MAN3506 Inspection
MAN3506
Operations Management
Midterm Exam Notes
Ch. 10
Inspection
Is an appraisal activity that compares goods or services to a standard. Purpose is to provide info to the degree to which items conform to a standard.
Less of an issue for lean organizations because; they place extra emphasis on design
Important for service operations where quality is a continuous issue.
Occurs @ 3 points:
Before Production- make sure units are acceptable (Acceptance sampling)
During Production- conversion of inputs to out puts, Process control
After Production- Final verification continuous Improvements, (Acceptance sampling)
Basic Issues:
How much inspection is needed
Little Inspection: required for low-cost high volume items Pencils, paperclips
Intensive Inspection: high-cost low volume. If item has high volume use automated inspections
The amount of insp needed is governed by the cost of inspection and expected cost of passing defective items.
At what points in process inspection should occur
Raw materials- supplier certification programs reduce need
Finished product
Before a costly inspection
Before an irreversible process
Before a converting process. Ex. Paint, planting, assembling
Whether to inspect on site or centralized location
Whether to inspect attributes (count the # of times something occurs) variables (measure the value of characteristics
Statistical Process Control
Quality of conformance: A product or service conforms to specifications. Does the output of a process conform to the intent of the design
Statistical Process Control- when process output has variations in characteristics, SPC is used to evaluate process output to decide if a process is “in control” or if corrective action is needed
Process Variability- are output variations within an acceptable range
Random Variation- Natural variation in the output of a process created by countless minor factors.
Assignable variation- In process output a variation whose cause can be identified. A non random variation
Sampling & Sampling distributions
Sampling distribution- serves as a theoretical basis for distinguishing btwn random and nonrandom values of a sampling statistic
Process distribution & Sampling distribution: both have the same means, the variability of the sampling distribution is less than the variability of the process distribution, the sampling distribution is normal
Central limit theorem- the distribution of sample averages tends to be normal regardless of the shape of the process distribution.
Control Process:
Define
Measure
Compare
Evaluate
Correct
Monitor results
Control Charts: a time ordered plot of sample statistics used to distinguish between random and nonrandom variability.
Control limits- the dividing lines between random and nonrandom deviations from the mean of the distribution
Type 1 error- concluding a process is not in control when it actually is
Type 2 error- concluding a process is in control when it is not.
Variables- Generate data that are measured
Attributes- generate data that are counted.
Mean control chart- control chart used to monitor the central tendency of a process
P-chart- control chart for attributes used to monitor the proportion of defective items in a process.
Process Capability
Specifications- a range of acceptable values established by engineering design nor customer requirements
Process variations-natural or inherent variability in a process
Process capability- the inherent variability of process output relative to the variation allowed by the design specification
Process Capability
ØThe inherent variability of the process output relative to the variation allowed by the design specification (p.443) (also see Fig 10.15)
Cp = Capability Index
ØCp = Specification Width / Process Width = Upper Specification – Lower Specification/ 6 Sigma
hihi
Want to order fresh copy of the Sample Template Answers? online or do you need the old solutions for Sample Template, contact our customer support or talk to us to get the answers of it.
