WO2010137460A1

WO2010137460A1 - Method for creating injection speed program pattern for injection molding machine and control device for injection molding machine

Info

Publication number: WO2010137460A1
Application number: PCT/JP2010/058042
Authority: WO
Inventors: 修司合葉
Original assignee: 株式会社ソディックプラステック
Priority date: 2009-05-29
Filing date: 2010-05-12
Publication date: 2010-12-02
Also published as: JPWO2010137460A1; JP4913924B2

Abstract

Provided is a method for creating an injection speed program pattern for an injection molding machine by which good products can be continuously molded with the least amount of operation energy, by repeating a simple trial shot which does not require highly proficient judgment. Among portions in a die cavity where a flow path of a molten resin is branched or a cross-sectional area of a flow path changes stepwise, n-portions are arbitrarily selected, n being at least one; the die cavity is sectioned from a first filling section (K1) to n+1-th filling section (Kn) using the selected n-portions as boundaries; pressure upper limit values (P1, P2 ………) which are the minimum injection pressure capable of filling the respective filling sections (K1 ………) full of the molten resin are obtained; the pressure upper limit values (P1, P2 ………) obtained for the respective filling sections (K1 ………) are set to perform a trial shot for a molded product (Z); and an actual measured pattern of the injection speed when a good product is obtained is used as an injection speed program pattern (VPT) for a speed priority control.

Description

Method for creating injection speed program pattern of injection molding machine and control device for injection molding machine

The present invention relates to a method for creating an injection speed program pattern for setting a target condition for control in an injection molding machine that operates automatically by program control, and an injection speed program pattern that is created and created. The present invention relates to a control device for program-controlling an injection molding machine.

Recent injection molding machines have operating conditions such as the type of resin used, the temperature of the plasticizing cylinder, the amount of injection resin in each shot cycle, the injection pressure during the injection operation, the injection speed, and the holding pressure after completion of the injection operation. The optimum value is stored in advance in a control computer, and automatic operation is performed while performing feedback control according to the operation conditions stored in each part of the injection molding machine, so that a homogeneous product can be mass-produced.

In addition, the operation guideline of injection molding machines in recent years is based on the policy of emphasizing production efficiency such as how many products can be produced per unit time, for example, energy consumed for production per unit number. The policy is shifting to a policy that emphasizes reducing the environmental impact, such as how the amount can be reduced. This is due to changes in the social situation in which the price for the environmental load is included in the product price.

Therefore, the various operating conditions, which are the contents of the program that controls the injection molding machine, are not only required to maintain the quality of the products produced, but also injection molding with low energy consumption without shortening the service life of molds, etc. It is also necessary to meet the demand for whether the machine can be operated.

Among the various operating conditions that are the contents of the program that controls the injection molding machine, the contents of the injection conditions that control the injection process, which is the process until the molten resin is forcibly transferred from the injection cylinder into the mold cavity, are as follows: It is a technical field that has a particularly high level of attention in the industry as having a great influence on the product quality, mold life, and energy consumed in the operation of injection molding machines. Much time and effort has been devoted (see the prior art document column below).

As the control elements of the injection process from the start of injection until the required amount of molten resin is filled in the mold cavities and immediately before the pressure holding process, there are the injection speed and the injection pressure. In addition, when controlling the injection process based on either the injection speed or the injection pressure, these control elements are fixed values along the time axis or the advance position of the injection plunger or injection screw within the injection period. Pattern or time axis, or a pattern of values that change along the advance position of the injection plunger or injection screw (hereinafter, the injection conditions based on the injection speed are referred to as “injection speed program pattern”, and the injection pressure is used as the reference. The injection condition to perform is called “injection pressure program pattern”).

Generally, when controlling the injection process based on the speed feedback control based on the injection speed program pattern, since the time from the start of injection to the completion of injection is constant, the molding cycle for each shot becomes stable, and the adjacent process Can be smoothly coordinated. However, in this control method, the injection speed is maintained so as to match the injection speed program pattern regardless of the change in the injection pressure. Therefore, the overpacking is caused by the slight fluctuation of the injection speed immediately before the completion of the injection process. It is known that problems of (overfilling) and poor filling occur, causing mold breakage and product defects. Therefore, the determination of the injection speed program pattern is a work that requires difficult skills that must take into account the feedback control capability of the control unit of the injection molding machine.

On the other hand, when the pressure control of the injection process is controlled based on the injection pressure program pattern, there is an advantage that the injection pressure does not increase abnormally in the injection process, but the injection speed is ignored. Therefore, the molding cycle for each shot becomes unstable, and there is a problem inherent in using the injection pressure program pattern that the reproducibility or repeatability when performing continuous shots is poor.

An injection speed setting method has been proposed in which an injection speed program pattern can be easily formulated for the above general problem (see Patent Document 1).

In the method of the above-mentioned document, the injection pressure is set to an initial pressure value which is a fixed value on the low pressure side as an initial condition, a test shot is performed with injection pressure priority control, and the injection pressure set value is gradually set according to the filling failure of the molded product. The molding is repeated while increasing, and the average value of the actually measured injection speed that changes in the whole area of the one-shot injection process when a good product is obtained, that is, the first speed value is obtained. In actual molding, molding is performed by injection speed priority control using the injection speed program pattern of the first speed value. The reason why the injection speed priority control is used instead of the injection pressure priority control using the pressure value when a good product is obtained is that it is necessary to improve reproducibility while stabilizing the molding cycle.

However, when the injection process is controlled using the first-speed injection speed program pattern created as described above, there is a problem that wasteful operating energy is consumed in the injection process. This is because the pressure value used for the test shot for creating the injection speed program pattern is set to a high value required to fill the entire mold cavity with the molten resin. Therefore, for sprues and runners that do not require large injection pressure, the mold cavity first half, etc., the molten resin is driven at a speed higher than necessary, and wasteful energy is consumed. A large load is applied.

Further, a method has been proposed in which an injection speed program pattern is created by performing a combination of injection speed priority control in which the upper limit is controlled by a pressure value and injection pressure priority control by open control (see Patent Document 2). ).

In the above method, as an initial condition, a trial shot is performed by setting a temporary injection speed pattern that an expert expects from observation of a mold cavity and an injection pressure regulation value of one pressure value. Molding is performed by injection speed feedback control until the actually measured value reaches a set regulation value, and after reaching the regulation value, switching to injection pressure priority control by open control is continued. And the measured value pattern of the injection speed when a non-defective product is obtained by a plurality of test shots by such a method is used as the injection speed program pattern during mass production operation.

In the injection speed program pattern created by the method as described above, the pressure priority control is switched at the later stage of the injection process where the injection pressure is highest at the time of the test shot, so overpacking is prevented and the mold at the time of the test shot is It can be expected to damage or extend the life of the mold during mass production. However, in the first half of the injection process at the time of the test shot, since the speed priority control based on the injection speed pattern based on the guess of the skilled operator is performed, an objective actual measurement value based on the injection pressure value has not been detected. There is no guarantee that this condition is the best, and there is a problem that it cannot be reproduced by an unfamiliar operator.

Japanese Patent No. 2598747 Japanese Patent No. 3430189

By the way, the sprue part, runner part, gate part, and product part in the mold apparatus are different in shape and cross-sectional area, respectively, and the minimum injection pressure required to fill the molten resin is also different in the shape and cross-sectional area. Each is different. Therefore, when injection molding is performed under the injection speed condition generated in Patent Document 1, there is a portion where the molten resin flows with an injection pressure more than necessary.

Also, the shape and cross-sectional dimensions of the sprue part and runner part are often determined by the idea of the mold designer rather than by the shape and dimensions of the product part. Therefore, even if there are a plurality of mold apparatuses that mold the same product, the shape of the sprue part or the runner part and their cross-sectional dimensions may differ if the designers of the mold apparatuses are different. Therefore, in Patent Document 1, since one pressure value is set in accordance with the latter half of the filling step where pressure is increased most, the injection pressure value actually generated when the molten resin flows in the first half of the filling step, that is, the sprue portion or the runner portion. May be different for each mold apparatus. On the other hand, in Patent Document 2, since it is switched to the pressure priority control at the latter stage of the filling process in which the injection pressure is highest at the time of trial molding, the purpose is to prevent overpacking to the last. In the first half of the filling process at the time of trial molding, since the injection speed priority control is performed based on the injection speed condition, the actual speed value is not detected by the pressure priority control. The injection speed condition in the first stage of the filling process must be set by trial and error by the operator.

Therefore, the present invention provides a method for creating an injection speed program pattern of an injection molding machine capable of generating an optimal injection speed condition according to the difference in the shape and cross-sectional dimensions of the flow path in the mold apparatus, and the injection speed program pattern. An object of the present invention is to provide a control device for an injection molding machine that can be programmed and controlled based on the created injection speed program pattern.

The method of creating the injection speed program pattern of the injection molding machine according to the present invention includes at least one of locations where the shape and the flow path cross-sectional area of the flow path of the molten resin in the mold cavity change, such as branching and joining locations. Arbitrary n or more points are selected, and the mold cavity is sequentially filled with the first filling section and the second filling section from the upstream side when the molten resin is filled into the mold cavity with the selected n places as a boundary. As described above, the interval is set up to the (n + 1) th filling interval, and multiple times while increasing the injection pressure stepwise for all the filling intervals selected in any order from the first filling interval to the (n + 1) th filling interval. By carrying out the test shots for each filling section, the upper limit value of the injection pressure, which is the upper limit value of the injection pressure at which the molten resin can be almost fully filled in each filling section, is obtained and the corresponding filling section is supported. Test shot by pressure priority control in the state where the pressure change point that is the forward position of the injection screw or injection plunger is obtained, and the pressure upper limit value and pressure change point obtained for each filling section are set in the control device of the injection molding machine In this case, the measured value pattern of the injection speed is an injection speed program pattern for controlling the injection molding machine by speed priority control.

In the method of creating the injection speed program pattern of the injection molding machine, first, the section is set in the mold cavity. The section is set by visually observing the mold cavity and selecting at least one arbitrary n point from the branching point of the flow path of the molten resin and the position where the cross-sectional area of the flow path changes stepwise (n is 1). The above natural number) is performed by a method of recognizing the selected portion as a boundary and treating the front and rear of the boundary as different filling sections. Since the determination of the branching point of the flow path of the molten resin is obvious even for non-experts, this operation is easy and can be determined by the non-experts.
Here, “locations where the shape and flow path cross-sectional area of the flow path branching / merging points in the mold cavity change” are not only those where the shape of the product part or flow path cross-sectional area changes. In addition, a sprue part, a runner part, and a gate part in the mold apparatus are included, and an angle changing part of the flow path is also included. Moreover, the branch position of the flow path (the branch position when a large number of products are taken) is also included. Some products have a gate portion or the like inside the product, but these are also included. And about a product part, it is preferable that the location where the said shape differs, or the location where a flow-path cross-sectional area changes are all the locations where the shape and cross-sectional area of a product change in steps.

The determination of how many filling sections are set in the mold cavity can be determined in reverse from the required accuracy of the product manufactured by the mold, that is, objectively determined. Advanced empirical knowledge is not required. However, the accuracy of the final injection speed program pattern can be improved by setting a large number of sections in the mold cavity, but there is a relationship that the number of subsequent test shots increases. It is preferable to set the section by recognizing this. Note that the inside of the mold cavity is set to the number of filling sections obtained by adding 1 to the number of locations of the selected boundary. The set filling sections are handled in the order of the first filling section, the second filling section, and the (n + 1) th filling section in order from the upstream side when the molten resin is filled into the mold cavity.

Next, a test shot is performed for each filling section. At this time, it is arbitrary from which filling section the test shot is started. Note that the test shot performed here is not a test shot for determining the quality of a product that is generally performed, but an injection pressure at which the molten resin can be almost fully filled in each filling section of the mold cavity. This is a test shot for the purpose of seeking. Here, “full filling” refers to a state in which a specific filling section subject to a test shot is completely filled with molten resin, and therefore “almost full filling” refers to the state before full filling. The state is almost full. For example, (a) the corner of the product portion may not be completely filled, and (b) sink marks (the product surface has irregularities) may be present. The final filling of the product to the corner of the product or prevention of sink marks is performed in a pressure holding process performed following the injection process as usual.

The test shot for each filling section is performed multiple times while increasing the injection pressure step by step to obtain the upper limit value of the injection pressure at which the molten resin can be almost fully filled in each filling section of the mold cavity. The forward position of the injection screw or the injection plunger when a substantially full state is obtained in the filling section is obtained as the pressure change point. Note that whether or not the molten resin is almost fully filled in each filling section is determined by visual determination. For example, in the case of obtaining the pressure upper limit value and the pressure change point in the nth filling section, (1) injection is performed with the injection upper limit pressure higher than before, (2) when the molten resin in the mold is solidified, the mold is opened, (3) Visual determination is performed, (4) the molded product is taken out from the mold, and (5) the mold is closed (further clamped). The above is repeated until the nth filling section is almost full. Further, visual determination after the molded product (4) is taken out from the mold is also possible.

Next, in the test shot by the pressure priority control in the state where the pressure upper limit value and the pressure change point obtained for each filling section from the first filling section to the (n + 1) th filling section are set in the control device of the injection molding machine. The measured value pattern of the injection speed is used as an injection speed program pattern for controlling the injection molding machine by speed priority control. The pressure upper limit value and the pressure change point for each filling section may be set in the control device every time the test shot for each filling section is completed, or set collectively after the test shots for all filling sections are completed. Even so, the result is the same.

The injection speed program pattern finally obtained as described above is the injection speed when the injection operation is performed while changing the injection pressure for each filling section according to the pressure upper limit value set for each filling section. It can be positioned as a change pattern. That is, as long as the injection operation is executed by speed priority control based on this injection speed program pattern, it is guaranteed that the injection pressure in each filling section does not exceed the pressure upper limit value when the injection speed program pattern is obtained. It is.

The method for creating an injection speed program pattern of an injection molding machine according to the present invention is based on the basic invention described above, by actually measuring the injection speed when obtaining the pressure upper limit value corresponding to the filling section for each filling section, An injection speed program pattern can be created by connecting the actual measurement patterns of the injection speed obtained for each section.

In the case of adopting the above configuration, the trial shot is performed in an arbitrary order from the first filling section to the (n + 1) th filling section, and the pressure upper limit value corresponding to the filling section is obtained for each filling section. By measuring the injection speed, the upper limit of pressure and the pressure change point for each filling section, which are the preconditions for obtaining the injection speed program pattern, are obtained simultaneously with the completion of the test shot for the last filling section. Simultaneously with the completion of the test shot for the section, it is possible to obtain an injection speed program pattern in a state in which the actually measured injection speed pattern obtained for each filling section is connected. Therefore, it is possible to omit an injection speed program pattern creation step and create an injection speed program pattern that fits a specific mold in a short time.

The method of creating the injection speed program pattern of the injection molding machine of the present invention sequentially performs a test shot for each filling section from the first filling section to the (n + 1) th filling section for any configuration of the present invention. The initial value of the pressure upper limit value to be obtained in a plurality of test shots carried out while increasing the injection pressure stepwise in each filling section can be set as the pressure upper limit value of the immediately preceding previous filling section.

In the case of adopting the above configuration, since the test shots for each filling section are sequentially performed from the first filling section, the pressure upper limit value to be obtained by the test shot for the specific filling section is the value before the filling section. The injection speed program pattern can be created in a short time by making full use of the obvious reason that it cannot be below the upper pressure limit of the filling section of the order. In other words, the trial shot for a specific filling section can be performed by excluding the range below the upper pressure limit value of the latest previous filling section that has already been obtained.

The control device for an injection molding machine according to the present invention drives at least a setting device for setting various molding conditions, a molding condition storage unit, an actual measurement value storage unit for storing actual measurement value data for each shot, and a monitor. For each filling section of a plurality of filling sections set in the mold cavity based on the characteristics of the mold cavity used. In the test shot to be performed, the molding condition storage unit stores the injection pressure while changing the injection pressure stepwise via the setting device, and the molding condition storage unit stores the injection pressure data input via the setting device. The mechanism control unit controls the injection mechanism of the injection molding machine based on the injection pressure data sent from the molding condition storage unit, and the actual measurement value storage unit stores each when a predetermined filling state is obtained. By storing the injection pressure, the injection speed, and the position data of the injection screw or the injection plunger for each filling section, the actual value data of the injection speed through the entire filling section is created. The measured value data of the injection speed is output to the molding condition storage unit directly or via the display control unit and stored as an injection speed program pattern, and the mechanism control unit converts the injection speed program pattern to be output from the molding condition storage unit. The injection mechanism is controlled as a target.

The control device of the injection molding machine having the above-described configuration is configured for each filling section of the mold cavity by function cooperation with the setting device, the molding condition storage unit, the actual measurement value storage unit, the display control unit, and the mechanism control unit each having the above functions. An injection speed program pattern can be created from the result of the trial shot by the pressure priority control of the open system, and the injection mechanism of the injection molding machine can be controlled based on the created injection speed program pattern.

The injection speed program pattern creation method of the injection molding machine of the present invention is a method in which the shape of the flow path of the resin and the cross-sectional area of the flow path change in the mold cavity before performing the test shot for the entire mold cavity. After dividing into a plurality of filling sections at the boundary (reference) and obtaining a minimum injection pressure that can be almost fully filled with molten resin for each filling section, it was obtained by a test shot that was performed for each filling section, and then obtained A test shot is performed on the entire mold by pressure priority control with the injection pressure as a target value, and an injection speed program pattern finally required is created by actually measuring the injection speed at the time of this test shot. Therefore, it is possible to generate an injection speed program pattern when molding is performed at an optimal injection pressure corresponding to the difference in the shape and cross-sectional area of the flow path in the mold.

Since the work content of the test shot to be performed for each filling section is a simple content to be performed until the molten resin is fully filled while gradually increasing the injection pressure in the filling section to be the target of the test shot, Advanced experience judgment such as prediction of the pressure load applied to the mold is unnecessary, and even an unskilled person can reliably carry out the process without causing an accident such as damage to the mold.

The test shot process for the entire mold for obtaining the injection speed program pattern is performed by pressure priority control with the pressure upper limit value obtained for each filling section as a target value, so the pressure applied to the mold in this process is Since the set pressure upper limit value is not exceeded, it is possible to reliably prevent the mold from being damaged due to a prediction error of the pressure upper limit value at the time of the test shot.

The injection speed program pattern finally obtained is based on an objective correlation with the pressure upper limit value optimally set for each filling section of the mold cavity. In trial shots and mass production operations of molded products using as a control target, energy-saving operation of the injection molding machine and extension of the mold life can be realized.

It is control concept explanatory drawing which shows the block structure of the control apparatus used when performing the production method of the injection speed program pattern of one embodiment of this invention linked | related with an injection molding machine. It is explanatory drawing of the molded product shape | molded by the mold cavity shape made into the preparation object of the injection speed program pattern of the said one Embodiment, (a) is the front view, (b) is the side view. . It is a figure which shows the creation example of the injection speed program pattern of the said one Embodiment with the shape of a molded article (mold cavity shape) in a creation stepwise order. It is explanatory drawing which shows the injection speed program pattern of the said one Embodiment linked | related with a plunger position.

Hereinafter, a method for creating an injection molding machine control device 30 and an injection molding machine injection speed program pattern VPT will be described by exemplifying a pre-plastic injection molding machine with reference to the drawings (FIGS. 1 to 4). ). The injection speed program pattern VPT (shown in FIG. 4) created by the method of the present invention presents a unique pattern corresponding to the mold cavity of each mold used. In order to avoid this, a molded product Z (the final product part is indicated by a reference symbol Z1) molded by the mold cavity shape will be described (FIG. 2). The pre-plastic type refers to an injection molding machine in which plastic material is plasticized with a special plasticizing screw provided separately, and this is sent to the front part of the plunger, and then the plunger is advanced to inject the thermoplastic resin. It is used for molding.

The injection molding machine comprises a plasticizing part 10 for the purpose of plasticizing a resin material and an injection part 20 for the purpose of injecting the plasticized resin material into a mold cavity. They are connected at a junction 17 provided with a molten resin communication passage 16 (FIG. 1).

The plasticizing unit 10 includes a plasticizing cylinder 15 including a hopper 13 for supplying resin pellets, a screw driving device 11 that drives a screw 14 in the plasticizing cylinder 15, and a check device that controls the front-rear operation of the screw 14. 12 mag.

On the other hand, the injection unit 20 includes an injection cylinder 2B having an injection nozzle 21 attached to the tip thereof via a nozzle cylinder 2A, an injection plunger 2C provided in the cylinder 2B, an injection drive device 27 that drives the plunger 2C, and the like. Become. The main part of the injection driving device 27 is a hydraulic cylinder including an operating rod 3A, a piston 3C, and a cylinder 3B.

The injection drive device 27 incorporates a position sensor G1 for detecting the position of the injection plunger 2C and a pressure sensor G2 for detecting the injection pressure, and the operation state and injection pressure of the injection plunger 2C from the control device 30 side. The value is monitored. In the present application, the expression “position of the injection plunger” is simply the tip position of the injection plunger 2C in a strict sense.

The outline of the injection operation in such an injection molding machine is that the screw 14 in the plasticizing cylinder 15 is slightly retracted to open the communication passage 16 of the junction portion 17 that has been blocked by the tip portion of the screw 14, Molten resin is supplied from the plasticizing cylinder 15 through the communication path 16 to the injection cylinder 2B side. On the other hand, on the injection cylinder 2B side, the injection plunger 2C receives the molten resin for one shot while moving backward, and the molten resin is measured by the retraction amount of the injection plunger 2C.

After the weighing process, the communication path 16 is closed by the advance of the screw 14. Next, the injection plunger 2C is driven forward, and the molten resin received in the injection cylinder 2B is injected into the mold cavity at a predetermined injection speed. After the molten resin is completely filled in the mold cavity, that is, after the injection process is completed, the injection plunger 2C is further driven in the forward direction to apply a holding pressure necessary for the subsequent pressure holding process to the molten resin.

In the pressure-holding process, the molten resin is completely filled in the mold cavity while flowing in a small amount in the mold cavity by the pressure-holding process, and the fluidity is lost by being cooled by the mold. Product Z. When the gate 5C of the molded product Z is cut off, the final product Z1 is obtained.

The series of cooperative operations as described above in the injection molding machine are feedback controlled so as to satisfy various conditions programmed in advance by the control device 30 including a mold clamping device (not shown).

The control device 30 includes a molding condition storage unit 31, a measured value storage unit 32, a display control unit 34 that includes a measured value conversion processing unit 33, and a mechanism control unit 36 that includes a feedback control unit 35 as functional units in charge of specific functions. And a key input device as a setting device 37 and a display device 38.

A sensor group G including a position sensor G1 and a pressure sensor G2 of the injection driving device 27 is connected to the control device 30, and an information signal from the control device 30 is used to display visual information to the operator. In addition, it is connected to a driver group D including a driver for the injection driving device 27. That is, the basic operation of the control device 30 is an operation for processing the information sent from the sensor group G in relation to pre-programmed information and sending it to the driver group D or the like.

Specifically, the molding condition storage unit 31 in the control device 30 converts and stores various molding conditions and actual measurement values input from the setting machine 37. The actual measurement value storage unit 32 stores or updates the actual measurement value information from the sensor group G. The mechanism control unit 36 controls the injection driving device 27 and other various mechanisms by feedback control based on the molding conditions and the actually measured values. The display control unit 34 converts various data and outputs the converted data to the display device. The actual value conversion processing unit 33 included in the display control unit 34 converts the actual measurement value waveform of the injection speed into a step shape or a polygonal line shape. And output to the molding condition storage unit 31.

Here, the actual value of the injection speed is detected by a method of converting the actual position value sequentially sent from the position sensor G1 that detects the forward position of the injection plunger 2C into speed data with reference to the reference clock of the control device 30. The The actual measurement value of the injection pressure is detected by the pressure sensor G2 via the hydraulic pressure that drives the injection plunger 2C. Then, the injection speed and the injection pressure when the injection plunger 2C moves forward are feedback controlled by the display control unit 34 described later with the following predetermined condition as a target.

The mold cavity formed by the fixed mold 51 and the movable mold 52 of the mold 50 used as a sample in the method for creating the injection speed program pattern VPT of the present invention includes a sprue 5A, a runner 5B, a gate 5C, and a product. The convex portion 5D, the concave portion 5E, and the convex portion 5F, which are parts, have a cavity shape that communicates sequentially (FIGS. 2 and 3). Here, the sprue 5A and the runner 5B (position S0 to position S1) are the first filling section K1, the gate 5C and the first half convex part 5D are the second filling section K2, and the concave part 5E of the product Z1 and the second half convex part. The section 5F is set as the third filling section K3. Incidentally, depending on the shape of the sprue 5A, the runner 5B, and the molded product Z, it may be divided into two sections with the gate 5C as a boundary, the sprue 5A and the runner 5B may be divided into a plurality of sections, and the final product section. Z1 may be divided into a plurality of sections or divided into four or more sections. As for the number of the above-mentioned sections, at least two sections are required with respect to places having different shapes and cross-sectional areas. Dividing into two sections with the gate 5C as a boundary is advantageous when the processing accuracy of the final product part Z1 is higher than that of the sprue 5A or the runner 5B. If the sprue 5A and the runner 5B (position S0 to position S1) are referred to as the first half of the filling process, and the gate C5 and the final product portion Z1 are referred to as the second half of the filling process, they are divided into two sections, the first half and the second half. Also good.

Hereinafter, using the above-described injection molding machine and the control device 30, a test shot is sequentially performed from the first filling section K1 to the third filling section K3 to create the injection speed program pattern VPT of the present invention. A creation method will be described (FIGS. 1 to 4).

At the start of creating the injection speed program pattern VPT, the measurement value of the molten resin per shot is set in consideration of the cushion amount, and the injection time upper limit value and the injection speed upper limit value are set as limiters. Must be set in advance. The limiters are all prepared for abnormal situations, and the injection time upper limit value is to stop the operation of the injection molding machine when the injection pressure does not rise and the filling is incomplete, the injection speed upper limit value is It functions to forcibly switch the operating condition to injection speed priority control when the injection speed rises abnormally.

In the above-described pre-setting, the molten resin is almost fully filled in the sprue 5A and the runner 5B, which are the first filling section K1, while gradually raising the pressure upper limit P1 of the injection pressure via the setting device 37 of the control device 30. A trial shot is carried out until it is done (FIG. 3A). The upper pressure limit P1 applied to the first filling section K1 is the upper pressure limit when the molten resin is substantially filled in the sprue 5A and the runner 5B and the molten resin is not flowing into the second filling section K2. Thus, the position of the injection plunger 2C at that time is obtained as the pressure change point S1 between the first filling section K1 and the second filling section K2. Further, the actual measurement value V1 of the injection speed at this time is stored in the actual measurement value storage unit 32.

The pressure upper limit value P1 and the pressure change point S1 obtained in the control device 30 are set, and a test shot is performed on the gate 5C that is the second filling section K2 and the convex portion 5D in the first half of the product based on these values. (FIG. 3B). The work procedure of the test shot is the same as the test shot for the first filling section K1, but the pressure upper limit value P1 obtained for the first filling section K1 and set in the control device 30 is the initial value. Is different. As a result of the test shot, the upper limit value of the injection pressure when the molten resin is almost sufficiently filled in the gate 5C and the convex portion 5D of the product Z and the molten resin is not flowing into the third filling section K3 is the second value. The pressure upper limit P2 is applied to the filling section K2, and the position of the injection plunger 2C at that time is the pressure change point S2 between the second filling section K2 and the third filling section K3. Further, the actual measurement value V2 of the injection speed at this time is stored in the actual measurement value storage unit 32.

Next, the pressure upper limit value P2 and the pressure change point S2 are set in the control device 30, and the product intermediate portion concave portion 5E and the product rear half convex portion 5F, which are the third filling section K3, are tested based on these values. A shot is performed to obtain the pressure upper limit value P3 and the pressure change point S3 and set them in the control device 30 (FIG. 3C). The actual value V3 of the injection speed at the time when the pressure upper limit value P3 is obtained is stored in the actual value storage unit 32, and the previously measured actual values V1 and V2 of the injection speed and the pressure change points S1 and S2 are connected. An injection speed program pattern VPT connected as dots is obtained. The created injection speed program pattern VPT is output to the display device 38 via the actual measurement value conversion processing unit 33 of the display control unit 34 as necessary, and is also output to the molding condition storage unit 31 and stored therein.

Since the injection speed program pattern VPT created as described above is created under critical conditions, in order to obtain a non-defective product, it is necessary to further modify it by performing a trial shot. There can be. In this case, the already created injection speed program pattern VPT also has significance as an injection speed program pattern for a safe test shot that does not cause mold damage.

In actual molding, injection speed priority control is performed with the injection speed program pattern VPT as a tracking target. Therefore, the necessary minimum pressure upper limit values P1, P2 in the filling sections K1, K2, K3 in the stage of creating the injection speed program pattern VPT without impairing the advantage of high repetition accuracy, which is the superiority of the injection speed priority control. , P3 is reflected, the effect of extending the mold life, the effect of preventing overpacking, and the energy saving operation effect are realized. 3A, 3B, and 3C, the “actual pressure value” indicates an actual pressure value detected by the pressure sensor G2 when the test shot is performed.

Here, the created injection speed program pattern VPT can be used after being converted into a step shape or a polygonal line shape, and even in this case, the characteristics of the original injection speed program pattern VPT are greatly impaired. Absent. In addition, although a pre-plastic type injection molding machine is used to create the injection speed program pattern VPT, it may be created by an injection molding machine that directly performs an injection operation with an injection screw. The program pattern VPT can be suitably used for such an injection molding machine.

In the above-described method of creating the injection speed program pattern VPT, the test shots are sequentially performed from the first filling section K1, but the test shots may be performed in a randomly selected order. This is because by storing the test shot results for each of the filling sections K1, K2, and K3 in the control device 30, the injection speed program pattern VPT can be obtained by completing the test shot for the last filling section. In the method of creating the injection speed program pattern VPT, the injection speed is measured for each trial shot in each of the filling sections K1, K2, K3, but the pressure upper limit value P1 of all the filling sections K1, K2, K3. , P2, P3 are obtained and set, and then a test shot is performed through all the filling sections K1, K2, K3 by pressure priority control, and the actual measured values V1, V2, V3 of the injection speed at the time of this test shot are used as they are. The program pattern VPT can also be used.

Furthermore, the pressure change points S1, S2, and S3 that have the significance of causing the control device 30 to recognize the boundaries of the filling sections K1, K2, and K3 are before the injection plunger 2C reaches the pressure change points S1, S2, and S3, respectively. It can also be used by converting to the required actual measurement time. In this case, for example, in the first filling section K1, control is performed so that the obtained pressure upper limit value P1 is maintained for a period required for the plunger 2C to reach the pressure change point S1.

VPT Injection speed program pattern V1, V2 ... Actual value of injection speed S1, S2 ... Pressure change point P1, P2 ... Pressure upper limit value K1 First filling section K2 Second filling section K3 Third filling section 2B Injection cylinder 30 Controller 31 Setter 32 Actual value storage unit 34 Display control unit 36 Mechanism control unit Z Molded product Z1 Product

Claims

At least one or more arbitrary n locations are selected from the locations where the shape and flow path cross-sectional area of the flow path of the molten resin in the mold cavity change, such as branching and joining locations, and the selected n locations are selected. As a boundary, the mold cavity is sequentially set from the upstream side when the molten resin is filled into the mold cavity to the n + 1 filling section like the first filling section and the second filling section,
By performing a plurality of test shots while increasing the injection pressure stepwise for all the filling sections selected in any order from the first filling section to the (n + 1) th filling section, for each filling section The pressure upper limit value that is the upper limit value of the injection pressure at which the molten resin can be almost fully filled in each filling section is obtained, and the pressure change point that is the advance position of the injection screw or the injection plunger corresponding to each filling section is obtained,
The injection molding machine uses the speed priority control to measure the injection speed measured value pattern at the time of the trial shot by the pressure priority control in the state where the pressure upper limit value and the pressure change point obtained for each filling section are set in the control device of the injection molding machine. A method for creating an injection speed program pattern for an injection molding machine, characterized in that an injection speed program pattern is used for program control.
The injection speed program of the injection molding machine is measured by measuring the injection speed when determining the upper pressure limit value corresponding to the filling section for each filling section, and connecting the measured value pattern of the injection speed obtained for each filling section. 2. The method of creating an injection speed program pattern for an injection molding machine according to claim 1, wherein the pattern is a pattern.
Test shots for each filling section are sequentially performed from the first filling section to the (n + 1) th filling section, and the pressure upper limit value to be obtained in a plurality of test shots performed while increasing the injection pressure stepwise in each filling section. 3. The method for creating an injection speed program pattern for an injection molding machine according to claim 1, wherein the initial value is set to the pressure upper limit value of the immediately preceding filling section.
At least a setting device for setting various molding conditions, a molding condition storage unit, an actual measurement value storage unit for storing actual measurement value data for each shot, a display control unit for driving a monitor, and various types of injection molding machines A mechanism control unit that feedback-controls the mechanism,
Molding conditions while changing injection pressure step by step through a setting device in a test shot performed for each filling section of multiple filling sections set in the mold cavity based on the characteristics of the mold cavity used The molding condition storage unit outputs the injection pressure data input via the setting device to the mechanism control unit, and the mechanism control unit is configured to output the injection pressure data sent from the molding condition storage unit. By controlling the injection mechanism of the injection molding machine, the measured value storage unit stores the injection pressure, the injection speed, and the position data of the injection screw or injection plunger for each filling section when a predetermined filling state is obtained. Create measured value data of injection speed throughout the entire filling section,
The actual measurement value storage unit outputs the actual measurement value data of the injection speed through all the created filling sections to the molding condition storage unit directly or via the display control unit and stores it as an injection speed program pattern. A control apparatus for an injection molding machine, wherein an injection mechanism is controlled with an injection speed program pattern output from a molding condition storage unit as a target.