JP2007108102A - Flow-rate-type performance inspection device and inspection method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection device which needs no change of setting for each volume of an object to be inspected. <P>SOLUTION: A test pressure specified by a pressure control valve 2 is introduced in an object W to be inspected via a pressure introducing path 3L. The path 3L is branched to a first shunt 31 and a second shunt 32; when pressurizing, a first valve V31 is closed and a second valve V32 is opened; thereafter the first valve V31 is opened and the second valve V32 is closed; and then a flow rate is measured by a flow meter T31 in the first shunt 31. Based on the measured flow rate, a performance inspection is conducted for leakage of the object W to be inspected and distributability thereof. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus and an inspection method for introducing a test pressure into an inspection object and inspecting performance such as pass / fail of the inspection object (existence of leakage or the like) and gas channel flowability.

For example, some semiconductor parts and automobile parts have a sealed space. When inspecting this sealed state, a differential pressure type leak inspection is generally performed. In the differential pressure type leak inspection, a pressurized gas having an equal pressure is introduced into these two spaces in a state where the space including the inspection target (work) and the space including the reference (master) are communicated. Thereafter, the two spaces are blocked from each other to form a closed system, and a differential pressure between the two spaces is detected using a differential pressure sensor. Thereby, it is possible to detect the presence or absence of leakage of the inspection target, and to determine whether the inspection target is in a sealed state, and thus whether the inspection target is good or defective.
JP 2004-6201 A

In the differential pressure type inspection, it is necessary to convert the obtained differential pressure into a flow rate. For conversion, the volume to be inspected is used as a coefficient. For this reason, it is necessary to switch the conversion coefficient every time the volume to be inspected is different. Grape management for each volume to be inspected is also necessary and complicated. When there is variation in the volume of the inspection object, it becomes difficult to cope with it.
In addition, in the differential pressure type inspection apparatus, it is not possible to examine the flowability of the gas passage by using a part having a gas passage with an open end, such as an automobile muffler, as an inspection target.

The present invention is an apparatus for performing performance inspections such as pass / fail of the inspection object from the leakage or distribution degree of the inspection object,
A pressure introduction path for introducing the test pressure set by the pressure control valve into the inspection target;
A flow meter provided in the pressure introduction path;
With
The performance inspection is performed based on a measured flow rate of the flowmeter under the test pressure.
Further, the present invention is a method for performing a performance inspection of the inspection object from a leakage or distribution degree of the inspection object,
A pressurizing step of introducing a predetermined test pressure from the pressure introduction path to the inspection object;
A detection step of measuring a flow rate of the pressure introduction path under the test pressure;
And the measured flow rate contributes to the performance inspection.
This eliminates the need for conversion, and it is not necessary to change the setting for each volume to be inspected, and it is possible to accurately inspect an inspection object having a variation in volume. The present invention can be applied not only to leakage inspection of sealed spaces but also to inspection of gas channel flowability.
“Performance inspection of inspection object” means that the inspection object that should have a sealed space is inspected for the quality of the sealed state, or the inspection object having a gas passage such as an automobile muffler is the flowability (conductance) of the gas passage. Including inspection.

A pressure introduction path downstream from the pressure control valve has a first branch path and a second branch path that bypasses the first branch path;
The flow meter and the first on-off valve are provided in the first branch channel,
It is preferable that a second on-off valve is provided in the second branch channel.
When applying the test pressure to the inspection object, it is preferable to open the second on-off valve with the first on-off valve closed, and then open the first on-off valve. Thereby, it can prevent that an excessive flow volume flows into a flowmeter, or can prevent a foreign material from mixing in, and can protect a flowmeter.

A pressurizing step of opening the second on-off valve in a state in which the first on-off valve is closed, and introducing a test pressure from the second branch flow path to a test object;
A first balancing step that also opens the first on-off valve;
A second equilibration step of closing the second on-off valve with the first on-off valve open;
A detection step of measuring the flow rate of the first diversion channel with the flow meter while maintaining the introduction state of the test pressure from the first diversion channel to the inspection object by the second equilibrium step;
Are sequentially executed, and the performance inspection of the inspection object is preferably performed based on the measured flow rate of the flowmeter.
As a result, it is possible to prevent the excessive flow rate and foreign matter from entering the flow meter during the pressurization process, protect the flowmeter, and place the first equilibrium process and the second equilibrium process between the pressurization process and the detection process. Therefore, the disturbance caused by the valve opening / closing operation can be converged, and the accuracy of the inspection can be improved.

Usually, there are a plurality of inspection objects of the same kind.
In this case, the time-dependent change data of the measured flow rate after the pressurizing step is stored for one of the plurality of inspection objects, and the measurement flow rate obtained in the detection process is stored for the remaining inspection objects. It is preferable to correct based on the data, and to use the corrected measured flow rate for the performance inspection.
Thereby, the disturbance resulting from the heat dissipation after the adiabatic compression in the pressurizing step can be corrected, and the accuracy of the inspection can be improved.

The time-varying data is the difference between the average value of the measured flow rate during the heat release period when the flow rate decreases with the heat release after the pressurizing step and the measured flow rate during the stable period when the flow rate becomes substantially constant after the heat release period. ,
It is more preferable to obtain the corrected measured flow rate by performing a detection step for the remaining inspection objects during the heat dissipation period and subtracting the difference from the average value of the measured flow rates.
Thus, if one of the inspection objects is subjected to flow measurement over a long period of time, the remaining inspection objects can be inspected during the heat dissipation period, and the overall required inspection time can be shortened.

  According to the present invention, since the flow rate can be obtained directly, there is no need for conversion. Therefore, it is not necessary to change the setting even if the volume of the inspection object is different, and it is possible to accurately inspect an inspection object having a variation in volume.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a flow rate type performance inspection system. This system includes a pressurizing source 1, a pressure control valve 2, and a flow rate type performance inspection device 3.
For example, an air compressor is used as the pressure source 1. A pressure passage 10 extends from the pressure source 1. The pressure control valve 2 is provided in the pressurizing passage 10. By adjusting the spring force of the pressure control valve 2, the secondary pressure (system test pressure) of the pressure control valve 2 can be set. An electromagnetic pressure control valve may be used as the pressure control valve 2, and the test pressure may be controlled to be predetermined based on a detection value of the pressure sensor S31 described later.

  The flow rate type performance inspection device 3 has a test pressure introduction path 3L. The test pressure introduction path 3L includes a pressure source connection path 30, and a first branch path 31 and a second branch path 32 branched from the pressure source connection path 30. An inlet port P30 is provided at the upstream end of the pressure source connection path 30. The downstream end of the pressurizing path 10 is connected to the inlet port P30. The pressure source connection path 30 is provided with a filter F30. A first branch path 31 and a second branch path 32 are branched from the pressure source connection path 30 downstream from the filter F30.

A pressure sensor S31, a flow meter T31, and a first on-off valve V31 are sequentially provided in the first branch channel 31 from the upstream side.
As the first on-off valve V31, a normally closed electromagnetic on-off valve that is closed when turned off and opened when turned on is used.

  The second branch path 32 is a bypass path that bypasses the flow meter T31 of the first branch path 31. The second branch channel 32 is provided with a second on-off valve V32. As the second on-off valve V32, a normally closed electromagnetic on-off valve that is closed when off and opened when on is used.

The first branch flow path 31 and the second branch flow path 32 merge with each other, and the work connection path 33 extends therefrom. A filter F33, a work port valve V33, and a work port P33 are sequentially provided in the work connection path 33 from the upstream side. The inspection object W (work) is connected to the work port P33.
The inspection target W is, for example, a semiconductor component having a sealed space or an automobile component having a sealed space or a gas passage. The work port P33 may be communicated with the sealed space or the gas passage of the inspection target W, or the inspection target W having the sealed space may be accommodated in a capsule, and the work port P33 may be communicated with the capsule.

A calibration path 34 and an exhaust path 35 are branched and extended from the work connection path 33 upstream of the filter F33. The calibration path 34 is provided with an on-off valve V34. As the on-off valve V34, a normally closed electromagnetic on-off valve that is closed when turned off and opened when turned on is used.
The exhaust passage 35 is provided with an on-off valve V35. As the on-off valve V35, a normally-open electromagnetic on-off valve that opens when turned off and closes when turned on is used.

  Although illustration is omitted, the flow rate type performance inspection system is provided with a control means for operating the valves V31 to V35 and performing predetermined processing based on the measurement results of the flowmeter T31 and the sensor S31.

A method for performing the performance inspection of the inspection object W using the system having the above configuration will be described with reference to the time chart of FIG.
Test pressure setting step The test pressure is set in advance by adjusting the spring of the pressure control valve 2. The setting may be performed with reference to the reading of the pressure sensor S31.

The inspection object W is connected to the connection process work port P33.
All four electromagnetic on-off valves V31, V32, V34, and V35 are turned off. Therefore, the electromagnetic on-off valves V31, V32, V34 of the first and second branch paths 31, 32 and the calibration path 34 are closed, and only the electromagnetic on-off valve V35 of the exhaust path 35 is open.
The work port valve V33 is opened.

Pressurizing step next executes a pressurized process. In the pressurizing step, the second on-off valve V32 of the second branch passage 32 is turned on and opened, and the on-off valve V35 of the exhaust passage 35 is turned on and closed. Thereby, the compressed air of the pressurizing source 1 is adjusted to a predetermined test pressure by the pressure control valve 2 and then introduced into the inspection object W through the second branch channel 32. The first on-off valve V31 of the first branch channel 31 is kept off and kept closed. Therefore, compressed air during pressurization does not pass through the first branch channel 31. As a result, it is possible to prevent an excessive flow rate from flowing into the flow meter T31 or to prevent foreign matter from entering the flow meter T31, thereby protecting the flow meter T31.

After the applied pressure of the equilibrium process inspection object W reaches the test pressure, the equilibrium process is executed. The equilibration process has two stages, a first equilibration process and a second equilibration process.
In the first equilibration step, the first on-off valve V31 of the first diversion channel 31 is turned on and opened while the second on-off valve V32 of the second diversion channel 32 is kept open. As a result, the compressed air flows not only through the second branch channel 32 but also through the first branch channel 31.

After a few seconds, move on to the second equilibration step. In the second equilibration step, the second on-off valve V32 of the second branch passage 32 is turned off and closed while the first on-off valve V31 of the first branch passage 31 is kept open. As a result, the compressed air is introduced into the inspection object W through only the first branch channel 31 of the first branch channel 31 and the second branch channel 32. The time for the second equilibration step is a few seconds.
Disturbances associated with valve opening and closing are settled by this balancing process.

After completion of the detection process equilibration process, the detection process is started. In the detection step, the flow rate of the first branch channel 31 is measured by the flow meter T31.
In the case of an inspection object W having a sealed space such as a cylinder block of a semiconductor package or an automobile engine, if there is no leakage from the sealed space, no flow occurs and the flow rate becomes zero. On the other hand, if there is a leak, an air flow from the pressure source 1 to the inspection object W occurs through the first branch flow path 31, and this air flow rate is detected by the flow meter T31. Thereby, the leakage of the inspection object W can be detected, and the quality of the inspection object W can be determined based on the detected flow rate.
In the case of an inspection target W having a gas passage such as an automobile muffler, air from the pressurization source 1 flows through the gas passage through the first branch passage 31, and this air flow rate is detected by the flow meter T31. Thereby, the flowability of the gas passage of inspection object W can be investigated.

Since the flow rate (including leakage) that is the target of performance evaluation can be obtained directly, there is no need for conversion. Therefore, it is not necessary to change the setting even if the volume of the inspection object W is different. It is possible to accurately inspect the inspection target W having a variation in volume.
According to the flow meter T31, it is possible to sufficiently cope with a large leak (large flow rate) that is difficult to detect with a differential pressure sensor.

After completion of the post-process detection step, the first on-off valve V31 of the first branch passage 31 is turned off and the on-off valve V35 of the exhaust passage 35 is turned off to exhaust the test pressure introduction passage 3L. Further, the inspection object W is taken out.

Next, an improved aspect of the inspection method will be described.
In the pressurizing step, heat is generated in the system by adiabatic compression. Then, heat is dissipated. This heat generation and heat dissipation becomes a disturbance of flow measurement. On the other hand, if the detection process is performed after the disturbance has converged, the inspection takes time.
Therefore, it is desirable to obtain the influence of the heat as correction data in advance as follows and perform an inspection in consideration of the correction data in an actual inspection.

The basic operation of the preliminary inspection is the same as that in the first aspect. That is, after setting the test pressure (test pressure setting process), one inspection object W is connected to the work port (connection process), the test pressure is introduced to the inspection object W (pressurization process), After waiting for the turbulence to settle (first equilibrium step and second equilibrium step), detection is performed (detection step).

  FIG. 3 shows an example of the change over time of the flow rate in the first branch channel 31 after the second equilibration step. The flow rate rises steeply and reaches a peak, then gradually decreases due to the effect of the heat dissipation, and eventually settles to a constant value. Hereinafter, a period from rising to reaching a peak is referred to as a rising period, a period gradually decreasing from the peak is referred to as a heat dissipation period, and a period after reaching a substantially constant value is referred to as a stable period.

The detection process in the preliminary inspection is performed over a relatively long time from the heat dissipation period to the stable period. As a result, flow rate data during the heat dissipation period and flow rate data during the stable period are obtained.
During the heat dissipation period, the flow rate is sampled at regular intervals. And the average value of the sampling data of these heat dissipation periods is calculated | required. For example, the flow rate is sampled every 0.1 seconds. If the heat dissipation period is 5 seconds, 50 sampling data are obtained. The sum of these 50 data is taken and divided by 50 to obtain an average value.
The flow rate value during the stable period is subtracted from the average value during this heat dissipation period. The value obtained by subtraction is stored as a correction value (flow rate change data).
The inspection object W used in the preliminary inspection is not limited to a non-defective product but may be a defective product. A thing equivalent to the inspection object W may be used.

This test is then run this test for the remaining inspection object W.
In this inspection, the rising period in the preliminary inspection is set as the time of the second equilibrium process. Further, the entire period of the heat radiation period or the middle of the heat radiation period is set as the time for the detection process. Then, as in the first aspect, the work is connected to the work port (connection process), the set pressure is introduced into the inspection object W (pressurization process), and after waiting for an equilibrium state (equilibrium process), detection is performed. (Detection step).

In the detection process, the flow rate is sampled at regular intervals. And the average value of these sampling data is calculated | required. For example, sampling is performed every 0.1 second for 5 seconds to obtain 50 sampling data, and the sum of these 50 data is taken and divided by 50 to obtain an average value. This average value is taken as the actual flow rate measurement value of the inspection object W.
Subtract the correction value obtained in the previous inspection from the actual flow rate measurement value. Thereby, disturbance due to heat radiation can be removed from the actual flow rate measurement value, and the net flow rate (leakage) of the inspection object W can be obtained.
According to this improvement mode, the detection process can be executed without waiting for the heat dissipation to converge, so that the entire required inspection time can be greatly shortened.

  The present invention is not limited to the above embodiment, and various modifications can be made.

  The present invention detects the leakage of an inspection target W that should have a sealed space such as a semiconductor part or an automobile part to determine whether the inspection target W is acceptable or not, and the flowability of the inspection target W having a gas passage such as an automobile muffler. It can be applied to the inspection.

1 is a circuit diagram showing a schematic configuration of a flow rate type performance inspection system according to an embodiment of the present invention. It is a time chart of the on-off valve when performing the performance inspection of the inspection object W in the flow rate type performance inspection system. It is a graph which shows an example of a time-dependent change of the flow rate in the 1st distribution channel after the 2nd equilibration process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressurization source 10 Pressurization path 2 Pressure control valve 3 Flow type performance inspection apparatus 3L Test pressure introduction path 31 1st branch path 32 2nd branch path S31 Pressure sensor T31 Flowmeter V31 1st on-off valve V32 2nd on-off valve W Inspection target

Claims (6)

An apparatus for performing a performance inspection of the inspection object from a leakage or distribution degree of the inspection object,
A pressure introduction path for introducing the test pressure set by the pressure control valve into the inspection target;
A flow meter provided in the pressure introduction path;
With
A flow rate type performance inspection apparatus that performs the performance inspection based on a measured flow rate of the flowmeter under the test pressure. A pressure introduction path downstream from the pressure control valve has a first branch path and a second branch path that bypasses the first branch path;
The flow meter and the first on-off valve are provided in the first branch channel,
The flow rate type performance inspection apparatus according to claim 1, wherein a second on-off valve is provided in the second branch flow path. A method for performing a performance inspection of the inspection object from a leakage or distribution degree of the inspection object,
A pressurizing step of introducing a predetermined test pressure from the pressure introduction path to the inspection object;
A detection step of measuring a flow rate of the pressure introduction path under the test pressure;
The flow rate type performance inspection method is characterized in that the measured flow rate is contributed to the performance inspection. Using the flow rate type performance inspection device according to claim 2,
A pressurizing step of opening the second on-off valve in a state in which the first on-off valve is closed, and introducing a test pressure from the second branch flow path to a test object;
A first balancing step that also opens the first on-off valve;
A second equilibration step of closing the second on-off valve with the first on-off valve open;
A detection step of measuring the flow rate of the first diversion channel with the flow meter while maintaining the introduction state of the test pressure from the first diversion channel to the inspection object by the second equilibrium step;
Are sequentially executed, and the performance inspection of the inspection object is performed based on the measured flow rate of the flowmeter. There are a plurality of inspection objects of the same type, and for one of the plurality of inspection objects, data of change over time of the measured flow rate after the pressurizing step is stored,
5. The flow rate according to claim 3, wherein the measurement flow rate obtained in the detection step for the remaining inspection object is corrected based on the temporal change data, and the corrected measurement flow rate contributes to the performance inspection. Formula performance inspection method. The time-varying data is the difference between the average value of the measured flow rate during the heat release period when the flow rate decreases with the heat release after the pressurizing step and the measured flow rate during the stable period when the flow rate becomes substantially constant after the heat release period. ,
The detected flow rate after correction is obtained by executing a detection step for the remaining inspection object during a heat dissipation period and subtracting the difference from the average value of the measured flow rate. Flow type performance inspection method.

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