17 Quality assurance and quality control Flashcards
What is quality assurance (QA)?
QA is a procedure or system which is followed in order to achieve the desired level of quality.
What does an effective quality assurance procedure involves?
- Measurement of variables
- Comparisons with specifications
- Constant monitoring of processes
- Using feedback loops to prevent errors
What does Quality assurance focus on?
It focuses on defect prevention
What are simple planning systems?
A simple way to plan a sequence of manufacturing events is by using a flowchart
What is a flowchart? And how can they help?
- A flowchart is a type of diagram that shows a workflow or process and is usually read top to bottom.
- They highlight critical control points and allow feedback.
- Flowcharts help manufacturers to identify possible problems such as bottlenecks
What does a giant chart showcase?
- The phases of a project
- Individual tasks
- Key milestones
- Required resources
- Tasks are usually shown on the vertical axis whilst timings are recorded on the horizontal axis
What is total quality management?
Based on the principles of Kaiserslautern, it is a customer focused, process cantered strategy
Key features of total quality management
- Integrated strategies and systems
- Employee involvement
- Communication
- Constant feedback
- Continuous improvement
What is scrum?
Scrum is a quality driven, agile framework for managing product development and problem solving.
How does a scrum work?
- Scrum is initiated by the product owner with a product backlog (a wish list of items to bring to the market)
- The scrum master leads scrum team in series of sprints (shorter focused tasks delivered by the team)
- Scrum uses different types of sprint meetings and lists to ensure everything is kept on track.
What is a sprint backlog?
The sprint backlog is a list of products to produce in the next sprint.
What is the scrum board?
It contains a list of tasks for each team member and tracks their progress
What are the four types of meeting in scrum meetings?
Sprint planning, daily ‘stand ups’, sprint review and sprint retrospective
Sprint planning def
Used to set up the sprint parameters
Daily ‘stand ups’
Used to check if everything is going to plan
Sprint review
Used to deliver the results and get feedback
Sprint retrospective
Used to reflect on what can be improved
What does six sigma aim to do?
Improve process and management performance
What are the five phases of six sigma?
Define, measure, analyse, improve, control
What do you do in ‘six sigma’
- Identifying and removing the main causes of errors improves efficiency, productivity and quality and limits waste
- Many large corporations now use Six sigma
What planning and charting projects are used?
- Project evaluation and review techniques (PERT)
- Critical path analysis (CPA) or critical path method (CPM)
What does PERT and CPM rely on?
An arrow and node diagram
What do PERT and CPM calculate?
They calculate the longest path of all planned activities to their individual end points or to the end of the project
What does it mean when ‘tasks’ float?
It means that there is room for time to be delayed without making the project longer.
What is CPA?
It is a 6 step method used to plan sequential activities, showing them as nodes, usually boxes joined with arrows with each box including details of the duration of each task
What are the stages of CPA?
Stage 1: Specify each task
Stage 2: Sequence activities
Stage 3: Draw network diagram
Stage 4: Estimate timelines
Stage 5: Identify the critical path
Stage 6: Update diagram to show progress
What does PERT stand for?
Project evaluation and review
What do measuring materials require?
They require tools with accurate reference or ‘datum’ points - surfaces or edges from which all other measurements are taken.
Examples of measuring tools?
- Traditional tools such as rulers, squares, callipers and gauges
- Digital micrometres and callipers
- Laser and probe scanners
- A dial test indicator or DTI uses a probe to test accuracy from a specific reference point
What is tolerance?
This is a margin of error to ensure that a product has absolute accuracy and tolerance. This can apply to hole depth, length, angle, thickness, weight, elasticity and so on.
What is a go-no gauge?
It can be used to test components to see if sizes fall within a given tolerance
Where is tolerance used and what happens if the product is not within the tolerance?
They will be rejected during quality control checks.
What does quality control ensure?
QUALITY CONTROL ENSURES PRODUCT STANDARDS ARE MET. Various tools are used to ensure parts have dimensional accuracy and are within tolerance.
What are visual checks?
They are still used to check quality throughout the production process to ensure that:
- Supplied materials comply with the manufacturer’s requirements
- Parts and components are within tolerance
- Finished products and components match the product design specification
- Products comply with relevant standards
What is Coordinate Measuring Machinery used for? (CMM)
It is used to check the measurements of finished components
What does probe scanning do?
- Uses a calibrated probe pin and highly sensitive sensors
- Tests dimensional accuracy
- Can scan dynamically along a surface or measure using predetermined data points
- Enables comparison of points against 3D CAD models
What is laser scanning and what does it do?
- This uses a laser reflected off the surfaces of a product
- Can take thousands of accurate measurements very quickly
- Creates an accurate comparative 3D CAD model
- Can spot potential wear and tear in a system and accurately predict maintenance
What is non-destructive testing?
These can be used to measure wall thicknesses and detect internal faults not visible to the naked eye.
What are two examples of Non-destructive testing NDT
Ultrasound
x-ray analysis
