Module 5: Quality

Question 1

Performance quality

Answer 1

To what extent the product or service provided meets customer expectations

Question 2

Conformance quality

Answer 2

Whether the process is carried out the way that we intend it to be carried out

Question 3

Cause for conformance quality issues

Answer 3

Variability

Question 4

Yield of a resource

Answer 4

% of units the resource produces according to specification

Question 5

Yield of process

Answer 5

% of units the process produces according to specification

= y_1 * y_2 * … * y_n = (1-p)^n

Question 6

Swiss cheese model

Answer 6

Probability of an overlapping defect (hole) in all slices of cheese

Question 7

Cost of defect: Input or output price?

Answer 7

Depends on point of detection - before or after bottleneck

Question 8

Starved (resource)

Answer 8

Resource is not utilized due to rework at preceding resource

Question 9

Blocked (resource)

Answer 9

Resource has completed processing but cannot progress due to rework at next resource

Question 10

Buffer vs Toyota argument on inventory

Answer 10

Buffer: Increase inventory to avoid flow rate impact from production issues
Toyota: Decrease inventory to expose problems and address them

Question 11

Kanban system

Answer 11

Visual way to implement a pull system. Amount of WIP is determined by number of cards

Question 12

Why is inventory the worst form of waste?

Answer 12

Operators grow comfortable with current amount of defects instead of trying to improve

Question 13

Upper specification limit (USL)

Answer 13

Level above which a unit will be considered defective

Question 14

Lower specification limit (LSL)

Answer 14

Level below which a unit will be considered defective

Question 15

Capability score

Answer 15

(USL - LSL) / (6 * sigma)

Question 16

ppm

Answer 16

Parts per million. Used to describe number of defective units per one million produced

Question 17

Common cause variation

Answer 17

Signified by variation within control limits

Question 18

Assignable cause variation

Answer 18

Signified by variation outside control limits

Question 19

Control limits (LCL and UCL)

Answer 19

Measure level of variation in a product relative to its usual fluctuations (ie. w/in 3sd in each direction). Not related to whether or not defective

Question 20

Process control chart

Answer 20

[TBD]

Question 21

Capability analysis

Answer 21

1st step in process control: What is the inherit capability of my process when it is “in control”?

Question 22

Conformance analysis

Answer 22

2nd step in process control: Identify when control has likely been lost and assignable cause variation has occurred

Question 23

Investigate for assignable cause

Answer 23

3rd step in process control: Find root causes of potential loss of statistical control

Question 24

Eliminate or replicate assignable cause

Answer 24

4th step in process control: Need corrective action to move forward

Question 25

Information turnaround time (ITAT)

Answer 25

Amount of time before a defective is detected => slow feedback and improvement

Question 26

Jidoka

Answer 26

If equipment malfunctions / gets out of control, it shuts itself down to prevent further damage. Requires three steps: 1) Detect, 2) Alert, 3) Stop

Question 27

Andon Board / Cord

Answer 27

Assembly line version of Jidoka. When a worker notices a defect, s/he pulls the andon / cord. Station # appears on andon board.

Question 28

Toyota quality system diagram

Answer 28

[TBD - ]

Question 29

3 commonalities between Toyota Quality System & Six Sigma

Answer 29

1) Avoid defects by eliminating variation
2) If variation exists, create an alarm and trigger process
3) Process is never perfect - repeat steps

Question 30

Ishikawa diagram

Answer 30

Brainstorming technique of what might have contributed to a problem.
Fish-shaped.

Question 31

5 Why’s

Answer 31

Technique from Toyota to get to the root of a problem

Question 32

Pareto chart

Answer 32

Maps out the assignable causes of a problem in the categories of the Ishikawa diagram. Order root causes in decreasing order of frequency of occurence - 80/20 logic.

Question 33

Pareto principle

Answer 33

80% of the problems are caused by 20% of the root causes

Question 34

Three enemies of operations

Answer 34

Variability, Waste, Inflexibility