PECB Six Sigma Yellow Belt flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Six Sigma definition

A disciplined, data-driven methodology for reducing process variation and defects to a level of about 3.4 defects per million opportunities, thereby improving quality and customer satisfaction.

DPMO

Defects per million opportunities; calculated as defects divided by the product of units and opportunities per unit, then multiplied by one million. It allows comparison of processes of differing complexity.

Sigma level

A capability metric converting DPMO into a sigma value; 3 sigma corresponds to roughly 66,807 DPMO and 6 sigma to about 3.4 DPMO when the conventional 1.5 sigma shift is applied.

Rolled Throughput Yield

The probability that a unit passes every process step without a defect, computed as the product of the first-pass yields of all steps. It exposes hidden factory rework losses.

First pass yield

The percentage of units that complete a step or process correctly the first time, without rework, scrap, or retest, calculated as good units out divided by units in.

Eight wastes

Lean's non-value-adding categories: transport, inventory, motion, waiting, overproduction, overprocessing, defects, and unused employee skills, remembered by the mnemonic TIMWOODS.

Value-added activity

An activity the customer would willingly pay for that transforms the product or information correctly the first time; anything else is business-value-added or pure waste.

Five Lean principles

Specify value from the customer perspective, identify the value stream, make value flow, let the customer pull, and pursue perfection through continuous improvement.

Cost of poor quality

The total cost of internal failure, external failure, appraisal, and prevention; failure costs are the primary reduction target of Lean Six Sigma improvement projects.

Y equals f of x

The core improvement model stating that output Y, a critical-to-quality characteristic, is a function of process inputs x; projects find and control the critical few x variables.

Critical to quality

A measurable characteristic derived from voice-of-customer data that translates a customer need into a specification with defined target and tolerance limits.

Voice of the customer

Structured collection of customer needs, expectations, and complaints through interviews, surveys, and complaint data, which is then translated into CTQs and project goals.

DMAIC versus DMADV

DMAIC improves an existing process through define, measure, analyze, improve, control; DMADV designs a new process or product through define, measure, analyze, design, verify.

Process capability index

Cp compares specification width to process spread using six sigma of variation; Cpk additionally accounts for centering, so Cpk is always less than or equal to Cp.

Kaizen

A Japanese term for continuous improvement, typically realized through small, incremental, low-cost changes made by the people who perform the work in the process.

Benchmarking

Comparing a process's performance metrics against recognized best-in-class performers or internal reference processes to set realistic improvement targets and identify practice gaps.

Define phase

The DMAIC phase that establishes the project charter, scope, business case, team, customer requirements, and a measurable problem and goal statement with a SIPOC map.

Project charter

A document authorizing the project that contains the business case, problem and goal statements, scope boundaries, team roles, milestones, and expected financial benefit.

SIPOC diagram

A high-level process map showing Suppliers, Inputs, Process steps, Outputs, and Customers; used in Define to set scope and identify process boundaries.

Measure phase

The DMAIC phase that validates the measurement system, defines operational definitions, collects baseline data, and quantifies current process performance and capability.

Operational definition

A precise, unambiguous description of how a characteristic is measured, including the instrument, procedure, and decision criteria, so different people obtain the same result.

Gage R and R

A measurement system analysis that quantifies repeatability (equipment variation) and reproducibility (appraiser variation); percent study variation above 30 percent is generally unacceptable.

Analyze phase

The DMAIC phase that tests data for patterns and statistically verifies root causes of variation and defects, distinguishing true causes from coincidence.

Pareto chart

A bar chart of defect or cause frequencies sorted from largest to smallest with a cumulative line, used to focus on the vital few contributors.

Fishbone diagram

A cause-and-effect diagram that organizes potential causes of a problem into branches such as man, machine, method, material, measurement, and environment.

Five Whys

A root cause technique that repeatedly asks why a problem occurred, typically five times, until the underlying systemic cause rather than a symptom is reached.

FMEA

Failure mode and effects analysis ranks potential failures by a risk priority number, the product of severity, occurrence, and detection scores, to prioritize preventive actions.

Improve phase

The DMAIC phase that generates, selects, pilots, and implements solutions targeting verified root causes, then confirms results against the baseline measurement.

Poka-yoke

A mistake-proofing device or design that prevents an error from occurring or makes an error immediately detectable, removing reliance on operator attention.

Control phase

The DMAIC phase that sustains gains through a control plan, control charts, standard work, response procedures, and transfer of ownership to the process owner.

Control chart

A time-ordered plot of a metric with statistically calculated control limits that separates common-cause variation from special-cause signals needing investigation.

Special cause variation

A non-random signal on a control chart, such as a point beyond the control limits or a run of seven points on one side, indicating an assignable cause.

Process owner

The person accountable for the ongoing performance of a process after the project closes; they maintain the control plan and respond to out-of-control signals.