Quality control (QC) is a process by which entities review the quality of all factors involved in
production.
ISO 9000 defines quality control as "a part of
quality management
Quality management ensures that an organization, product or service consistently functions well. It has four main components: quality planning, quality assurance, quality control and quality improvement. Quality management is focused not on ...
focused on fulfilling quality requirements".
This approach places emphasis on three aspects (enshrined in standards such as ISO 9001):
# Elements such as controls, job management, defined and well managed processes, performance and integrity criteria, and identification of records
# Competence, such as knowledge, skills, experience, and qualifications
# Soft elements, such as personnel,
integrity,
confidence,
organizational culture,
motivation,
team spirit, and quality relationships.
Inspection is a major component of quality control, where physical product is examined visually (or the end results of a service are analyzed). Product inspectors will be provided with lists and descriptions of unacceptable
product defects such as
cracks or surface
blemishes for example.
History and introduction
Early
stone tools such as
anvils had no holes and were not designed as
interchangeable parts.
Mass production established processes for the creation of parts and system with identical dimensions and design, but these processes are not uniform and hence some customers were unsatisfied with the result. Quality control separates the act of
testing
An examination (exam or evaluation) or test is an educational assessment intended to measure a test-taker's knowledge, skill, aptitude, physical fitness, or classification in many other topics (e.g., beliefs). A test may be administered verba ...
products to uncover defects from the decision to allow or deny product release, which may be determined by fiscal constraints.
For contract work, particularly work awarded by government agencies, quality control issues are among the top reasons for not renewing a contract.
The simplest form of quality control was a sketch of the desired item. If the sketch did not match the item, it was rejected, in a simple
Go/no go procedure. However, manufacturers soon found it was difficult and costly to make parts be exactly like their depiction; hence around 1840 tolerance limits were introduced, wherein a design would function if its parts were measured to be within the limits. Quality was thus precisely defined using devices such as
plug gauges and
ring gauges. However, this did not address the problem of defective items; recycling or disposing of the
waste
Waste (or wastes) are unwanted or unusable materials. Waste is any substance discarded after primary use, or is worthless, defective and of no use. A by-product, by contrast is a joint product of relatively minor economic value. A waste pr ...
adds to the cost of production, as does trying to reduce the defect rate. Various methods have been proposed to prioritize quality control issues and determine whether to leave them unaddressed or use
quality assurance techniques to improve and stabilize production.
Notable approaches
There is a tendency for individual consultants and organizations to name their own unique approaches to quality control—a few of these have ended up in widespread use:
In project management
In
project management
Project management is the process of leading the work of a team to achieve all project goals within the given constraints. This information is usually described in project documentation, created at the beginning of the development process. T ...
, quality control requires the project manager and/or the project team to inspect the accomplished work to ensure its alignment with the project scope.
In practice, projects typically have a dedicated quality control team which focuses on this area.
See also
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Analytical quality control
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Corrective and preventative action (CAPA)
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Eight dimensions of quality
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First article inspection
A First Article Inspection (FAI) is a design verification process for verifying that a new or modified production process produces conforming parts that meet the manufacturing specification detailed in technical or engineering drawings. Typically, ...
(FAI)
*
Good Automated Manufacturing Practice (GAMP)
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Good manufacturing practice
Current good manufacturing practices (cGMP) are those conforming to the guidelines recommended by relevant agencies. Those agencies control the authorization and licensing of the manufacture and sale of food and beverages, cosmetics, pharmaceut ...
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Quality assurance
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Quality management framework
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Standard operating procedure
A standard operating procedure (SOP) is a set of step-by-step instructions compiled by an organization to help workers carry out routine operations. SOPs aim to achieve efficiency, quality output, and uniformity of performance, while reducing misc ...
(SOP)
*
QA/QC
References
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Further reading
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External links
ASTM quality control standards
{{Authority control
Design for X
Statistical process control
Quality management