JP2004191135A - Method for inspecting molding defective hole of cast molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for inspecting the molding defective hole of a cast molded product, wherein the blockade in a complicated flow passage is inspected. <P>SOLUTION: One or more floodlight projectors 10 are provided to the outside communication openings of one or more flow passages formed in the cast molded product and the pulse lights emitted from one or more floodlight projectors 10 are detected by the omnidirectional light detecting surface 21 of one light guide member 20 provided to the separate outside communication openings of the flow passages corresponding to the respective flow passages formed in the cast molded product provided with one or more floodlight projectors 10 and the passed lights are guided to the photodetector 30 provided to the end part of the light guide member 20. The detection output of the passed lights detected by the photodetector 30 is compared with a threshold value to measure the blockade degree of the flow passages to judge the quality of the flow passages. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for inspecting a molded article for defective molding holes for inspecting whether a flow path formed in the molded article is clogged or narrowed.
[0002]
[Prior art]
2. Description of the Related Art A flow passage (water jacket) through which cooling water passes is formed in a complicated manner inside a cast molded product such as a cylinder block or a cylinder head of an automobile. This flow path is obtained by disposing a core in a mold, but when the core is broken or collapsed due to heat or molten metal flow during casting and the flow path is clogged or narrowed, cooling water is discharged. Since there is a possibility that the flow stops or the flow deteriorates to cause poor cooling and cause engine failure such as overheating, all the flow paths must be inspected after casting and molding. In addition, a complicated flow path which is curved or has a step in the middle like a flow path formed so as to surround a cylinder or a plug hole is liable to be clogged or narrowed due to poor molding.
[0003]
For this reason, it is necessary to determine the quality of the flow path that is complicated and meandering by hand through a wire or the like, or to judge the quality by irradiating light from the opening at the start end of the flow path and looking at the reflected light passing through it. However, it is extremely difficult to pass the wire through the complicated and meandering channel, and since the inner surface of the channel is roughened by molding sand, almost no light is reflected in the meandering channel. The inspection light was attenuated and did not reach the terminal aperture. Even if the light reaches the terminal opening, the attenuation is so severe that it has been extremely difficult to detect the degree of blockage.
[0004]
Therefore, there is a device that supplies air into the flow path from the start end opening and detects the air pressure and the air flow rate at the end opening with a sensor (for example, see Patent Documents 1 and 2). However, it is impossible to supply air pressure only to the flow path to be inspected, and since the flow path is not so long, a large pressure difference cannot be obtained between both ends, so that an enormous amount of air is required. Moreover, since the air pressure and the air flow rate also leak out of the other flow paths, the air flow is attenuated to 1/1000 or less at the branch point and is not at a level at which the quality can be judged. Further, there is an apparatus that performs an inspection based on a wind speed (see Patent Document 3). In addition, there is an apparatus that performs inspection using ultrasonic waves (see Patent Document 4).
[0005]
[Patent Document 1] JP-A-3-105203 [Patent Document 2] JP-A-6-281548 [Patent Document 3] JP-A-2001-116663 [Patent Document 4] JP-A-2000-338090 ]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a method for inspecting a defective molding hole in a cast molded product, which can inspect the degree of blockage in a complicated flow path.
[0007]
[Means for Solving the Problems]
In order to achieve the above-described object, the present invention provides a method for transmitting pulse light emitted from one or more light emitters provided in an external communication opening of one or more flow paths formed inside a cast molded product to another external light source. The light is received by the omnidirectional light receiving surface of one light guide member provided in the communication opening, and then guided to the light receiver provided at the end of the light guide member, and the light output detected by the light receiver is compared with a threshold value. The invention of claim 1 provides a method for inspecting defective molding holes in a cast molded product, which performs pass / fail judgment, and the method for inspecting defective molding holes in a cast molded product in which the light guide member is transparent glass or transparent resin. According to a second aspect of the present invention, there is provided a method for inspecting a defective molding hole of a cast product in which the light guide member is a light guide fiber bundle, wherein the omnidirectional light receiving surface is provided in the first to third aspects. Unsatisfactory molding of a cast product consisting of an approximately conical ground glass part According to a fourth aspect of the present invention, there is provided the hole inspection method according to the first, second, or fourth aspect, wherein a method of inspecting a defective molding hole of a cast molded product in which the base end diameter of the light guide member is smaller than the diameter of the shaft portion. In the invention according to claims 1 to 5, the method for inspecting a defective molding hole of a cast molded product in which the light emitter is a light emitting diode is the invention according to claim 6, and in the invention according to claims 1 to 6, the plurality of light emitters are pulsed. The invention of claim 7 is a method for inspecting a defective molding hole of a cast molded product which emits pulsed light at a timing not overlapping with the distribution circuit.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, a preferred embodiment of the present invention for inspecting the flow path of the cylinder head will be described in detail with reference to the drawings.
The measuring apparatus 1 of the present invention includes a plurality of light emitters 10 for emitting pulse light, one light guide member 20 having an omnidirectional light receiving surface 21 for receiving pulse light passing through the flow path R, and a light guide member 20. , One light receiver 30 for detecting the transmitted light guided to the base end, and the plurality of light projectors 10 and one light guide member 20 are provided separately for the respective flow paths R formed inside the casting. It is provided in the external communication opening.
[0009]
As shown in FIG. 3, the light projector 10 includes a pulse oscillator 11, a pulse distribution circuit 12, an amplifier 13, and a light emitting diode 14. By applying a pulse signal to the light emitting diode 14 by the pulse distribution circuit 12, pulse light with an increased instantaneous peak output can be emitted, so that high-luminance light emission is possible even with a small power consumption and a small output light emitting diode 14. Therefore, it is possible to withstand the attenuation of the pulse light caused by passing through the flow path R formed by the rough surface of the cast molded product, and because it is small, the small external communication opening of the flow path R of the cast molded product is small. Can be arranged.
[0010]
Further, when the measured distance of the flow path R is long and the attenuation of the pulse light is large and the light output is insufficient, the output shortage can be compensated for by arranging a plurality of light emitting diodes 14 to emit light. Further, the light emitting color of the light emitting diode 14 may be colored light. However, if infrared light is used, the light is hardly affected by disturbance light. Although the light emitting diode 14 has directivity as shown in FIG. 6, when the directivity varies in characteristics, the detection accuracy is improved by using a light emitting diode having a light directivity rather than a sharp directivity. Further, the shorter the duration of the pulse of the light emitting diode 14, the higher the peak output becomes. However, if the projector 10 generates an extremely short pulse, the circuit design becomes difficult and expensive, so It is preferable to set the time. Further, the light emitting diode 14 is housed in a protective tube having an opening on the side of the emission direction of the pulse light so as to prevent the light emitting diode 14 from being inadvertently damaged during the inspection.
[0011]
The pulse oscillator 11 generates a rectangular pulse having a period of 1 to 100 KHz, and the pulse width is set to a fraction of the period. The pulse distribution circuit 12 distributes pulses sequentially at a timing that does not overlap the light emitting diodes 14 of the four projectors 10.
[0012]
As shown in FIG. 3, the light receiver 30 includes a light receiving element 31, an amplifier 32, an analog switch 33, a comparator 34, and a display 35. The light receiver 30 is a base end of the light guide member 20. It is provided in. The analog switch 33 distributes the light output received by the light receiver 30 at the timing of the light projector 10. As shown in FIG. 7, the comparator 34 determines the quality of the flow path R based on whether the detected light receiving output exceeds or does not exceed a threshold value. The display 35 is for displaying a closed flow path R and a flow path R below a threshold value with a lamp. Further, the same number of the amplifiers 32, the analog switches 33, the comparators 34 and the indicators 35 as the light emitting diodes 14 of the light projector 10 are provided, and one-to-one correspondence is provided. Although the number of the light receiving elements 31 is one, the amplifier 13 of the light projector 10 and the analog switch 33 of the light receiver 30 are synchronously coupled, so that one-to-one correspondence is performed.
[0013]
The light guide member 20 is made of a circular or square transparent glass, a transparent plastic, a light guide fiber bundle, or the like having a substantially conical polished glass-like portion at the tip serving as an omnidirectional light receiving surface 21. The outer peripheral surfaces of the transparent glass, the transparent plastic, and the light-guiding fiber serve as reflection surfaces so that the received pulsed light is not attenuated by leakage to the outside during light guiding. Further, by forming the omnidirectional light receiving surface 21 as a polished glass portion, light is easily absorbed without being reflected, so that even a small amount of light can be reliably received. Further, the tip is formed as an omnidirectional light receiving surface 21 having a substantially conical shape, so that pulse light incident from all directions of the light guide member 20 can be reliably received. As shown in FIGS. 4A and 4B, the light guide member 20 made of transparent glass or transparent plastic has a base end diameter smaller than a shaft diameter to concentrate incident light and reduce luminance. Since it can be increased, detection by the light receiver 30 can be ensured. In addition, since the base end diameter can be reduced, the light receiver 30 having a light receiving surface with a small area can be used, and the cost can be reduced.
[0014]
Further, the relationship between the aperture ratio obtained using the experimental apparatus shown in FIG. 9 and the output of the received light of the passing light was such that the degree of blockage could be clearly determined as shown in the graph of FIG. In this experiment, the light projector 10 was arranged at the beginning of the square pipe, and the light receiver 30 was arranged at the end of the square pipe. When the shielding plate provided in the middle of the square pipe was protruded and retracted, the light was received by the light receiver 30. Of the received light output. In the experiment, the degree of blockage can be clearly discriminated, but in the case of an actual cast molded product, as shown in FIG. 8, there is a slight variation in the channel size between the products. By obtaining the average value in advance, the detection accuracy can be improved.
[0015]
In this configuration, the cylinder head H is placed on the inspection table in a horizontal direction, and the four light projectors 10 and one light guide member 20 of the measuring device 1 are mounted on the cylinder head H as shown in FIG. Are positioned and arranged at the respective external communication openings of the flow path R at a predetermined distance to be inspected. Next, the pulse output oscillated from the pulse oscillator 11 is sequentially input to each amplifier 13 for amplifying the light emitting diode 14 of each projector 10 so that the emission timing does not overlap by the pulse distributor 12. Thus, the four light emitting diodes 14 emit pulse light at different timings.
[0016]
The pulsed light emitted from the projector 10 in this way travels through the flow path R as shown in FIG. The pulse light travels while repeating reflection when the flow path R is non-linear, and travels straight when the flow path R is linear. The passing light reaches the omnidirectional light receiving surface 21 of the conical ground glass portion of the light guide member 20. Since the omnidirectional light-receiving surface 21 of the ground glass portion has a conical shape, it also receives a small amount of passing light coming from almost all directions. The transmitted light is received. Then, the light is guided to the base end of the light guide member 20 which is received by the ground glass portion of the omnidirectional light receiving surface 21. Next, the transmitted light is detected by the light receiver 30 provided at the base end.
[0017]
The pulse light from the other light emitting diodes 14 is sequentially emitted to the flow path R at a timing at which they do not overlap each other, and is received by the omnidirectional light receiving surface 21 of the light guide member 20 unless the flow path R is closed. By 30, the passing light is detected. The pulse light from each light emitter 10 is detected by one light receiver 30. However, since the analog switch 33 of the light receiver 30 is synchronously coupled with the amplifier 13 of the light emitter 10, The passing light received by the omnidirectional light receiving surface 21 is detected in a one-to-one correspondence without being mixed as a light receiving output for each flow path R.
[0018]
Since the light reception output detected by the light receiver 30 changes according to the degree of obstruction of the flow path R due to the narrowing or occlusion of the flow path R, the light reception output of an allowable level set based on the accumulated data. Is set as a threshold value, and when the set threshold value is exceeded, it is determined that there is no blockage or stenosis exceeding an allowable level in the flow path R, and the flow path R is determined to be a non-defective product having no abnormality.
[0019]
In the preferred embodiment, the light guide member 20 is made of hard transparent glass or transparent plastic. However, if a flexible light guide fiber is used, the light receiver 30 can be arranged at a position distant from the test object. Since it is possible to prevent the light receiver 30 from being damaged or soiled, long-term durability can be achieved. Moreover, since the light guide member 20 made of a light guide fiber is more resistant to impact than a hard one, it is not damaged and can be used for a long time, and the running cost can be reduced. Further, in the preferred embodiment, the light projector 10 using the light emitting diode 14 is used. However, it is needless to say that the light projector 10 using a laser may be used. This is similar to the light emitting diode 14.
[0020]
【The invention's effect】
As is apparent from the above description, the present invention converts the pulse light emitted from one or a plurality of projectors provided in the external communication opening of one or a plurality of flow paths formed inside the cast product into another external light. The light is received by the omnidirectional light receiving surface of one light guide member provided in the communication opening, and then guided to the light receiver provided at the end of the light guide member, and the light output detected by the light receiver is compared with a threshold value. By performing the pass / fail determination, it is possible to detect the degree of obstruction of the flow path due to light that cannot be detected in the past because the flow path is rough and light attenuation is large. Moreover, since the light is received by the omnidirectional light receiving surface, undetected transmitted light can be prevented, and the degree of blockage of a plurality of flow paths can be detected by one light guide member. In addition, by emitting pulsed light from the light projector, light reception data for each flow path can be clearly identified, and high detection accuracy can be obtained.
By making the light guide member a light guide fiber bundle as in claim 3, the light guide member can be more resistant to impact than transparent glass or transparent resin, and can be easily mounted on the test object. Become. In addition, if the length of the light-guiding fiber bundle is extended, the light receiver can be separated from the object to be inspected, so that the light receiver is not damaged by mistake during the inspection, so that it can be used for a long time and the running cost can be reduced.
Since the omnidirectional light receiving surface is formed of a conical ground glass portion as described above, even a small amount of light can be reliably received, so that the light receiving ability can be enhanced.
By making the base end diameter of the light guide member smaller than the diameter of the shaft portion, the passing light is concentrated and the luminance is increased, so that the detection accuracy can be improved. For this reason, a small-sized photodetector having a low detection ability can be used, so that the cost is low.
According to the sixth aspect of the present invention, the light emitting device is formed of a light emitting diode, so that the device can be made extremely inexpensive as compared with a laser or the like.
According to a seventh aspect of the present invention, the plurality of projectors emit pulse light at a timing not overlapping with each other by the pulse distribution circuit, so that the peak output can be increased and the pulse light can have high brightness. It has various advantages such as the ability to continuously inspect the road.
Therefore, the present invention is extremely significant in that it contributes to the development of the industry as a method for inspecting defective molding holes in cast products, which solves the conventional problems.
[Brief description of the drawings]
FIG. 1 is a partially cutaway plan view of a preferred embodiment of the present invention.
FIG. 2 is a sectional view taken along the line AA in FIG. 1 of a preferred embodiment of the present invention.
FIG. 3 is a block circuit diagram of a preferred embodiment of the present invention.
FIG. 4 is a light guide member used in a preferred embodiment of the present invention.
(A) Front view (b) Side view FIG. 5 shows another light guide member used in a preferred embodiment of the present invention.
(A) Front view (b) Side view FIG. 6 is a plan view showing a light projection range of a light projector used in a preferred embodiment of the present invention.
FIG. 7 is a graph showing a light receiving output detected by the light receiving device.
FIG. 8 is a graph showing a variation in output voltage at a flow path blockage level.
FIG. 9 is a diagram illustrating the principle of an apparatus in which an experiment for measuring the output of received pulsed light is performed using a square pipe that can be narrowed.
FIG. 10 is a graph showing a relationship between an aperture ratio and a received light output by an experiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Projector 12 Pulse distribution circuit 14 Light emitting diode 20 Light guide member 21 Omnidirectional light receiving surface 30 Light receiver

Claims (7)

Pulse light emitted from one or more light emitters provided in one or more external communication openings of one or more flow paths formed inside the cast molded product is supplied to one light guide member provided in another external communication opening. Casting characterized by receiving light on an omnidirectional light receiving surface, guiding the light to a light receiver provided at the end of the light guide member, and comparing the light reception output detected by the light receiver with a threshold value to judge pass / fail. Inspection method for defective holes in molded products. The method according to claim 1, wherein the light guide member is a transparent glass or a transparent resin. The method according to claim 1, wherein the light guide member is a light guide fiber bundle. 4. The method according to claim 1, wherein the omnidirectional light receiving surface is formed of a substantially conical ground glass portion. 5. The method according to claim 1, wherein the base end diameter of the light guide member is smaller than the shaft diameter. 6. The method according to claim 1, wherein the floodlight comprises a light emitting diode. 7. The method according to claim 1, wherein the plurality of light emitters emit pulse light at a timing at which the light is not overlapped by the pulse distribution circuit.

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