JP2007021797A - Mold monitoring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold monitoring device which can properly adjust the positions of a monitoring camera and an illuminant while watching a display part and can exactly monitor the state of the surface of a movable mold although visible light is used. <P>SOLUTION: In the mold monitoring device comprising the illuminant projecting light on the surface of the movable mold of a molding machine having a fixed mold and the movable mold which are in the relation of male and female, the monitoring camera monitoring the state of the surface of the movable mold based on reflected light by the surface, and a device main body having the display part displaying an image obtained by the monitoring camera, the illuminant radiating light of a specified wavelength range is used. The effective wavelength region of the light does not exist in a visible region below 600 nm in wavelength but exists in a visible region at least 600 nm in wavelength and in an infrared region. The monitoring camera is provided with a wavelength selective filter having cut-on wavelengths in a wavelength range of 600-650 nm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mold monitoring apparatus that monitors a state of a mold surface of a movable mold in, for example, an injection molding machine using a monitoring camera.

For example, as shown in FIG. 7, in an injection molding machine for manufacturing a resin molded product, which includes a fixed mold 51 and a movable mold 53 that are in a male-female relationship, the fixed mold 51 and the movable mold A molded product is manufactured by filling a molten resin into a space formed by closely contacting the mold 53 and solidifying by cooling. Thereafter, in a state where the movable mold 53 is retracted and separated from the fixed mold 51, the molded product attached and held on the movable mold 53 is taken out from the movable mold 53 by a not-shown protruding mechanism, It is transported to the storage space. The fixed mold 51 and the movable mold 53 are fixed to the fixed platen 50 and the movable platen 52, respectively.
In the injection molding machine having such a configuration, for example, if both molds are closed while the molded product remains in the movable mold 53, the molds themselves are damaged. Therefore, it is necessary to monitor the state of the mold surface 53A of the movable mold 53, so that the state of the mold surface 53A of the movable mold 53 is monitored. Various types of mold monitoring devices have been proposed (see, for example, Patent Document 1).

As such a mold monitoring apparatus, as shown in FIG. 7, the state of the mold surface 53A of the movable mold 53 is photographed by a monitoring camera 63 fixed to a fixed platen 50 provided with a fixed mold 51. In this case, a configuration in which monitoring is performed sequentially is known. In the figure, reference numeral 62 denotes an apparatus main body provided with a display unit 61 for displaying an image obtained by the monitoring camera 63, and reference numeral 64 denotes camera holding means for holding the monitoring camera 63.
The method for monitoring the state of the mold surface 53A of the movable mold 53 will be described in detail. The state of the mold surface 53A of the movable mold 53 after a series of molding operations is taken by the monitoring camera 63 is obtained. The brightness level of the obtained image is compared with the reference image stored in the apparatus main body 62 in advance, that is, the reference brightness level of the image when the resin molded product is not attached to the mold surface 53A of the movable mold 53. Thus, the presence or absence of a molded product in the mold is detected.

  However, in the mold monitoring apparatus 60 of such a monitoring method, for example, when the luminance of visible light emitted from the illumination provided in the factory where the mold monitoring apparatus 60 is disposed has changed for some reason. Due to the influence of ambient light, for example, there is a problem of causing a malfunction such as determining that there is a molded product even though there is no molded product in the mold.

For such a problem, for example, infrared rays emitted from a number of light emitting diodes are projected onto the mold surface of the movable mold, and the infrared rays reflected by the mold surface of the movable mold are blocked from visible light. There has been proposed a mold monitoring apparatus configured to enter an image sensor through a filter having an image and thereby image a mold surface of a movable mold (see Patent Document 2).
According to the mold monitoring apparatus having such a configuration, it is possible to eliminate in principle the influence of visible light due to external illumination or the like around the injection molding machine, thereby reliably preventing the malfunction described above. It is described that it is possible.
Japanese Patent No. 3397355 JP 2003-305748 A

However, the technique disclosed in Patent Document 2 has the following problems. That is, when performing injection molding of resin or the like, the operator adjusts the position so that the light source that illuminates the monitoring camera and the mold surface of the movable mold is placed at an optimal position with respect to the mold surface of the movable mold. It is necessary to do. Such position adjustment work is normally performed while visually recognizing an image displayed on the display unit.
However, in the technique, since visible light is blocked by a filter, it is difficult for an operator to visually recognize an image displayed on the display unit. Therefore, the position adjustment of the surveillance camera, for example, a photographing range (field of view), Complicated work is required to adjust the shooting angle and aim, and the predetermined position adjustment work cannot be performed appropriately.
Further, the same problem occurs when performing the light source position adjustment operation.

  The present invention has been made based on the circumstances as described above, and the position adjustment of the monitoring camera and the light source can be appropriately performed while visually recognizing the image displayed on the display unit. An object of the present invention is to provide a mold monitoring apparatus that can accurately and accurately monitor the state of a mold surface of a movable mold while being used.

The mold monitoring apparatus of the present invention includes a light source that projects light toward a mold surface of the movable mold, and a movable mold of a molding machine that includes a fixed mold and a movable mold that are in a male-female relationship. Based on the light reflected by the mold surface, a monitoring camera that monitors the state of the mold surface of the movable mold, and an apparatus body having a display unit that displays an image obtained by the monitoring camera,
As the light source, one that emits visible light in at least a part of the wavelength range of 600 to 770 nm and infrared light having a wavelength of 770 nm or more is used.
The present invention is characterized in that it has no effective wavelength region in the visible region having a wavelength of less than 600 nm, and has effective wavelength regions in the visible region and infrared region having a wavelength of 600 nm or more.
Here, the “effective wavelength range” refers to a wavelength range in which the mold monitoring apparatus exhibits sensitivity.

In the mold monitoring apparatus of the present invention, the monitoring camera may be configured to include a wavelength selection filter having a cut-on wavelength in the wavelength range of 600 to 650 nm.
The “cut-on wavelength” refers to a wavelength at which the transmittance becomes 5% when the transmittance increases from the short wavelength blocking region and shifts to the peak transmittance.

According to the mold monitoring apparatus of the present invention, by having an effective wavelength range in the visible range and the infrared range of the specific wavelength range, the mold of the movable mold is based on the visible range and the infrared range of the specific wavelength range. Since the image data of the surface is acquired, the position adjustment work of the light source and the monitoring camera with respect to the mold surface of the movable mold can be performed while viewing the image displayed on the display unit. Furthermore, since the visible wavelength range in the effective wavelength range is limited to an appropriate size, it is not affected by disturbance light while using visible light. The condition of the mold surface of the movable mold can be accurately monitored with high reliability.
Specifically, since the surveillance camera is provided with a wavelength selection filter whose cut-on wavelength is within a specific wavelength range, an effective wavelength range is set in a visible wavelength range and an infrared wavelength range greater than the cut-on wavelength. The state which has is achieved and the said effect can be acquired reliably.

FIG. 1 is an explanatory perspective view showing an outline of a configuration of a main part in an example of an injection molding machine to which a mold monitoring apparatus of the present invention is attached in a state where both molds are opened.
The injection molding machine includes a fixed mold 11 fixed to a fixed platen 10, and a movable platen 15 connected to the fixed platen 10 and a guide rail (not shown) so as to be movable forward and backward. And a movable mold 16 fixed to. The fixed mold 11 and the movable mold 16 are in a male-female relationship.

  The mold monitoring apparatus includes a light source 20 that projects light toward a mold surface 16A of a movable mold 16 that is a monitoring surface provided on the upper surface of the fixed platen 10, and a movable that is provided on the upper surface of the fixed platen 10. A monitoring camera 30 for monitoring the state of the mold surface 16A of the mold 16, a camera holding means 25 for holding the monitoring camera 30, and a movable mold in which appropriate image processing has been performed on image data captured by the monitoring camera 30. The apparatus main body 22 provided with the display part 23 which displays the image of the mold surface 16A of the type | mold 16 and the connection cable 24 which electrically connects the monitoring camera 30 and the apparatus main body 22 are provided.

As the light source 20, a light source that emits visible light in at least a part of the wavelength range of 600 nm to 770 nm and infrared light in the wavelength range of 770 nm or more is used. In this embodiment, for example, as shown in FIG. An illuminating device including an incandescent bulb having such light emission characteristics is used. In the present invention, “visible light” means light in the wavelength range of 380 nm to 770 nm.
In the lighting device used in this embodiment, for example, a light emitting section provided with an incandescent bulb is held by a deformable holding means 21, whereby the projection angle of light emitted from the incandescent bulb can be freely adjusted. Has been.

  As shown in FIG. 3, the monitoring camera 30 includes a cylindrical casing 31, an imaging unit 35 fitted in the opening on the movable mold side in the casing 31, and an image data signal obtained by the imaging unit 35. And a control circuit 32 having a function of transmitting the image to the apparatus main body 22, and the photographing angle can be freely adjusted with the light incident surface inclined so as to be directed to the mold surface 16 A of the movable mold 16. It is held by the camera holding means 25.

  The imaging unit 35 includes a wavelength selection filter 36 having specific optical characteristics, a condensing lens 37 for condensing the light transmitted through the wavelength selection filter 36, and images the collected light to form image data. Are arranged in this order with respect to the incident direction of the reflected light reflected by the mold surface 16A of the movable mold 16.

The wavelength selection filter 36 is formed by forming a dielectric multilayer film on the surface of a base material, and the cut-on wavelength is 600 to 650 nm so that light having a wavelength of 600 nm or less is blocked by the composition of the dielectric multilayer film. Is set within the wavelength range.
In this embodiment, as the wavelength selection filter 36, for example, a thickness obtained by laminating two layers of a beryllium oxide layer having a thickness of 0.2 μm and a magnesium fluoride layer having a thickness of 0.1 μm in this order. A dielectric multilayer film having a thickness of 0.3 μm is formed on the surface of a base material made of glass having a thickness of 3 mm, and has a characteristic as shown in FIG.

  The reason why the cut-on wavelength is defined in the above numerical range is as follows. That is, when the cut-on wavelength is set to less than 600 nm, there is no problem in performing the position adjustment operation of the monitoring camera 30 and the light source 20 described later, but a relatively wide wavelength range including short-wavelength visible light. Visible light passes through the wavelength selection filter 36, the amount of transmitted visible light increases, and when checking the presence or absence of a molded product remaining in the mold, it is affected by disturbance light such as factory lighting. It becomes easy. On the other hand, when the cut-on wavelength is set to 650 nm or more, there is no problem in confirming the presence or absence of a molded product remaining in the mold, but the wavelength range of visible light transmitted through the wavelength selection filter 36 is narrow. This is because the transmitted light amount of visible light is reduced and the position adjustment work of the monitoring camera 30 and the light source 20 is hindered.

  As the sensor element 38, one having sensitivity in a wavelength range of 1000 nm or less is used. In this embodiment, for example, a spectral sensitivity characteristic as shown in FIG. 5, that is, one having a peak sensitivity at a wavelength of 600 nm is used. Yes.

Hereinafter, a method for monitoring the state of the mold surface 16A of the movable mold 16 by the mold monitoring apparatus will be described.
First, the position adjustment operation of the light source 20 and the monitoring camera 30 is performed in a state where the movable mold 16 is opened so as to be positioned at a predetermined monitoring position. Specifically, for example, the projection angle of the light source 20 is adjusted so that the entire mold surface 16 </ b> A of the movable mold 16 is irradiated, and the surveillance camera 30 is displayed on the display unit 23 of the apparatus main body 22. While visually recognizing the image of the mold surface 16A of the mold 16, the monitoring range (field of view), imaging angle, aiming, and the like are adjusted so that visible light reflected by the mold surface 16A of the movable mold 16 is effectively detected. .
Image data used when the position of the monitoring camera 30 is adjusted is acquired as follows. That is, when the light source 20 is turned on and light emitted from the light source 20 is projected onto the mold surface 16A of the movable mold 16 positioned at a predetermined monitoring position, visible light and infrared light reflected by the mold surface 16A are reflected. Is incident on the sensor element 38 through the wavelength selection filter 36 and the condenser lens 37 in the monitoring camera 30, and is imaged by the sensor element 38 to obtain an image data signal. The image data signal is transmitted to the apparatus main body 22 by the function of the control circuit 32, subjected to appropriate image processing by the apparatus main body 22, and then displayed on the display unit 23 of the apparatus main body 22.

Then, monitoring of the state of the mold surface 16A of the movable mold 16 in the actual molding process, that is, confirmation of the presence or absence of the molded product remaining in the mold is performed in advance with at least the mold surface in a state where the molded product is not adhered and held. The 16A image is acquired as reference image data, recorded (registered) in the apparatus main body 22, and moved after a series of molding processes including the above-described filling of molten resin, cooling and solidification, and conveyance of a molded product are performed. This is done by comparing the image data obtained by capturing the state of the mold surface 16A of the mold 16 with the monitoring camera 30 and the reference image data.
Specifically, when the brightness level of the image data after the molding process is matched with the reference brightness level of the reference image data, it is determined that no molded product remains in the mold, and the next. If the molding process is performed and the reference brightness level does not match the reference image data, it is determined that the molded product remains in the mold, and the controller for controlling the operation of the movable platen 15 is used. Then, a control signal is transmitted from the apparatus main body 22, and the molding operation is stopped.

Thus, according to the mold monitoring apparatus having the above-described configuration, the monitoring camera 30 includes the specific wavelength selection filter 36 whose cut-on wavelength is in the wavelength range of 600 to 650 nm and has a wavelength range of 1000 nm or less. And a sensor element 38 having a peak sensitivity at a wavelength of 600 nm. Thus, there is no effective wavelength region in the visible region with a wavelength of less than 600 nm, and in the visible region and infrared region with a wavelength of 600 nm or more. Since it is configured to have an effective wavelength region, image data of the mold surface 16A of the movable mold 16 is acquired based on visible and infrared light having a cut-on wavelength or more, so the operator can monitor The position adjustment work of the camera 30 and the light source 20 can be performed while visually recognizing the display unit 23 of the apparatus main body 22. Therefore, the predetermined position adjustment work can be appropriately performed. It can be carried out and easily.
Moreover, since the wavelength range of visible light having sensitivity is narrowed to a wavelength range close to the infrared region that is equal to or higher than the cut-on wavelength by the function of the wavelength selection filter 36, visible light can be clearly seen from the experimental results shown in FIG. In other words, while the monitoring camera 30 is sensitive to visible light, it is not substantially affected by disturbance light, and the state of the mold surface 16A of the movable mold 16 is monitored. The presence or absence of a molded product remaining in the mold can be confirmed accurately with high reliability.

An example of an experiment conducted to confirm the monitoring accuracy of the mold monitoring apparatus in the above embodiment is shown as an injection molding machine using a wavelength selection filter 36 in the monitoring camera 30 having a cut-on wavelength set to 600 nm. The operating conditions of the above are set so that 200 molding operations are performed per hour, the mold surface 16A of the movable mold 16 is monitored, and the number of times of erroneous recognition occurring during 24 hours is examined. As shown by the solid line, by providing the specific wavelength selection filter 36, even when the setting sensitivity of the surveillance camera 30 is set high, the frequency of occurrence of erroneous recognition can be suppressed low and high. It was confirmed that it can be monitored with accuracy. Here, the “number of occurrences of erroneous recognition” is determined by an operator's judgment on the state of the mold surface 16A of the movable mold 16 by visually recognizing an image displayed on the display unit 23, and by the apparatus main body 22. The case where the judgment made is different is counted as the occurrence of misrecognition.
On the other hand, when a similar experiment was performed using a comparative mold monitoring apparatus having the same configuration as that of this example except that the wavelength selection filter was not provided, as shown by a broken line in FIG. Even when the set sensitivity of the surveillance camera to be set is low, it has been confirmed that erroneous recognition occurs and the frequency of occurrence of erroneous recognition increases rapidly as the set sensitivity is set higher. This is because, as is apparent from the sensitivity characteristics of the sensor element 38 shown in FIG. 5, the sensor element has sensitivity in the wavelength range covering almost the entire visible range, and is therefore easily affected by ambient light. it is conceivable that.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, in the mold monitoring apparatus of the present invention, the light source only needs to emit visible light in at least a part of the wavelength range of 600 nm to 770 nm and infrared light in the wavelength range of 770 nm or more. Not only a light bulb but also a discharge lamp or a light emitting diode can be used. Moreover, the installation position of the light source is not limited to the upper surface of the fixed platen, and can be attached to any other surface of the fixed platen or the movable platen.
In the mold monitoring apparatus of the present invention, the field of view of the monitoring camera does not have to be the entire area of the mold surface of the movable mold, and it is only necessary to cover the area where the molded product is to be adhered and held.

  Furthermore, in the monitoring method implemented in the mold monitoring apparatus of the present invention, for example, as reference image data, image data in a state in which a molded product (confirmed as a non-defective product) is adhered and held is recorded (registered). The image data of the mold surface in a state where the molded product is manufactured and the mold is opened, that is, before the molded product is protruded from the mold, is compared with the reference image data. Thus, it may be confirmed whether or not the molding is normally performed.

It is an explanatory perspective view showing roughly the composition of the important section in an example of the injection molding machine with which the metallic mold monitoring device of the present invention was attached. It is a figure which shows the emission spectrum curve of the illuminating device used in a present Example. It is explanatory drawing which shows the example of 1 structure of the surveillance camera in a present Example. It is a figure which shows the characteristic in case an incident angle is 0 degrees of the wavelength selection filter in a present Example. It is a figure which shows the spectral sensitivity characteristic of the sensor element in a present Example. It is a figure which shows the result of the experiment conducted in order to confirm the monitoring precision of the metal mold | die monitoring apparatus in a present Example. It is explanatory drawing which shows schematically the structure of the principal part in an example of the conventional injection molding machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fixed platen 11 Fixed mold 15 Movable platen 16 Movable mold 16A Mold surface 20 Light source 21 Holding means 22 Apparatus main body 23 Display part 24 Connection cable 25 Camera holding means 30 Monitoring camera 31 Casing 32 Control circuit 35 Imaging part 36 Wavelength selection filter 37 condensing lens 38 sensor element 50 fixed platen 51 fixed mold 52 movable platen 53 movable mold 53A mold surface 60 mold monitoring device 61 display unit 62 device body 63 monitoring camera 64 camera holding means

Claims (2)

A light source that projects light toward a mold surface of the movable mold and a light reflected by the mold surface of the movable mold of a molding machine having a fixed mold and a movable mold that are in a male-female relationship. Based on the mold monitoring apparatus comprising a monitoring camera for monitoring the state of the mold surface of the movable mold, and an apparatus main body having a display unit for displaying an image obtained by the monitoring camera.
As the light source, one that emits visible light in at least a part of the wavelength range of 600 to 770 nm and infrared light having a wavelength of 770 nm or more is used.
A mold monitoring apparatus characterized by having no effective wavelength range in the visible range of wavelengths less than 600 nm, and having an effective wavelength range in the visible range and infrared range of wavelengths of 600 nm or more.   The mold monitoring apparatus according to claim 1, wherein the monitoring camera includes a wavelength selection filter having a cut-on wavelength in a wavelength range of 600 to 650 nm.