CN100493883C - Injection speed-pressure switching and pressure keeping controller and method for electric injection molding machine - Google Patents

Injection speed-pressure switching and pressure keeping controller and method for electric injection molding machine Download PDF

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CN100493883C
CN100493883C CNB021596557A CN02159655A CN100493883C CN 100493883 C CN100493883 C CN 100493883C CN B021596557 A CNB021596557 A CN B021596557A CN 02159655 A CN02159655 A CN 02159655A CN 100493883 C CN100493883 C CN 100493883C
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pressure
firing rate
switching
injection
control unit
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CN1511693A (en
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刘兴昌
简御伟
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Industrial Technology Research Institute ITRI
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Industrial Technology Research Institute ITRI
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Abstract

The injection speed-pressure switching and pressure keeping controller has one switchable loop switch, so that the servo motor driving the injection machine can be switched between the closed position loop control and the closed pressure loop control fast and smoothly to control the optimal injection filling and pressure keeping process. In addition, by means of setting one adjustable forward parameter and one reduction of the injection shaft before switching, the injection speed-pressure switching may be trimmed to reach optimal injection speed-pressure switching parameter, optimized pressure keeping effect and raised quality of formed plastic product.

Description

Electric injection molding machine firing rate-pressure switches and the holding pressure control device and method
Technical field
The invention relates to a kind of electric injection molding machine firing rate-pressure and switch and the holding pressure control device and method, particularly about a kind of can be accurately and adjust the control device and the method for optimal firing rate-pressure switching characteristic easily
Background technology
Be used for making in a large number the injection machine of plastic products, no matter what its moulding material is, employed injection device is outer to be that plunger type or screw, mold closing mechanism are that joint formula or direct press type or drive source are fluid pressure type or electrodynamic type, and the pressure control in its injection process is the key factor of the final plastic products quality of influence.For quality problem such as the common chill mark of general plastic products, buckling deformation (Warpage and Distortion), burr (Flash), flash (Bleeding), cavity or insufficient fills, majority is because in filling or the pressure maintaining period, and pressure is not controlled well and caused.With Fig. 4 A to Fig. 4 E is example, what it showed in regular turn is locked mode, injection, pressurize, cooling, the demoulding step of fluid pressure type screw injection molding machine, variation and its transformational relation from the force value in each stage of injecting step, be closely related with the quality of plastic products, especially the switching pressure of the injection of Fig. 4 B, Fig. 4 C and packing stage and switching position (injection shaft position) are most important.If switching position too early may cause insufficient fill, switch and then the flash phenomenon might take place too late, if hypertonia easily causes the current mark of product during switching, pressure transient during as if switching (for example switch speed changes excessive) then may make pressure change the sharp-pointed irregularity curve of appearance; Simultaneously, switching position and switching pressure have also determined the size of dwell pressure, for being used for the raw material that compacting dissolves, to increase the pressure maintaining period (Fig. 4 C) of manufactured goods (plastics) density, if sticking to mould appears in the excessive plastic products that then easily cause of dwell pressure, cause the phenomenon of demoulding difficulty, but also the plastic products residual stress is increased, burr or bleed defective appear, when serious even mould may be strutted; Otherwise if dwell pressure is too small, then plastic products will shrink warpage or cavitation, be difficult to reach quality requirements equally.This shows that importance and its adjustment of injection switching characteristic are difficult for accurately; If be example with Fig. 5 again, can more clearly find out pressure controlled where the shoe pinches, Pm curve among the figure is the pressure curve of screw rod metering zone (Metering Zone) in the expression injection machine, the pressure curve of She Dinging just, the Pn curve is represented the pressure curve that injection nozzle (Nozzle) is terminal, the Pg curve is the pressure curve of die cavity (Cavity) arrival end, the Pc curve then is the pressure curve of die cavity end, because due to the die cavity internal flow pressure loss, the value of Pc curve is lower than the value of Pg curve, t1 to the t3 stage is the injection molding process stage among the figure, the interior pressure of die cavity this moment will increase sharply, the pressure control that the user promptly sets in this stage, and t3 to t4 is a packing stage, the pressure of pressurize is subjected to the injection pressure and switching pressure of previous stage, the position, the speed influence, the force value of pressurize also will determine the effect of pressurize, final t4 to the t5 stage then is a cooling stage, and plastic products will solidify gradually this moment, and will stay small amount of residual pressure as shown in the figure in the die cavity.
In sum, what as seen each position pressure changed in the process of injection molding is rapid, and the importance of carrying out pressure control and filling-pressurize switching, on the general processing procedure for the adjustment of this control with handoff parameter, rely on processing procedure engineer's experience fully, the processing procedure engineer will change process parameter or carry out the inspection of board control accuracy according to the quality of moulded plastic products, and the method obviously is difficult to reach the volume production demand of stable control and good reproducibility.With existing fluid pressure type injection machine 30 shown in Figure 6 (driving) with hydraulic motor 32, its method of operating is with resistance scale (Potential Meter) or optics chi stroke to be measured in injection process, at any time measure the position of injection shaft 35 at injection process, when the position of this injection shaft 35 reaches predefined firing rate-pressure and switches (V-P Switching) location point, make injection machine 30 switch to packing stage from packing stage, the control accuracy of the method can change because of each injection, because it is all identical when the position of injection shaft 35 is not the per injection moulding, its value can be because of inertia, along with the firing rate of the latter end of per injection and difference, and different along with 30 service times of injection machine and number of times, the process parameter of fluid pressure type injection machine 30 also will change (the quality of hydraulic oil for example to some extent, operating temperature etc.), this has a strong impact on the accuracy and repeatability of above-mentioned control, and then also will significantly reduce the quality of plastic products.
For more new-type electric injection molding machine, it is as shown in Figure 7 with the drive source of electrodynamic type servo motor 42 as injection machine 40, by an AC servo controller 43 and servo motor 42, it is with high-precision position, speed control and the conforming characteristic of controlling of height, finish the demand of firing rate-pressure switching and holding pressure control, also have concurrently simultaneously energy-conservation, advantages such as cleaning and operation peace and quiet, it is better than fluid pressure type injection machine 30 really with the holding pressure control effect that the firing rate of the injection machine 40 of this type-pressure switches, the control method that it adopts generally is to carry out the control of pressure loop circuit with a pressure control device, and injection molding process pressure and dwell pressure are maintained a predefined appropriate value.For example United States Patent (USP) the 5th, 154, No. 935 cases, invented a comparator (Comparator) as shown in Figure 8, compare at goal pressure curve and actual pressure in user's input value control module 51, also this comparative result is imported in servo circuit 53, the servo motor 55 that connects injection shaft 54 is carried out pressure loop circuit control, adjust suitable injection/dwell pressure by the connection of two outside changeable circuit switchings 52; Though this existing electric injection molding machine control method can solve the shortcoming of fluid pressure type injection machine, can't overcome the problem on the volume production.Because this device 50 only can carry out pressure loop circuit control, can't carry out the planning of firing rate and injection shaft position, also can't be with the method for firing rate-pressure switching controls, from the smooth-going packing stage that switches to of injection stage, choosing of its switching position is difficult to reach the most suitable and more sane, and the relevant switching characteristic parameter except pressure also is difficult for adjusting, in addition, the changeable circuit switching 52 of this existing apparatus 50 is that design is outside hardware, the reaction time of its switching command is longer, the switch speed of home loop also will be slower, certainly will cause misalignment and the delay controlled, be difficult to meet the demand that industrial circle is maked rapid progress.
Summary of the invention
For overcoming the shortcoming of prior art, the object of the present invention is to provide a kind of electric injection molding machine firing rate-pressure that is easy to adjust firing rate-pressure switching characteristic to switch and the holding pressure control device and method.
Another object of the present invention is to provide a kind of electric injection molding machine firing rate-pressure that can accurately choose firing rate-pressure switching position to switch and the holding pressure control device and method.
A further object of the present invention is to provide a kind of respond well electric injection molding machine firing rate-pressure of pressurize of plastic products that makes to switch and the holding pressure control device and method.
Another purpose of the present invention be to provide a kind of home loop can be smooth-going and the firing rate of electric injection molding machine apace-pressure switch and the holding pressure control device and method.
In order to achieve the above object, electric injection molding machine firing rate provided by the present invention-pressure switches and the holding pressure control device comprises: driving control unit, be connected with the motor that can drive this electric injection molding machine injection shaft, to drive, to control the motion of this injection shaft, comprising speed control; The Numerical Control unit, be connected with this driving control unit by switchable circuit switching, comprising positioner and the pressure controller that can connect with this circuit switching, with switching by this circuit switching, make this Numerical Control unit and this driving control unit form loop circuit, a position and control the switching of controlling with a pressure loop circuit, the switching of the injection process of this injection machine and pressure maintaining period just; And pressure sensitive unit, be used for detecting the true pressure of this injection shaft, and this true pressure value fed back in this Numerical Control unit, wherein when this Numerical Control unit and this driving control unit form the control of loop circuit, a position, this Numerical Control unit can carry out firing rate-pressure switching controls to this injection machine according to the true pressure value that this pressure sensitive unit fed back, can in the least significant end moderating process of this injection shaft, ask for optimal firing rate-pressure switching position thus, with under optimal firing rate-pressure handoff parameter, switch this circuit switching and form pressure loop circuit control.
Electric injection molding machine firing rate proposed by the invention-pressure switches and the holding pressure control method, can be used in one firing rate-pressure switching and the holding pressure control device, this device comprises a driving control unit that is connected with injection shaft and a Numerical Control unit, the step of this method comprises: this injection machine is carried out the injection planning of multistage firing rate and the pressurize planning of multistage pressure, and behind the final stage firing rate of this injection planning, according to the true pressure of this injection shaft, make the firing rate of this injection shaft slow down; Position X when the firing rate of injection shaft is reduced to zero is made as firing rate-pressure and switches set point, and sets one firing rate-pressure and switch observation D in advance; Switch the circuit switching in this Numerical Control unit, make this Numerical Control unit and this driving control unit form the control of loop circuit, a position; To this Numerical Control unit input position order, make this injection machine finish the action of injection of planning according to the injection planning of setting; Make the site error amount e between this Numerical Control unit judges true injection shaft position this moment and the X point, and judge whether site error amount e is less than or equal to this and switches observation D in advance, if, then carry out the switching of firing rate-pressure, if not, then carry out the adjustment of optimal firing rate-pressure handoff parameter, and after adjustment, carry out the switching of firing rate-pressure; And switch circuit switching in this Numerical Control unit, make this Numerical Control unit and this driving control unit form pressure loop circuit control, wherein, when the true pressure that is detected is too high, increase the D of observation in advance that firing rate-pressure switches, to reduce the pressure after firing rate-pressure switches, make it become optimal switching pressure; When detect to such an extent that true pressure is crossed when low, reduce the position quantity that firing rate-pressure switches set point, to improve the pressure after firing rate-pressure switches, make it become optimal switching pressure; When this Numerical Control unit and this driving control unit formed the control of pressure loop circuit, this Numerical Control unit was promptly according to pressurize planning input pressurize order, the pressurize action that this injection machine is finished planned.
Above-mentioned optimal firing rate-pressure handoff parameter comprises optimal switching position, time, pressure and the injection speed value etc. when firing rate-pressure switches, and the numerical value of this optimal firing rate-pressure handoff parameter is to decide according to user's setting, can judge according to user's injection demand and its rule of thumb; Wherein, when above-mentioned control device judges that site error amount e switches in advance observation D greater than this, the optimal firing rate that is carried out-pressure handoff parameter adjustment is the true switching pressure that detects by an external pressure sensitive unit, it is too high or too low looking this true pressure, can be by for example adjusting observation D in advance or switching the mode of set point X, in the fast process of leniently convicting somebody most of this injection shaft, ask for an optimal firing rate-pressure switching position, to avoid the not good plastic products quality decline problem that causes of handoff parameter.
Therefore, electric injection molding machine firing rate of the present invention-pressure switches and the holding pressure control device and method, it is the decelerating phase before injection molding process will be finished, firing rate-the pressure that is undertaken by the user switches fine setting, accurately adjust firing rate-pressure handoff parameters such as switching position, to obtain preferable pressurize effect; Simultaneously, because this switchable circuit switching is that design is in this Numerical Control unit, therefore its home loop can carry out a smooth-going and change action apace, and has the high DYN dynamic control characteristic of control result repeatability, can solve the product quality problem that existing control device is caused.
Description of drawings
Fig. 1 is the schematic diagram that injection parameters is set example in the preferred embodiment of the present invention;
Fig. 2 is the control device schematic diagram of preferred embodiment of the present invention;
Fig. 3 is the control method flow chart of control device shown in Figure 2;
Fig. 4 A to Fig. 4 E is the injection moulding schematic flow sheet of general injection machine;
Fig. 5 is each position pressure history figure in the process of injection molding of general injection machine;
Fig. 6 is the side view of existing fluid pressure type injection machine;
Fig. 7 is the side view of existing electric injection molding machine; And
Fig. 8 is a United States Patent (USP) the 5th, 154, the electric injection molding machine pressure control device schematic diagram of No. 935 cases.
The specific embodiment
Embodiment
Electric injection molding machine 40 used in the present invention is as shown in Figure 7, utilize servo motor 42 as drive source, and via belt 44 or gear mechanism promotion driving screw 45, plastics are expelled to carry out pressurize, cooling forming in the mould 46, firing rate in this injection stage-pressure switches and holding pressure control, and is very big for the influence of the product quality after the moulding.The firing rate that the present invention proposes-pressure switches and holding pressure control device 1 promptly is to be used on the SERVO CONTROL of this type injection machine, accurately to ask for process parameter such as switching point position, pressure and speed.For describing preferred embodiment of the present invention in detail, below promptly setting example by the injection parameters of Fig. 1 explains, this injection parameters is at injection and packing stage, be set at three sections firing rate controls and three sections dwell pressure controls respectively, the setting of hop count and numerical value is not limited only to this graphic example, should decide on injection machine user mode and user's demand.Generally set about about five sections (in the shot filling circulation) greatly for the hop count of firing rate and pressure, because the not segmentation if adopt omnidistance constant speed filling, it is excessive to consume energy, and makes plastic products produce quality problems such as overlap.Setting shown in Figure 1 is expression, carry out the plastics injection molding process with three sections firing rate V1, V2, V3 at first in regular turn, wherein the switching point of firing rate V2, V3 is respectively X1, the X2 place in the injection shaft position, the design of this firing rate size is to decide according to user's demand, just if firing rate is too high, its shear heat will be burnt plastics, thereby influence the lustrous surface of plastic products; If firing rate is low excessively, then may make loading time long and easily produce the cold joint seam; In addition, draw back owing to injection shaft will be subjected to inertia effects in injection process, so the injection shaft position of abscissa is to turn right bigger and bigger.Design of the present invention is when the position of injection shaft arrives the B point, and its firing rate begins to reduce, and increases the elasticity of carrying out firing rate-pressure handoff parameter fine setting.To set injection machine in this example and locate to carry out firing rate-pressure switching at position S point (position S=X3+D), wherein, the D value is the observation in advance that expression firing rate-pressure switches, this numerical value is to be preestablished or finely tuned during the course by the user, to look actual state control switching position point, X3 then is the set point that switches of firing rate-pressure (but have only when D=0, X3 is only actual switching point); Then, after the injection shaft switching enters packing state, promptly mould is carried out as shown in the figure three sections holding pressure control of P1, P2, P3, its pairing dwell time is respectively T1, T2, T3, its effect is the plastics that compacting dissolves, and the contingent contraction behavior of compensation plastics is in principle when the dwell time is longer, its pressure transmission will be comparatively complete, thereby can reduce the shrinkage factor of plastic products volume; It promptly is the control command of control device of the present invention that the control of Fig. 1 is set, and its numerical value can be decided on experience and injection demand by the user.
The preferred embodiment of electric injection molding machine firing rate of the present invention-pressure switching and holding pressure control device 1, can inject control according to setup parameter shown in Figure 1, this control device is as shown in Figure 2, comprise a numerical controller 10 and a servomotor drive 20, this comprises that the servomotor drive of a current controller and positioner is to electrically connect with the servo motor (not icon) of this injection machine and injection shaft, simultaneously, have three controllable loop circuit contact CC in this numerical controller, DD, EE, make this servomotor drive 20 controllably change the circuit closing contacts of itself and this numerical controller 10, control with a pressure loop circuit and form the control of loop circuit, a position respectively, simultaneously, include a positioner and a pressure controller in this numerical controller 10 in addition, respectively servo motor is carried out position and pressure control, also design an observer in the present embodiment, this observer is to be connected with a pressure sensor that can detect the injection shaft true pressure, when switching, firing rate-pressure carries out the judgement of switching position decision, wherein, this position, pressure, speed, current controller be can be respectively according to user's position, pressurize, speed, current order is deducting the loop circuit control of the laggard line correlation of its true feedback quantity; Therefore, when injection machine carries out the injection molding process process, contact EE will be communicated with contact CC, make servo motor carry out the control of loop circuit, position, this stage is according to predetermined control parameter (position command) shown in Figure 1, carry out the planning of movement locus by initial injection position to position X3 whole process, and one fixedly in sample time, import a corresponding position quantity to this positioner according to position command, finish until the omnidistance position command input of being planned, this loop circuit, position control can be controlled the accuracy of positional precision, simultaneously, because of the control of the firing rate of injection shaft also is designed to speed loop circuit control, so the velocity control accuracy of servo motor also can reach easily, guarantee injection molding process in the stage its Position Control accurately with the stablizing of speed control; After finishing three sections firing rate controls shown in Figure 1, the injection position that sets should be at position X3, the actual injection shaft position often this default X3 point of no show (factor that influences the actual injection shaft position includes the firing rate size, injection shaft inertia, loading time, plastics inertia etc.), to produce a site error e between the two, observer in the numerical controller 10 will can be observed this site error value e at this moment, and switch in advance observation D according to this predefined firing rate-pressure and judge whether directly to carry out firing rate-pressure and switch (size of looking e and D determines), perhaps optionally finely tune, for example switch to holding pressure control in advance to avoid dwell pressure high excessively according to the relevant handoff parameter of true pressure value adjustment that this pressure sensor detected.Because the present invention is set with the planning (the B point of Fig. 1) that a firing rate slows down when switching, therefore its switch speed adjustment that can between V3 to 0, elect, there are abundant elasticity and time to finely tune according to its rule of thumb and real conditions, in the hope of an optimum and the most sane switching position for the user; Then, when injection machine and after switching to packing state through parameter fine setting, contact EE in the numerical controller 10 will be communicated with contact DD, and become to open circuit with contact CC, make system carry out pressure loop circuit control, the control mode of servo motor will switch to speed command by position command this moment, and the speed command of servo-driver 20 will determine according to the pressure controller in the numerical controller 10, the pressurize order that its input value will equal to preestablish input (is P1 shown in Figure 1, P2, P3) the institute's actual pressure value that detects and feed back that deducts pressure sensor, finish (T1 until the dwell time, T2, T3), finish injection molding flow process; This control device 1 is by the design of a changeable contact and observer, can carry out the switching of control of loop circuit, position and the control of pressure loop circuit, and can carry out the fine setting of one firing rate-pressure handoff parameter easily, accurately to try to achieve preferable switching position, simultaneously, because this changeable contact (CC, DD, EE) is to design in the hardware of controller, its home loop can have a smooth-going and switch speed fast, reaction time is also shorter, can reach preferable control characteristic.
The firing rate of the control device 1 of present embodiment-pressure switches and the holding pressure control method can be with flowcharting shown in Figure 3, it is after injection stage begins, set at step S10 according to imposing a condition of Fig. 1, at first carry out the injection planning of a multistage firing rate, just set to making a track between the switching set point X3 that sets at initial injection position, simultaneously the B after terminal velocity V3 sand off lights, injection shaft is done a deceleration to be set, till up to speed being zero X3 point, importing one at last again and set to switch and shift to an earlier date observation D; Equally at step S15, at packing state work one multistage pressurize planning as shown in Figure 1; Also the EE contact in the control device is communicated with the CC contact, to form the control of loop circuit, position at step S20; Step S25 begins to import each section firing rate position command, and carries out the injection molding process action; And, judge whether this predefined omnidistance position command is all finished in the decision block of step S30; Can enter step S35 after finishing, detect this moment the actual injection shaft position with the site error e of predetermined X3 position; The decision block of step S40 will judge whether the position error e is less than or equal to this predefined observation D in advance, if "Yes", then just carry out firing rate-pressure switches in this injection shaft position, firing rate-pressure switching point is X3 point shown in Figure 1 and adds this site error value e at this moment, this switching position will be smaller or equal to the position S point of icon, and enters the packing state of step S50 after switching; If the result of determination of step S40 is a "No", then need to carry out the trimming movement of one firing rate-pressure handoff parameter at step S45, this step is decided by the true pressure that pressure sensor detects, the visual demand of user and the rule of thumb are adjusted (for example changing the D value of setting), in this step, because after latter end firing rate V3 finishes (position B), the firing rate of injection shaft promptly begins to slow down, therefore the user will have abundant elasticity and time to finely tune, after obtaining a preferable switching pressure (switching position), enter step S50 again; Step S50 interrupts script EE, CC cut-in point, then connects EE, DD contact, to form the control of pressure loop circuit; And carry out Fig. 1 institute predefined dwell pressure loop circuit at step S55 and control, import each section pressurize order to finish pressurize; And after judging among the step S60 that pressure maintaining period finishes, promptly finish all injection moulding flow processs; This control method can be by the switching of loop contact, in injection molding process and pressure maintaining period, carry out the control of position and pressure loop circuit respectively, execution graph 1 default control parameter, simultaneously, also can switch the deceleration design and the setting of observation D in advance of preceding injection shaft by entering pressurize, make the user under more abundant elastic condition, accurately adjust to required handoff parameter and switching position point.
In the above-mentioned injection molding process process, when all position commands are all imported, and the firing rate of injection shaft is when V3 reduces speed now, if the site error amount e that observer drew greater than predefined D value, represents this moment and nonideal switching state, the user, processing procedure engineer for example, can carry out the adjustment of firing rate-pressure handoff parameter at actual state, its method of adjustment can be decided injection molding demand and actual state according to the user, and its amount trimmed then can be according to the rule of thumb.
To propose one at the foregoing description herein and switch the implementation method of parameter adjustment: the user can set as shown in Figure 1 an X3 point position in advance, this is exactly that firing rate-pressure switches set point, actual switching point when just the D value is zero, it is the position of expression firing rate injection shaft when being zero, because switch speed is easy to produce the discontinuous phenomenon of creeping when being zero, and the also often imperfect switching pressure of this pressure (because this moment, switch speed changed excessive), therefore, still need and set one firing rate-pressure and switch observation D in advance, this D value is used to the usefulness of finely tuning.When numerical controller has given all position commands, and after finishing action of injection, if site error e is greater than this D value, then can be according to true pressure value that pressure sensor detected as adjusting foundation, if the switching hypertonia of this moment, can strengthen this setting D value, injection shaft can be switched with a lower desired pressure in advance, hence one can see that, the setting of D value can influence the amount trimmed size of switching position, how to change and set value with fine setting D, can be by the user according to actual detected pressure and the required desirable difference of switching pressure, rule of thumb rule is done a judgement in firing rate V3 reduces to the process of firing rate 0, switches pressure to finely tune it, parameters such as Position And Velocity; Otherwise if the true pressure value that pressure sensor detects is low excessively, hope will be switched pressure and be heightened, then can readjust and set the position that X3 is ordered, this position is adjusted backward (in the axis of abscissas of Fig. 1, positional value being turned down),, switched pressure thereby improve with time and the position that postpones to switch; Just the above only is a kind of parameter method for trimming, the visual actual conditions of user at firing rate from stage that V3 begins to descend, look the actual injection demand and use other method of adjustment, to change and to obtain preferable switching pressure, Position And Velocity, improve the filling of plastics and the pressurize quality of plastic products.
In sum, electric injection molding machine firing rate of the present invention-pressure switches and the holding pressure control device and method, can make the decelerating phase of processing procedure engineer before filling will be finished, carry out firing rate-pressure and switch fine setting, can be accurately and adjust firing rate-pressure handoff parameters such as switching position easily, obtain preferable pressurize effect; Simultaneously, it is one smooth-going and switch reaction speed fast that its home loop has, also have control repeatability height concurrently and control the effect that the result is not subject to machine or such environmental effects such as service time and number of times, can promote the quality of plastic products volume production really, to solve the problem of existing control device.

Claims (14)

1, a kind of electric injection molding machine firing rate-pressure switches and the holding pressure control device, it is characterized in that, this electric injection molding machine firing rate-pressure switches and the holding pressure control device comprises:
Driving control unit is connected with the motor that can drive this electric injection molding machine injection shaft, to drive, to control the rotation of this injection shaft, comprising speed control;
The Numerical Control unit, be connected with this driving control unit by switchable circuit switching, comprising positioner and the pressure controller that can connect with this circuit switching, with switching by this circuit switching, make this Numerical Control unit and this driving control unit form the loop circuit, position and control the switching of controlling with the pressure loop circuit, the switching of the injection process of this injection machine and pressure maintaining period just; And
Pressure sensitive unit is used for detecting the true pressure of this injection shaft, and this true pressure value is fed back in this Numerical Control unit,
Wherein when this Numerical Control unit and the control of this driving control unit formation loop circuit, position, this Numerical Control unit can carry out firing rate-pressure switching controls to injection machine according to the true pressure value that this pressure sensitive unit fed back, can in the least significant end moderating process of this injection shaft, ask for optimal firing rate-pressure switching position thus, with under optimal firing rate-pressure handoff parameter, switch this circuit switching and form pressure loop circuit control.
2, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that this optimal firing rate-pressure handoff parameter is firing rate-pressure optimal switching position, time, pressure and the injection speed value when switching.
3, electric injection molding machine firing rate as claimed in claim 2-pressure switches and the holding pressure control device, it is characterized in that the numerical basis user's of this optimal firing rate-pressure handoff parameter setting and deciding.
4, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that, also comprise observer in this Numerical Control unit, detecting the site error value e of this injection shaft,, compares and the alternate position spike that draws site error value e and being an injection shaft position that sets at the user and its actual position.
5, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that this positioner is used for accepting position command, and carries out the control of loop circuit, position according to the position quantity of this driving control unit feedback.
6, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that this pressure controller is used for accepting the pressurize order, and carries out the control of pressure loop circuit according to the size of the pressure of this pressure sensitive unit feedback.
7, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that, this speed control is used for accepting speed command, and according to the size of speed of feedback, and in this driving control unit, carry out the control of speed loop circuit.
8, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that, also comprise current controller in this driving control unit, this current controller is used for accepting current order, and according to the size of electric current of feedback, and in this driving control unit, carry out the control of electric current loop circuit.
9, electric injection molding machine firing rate as claimed in claim 1-pressure switches and the holding pressure control device, it is characterized in that, the motor that this driving control unit connects is a servo motor.
10, a kind of electric injection molding machine firing rate-pressure switches and the holding pressure control method, uses arbitrary described firing rate in the claim 1 to 9-pressure to switch and the holding pressure control device, it is characterized in that the step of this method comprises:
This injection machine is carried out the injection planning of multistage firing rate and the pressurize planning of multistage pressure, and behind the final stage firing rate of this injection planning,, make the firing rate of this injection shaft slow down according to the true pressure of this injection shaft;
Position X when the firing rate of injection shaft is reduced to zero is made as firing rate-pressure and switches set point, and sets firing rate-pressure and switch observation D in advance;
Switch the circuit switching in this Numerical Control unit, make this Numerical Control unit and this driving control unit form the control of loop circuit, position;
To this Numerical Control unit input position order, make this injection machine finish the action of injection of planning according to the injection planning of setting;
Make the site error amount e between this Numerical Control unit judges true injection shaft position this moment and the firing rate-pressure switching point, and judge whether site error amount e is less than or equal to this and switches observation D in advance, if, then carry out the switching of firing rate-pressure, if not, then carry out the adjustment of optimal firing rate-pressure handoff parameter, and after adjustment, carry out the switching of firing rate-pressure; And
Switch the circuit switching in this Numerical Control unit, make this Numerical Control unit and this driving control unit form the control of pressure loop circuit,
Wherein, when the true pressure that is detected is too high, increase the D of observation in advance that firing rate-pressure switches,, make it become optimal switching pressure to reduce the pressure after firing rate-pressure switches; When detect to such an extent that true pressure is crossed when low, reduce the position quantity that firing rate-pressure switches set point, to improve the pressure after firing rate-pressure switches, make it become optimal switching pressure; When this Numerical Control unit and this driving control unit formed the control of pressure loop circuit, this Numerical Control unit was promptly according to pressurize planning input pressurize order, the pressurize action that this injection machine is finished planned.
11, electric injection molding machine firing rate as claimed in claim 10-pressure switches and the holding pressure control method, it is characterized in that this optimal firing rate-pressure handoff parameter is firing rate-pressure the most suitable switching position, time, pressure and the injection speed value when switching.
12, electric injection molding machine firing rate as claimed in claim 11-pressure switches and the holding pressure control method, it is characterized in that the numerical basis user's of this optimal firing rate-pressure handoff parameter setting and deciding.
13, electric injection molding machine firing rate as claimed in claim 11-pressure switches and the holding pressure control method, it is characterized in that the step of the most suitable firing rate of this adjustment-pressure handoff parameter can be carried out in the moderating process behind the latter end firing rate that this injection shaft is planned in advance.
14, electric injection molding machine firing rate as claimed in claim 13-pressure switches and the holding pressure control method, it is characterized in that this method of adjusting optimal firing rate-pressure handoff parameter is can be according to injection shaft true pressure that external pressure sensitive unit detected and determine.
CNB021596557A 2002-12-30 2002-12-30 Injection speed-pressure switching and pressure keeping controller and method for electric injection molding machine Expired - Fee Related CN100493883C (en)

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CN102431136B (en) * 2011-09-16 2014-11-05 广州市香港科大霍英东研究院 Multi-phase batch process phase dividing method based on multiway principal component analysis method
CN102555180B (en) * 2012-02-10 2014-01-22 浙江大学 Injection and pressure maintaining switching control system and method for injection molding machine based on nozzle pressure
CN103640194B (en) * 2013-12-26 2016-06-08 宁波恩瑞德机电科技有限公司 A kind of Intelligent injection machine and injecting method thereof
CN110553152B (en) * 2019-09-06 2020-10-30 郑州畅威物联网科技有限公司 Pressure maintaining detection method and system for gas conveying pipe network

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