chapter 20 Flashcards
2 aspects of quality
- Product features
2. Freedom from deficiencies
What is statistical quality control
where inferences are made about the quality of a population of manufactured items based on a sample taken from the population
2 statistical sampling methods in quality control
- Control Charts
2. acceptance sampling
What is a control chart
a graphical technique in which stats on one or more part or product characteristics of interest plotted over time to determine if its behaving normal or abnormal
what is acceptance sampling
a stat technique in which a sample drawn from a batch of parts its inspected, and a decision is made whether to reject or accept batch based on quality of sample
uses of acceptance sampling
- Verifying quality of raw materials from vendors
- deciding whether or not to ship a batch of parts
- inspecting parts between manufacturing steps in a sequence
management principles and practices pg.20.2.1
d
what are three main objectives of total quality management
- achieving customer satisfaction
- continuously improving
- involving the entire work force
page 20.2.2
factors of modern view of QM
Modern technologies in quality control include
- quality engineering
- quality function deployment
- 100%automated inspection
- on-line inspection
- coordinate measurement machines for dimensional measurement
- non contactsensors such as machine vision for inspection
Process variations divided into 2 types
- random
2. assignable
wide vs narrow tolernces
s
overall objectives of SPC
- improve quality of process output
- reduce process variability and achieve process stability
- solve processing problems
7 methods and tools used in SPC
- control charts
- histograms
- pareto charts
- check sheets
- defect concentration diagrams
- scatter diagrams
- cause-and-effect diagrams
parts of control charts
CL
LCL
UCL
2 types of control charts
- control charts for variables
2. control charts for attributes
a process out of statistical control manifest this condition in changes in
- process mean
2. process variability
2 types of control charts for variables
- x chart
2. R chart
2 types of control charts for attributes
- the p chart
2. the c chart
what features visible on histogram
- shape of distribution
- any central tendency of distribution
- approximations of the means and mode
- amount of scatter in data
Paerto’s law
the vital few and the trivial many
the 80-20 rule
5 elements of
20.4
goals of six sigma
1.better customer satisfaction
2.higher quality products and services
3.reduced defects
continuous improvement
6.cost reduction
DMAIC
d
