创建组件识别数据的方法.pdf - 第176页
176/178 IM-SMT-VSNDI C-0002 -000 A ppendix 4. Lead position check Using the posit ion where the le ad tips should exist (th e black dots at the lead tips in Figur e 147) as the ce nter , it chec ks whether the ce nter of…
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For example, if the brightness is distributed as shown in
Figure 146
along the line being
scanned, the leads can be detected correctly with the difference in detection levels (threshold
A), but with detection level difference B, reaction to the noise can be seen. With detection
level difference C, the leads cannot be detected at all.
Figure 146
Consequently, the largest possible value should be set as the detection level difference
in order not to detect the noise within a range in which there is no error in lead detection.
Normally, a value that is approximately half of the difference between the maximum
luminance and the background luminance is thought to be appropriate.
In a search for the appropriate value, the center value of the range where recognition is
performed successfully is obtained as the set value, while changing the combination of the
illumination level and the detection level difference.
However, as searches for the appropriate value are conducted only on one component,
disparities between components are not taken into consideration.
Appendix 3. Creating simple data in the special recognition modes
Some recognition modes provide modes called “special recognition modes”. These are used
to recognize components that cannot be recognized with the standard settings. In this case, a
special mode is also used for the component data settings.
All of the setting items can be entered in this mode, in other words, it is necessary to set all of
the required setting items manually. In order to minimize the manual work, the data can be
created using the standard procedure described below and then the recognition mode
changed in order to eliminate delays in creating the data.
For example, when the SOP data is created in a normal manner by using the Special 1
algorithm for SOP recognition, the following changes are made:
Alignment Group : Special component ( IC component)
Alignment Type : Special shape ( SOP)
Then the following are set in order to eliminate delays in creating the data:
Algorithm : Special 1
Base Alignment Type : SOP
The data for the lead length, Lead Width, Lead Pitch and reference lead position (Find Pos)
can be created automatically by entering the data as usual.
After that, the data set automatically is retained just as it is, and the correction is required to
be made only for the necessary items.
Detection level difference C
Detection level difference A
Detection level difference B
Background intensity
Brightness distribution on the scan line
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Appendix 4. Lead position check
Using the position where the lead tips should exist (the black dots at the lead tips in Figure
147) as the center, it checks whether the center of the actually detected lead tip is in the
allowable range or not.
In other words, this checks the offset between the actual lead tip position and the ideal
position that was determined from the component data, the component center that was
determined, and the tilt.
If the check range is 1.0 mm, this checks to see if the detected lead is within a range of +-1.0
mm.
Figure 147
Allowable range
Allowable range
Allowable range where the
lead
tip should be as its center
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Appendix 5. Reading and interpreting the recognition results display
The recognition results are displayed on the vision monitor or in the vision image monitor
window. The displayed contents vary depending on the recognition mode.
This section describes the typical results.
<For lead components>
Figure 148
Component detection center coordinate (
critical area
)
The total number of det
ected leads
Tilt of detected
component.
(degree)
Coordinate for the
center of
the side.
(pixels)
Number of the
leads per side.
Average pitch
per side.(mm)
Average lead width
per side. (mm)
The lead whose
ｔ
ip is detected
Lead detection lines
Lines connecting the
center position on the sides