Name and describe the main families/typologies of control charts
(p. 155)
For variables
Quality characteristics measured on a continuous numerical scale
For attributes
Quality characteristics assuming only two, binary states:
defective/non-defective
conforming/non-conforming
go/no-go
good/bad
Describe the characteristics of a control chart for attributes
(p. 156)
Many quality characteristics are not measured on a continuous or quantitative scale
Each unit of product is judged as conforming or non-conforming (defective), on the basis of certain attributes.
Compare control chart for attributes and variables
Charts for attributes are less expensive
because measurements are less complex to be performed.
Attributes charts are generally not as informative as variables charts (lower information content).
Sample size is typically larger => at least n ≥ 20 to 25
What is used to determine the conformance to specifications of manufactured parts
(p. 157)
Hard Gauges => Go / No-Go-Test
Definition of
Defect
Defective
(p. 164)
Defect => Auftreten einer spezifischen Nichtkonformität, die so schwerwiegend ist, dass sie die sichere oder wirksame Verwendung des Produkts erheblich beeinträchtigt.
Defective => Product unit with one or more defects.
Name the different control charts for attributes and their purposes
(p. 165)
For defectives
(p) control chart for fraction nonconforming
(np) control chart for number nonconforming
For defects
(c) control charts for defects/ nonconformities
for every product unit, we count the No. of defects on it.
(u) control charts for defects/nonconformities per unit.
Last changed9 months ago