Quality Control (QC) is a technique used in all areas of manufacturing. It is a technique used to check quality against a set standard or specification. It may be used to check the dimensions of a product or component. We say that the component has been checked to ensure that it is within accepted tolerances (acceptable variations of sizes which stray from the optimum size).
Quality Control requires constant inspection throughout the manufacturing process in order to detect products which are not up to the required standard. These inspections are also carried out on the completion of a product by trained inspectors. |
| Quality Assurance (QA) is a a companies guarantee that the product or service it offers meets the accepted quality standards. The planned checking procedures take place 'before, during and after' and the aim is to get it ' right first time, every time'. Quality Assurance must be the responsibility of everybody involved in the creation of a product or service. QA must be built into every stage of product development and every stage of the manufacturing process. |
| Total Quality Management (TQM) takes Quality control even further. Its aim is to create a Quality Culture . A company that embraces (TQA) is a company that is continually attempting to improve its products and its performance. Customers tend to be loyal to this type of organisation. |
Jigs
There is a big difference between making a one-off product and a number of identical products. These items may need to have holes drilled in exactly the same places. They may need to have identical shaped folds or forms.
In order for us to guarantee that a number of products are exactly the same we need to make tools (Jigs) which are used throughout the manufacturing process. These jigs may possibly be:
Drilling Jigs
Folding or Shaping Jigs
Cutting Jigs |
Tolerances
When we describe the word tolerance we are really defining how much variation from a precise size specification can be allowed. It would be ideal for there to be no variation at all this is called zero tolerance but in reality this is very difficult to achieve. To achieve zero tolerance costs more money.
Some products for example computer chips and some engineering components have to be accurate to +- 10 microns ( 10 microns above or below the optimum size).
Other products for example a garden shed may be accurate to +- 50mm.
Quality Control Gauge
Throughout the manufacture of a product or component we have already looked at the use of quality control checks.
As a machine operator produces a number of products (A Batch) it is important to find out if the parts or components are all the same size or are in acceptable tolerances.
In order for the person to do this a GO/NO GO gauge is needed. This simple device may check the diameter, length or width of a product.
A GO/NO GO GAUGE.
1. How accurate does each part of your clock need to be?
2. What tolerances will you work to?
3. How will you check them?
Design your own QC Guage to check your work.
Make a jig to accurately drill the hole for the mechanism.
See the Car Scraper Project |
Programmes of Study
3l To ensure that the quality of their products is suitable for intended users.
4a To match materials and components with tools, equipment and processes;
4b To use tools and equipment accurately and efficiently to achieve an appropriate fit and finish and reliable functioning in products that match the specification;
4c A range of industrial applications for a variety of familiar materials and processes;
4k To apply and devise test procedures to check the quality of their work at critical points during development, and to indicate ways of improving it;
4l To ensure through testing, modification and evaluation, that the quality of their products is suitable for intended users.
5a How materials are cut, shaped and formed to designated tolerances |
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