In general terms, how does the algorithm work? The algorithm uses image processing to determine the center point of each lead on a per lead group basis. It then performs a best fit for each lead group by using the programmed model data for that given lead group only.

1. 1
SM Platform Product Team
Best Practices
51030001, Rev. C
Leaded Application Notes
What are some of the common classes of leaded packages?
Descriptions Views
Small Outline Transistor (SOT) - A
plastic leaded component in which transistors are
packaged.
Plastic Leaded Chip Carrier (PLCC) -
Normally a four-sided quad package in which an IC
is installed with J-type leads extending out from the
sides of the package then down and rolled under the
body of the device.
Small Outlined Integrated Circuit
(SOIC) – A small dual in-line package that has
gull-wing shaped leads.
Thin Small Outline Package (TSOP) -
Similar to SOIC but smaller packaging and closer
lead spacing (8 to 24 leads) with leads protruding
from the ends of the package.
Quad Flat Pack (QFP) - Four-sided device
normally with extended gull-wing leads.

2. 2
In general terms, how does the algorithm work?
The algorithm uses image processing to determine the center point of each lead
on a per lead group basis. It then performs a best fit for each lead group by
using the programmed model data for that given lead group only.
Where is the lead type configured? How many different lead
types are there?
The Lead Type is found on the Leads tab of the component definition.
Currently, there are five lead choices:
1. Gull Wing
2. J Bend
3. UIC A
4. UIC B
5. UIC C
Assigned center points
using high speed or
standard accuracy.
Finally, the component location is generated by
using the center points from all of the lead
groups.

3. 3
Lead Type Description Examples
Gull Wing: Finds lead tips and is
commonly used for gull-wing
component types (QFP, SOIC, etc.).
J Bend: Finds lead centers and is
commonly used for J-type components
(PLCC, SOJ, etc.).
One Lead: This lead type is optimized
for components with one lead per lead
group, such as e-caps and crystal
oscillators.
E-Cap
UIC A: Finds lead tips and is typically
used for components whose leads
have non-uniform reflectivity. This lead
type is also more geometrically tolerant
than the gull-wing lead type (i.e. more
tolerant to slightly bent leads).
UIC B: The same as UIC-A except this
algorithm finds the inside tips and is
also known as "inverted lead find".
Crystal

4. 4
Lead Type Description Examples
UIC C: Finds lead tips, but used for
components with very large leads that
take up more than 25 pixels in width on
the camera.
Large Leads
How do I convert my lead dimensions into pixels?
Divide each lead dimension (in global units) by the camera resolution (in global
units per pixel).
For example, say we have the following data:
• Camera resolution = 2 mils/pixel
• Lead width = 14 mils
• Lead length = 24 mils
Lead width = 14 mils / 2 mils/pixel = 7 pixels
Lead length = 24 mils / 2 mils/pixel = 12 pixels
NOTE: 1 mil = 1 thousandth (10-3
) of an inch
What does Inspection Type mean?
The Inspection Type is found on the Vision tab of the component definition.
There are two choices:
High Accuracy
High Speed
From the perspective of the
leaded algorithm, the
Inspection Type determines
if additional image
processing is used to center
the component.
The image on page 2
corresponds to High Speed.

5. 5
The image below depicts High Accuracy centering. With High Accuracy
centering, the algorithm will revise the center points by using grayscale rulers for
each lead on a per lead group basis.
What are the advantages and disadvantages to high accuracy?
Advantages:
• More accurate placements
• Sometimes can be used to find leads that were labeled as missing with
High Speed
Disadvantages:
• Slower, particularly on the 630 and older vision systems
When should High Accuracy be used?
High Accuracy processing is generally used for fine pitch components that are
configured for lead inspection.
When should lead inspection be used?
Lead inspection is typically used with fine pitch components where an extra level
of checking is required to ensure that the leads are not bent or otherwise
damaged. It is typically not used for robust course pitch components that are
packaged and handled in such a way to preclude lead damage.
New center points using
high accuracy.

6. 6
Where is lead inspection configured?
Lead inspection is configured in the Vision tab of the component definition.
What are the prerequisites for using lead inspection?
An accurate model of the component is crucial for reliable lead inspection. The
component definition is the benchmark to which the image is compared. It must
accurately describe the component as imaged by the chosen camera.
Common component programming errors include inaccuracies in the following:
• Body size
• Lead length/pitch
• Component thickness - Thickness is important since varying heights lead to
geometrical distortions when imaged with non-telecentric optics (e.g. FlexJet,
HSC WFOV). Consult with your sales representative for other cameras not
mentioned.
Descriptions of Lead Inspection Parameters
Parameter Description Graphic
Lead Tolerance From Body
The maximum distance away from the expected
position from the body, the leads maybe found.
Lead Tolerance Across Body
The maximum distance away from the expected
position across the body, the leads maybe
found.
Lead Spacing Tolerance
The maximum distance the leads maybe bent
from side to side. Pitch inspection.

7. 7
Lead Len Positive Tolerance
The maximum amount the leads may be longer
than expected.
Lead Len Negative Tolerance
The maximum amount the leads may be shorter
than expected.
NOTE: When a tolerance inspection is performed, the actual lead is compared to
the average lead parameter for that side of the component. If the difference is
greater than the tolerance value entered, the component is rejected.
Setting up Lead Inspection Parameters
NOTE: When using lead inspection, it is recommended that the Centering Type
be set to High Accuracy in the Vision tab of the component definition.
1. Create an accurate component definition of the leaded device. Use a supplier
specification sheet if provided.
2. Gather a collection of components that would be considered defective from a
lead quality perspective.
3. Run one of these components in Enhanced Component Setup (ECS) from the
definition generated in Step 1.
4. Select the Inspect checkbox in the Lead Inspection frame in the Vision tab of
the component definition.
5. Based on the typical lead defects found on the component, use the table
above to choose lead inspection parameters that will discriminate against the
defects.
6. Values entered in the lead inspection fields are +/-. For example, if .006” is
entered, it would equate to +/- .006”
7. A value of zero indicates that particular lead inspection parameter is
bypassed.
Example:
8. Choose one lead inspection option and enter a tolerance.
This component has leads that
are bent down and not side-to-
side. Good choices for lead
inspection parameters include:
• Lead Tolerance From Body
• Lead Len Positive Tolerance
• Lead Len Negative Tolerance

8. 8
9. Inspect the component in ECS and note the displayed MAX DEVIATION.
This is the deviation of the chosen inspection observed by the vision system
(units are in microns). Since this is a part that should fail lead inspection,
adjust the corresponding tolerance to be smaller than the MAX_DEVIATION.
Record the tolerance.
10.Repeat this process for each of the chosen lead inspection parameters
separately.
11.When finished, re-enter all of the tolerances determined in Steps 6-7 and test
the component definition with other “bad” components as well as “good”
components.
12.Refine the tolerances as necessary to ensure that the definition passes high
quality components and fails components with unacceptable lead damage.
NOTE: Lead inspections are performed sequentially in the order listed in the
component database. If an early inspection fails, no further inspections are
performed.
Are there any alternate methods for setting up lead inspection?
Yes, the lead inspection parameters can also be setup based on pad size and
required coverage.

9. 9
What are some of the potential problems with the leaded
algorithm?
Component skews
Corner glints or features could be misinterpreted as leads leading to
component skews.
Solutions:
1. Verify the accuracy of the component description
2. Adjust light level and/or type (sometimes less is more)
3. Use noise filter, as demonstrated below
4. Use high accuracy
5. Use lead inspection
Example1:

10. 10
Possible Solution:
For UPS+ 6.2 or higher, check the Noise Filter box on the Vision tab of the
component definition.
Selecting the Noise Filter checkbox filters out lead-like artifacts that
appear to the sides of true leads or near the ends of true lead groups.
This option improves the processing of components with diagonal leads or
features. The Noise Filter option requires a geometrically accurate
definition and is generally only recommended for devices that have non-
lead features such as corner markings.

11. 11
Example 2:
Possible Solution:
Check the Noise Filter box on the Vision tab of the component definition.

12. 12
Troubleshooting Tips for Component Failures
Always start your investigation by verifying the accuracy of the component
description. This can be done through Enhanced Component Setup (ECS)
from within the component definition. For more information on how to use this
tool, refer to the online Help system.
This component description is
incorrect, the lead pitch and
component dimensions (length
& width) need adjusting.
This component description is
correct.

13. 13
Next, after verifying the accuracy of the component description, adjust the
lighting to illuminate the lead surface evenly. However, be careful not to
illuminate the background too much.
Does the entire lead need to be illuminated?
No, it’s recommended that only the programmed portion (i.e. the foot) of the
lead be illuminated.
J Bend:
Gull Wing J Bend
This lead is under illuminated.
Notice that the foot is not evenly
illuminated, which could result in
missing leads or placement issues.
Adjust the light level and/or light type.
This lead is ideally illuminated.
Notice that the foot is evenly
illuminated without excessively
illuminating the other parts of the
lead.

14. 14
Gull Wing:
NOTE: On-Axis lighting is recommended for palladium leads.
This lead is over illuminated.
Notice that the entire lead is over
illuminated, which could result in
missing leads or placement issues.
Adjust the light level and/or light
type.
This lead is under illuminated.
Notice that the foot is not illuminated,
which could result in missing leads or
placement issues. Adjust the light level
and/or light type.
This lead is ideally illuminated.
Notice that the foot is evenly
illuminated without excessively
illuminating the other parts of the lead.
This lead is over illuminated.
Notice that the entire lead is over
illuminated, which could result in
missing leads or placement issues.
Adjust the light level and/or light type.

15. 15
Why does my component fail in production, but pass in ECS?
This problem could be due to a mismatch in the feeder entries. Make sure
the same feeder is being used in both places.
For ESC, the feeder information is retrieved from the component description.
However, for production the feeder information is retrieved from the product.

16. 16
Another potential problem is with the inspection angle. Depending on the
lead finish and camera type, some leads illuminate better in one orientation
than another.
Check for this problem by inspecting the component in both orientations
within ECS.
Try the following suggestions to avoid this problem.
• Adjust lighting
• Turn off pre-orient
• Use a different camera type, preferably one with true on-axis lighting (e.g.
the Magellan ULC)
Change the
Inspect Angle to
rotate the
component.
NOTE: The
component must
be repicked for
the new inspect
angle to take
effect.