Conceptual Understanding: Designers should ensure that the quality of products is consistent through development of detailed manufacturing requirements. They also need to focus on the means to achieve it. The importance of quality management through quality control (QC), statistical process control (SPC) and quality assurance (QA) reduces the potential waste of resources.
New words to know:
Tolerance: The allowable amount of variation within a particular quality. i.e. The weight tolerance for a high performance bicycle frame might be +/- 100 grams from its set weight of 1850 grams.
Destructive Testing: Testing a product or part that destroys or physically alters the part. These are usually mechanical properties such as heat resistance, compression, toughness.
Non-destructive Testing: Testing a product or part that measure physical properties. The product itself is not damage or changed in the process: Weighing, checking colour, confirming dimensions.
Inspection: The checking of qualities at difference stances of the production process.
QA- Quality Assurance (Process): This covers all activities from design to documentation.
The goal of QA is to reduce or avoid errors or defective products being delivered to the customer.
This covers all activities from design to documentation.
It also includes the regulation of quality of:
raw materials
Assemblies
products and components
services related to production
management and inspection processes
Example:
The testing of raw materials when they arrive at the manufacturer to ensure they meet the requirements and quality needed to manufacture a product. By identifying inferior materials earlier in the producing stage, costly errors, waste, and downtime can be avoided later on.
QC- Quality control (Product): Involved in development systems to ensure that products or services are designed and produced to meet or exceed customer requirements and expectations.
The goal of quality control is to produce the same part over and over again with a minimum or no waste.
Tolerances are defined at the design stage of the machinery. Parts not within tolerance need to be reworked or scrapped. Continuous monitoring ensures that the machines perform to the predetermined standard to produce quality product. Quality control at the source eliminates waste from defects as workers are responsible for the quality of the work they do.
Example:
Parts that do not fall within the tolerance range are either reworked or discarded. A CIM system continuously monitors machines and production and ensures machines are operating at tolerance, in addition to identifying when a machine needs maintenance or recalibration.
SPC- Statistical process control: A quality control tool that uses statistical methods to ensure a process is operating at its most efficient.
The goal of SPC is to reduce waste, increase productivity, and discover abnormalities in a process in order to facilitate timely decision making.
SPC is achieved through measuring aspects of a component to ensure that it meets the required standard throughout its production in order to eliminate waste.
SPC decreases the likelihood the finished product will need to be reworked and can also identify bottlenecks, waiting times, and other sources of delays within the process. SPC emphasises early detection and prevention of problems, rather than the correction of problems after they have occurred.
Example:
Car manufacturers collecting data on types and frequency of repairs, rate of wear and tear on parts such as brake pads, and data from car accidents and crashes in order to improve quality and safety of the automobile.