JPH04189524A - Device for judging injection-molded product to be defective in weight - Google Patents

Abstract

PURPOSE:To enable easy and stable judgment, by a method wherein when the maximum injection pressure of measured every shots each are outside of an allowable range of established pressure, a product is decided to be an inferior quality in weight and a judging signal is put out. CONSTITUTION:After beginning of injection molding by a molding machine, injection pressure of a molded product is measured by an injection pressure measuring part based on resin pressure data of every shot to be obtained from a pressure sensor 12 of an injection cylinder 11 and the maximum injection pressure among those pressure is sent to a pressure comparator part 14. An allowable range of the injection pressure which does not become a product of an inferior quality in weight is established. Comparision between the established pressure and maximum pressure is performed and when the maximum injection pressure is outside of the allowable range of the established pressure, it is judged that weight of the molded product is unsuitable and a judging signal is applied to a discharge part 15 of a product of inferior quality. The discharge part 15 of the product of inferior quality discharges the product of inferior quality in weight from an injection molding line. A stabilized judgment can be performed by the above without being affected by a change with time in weight of the molded product, a temperature and moisture.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a weight defective product determination device that determines whether an injection molded product is weight defective by measuring injection pressure.

(Prior Art) Conventionally, a weight defective determination device has been proposed which determines and discharges weight defective injection molded products. This device directly measures the weight of injection molded products, determines whether the products are good or defective based on the measurement results, and discharges only the products with inferior weight.

(Problems to be Solved by the Invention) However, the conventional weight defective product determination device described above is
Judgment is made by directly measuring the weight of the molded product immediately after molding.
Since changes in the weight of the molded product over time and changes in the external environment such as temperature and humidity are not taken into account, there is a problem in that it is not possible to stably determine whether a product is defective in weight.

The present invention focuses on the relationship between injection pressure and molded product weight, and makes weight defective product determination based on the maximum injection pressure, thereby making it possible to easily and stably determine weight defective products. The goal is to provide equipment.

(Means for Solving the Problems) In order to solve the above problems, the weight defective product determination device for injection molded products according to the present invention includes an injection pressure measuring means for measuring the injection pressure for each shot, and an injection pressure measuring means for measuring the injection pressure for each shot. A comparison means compares the maximum injection pressure for each shot measured by the means with a set pressure in which an allowable range of injection pressure is set in advance, and based on the comparison result of this comparison means, the maximum injection pressure is determined to be the set pressure. If the weight is outside the allowable range, the weight of the product is determined to be defective, and a determination unit outputs a determination signal.

(Operation) The injection pressure measuring means equipped with a pressure sensor measures the injection pressure for each shot, and the value of the maximum injection pressure among the measured injection pressures is given to the comparison means. The comparison means is set with an allowable range of injection pressure that does not result in weight defective products, and the comparison means compares this set pressure with the maximum injection pressure given by the injection pressure measurement means, and then determines the maximum injection pressure. When the pressure is within the allowable range of the set pressure, it is determined that the weight of the molded product is appropriate. Further, when the maximum injection pressure is outside the allowable range of the set pressure, it is determined that the weight of the molded product is inappropriate, and a determination signal is output.

In response to this determination signal, for example, a discharge means is operated to discharge the defective products from the injection molding line.

Further, based on this determination signal, for example, a display means displays that the molded product is a weight defective product.

Further, based on this determination signal, for example, an alarm means is activated to issue an alarm that a weight defective product has occurred in the molded product.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the electrical configuration of a weight defective product determination device for injection molded products according to the present invention.

In the figure, an injection cylinder 11 is equipped with a pressure sensor 12 that detects the injection pressure for each shot, and the output of this pressure sensor 12 is led to an injection pressure measuring section 13. Further, the output of the injection pressure measuring section 13 is guided to a pressure comparing section 14, and the output of the pressure comparing section 14 is guided to a defective product discharging section 15. In the above configuration, the pressure comparator 14 is configured by software running on a microcomputer.

The injection pressure measuring section 13 measures the injection pressure of the resin in the injection cylinder 11 detected by the pressure sensor 12, and sends the maximum injection pressure to the pressure comparison section 14.

The pressure comparison unit 14 has a set tolerance range for the injection pressure that does not result in a weight defective product, and the pressure comparison unit 14 compares this set pressure with the maximum injection pressure given from the injection pressure measurement unit 13. conduct. Then, when the maximum injection pressure is within the allowable range of the set pressure, it is determined that the weight of the molded product is appropriate. In addition, when the maximum injection pressure is outside the allowable range of the set pressure, it is determined that the weight of the molded product is inappropriate, and
Outputs a judgment signal.

The defective product discharge section 15 is operated by the determination signal from the pressure comparison section 14, and discharges the weight defective products from the injection molding line.

FIG. 2 is an example of a graph showing the relationship between the maximum injection pressure (kgf/clI) of a molded product and the weight of the molded product (kg).

In a molded product with such a relationship, the weight is 1012
If a good product is from 1,015 g to 1,015 g, the allowable range of maximum injection pressure is 1,730 kgf/cil to 175
Set to 0 kgf/cd. With such a setting, it is possible to discharge approximately 90% of the weight-defective products.

Next, the operation of the weight defective product determination apparatus having the above configuration will be explained with reference to the flowchart shown in FIG.

After injection molding is started by the molding machine, the injection pressure measurement unit 13 measures the injection pressure of the molded product based on the resin pressure data for each shot obtained from the pressure sensor 12 (steps Sl and S2). The injection pressure measurement section 13 sends the maximum injection pressure among the injection pressures detected by the pressure sensor 12 to the pressure comparison section 14 . As mentioned above, the pressure comparison section 14 has an injection pressure tolerance range (17
30 kgf/d to 1750 kgf701), and the pressure comparison unit 14 compares this set pressure with the maximum injection pressure given from the injection pressure measurement unit 13 (step 33). Then, in the judgment in step s3, if the maximum injection pressure is within the allowable range of the set pressure, the weight of the molded product is within the range of 1012g to 1015g according to the graph in Figure 2, so the molding It is determined that the weight of the item is appropriate. In addition, in the judgment in step S3, if the maximum injection pressure is outside the allowable range of the set pressure, the weight of the molded product is between 1012g and 101g.
Since the weight is outside the range of up to 5g, it is determined that the weight of the molded product is inappropriate, and a determination signal is sent to the defective product discharge section 15.
Output to. The defective product discharging unit 15 is operated by the determination signal from the pressure comparison unit 14, and discharges the determined weight defective product from the injection molding line (step S4).

In the above embodiment, a configuration is described in which the defective product discharge section 15 is operated in response to the determination signal from the pressure comparison section 14 to discharge weight defective products from the injection molding line. For example, the signal causes the display means to display that the molded product is defective in weight, or activates the alarm means to issue a warning that the molded product has defective weight. Is possible.

(Effects of the Invention) The weight defective product determination device for injection molded products according to the present invention sets the maximum injection pressure among the injection pressures measured for each shot and the injection pressure within the allowable range that does not result in a weight defective product. The set pressure is compared with the set pressure, and based on the comparison result, it is determined whether the weight of the molded product is defective. This has the effect that it is possible to stably determine the weight of defective products without being affected.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the electrical configuration of the weight defect determination device for injection molded products according to the present invention, and Fig. 2 shows the relationship between the maximum injection pressure (kgf/cd) and the weight of the molded product (kg). A graph showing the relationship, and FIG. 3 is a flowchart for explaining the operation of the device. 11... Injection cylinder 12... Pressure sensor 12 13... Injection pressure measurement section 14... Pressure comparison section 15... Defective product discharge section Patent applicant Sekisui Chemical Co., Ltd. Representative Hiroshi 1) Kaoru

Claims (1)

[Claims] 1) An injection pressure measuring means for measuring the injection pressure for each shot, a maximum injection pressure for each shot measured by the injection pressure measuring means, and an allowable range of the injection pressure being set in advance. a comparison means for comparing the set pressure with the set pressure, and a determination unit that determines that the product is defective in weight and outputs a judgment signal based on the comparison result of the comparison means, when the maximum injection pressure is outside the allowable range of the set pressure. 1. An apparatus for determining defective products by weight for injection molded products, characterized by comprising: means.