JPS60107315A - Measuring method of injection pressure - Google Patents

Abstract

PURPOSE:To improve drastically the quality decision accuracy of a products to be obtained through molding, by a method wherein a pressure detector and a displacement detector of a position of a screw are provided within a cylinder of an injection device at appropriate positions and data to be obtained through those detectors are compared with that of an excellent article by a data processing machine. CONSTITUTION:A pressure detector 14 detecting injection pressure and a displacement detector 15 detecting displacement of a screw 12 in the direction of an arrow F are provided on an injection molding machine injecting a molten material DM to be obtained by heating a material M to be molded by a heating part HT of the injection molding machine in the direction of the arrow F by turning the screw 12 through driving of a motor 11, and detected data from the above pressure detector 14 and the displacement detector 15 are transmitted every one injection cycle to a data processing machine 20 continuously. A wave form of variation properties of the injection pressure of an excellent article is kept stored in a memory in the inside of the foregoing machine 20, and the quality of a product is decided by comparing the stored wave form with properties to be obtained by every product at subsequent mass production molding.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection pressure measuring method for measuring the injection pressure of molten material injected from an injection device into a mold device in an injection molding machine.

[Hatsuyu's technique f lantern-like captor]

Like the inner shaft, the injection molding machine has a screw that rotates and moves inside the cylinder after melting the material to be molded, such as resin, filled in the cylinder of the injection device at a predetermined temperature. The molten material is injected into the mold of the mold device by extruding the molten material while pressing, and it is solidified appropriately to obtain a product having a shape corresponding to the mold. There is.

By the way, when considering such injection molding machines,
There are many processing parameters, and any one of them can be praised, but the injection pressure when the molten abrasive material is injected from the injection device (t) includes all of these parameters. Quality of the above molded product Y iu
It is regarded as important as something that determines the 5M. In the past, if this injection pressure was constantly measured and supervised, it would naturally be possible to determine the quality of the product mentioned above, but in reality, the same injection pressure occurs at an extremely short time + iJ). In addition, even within this single cropping cycle, there are subtle changes due to the structure of the injection device itself and other factors, and it has been considered extremely difficult to accurately measure this.

[Purpose of the invention]

An object of the present invention is to provide an injection pressure measuring method that can easily and accurately measure the injection pressure of the above-mentioned tower melting material, and can also present accurate data for determining the quality of products. do.

[Outline of the invention]

In this invention, a pressure detector is provided at an appropriate position within the cylinder of the injection device to continuously detect the pressure when the molten material is injected, directly or indirectly, and in parallel, the pressure detector is installed in the cylinder of the injection device. The displacement position 11 of the scree is continuously detected by a suitable displacement detector, and the injection pressure of the molten particles corresponding to the detected scree displacement position is set sequentially. This makes it possible to determine the change in the injection pressure of the molten material when it is injected from the injection device with a fairly fine temporal resolution. Therefore, the change waveform of the injection pressure when the molded product is a good product is stored in advance in a storage device, and during subsequent mass production molding, this memorized Kumsugi and measurement extraction for each product are performed. By comparing the same change waveforms, it is possible to immediately and accurately judge the quality of these products.5.

In general, in this type of injection molding, as long as the injection pressure of the bath melt material when injected into the mold device is appropriate, the molding process will continue as long as there is no abnormality in the mold device itself. The product will almost certainly be of good quality.

〔Effect of the invention〕

As described above, according to the injection pressure measuring force method according to the present invention, detailed data regarding the injection pressure can be obtained easily and accurately, and the accuracy of determining the quality of molded products can be significantly improved. . Of course, the use of the measurement data obtained by this method is arbitrary; for example, by simply adding a simple feedback control device to the injection device, it is possible to automatically precisely control the injection pressure based on this measurement data trap, etc. is also possible.

〔Example〕

The figure shows an example of an injection device constructed by applying the injection pressure measuring method according to the present invention.

As shown in the figure, this device melts the molten material DM based on the drive of the motor 11 (the wave forming material M removed from the material receiving portion RV is heated and melted in the heating portion HT of the device). The scree 12 rotates in the direction of pushing out the scree in the direction of arrow F in the figure, the pressure circuit 13 that drives the scree to move in the direction of arrow F & A pressure detector detects the pressure when the material DM is pushed out in the direction of the arrow F by the rotation and movement of the screw 12, that is, when the material DM is injected from the injection device into a mold device (not shown). 14, and a displacement detector 15 for detecting zero displacement of the screw 120 in the direction of arrow F in the figure. The beam making cycle of injecting the molten material DM by the rotation and movement of the molten material DM is repeatedly executed, and the upper i self pressure is detected every work cycle (the actual working cycle required to inject the molten material DM once). The displacement detector 14 operates to continuously transmit detection data obtained from the displacement detector 14 and the displacement detector 15 to the data processing device 20. The data processing device 2o is a device configured by, for example, a computer, and sequentially adjusts the scree position (displacement) as shown in the block in the figure based on the injection pressure detection data and the displacement data of the scree 12 transmitted above. It operates to create a corresponding injection pressure change characteristic waveform. The actual one-shot injection pressure is not always constant within one working cycle of the injection device, but constantly changes, for example, in the manner shown in the figure, depending on the movement position of the screw x12. Such characteristics of the injection pressure can only be obtained by adopting the method of this embodiment in which the same pressure is continuously measured in correspondence with the moving position of the screw 12.

Note that 1. If the rotary encoder 2 is used as the displacement detector 15 and the pulse signal output from the encoder is the displacement data, the displacement of the screw 12 can be detected with an extremely high resolution of about 0.1X unit. The injection pressure variation characteristic waveform produced above can also be made very precise and highly accurate.

Furthermore, the injection pressure change characteristic waveform obtained in this way is set as a standard when the molded product is good as described above (previously stored in the memo in the data processing device 20). ) By comparing the results obtained for each product during subsequent mass production molding, the quality of these products can be easily and accurately determined. When making this determination, the degree of variation in the injection pressure at each position of the scree 12 corresponding to the degree of tolerance of the product is set in advance to a predetermined value of 1. This is the waveform pressure value obtained for each product.
．． 5 so that when the IJ value is exceeded, a signal indicating that the product is defective is appropriately output. Of course, the injection pressure change characteristic waveform ORT% may also be displayed for visual confirmation.

By the way, unlike the above-described embodiment, the pressure sensor 1
4 was installed at the tip of the injection device 6 to directly detect the injection pressure □' of the molten material DM. The injection pressure of M) may be detected indirectly.

[Brief explanation of the drawing]

The figure is a schematic diagram showing an embodiment of the injection pressure measuring method according to the present invention.

Claims (1)

[Claims] A method for measuring the injection pressure of a material to be molded in an injection molding machine, characterized in that the injection pressure of the material to be molded is continuously measured in response to the movement position of the scree. Injection pressure measurement method.