Benefits of Using Quality Control in Manufacturing
Customers expect and demand high-quality products. When customers receive quality products you will:
- Increase customer loyalty
- Gain repeat business
- Gain new customers from referrals
- Maintain or improve your position in the market
- Improve safety
- Reduce liability risks
- Contribute to overall positive branding of your product
Manufacturers with quality control procedures in place are far less likely to face product recalls or place customers at risk from poorly made products. The cost associated with these recalls can be steep. Testament to this is the Takata recall, which is estimated to cost the company between $7 and $24 billion.
Discover how you can avoid costly recalls and support your quality control system with TPM. Graphic Products’ Best Practice Guide to Total Productive Maintenance (TPM) will help you on the road to total quality. Improve quality, eliminate defects, and increase your profits.
Quality Control, QA and Lean Manufacturing
Lean manufacturing tools can bolster your company’s quality program. Lean revolves around improving quality and safety while increasing efficiency and profits. Some powerful lean manufacturing tools that can bolster your quality system include:
- TPM improves product quality by eliminating downtime, defects, and accidents. TPM accomplishes this through comprehensive maintenance programs and operator training.
- Kaizen helps eliminate problems at their source by empowering workers to find and solve problems on a daily basis.
- 5S helps organize and standardize the workplace. Take control with the 5S System Best Practice Guide, by Graphic Products. Improve procedures and eliminate errors in your facility.
While every facility has different needs and may require a different lean tool, using lean to support quality control is essential. Procedures will be simplified, and the number of errors will be reduced.
Learn more about Kaizen and how it can help improve quality with this helpful video.
Craft and tradespersons Edit
The Industrial Revolution led to a system in which large groups of men performing a similar type of work were grouped together under the supervision of a foreman who also took on the responsibility to control the quality of work manufactured.
Quality Assurance has developed a good deal during the last 80–90 years (in about 20 year intervals) from its inception to the current state of the art.
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Wartime production Edit
SQC had a significant contribution in that it provided a sampling inspection system rather than a 100 per cent inspection. This type of inspection however did lead to a lack of realisation to the importance of the engineering of product quality.
After World War II, the United States continued to apply the concepts of inspection and sampling to remove defective product from production lines. However, there were many individuals trying to lead U.S. industries towards a more collabrative approach to quality.
Excluding the U.S., many countries’ manufacturing capabilities were destroyed during the war. This placed American business in a position where advances in the collabrative approaches to quality were essentially ignored.
How an EQMS Improves Quality Control (and Assurance)
Increasingly more organizations have begun to understand how an optimal EQMS can ensure that each product meets specific efficacy, safety, quality and compliance requirements. A robust EQMS will automate, monitor and effectively manage all core areas necessary to maintain quality in products and processes, including:
Quality audits — An EQMS will streamline and better manage the entire audit process, from scheduling and planning through execution and completion; automate scheduling of all recurring audit-related activities; and leverage advanced tracking, analytics and reporting capabilities for a real-time view of the audit process.
Quality events — An EQMS will enable you to more effectively identify, evaluate and handle nonconformance, deviations, customer complaints and other quality events; automate data collection, routing, follow-up and escalation of quality events; and leverage forms and processes that connect personnel for quick disposition of a nonconformance.
Corrective and preventive action (CAPA) — An EQMS with strong CAPA capabilities will automate and more effectively manage every step of CAPA implementation, from identification of the problem through corrective action; integrate the CAPA process with other quality processes, such as nonconformance and audit; and help keep your quality system always ready for inspections and audits.
Change control — An end-to-end EQMS will allow you to streamline the entire change control process and quality control system; leverage forms that incorporate priority level and prompt risk assessment and classification of the change; and customize reports that will provide real-time status of change control tasks as well as the entire quality system.
Document control — An EQMS with robust document management abilities will enable you to automate and better manage all tasks relating to documents-based processes; maintain all documentation in a single repository; and integrate quality processes like CAPA and audits.
Training management — A robust EQMS will automate the assigning and monitoring of training tasks; and integrate training management with the rest of the quality control system, so any change to a quality document or process that requires new training will automatically prompt training tasks upon approval of the change.
Risk — An integrated EQMS can help organizations identify and mitigate long-term systemic risks by tracking and analyzing the recurrence of issues; unify all risk-related activities and documentation in a single, centralized repository; automatically receive information (about a deviation, for example) that triggers a risk analysis; and gain a complete view of risk across product lines, business processes and business units.
A comprehensive EQMS is designed to work as a single end-to-end solution, rather than a combination of components (often from multiple vendors), and will help an organization address critical aspects of quality control and assurance, as well as risk management as it relates to quality management. Some vendors can offer solutions that extend beyond the quality department, connecting other processes and functions. A prime example of this is MasterControl Manufacturing Excellence, which lets you bring quality control and quality assurance directly to the shop floor.
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:
|Terminology||Approximate year of first use||Description|
|Statistical quality control (SQC)||1930s||The application of statistical methods (specifically control charts and acceptance sampling) to quality control:556|
|Total quality control (TQC)||1956||Popularized by Armand V. Feigenbaum in a Harvard Business Review article and book of the same name.; stresses involvement of departments in addition to production (e.g., accounting, design, finance, human resources, marketing, purchasing, sales)|
|Statistical process control (SPC)||1960s||The use of control charts to monitor an individual industrial process and feed back performance to the operators responsible for that process; inspired by control systems|
|Company-wide quality control (CWQC)||1968||Japanese-style total quality control.|
|Total quality management (TQM)||1985||Quality movement originating in the United States Department of Defense that uses (in part) the techniques of statistical quality control to drive continuous organizational improvement|
|Six Sigma (6σ)||1986||Statistical quality control applied to business strategy; originated by Motorola|
|Lean Six Sigma (L6σ)||2001||Six Sigma applied with the principles of lean manufacturing and/or lean enterprise; originated by Wheat et al.|
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*Editor’s note: This post was originally published in 2011, and has since been updated to include new information and formatting.
What Are The Methods Involved In Quality Improvement?
Following are the globally accepted and recognized methods for Quality Improvement:
This model comprises of four steps- focus (on the process to be improved), analyze (collection and analysis of data to find possible solutions), Develop (data plans for improvement, implementation, and communication), Execute and Evaluate (implementation of data plans).
Another important method of Quality Improvement is based on the PDSA model which involves a combination of building and applying knowledge. PDSA model comprises of Plan, Do Study and Act. This process runs as a cycle and needs to be repeated.
It is one of the most important methods of Quality Improvement. The term ‘Six Sigma’ is derived from the Greek letter, Sigma which denotes standard deviation of time from the mean. Six Sigma equals 3.4 defects or errors per million. It is a measurement-based strategy of quality improvement and finds great success in problem reduction.
Quality Assurance with Quality Control
Quality assurance streamlines production and helps to ensure that the final products meet the company’s quality criteria. It ensures that the processes used to design, test, and produce products will be done correctly.
In manufacturing, quality assurance approaches, like ISO 9001, help manage and improve many processes, including:
- Acquiring raw materials
- Purchasing third-party components and sub-assemblies
- Designing and using inspection procedures
- Complying with production processes
- Responding to defects
For every business, quality assurance is different. However, ISO 9001 works for businesses both large and small and can be adapted for most any need. It provides the means for creating a lasting quality assurance program, ensuring that everything, from raw materials to inspection procedures are of the highest quality. Issues and defects from poor quality materials or third-party components are all but eliminated.
What is a quality inspection?
An inspection is an activity such as measuring, examining, testing or gauging one or more characteristics of a product and comparing the results with specified requirements in order to establish whether conformity is achieved for each characteristic. (This definition comes from the ISO 2859 standard, which is derived from MIL-STD 105 E.)
The term inspection refers to the activity of checking products, whereas audit applies to analyzing manufacturing processes and/or systems. The quality inspector usually follows a pre-established checklist that is based on the product specifications. Inspected products can be the components used for production, semi-finished goods, or (most often) finished goods before shipment to a customer.
We drew an infographic a few years ago that shows the main steps in a typical quality check based on random sampling.
Prefer to learn about quality inspections by watching a video presentation?
Hit the play button below to get started, or click this link if the player isn’t visible:
A look at AQL in more detail
As I wrote above, the ‘AQL’ is the “quality level that is the worst tolerable” on average over a period covering a number of batches.
In practice, three types of defects are often distinguished. For most consumer goods, the limits are:
- 0% for critical defects (totally unacceptable: a user might get harmed, or regulations are not respected).
- 2.5% for major defects (these products would usually not be considered acceptable by the end user).
- 4.0% for minor defects (there is some departure from specifications, but most users would not mind it).
These proportions vary in function of the product and its market. Components used in building an airplane are subject to much lower AQL limits.
Note that this tool is used mostly during final outgoing inspections (when the products are ready to be shipped out), and sometimes during production (when the number of products is sufficient to have an idea of the batch’s average quality).
Incorrect Implementation of Quality Control in Manufacturing
Quality control in manufacturing can be a little tricky. Often, it is done at the end of the production process, only catching defects after the fact.
Effective quality control is more involved and should include two levels:
- Operators monitor the manufacturing process and ensure that there is little variation.
- Engineers routinely monitor the product design for issues. When a problem is found, it is immediately fixed.
By monitoring products at the end of production as well as reviewing the products’ design, companies can solve problems more efficiently, saving time and money.
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Армейские ПесниКлассика пианиноМузыка из рекламыДетские песни из мультфильмовМузыка для аэробикиСборник песен 70х годовДля любимого человекаКлассика в современной обработкеКлубные миксы русских исполнителей3D ЗвукДальнобойщикиЗарубежный рэп для машиныТоповые Клубные ТрекиМощные БасыДискотека 2000Песни про папуХристианские ПесниЗимняя МузыкаМузыка Для МедитацииРусские Хиты 90ХГрустная МузыкаRomantic SaxophoneТанцевальный хип-хопНовогодние песниЗарубежные хиты 80 — 90Песни про покемонаРомантическая МузыкаМотивация для тренировокМузыка для сексаМузыка в машинуДля силовых тренировокПремия «Grammy 2017»
Basu, Ron, and J. Nevan Wright. Quality Beyond Six Sigma. Elsevier, 2003.
Brownhill, Mark. «Beyond Poka-Yoke.» Fabricating & Metalworking. February 2005.
Irwin, Stephen. «ISO 9000—A plus for airports: consultant Steve Irwin offers reasons why airports can benefit from a new standard.» Airport Business. March 2006.
Juran, Joseph M. Architect of Quality. McGraw-Hill, 2004.
«The Life and Contributions of Joseph M. Juran.» Carlson School of Management, University of Minnesota. Available from http://part-timemba.csom.umn.edu/Page1275.aspx. Retrieved on 12 May 2006.
Montgomery, Douglas C. Introduction to Statistical Quality Control. John Wiley & Sons, 2004.
«Real-World Six Sigma.» Industrial Engineer. September 2005.
«Teachings.» The W. Edwards Deming Institute. Available from http://www.deming.org/theman/teachings02.html. Retrieved on 12 May 2005.
Advantages of Effective QC
When a manufacturing facility has a good QC system in place, they will benefit in many ways. These benefits don’t stop just at the manufacturing company, but extend to customers, vendors, employees, and more. The following are some of the key advantages to having an effective QC system in place:
- Customer Loyalty — Quality control helps to reduce the risk of a defective product making it into the hands of customers. Providing customers a consistently positive experience will improve their loyalty to the brand.
- Reduced Waste — Being able to identify quality issues quickly will reduce the amount of waste produced due to defective products.
- Compliance — In many manufacturing industries, there are compliance, environmental, and other regulations that must be met. QC programs can focus on these areas to ensure compliance.
- Customer Referrals — Customers who receive consistently high quality products are more likely to refer their friends and family to that brand.
- Improved Safety — A defective product is often a dangerous product. QCl can find and eliminate potential safety issues early on.
- Employee Empowerment — In most quality control systems all employees are encouraged to take steps to identify issues. This can help to empower employees, which can lead to improved morale.
- Increased Profits — Allowing defective products to continue to be made can result in very costly recalls, lost customers, and an overall drop in profitability.
- Corporate Image — Companies are often known for their great reliability. This accomplishment starts with a great quality control department.
These are just the most tangible benefits of an effective QC system in manufacturing. There are also many secondary, advantages that a company will enjoy. Taking the time to implement and improve QC systems will help any business improve over time.
How to Implement Quality Control in Manufacturing
To implement an effective quality control program, first create and document your approach to quality control. This includes:
- Defining the quality standards for each product
- Selecting the quality control method
- Defining the number of products/batch that will be tested
- Creating and training employees for quality control
- Creating a communication system for reporting defects or potential issues.
Next, you will need to create procedures for handling defects. Consider the following:
- Will batches be rejected if defected items are found?
- Will there be further testing and potential repair work involved?
- Will production be halted to ensure that there are no more defective products created?
- How will new product versions be handled?
Finally, use a method like 5-Whys to identify the root cause of the defect, make any needed changes, and ensure your products are defect free.
When Did It Begin
The concept of using a system to enforce quality levels dates to the Middle Ages, a historical era in Europe spanning from the fifth to the fifteenth century. During this period craftsmen formed guilds (associations of workers involved with the same trade), which created specific rules pertaining to issues of quality in the construction of tools, textiles, and other products. Craftsmen who did not observe the standards required by the guild (for example, by building a product of poor quality) faced fines or, in extreme cases, expulsion from the guild.
In the nineteenth century the manufacturing industry widely adopted the system of division of labor, in which individual workers are assigned responsibility for one specific aspect of the production process. With this system the responsibility for quality control shifted from the individual craftsmen to the foreman, a supervisor who oversees certain aspects of manufacturing operations. Another important development in quality control was statistical process control, a system that analyzes the process of production rather than the actual finished product. It was pioneered by Walter A. Shewhart (1891–1967), a prominent American engineer and statistician. During World War II (1939–45) statistical process control became the predominant form of quality control.
Example of a quality inspection checklist
Part of the job is to pick samples and think “would a consumer/user accept this?” if it is sold to users, or “would this create issues down the road?” if the part is to be further processed or assembled.
However, there needs to be a checklist too. After all, the products were made based on an agreed-on specification, right? Does production conform to these specs? The typical approach is to use these specs as a checklist, to guide the control process.
Let’s take a product everyone is familiar with: a wristwatch. You can see a short video about a full inspection checklist of watches here.
Each of these tests might require specific training and equipment. Here is an example (how to test a watch’s accuracy):
What is Quality?
Quality has become one of the most important factors of consumers decision in selecting a product among competing products (services). This phenomenon is wide spread regardless of the fact whether the consumer is an individual organisation, retail store, or a military defense programme.
The quality of products / services can be evaluated in several ways. It is important to identify different dimensions of quality Garrin (1987) discusses eight components or dimensions of quality as follows.
- Performance (Will the product do intended job?)
- Reliability (How often does the product fail?)
- Durability (How long does the product last?)
- Serviceability (How easy is it to repair the products?)
- Aesthetics (How the product looks like?)
- Features (What does the product do?)
- Perceived Quality (What is the reputation of the company?)
- Conformance to standards (Is the product made exactly as the design indented?)
How to Implement Quality Project Management
Once you have an idea of the different concepts, the next step is to implement a project quality management plan. To do so, follow these three steps.
The plan will include these specifics as well as metrics for measuring the quality while managing the project. This should include a quality checklist to collect and organize the marks you need to hit during the project.
Quality assurance, according to the American Society for Quality (ASQ) is “the planned and systemic activities implemented in a quality system so that quality requirements for a product or service will be fulfilled.”
Use quality assurance to make sure your processes are in fact working towards making the project deliverables meet quality requirements. Two ways to accomplish this is by using a process checklist and a project audit.
Every process needs a policeman, so to speak, to make sure that the rules are being following and that the expected quality is being met. Some ways to ensure that the required quality of the deliverables is being achieved is through peer reviews and testing.
It’s essential to check the quality of the deliverables during the project management process in order to adjust the deliverables if they’re not meeting the standards that have been set. This can be done at the end of the project, but it’s not as efficient to redo rather than to readjust.
Getting familiar with the “AQL tables”, sometimes called “ANSI tables”
(Note: you can watch this in on Youtube by clicking here.)
1. The ‘lot size’
If you ordered different products, consider each product as a separate lot. (The quantity of each product is the lot size). If you ordered only one product, the lot size is the total batch quantity.
2. The inspection level
Different inspection levels will command different numbers of samples to inspect. In this article, we will stick to the so-called “level II” under “normal severity” and to single sampling plans.
3. The AQL limits
The AQL limits appropriate for your market. If your customers accept very few defects, you might want to set a lower AQL for both major and minor defects.
Some specialized quality inspection software will show all the numbers automatically, but it is good to understand how to read the tables.
There are basically two tables. The first one tells you which ‘code letter’ to use. Then, the code letter will give you the sample size and the maximum numbers of defects that can be accepted.
First table: sample size code letters
How to read this table?
If you follow my example, I assume your ‘lot size’ is comprised between 3,201 pcs and 10,000 pcs, and that your inspection level is ‘II’. Consequently, the code letter is “L”.
Second table: single sampling plans for level II inspection (normal severity)
How to read this table?
Our code letter is “L”, so you will have to draw 200 pcs randomly from the total lot size. Besides, I assume you have set your AQL at 2.5% for major defects and 4.0% for minor defects. Therefore, here are the limits: the products are accepted if NO MORE than 10 products with major defects AND NO MORE than 14 products with minor defects are found. For example, if you find 15 products with major defects and 12 products with minor defects, the products are refused. If you find 3 with major defects and 7 with minor defects, they are accepted.
Note: in quality inspections, the number of defective products is only one of the criteria. It is sometimes called “quality”, or “quality findings”. The other criteria are usually on the inspector’s checklist, which typically includes:
- Packaging conformity (barcodes, inner packing, cartons, shipping marks…).
- Product conformity (aspect, workmanship…). If all the products are in red color instead of orange, there is no need to count each sample as a defect. It makes more sense to refuse for product conformity.
- Specific tests defined in the inspection checklist (they might not be performed on all inspected samples if they are time-consuming or destructive).
If you really want to understand the concept of the AQL, you should spend about 20 minutes (total) watching this video on Youtube. Don’t forget to like and share it, please.