metering control section configured to, by controlling the first driving device and the second driving device, move the screw backward while rotating the screw forward so as to meter an amount of the resin while melting the resin, and thereafter rotate the screw in reverse to thereby reduce a pressure of the resin; a first sensor unit configured to detect the pressure; a second sensor unit configured to detect one or more kinds of physical quantities that affect change of the pressure, from the injection molding machine; and a prediction section configured to predict decompressing rotation information including at least one of a rotation angle by which the screw should be rotated in reverse after the metering in order to reduce the pressure to a target pressure and a rotation speed at which the screw should be rotated in reverse after the metering in order to keep an amount of change of the pressure per unit time at a predetermined level or lower, based on the pressure detected by the first sensor unit and the one or more kinds of physical quantities detected by the second sensor unit, wherein the metering control section is configured to control the first driving device based on the decompressing rotation information predicted by the prediction section.

2 . The injection molding machine according to claim 1 , wherein the second sensor unit is configured to detect at least one of a rotation speed of the screw, a torque of the screw, a temperature of the resin, electric current values of the first driving device and the second driving device, a position of the screw, a phase of rotation of the screw.

3 . The injection molding machine according to claim 1 , wherein the prediction section is configured to predict the decompressing rotation information based on the pressure and the one or more kinds of physical quantities detected by the first sensor unit and the second sensor unit during a period from when the screw starts rotating forward to when the screw starts rotating in reverse.

4 . The injection molding machine according to claim 3 , wherein:
the metering control section is configured to move the screw backward to a predetermined metering position while rotating the screw forward; and the prediction section is configured to predict the decompressing rotation information based on the pressure and the one or more kinds of physical quantities detected by the first sensor unit and the second sensor unit after a distance by which the screw has moved backward becomes equal to or more than half a distance between a backward movement start point and the metering position.

5 . The injection molding machine according to claim 1 , wherein:
the metering control section is configured to rotate the screw in reverse for a predetermined time, based on provisional rotation information including at least one of a predetermined rotation speed and a predetermined rotation angle, after having moved the screw backward while rotating the screw forward, and thereafter rotate the screw in reverse based on the decompressing rotation information predicted by the prediction section; and the prediction section is configured to predict the decompressing rotation information based on the pressure and the one or more kinds of physical quantities detected by the first sensor unit and the second sensor unit while the screw is rotating in reverse based on the provisional rotation information.

6 . The injection molding machine according to claim 1 , wherein:
the prediction section is configured to predict the decompressing rotation information from the pressure detected by the first sensor unit and the one or more kinds of physical quantities detected by the second sensor unit, based on a predetermined conversion formula; the first sensor unit is configured to successively detect the pressure while the screw is rotating in reverse based on the decompressing rotation information; the injection molding machine further includes: a comparison section configured to compare change of the pressure predicted based on the decompressing rotation information with actual change of the pressure when the screw is rotated in reverse based on the decompressing rotation information; and a conversion formula updating section configured to update the conversion formula so as to minimize a deviation between the predicted change of the pressure and the actual change of the pressure, based on comparison made by the comparison section.

Assignees

• Fanuc Corp

Inventors

• Asaoka Hiroyasu
• Horiuchi Atsushi
• Shimizu Kenjirou
• Nakao Haruhiko

Classifications

• B29C45/5008

  Drive means therefor · CPC title

• B29C45/50 Primary

  Axially movable screw · CPC title

• B29C45/77 Primary

  of velocity or pressure of moulding material · CPC title

• B29C2045/5096

  decompression of the moulding material by retraction or opposite rotation of the screw · CPC title

• B29C2945/7602

  Torque · CPC title