JPH0698658B2 - Method and apparatus for detecting operating state of injection molding machine - Google Patents

Description

The present invention relates to a method and apparatus for detecting an operating state of an injection molding machine when simultaneously detecting a plurality of physical quantities related to an operating state during a molding cycle.

[Conventional technology]

Generally, an injection molding machine performs molding in a predetermined molding cycle, and at this time, confirms the operating state, confirms the quality of the molded product,
The physical quantity related to the operation state during the molding cycle is detected for the purpose of searching for the optimum molding condition.

Conventionally, when detecting such a physical quantity, a fixed sampling time is set and the value of each physical quantity is detected for each sampling time. However, since the physical quantity in the molding cycle includes a rapidly changing section (high-speed operation section) and a gently changing section (low-speed operation section), it is necessary to detect the operating state of the rapidly changing section with high accuracy. When the sampling time is set to be short, the number of sampling points increases remarkably, which eventually causes a problem of increasing the capacity of the storage device, increasing the size of the entire device, and increasing the price. In particular, a plurality of physical quantities are detected simultaneously. In some cases it becomes a serious problem.

Therefore, the present applicant already disclosed in Japanese Patent Laid-Open No. 63-114620, continuously detects the pressure, and sequentially detects the physical quantity related to the operating state at the time when the detected pressure changes by a predetermined constant pressure, and When a fixed time is set and the pressure does not change within the fixed time, the physical quantity at the time when the fixed time has elapsed is detected, and the operating state is detected with high accuracy, and necessary and optimal detection is performed. We proposed a method for detecting the operating state of an injection molding machine that sets points, optimizes the storage capacity, and reduces the size and cost of the device.

[Problems to be Solved by the Invention]

By the way, the molding cycle in the injection molding machine, in particular, the injection screw speed Vs, the injection ram pressure Pi and the mold internal pressure Pm from the start of injection to the end of injection usually have the characteristics shown in FIG. , Pi, Pm), the time and degree of occurrence of the abrupt change section and the gradual change section vary greatly among the physical quantities.

Therefore, even if the conventional operating state detection method described above is applied to, for example, the injection ram pressure Pi and the injection screw speed Vs and the mold internal pressure Pm at the obtained detection point are simultaneously detected, the injection ram pressure Pi becomes gentle. In the changing sections Ta and Tb, the injection screw speed Vs and the mold internal pressure Pm change abruptly, so that highly accurate detection cannot be expected.

Although the above-mentioned conventional operation state detection method can be applied to each physical quantity individually, the control system is required to correspond to each physical quantity, resulting in a significantly complicated configuration.
Moreover, since the detection time points for each physical quantity are different, the relative detection accuracy is also reduced.

An object of the present invention is to provide a method for detecting an operating state of an injection molding machine and an operating state detecting apparatus for carrying out the method, which solves the problems existing in the related art.

[Means for Solving the Problems]

The operation state detection method according to the present invention, in detecting a plurality of physical quantities related to the operation state of the injection molding machine at the same time by sampling, means a sampling time (interval) in advance.
The same shall apply hereinafter)) Ts and predetermined sampling variations dx1, dx2 ... dxn for each physical quantity are set, and each physical quantity is detected at the same time, and the detected variation quantity dk1, dk2 of one of the physical quantities is set.
... dkn reaches the sampling change amount dx1, dx2 ... dxn or the sampling time Ts, whichever is earlier, whichever is earlier, and the values K1, K2 ... Kn and time of each physical quantity at the sequentially occurring sampling points t was detected at the same time.

In addition, the operation state detection device 1 according to the present invention includes sensors S1 and S2 that detect a plurality of physical quantities related to the operation state of the injection molding machine.
... Sn and a predetermined sampling variation dx for each physical quantity
1, dx2 ... dxn change amount setting device 2, time setting device 3 setting a predetermined sampling time Ts, sensor S1 ...
The detected change amount dk1 of one of the physical quantities detected from the sampling change amount dx1 ... or the sampling time Ts, whichever comes first, is taken as the sampling point, and the physical quantity of each physical quantity at the sampling points is sequentially generated. .. and the time t are detected at the same time.

[Action]

According to the operation state detecting method (or the detecting device 1) of the present invention, first, the change amount setting unit 2 sets predetermined sampling change amounts dx1, dx2 ... Dxn for each physical quantity.
Further, the time setter 3 sets a predetermined sampling time Ts.

On the other hand, during the molding cycle, the sensors S1, S2 ... Sn simultaneously detect each physical quantity, and the detection control unit 4 monitors the detected physical quantity. Then, the detection control unit 4 detects (samples) the value K1 of each physical quantity and the time t at that time when the detected variation dk1 ... Of any physical quantity reaches the sampling variation dx1. If the detected change amount dk1 of each physical amount reaches the sampling change amount dx1 ... before reaching the sampling time Ts, the value K1 of each physical amount at this point
... and time t are detected (sampled).

Therefore, if the detection is repeated at the sampling points that occur sequentially, all the abrupt change sections in each physical quantity can be detected with high accuracy.

〔Example〕

Next, preferred embodiments according to the present invention will be described in detail with reference to the drawings.

First, in order to clarify the present invention, a schematic configuration of an injection molding machine will be described with reference to FIG. In the figure, the injection molding machine indicated by the symbol M is roughly classified into a machine base 11, a direct pressure type mold clamping device 12 installed on the machine base 11, and a movable mold 13a mounted on a mold mounting surface of the mold clamping device 12. And a fixed mold 13b, and a mold 13 and an in-line screw type injection device 14 installed on the machine base 11, which constitute a known injection molding machine. Also,
In addition to incorporating the molding machine controller 15 in the machine base 11,
The operation state detection device 1 according to the present invention is equipped.

Next, the operation state detection device 1 and its peripheral configuration will be described with reference to FIGS. 1 and 2.

First, the mold clamping device 12 is provided with a mold clamping pressure sensor S4 for detecting hydraulic pressure during mold clamping and a movable platen position sensor S7 for detecting the position of the movable platen 21 on which the movable mold 133a is mounted. Further, the mold 13 has an in-mold resin temperature sensor S8 that detects the temperature of the resin filled in the mold cavity, an in-mold pressure sensor S2 that detects the resin pressure in the mold cavity, and a mold that detects the mold temperature. A mold temperature sensor S5 is attached. Further, the injection device 14 has a heating cylinder 22.
A heating cylinder temperature sensor S6 for detecting the temperature, a screw position (speed) sensor S1 for detecting the screw position (speed), and an injection ram pressure sensor S3 for detecting the oil pressure at the time of injection are additionally provided.

Each of these sensors S1 to S8 is connected to the slave CPU 33 via amplifier units 25 to 32 having functions such as conversion, correction, amplification, and A / D conversion as necessary. In addition, slave CPU33 is RAM3
The main CPU 35 is connected to the main CPU 35 via a display device 36, an external storage device 37, and a setting unit 40 described later, and the molding machine controller 15 is connected to the main CPU 35.

FIG. 1 shows only the main part of the operating state detection device 1 in an extracted manner. In the figure, 4 is a detection control unit. The detection control unit 4 includes the slave CPU 33, the RAM 34, and the main CPU 35 described above, and the sensors S1 ... Are connected via the amplifier units 25 ... And the molding machine controller 15 is connected. Furthermore, the display device 36 using a CRT, a plasma display, a liquid crystal display or the like via the RAM 38,
A recording device 39 such as an XY recorder and a printer, and the external storage device 37 that can use a floppy disk, an IC card, etc. are connected. On the other hand, the setting unit 40 is connected to the detection control unit 4. According to the present invention, the setting unit 40 includes a change amount setter 2 for setting a predetermined sampling change amount dx1 ... And a time setter 3 for setting a predetermined sampling time Ts, and a detection unit for setting (selecting) a physical quantity to be detected. Equipped with a physical quantity setting device.

Next, an operation state detection method according to the present invention including the function of the detection control unit 4 will be described.

First, a physical quantity to be detected, for example, a screw speed, a mold internal pressure, and an injection ram pressure are set in the detected physical quantity setting device in the setting unit 40. In addition, the physical quantity,
That is, the optimum sampling variations dx1, dx2, dx3 for the screw speed, the mold internal pressure, and the injection ram pressure are set, and the sampling time Ts is set in the time setting device 3.

On the other hand, when the injection molding machine operates, the operation state is detected according to the flowchart shown in FIG. When the molding cycle progresses and shifts to the injection process, the sampling timer starts timing based on the injection start command in the molding machine controller 15, and at the same time, each sensor S1, S2, S3.
The physical quantity detected by is input to the detection controller 4 (steps 51 and 52).

The detection control unit 4 detects the detected change amount dx for each physical quantity.
While monitoring 1, dx2, dx3 (steps 53, 54, 55), each detected change amount dx1 ... is compared with each preset sampling change amount dx1. The value K of each physical quantity when it reaches dx1 ...
1, K2, K3 and time t at that time are detected (step 5).
6, 57, 58). At this time, until the detected change amount dx1 ... In each physical quantity reaches the sampling change amount dx1.
If the sampling time Ts is reached first, the value K1 ... Of each physical quantity at this time and the time t are detected (step 59). Then, the detected value K1 of each physical quantity and the time t are written in the RAM 38 (step 60). At the same time, the detection control unit 4 clears the detected change amount dx1 ... At this time, and again monitors the detected change amount dx1 ... Of each physical quantity (step 61). In this way
Sampling points are sequentially generated, and the values K1 of each physical quantity and the time t at the sampling points are detected to sequentially detect the RAM3.
8 is written, and the detection of one cycle is completed based on the injection end command of the injection process (step 62).

Therefore, if the time t is plotted on the horizontal axis and the physical quantity values K1, K2, K3 are plotted on the vertical axis from the detected data, Vs (K1), Pm (K2), Pi ( It becomes the characteristic curve of K3), and highly accurate change characteristics with respect to physical quantities can be obtained.

Although the embodiments have been described in detail above, the present invention is not limited to such embodiments and can be arbitrarily modified without departing from the scope of the present invention.

〔The invention's effect〕

As described above, the operating state detection method (or detection device) of the injection molding machine according to the present invention sets the sampling time and the predetermined sampling change amount for each physical quantity in advance, detects each physical quantity at the same time, and The detection point of the physical quantity of 1 reaches the sampling change point or the time point of reaching the sampling time, whichever is earlier, whichever is earlier, and the value and time of each physical quantity at the sampling points that occur sequentially are detected simultaneously. Therefore, the following remarkable effects are obtained.

Even when detecting multiple physical quantities at the same time, it is possible to detect with high accuracy with respect to all physical quantities, and since the minimum number of sampling points is sufficient, the capacity of the storage device is reduced and the control system is simplified. It is possible to achieve downsizing and cost reduction of the entire device.

It is possible to confirm the operation of the injection molding machine, confirm the quality of the molded product, search for the optimum molding conditions, etc. easily and in a short time, and perform accurate and highly accurate analysis.

[Brief description of drawings]

1 is a block circuit diagram of an operating state detecting device according to the present invention, FIG. 2 is a schematic configuration diagram of an injection molding machine including the operating state detecting device, and FIG. 3 is a procedure in an operating state detecting method according to the present invention. FIG. 4 is a flowchart showing a part of FIG. In the drawing, 1: Operating state detection device S1, S2 ... S8 (Sn): Sensor 2: Change amount setting device 3: Time setting device 4: Detection control unit

Claims (2)

[Claims] 1. When simultaneously detecting a plurality of physical quantities relating to the operating state of an injection molding machine by sampling, in advance,
Sampling time (interval) and a predetermined sampling change amount for each physical quantity are set, each physical quantity is detected at the same time, and the detection change amount of one of the physical quantities reaches the sampling change amount or reaches the sampling time. The earliest of the time points is the sampling point,
A method for detecting an operating state of an injection molding machine, which is characterized by simultaneously detecting the value of each physical quantity and the time at successively occurring sampling points. 2. A sensor for detecting a plurality of physical quantities relating to the operating state of an injection molding machine, a change amount setter for setting a predetermined sampling change amount for each physical quantity, and a time for setting a predetermined sampling time (interval). A setter and a detection change amount of any physical quantity detected from each sensor reach a sampling change amount or a sampling time at whichever of the sampling time is reached, whichever is earlier. An operation state detection device for an injection molding machine, comprising a detection control unit that simultaneously detects the value of each physical quantity and time.