JP4005880B2 - Quality inspection equipment - Google Patents

Description

【００３５】
表１及び図７から分かるように、クラックのない被検査部材の出力ピークは四角枠内にあり、クラックのない被検査部材の出力ピークは四角枠外にあるので、これを比較演算回路にて比較判別することでクラックの有無を判別し、選別機構にて良品と不良品に仕分けることができた。
【００３６】
[実施例２]
本発明の品質検査装置を用いて厚み寸法に差のある被検査部材を適当に混合させてそれぞれの周波数波長と周波数出力の違いを確認した。被検査部材としては、外径２５ｍｍ、内径２０ｍｍファルステライトセラミックス（比重２．８）からなるリング状ワークを用い、その厚み寸法は１．９ｍｍ〜２．１ｍｍのものを適当に混合させた。
【００３７】
予め実験により被検査部材の重量下限値０．９７５ｇのピーク周波数波長であった１．１ｋＨｚ、上限値１．０２５ｇのピーク周波数波長であった１．３ｋＨｚの範囲を第２の範囲（第３の範囲）として設定した。
【００３８】
このリング状ワーク１０００個についてクラックの有無の検査と重量規格０．９７５〜１．０２５ｇの品質検査により良品、不良品の仕分けを行い、良品、不良品のリング状ワークについて検査員がクラックの目視検査と重量検査を再確認したところ、判定ミスなく作業が完了していた。
【００３９】
また、リング状ワークの断面形状と比重は一定であったので、その厚み寸法を計算することができ、厚み寸法１．９５ｍｍ〜２．０５ｍｍの寸法判定による品質検査をも行えた。
【００４０】
【発明の効果】
以上説明したように、本発明によれば、人の聴覚に頼ることなくクラック検査を自動で行うことができるので、より効率的で生産性を向上させることができる品質検査装置を提供することができる。
【００４１】
また、クラックのない良品と判定した被検査部材について、光学式センサやレーザなどのセンサを用いることなく生産ライン上で被検査部材の重量や厚み寸法も同時に検査が可能な品質検査装置を提供することができる。
【図面の簡単な説明】
【図１】本発明のクラック検査機を説明する工程図である。
【図２】本発明のクラック検査機を説明するブロック図である。
【図３】クラックのない被検査部材Ｐの振動音を集音した波形の集音特性を示す図である。
【図４】（ａ）はクラックのない被検査部材について、その重量に差がある場合の振動音を集音した波形の周波数特性図であり、（ｂ）はその第２の範囲における拡大した周波数特性図である。
【図５】クラックのない被検査部材の周波数特性を示す図である。
【図６】クラックのある被検査部材の周波数特性を示す図である。
【図７】クラックがある被検査部材の出力ピークとクラックがない場合の被検査部材の出力ピークを示す図である。
【符号の説明】
Ｐ：中央に貫通孔を有する平板状の被検査部材
１：投入ホッパー
２：パーツフィーダ
３：直進フィーダ
４：落下シュート
５：検査基板
６：マイクロフォン
７：周波数アナライザ
８：比較演算回路
９：選別機構（判別アクチュエータ）[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a quality inspection apparatus for quickly discriminating cracks, weights, and thicknesses of a plate-shaped inspected member having a through hole in the center, and in particular, seals used for spacers and various pumps used in hard disk devices. The present invention relates to a quality inspection apparatus capable of performing a quality inspection of a ring at high speed.
[0002]
[Prior art]
Conventionally, as a method for inspecting a crack in a product, a discrimination method called a red check inspection in which a crack detection liquid is soaked into a crack portion and an appearance inspection of the crack is performed.
[0003]
In this method, it is difficult to discriminate small cracks, and the skill of an inspector is required, which is unsuitable as a method for inspecting a large amount of products.
[0004]
As a method of inspecting cracks in a flat plate-shaped inspected member having a through hole in the center, a flat plate-shaped inspected member having a through hole in the center is dropped on the inspection substrate, and the vibration sound is discriminated by hearing the vibration sound. There was also a method of inspection. This method is characterized by the fact that a product with no cracks emits a vibration sound called “Chilelein”, whereas a product with cracks leading to the inside and outside of the through-hole has low and dull vibrations. It was discriminating and distinguishing.
[0005]
As a quality inspection method using such vibration sound, there is a method of performing a flaw detection test using a frequency analyzer by hitting the state of a mortar of a tile attached to the outer wall of a building with a hammer (see Japanese Patent Laid-Open No. 9-152427). ).
[0006]
On the other hand, as a method of selecting the weight and thickness on the production line, a weight meter, an optical sensor, or a sensor using a laser is installed on the line passing through the member to be inspected, and the sensor detects it. There was a method of determining the thickness within the range.
[0007]
[Problems to be solved by the invention]
In the above-described method of performing crack inspection by distinguishing vibration sound by human hearing, skill is required for distinguishing vibration sound, and when performing a large number of crack inspection, human error occurs and lacks reliability. It was.
[0008]
In addition, the method of performing a flaw detection test using a frequency analyzer by hitting the mortar state with a hammer is not a productive method because of poor determination efficiency.
[0009]
Furthermore, as a method of selecting weight and thickness on the production line, measurement errors are large and it is difficult to obtain accurate numerical values.
[0010]
[Means for Solving the Problems]
In the present invention, in view of the above problems, a member to be inspected, which is a flat plate-like ceramic member having a through-hole in the center, is used to collect vibration noise generated by dropping the member to be inspected onto an inspection substrate. The frequency range and the frequency output range are determined based on the sound machine, the frequency analyzer for detecting the frequency output peak of the vibration sound and the frequency wavelength thereof, the output peak of the vibration sound of the member to be inspected without cracks and the frequency in advance. A comparison operation circuit that determines whether or not there is a crack depending on whether or not the detection value of the frequency analyzer falls within the first range, and a member to be inspected is a non-defective product based on the determination result of the comparison operation circuit And a sorting mechanism for sorting into defective products, wherein the comparison operation circuit is a non-defective inspected member in advance for a non-defective inspected member determined to have no cracks. A second range is determined from the output peak of the vibration sound of the volume lower limit value and its frequency and the output peak of the vibration sound of the weight upper limit value and its frequency, and whether or not the detected value of the frequency analyzer falls within the second range. Is a circuit for discriminating a member to be inspected having a predetermined weight value by determining the output peak of vibration sound at the weight lower limit value, its frequency, and the member having the same cross-sectional area and specific gravity in advance. A third range in thickness is determined from the output peak of vibration sound of weight upper limit value and its frequency, and it is determined whether or not the detected value of the frequency analyzer falls within the third range. A quality inspection apparatus characterized by being a circuit for discriminating members.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention will be described in detail below based on specific embodiments shown in the accompanying drawings.
FIG. 1 shows a configuration diagram of a quality inspection apparatus according to the present invention.
The quality inspection apparatus includes a hopper 1 formed at the upper part, a parts feeder 2 for separating and aligning the inspection target P arranged at the lower part of the hopper 1, a linear feeder 3 for conveying the inspection target P discharged from the part feeder 2, A dropping chute 4 for inspecting cracks by dropping the member P to be inspected of the linear feeder 3, a test substrate 5 for generating a falling vibration sound by landing the dropped inspection member P, and collecting the vibration sound. It is composed of a sound collector (hereinafter referred to as a microphone), a frequency analyzer 7, a comparison operation circuit 8, a sorting mechanism 9 for sorting the member P to be inspected into a non-defective product and a non-defective product, and a sorting box 9a for storing the defective product and the non-defective product. Yes.
[0014]
As shown in FIG. 1, the member P to be inspected is a flat ceramic member having a through hole in the center, and is formed of alumina, zirconia, aluminum nitride, or the like, for example.
[0015]
The inspection substrate 5 is preferably a material having high rigidity and wear resistance such as alumina ceramic or sapphire. Further, the collision surface of the inspection substrate 5 is arranged so that the collision surface is inclined in the direction in which the member to be inspected P is discharged, as shown in FIG. Thus, the flow of the member P to be inspected on the production line can be made smooth, and the inspection time can be shortened.
[0016]
And about the operation | movement of a quality inspection apparatus, the to-be-inspected member P is thrown into the hopper 1, the to-be-inspected member P is separated and aligned from the hopper 1 with the parts feeder 2, and it is serially connected one by one with the linear feeder 3 The aligned members to be inspected P are passed through the drop chute 4 one by one and dropped onto the inspection substrate 5. The vibration sound generated at that time is collected by the microphone 6, the frequency output peak and its frequency wavelength are detected by the frequency analyzer 7, and the detected value is determined in advance by the comparison operation circuit 8. It is determined whether or not the frequency range and the frequency output range are entered, and the determination result is sent to a discrimination actuator of the selection mechanism 9 so that the non-defective product and the defective product are sorted and sorted into the sorting box 9a.
[0017]
The time required for the pass / fail judgment and the operation time of each drive unit, transport, and actuator are configured to be 0.5 seconds or less per member to be inspected.
[0018]
Next, a more specific crack inspection method for performing crack inspection, weight inspection, and thickness inspection will be described with reference to the flowchart of FIG.
First, the member P to be inspected is dropped onto the inspection substrate 5, and the vibration sound emitted from the member P to be inspected several msec to several tens of msec from the time when the member P to be inspected has generated a vibration sound reaching the inspection substrate 5. Is collected by the microphone 6. The sound collection timing at this time is monitored by the pickup sensor 10, the signal is further sent to the control circuit 11, and the input timing is selected by the trigger circuit 12. At the same time, the input signal collected from the microphone 6 is amplified by the amplifier 13, unnecessary frequency bands are removed by the high-pass filter 14, and the frequency characteristic of the vibration sound, that is, the frequency output peak is obtained by the frequency analyzer 7. Detect the value and its frequency wavelength.
[0019]
In this case, the member P to be inspected is dropped on the inspection substrate 5, and the frequency characteristic of the member P to be inspected without a crack becomes a waveform having a peak of the frequency output peak as shown in FIG. The characteristics appear such that the frequency output peak at the frequency of the frequency output peak is completely different as shown in FIG.
[0020]
By the way, in general, the vibration sound of the member P to be inspected without a crack has a high frequency output peak value, and the vibration sound of the member P to be inspected with a crack has a frequency output peak value of 10 dB or more. In the invention, using this feature, it is possible to obtain the output peak of the vibration sound of the member P to be inspected without a predetermined crack and the frequency thereof as a first range by experiment, and to perform quality inspection with few determination errors. In the present invention, this first range is frequently registered in the memory 15.
[0021]
For example, FIG. 3 is a diagram showing a sound collecting characteristic obtained by collecting vibration sound of the member P to be inspected without cracks, and the mark ● represents the detected frequency output peak value. The range enclosed by the rectangular frame is the output peak value of the vibration sound of the member to be inspected without a crack and the frequency thereof, and the first range is determined based on this. For example, this output peak and the frequency range before and after the frequency are shown as a frequency range and a frequency output range, and the first range is shown in a straight square frame, and whether or not the peak value actually detected by the frequency analyzer 7 is entered is compared and compared. The comparison judgment is done. Thus, the presence or absence of a crack is determined depending on whether or not the detection value of the frequency analyzer 7 falls within the first range.
[0022]
Further, the result of the comparison and determination by the comparison operation circuit 8 is sent to the control circuit 11 as an electric signal (0 · 1 determination), and the selection actuator 9 (selection mechanism) for selecting the member P to be inspected is operated. Sort.
[0023]
Next, a weight inspection can be performed on the member P to be inspected which is judged as a non-defective product having no cracks by the comparison operation circuit 8.
[0024]
That is, the comparison operation circuit 8 can determine not only the presence / absence of cracks as described above but also the weight.
As this determination method, with a non-defective inspected member P in advance, the output peak of the vibration sound at the lower weight limit value, the frequency and the output peak of the vibration sound at the upper weight limit value, and the second range shown below from the frequency. It has established.
[0025]
The second range will be described with reference to FIG. FIG. 4A is an image diagram of a waveform obtained by collecting vibration sound when there is a difference in the weights of the member to be inspected without cracks, and FIG. 4B is an enlarged view in the second range. As shown to (a), the inside of a square dotted line frame shows a 1st range, and the inside of a square straight line frame shows a 2nd range. The ● mark indicates the frequency output peak value when the weight of the member to be inspected is within the specified weight range, and the ■ mark indicates the frequency output peak value when the weight of the member to be inspected is not within the specified weight range. It is.
[0026]
As shown in the figure, the frequency output peak value of the heavy inspected member P has a peak mainly on the left side, that is, at a low frequency position. A peak value appears at. This tendency is such that the peak value of the frequency moves larger as the weight of the member P to be inspected increases. Therefore, the weight determination can be performed from the frequency output peak value obtained by detecting the vibration sound of the member P to be inspected.
[0027]
By utilizing this, a second range further narrowed down than the first range is set. That is, as shown in FIG. 4 (b), in advance, a non-defective member P to be tested has an output peak of vibration noise at its lower weight limit value, an output peak of vibration sound at its frequency value X and upper limit weight value, and its peak. A second range indicated by a square frame is set from the frequency value Y. This second range is also registered in the threshold memory 15, and the comparison operation circuit 8 determines whether or not the detection value of the frequency analyzer 7 falls within the second range. Based on the determination result thus determined, the member P to be inspected is classified into a non-defective product and a defective product by the sorting mechanism 9 simultaneously with the crack inspection. Thus, by classifying on the basis of weight, it is possible to extract a uniform weight with a simple configuration.
[0028]
Next, the thickness of the member to be inspected P for which the above-described weight is selected can be further inspected.
That is, the comparison operation circuit 8 can determine not only the presence / absence of a crack as described above but also the thickness. In this case, the member P to be inspected having the same cross-sectional area and specific gravity is targeted. For example, since the spacer used in the hard disk device is formed by uniaxial pressure molding using a mold, one having the same specific gravity is mass-produced, and the thickness is measured using this.
As this determination method, the thickness dimension of the member to be inspected at the weight lower limit value and the upper limit value is calculated and defined as the third range. The second range of the rectangular dotted line frame shown in FIG. 4B is set based on the range of the cross-sectional area and specific gravity of the member P to be inspected, but the third range has the same cross-sectional area and specific gravity. Since it is set only within the weight range of the inspected member P, the thickness range can be set from this range.
[0029]
The third range is regularly registered in the memory 15, and the comparison operation circuit 8 compares and determines whether or not the frequency wavelength of the member P to be inspected that has entered the frequency analyzer 7 falls within the frequency range. This method is used to sort non-defective and defective products with thickness dimensions.
[0030]
As described above, the embodiment in which only the thickness measurement is performed has been described, but it goes without saying that the weight determination can be performed simultaneously in the same test as the thickness determination. That is, a member P to be inspected having the same cross-sectional area and specific gravity is prepared in advance for those that are determined to be non-cracked non-defective products, and the weight determination and thickness determination are similarly performed on the member P to be inspected. Is possible. Therefore, in this case, the second range and the third range are the same range.
[0031]
【Example】
[Example 1]
Using the quality inspection apparatus of the present invention, a member to be inspected without cracks and a member to be inspected with cracks were appropriately mixed, and the difference in frequency wavelength and frequency output was confirmed.
As the member to be inspected, a ring-shaped workpiece made of Falsterite ceramics (specific gravity 2.8) having an outer diameter of 25 mm, an inner diameter of 20 mm, and a thickness of 2 mm was used.
The frequency range and the frequency output range in the member to be inspected without a predetermined crack were examined, the frequency range was set to 0.6 kHz to 1.7 kHz, and the first range was set to −19 dB to −1 dB.
FIG. 5 shows the frequency characteristics of the member to be inspected without cracks, and FIG. 6 shows the frequency characteristics of the member to be inspected with cracks. These figures show the waveform after 50 msec from the time when the member to be inspected is dropped onto the inspection substrate from the position of 50 mm height of the drop chute to generate the vibration noise. Further, the low frequency region and the high frequency region are attenuated by using a high-pass filter, and this frequency region is cut so as not to affect the determination.
[0032]
As a result of the experiment, the inspected member without cracks in FIG. 5 has a peak value with a high frequency output around the center in the figure, whereas the inspected member with cracks in FIG. I understand that there is no. And the level difference of this frequency output peak value is 15-20 dB, and it turns out that it is a frequency output level sufficient to distinguish the presence or absence of a crack.
[0033]
Evaluation was made for 10 members to be inspected without cracks and 10 members to be inspected with cracks, and the results of examining the frequency output peak and frequency wavelength are shown in Table 1. FIG. 7 shows the output peak of the inspected member without cracks. The figure shows the output peak of the member to be inspected marked with ●, plotted with the mark ■, and the frequency range and frequency output range of the member to be inspected without a crack set in a square frame.
[0034]
[Table 1]

[0035]
As can be seen from Table 1 and FIG. 7, the output peak of the member to be inspected without cracks is within the square frame, and the output peak of the member to be inspected without cracks is outside the square frame. By discriminating, it was possible to discriminate the presence or absence of cracks, and the sorting mechanism could sort them into good and defective products.
[0036]
[Example 2]
Using the quality inspection apparatus of the present invention, members to be inspected having different thickness dimensions were mixed appropriately to confirm the difference between the frequency wavelength and the frequency output. As the member to be inspected, a ring-shaped workpiece made of falsterite ceramics (specific gravity 2.8) having an outer diameter of 25 mm and an inner diameter of 20 mm was used, and a thickness of 1.9 mm to 2.1 mm was appropriately mixed.
[0037]
The range of 1.1 kHz, which was a peak frequency wavelength of 0.975 g lower limit of the weight of the member to be inspected in advance, and the peak frequency wavelength of 1.025 g of the upper limit 1.025 g was previously set in the second range (third Range).
[0038]
The 1,000 pieces of ring-shaped workpieces are classified into non-defective products and defective products by inspection for cracks and quality inspections of weight standards of 0.975 to 1.025 g. When we reconfirmed the inspection and the weight inspection, the work was completed without judgment errors.
[0039]
Moreover, since the cross-sectional shape and specific gravity of the ring-shaped workpiece were constant, the thickness dimension could be calculated, and a quality inspection could be performed by determining the thickness dimension of 1.95 mm to 2.05 mm.
[0040]
【The invention's effect】
As described above, according to the present invention, it is possible to automatically perform a crack inspection without relying on human hearing, so it is possible to provide a quality inspection apparatus that is more efficient and can improve productivity. it can.
[0041]
In addition, a quality inspection device is provided that can inspect the weight and thickness of a member to be inspected on a production line without using a sensor such as an optical sensor or a laser for a member to be inspected determined to be a non-cracking non-defective product. be able to.
[Brief description of the drawings]
FIG. 1 is a process diagram illustrating a crack inspection machine according to the present invention.
FIG. 2 is a block diagram illustrating a crack inspection machine according to the present invention.
FIG. 3 is a diagram showing a sound collection characteristic of a waveform obtained by collecting vibration sounds of a member P to be inspected without cracks.
FIG. 4A is a frequency characteristic diagram of a waveform obtained by collecting vibration sounds when there is a difference in the weights of a member to be inspected without cracks, and FIG. 4B is an enlarged view in the second range. It is a frequency characteristic figure.
FIG. 5 is a diagram showing frequency characteristics of a member to be inspected without cracks.
FIG. 6 is a diagram showing frequency characteristics of a member to be inspected having cracks.
FIG. 7 is a diagram illustrating an output peak of a member to be inspected with a crack and an output peak of the member to be inspected when there is no crack.
[Explanation of symbols]
P: Plate-like inspected member having a through-hole in the center 1: Feeding hopper 2: Parts feeder 3: Straight feeder 4: Drop chute 5: Inspection substrate 6: Microphone 7: Frequency analyzer 8: Comparison operation circuit 9: Sorting mechanism (Distinguishing actuator)

Claims (1)

Using a member to be inspected, which is a flat ceramic member having a through hole in the center, a sound collector that collects vibration sound generated by dropping the member to be inspected onto the inspection substrate, and a frequency output of the vibration sound A frequency analyzer for detecting the peak and its frequency wavelength, a frequency range and a frequency output range are defined as a first range based on an output peak of vibration sound of a member to be inspected without cracks and its frequency in advance, and the frequency analyzer It comprises a comparison operation circuit that determines the presence or absence of cracks depending on whether or not the detected value falls within the first range, and a selection mechanism that sorts the member to be inspected into a non-defective product and a defective product based on the determination result of the comparison operation circuit. In the quality inspection apparatus, the comparison operation circuit is configured to output a vibration sound output peak at a lower limit weight of the non-defective member to be inspected in advance for the non-defective member to be inspected. A second range is determined from the output peak of the vibration sound of the frequency and weight upper limit value and the frequency, and a predetermined weight value is determined by determining whether or not the detection value of the frequency analyzer falls within the second range. It is a circuit for discriminating a member to be inspected, and for a member to be inspected having the same cross-sectional area and specific gravity in advance, an output peak of vibration sound at its lower weight limit and an output peak of vibration sound at its frequency and upper limit weight. A circuit for determining a member to be inspected having a predetermined thickness by determining a third range in thickness from the frequency and determining whether or not a detection value of the frequency analyzer falls in the third range. Quality inspection equipment.

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