Intended learning outcomes: Produce an overview on tools used in quality control in their original usage stemming from production engineering. Identify deliverables of the Measure phase as well as the Analyze phase.
Quality control encompasses the operational techniques and the activities used to fulfill and verify requirements of quality [ISO8402].
Quality control aims to implement predefined targets from quality planning in reality; that is, it measures for conformance to quality requirements. The techniques of quality control can be used for both monitoring a process and correcting or eliminating defects or failures.
In the PDCA cycle, the Check phase comprises the necessary tasks of quality control. In order to control the success of the Do phase, the respective tools have to be implemented before the Do phase and used for rechecking afterwards. In the Six Sigma method, quality control comprises two of the DMAIC phases, namely, Measure, and Analyze. Again, in order to control the success of the Improve phase, the respective tools have to be implemented before the Improve phase and used for rechecking afterwards.
In the Measure phase, the task is to determine how the spoken needs of the customers, the CTQs, will be specified in measurable terms using tools. The appropriate measurement system is then installed or an existing system improved. Here see Section 18.1.4. Further, actual current performance is quantified and the target goal determined (for example, increase process stability from three sigma to four sigma).
Some quality control tools and tests for this task are, for example, ABC classification or Pareto chart, sampling plans, and statistical process control to determine process capability and process performance.
The deliverables of the Measure phase can be reviewed and revisited as follows:
- Is there agreement on the critical characteristics, and is there a detailed description of their measurability?
- Has a plan been drawn up showing what data will be captured and what measurement system will be used? Have the data been gathered?
- Has the current variation of the process (current sigma level) been calculated and opportunities for improvement defined?
In the Analyze phase, the task is to identify root causes of variation and defects. Now it is important to provide statistical evidence of current deviations and to then formulate options for improvement (improvement goals). Thus, the Measure and Analyze phases both encompass activities of quality control.
Quality control in its original usage stems from production engineering. The tools used include risk analysis, such as failure mode and effects analysis (FMEA), design of experiment (DOE), and hypothesis testing, such as analysis of variance (ANOVA) and multivariate analysis of variance (MANOVA).
Further tools for this step are cause and effect diagram (fishbone, or Ishikawa diagram), histograms, quality control charts, correlation diagrams, checklists, and general graphical representations, such as time series diagrams, pie charts, bar charts, Gantt charts, or network diagrams.
The deliverables of the Analyze phase can be reviewed and revisited as follows:
- Were data and process analysis conducted and the gaps between actual and target process performance determined?
- Have the root causes of variation and defects been found and prioritized according to importance?
- Were the performance deficits communicated and converted to financial quantities? (Here see the discussion in Section 1.3.1 on opportunity costs.)
Course section 18.2: Subsections and their intended learning outcomes
18.2 Quality Management Tasks at the Operations Level
Intended learning outcomes: Produce an overview on the Deming Cycle (PDCA Cycle) and the Shewhart Cycle as well as the Six Sigma Phases. Present the phases of quality planning, control, assurance, and activation of the Deming Cycle. Describe the Six-Sigma phases of define, measure, analyze, improve, and control. Differentiate between continual improvement and reengineering.
18.2.1 The Deming Cycle (PDCA Cycle) and the Shewhart Cycle
Intended learning outcomes: Produce an overview on The Shewhart cycle developed in statistical quality control. Present the Deming cycle. Describe quality management tasks in the Deming cycle.
18.2.2 DMAIC — The Six Sigma Phases
Intended learning outcomes: Present DMAIC, the Six Sigma phases. Describe the tasks in the Six Sigma phases. Differentiate between DMAIC, RDMAIC, DMAICT, and DMADV.
18.2.3 Quality Planning: PDCA Plan Phase — DMAIC Define Phase
Intended learning outcomes: Identify the cause of differences between stakeholders’ expectations and actual product or process characteristics.
18.2.3b Quality Planning: Quality Function Deployment (QFD)
Intended learning outcomes: Explain quality function deployment – the house of Quality and 10 steps of implementation.
18.2.3c Quality Planning: First-Pass Yield (FPY), SIPOC diagram and Critical-to-Quality (CTQ) matrix
Intended learning outcomes: Explain the first-pass-yield thinking. Describe the SIPOC diagram and the CTQ matrix.
18.2.4 Quality Control: PDCA Check Phase, Part 1 — DMAIC Measure Phase and Analyze Phase, Part 1
Intended learning outcomes: Produce an overview on tools used in quality control in their original usage stemming from production engineering. Identify deliverables of the Measure phase as well as the Analyze phase.
18.2.5 PDCA Do Phase — DMAIC Improve Phase
Intended learning outcomes: Produce an overview on tools of the jidoka concept, such as Andon (or a visual control system in a job shop) and Poke yoke (or fail-safe techniques).
18.2.6 Quality Assurance: PDCA Check Phase, Part 2 — DMAIC Measure Phase and Analyze Phase, Part 2
Intended learning outcomes: Identify changing definitions of terms over time in quality assurance and quality management.
18.2.7 PDCA Activation Phase — DMAIC Control Phase
Intended learning outcomes: Produce an overview on tools used in quality activation. Identify deliverables of the Control phase.
18.2.8 Project Management, Continual Improvement, and Reengineering
Intended learning outcomes: Differentiate between continual process improvement and (business) process reengineering.
