JP2753060B2 - Color change control method and apparatus for injection molding machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method and an apparatus for controlling color change of an injection molding machine, and in particular, by using surface reflection light of a molten resin and comparing it with an evaluation value set in advance. The present invention relates to a new improvement for determining whether or not the color change has been completed.

[Conventional technology]

There are various color change control methods of this type of injection molding machine that have been used in the past, but the following two types are generally used in-house or the like.

(1) When the color of the molten resin in the cylinder and nozzle of the injection molding machine is changed from resin A having a different color to resin B, the temperatures of the cylinder and nozzle reach a predetermined temperature required for molding resin B. After confirming that the resin B has been manually changed, the proper amount is measured and air purged, and the measurement and air purge are repeated an arbitrary number of times to confirm that the resin B has changed to a predetermined color. By trial and error, or by using an automatic purge circuit,
Either the empirical values of the weighing stroke, the back pressure, the purge speed, and the number of purges are input in advance, and the color change operation is automatically performed until it is confirmed that the color of the resin B has changed to a predetermined color. .

(2) In addition, when performing color change by injecting into a mold, or when managing color variation of a molded product during normal molding, after removing the molded product, judgment by human eyes, or Quantitative judgment was performed using a hue / color difference discriminator.

[Problems to be solved by the invention]

Since the conventional color change control method of the injection molding machine is configured as described above, the following problems exist.

That is, in the case of the conventional method (1), since the molder performs the manual operation, manual operation is required, and it has been difficult to improve the working efficiency and reduce the cost.

Furthermore, in order to perform color discrimination based on the experience and intuition of the molder,
It was qualitative and the error was large, causing problems in product quality.

In the latter case of the conventional method (1), although the automation is possible, the operation may be stopped even if the color change is not always completed due to the setting conditions such as the number of purges.

Further, in the conventional method (2), the color difference is determined after the molded product is taken out, so that the time lag is large and it is not useful for the feedback control to the next shot molding condition. Then, there was a problem that only the treatment was performed, and it was not true online measurement and control.

The present invention has been made to solve the above-described problems, and in particular, it is determined whether color change is completed or not by comparing the reflected light of the surface of the molten resin with a preset evaluation value. It is an object of the present invention to provide a method and an apparatus for controlling color change of an injection molding machine.

[Means for solving the problem]

The color change control method for an injection molding machine according to the present invention is a method for changing the color of a molten resin in a cylinder of an injection molding machine to a color of a new resin to be newly charged into the cylinder, wherein the nozzle or the mold is used. A first step of irradiating the molten resin inside with a light through a transparent window, and a step of taking reflected light from the molten resin as a digital signal through a color identification element and quantifying the reflected light into a color quantitative value by an arithmetic unit. A second step, and a third step of comparing the color quantitative value with the evaluation value of the color of the resin whose color is to be changed. When the color quantitative value matches the evaluation value or falls within the allowable range, the color change is completed. This is a method in which the color change operation is continued in the case of a mismatch or out of the allowable range value.

Another aspect of the present invention is a color change control device for an injection molding machine, which is provided in a nozzle provided in a cylinder, transmits light and irradiates the molten resin with pressure-resistant and heat-resistant transparent windows. Light source, a color identification element that captures the surface reflected light of the molten resin, an A / D converter that converts an analog signal that is the output of the color identification element into a digital signal, and calculates the digital signal into a color quantitative value. A calculation unit provided in the controller, a memory unit provided in the controller for capturing and evaluating the color evaluation value via a setting unit,
A control unit for comparing the evaluation value stored in the memory unit and the color quantitative value calculated by the arithmetic unit to generate a control signal, a display unit for displaying the color quantitative value, and a driving source for a screw in the cylinder And an output controller connected to the controller and connected to the controller.

(Operation)

In the color change control method and apparatus of the injection molding machine according to the present invention, first, for the external light irradiated through the transparent window, the surface reflected light reflected from the molten resin is taken into the color identification element, so that the color After the A / D conversion of the color signal obtained from the discriminating element into a digital signal, the operation unit quantifies it into a color quantitative value.

Prior to this operation, an evaluation value selected by a color quantitative value correspondence table corresponding to the color to be changed is input and stored in the memory, and this evaluation value and the color from the arithmetic unit are stored. The quantitative value is compared with a comparator.

If the color quantitative value matches the evaluation value or falls within a certain allowable range, it is considered that the color change has been completed. Are operated, and the color changing operation is continued.

〔Example〕

Hereinafter, preferred embodiments of a method and an apparatus for controlling color change of an injection molding machine according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a color change control method and apparatus for an injection molding machine according to the present invention.
Is a cylinder having a cylindrical shape, and a heater 2 is provided on the outer periphery of the cylinder 1.

A screw 3 is rotatably provided in a guide path 1a in the cylinder 1, and the screw 3 is provided with a coupling 4
The drive source 5 is connected to the drive source 5 via the.

A nozzle 6 having a discharge hole 6a is attached to the distal end 1b of the cylinder 1. A mounting hole 7 communicating with the discharge hole 6a is formed on a peripheral surface of the nozzle 6, and the nozzle 6 has The transparent window 8 having an outer diameter of 2 to 10 mm made of a light receiving glass such as sapphire glass or quartz glass having excellent pressure resistance, heat resistance, and translucency is formed.

A sensor 11 having a light source 9 and a color identification element 10 as a light receiving element is provided at a position near the outside of the transparent window 8.
Are arranged.

The analog signal 10a from the color identification element 10 is
2. The digital signal 14a is input to the controller 15 via the interface 13 and the A / D converter 14.

The controller 15 includes a calculation unit 16, a control unit 17, a memory unit 18, a setting unit 19, an output unit 20, and a display unit 21, and the digital signal 14a is converted into a color quantitative value 16a by the calculation unit 16.
Is calculated and stored in the memory unit 18, and the setting device
The evaluation value 19a corresponding to the color changing resin set to 19 and the color quantitative value 16a are compared by the control unit 17, and as a result,
In this configuration, the control signal 17a is input to the output unit 20 and the display unit 21.

An output signal 15a of the controller 15 is supplied to the drive source 5 via an output controller 22 and an amplifier 23.

The color change control method and apparatus of the injection molding machine according to the present invention are configured as described above, and the operation thereof will be described below.

First, the molten resin 1A melted by the heating of the heater 2 and the rotation of the screw 3 is stored in front of the screw 3.

In the above-mentioned state, the drive source 5 is operated from the output controller 22 via the amplifier 23 in accordance with the molding condition set value, and the screw 3 is rotated to measure a predetermined amount of the molten resin 1A, or the screw 3 is advanced to measure. The melted resin 1A thus injected is injected into a mold (not shown) or air-purged out of the mold, and this operation is repeated, and another resin A in the cylinder 1 is newly charged into the cylinder 1. The color change is performed on the color resin B.

In the case described above, the evaluation value 19a of the resin B is selected according to the color quantitative value correspondence table shown in the following Table 1, and is previously input to the setting device 19 of the controller 15, and the inside of the air purged nozzle 6 is selected. Light is radiated intermittently from the light source 9 to the molten resin 1A from the light source 9 for a very short time, and the surface reflected light (that is, the wavelength of the color) from the molten resin 1A is taken into the color identification element 10, and the amplifier 1
2. The digital signal 14a is converted into a digital signal 14a via the interface 13 and the A / D converter 14, quantified into a color quantitative value 16a by the arithmetic unit 16, and input to the memory unit 18.

Next, in the control unit 17, the aforementioned color quantitative value 16a and the evaluation value 19a
Are compared or within a certain allowable range, the control unit 17 determines that the color of the resin A has been changed to the color of the resin B, and the output unit 20 sends a signal indicating completion of the color change to the output controller 22. Output controller 20, the output controller 20
At 23, a signal is sent to the effect that the rotation of the screw 3 and the air purge are completed, and the color change is completed.

If the color quantitative value 16a does not match the evaluation value 19a and does not fall within a certain allowable range, the driving source 5 is continuously driven via the output controller 22, and the color changing operation is performed. It is repeated.

Although the case where the above-described transparent window 8 is provided in the nozzle 6 has been described, the same operation and effect can be obtained, for example, in a case where the transparent window 8 is provided in a portion where a molten resin color can be measured in a mold.

〔The invention's effect〕

The color change control method and apparatus of the injection molding machine according to the present invention are configured as described above, and therefore the following effects can be obtained.

That is, since the surface reflection light of the molten resin is extracted by the color identification element and compared with a predetermined evaluation value to determine whether or not the color change has been completed, the color identification error is extremely small. In addition, the time lag from the color difference determination to the next shot forming condition can be minimized, and extremely high efficiency and high precision color changing operation can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a color change control method and apparatus of an injection molding machine according to the present invention. 1 is a cylinder, 1A is a molten resin, 3 is a screw, 5 is a drive source, 6 is a nozzle, 8 is a transparent window, 9 is a light source, 10 is a color identification element, 10a is an analog signal, 14 is an A / D converter, 14a is a digital signal, 15 is a controller, 16 is a calculation unit, 16a is a color quantitative value, 17 is a control unit, 17a is a control signal, 18 is a memory unit, 19
Is a setting device, 19a is an evaluation value, 21 is a display unit, 22 is an output controller, and 23 is an amplifier.

Claims (2)

(57) [Claims] 1. A color change control method for an injection molding machine, wherein a color of a molten resin in a cylinder (1) of the injection molding machine is changed to a new color of a new resin to be injected into the cylinder (1). A first step of irradiating a molten resin (1A) in a nozzle (6) provided in the cylinder (1) or a mold through a transparent window (8) to the molten resin (1A); A second step of taking in the reflected light of the light as a digital signal (14a) via a color discriminating element (10) and quantifying it into a quantitative color value (16a) by a computing unit (16); Evaluation value of the color of the resin to be changed (1
9a) and a third step of comparing the color quantitative value (16
A color change is completed when a) matches the evaluation value (19a) or falls within the allowable range, and the color change operation is continued when the value does not match or falls outside the allowable range. Color change control method for molding machine. 2. A nozzle (6) provided in a cylinder (1).
A transparent window (8) that transmits light and is pressure-resistant and heat-resistant, and a light source (9) that irradiates the molten resin (1A) with light
And a color identification element (10) for receiving the surface reflected light of the molten resin (1A), and an A / D converter for converting an analog signal (10a) output from the color identification element (10) into a digital signal (14a) (14) provided in a controller (15) for calculating the digital signal (14a) into a color quantitative value (16a);
Color evaluation value (19a) provided in the controller (15)
(18) via a setting unit (19) for storing the evaluation value (19a) stored in the memory unit (18) and the color quantitative value calculated by the calculation unit (16) 16a)
Control unit (17) that issues a control signal (17a) by comparing
A display unit (21) for displaying the color quantitative value (16a);
Drive source (5) for screw (3) in cylinder (1)
(23) that outputs command voltage or command current to the
And an output controller (22) connected to the controller (15) and connected to the amplifier (23).