Quality Control
Gabriel Molle
Quality control (QC) is a procedure or set of procedures intended to ensure that a manufactured product or performed service adheres to a defined set of quality criteria or meets the requirements of the client or customer. QC is similar to, but not identical with, quality assurance (QA). While QA refers to the confirmation that specified requirements have been met by a product or service, QC refers to the actual inspection of these elements.
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 focused on fulfilling quality requirements".[1]
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.[3]
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 products to uncover defects from the decision to allow or deny product release, which may be determined by fiscal constraints.[6] For contract work, particularly work awarded by government agencies, quality control issues are among the top reasons for not renewing a contract.[7]
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 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.[6]
In project management, quality control requires the project manager and/or the project team to inspect the accomplished work to ensure its alignment with the project scope.[15] In practice, projects typically have a dedicated quality control team which focuses on this area.[16]
Normally, quality testing is part of every stage of a manufacturing or business process. Employees frequently begin testing using samples collected from the production line, finished products, and raw materials. Testing during various production phases can help identify the cause of a production problem and the necessary corrective actions to prevent it from happening again.
Customer service reviews, questionnaires, surveys, inspections, and audits are a few examples of quality testing procedures that can be used in non-manufacturing businesses. A company can use any procedure or technique to ensure that the final product or service is safe, compliant, and meets consumer demands.
Quality Control (QC) is an indispensable aspect of various industries, ensuring that products and services adhere to predefined standards. In the manufacturing sector, QC involves rigorous inspection and testing of raw materials, intermediate components, and final products to maintain consistent quality and minimize defects. In the food industry, QC guarantees the safety and integrity of consumables through thorough testing for contaminants and adherence to health regulations. In the pharmaceutical sector, QC plays a critical role in verifying the potency and purity of drugs, ensuring they are safe for consumption. Additionally, in the software industry, QC involves extensive testing of applications and programs to identify bugs and errors before release, guaranteeing a smooth user experience. Across all industries, QC is a fundamental process that enhances customer satisfaction, boosts efficiency, and fosters a reputation for reliability.
Processes are monitored and adjusted to ensure quality and improve performance. This is typically a technical process using feedback loops, industrial-level controls, and chemical processes to achieve consistency.
Quality control uses specific research tools to accomplish fact-finding processes and conduct analyses. A quality control professional is tasked with analyzing these measurements against some sort of standard determined by the quality management department, company policies, and industries or regulatory bodies. Based on this evidence-gathering, quality control will recommend changes.
We can see from this roadmap, too, how quality assurance and quality control differ. Quality assurance looks at the holistic picture to prevent a product from becoming defective. Quality control, on the other hand, later determines if a product is, in fact, defective or not. Both roles fit under the broad umbrella of quality management.
Even though the terms quality control and quality assurance are sometimes used interchangeably, they have some key differences. Quality criteria, such as ensuring an item complies with specifications, are the main emphasis of quality control. Quality assurance is the sum of all processes and actions necessary to demonstrate that the requirements for quality are satisfied.
Quality control can be a fulfilling job if you enjoy dealing with people, talking, presenting results, and trying to make things better and safer. Depending on the sector, you may need the following qualifications to work as a quality control inspector:
There may be discrepancies because the path to quality assurance and control job varies by industry. However, you'll typically require a number of years of professional expertise in your field. After completing the necessary educational qualifications and gaining the necessary work experience, you are often hired as a quality assurance or control associate.
Depending on the role, expertise, and industry, quality control specialists make a variety of salaries. As you get more expertise and advance into management positions, your pay rises. The average wage, as reported by the Bureau of Labor Statistics, is:
Quality control refers to a company's methods for assessing product quality and, if necessary, improving it. There are various ways to perform quality control, including benchmarking, examining manufacturing procedures, and testing products. All of this is done to keep track of significant product differences.
Quality control is the process by which services/products are measured and tested to ensure they are as uniform as possible and meet a standard. It helps businesses minimize inconsistencies and improve product quality.
The four types of quality control are process control, control charts, acceptance sampling, and product quality control. While a control chart helps study changing processes over time, process control and product quality control help monitor and adjust products as per the standards. Acceptance sampling is a unique type that involves a statistical measure to determine whether a batch or sample of products satisfies the standards.
Some examples of quality control are: a high-speed car manufacturer runs thorough tests for every component, including manual and automated verifications; websites study the average response time per page for customer interactions and generate tickets when the service gets unacceptably slow; retail store owners employ secret shoppers to test the customer service of their stores.
The first step for quality control is to set your quality standards and decide which ones to focus on. Secondly, you must establish operational processes to deliver optimal quality and implement them. The third step is to review your results and identify gaps. Lastly, get feedback and make improvisations.
Inspection and Statistical quality control (SQC) are the two major techniques of Quality Control. Inspection checks the performance of items as per the pre-decided specifications. It involves periodic checking before, during and on completion of the process. It can be categorized into two types: Centralized and Floor Inspection. Statistical Quality Control relies on laws of probability. It controls the production quality within tolerance limits via sample procedure.
Quality Assurance (QA) focuses on preventing defects and maintaining the overall quality management system through process implementation and improvement. It ensures that proper processes are in place to avoid issues. On the other hand, Quality Control (QC) involves detecting and correcting defects through inspections and testing. QC ensures that products or services meet specific quality standards. While QA is proactive, emphasizing prevention, QC is reactive, emphasizing identification and correction of issues after they occur.
Despite declining employment, about 64,300 openings for quality control inspectors are projected each year, on average, over the decade. All of those openings are expected to result from the need to replace workers who transfer to other occupations or exit the labor force, such as to retire.
Quality control inspectors, also called testers, sorters, samplers, and weighers, monitor nearly all manufactured products to ensure that they meet specified standards. Job duties vary across the manufacturing industries in which most of these inspectors work, which include foods, glassware, motor vehicles, electronic components, and structural steel.
Quality control workers use a variety of tools. Although some still use hand-held measuring devices, such as calipers and alignment gauges, workers more commonly operate electronic inspection equipment, such as coordinate-measuring machines (CMMs) and three-dimensional (3D) scanners. Inspectors testing electrical devices may use voltmeters, ammeters, and ohmmeters to test potential difference, current flow, and resistance, respectively.
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