JP2019082340A - Inspection method of cast product - Google Patents

Abstract

To provide an inspection method of a cast product which can detect a defect in a deep site in an internal space.SOLUTION: An inspection method of a cast product comprises: a distance measurement step of receiving reflected light Lof laser light Lradiated from a radiating position to a reference surface in a cast product to measure a distance d from the radiating position to a position where the laser light Lis reflected; and a defect determination step of determining that a defect is present in the cast product when the distance d measured in the distance measurement step is smaller than a predetermined distance d.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of inspecting a cast product.

  It is known that a vehicle cylinder head flows a coolant to prevent overheating. A channel for coolant is formed by using a core at the time of casting, but when a defect such as the core is broken during casting occurs, metal flows into the broken place and the channel is clogged Defects will occur. If the flow path is clogged, the cylinder head is not sufficiently cooled, which causes problems such as engine burn-in. For this reason, after casting the cylinder head, it is necessary to perform an inspection to confirm whether a defect such as clogging of the flow path has occurred.

  In Patent Document 1, as a method of inspecting a cast product, when an optical fiber probe including a light emitting unit and a light receiving unit is inserted into the cooling passage, and the light receiving unit receives the reflected light of light emitted from the light emitting unit An inspection method is disclosed that determines that there is a defect such as clogging near the end.

JP, 2008-256683, A

  In the inspection method of the cast product which concerns on patent document 1, the light radiate | emitted from an optical fiber probe is scattered light, and is irregularly reflected in a casting surface. For this reason, when a defect has occurred at a location away from the optical fiber probe, the reflected light from the defect is greatly attenuated with distance, and is difficult to detect. Therefore, in the inspection method of the cast product which concerns on patent document 1, there existed a problem that it was difficult to detect the defect in the deep place of interior space.

  This invention is made in view of such a situation, Comprising: The inspection method of the cast product which can detect the defect in the deep place of interior space is provided.

  In the inspection method of a cast product according to the present invention, the reflected light of the laser beam irradiated from the irradiation position toward the reference surface in the cast product is received, and the distance from the irradiation position to the position where the laser beam is reflected is Providing a distance measuring step of measuring, and a defect judging step of judging that a defect has occurred in the cast product if the distance measured in the distance measuring step is shorter than the predetermined length. , Is a feature.

In the method of inspecting a cast product according to the present invention, since a highly directional laser beam is emitted toward the reference surface in the cast product, even a light reflected at a deep place in the internal space can receive an intensity capable of receiving light. Have. For this reason, the appearance of a deep place in the internal space can be detected.
In this manner, the method of inspecting a cast product according to the present invention can detect a defect deep in the inner space.

  According to the present invention, it is possible to provide a method of inspecting a cast product which can detect a defect deep in the inner space.

It is a figure which shows the whole structure when test | inspecting a cylinder head without a defect by the inspection method of this invention. It is a flowchart showing the embodiment of the inspection method of the cast product concerning the present invention. It is a figure which shows the whole structure when test | inspecting a defective cylinder head with the inspection method of this invention.

Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Further, in order to clarify the explanation, the following description and the drawings are simplified as appropriate.
As a matter of course, the right-handed xyz coordinates shown in FIG. 1 and the other drawings are convenient for describing the positional relationship of components. Usually, the z-axis positive direction is vertically upward, and the xy plane is a horizontal plane, which is common to the drawings.

In the present embodiment, an aspect of inspecting a cylinder head will be described as an example of an inspection method according to the present invention. The cylinder head is a cast product made of a metal such as aluminum or iron, and is a component used to form, for example, a framework of an automobile engine.
FIG. 1 is a view showing an entire configuration when a defect free cylinder head 1a is inspected by the inspection method of the present invention. As shown in FIG. 1, in the present embodiment, the cylinder head 1 a is inspected using the distance measuring device 2, the movable stage 3, and the computer 4.

A cooling passage 11a is provided inside the cylinder head 1a. The cylinder head 1a according to the present embodiment is placed on the installation surface such that the longitudinal direction of the cooling passage 11a is parallel to the x-axis. In order to reproducibly install the cylinder head 1a in a predetermined arrangement, pins and stoppers may be fixed on the installation surface in advance corresponding to the shapes of the peripheral surface and the bottom surface of the cylinder head 1a.
An entrance hole 12a is provided as an opening at one end of the cooling passage 11a in the x-axis direction. The incident hole 12a is preferably a circle of 6.25 mm or more in consideration of the mounting position of the distance measuring device 2 and the dimensional error of the cylinder head 1a.
A reference surface 13a is provided on the surface of the cooling passage 11a facing the incident hole 12a. The reference surface 13a is preferably a surface substantially perpendicular to the x-axis. The reference surface 13a is preferably a square of 6.25 mm or more for the same reason as the incident hole 12a.

The distance measuring apparatus 2 includes a main body 21, an irradiation unit 22 disposed on the side surface of the main body 21, and a light receiving unit 23 disposed adjacent to the irradiation unit 22, and is electrically connected to the computer 4 It is done.
The main body unit 21 transmits and receives signals to and from the irradiation unit 22, the light receiving unit 23, and the computer 4. Irradiation section 22 is internally provided with a laser device and an irradiation lens, and pulse irradiation of laser light L _I receives the illumination signal from the main body portion 21. The light receiving unit 23, inside a light receiving element and a light receiving lens, and transmits the received light signal and receives the reflected light L _R to be described later to the main body portion 21.
Distance measuring device 2 is fixed on the moving stage 3, the irradiation direction of the laser beam L _I is arranged to be directed substantially parallel and the reference plane 13a and the x-axis.

The moving stage 3 is a stage movable in the y-axis direction, and adjusts the position of the distance measuring device 2 fixed on the upper surface. The moving stage 3 may be movable in the z-axis direction.
Computer 4 based on a signal received from the distance measuring device 2, the distance d from the irradiation position of the laser beam L _I position where the laser beam L _I is reflected is measured, have a defect occurs in the cylinder head 1a Determine if there is.

  Here, the entire flow of the inspection method in the present invention will be described with reference to FIG. As shown in FIG. 2, the inspection method of the present invention includes a distance measurement step S1 and a defect determination step S2. The distance measurement step S1 includes steps S11 to S13, and the defect determination step S2 includes steps S21 to S23.

First, detailed steps S11 to S13 of the distance measurement step S1 will be described.
First, in step S11, the main unit 21 transmits an irradiation signal to the irradiation unit 22. Irradiation section 22 receives the irradiation signal to pulse irradiation with laser light L _I toward the reference surface 13a. Laser beam L _I, as shown in FIG. 1, through the entrance aperture 12a enters the cooling passages 11a, when there is no defect in the path of the laser beam L _I reaches the reference surface 13a. Laser beam L _I having reached is reflected by the reference surface 13a, toward the light receiving portion 23 as reflected light L _R.

Next, in step S12, the light receiving portion 23 receives the reflected light _{L R,} and transmits the received signal to the main body portion 21.
Next, in step S13, the main body portion 21 transmits an irradiation signal and the light receiving signal to the computer 4, the computer 4 obtains the flight time t of the laser beam L _I from the phase difference of the irradiation signal and the light receiving signal. Then, the computer 4, the time of flight t, determining the distance d from the irradiation position of the laser beam L _I position where the laser beam L _I is reflected as [d = speed of light × t × 1/2].

If the cylinder head 1a is not defective in the path of the laser beam L _I, as shown in FIG. 1, the distance from the irradiation position to the reference surface 13a is distance d. In the present invention, since the use of highly directional laser light L _I as the detection light can be detected even in reflected light L _R from 500mm away from the irradiation position. That is, it is possible to detect the appearance of a deep place in the inner space.
Of course, the length of the detectable distance d can be extended by increasing the sensitivity of the intensity and the light receiving portion 23 of the laser beam L _I.

Next, detailed steps S21 to S23 of the defect determination step S2 will be described.
First, in step S21, the computer 4 determines whether the distance d is greater than or equal to a predetermined length d _Th . The length d _Th is a threshold that can be arbitrarily set by the user according to the shape of the cylinder head and the depth to be inspected.

If the distance d is equal to or greater than the predetermined length d _Th , the process proceeds to step S22, where the computer 4 determines that no defect occurs in the cylinder head.
On the other hand, when the distance d is shorter than the predetermined length d _Th , the process proceeds to step S23, and the computer 4 determines that a defect is generated in the cylinder head.

As shown in FIG. 1, when a defect in the cylinder head does not occur, the distance d from the irradiation position of the laser beam L _I position where the laser beam L _I is reflected becomes longer than the length d _Th predetermined . Therefore, the computer 4 proceeds from step S21 to step S22 and determines that no defect has occurred in the cylinder head.

On the other hand, the situation in the case where a defect occurs in the cylinder head will be described with reference to FIG. FIG. 3 shows an entire configuration when a cylinder head 1b having a defect C is inspected by the inspection method of the present invention. Cylinder head 1b, similarly to the cylinder head 1a, the cooling passages 11b, entrance aperture 12b, is provided with a reference surface 13b, the cylinder in that position in the defect C of less than the length d _Th distance from the irradiation position occurs It differs from the head 1a. The defect C is, for example, clogging or the like caused by breakage of the core at the time of casting.

As shown in FIG. 3, if there is a defective C in the path of the laser beam L _I, the laser light L _I is reflected by the defect C, it reaches the light receiving portion 23 as reflected light L _R. Therefore, the distance d from the irradiation position of the laser beam L _I position where the laser beam L _I is reflected is shorter than the length d _Th. Therefore, the computer 4 proceeds from step S21 to step S23 and determines that a defect has occurred in the cylinder head.

Thus, in the method of inspecting a cast product according to the present embodiment, the appearance of a deep place in the internal space can be detected by using a laser beam with high directivity. Therefore, it can be determined whether a defect has occurred even in a deep place in the inner space.
As mentioned above, the inspection method of the cast product concerning the present invention can detect the fault in the deep place of interior space.

  In addition, in the inspection method of the cast product according to the present embodiment, since the presence or absence of the defect in the cooling passage is determined by receiving the reflected light of the laser light, the inspection is possible if there is one opening in the cooling passage. is there. Thus, compared to inspection methods for examining defects in the cooling passages, for example by passing light through holes through the cooling passages, the inspection method according to the invention has the advantage that it is not necessary to provide unnecessary openings in the cooling passages. .

Moreover, this invention is not limited to said embodiment, It is possible to change suitably in the range which does not deviate from the meaning.
For example, in the above embodiment, the flight time t is converted into the distance d, and it is determined whether the defect occurs in the cast product by determining whether the distance d is equal to or longer than a predetermined length. It may be determined whether a defect has occurred in the cast product by determining whether time t is equal to or greater than a predetermined time. In this case, the step of converting the flight time t into the distance d can be omitted.

In the above embodiment, the distance measuring apparatus 2 is fixed and the distance d is measured. However, the moving stage 3 is displaced, and the distance d is measured while scanning on the y axis or z axis, and the maximum Whether or not there is a defect in the cylinder head may be determined based on whether or not the value is equal to or greater than a predetermined length d _Th . In this case, it is possible to suppress the measurement error due to the displacement of the installation place of the distance measuring device 2.

1a, 1b cylinder head 2 range finder 3 movable stage 4 computer 11a, 11b cooling passages 12a, 12b incident hole 13a, the light receiving unit 13b reference plane 21 the body portion 22 irradiator 23 C defect d distance L _I laser light L _R reflected light S1 ranging step S2 defect determination step t flight time

Claims (1)

A distance measuring step of receiving the reflected light of the laser light irradiated from the irradiation position toward the reference surface in the cast product and measuring the distance from the irradiation position to the position where the laser light is reflected;
Determining a defect in the cast product if the distance measured in the distance measuring step is shorter than the predetermined length.
Inspection method of cast products.

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