IPC9850_Surface Mount Equipment Characterization.pdf - 第38页
IPC-9850 Official Proposal May 2001 38 CMM Capability to Evaluate Metric Parameters IPC-9850-F3 Machine Axis Repeatability & Reproducibility, GR&R Limits 1 Accuracy, Spec. Limits 1 Date of GR&R Study ________…
IPC-9850
Official Proposal
May 2001
37
Reliability Performance Form
IPC-9850-F2
Attribute defect rate and Reliability numbers are not to be construed as guarantees in any way. They simply indicate
actual levels of reliability for this equipment achieved at customer locations.
Manufacturer Name
Machine Model
Attribute Defect Rate (ppm)
Specified Components Alternate Components Used
Component
Type
Quantity Component
Type
Quantity
SOT-23 440
SOIC-8 440
1608C 880
1608R 880
1005C 880
1005R 880
Mean Placements Between Assists (MPBA)
Mean Time To Recover from assists (MTTR
a
), minutes
Mean Placements Between Failures (MPBF)
Mean Time To Repair failures (MTTR
f
), hours
Equipment Dependent Uptime, %
Amount of Preventative Maintenance per 6000 Hours, hours
Mispick Rate (ppm)
Data Collected From:
Number of Factories
Number of Machines
Total Number of Placements
Form 9850-F2 Reliability, issue date
IPC-9850
Official Proposal
May 2001
38
CMM Capability to Evaluate Metric Parameters
IPC-9850-F3
Machine
Axis
Repeatability & Reproducibility,
GR&R Limits
1
Accuracy, Spec. Limits
1
Date of GR&R Study
__________
Glass
Slugs
2
1608 Cap SOIC-16
Glass
Slugs
2
1608
Cap
SOIC-16
X,
micrometers
Y,
micrometers
Placement Verification
Glass Panel
θ, deg
X,
micrometers
Y,
micrometers
Measurement Capability
Glass Panel
θ, deg
Note 1: To be valid, reported Spec. Limits in form IPC-9850-F1 must not exceed worse case Spec. Limits of the CMM
capability per component type.
Note 2: Since the CMM utilizes the fiducial markings on all glass slugs, regardless of the specific component image, it is only
necessary to evaluate the CMM’s ability to measure the slugs using the fiducial markings.
Form 9850-F3 CMM Capability, issue date
IPC-9850
Official Proposal
May 2001
39
Appendix A: Capability Indexes.
Cp can be computed when a process specification limit is stated:
s
6
SpecLimitLower imitUpperSpecL
⋅
−
=Cp
For a process with target of zero, the upper and lower specs have the same magnitude, the equation can be rewritten
as:
s
3
imitUpperSpecL
⋅
=Cp
Cpk quantifies how many sets of 3 standard deviations lie (fit) between the process mean and the closest
specification limit. Cpk is intended for use with distributions that are normal or near normal, and is valuable because
it can be used to quantify the number of placements per million that will occur outside of the specification limits due
to the lack of accuracy or repeatability of the placement machine.
(
)
Cpk
min x Lower Spec Limit , Upper Spec Limit x
3 s
Distance between the mean and the nearest spec
3 s
=
− −
⋅
=
⋅
where s = the standard deviation of the sample.
-4
-
3.
75
-
3.
-
3.
25
-3
-
2.
75
-
2.
-
2.
25
-2
-
1.
75
-
1.
-
1.
25
-1
-
0.
75
-
0.
-
0.
25
-
1.
42
1E
-
0.
25
0.
5
0.
75
1
1.
25
1.
5
1.
75
2
2.
25
2.
5
2.
75
3
3.
25
3.
5
3.
75
4
Mean
LSL
USL
Cpk Numerator
Cpk Denominator
Figure A-1, title
For a centered process the Specification Limits (SL) are obtained by using the following equation, where SD is the
standard deviation and Avg is the average of the data set.