Injection molding machine

Patent metadata

Field	Value
Publication number	US-11524433-B2
Application number	US-201715713944-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Sep 27, 2016
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

An injection molding machine includes: a plunger provided inside a barrel and capable of moving forward and backward in an axial direction thereof and rotating about an axis thereof; a feed hole for feeding a molding material in liquid form into a front of the plunger; a packing provided on a backward side of the feed hole to prevent the molding material fed through the feed hole from flowing backward along the plunger; and a controller for controlling a retracting movement of the plunger based on pressure of the molding material fed from the feed hole to thereby perform metering. In this configuration, at least part of the feed hole is covered by a side surface of the plunger at least from start to end of the retracting movement.

First claim

What is claimed is:

1. An injection molding machine that performs molding by injecting a molding material into a mold from a nozzle arranged on a distal end side of a barrel, comprising:
a plunger provided inside the barrel and configured to move forward and backward in an axial direction thereof and rotate about an axis thereof;
a feed hole configured to allow the molding material in liquid form to be fed into a front of the plunger;
a backflow prevention member provided on a backward side of the feed hole and configured to prevent the molding material fed through the feed hole from flowing backward along the plunger; and
a controller configured to control retracting movement of the plunger based on pressure of the molding material fed from the feed hole to thereby perform metering, wherein
the nozzle is attached directly to the barrel;
the nozzle and the barrel each have a bore formed thereinside that enables the plunger to move forward and backward;
the feed hole is formed in the nozzle so as to allow the molding material to be fed into the bore formed inside the nozzle; and
the backflow prevention member is attached to the bore formed inside the nozzle or the barrel,
an outer diameter of a cylindrical portion that is a distal end portion of the plunger is greater than an outer diameter of a cylindrical portion that is a proximal end portion of the plunger,
a gap between the cylindrical portion that is the distal end portion and the bore is set to be equal to or smaller than a predetermined size,
at least part of the feed hole is covered by a side surface of the cylindrical portion that is the distal end portion of the plunger, at least from a start of the retracting movement to an end of the retracting movement.

2. An injection molding machine that performs molding by injecting a molding material into a mold from a nozzle arranged on a distal end side of a barrel, comprising:
a plunger provided inside the barrel and configured to move forward and backward in an axial direction thereof and rotate about an axis thereof;
a feed hole configured to allow the molding material in liquid form to be fed into a front of the plunger;
a backflow prevention member provided on a backward side of the feed hole and configured to prevent the molding material fed through the feed hole from flowing backward along the plunger; and
a controller configured to control retracting movement of the plunger based on pressure of the molding material fed from the feed hole to thereby perform metering, wherein
the nozzle is attached to the barrel via a nozzle adaptor;
the nozzle adaptor and the barrel each have a bore formed thereinside that enables the plunger to move forward and backward;
the feed hole is formed in the nozzle adaptor so as to allow the molding material to be fed into the bore formed inside the nozzle adaptor; and
the backflow prevention member is attached to the bore formed inside the nozzle adaptor or inside the barrel,
an outer diameter of a cylindrical portion that is a distal end portion of the plunger is greater than an outer diameter of a cylindrical portion that is a proximal end portion of the plunger,
a gap between the cylindrical portion that is the distal end portion and the bore is set to be equal to or smaller than a predetermined size,
at least part of the feed hole is covered by a side surface of the cylindrical portion that is the distal end portion of the plunger, at least from a start of the retracting movement to an end of the retracting movement.

3. The injection molding machine according to claim 1 , wherein a second hole communicating with the bore of the barrel is formed in a proximal end portion of the barrel.

4. The injection molding machine according to claim 2 , wherein a second hole communicating with the bore of the barrel is formed in a proximal end portion of the barrel.

5. The injection molding machine according to claim 1 , wherein the controller is configured to rotate the plunger during the retracting movement.

6. The injection molding machine according to claim 2 , wherein the controller is configured to rotate the plunger during the retracting movement.

Assignees

• Fanuc Corp

Inventors

• Namiki Kensuke

Classifications

• B29C45/18 Primary

  Feeding the material into the injection moulding apparatus {, i.e. feeding the non-plastified material into the injection unit} · CPC title

• B29C2945/76678

  injection piston · CPC title

• B29C2945/762

  injection piston · CPC title

• B29C2045/575

  preventing backflow of moulding material to the injection means during after-pressure · CPC title

• B29C45/77

  of velocity or pressure of moulding material · CPC title