OM 22: Quality Control Flashcards
Acceptance Sampling and Process Control
Acceptance Sampling: Sampling before or after production
Process: Monitoring during process
Where might inspection make sense?
- Raw Materials
- Work in Process
- Finished Goods
- Before costly operation
Control Chart Definition
Time-ordered plot os sample statistics used to distinguish between random variability and nonrandom variability
- To monitor process outputs to see if it is random
Type I Error
Concluding the process is not in control when it actually is
- Producer’s Risk
Type II Error
Concluding process is in control when it is not
- Consumer’s Risk
Process Capability tells you…
if the process can reliably produce good output
Process Capability Analysis is conducted by comparing…
- Natural/ inherent process variability (sigma)
- range of acceptable values (upper and lower specifications)
How to know if process is capable
If process capability ratio is greater than 1.33
Statistical Process Control SPC
Once it is determined that the process is capable, make sure to keep it in control
- SPC evaluates to determine if the process is in control and if corrective action is needed
Control Chart for Variable measures
- length/ width of a part
- amount of time to complete a task
Mean Control Chart vs Range control chart
- Mean measures central tendency
- Range measures dispersion
