JP2554291B2 - Injection speed measuring method of injection molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring an injection speed of an injection molding apparatus such as a die casting machine or an injection molding machine, particularly a high injection speed when filling a cavity with molten metal or molten resin.

[0002]

2. Description of the Related Art Today, in order to manufacture a high quality injection-molded article, in a die casting machine, an injection speed at the time of filling a molten metal into a cavity is controlled by feedback control. In this feedback control,
First, the forward speed of the plunger tip or the injection cylinder is detected to detect the injection speed, and based on this detected injection speed, the opening change of the flow rate adjustment valve that sends pressure oil to the injection cylinder and the injection The setting of the pressure valve that adjusts the oil pressure for this purpose will be modified.

As a method of detecting the injection speed,
One point in the high-speed injection section is set as the measurement position, the instantaneous speed of passing through this one point or a short section range including the one point is measured, and the measured value is set as the high-speed injection speed, which is the basis of correction for the next injection. And a method of outputting a measurement timing signal from an external device such as an injection controller, and detecting the speed at the time when this timing signal is output and basing the next injection speed as a high-speed injection speed, or By calculating the average value of the specific section in the preset high-speed injection section and using it as the high-speed injection speed, the method that is the basis of the next injection, and by measuring the maximum value of the high-speed injection section as the peak speed A method based on the next injection is used, and the feedback control of the injection speed is performed based on the measured and detected value.

Also, in an injection molding apparatus for injection molding a molten resin, the high speed injection speed of the injection molding machine is similarly detected when performing the injection molding, and thus the feedback control is often performed.

[0005]

The method of determining one point as the above-mentioned measuring point and the method of measuring the injection speed by outputting a timing signal from an external device have the injection speed of only a part of the high-speed injection section next time. Since the entire high-speed injection section is controlled, there is a drawback that accurate correction control cannot be performed.

Further, the method of calculating the average value of the specific section in the high-speed injection section is affected by the overshoot at the time of changing the injection speed depending on the setting of the specific section, and is also affected by the galling or the like. Therefore, there is a drawback that it requires a lot of skill and skill to determine a specific section which is a measurement section so as not to perform unnecessary correction.

Further, the method of detecting the peak value is suitable for eliminating adverse effects such as not causing serious defects in products and devices, but it is suitable for increasing the accuracy of products. It was something I couldn't say. Therefore, the conventional speed detection method is insufficient to manufacture a high quality product, and it is difficult to perform appropriate feedback control for stably performing continuous injection of a high quality product. There was a flaw.

[0008]

According to the present invention, an injection speed is divided into a plurality of sections with a predetermined speed width, a large number of injection speeds in a high-speed injection section are measured at regular intervals, and the most measured value is included. The average of the measured values belonging to the speed section is calculated.

[0009]

[Operation] In the present invention, the injection speed is divided into predetermined speed ranges, and the speed of the range belonging to the section containing the most measurement points is used as the basis for calculating the average value. Therefore, the injection speed is relatively stable. The velocity average can be obtained from the range, and the influence of disturbance due to overshoot or galling can be reduced.

[0010]

EXAMPLE As shown in FIG. 2, an example of the present invention is a cavity 1 formed between a fixed mold 11 and a movable mold 13.
In the die casting machine for injecting the molten metal 29 from the injection sleeve 23 in FIG. 5, the moving speed when the plunger tip 25 is advanced by the injection cylinder 21 is detected by the magnet scale 27. For example, as shown in FIG. 3, the injection sleeve 2 in which a predetermined amount of molten metal 29 is injected according to the volume of the cavity 15 is injected.
The plunger tip 25 is moved forward at a low speed so that the air in 3 is first discharged, and the inside of the injection sleeve 23 is filled with the molten metal 29 injected into the injection sleeve 23 at this low injection speed. After the air inside the injection sleeve 23 is discharged by filling the inside with the molten metal 29, a predetermined position Ph
Therefore, the forward speed of the plunger tip 25 is increased to increase the injection speed, and from the position Pd at which the molten metal 29 is substantially filled in the cavity 15 to a deceleration section in which the injection speed is reduced, the molten metal 29 is filled in the cavity 15. Sometimes, a high injection speed is set so as not to cause an excessive impact on the mold or the like.

When detecting the change in the injection speed, for example, the stroke 1 at least in the high-speed injection section is detected.
In addition to detecting the velocity in mm, the detected velocity value is stored, and the injection velocity is divided into a number of sections in advance with a width Vd of 0.1 m / sec for the first velocity region. The n-th partition Vn is set as the n-th speed region from the partition V1 and each of the stored speeds is distributed to the partition of each speed region, and the number of storage speeds belonging to the first partition V1 to the n-th partition Vn is set. The largest partition is set as the specific partition Vk, and only the storage speed belonging to the area of this specific partition Vk is extracted to calculate the average speed.

A concrete method for calculating the average velocity is to first obtain an injection characteristic curve from the start of injection by calculation as shown in FIGS. 1 and 3, and the calculation of the injection characteristic curve is as follows. The moving speed of the plunger tip 25 driven and advanced by the injection cylinder 21 by the magnet scale 27 is detected, and the vertical axis indicates the injection speed and the horizontal axis indicates the time axis or the movement of the plunger tip 25 as shown in FIG. First, a graph in which the positions are graduated is created based on the detected values.

In the present embodiment, the range from the high speed switching position Ph to the deceleration command position Pd in the high speed injection section between the high speed switching position Ph and the filling completion position Pe is set as the measurement target range. The maximum speed Vmax within the range is detected, and the interval between the maximum speed Vmax and the high-speed injection lower limit value Vmin, which is an inherent value of the control system, is divided into a large number of areas having a predetermined speed width, so that the required number of pieces is equalized. The divisions are formed at intervals, and the first division V1, the second division V2, ...
...... As the nth section Vn.

Further, the detected value detected for obtaining the injection characteristic curve is used as sampling data, and the sampling data is assigned to the area range of each section in accordance with the value of each data, whereby each section is divided. By determining the number i of sampling data belonging to V1 to Vn, the number of sampling data included in the velocity region of each of the first section V1 to the n-th section Vn is counted. A section Vk having the maximum number i of data is obtained.

When there are a plurality of partitions having the same number i of sampling data and the maximum number, the partition to which the fastest speed region is assigned is selected from the partitions having the maximum number and the specific partition is selected. Let Vk. In this way, after the section Vk having the maximum number i of sampling data is obtained, the speed measurement value outside the range of the specific section Vk is deleted to obtain the specific section Vk.
The average injection speed is calculated by calculating the average of the speed measurement values in the area.

In this embodiment, the specific section Vk having a predetermined speed width that maximizes the number i of sampling data in this way.
Since the average value is calculated using the speed within the area of, the average value can be obtained from the relatively stable high-speed injection speed, and the influence of disturbance such as overshoot and fluctuation due to galling can be reduced and stable. The above feedback control can be performed.

When determining the first to n-th sections V1 to Vn, the section between the maximum speed Vmax and the high-speed injection lower limit value Vmin is divided into the required number of n sections as described above. Not only when defining the speed range Vd that is the area, but also by setting and inputting the speed range Vd that defines the area of each section, and setting within the range from the maximum speed Vmax to the high-speed injection lower limit value Vmin with the detected maximum speed Vmax as a reference. The first section V1 to the n-th section Vn may be sequentially provided with the speed range Vd.

Further, not only when each section is set on the basis of the value of the detected maximum speed Vmax, the speed area of each section is preset and input as shown in FIG. 4, and this area is set. In some cases, the injection characteristic curve may be aligned with the injection speed coordinate axis in which the defined first section V1 to n-th section Vn are defined, and the average value in the specific section Vk in which the number i of sampling data is maximum. The value of each sampling data is not averaged to calculate the average velocity when calculating, but as shown in FIG. 4, every three detection values used for calculating the injection characteristic curve, etc. As described above, the detection value for each required number is used as sampling data to determine the specific section Vk in which the number i of sampling data is maximum, and when calculating the velocity average value in the area of the specific section Vk, the sampling data is used. Fine It may be that finding the average injection speed with a detected value measured at intervals.

As described above, in this embodiment, the average speed is based on the injection speed of the portion in which the sampling data, which is the measured value, is included in a specific area and the number of which is the largest and which is relatively stable. Therefore, for example, even if the distance from the high speed switching position Ph to the injection completion position Pe is short, and as shown in FIG. This is a method that can extract and average the speed of the section that most affects the molding of the product, such as the required section near the maximum speed.

Therefore, the present embodiment is capable of detecting a stable high-speed injection speed and enabling feedback control based on this stable detection speed, and various characteristic curves. Is a method of measuring the injection speed, which allows the speed to be detected by easily corresponding to the injection speed in the injection molding set.

[0021]

Since the present invention is a measuring method for measuring a large number of injection speeds at regular intervals and obtaining the average of the injection speeds belonging to the speed region having the most measurement points, the injection speeds with various injection speed characteristics are set. In the above, it is a method of measuring an injection speed that can detect and measure a relatively stable velocity section as a basis of a controlled object and can perform stable feedback control.

[Brief description of drawings]

FIG. 1 is a flow chart showing a procedure of an embodiment according to the present invention.
Figure.

FIG. 2 is a schematic view of a die casting machine for carrying out the present invention.

FIG. 3 is a graph showing a velocity characteristic curve of injection velocity showing an example of the present invention.

FIG. 4 is a graph showing another measurement example according to another embodiment of the present invention.

FIG. 5 is a graph showing another injection velocity characteristic curve to which the present invention is applied.

[Explanation of symbols]

11 Fixed mold 13 Movable mold 15 Cavity 21 Injection cylinder 23 Injection sleeve 25 Plunger tip 27 Magnet scale 29 Molten metal

Claims (1)

(57) [Claims] 1. An injection speed is divided into a plurality of sections having a predetermined speed width, and a large number of injection speeds in a high-speed injection section are measured at a constant interval to obtain a large number of injection speeds as sampling data. The injection speed is calculated by determining the section to which the largest number of sampling data belongs among the sections of the predetermined speed width as the specific section, and calculating the average value of the injection speeds in the area of the specific section. Injection speed measurement method for molding equipment.