JPH0713563B2 - Inspection method for soldered parts of leaded parts - Google Patents

Description

The present invention relates to an inspection method for inspecting a soldered portion of a leaded component mounted and soldered on a printed wiring board using a three-dimensional stereoscopic image. .

[Prior Art] Inspection of the soldering portion of a leaded component mounted and soldered on a printed wiring board as in Japanese Patent Laid-Open No. 57-208404 has been performed conventionally.
The inspection was performed by a brightness image from a TV camera or a light-section method in which line light is projected from a position with an angle.

[Problems to be Solved by the Invention] However, in these conventional methods, the actual amount of solder is measured, the clinched lead soldering portion is accurately inspected, and the inspection of the soldering portion which is less affected by the displacement of the measurement position is performed. There was a drawback that you couldn't.

The present invention has been made in view of the above problems, and its object is to measure the soldered state of a soldered state by three-dimensionally measuring the soldered portion of a leaded component mounted and soldered on a printed wiring board. It is another object of the present invention to provide a method for inspecting a soldered portion of a leaded component that enables accurate quality determination.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the invention according to claim 1,
Set the height to obtain multiple cross-sectional images in the height direction for the three-dimensional image obtained by three-dimensionally measuring the lead soldering part of the leaded component mounted and soldered on the printed wiring board. , The cross-sectional area is obtained from the cross-sectional images at the set height positions, and the difference between the cross-sectional areas at the height positions where the inner phases of the obtained cross-sectional areas are adjacent to each other is obtained. The solder wetting angle is obtained from the level difference between the height positions, and the quality of the soldering shape is determined from the obtained solder wetting angle.

Further, in the invention according to claim 2, a plurality of cross-sections in the height direction are obtained with respect to a stereoscopic image obtained by three-dimensionally measuring the lead soldering portion of the leaded component mounted and soldered on the printed wiring board. After setting the height for obtaining the image, obtaining cross-sectional images at the multiple height positions that have been set, obtaining the bending direction of the lead from the obtained positions of each cross-sectional image, and then performing the inspection in the soldering inspection process. The position is decided.

According to the third aspect of the invention, it is possible to mount a lead component which is known in advance on a stereoscopic image obtained by three-dimensionally measuring the lead soldering portion of the lead component mounted and soldered on the printed wiring board. After the bending direction of the lead is obtained from the position and the position of the portion showing the maximum height in the soldering area of the leaded component, the inspection position in the soldering inspection process is determined.

In the invention according to claim 4, in the invention according to claim 2 or 3, the inspection line is set in the direction opposite to the bending direction of the lead, and the quality of the soldering shape is determined from the difference value of the height positions on the inspection line. It has a soldering inspection process.

In the invention according to claim 5, in the invention according to claim 2 or 3, the inspection line is set in the direction opposite to the bending direction of the lead, and the curvature of the soldering shape is obtained from the height position on the inspection line for soldering. It has a soldering inspection process for judging the quality of the shape.

[Operation] Since the present invention uses the stereoscopic image obtained by three-dimensional measurement, the quality of the soldered portion can be accurately determined.

In particular, according to the invention described in claim 1, the height for obtaining a plurality of cross-sectional images in the height direction is set for the three-dimensional image obtained by three-dimensional measurement, and the set plurality of heights are set. The cross-sectional area is obtained from the cross-sectional image of the position, the difference between the cross-sectional areas of the height positions where the inner phase of the obtained cross-sectional area is adjacent to each other is obtained, and the difference between the obtained cross-sectional areas and the level difference of the height position are Since the solder wetting angle is obtained and the quality of the soldering shape is determined from the obtained solder wetting angle, it is possible to determine the soldering shape having a good soldering wetting angle.

According to the invention described in claim 2, the height for obtaining a plurality of cross-sectional images in the height direction is set for the stereoscopic image obtained by three-dimensional measurement, and the set height positions are set. After obtaining the cross-sectional images and obtaining the bending direction of the leads from the obtained positions of the respective cross-sectional images, the inspection position in the soldering inspection process is determined, so that the positioning accuracy of the inspection object is not required so much.

According to the third aspect of the present invention, the position of mounting the leaded component, which is known in advance, and the maximum height in the soldering area of the leaded component are shown with respect to the stereoscopic image obtained by three-dimensional measurement. Since the inspection position in the soldering inspection process is determined after the bending direction of the lead is obtained from the position of the portion, the positioning accuracy of the inspection object is not so required as in the invention according to claim 4.

According to the invention as set forth in claim 4, there is provided a soldering inspection process in which the inspection line is set in a direction opposite to the bending direction of the lead and the quality of the soldering shape is judged from the difference value of the height position on the inspection line. Therefore, a good soldering shape can be determined without requiring much positioning accuracy.

According to the invention of claim 5, the inspection line is set in the direction opposite to the bending direction of the lead, and the curvature of the soldered shape is obtained from the height position on the inspection line to judge the quality of the soldered shape. Since it has an inspection process, a good soldering shape can be determined without requiring much positioning accuracy as in the third aspect of the invention.

[Examples] The present invention will be described below with reference to Examples.

FIG. 1 shows the configuration of an inspection system adopting the method of the present invention. The three-dimensional image detection apparatus 1 is for three-dimensionally measuring the lead soldering part of the leaded component mounted and soldered on the printed wiring board. This is a device for measuring three-dimensional data by measuring the height of the lead soldering part of the leaded component on the printed wiring board to be inspected and moving the printed wiring board by the moving mechanism 2 to change the measurement location. I am asking for it. This three-dimensional data is stored in the image memory 3, and the image processing unit 4 makes an inspection decision. The control unit 5 controls the moving mechanism 2, and the overall control unit 6
Is for controlling the entire system such as the three-dimensional image detection device 1, the image memory 3, the image processing unit 4, and the control unit 5.

Next, a first embodiment of the method of the present invention using the above system will be described with reference to the flowchart of FIG.

In the first embodiment, the processing is started in step, the inspection area is set based on the inspection area data taught in advance in step, and the height of the board height detection point is measured in step to determine the board height H ₀ . taking measurement.

Next, in step, the offset height di for obtaining the preset cross-sectional area is added to the substrate height H0,
The level hi (where i = 0 to n) for obtaining the cross-sectional area is determined.

In the next step, the level hd is determined by subtracting α from the substrate height H0. After such determination, in step, the cross-sectional area Sk at the lower level hk is obtained as shown in FIG. 3, and in step, the cross-sectional area Sk and the non-defective product shown in FIG. Compared with the cross-sectional area of the standard,
If the cross-sectional area Sk is smaller than the standard value as shown in FIG. 4 (b), it is determined that there is no solder.

Next, in the step, the cross-sectional area Sd of the hole at the above level hd
Ask for. Since this level hd is lower than the board height H0, the cross-sectional area Sd becomes 0 when good soldering is done, but when the hole is open, the value of the cross-sectional area Sd is preset. It is possible to judge the perforated defect by comparing it with the standard value. The step is a step of judging the perforated defect.

The cross-sectional area Si at each height hi (where i =
0-n) is calculated, and compared with the standard value (cross-sectional area) for judging the lack of solder and defects, if the measured cross-sectional area is smaller than the standard value, it is determined that there is insufficient solder, and then each solder If it is larger than the standard value by comparing with the standard value (cross-sectional area) for determining excess, it is judged that the solder is excessive.

The next step is to find the difference dsi between the cross-sectional areas.

dsi = (Si ₊₁ −Si) / Si In step, comparison with dsi of good soldering shape was obtained, and the ratio was (100−ε ₁ )% to (100−ε ₂ )% (however, ε ₁ , ε If it is not between ₂ > 0), it is determined that the soldering shape is defective.

Si ^1/2 is obtained in the step and Si ₊₁ ^1/2 is obtained in the step. Here, as shown in FIG. 5, each cross-sectional shape is substantially circular if the soldering condition is good, so the cross-sectional area Si
_The following relational expression is established between the respective levels Hi and Hi ₊₁ for which ₊₁ and Si are obtained, and the solder wetting angle θi between i and i + 1
Is θi = tan ⁻¹ {π ^1/2 (Hi−Hi ₊₁ ) / (Si ^1/2 −Si ₊₁ ^1/2 )}.

In step, θi obtained in step (where i = 0 to 0
n) is compared with the wetting angle range of good soldering to determine whether the soldering shape is good or bad. Then, the processes from step to are repeatedly performed until i = 0 is determined in step, and when i = n is determined in step, the inspection process ends.

Second Embodiment In the first embodiment, the quality of the solder amount and the quality of the soldering shape are determined by using the cross-sectional area of the lead soldering portion, but this embodiment uses the bending direction of the lead. is there.

FIG. 6 shows a flowchart of this embodiment, and the embodiment will be described below with reference to this flowchart.

First, the process is started in step, the inspection area is set based on the inspection area data taught in advance in step, and the height of the board height detection point A shown in FIG. 7 is measured in step to determine the board height H0. taking measurement.

In step, the offset height di for obtaining the sectional image preset to the substrate height H ₀ is added, and the level hi for obtaining the sectional image is determined. However, i = 0 to 1.

The cross-sectional area at each level hi is calculated between steps, and the barycentric coordinates (Xgi, Ygi) of each cross-sectional image are calculated in step.
A linear approximation of [indicated by + mark in FIG. 4] is performed to determine the direction B in which the lead is bent.

Next, in a step, a point p on the circumference in the direction of 180 ° with respect to the bending direction B of the lead in the cross section of the uppermost hj is obtained as shown in FIG. In addition, the point q in the direction of 180 ° with respect to the bending direction B of the lead in the cross section of the lowest ha in the step
Ask for.

In the next step, a shoulder inspection line connecting the points p and q is determined.

In the step, the height of the pixel on this inspection line is measured, and in the step, the height of each pixel is compared from the point p to the point q and the height of the good soldering shape is compared to judge the quality of the soldering shape. To do.

If this determination is good, then in step, the inspection is completed after the soldering shape inspection process of the leaded component shown in the flowchart of FIG. 11 or 13.

Third Embodiment In the second embodiment, the bending direction of the lead is determined using a plurality of cross sections, but in the present embodiment, the bending direction of the lead is determined by the maximum height.

This embodiment will be described below with reference to the flowchart of FIG.

First, similar to the second embodiment, the processing is started in steps, the inspection area is set on the basis of the inspection area data taught in advance in the step, and the position C indicating the maximum height in the inspection area shown in FIG. 9 is set in the step. Ask. Here, since the position D of the hole into which the lead leg is inserted is known in advance as relative coordinates with respect to the inspection region, the lead bending direction B shown in FIG. 9 is determined in steps by the positional relationship between the points C and D. .

Next, in step, a point p on the lead foot insertion position D is obtained. Further, in a step, an intersection q between the straight line extending from the point p in the direction opposite to the lead bending direction B and the inspection area is obtained.

In step, the shoulder inspection line is determined by the line connecting points p and q.

In the step, the height of the pixel on this inspection line is measured, and in the step, the height of each pixel is compared from the point p to the point q with the height of the good soldering shape to judge the quality of the soldering shape. .

If this judgment is good, step 1 or FIG.
After the soldering shape inspection process of the leaded component shown in the flowchart of FIG. 13, the inspection is completed.

Next, the inspection method adopted in the soldering shape inspection process used in the above-mentioned second or third embodiment will be described.

FIG. 10 shows the principle of an example of the inspection method, and FIG. 11 shows its flowchart.

The curve a in FIG. 10 shows the soldering up state of the inspection line connecting the point p and the point q, and the curve b in the figure shows the difference value between the two points from the point p to the point q. As is clear from this figure, when soldering is insufficiently wet, there is a part where the difference value shows from a negative value to a positive value, and in the case of a good soldering shape, it falls gently. Therefore, the negative value becomes 0. That is, when the difference value is positive, it becomes defective.

This inspection method will be described with reference to the flowchart of FIG. 11. The inspection process is started in steps, the height hpi of the point pi of the inspection line is determined in steps, and the point pi ₊₁ which is lower than the point pi in the next step is _calculated. , The difference value hpi ₊₁ −hpi of both heights is determined in step, and the positive or negative of the difference value is determined in step. If positive, it is determined to be defective. If it is judged as good in the step, if the judgment in the step is not q = pi _{+ 1} , the process returns to the step and the above process is repeated.
If the determination in step is q = pi _{+ 1} , the inspection process ends in step.

FIG. 13 shows a flowchart of an inspection method for determining a defect in the soldering shape by obtaining the curvature of the inspection line connecting the point p and the point q shown in FIG. Start and p points in steps,
The curvature is calculated from the height data on the inspection line connecting the q points,
In step, the quality of the soldering shape is judged by comparing with the curvature of the good soldering shape, and the process ends in step.

EFFECTS OF THE INVENTION Since the present invention uses a stereoscopic image obtained by three-dimensional measurement, there is an effect that the quality of the soldered portion can be accurately determined.

In particular, the invention according to claim 1 sets a height for obtaining a plurality of cross-sectional images in the height direction with respect to a stereoscopic image obtained by three-dimensional measurement, and sets the height of the set plurality of height positions. The cross-sectional area is obtained from the cross-sectional image, and the difference between the cross-sectional areas of the height positions where the obtained cross-sectional areas are adjacent to each other is calculated. Since the angle is obtained and the quality of the soldering shape is determined from the obtained solder wetting angle, it is possible to determine the soldering shape having a good wetting angle for soldering.

The invention according to claim 2 sets a height for obtaining a plurality of cross-sectional images in the height direction with respect to a stereoscopic image obtained by three-dimensional measurement, and the cross-sections at the set height positions. After the image is obtained and the bending direction of the lead is obtained from the obtained position of each cross-sectional image, the inspection position in the soldering inspection process is determined, so that the positioning accuracy of the inspection object is not required so much.

According to a third aspect of the present invention, with respect to a three-dimensional image obtained by three-dimensional measurement, a known position of mounting the lead-equipped component and a portion indicating the maximum height in the soldering area of the lead-equipped component are displayed. Since the inspection position in the soldering inspection process is determined after the lead bending direction is obtained from the position, there is an effect that the positioning accuracy of the inspection object is not so much required as in the invention according to claim 2.

The invention according to claim 4 has a soldering inspection process in which an inspection line is set in a direction opposite to the bending direction of the leads, and the quality of the soldering shape is judged from the difference value of the height positions on the inspection line. Therefore, there is an effect that a good soldering shape can be determined without requiring much positioning accuracy.

A fifth aspect of the present invention is a soldering inspection process in which an inspection line is set in a direction opposite to a bending direction of leads, and a curvature of the soldering shape is obtained from a height position on the inspection line to determine whether the soldering shape is good or bad. Therefore, similar to the invention described in claim 6, there is an effect that a good soldering shape can be determined without requiring much positioning accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram of an inspection system used in the present invention, FIG. 2 is a flowchart of Embodiment 1 of the present invention, FIG. 3 is an explanatory diagram of the solder shortage inspection of the above, and FIG. FIG. 4 (b) is a sectional view when it is determined to be a defective product, FIG. 5 is an explanatory diagram of the solder wetness inspection above, and FIG. 6 is an embodiment of the present invention. Flowchart of Example 2, FIG. 7 is an explanatory diagram of the same as above, and FIG. 8 is Embodiment 3 of the present invention.
Of FIG. 9, FIG. 9 is an explanatory view of the same as above, FIG. 10 is an explanatory view of the principle of an example of the shape inspection method used in the second or third embodiment, FIG. 11 is a flowchart of the same as above, and FIG. Alternatively, FIG. 13 is a flowchart illustrating the principle of another example of the shape inspection method used in the third embodiment, and FIG. 1 is a three-dimensional image detection device, 2 is a moving mechanism, 3 is an image memory, 4 is an image processing unit, 5 is a control unit, and 6 is an overall control unit.

Claims (5)

[Claims] 1. A three-dimensional image obtained by three-dimensionally measuring a lead soldering portion of a leaded component mounted and soldered on a printed wiring board to obtain a plurality of sectional images in a height direction. The height is set, the cross-sectional area is obtained from the cross-sectional images at the set height positions, and the difference between the cross-sectional areas of the height positions at which the inner phases of the obtained cross-sectional areas are adjacent to each other is obtained, and the obtained disconnection is obtained. A method for inspecting a soldered portion of a leaded component, comprising determining a solder wetting angle from a difference between areas and a level difference of a height position, and determining whether the soldering shape is good or bad from the obtained solder wetting angle. 2. A three-dimensional image obtained by three-dimensionally measuring a lead soldering part of a leaded component mounted and soldered on a printed wiring board to obtain a plurality of cross-sectional images in a height direction. After setting the height, obtaining cross-sectional images at the multiple height positions that have been set, determining the bending direction of the lead from the positions of the obtained cross-sectional images, and then determining the inspection position in the soldering inspection process. A method for inspecting the soldered part of a featured leaded part. 3. A mounting position of a lead-equipped component which is known in advance with respect to a three-dimensional image obtained by three-dimensionally measuring a lead soldering portion of the lead-equipped component mounted and soldered on a printed wiring board. After determining the bending direction of the lead from the position of the portion showing the maximum height in the soldering area of the leaded component, the inspection position in the soldering inspection process is determined. Inspection method. 4. An inspection line is set in a direction opposite to the bending direction of the lead, and a soldering inspection process is provided to judge the quality of the soldering shape from the difference value of the height positions on the inspection line. Item 4. A method for inspecting a soldered part of a component with leads according to item 2 or 3. 5. A soldering inspection process in which an inspection line is set in the direction opposite to the bending direction of the lead, and the curvature of the soldering shape is obtained from the height position on the inspection line to judge the quality of the soldering shape. The method for inspecting a soldered portion of a component with leads according to claim 2 or 3.