统计过程控制-测量系统分析

Basic concept of SPC

Ppk Ca Cp Cpk
Basic concept of SPC



Ca : Sensitive to Specification target Cp : Sensitive to variation(spread) Cpk : Sensitive to both, capability index for stable process Only common cause variation included Ppk : Performance index Both common cause and special cause variation included Cp ≦Cpk
Data Categories & Resolution
Data Categories & Resolution
Data Categories & Resolution
Data Categories & Resolution
Data Categories & Resolution
Data Categories & Resolution
Cp is good, not use for process measurement, C/I not required?

只做GRR,不做Bias, Linearity, Stability 可以吗?
MSA for measurement can’t be repeated




The inability to test the same unit repeatedly is a major obstacle to obtaining an estimate of pure measurement error. Destructive testing Measuring a temperature, viscosity Samples obtained from the product stream should be as closed together as possible With film, one might prefer adjacent samples collected in the machine direction rather than from different positions across the web Obtain pairs of samples that are as homogeneous as possible within each pair, each pair may be tested and the difference in the paired readings taken to obtain an estimate of the variation of the measurement process
数加权移勋平均管制图

EVOP(Evolutionary Operation)-Part Average Test渐进操作法管制图 Acceptance Control Chart允收管制图 Modified Control Limits Control Chart修正界限管制图 Short Run短制程管制图
SPC

Statistic Process Control
Statistic technique Proces s Control
SPC
由Product Spec到Process Parameter
由Product Spec到Process Parameter
1.
Basic concept of SPC

MSA Result
Gage resolution to spec tolerance Gage resolution to Process variation Bias Stability Linearity R&R

When should MSA be conducted in APQP/Product Realization/Product Life cycle
1.33
Z
Basic concept of SPC
用管制图判别special cause的准 则 超过管制界限 连续七点向上 连续七点向下 连续七点向单边 不随机分布

Basic concept of SPC

Statistical stable = no special cause = Under control = process performance can be predictable

AV2
GRR-Range Method
GRR-Average-Range Method
ANOVA Method
MSA timing & application
MSA / APQP/ Product Realization MSA / FMEA

MSA的目的


何种情况可不必做GRR ?
Data Categories & Resolution
Data Categories & Resolution
PT Ratio
Precision Tolerance Ratio The ratio of parameter tolerance to measurement system repeatability PT=Tolerance /EV
当制程达到Statistical stable时才可计算Cpk
Stable Process
Unstable Process
Basic concept of SPC

Over-adjustment :当对common cause所 造成的变异都采取措施调整制程时,等于 将一个special cause加入己稳定的制程。 使原本稳定的制程变成不稳定。
90% 95%
P 10%
5% 1%
信赖区间
± 1.645σ ± 1.96σ
Ppk/Cpk
0.548 0.653 0.858
99%
± 2.575σ
99.73%
99.94% 99.99%
0.27%
0.06% 100ppm
± 3σ
± 3.5σ ± 3.9σ
1
1.167 1.3
99.994%
60ppm
± 3.99σ

Cpm
管制图种类包括
计量值管制图 计数值管制图
Data的种类
计量值(location
& spread)
计数值
计量值管制图
X-Bar
R Chart X-median R Chart X-Bar S Chart X-Rm Chart
计数值管制图种类包括
P
Variation Control (Stability)-Statistical stable status-Process

performance can be predictable
Capability Over-adjustment

SPC -品管七大手法






Histogram Check Sheet Pareto Cause and effect diagram Defect concentration diagram Scatter diagram Control chart
Bias
Stability
Linearity
Repeatability
Reproducibility
GRR-Average-Range Method
%GRR = % R&R = 100(R&R/TV) TV2 = R&R2 + PV2 2 2 2 2 TV R&R = EV + AV EV2eview Process design review Product/Process Change Periodic review against the ever improved process

MSA scope
Resolution
Bias
location 可重复量测
Pn C U
管制图的目的
预防不良品产出 判定制程是否有非机遇 因子造成的变异 去除非机遇因子造成的 变异 减小制程的变异 改善制程 判定制程是否稳定 制程能力分析 100%检验还需耍做管制 图吗? 如何做?

特殊应用管制图

CUSUMcumulative-Sum Control Chart)累积和管制图 EWMAexponentially Weighted Moving Average Control Chart)指
Basic concept of SPC
Variation :制程输出不可 避免的差异 Inherent Variation (固有 变异):由common cause 所造成的变异 σ= R bar / d2 Total Variation :由 common cause and special cause所造成的 变异 Ppk Cpk
Basic concept of SPC
检定是否为常态分配 管制图的中心线X-bar 管制图的管制界限(信赖水平,信赖区间) Control Limits =信赖区间

1.集中趋势（通常以X bar作代表） 2.离中趋势（通常以σ 作代表） 3.信赖水平-被含盖在特定范围内的机率
信赖水平-被含盖在特定范围内的机率
X bar X bar
信赖水平,信赖区间
信赖水平

信赖区间 ± 1.645σ ± 1.96σ ± 2.575σ ± 3σ ± 3.5σ ± 3.9σ ± 3.99σ


90% 95% 99% 99.73% 99.94% 99.99% 99.994%
信赖水平,信赖区间,P, Ppk/Cpk
信赖水平
MSA

计量值
Location - Bias, Linearity, Stability Spread – Repeatability, Reproducibility(GRR) Range Method Average Range Method Average Range Method(Within Part Variation) ANOVA DOE 计数值-Short Method -Long Method
Specification Tolerance
Stability
Linearity
Variable
R&R Attribute
不可重复量 测
Process Variation
Destructive Testing
Short Run短制程管制图
Guard Band Limit-GRR
Guard Band Limit-Cpk
MSA

Measurement System Analysis
Statistic technique MS Control
MSA
MSA
GRR
v. s.
CP
Accuracy & Precision