IPC-TM-650 EN 2022 试验方法1.pdf - 第36页

Comparisons to S peciﬁcations (Used when both speciﬁcations exist) T o pic Equation Calculation Answer Comparisons to T otal V ariation T o pic Equation Calculation Answer Measurement T olerance T o pic Equation Calculat…

Measurement Precision Study – Calculation Sheet

Sample Data

Sample 1 2 3 4 5 6 7 8 9 10

Average Part

Average

Condition Data

Condition A B C D E F G H I J

Average

Condition

Range

Variability Calculations

Topic Equation Calculation Answer

K Factors

Readings K1

Parts K3Operations K2

IPC-TM-650

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Comparisons to Speciﬁcations (Used when both speciﬁcations exist)

Topic Equation Calculation Answer

Comparisons to Total Variation

Topic Equation Calculation Answer

Measurement Tolerance

Topic Equation Calculation Answer

IPC-TM-650

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(IPC Measurement Precision Task Group (7-11a), Version 1.0)

Welcome 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-1.9.

This software is useful in cases where the measurement data is recorded as variables data and recorded on a continuous

scale. The calculations allow for up to ﬁve repeated readings, taken on each of up to 10 samples by up to 10 test laborato-

ries or test conditions.

Please refer to the test method before beginning the study. The test method deﬁnes the terms and equations used in detail.

This User Guide provides detailed instructions for analyzing the MSA data on the Measurement Precision Calculator, and

how to draw conclusions from the metrics.

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

• Further information on the K factors used in the calculations

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 test 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.

Begin by determining the measurement processes to be evaluated. All measurements are candidates for a study. In every

case where we perform a measurement, we deserve to know the precision of the measurement. Every measurement could

be followed by a ‘‘± X’’, where ‘‘X’’ would represent the tolerance of the measurement.

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 measurements 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 com-

binations 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 they begin with the most critical ﬁrst.

So, the second step in preparing the MSA is to prioritize the candidates. The best ranking method for one’s situation will

probably be unique, but there are several factors to consider.