CN1307036C

CN1307036C - Control method for improving quality of extrusion injection shaping product

Info

Publication number: CN1307036C
Application number: CNB200310122027XA
Authority: CN
Inventors: 刘津平
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-12-31
Filing date: 2003-12-31
Publication date: 2007-03-28
Anticipated expiration: 2023-12-31
Also published as: CN1555973A

Abstract

Through the real-time measurement of the melt pressure in the extruder head of the extrusion-injection molding machine, it is compared with the predetermined value to adjust the backward movement speed of the melt storage device or the injection device or the position value during the backward movement, and feedback Real-time control of the melt pressure and pressure distribution in the extruder, so as to ensure the stable quality of the extruded melt and improve the quality of the final molded product.

Description

A kind of raising extrudes-control method of injection molded article quality

Technical field

The invention belongs to macromolecular material processing and forming and equipment thereof and control field, relate to a kind of raising compounding to extrude-control method of injection molded article quality.

Background technology

Extrude-injection moulding is based on traditional injection molding technique, and closing the compounding expressing technique is the novel processing technology in a step.Use this technology and can make the product that to make with traditional injection moulding, or be difficult to the product of manufacturing.In addition,, saved the intermediate link in many conventional machining process, reduced production cost because material is extruded, injection moulding one goes on foot and forms.

The work of can not turning round continuously of compounding extruder on the extruding of initial stage-injection (mo(u)lding) machine, application is restricted.European patent EP 1280648, U.S. Pat 2003038406 disclose a kind of mechanical device that can be used for addressing the above problem.The plasticizing extruder of this device and melting charge hold-up tank concentric in-line are arranged, in process of production, plasticizing extruder continuously operates, consequent melting charge enters the hold-up tank of plasticizing extruder front end through a unlimited switch valve, when reaching predefined injection volume, this switch valve cuts out, whole plasticizing extruder is moved forward by hydraulic oil cylinder driving, relies on the conducting element of plasticizing extruder inner screw front end that the melting charge in the hold-up tank is injected in the mould cavity through the switch valve that opens wide on nozzle.There are two big defectives in this mode that addresses the above problem and device: 1) action that is injected into mould cavity of the melting charge in this device will lean on the fast preceding in-migration of whole plasticizing extruder to finish, and its energy consumption is big, and control accuracy is low; 2) switch valve that is arranged on the plasticizing extruder screw front end in this device must cut out with pressure maintaining period in the melting charge injection, and plasticizing extruder is meanwhile constantly operating and constantly producing new melting charge, and can produce unexpected melt pressure and increase this moment.So loop cycle can produce bad injection molded article.

World patent WO03041940 discloses a kind of compounding injection (mo(u)lding) machine, can be used for the goods of the system of injection moulding tool different performance material.This patent has been described its hold-up tank and has been arranged on the barrel of the first end of plasticizing extruder inner screw melt zone, when the plunger advancement of the melt that the extruder continuous operation produces in the injection device that arrange the extruder bottom injected, enters hold-up tank.Melt when moving behind plunger in the hold-up tank and is continued melt extruded to screw front end with other material in extruder barrel, enter injection device again.Yet melt zone and other material that all will be pushed screw rod/barrel by the material in the what hold-up tank in each injection moulding cycle are once more met, motion forward again, therefore produce uprushing and whole barrel internal pressure distribution sudden change of melt zone material, produce the unsettled melt extrusion of quality during meeting.During but product molding that molding cycle short big at injection volume, also phenomenon under feeding may appear.

In addition, above-mentioned patent does not relate to the control method of the equipment of describing.

U.S. Pat 2003075821, German patent DE 1052244 is in order to solve the bigger problem of melt pressure fluctuation, this patent disclosure a kind of method, promptly increased by a covering device: melt pressure in the measuring tube on the tube connector between extruder and injection device, measured value and ideal value are made comparisons, by regulating the melt capacity in hold-up tank or the injection device, control the stability of melt pressure.

Summary of the invention

The present invention relates to a kind of more accurate control compounding extrude-injection (mo(u)lding) machine in the method for melt melt pressure stability in the extruder.The method that relates to be by directly extruding-measure melt pressure in real time in the cross-head of injection (mo(u)lding) machine, measured melt pressure value compares with predetermined value at any time, its difference is admitted the parameter that moves past the shift value in the journey in speed or the device behind the plunger as regulating the melt of storing in (or hold and send) device or the injection device, The whole control system constantly makes this difference towards zero development, to guarantee fusion pressure pressure stability in the extruder operation process machine.

Controlling organization involved in the present invention is that equipment melt melt holds and send extruding-injection (mo(u)lding) machine of device, that is: comprise a kind of extruder that can make melt continuously, there is one can move forward and backward and at least one with the injection device of the plunger of melt injection moulding dies cavity, one is contained in and can intermittently admits on the cross-head or the melt of dispatch melt extrusion holds and send device, the jockey that a kind of melting charge that extruder is produced imports the plunger type injection device and the two front end is connected, one is installed in the pressure sensor that can measure and export melt pressure value in the head on the cross-head, a kind of controller that can receive the pressure sensor output signal, the drive unit that send plunger motion in device and/or the injection device is held in driving, and a kind of melt holds and send plunger Stroke Displacement Transducer in the device.

Another kind of controlling organization involved in the present invention is extruding-injection (mo(u)lding) machine of a plurality of injection devices of equipment, that is: comprise a kind of extruder that can make melt continuously, at least two respectively contain one and can move forward and backward and with the injection device of the plunger of melt injection moulding dies cavity, the jockey that a kind of melting charge that extruder is produced imports the plunger type injection device and the two front end is connected, one is installed in the pressure sensor that can measure and export melt pressure value in the head on the cross-head, a kind of controller that can receive the pressure sensor output signal, drive the drive unit of plunger motion in the injection device, plunger movement travel displacement transducer in a kind of injection device.

Extruder involved in the present invention can be an any kind.

Description of drawings

Fig. 1 is that expression controlling organization involved in the present invention is that equipment melt melt holds the control schematic diagram that send the extruding of device-injection (mo(u)lding) machine.

Fig. 2 is that expression controlling organization involved in the present invention is the control schematic diagram of equipment the extruding of a plurality of injection devices-injection (mo(u)lding) machine.

The specific embodiment

To what control embodiment involved in the present invention, be described in detail as follows with reference to accompanying drawing:

With reference to Fig. 1:

Under the rotation of the screw rod that drive unit (not shown) drives drives, material is that head (30) moves towards screw tip constantly, experience is transferred, mix, the plastifying fusion process, enter the space (14) of injection device (2) by the unlimited connection mozzle (12) of switch valve (13) through the melting charge of complete plastifying fusion, and promote to move behind the plunger (15), melting charge amount until space (14) reaches the required injection of goods (and pressurize) amount, switch valve (16) opens wide simultaneously, switch valve (13) cuts out, by driving cylinder (21,22) actuation plunger (15) is injected into the mould of matched moulds (25) die cavity with the melting charge of lining, space (14), curing molding after pressurize cooling again, clamping apparatus is opened and to be ejected goods subsequently, matched moulds and repeat identical mechanical action together again with injection device, and extruder is continuous operation then.

At switch valve (13) when closing, melt hold send device (10) plunger (11) at driving cylinder ((23,24) under the effect, move on gradually according to the melt pressure that sets, the melting charge of admitting the plasticized screw extruder constantly to make stops when capacity reaches the predetermined set amount, and leans on plunger (11) at driving cylinder (23 when switch valve (13) opens wide, 24) under the effect melt held the melting charge that send in the device (10) to the whole emptyings of mozzle (12) direction, import injection device.

In whole operation, the pressure sensor (36) that is contained on the head (30) is constantly measured the interior melt pressure of head (30) and the pressure signal value is passed to controller (40) by holding wire (37), controller (40) constantly compares measured force value and predefined melt pressure value, and according to its difference situation, by holding wire (42) and control valve (52) control driving cylinder (21,22) actuation plunger (15) is injected into the mould of matched moulds (25) die cavity with the melting charge of lining, space (14), and hold when giving device (10) or injection device (2) to admit melting charge at melt, controller (40) is by holding wire (41) and control valve (51), or (52) actuation plunger (11) or (15) after move past positional value in the journey after moving speed or pilot plunger, regulate the interior melt pressure of head (30), the melt pressure value and the predetermined value that newly record are compared, and control to adjust again according to its difference situation.Circulation so repeatedly forces interior the melt pressure of head (30) to approach or waits the predetermined melt pressure value of what, thereby guarantees that the interior melt pressure of extruder is stablized in the operation.In the process, Stroke Displacement Transducer (not shown) participates in the predetermined stroke terminal point of control plunger (11,15).

With reference to Fig. 2:

Under the rotation of the screw rod that drive unit (not shown) drives drives, material is that head (30) moves towards screw tip constantly, experience is transferred, mix, the plastifying fusion process, through the melting charge of complete plastifying fusion by diaphragm valve (13) to connection mozzle (12) (A) to the space that enters injection device (2) (14), and promote to move behind the plunger (15), melting charge amount until space (14) reaches the required injection of goods (and pressurize) amount, switch valve this moment (16) opens wide, diaphragm valve (13) spacious to connect mozzle (12) (B) to, at oil pressure pipe (43,44) under the pressure differential effect, actuation plunger (15) is injected into the mould of matched moulds (not shown) die cavity with the melting charge of lining, space (14), curing molding after pressurize cooling again, clamping apparatus is opened and is ejected goods subsequently, matched moulds and repeat identical mechanical action together with injection device again, extruder is continuous operation then.

Switching valve (13) spacious to connect mozzle (12) (B) to the time, the plunger (65) of injection device (62) is at oil pressure pipe (38,39) under the pressure differential effect, move after gradually according to the melt pressure that sets, the melting charge of admitting extruder constantly to make, when capacity reaches the predetermined set amount, stop, and diaphragm valve (13) spacious to connect mozzle (12) (A) to the time, to the melting charge of the mould of matched moulds (end diagram) die cavity injection.

In whole operation, the pressure sensor (36) that is contained on the head (30) is constantly measured the interior melt pressure of head (30) and the pressure signal value is passed to controller (40) by holding wire (37), controller (40) constantly compares measured force value and predefined melt pressure value, and according to its difference situation, by holding wire (42), control valve (52) and oil pressure pipe (43,44) control actuation plunger (15) is injected into the mould of matched moulds (not shown) die cavity with the melting charge of lining, space (14), and when injection device (62) or injection device (2) admittance melting charge, controller (40) is by holding wire (41,42) and control valve (51), or (52) actuation plunger (65) or (15) after move past positional value in the journey after moving speed or pilot plunger, regulate the interior melt pressure of head (30), the melt pressure value and the predetermined value that newly record are compared, and control to adjust again according to its difference situation.Circulation so repeatedly forces interior the melt pressure of head (30) to approach or waits the predetermined melt pressure value of what, thereby guarantees that the interior melt pressure of extruder is stablized in the operation.In the process, the Stroke Displacement Transducer (not shown) of injection piston (65) or (15) participates in the predetermined stroke terminal point of control plunger (65,15).

Claims

1. A control method for improving the quality of extrusion-injection molded products, the method involved comprising: measuring the melt pressure in the extruder head of an extrusion-injection molding machine, comparing the measured value with a predetermined pressure value, and according to its The difference gives a control signal to adjust the speed of the plunger in the melt storage device or the injection device or the position value during the backward movement to obtain a stable melt pressure.

2. A control method for improving the quality of extrusion-injection molding products as claimed in claim 1, characterized in that: the clamping device of the extrusion-injection molding machine has at least two templates that can be installed with molding molds And it is a full hydraulic locking mode, a hydraulic transmission toggle locking mechanism or an electric transmission type.

3. A control method for improving the quality of extrusion-injection molded products as claimed in claim 1, wherein said extrusion-injection molding machine comprises an extruder capable of continuously producing melt, at least An injection device with a plunger that can move back and forth and inject the melt into the inner cavity of the molding mold, a melt storage device installed on the head of the extruder that can intermittently receive or discharge the extruded melt, a A connection device that makes the molten material produced by the extruder lead into the plunger type injection device and connects the front ends of the two, a pressure sensor installed on the head of the extruder to measure and output the pressure value of the melt in the head, a A controller capable of receiving output signals from a pressure sensor, a driving device for driving a plunger in a storage device and/or an injection device, and a plunger stroke displacement sensor in a melt storage device.

4. A control method for improving the quality of extrusion-injection molding products as claimed in claim 1, characterized in that: the motor-driven oil pump of the extrusion-injection molding machine is a variable or quantitative type.

5. A control method for improving the quality of extrusion-injection molded products as claimed in claim 1, wherein said extrusion-injection molding machine comprises an extruder capable of continuously producing melt, at least Two injection devices each containing a plunger that can move back and forth and inject the melt into the cavity of the molding die, a connection device that allows the molten material produced by the extruder to be introduced into the plunger injection device and connects the front ends of the two , a pressure sensor installed on the head of the extruder that can measure and output the pressure value of the melt in the head, a controller that can receive the output signal of the pressure sensor, a driving device that drives the plunger in the injection device, a Plunger movement stroke displacement sensor in injection device.

6. A control method for improving the quality of extrusion-injection molded products as claimed in claim 1, characterized in that: the injection plunger in the plunger injection device of the extrusion-injection molding machine is driven by hydraulic pressure Move back and forth.

7. A control method for improving the quality of extrusion-injection molded products as claimed in claim 1, characterized in that: the plunger in the melt storage device of the extrusion-injection molding machine is hydraulically driven before and after move.

8. A control method for improving the quality of extrusion-injection molding products as claimed in claim 1, characterized in that: the guide tube in the connecting device of the extrusion-injection molding machine is equipped with a melting The material passes through, and the on-off valve that the molten material cannot pass through when it is closed.