Effect of reducing variation in a product
more consistency and higher quality
How control charts' upper and lower control limits are determined
by the natural variation in the process
How process capability's upper and lower control limits are determined
by customer specifications
Fact about binding constraints
each has a shadow price
Types of Quality Tools
Fishbone diagrams, flowcharts, histograms, process capability, check sheets, Pareto charts, scatter plots, line charts, control charts, and run charts
Appraisal costs
Costs of activities designed to ensure quality or uncover defects
Prevention costs
All TQ training, TQ planning, customer assessment, process control, and quality improvement costs to prevent defects from occurring
Internal failure costs
Costs incurred to fix problems that are detected before the product/service is delivered to the customer
External failure costs
All costs incurred to fix problems that are detected after the product/service is delivered to the customer
X bar chart
Mean control charts; used to monitor a process' central tendency
R chart
Range control charts; used to monitor the process dispersion
How to Interpret a Range Chart
If the points are all inside the limit, the process is in control.
P chart
Control chart used to monitor the proportion of defectives in a process
C chart
Control chart used to monitor the number of defects per unit
Fact about stable processes
Even if their process control charts say they are in control they can still be incapable.
Quality Assurance Phases
Acceptance Sampling, Process Control, and Continuous Improvement
Acceptance Sampling
Inspection of lots before/after production
Process Control
Inspection and corrective action during production
Continuous Improvement
Quality built into the process
Flowchart process step
Rectangle
Plan-Do-Check-Act Cycle's inventor
W. Edwards Deming
What to do if a process is not capable
Reduce variation
What to do if a process' CP is capable but its CPK isn't
Center the process
Best Process Indicator for capability
CP because it indicates whether the process is capable
Pareto Effect; important few and trivial many concept
Only a critical few inputs have a significant impact on output; concentrate on those; 20-80 effect
Process improvement
A systematic approach to improving a process
Process improvement's goals
increasing customer satisfaction, achieving higher quality, reducing waste, reducing costs, increasing productivity, and reducing processing time
Transportation model assumptions
The items to be shipped are homogeneous, shipping cost per unit is the same regardless of the number of units shipped, and there is only one route or mode of transportation being used between each origin and destination
Cost to ship a part from Factory 1 to Customer A
Cost to ship a part from Factory 2 to Customer B
Numbers in the corner boxes in the transportation problem
Costs
Transportation Problem Supply Constraints
Transportation Problem Demand Constraints
Transportation Problem: type of problem that uses minimization
Cost Problem
Transportation Problem: How to write the objective function for one line
Start by writing "Min." Write the costs in front of the X's, write the factory number as the first digit in the X's subscript, write the warehouse letter as the second digit in the X's subscript, and separate the variables with plus signs.
Transportation Problem: How to write the objective function for the entire grid
Start by writing "Min." Separate each line with a plus sign, either written before or after the line.
Allowable increase
amount to which the objective coefficient in question could increase and the decision variables will still be optimal