Text preview for : cr04228_112k_1 Problem with Subtype Learning When Used with the Connector Algorithm in R7.0 c2001051 part of
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Agilent | Problem with Subtype Learning When Used With the Connector Algorithm in R7.0
Problem with Subtype Learning When Used With the Connector Algorithm in R7.0
There has been a potential issue identified on the 5DX that occurs when subtype learning is applied to
multi-board panels that are using panel based thresholds. Since software version 6.1, NDF and RTF
threshold files (algo_thr.ndf, algo_thr.rtf) are supported in both board and panel directories. Previously
they were only supported in a board directory (board based thresholds). This change has been made to
make it easier to share thresholds across all boards on multi-board panels, including divided long panels.
Panel based thresholds refer to the case where the threshold files reside in the panel directory.
When subtype learning is applied to multi-board panels that are using panel based thresholds, subtype
learning will always result in a sigma value of zero when performing calculations for thresholds. This
poses no problems for joint types such as BGA2 or FPGULLWING, as this information is only noted in
the comment field in the threshold editor. However, this does present an issue when subtype learning is
applied to the CONNECTOR algorithm family, where the sigma values are used to set various threshold
values in the Open algorithm. The threshold parameters under the Open algorithm that are affected are
MIN_LENGTH, MAX_LENGTH, MIN_HEEL_SLOPE, MIN_TOE_SLOPE, MIN_SLOPE_SUM, and
MIN_SUM_SLOPE_CHGS. Incorrect values in these threshold parameters can result in false and/or
erroneous calls.
Work Around
A work around for this issue is to first perform subtype learning with the CONNECTOR algorithm, then
use Review Measurements to manually set the algorithm thresholds. Additional information on the
Review Measurements utility can be found in the 5DX Reference Guide.
After performing subtype learning, manually enter values for the following threshold parameters:
SPC
NOM_FILLET_THICK Set to nominal value
Open
MIN_LENGTH Set to Average minus 4 Sigma
MAX_LENGTH Set to Average plus 4 Sigma
MIN_HEEL_SLOPE Set to Average minus 4 Sigma
MIN_TOE_SLOPE Set to Average minus 4 Sigma
MIN_SLOPE_SUM Set to Average minus 4 Sigma
MIN_SUM_SLOPE_CHGS Set to Average minus 4 Sigma
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