Six Sigma Tools (Measure)

Question 1

7 Basic Quality Tools

Answer 1

• Provide a structured approach to understanding process variation, identifying its causes, and eliminating the causes
• The tools include: process flow diagrams/value stream maps; checksheets; bar charts/histograms; run chart; pareto analysis; scatter plots; fishbone/cause-and-effect diagrams.

Question 2

Process flow diagrams

Answer 2

• Circle: start and end points
• Square: tasks
• Arrows: flows
• Downward triangle: waits
• Diamond: decision points

Question 3

Value stream mapping (why use it)

Answer 3

• Helps visualize the flow across more than just a single process
• Helps see waste (muda) and sources of waste
• Ties together the principles of lean thinking (avoid “cherry picking”)
• Forms the basis of an implementation plan to help design the whole door to door flow
• Shows the relationship between material and info flow
• provides a common language

Question 4

Value stream mapping (how)

Answer 4

• Select a product family
• Draw current and desired states (Gemba, go back and forth between current and desired states, which could take between 3-6 months).
• Work plan

Question 5

Checksheets

Answer 5

• List problems;
• Count numbers of occurrence

Question 6

Hard savings

Answer 6

• Directly flow to the P &L
• Do the same amount of biz with less employees (cost savings) or handle more biz without adding people (cost avoidance).

Question 7

Soft savings

Answer 7

• Hard to quantify
• Benefits such as reduced time to market, cost avoidance, lost profit avoidance, improved employee morale, enhanced image for the organization and other intangibles.

Question 8

Gage R&R

Answer 8

• A statistical tool that measures the amount of variation in the measurement system arising from the measurement device and people taking the measurement.
• Application: Each employee will measure each item multiple times (repeatability) and their average measurement of each item will be compared to the average for the operators or measurement tools (reproducibility).
• If the variation of repeatability and reproducibility exceeds 10% of the tolerance width (upper limit – lower limit), then it is recommended to make improvements in the measurement system to reduce the variation.

Question 9

Defects

Answer 9

Non-conformance to customer specifications

Question 10

DPMO

Answer 10

• Defects per million opportunities
• DPMO = (No. of defects observed)/ (No. of units produced) * (Number of defect opportunities) * 1, 000,000
• Convert DPMO into a sigma level - A 1.5 sigma shift (“process walk” ) process should be considered in most cases, as short-term measurement is used to predict long-term performance of the process.

Question 11

Urgent/Important Matrix

Answer 11

• Basically a prioritization tool
• Prioritize urgent & important
• Delegate urgent & unimportant
• Schedule non-urgent and important
• Don’t do non-urgent & non important

Question 12

Breakthrough Equation

Answer 12

• Basically, an equation that summarizes six sigma
• The objective is to discover an appropriate level of knowledge regarding the Xs and their deterministic effect on Y so that only a tolerable level of ε risk remains.
• Y is the outcome/results
• X represents the inputs
• f is the function, the way or process by which the inputs are transformed into outputs
• e is the error, or uncertainty surrounding how accurately the Xs are transformed to create the outcome.

Question 13

Takt time

Answer 13

• Takt time is the rate at which a finished product needs to be completed in order to meet customer demand.
• e.g. if a company has a takt time of 5 minutes, that means every 5 minutes a complete product, assembly or machine is produced off the line because on average a customer is buying a finished product every 5 minutes.
• It’s a pull system, try to avoid overproduction
• Takt time = Available time for production per day / Customer demand per day

Question 14

Capability analysis

Answer 14

• Cp
• Cpk
• Whether meet customer specifications.