11 - Accuracy in design and manufacture Flashcards
What is measuring?
The process of using tools such as rules, tapes and gauges to check existing dimensions
What is marking out?
The transfer of designs on to the materials or parts being manufactured to indicate the position of features such as holes and edges
What is accuracy?
The level of conformity of a measurement to the required value
- Accurately fitting parts ensure the correct function of products
- The acceptable range of accuracy is known as the ‘tolerance’
How can accuracy be improved?
The use of datum edges and surfaces, as well as horizontal lines generated by laser levels
- provides reference points, which improve accuracy
What is a datum?
The reference surface or edge from which measurements are taken to improve accuracy
5 ways in which testing can eliminate errors
- Dials on manual machine controls allow precision movement of tools and work pieces
- Digital test gauges are very accurate measuring devices. They are often linked to a computer
- Profile projectors measure fine details to an accuracy of 0.015mm
- CNC machines use computer codes to control their movement and ensure accuracy
- Laser micrometers, material thickness sensors, alignment systems are all examples of non-contact devices that improve accuracy
What are the 3 measuring aids?
- Jigs
- Fixtures
- Templates
Jig
A device that guides tools such as drills
- Improves accuracy, allows for repetitive machining operations
- Eliminates the need for marking out
- Eliminates need for high-skilled workers. Eliminates human error
Fixture
Maintains the accurate alignment of parts for processes such as welding
- Provides a framework which the part is clamped to
- Ensure that every manufactured assembly is of high quality with minimal rejects
Template
Rigid shape, ensures consistent repetition of the same outline, by providing a consistent profile for marking out and outlining identical pieces
