Injection molding apparatus and a method therefor

• US 20010019183A1
• Filed: 02/08/2001
• Published: 09/06/2001
• Est. Priority Date: 02/09/2000
• Status: Active Grant

• Current Assignee: Sony Disc & Digital Solutions Incorporated (Sony Group Corp.)
• Original Assignee: Sony Disc & Digital Solutions Incorporated (Sony Group Corp.)
• Inventors: Yoshimura, Hideaki, Kishi, Shinsuke
• Granted Patent: US 6,841,103 B2
• Time in Patent Office: Days
• US Class Current: 264/40.1
• CPC Class Codes: B29C 2045/2687 controlling the filling thereof B29C2045/2691 takes precedence
• CPC Class Codes: B29C 2945/76006 Pressure
• CPC Class Codes: B29C 2945/76257 cavity
• CPC Class Codes: B29C 2945/76381 Injection
• CPC Class Codes: B29C 2945/76505 Force
• CPC Class Codes: B29C 2945/76545 Flow rate
• CPC Class Codes: B29C 2945/76648 Sequence, e.g. the order in which operations are conducted
• CPC Class Codes: B29C 2945/76709 clamping or closing drive means
• CPC Class Codes: B29C 2945/76765 Moulding material
• CPC Class Codes: B29C 2945/76943 compare with thresholds
• CPC Class Codes: B29C 45/7653 mould clamping forces
• CPC Class Codes: B29C 45/77 of velocity or pressure of moulding material

Abstract

There is provided an infection molding apparatus capable of preventing an occurrence of over-packing which is comprised of: a pair of dies for forming a plurality of cavities therebetween; die closing devices for closing the pair of dies under a prescribed pressure; an injection device for Injecting a molten resin into respective cavities under a prescribed pressure; and a control device for controlling the die closing devices and the Injection device, and further the apparatus comprises a plurality of pressure sensors for detecting respective pressures in respective cavities, wherein the control device controls the injection device and/or the die closing devices to reduce a rate of injection of the molten resin and/or a force of closing of the dies, otherwise to stop the injection and/or the die closing operation when a pressure difference between cavities is found to be greater than a prescribed value on the basis of sensed values from the respective pressure sensors.

Claims

1. An injection molding apparatus, comprising:

at least a pair of dies provided to be openable and closable for forming a plurality of cavities therebetween when said pair of dies are closed;

die closing means for closing said pair of dies under a prescribed pressure;

injection means for injecting a molten resin under a prescribed pressure into said plurality of cavities formed between said pair of dies when said dies are closed; and

control means for controlling said die closing means and said injection means, said apparatus further comprising;

a plurality of pressure detection means for detecting a pressure in each of said plurality of cavities, wherein;

said control means controls said injection means and said die closing means in accordance with a detected value from said plurality of pressure detection means.

2. The injection molding apparatus according to

claim 1

, wherein when a pressure difference among said plurality of cavities is found to be greater than a prescribed value, said control means controls a rate of injection of the molten resin and/or a die closing force to be reduced, in accordance with the detected values from said plurality of pressure detection means.

3. The injection molding apparatus according to

claim 1

, wherein when a pressure difference among said plurality of cavities is found to be greater than a prescribed value, said control means stops the injection of the molten resin and/or application of a die closing force, in accordance with the detected values from said plurality of pressure detection means.

4. The injection molding apparatus according to any one of claims 1, 2 and 3, wherein said control means carries out its control in accordance with a program which presets injection conditions at a first molding instance in an injection molding operation.

5. The injection molding apparatus according to any one of claims 1, 2 and 3, wherein said control means controls so that a quantity of injection of the molten resin in a first molding instance in its injection molding operation becomes 1/n or less compared with a quantity of injection thereof in a second and subsequent molding instances, provided that there exist n cavities.

6. An injection molding apparatus, comprising

at least a pair of dies provided to be openable and closable for forming a plurality of cavities therebetween when said pair of dies are closed;

die closing means for closing said pair of dies under a prescribed pressure;

injection means for injecting a molten resin under a prescribed pressure into said plurality of cavities formed between said pair of dies which said dies are closed; and

control means for controlling said die closing means and said injection means, wherein;

said control means carries out its control in accordance with a program, which presets injection conditions that are effective only for a first molding instance in an injection molding operation.

7. The injection molding apparatus according to

claim 6

, wherein said control means controls so that a quantity of injection of the molten resin at a first molding instance in an injection molding operation becomes 1/n or less compared with a quantity of injection thereof at a second and subsequent molding instances, provided that there exist n cavities.

8. An injection molding method utilizing an injection molding apparatus having at least a pair of dies provided to be openable and closable for forming a plurality of cavities therebetween when said pair of dies are closed, into which a molten resin is injected, said method comprising the steps of;

detecting a pressure in each of said plurality of cavities, respectively; and

if a pressure difference between said plurality of cavities exceeds a predetermined value, reducing a rate of injection of the molten resin and/or a die closing force.

9. An injection molding method utilizing an injection molding apparatus having at least a pair of dies provided to be openable and closable for forming a plurality of cavities therebetween when said pair of dies are closed, into which a molten resin is injected, said method comprising the steps of:

detecting a pressure in each of said plurality of cavities, respectively; and

if a pressure difference between said plurality of cavities exceeds a predetermined value, stopping injection of the molten resin and/or application of a die closing force.