JPS649177B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for setting operating conditions for an injection molding machine.

(Prior Art) The first injection molding machines are required to be more precise and automated.

However, electromagnetic proportional valves are used to control the speed or pressure during the mold clamping, mold opening, or injection operations of injection molding machines, and when setting various operating conditions, it is necessary to A current output is provided to the electromagnetic proportional valve or the like. For this reason, it is extremely difficult to obtain a linear relationship between the control value and the actual execution value of injection speed or pressure due to the flow characteristics of the valve. This will result in a misalignment.

This discrepancy between the actual execution value and the execution target value means that the conditions cannot be set as intended, precision molding cannot be performed, and adjustment is difficult. This also poses a problem in terms of centralized control and production management.

In order to eliminate this kind of damage, we use a control method to match the actual execution value with the execution target value.
There is closed-loop control, which allows high control settings, but it is expensive and the control system is complicated, so it is difficult to use in general-purpose machines.
Open loop control is generally used.

Conventionally, in order to set operating conditions such as speed or pressure to desired conditions in the open-loop control, in order to know what kind of relationship exists between the control numerical value and the intended execution target value, it is necessary to set the desired operating condition in advance. This is done by displaying the relationship between the control values and the actual execution values in a graph or table, and using this to find the control values that will cause the desired operating conditions to be achieved.

(Problems to be Solved by the Invention) However, the above operating condition setting method has the following problems.

It is difficult to know the desired control amount intuitively, and when molding one mold with multiple molding machines, there are slight differences in characteristic values between each molding machine, so it is difficult to know the desired control amount intuitively. It is necessary to reset the operating conditions even between molding machines, and if the electromagnetic proportional valve that controls the operating conditions of the molding machine is replaced, the operating conditions must be reset again, which increases the number of settings. Combined with this, the setting work is cumbersome, and furthermore, errors may occur due to misreading of graphs etc. by the operator making the settings, making it difficult to expect highly controlled molding and making it difficult to achieve further automation. This has become a hindrance.

Furthermore, it takes a considerable amount of time to create the graph or table, and the amount of deviation between the actual execution value and the execution target value may occur due to changes in the type of hydraulic fluid or oil temperature in hydraulic drive systems. If the ratio of In addition, the time required to create graphs and tables is not constant, which poses a problem in terms of production control.

The present invention has been made in view of the above-mentioned difficulties, and its purpose is to facilitate the adjustment of control values and the setting operation for desired molding conditions, and to make open-loop control almost the same as closed-loop control. The object of the present invention is to provide a method for setting operating conditions that enables equivalent control accuracy and further refines and automates injection molding.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes the following configuration.

That is, in a method for setting operating conditions for an injection molding machine that adjusts a control value such as a valve opening degree in a control unit and an actual value of a controlled object such as an injection speed according to the control value, the control value is sequentially changed. Measure each actual execution value of the controlled object according to each control value,
Set an execution target value of the controlled object that has a proportional relationship with the control numerical value, find each actual limit numerical value corresponding to the actual execution value that is equal to the execution target value corresponding to each control numerical value, and calculate each control numerical value and its equivalent. Each actual control value is stored in a storage device, and when a control value is input to the control unit, the actual control value corresponding to the input control value is retrieved from the storage device, and the retrieved actual control value is The present invention is characterized in that the drive unit is actuated based on the control numerical value to cause the execution value of the controlled object to match the execution target value.

(Example) Hereinafter, a case where a preferred example of the present invention is applied to the injection speed will be described in detail based on the accompanying drawings.

FIG. 1 shows the relationship between injection speed and time. When the injection cylinder starts moving forward, the injection speed curve passes through part A, which is a transient response part during the initial rise, and reaches part B, where the speed is constant. D, which is constant speed for a short time
section, and then reaches section E, where there is a sudden stop and bounce at the end of the stroke.

In this example, when measuring the injection speed,
Focusing on part B of the injection speed curve where the speed is constant for a relatively long period of time, we measure the travel time of the injection cylinder in a fixed section using a position detector without using an expensive tachometer generator etc. Thus, the moving speed of the injection cylinder was measured and taken as the actual actual value of the injection speed. Note that it is desirable that the section B be constant over a section as long as possible, and it is necessary to know in advance how long the section A is.

FIG. 2 shows a configuration diagram of a device for setting the injection speed. In the figure, 1 is an injection piston of an injection cylinder, and 2 is an electromagnetic directional valve. 3 is an electromagnetic proportional valve that controls the flow rate of hydraulic oil;
It is connected in the middle of a pipe connecting the injection piston 1 and the electromagnetic directional control valve 2.

Reference numeral 4 denotes a position detection device for detecting the position of the screw in the injection cylinder, into which a detection signal from a position sensor attached to the screw is input.

Reference numeral 5 denotes a position setting device, which includes a plurality of position setting parts 5a, 5b, 5c...5g, 5h, 5i for setting the speed switching position or stop position of the screw.
Consists of. Note that the respective distance intervals of the position sensors corresponding to the position setting units 5a...5i are known in advance.

6 is a CPU, which performs desired arithmetic processing and control.

In addition, the position setting device 5 via the input section 7
Further, the detection device 4 is connected to the position detector 8, and the electromagnetic proportional valve 3 is connected to the electromagnetic proportional valve output section 9.
The electromagnetic directional control valve 2 includes an electromagnetic directional control valve output section 1
0 to the CPU 6, respectively.

11 is a ROM in which a predetermined program is written in advance. Also, 12 is a storage device.
It is a RAM that stores predetermined measurement results and the like, and is connected to a battery 13 to hold this memory. This ROM11, RAM12 is CPU6
It is connected to the.

14 is a speed setting device for setting the injection speed, and is connected to the CPU 6 via the input section 7.

15 is a group of operating switches for the injection molding machine, among which an adjustment start switch 15a and a setting start switch 15b are connected to the CPU 6 via a switch input section 16.
connected to.

A method of setting the injection speed using the apparatus configured as described above will be explained.

By turning on the adjustment switch 15a,
The program written in the ROM 11 causes the molding machine to perform the following operations.

The output to the electromagnetic direction switching output section 10 of the electromagnetic directional control valve 2 is continued until the position input from the position detection device 4 via the position detection section 8 matches the position of the specific position setting section 5a in the position setting device 5. The injection piston 1 is moved by the output.

The forward speed of the injection piston 1 depends on the valve opening of the electromagnetic proportional valve 3, which is a control value, that is, the flow rate of the hydraulic oil.

Therefore, first, the valve opening degree (minimum valve opening degree) of the electromagnetic proportional valve 3 is set so that the forward speed of the injection piston 1 set by the speed setting device 14 becomes the minimum speed, and the The electromagnetic directional control valve 2 is energized. Then, the injection piston 1 moves forward in a speed pattern as shown in FIG.

Then, the moving speed of the injection piston 1 is measured by measuring the moving time between predetermined position setting parts in the position setting device 5. Note that the first section in the position setting device 5, for example, the position setting section 5a
The section from 5c to 5c may correspond to section A shown in FIG. 1, so it will be ignored. As a result, the moving speed of the injection piston 1 is measured for the part B in FIG. 1 where the moving speed of the injection piston 1 is constant.
When the speed setter 14 is set to the minimum speed, that is, the actual execution value of the injection speed corresponding to the minimum valve opening of the electromagnetic proportional valve 3, which is a control value, can be known.

By automatically changing the valve opening degree of the electromagnetic ratio series valve 3, which is a control value, at a predetermined ratio, and measuring each injection speed, which is an actual execution value corresponding to each control value, as described above. As a result, a curve as shown by point X in FIG. 3 is obtained. It is desirable that the number of X points, that is, the data of the actual execution value, be as detailed as possible.

However, as shown by the X-point curve in FIG. 3, no proportional relationship is obtained between the control value and the actual execution value. Therefore, as shown by the solid line in Figure 3, the solid line connecting the origin and the actual execution value when the maximum valve opening is 99%, which is the maximum value of the control value, becomes the execution target value that has a proportional relationship with the control value. .

Next, each actual control numerical value corresponding to the actual execution value that is equal to the execution target value corresponding to each valve opening degree, which is each control numerical value, is determined, and each control numerical value and each actual control numerical value corresponding thereto are stored in the RAM 12. do.

For example, in Figure 3, when the control value is 20%, an injection speed of 20 mm/sec is the execution target value that satisfies the proportional relationship, but the actual execution value is 5.
mm/sec. Therefore, when looking at the control value indicating an injection speed of 20 mm/sec, the control value of 35% is the corresponding actual control value. Therefore, when a table is created in a specific area of the RAM 12 and the control value is given as 20% by the speed setter 14, the actual control value is
An output corresponding to 35% is outputted from the electromagnetic proportional valve output section 9.

Similarly, create a table in RAM 12 in which each control value corresponds to each actual control value so that the control value and the injection speed, which is the actual execution value, have a proportional relationship as shown by the solid line in Figure 3. . When this creation is completed, it is the end of the series of operations from when the adjustment start switch 15a is turned on, and this work is automatically performed. Note that it is desirable to notify the coordinator of this termination using a lamp, buzzer, etc.

In addition, if the ratio of deviation between the actual execution value and the execution target value does not fundamentally change, such as when replacing the electromagnetic proportional valve 3, the set value is 99%.
By simply adjusting the injection speed at the time to the injection speed before replacement, the measured and memorized values before replacement can be used as they are.

To set the injection speed to a desired molding condition, after turning on the setting start switch 15b, the speed setting device 14 is set at the position where the injection speed to be set is displayed.

In addition, in the above-mentioned embodiment, the storage section
RAM12 was used, but the RAM is not limited to this, as long as it can be written and read.Also, although the injection speed has been shown as an example, injection pressure or other actuators of the injection molding machine, such as mold clamping, mold It can also be effectively implemented at speeds such as opening.

(Effects of the Invention) In this way, according to the present invention, when adjusting so that the control value and the actual execution value are in a proportional relationship, the adjustment operator can automatically make the adjustment by turning on the adjustment start switch. The adjustment work is easy, the time required for adjustment is short, and the time can be known in advance.

In addition, when setting the molding machine to the desired molding conditions, it is possible to obtain a proportional relationship between the control value and the actual execution value, so the setting operator can set it intuitively. The setting work can be performed extremely easily without any errors caused by the operator.

Moreover, the setting is easy, and adjustment work and setting work can be done in a short time, making it easy to manage production, and further automation can be achieved through centralized control.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of drawings]

The figures show preferred embodiments of the present invention, in which FIG. 1 is a time-injection speed curve, FIG. 2 is a block diagram of a device for setting the injection speed, and FIG. 3 is a control value-injection speed curve. Part A...Rising part, Part B...Constant speed part, Part C...Rising part during shifting, Part D...Constant speed part, Part E...Stroke end part, 1...Injection piston, 2
...Solenoid directional valve, 3...Solenoid proportional valve, 4...
Position detection device, 5...Position setting device, 5a...5
i...Position setting section, 6...CPU, 7...Input section,
8...Position detection section, 9...Solenoid proportional valve output section, 1
0...Solenoid directional valve output section, 11...ROM,
12...RAM, 14...Speed setting device, 15...
Operation switch section, 15a...adjustment start switch,
15b...Setting start switch, 16...Switch input section.

Claims (1)

[Scope of Claims] 1. A method for setting operating conditions for an injection molding machine that adjusts a control value such as a valve opening degree in a control unit and an execution value of a controlled object such as an injection speed according to the control value, comprising: Measure each actual execution value of the controlled object according to each control numerical value by changing the numerical value sequentially, set the execution target value of the controlled object that has a proportional relationship with the control numerical value, and set the execution target value corresponding to each control numerical value. Each actual control value corresponding to an actual execution value equal to An injection characterized in that an actual control value corresponding to the inputted control value is retrieved from the storage device, and a drive unit is operated according to the retrieved actual control value to make the execution value of the controlled object match the execution target value. How to set operating conditions for a molding machine.