JPH082565B2 - Injection molded product quality determination method and device - Google Patents

Description

The present invention relates to a quality determination method and a quality determination device for an injection molded product.

[Prior art and problems to be solved by the present invention]

In the injection molding, as shown in FIG. 4, the solid resin P in the hopper 3 is fed to the tip of the supply cylinder 1 by the rotation of the screw 2 while being melted by internal heat generation and external heating, a screw by an injection cylinder or an electric motor. 2 is composed of an injection step of controlling the speed of 2 to inject the molten resin P ′ into the mold 4, and a pressure holding step of controlling only the pressure of the resin while the position of the screw 2 remains the same.

FIG. 3 shows the pressure change of the resin with respect to time, and by reading the peak pressure during injection in such pressure change, it may be a substitute characteristic of the quality of the product.

Therefore, in the past, this peak pressure was detected,
If the peak pressure was within the set level range, it was judged as a good product.

However, this peak pressure varies considerably up and down due to the problem of resin compressibility, and there is a problem that it is difficult to judge whether the product is a good product or a defective product, such as a non-defective product even if it is outside the set level range.

The present invention has been made to solve such a problem, and an object thereof is to provide a pass / fail determination method and an apparatus thereof capable of accurately determining a good product and a defective product.

[Means and actions for solving the problem]

It is more effective to judge the product that the position of the peak pressure is selected as the substitute characteristic than the peak pressure of the pressure is regarded as the substitute characteristic of the product. This is clear from the fact that the position reproducibility can be more accurately taken into consideration when considering the process in which the resin enters the mold in the filling process.

The present invention has been made based on such knowledge, and the quality determination method of the present invention is a method for determining the quality of an injection-molded product in injection molding in which a molten resin is injected into a mold by a screw injection. The peak pressure of the molten resin therein is detected, and the screw position at the time when the peak pressure is dropped is detected. If the peak pressure screw position is within the set range, it is determined as a good product.

Another good / bad judgment method is a method of judging the quality of an injection-molded product in injection molding in which a molten resin is injected into a mold by a screw, by detecting the peak pressure of the molten resin during injection and starting the injection. To the point of time when the peak pressure rises, and if the peak pressure time is within the set range, it is determined as a non-defective product.

The quality determination device of the present invention is a method for determining the quality of an injection-molded product in injection molding in which a molten resin is injected into a mold by a screw, a pressure sensor capable of detecting the pressure of the molten resin during injection, and a screw position. It is composed of a position sensor capable of detecting and a signal from these sensors is input to compare the screw position at the peak pressure with the upper and lower set values thereof and to judge that the product is a non-defective product if it is within the set range.

Further, another quality determination device is a method for determining the quality of an injection-molded product in injection molding in which a molten resin is injected into a mold by a screw, and a pressure sensor capable of detecting the pressure of the molten resin during injection, It is composed of an arithmetic processing unit that receives the signal of this pressure sensor, compares the peak pressure time from the start of injection to the point of peak pressure and the upper and lower limit set values, and judges that it is a good product if it is within the set range. There is.

By using the peak pressure screw position or the peak pressure time from the start of injection to the point of peak pressure, the reproducibility is good and the variation is small, so that the good product and the defective product can be accurately determined. In addition, it is possible to accurately determine the quality by a relatively simple device configuration. Furthermore, when the peak pressure time from the start of injection to the point of peak pressure is used, the position sensor can be omitted, and the configuration can be simpler.

〔Example〕

Hereinafter, the present invention will be described based on an illustrated embodiment.

This is an example in which, as shown in FIG. 1, the screw 2 is injected and pressure-controlled by the injection cylinder 5, and a pressure sensor capable of detecting the pressure in the cylinder of the injection cylinder 5, that is, the pressure of the molten resin being injected. A position sensor 7 such as a potentiometer that can detect the screw position by connecting 6
Is connected to piston shaft 5A.

The signals of these sensors 6 and 7 are input to the arithmetic processing unit 10 via the amplifiers 8 and 9 and processed. This arithmetic processing unit
Reference numeral 10 is an A / D converter 11 for converting an analog signal into a digital signal, a high-speed processing unit 12 such as a microprocessor, an IC memory 13 for storing data, an upper / lower limit setting device 14 for a screw position, and a peak pressure indicator. 15, a peak pressure position indicator 16 and the like, and a program written in the high-speed arithmetic processing unit 12 determines the following non-defective products and defective products (see FIG. 2).

 When the program starts, it is judged whether it is injecting.

During injection, the peak pressure data and the screw position data are initialized.

 Judging whether the injection is in progress or completed.

During injection, the pressure data from the pressure sensor 6 is read.

Compare with the previous pressure data stored in the memory 13, and if it is smaller, repeat ~.

If it is larger than the previous pressure data, the pressure data is stored in the memory 13.

Memory for reading screw position data at this time
Store in 13. While the pressure is rising, the loop of ~ is repeated until finally the maximum value of the pressure data, that is, the peak pressure,
The screw position at this time is stored in the memory 13. When this peak pressure is exceeded, the loop of-is repeated.

When the injection is completed, the stored peak pressure data is displayed on the peak pressure indicator 15.

The screw position at this peak pressure is displayed on the position indicator 16.

The screw position at the time of this peak pressure is compared with the upper and lower limit set values from the upper and lower limit setter 14, and as shown in FIG. Alternatively, a normal signal is output to the non-defective / defective product sorter 17. If it is out of the range, an error is displayed and an error signal is output.

In conventional detection using only the peak pressure, the peak pressure value itself fluctuates up and down, but if the screw position has peak pressure, reproducibility is good and there is little fluctuation, so it is possible to accurately judge whether the product is good or defective. You can do well.

Also, the above is determined by the screw position,
The same effect can be obtained even if the time is used. In this case, a timer 18 is provided as shown in FIG. 1, the time from the start of injection to the point of peak pressure is detected, and if this peak pressure time is within the set range, it is judged as a good product.

The pressure sensor 6 is not limited to the injection cylinder and may be connected to the mold 4 to directly detect the pressure.

〔The invention's effect〕

Since the present invention has the above configuration, the following effects can be obtained.

(I) The screw position at the time of peak pressure is detected, and if the peak pressure screw position is within the set range, it is determined as a good product, so that a good product and a defective product can be accurately determined.

(Ii) Accurate determination can be performed with a relatively simple configuration.

(Iii) If a timer is used, the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an apparatus according to the present invention, FIG. 2 is a similar flowchart, FIG. 3 is a graph showing pressure change, and FIG. 4 is a schematic diagram showing an injection molding machine. 1 ... Supply cylinder, 2 ... Screw, 3 ... Hopper, 4 ... Mold, 5 ... Injection cylinder, 6 ... Pressure sensor, 7 ... Position sensor, 8, 9 ... Amplifier, 10 ... Processor 11 …… A / D converter 12 …… High-speed calculation unit, 13 …… Memory 14 …… High and low limit setting device 15 …… Peak pressure display 16 …… Position display, 17 …… Sorting machine 18 …… Timer.

Claims (4)

[Claims] 1. A method for determining the quality of an injection-molded article in injection molding, in which a molten resin is injected into a mold by a screw, the peak pressure of the molten resin being injected is detected, and the peak pressure at the time of this peak pressure is reached. Detect screw position,
An injection molded product quality determination method, characterized in that if the peak pressure screw position is within a set range, it is determined as a good product. 2. A method for determining the quality of an injection-molded article in injection molding, wherein a molten resin is injected into a mold by a screw, the peak pressure of the molten resin being injected is detected, and the peak pressure Measure the time until the standing time,
If the peak pressure time is within the set range, it is judged as a non-defective product. 3. An apparatus for determining the quality of an injection-molded product in injection molding, wherein a molten resin is injected into a mold by a screw, and a pressure sensor capable of detecting the pressure of the molten resin during injection.
It is equipped with a position sensor that can detect the screw position and an arithmetic processing unit that receives signals from these sensors, compares the screw position at peak pressure with its upper and lower set values, and determines that the product is a good product if it is within the set range. A device for determining the quality of an injection-molded product, which is characterized in that 4. An apparatus for determining the quality of an injection-molded product in injection molding, wherein a molten resin is injected into a mold by a screw, and a pressure sensor capable of detecting the pressure of the molten resin during injection.
The signal of this pressure sensor is input, the peak pressure time from the start of injection to the point of peak pressure is compared with the upper and lower limit set values, and if it is within the set range, it is equipped with an arithmetic processing unit. A device for determining the quality of an injection-molded product, which is characterized in that