IPC-TM-650 EN 2022 试验方法.pdf - 第24页
T able 5: Measurement System Scorecard Results T ester 123456789 1 0 T otal Disposed correctly Good and rejected Bad and accepted Total tests Acceptable parts Rejectable parts # of testers Number of testers times the num…
T
able 3: Good Parts That Were Rejected
Score a ‘‘1’’ where good parts were rejected in Table 1 above.
Score a ‘‘0’’ everywhere else.
Note the scores for each tester in the table below.
T
ester
Samples
12345678910Total
True
Standard
1
2
3
4
5
6
7
8
9
10
Table 4: Bad Parts That Were Accepted
Score a ‘‘1’’ where bad parts were accepted in Table 1 above.
Score a ‘‘0’’ everywhere else.
T
ester
Samples
12345678910Total
True
Standard
1
2
3
4
5
6
7
8
9
10
IPC-TM-650
Number
1.8
Subject
Measurement
Precision Estimation for Binary Data
Date
01/03
Revision
A
P
age5of6
T
able 5: Measurement System Scorecard
Results
T
ester
12345678910Total
Disposed
correctly
Good
and
rejected
Bad and
accepted
Total
tests
Acceptable parts
Rejectable parts
# of testers
Number
of testers times the number of parts.
Count acceptable parts in the True Standard line of the data input table.
Count rejectable parts in the True Standard line of the data input table.
Count the number of participants.
T
able 6: Measurement System Effectiveness
Metric
Calculation Result Acceptable
Needs
Improvement
T
est effectiveness (%)
Total parts dispositioned correctly
Total
parts tested
x 100
>90 <80
Probability of false rejects (%)
Total good and rejected parts
(No.
of testers) x (Good parts)
x 100
<5 >10
Probability of false acceptance (%)
Total bad and accepted parts
(No.
of testers} x (Bad parts)
x 100
<2 >5
IPC-TM-650
Number
1.8
Subject
Measurement
Precision Estimation for Binary Data
Date
01/03
Revision
A
P
age6of6
Measurement
Precision Calculator Users Guide
For
Use with Test Method 1.8,
Measurement Systems Analysis for Binary Data
(IPC
Measurement Precision Task Group (7-11a), Version 1.0)
Introduction
W
elcome to the Measurement Precision Calculator. This utility will help perform the calculations for Measurement Systems
Analysis (MSA) described in the IPC Test Method IPC-TM-1.8.
This software is useful in cases where the test or inspection results are recorded as binary data, resulting in one of two out-
comes, such as pass/fail or go/no-go. The calculations allow for results on up to 10 samples by up to 10 test conditions or
test laboratories.
Please refer to the test method before beginning the study. The test method defines the terms and equations used. This User
Guide provides instructions for analyzing the MSA data on the Measurement Precision Calculator, and how to draw conclu-
sions.
This software is an Excel workbook and includes the following:
• A blank spreadsheet to enter measurements
• A spreadsheet with example data
• A form for manual data entry, if desired.
The goal in preparing this workbook was to keep it as simple and easy to implement as possible, but still provide a good
basic MSA. This procedure has been used many times and can often be completed with as little as an hour’s work on each
of three consecutive days. This method provides a good initial assessment. It is quick and easy enough to be used on all
tests, current and new. It can help isolate cases where further analysis is needed. It is useful both on current production tests
and as a validation review for new designs.
This spreadsheet has been tested with the Excel versions included with Office 97 and Office 2000. It does not use macros,
so compatibility problems have been minimized. The sheets were formatted to print on 8-1/2 by 11 pages on most laser and
ink jet printers.
Preparing
for the study
Begin
by determining the measurement processes to be evaluated. All inspections are candidates for a study. In every case
where one performs a test or inspection, one deserves to know its effectiveness. What portion of the bad units will one miss?
What portion of the failed units will be good?
The secret to performing a good MSA is to prepare well. The first step in preparing the MSA is to identify all the MSA
candidates. Begin by identifying the inspections being performed. List the equipment needed, the parts tested, and the set-
ups required. For each piece of equipment, note the ranges used. The complete list of MSA candidates includes all combi-
nations of all tests, equipment, set-ups, ranges and all products.
As in many cases, this list probably includes far more potential candidates for an MSA than time or budget restrictions will
allow. So one must identify the top candidates and make sure the MSA begins with the most critical first.
The second step in preparing an MSA is to prioritize the candidates. The best ranking method for one’s situation will prob-
ably be unique, but there are several factors to consider.
January
2003 Users Guide
1