Six Sigma Tools (Control) Flashcards
1
Q
Balanced Score Card
A
- A set of measures that gives top managers a fast but comprehensive view of the business
- The balanced scorecard allows managers to look at the biz from 4 important perspectives:
- Customer perspective: How do customers see us?
- Internal perspective: What must we excel at?
- Innovation & Learning perspective: Can we continue to improve and create value
- Financial perspective: How do we look to shareholders?
- The balanced scorecard also forces managers to focus on the handful of measures that are most critical
2
Q
Dashboard
A
- A tool used for collecting and reporting information about vital customer requirements and/or your business’ performance for key customers.
- Provide a quick summary of the process and product performance.
3
Q
Andon
A
- A Japanese word for lantern
- The board hangs over the aisle between production lines and alerts supervisors to any problem
- A typical tool to apply the Jidoka principle in Lean production
4
Q
Deming on the variation in a process
A
- Variation is inevitable in industrial life
- Productivity and quality are linked, not traded off against one another
- Reduce 6Ms
- Common cause variation
- Special cause variation
5
Q
Common cause variation
A
- Systemic issues, shared by numerous operators, machines, or products
6
Q
Special cause variation
A
- Produce non-random variation in the system, usually confined to individual employees or activities
- Causes can be identified and eliminated.
7
Q
Quality
A
- A process needs to be capable and in control to consistently produce to customer requirement
8
Q
Capability
A
- The ability of a product, process, person or organisation to perform its specified purpose based on tested, qualified or historical performance, to achieve measurable results that satisfy established requirements or specification.
- Cp and Cpk are computing a single value to determine whether a process is capable.
9
Q
Cp
A
- Compares the “natural tolerance” of the process (its natural variation) to the specifications: Cp = (engineering tolerance)/(natural tolerance) = (customer specification range)/ 6 sigma
- A Cp of 1 denotes a capable process at 3 sigma - but to allow for drift, a 1.33 is often used as the acceptable minimum (i.e. 4 sigma)
- The disadvantage of Cp is that it doesn’t account for process centering.
10
Q
Cpk
A
- Compares the “natural tolerance” of the process (its natural variation) to the specifications for process centering: - Cpk = Z min - Zu = (upper specification - mean)/3 sigma - Zl = (mean -lower specification)/ 3 sigma
- We look at the difference between the mean and the upper and lower specifications. In a centered process, we’d expect these to be equal.
- At 3 sigma a Cpk > 1 is required (but +1.33 is preferred).
11
Q
Capable Processes in Control
A
- When a process is capable, it can produce output that meets customer specifications.
- However, a process is only in control when it behaves as expected, that is it exhibits only random variation.
- When a process is capable and in control, the process is producing output that meets customer specifications, consistently.
12
Q
Two criteria for capable and in control
A
- Is the process capable, that is does the output meet customer specifications? (calculate Cpk)
- Is the process in control, that is do the outputs meet customer specifications consistently? (variable: x bar and R charts; attribute: p-chart). (only when a process is in control can you know its true capability)
13
Q
How do you identify whether a process is in or out of control?
A
Look at the control chart: if in control, the pattern should be random.
14
Q
Attribute data (e.g. good or defective)
A
- Data that count items, such as the number of defective items in a sample
- Need just one chart, because mean determines standard deviation - p chart. - e.g. “good” or “defective”
15
Q
Variable data (measurement)
A
- Data that measure a particular product characteristics such as length or width.
- Need two charts because mean and standard deviation are independent: x-bar and R chart