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What Is The Role of Quality Control?

The role of Quality Control is generally misunderstood, even in professional circles, it is generally incorrectly used. This short course aims to provide a thorough understanding into what the role and benefits of Quality Control are.

What is the Role of Quality Control? So, Quality Control is important because it is about ensuring if something has been produced to the standards expected and is not defective. Combined with Quality Assurance, Quality Control is an important measure in producing quality.

What is Quality Control?

While Quality Assurance deals with the processes and the people involved in developing products. Quality Control assesses the final product produced to see whether it is acceptable. That is, has it been produced to the standard expected or does it fall short of this and is therefore defective.

Quality Control is about assessing whether what's produced is acceptable.

Consider a baker who bakes cakes. Once the cakes have been baked they can be tasted to check whether they taste as one would expect. If they taste as expected that is they are tasty then they have passed the Quality Control.

If on the other hand they don't taste as one would expect then the cakes are defective and have failed the Quality Control.

Quality Control vs Quality Assurance

When people talk about checking for defects and imply that this is part of Quality Assurance, they've confused Quality Assurance with Quality Control. As checking for defects is a Quality Control function.

"We need to Quality Assurance this product to see that it works as expected".

"If there are any faults with this product, they will come to light when we check it during Quality Assurance".

Both these quotes taken from the Quality Assurance section are incorrect because they should refer to Quality Control and not Quality Assurance.

Quality Assurance is about the process and the people involved in that process.

What does Quality Control (QC) do?

In certain industries a product has to be developed with certain regulations in mind. These regulations are geared to ensure high standards thus high quality. To reach these standards of high quality, rigorous Quality Control must be undertaken.

The commercial aviation industry is one where the regulations laid down by the Federal Air Administration (FAA) ensure that the level of Quality Control adopted by aircraft manufacturers must meet certain high standards.

It's understandable why such high standards are required by the FAA for aircraft manufacturers. The consequences of failure in an aircraft can be catastrophic, leading to likelihood of many fatalities.

The FAA regulations are designed to reduce the chances of aircraft failure and thus fatalities.

Likewise the Federal Drugs Administration (FDA) also impose very stringent regulations on the pharmaceutical industry. Pharmaceutical organisations have little choice but to adopt the FDA regulations.

Otherwise they will not be able to market their products in the USA and because the USA is the biggest market. The loss of profit from such a lucrative market simply cannot be ignored.

The level of Quality Control is proportional to the increased chances of injury or death from using a product.

When medicines are developed they have to undergo rigorous amounts of quality control which eventually leads to human trials. It can take years to bring a new medicine to the market and the costs involved easily run into many millions.

Like the FDA, the FAA also has to consider the increased chance of injury and fatalities when it comes to aircraft. As such the stringent mandatory imposition of strict FAA quality controls.

Both these regulatory authorities, the FAA and the FDA, do pose additional bureaucracy in the development of aviation and pharmaceutical products respectively.

However these regulations ensure that aviation and pharmaceutical products have undergone stringent levels of research, development and quality control. Leading to high quality medicines and airplanes which are safe to use.

The FDA and FAA regulations ultimately reduce important costs. Not the costs such as the development cost of a plane or a medicine but costs such as below which can be avoided by meeting regulatory demands:

 • Regulatory legal costs of a product failure, which include heavy fines;

 • Compensation costs from injuries and fatalities arising from using products that fail;

 • Loss of revenue due to bad publicity surrounding the failure of products;

 • Loss of license to trade in important markets.

Waste of Quality Control?

Quality Control can be hideously expensive and therefore it is prudent to reduce the amount of quality control used. Without impacting the quality of the product produced.

Consider a chocolate manufacturer who produces tens of thousands of chocolates each day. By adopting stringent quality control procedures the manufacturer would have to get every chocolate produced tasted. The tasting would spoil the chocolates and they would therefore be required to be thrown away.

Not only is this costly in terms of the number of chocolates being thrown away but the added expense of the people required to Quality Control the quality, that is taste the chocolates.

By only checking a selection of chocolates produced in each batch, the level of Quality Control undertaken is substantially reduced and only a very small amount of chocolates are spoilt by tasting. Yet an excellent standard of Quality Control can still be achieved by adopting this approach.

Quality Control is expensive however costs can be reduced without affecting overall product quality.

Why is Quality Control (QC) with Quality Assurance(QA) needed?

Whilst Quality Control and Quality Assurance are used in different ways, they can help each other out immensely.

It's not only the level of Quality Control that's important in reducing costs without affecting quality but the level and quality of the Quality Assurance used.

The better and more frequent use of Quality Assurance, the less need to adopt unnecessary levels of Quality Control. This ultimately leads to savings from reduced Quality Control.

Quality Assurance can reduce the Quality Control overhead.

How do you maintain Quality Control?

Consider a car engine manufacturer who outsources pistons from local suppliers. The Quality Control used to determine whether the engine has been built to a high quality standard, involves running a car with the new engine around a test track.

Every engine produced and fitted to the test car blows up when taken round the test track, thus leading the engine to be scrapped.

The reason is down to the piston heads having a circumference which is between 25 to 50 microns more than required. This leads to the piston heads rubbing against the piston walls in the engine and overheating, causing the engine to explode.

The cost to the engine manufacturer is immense as every engine produced fails Quality Control and has to be scrapped. Yet this loss can be stopped dead in its tracks, leading to the amount of engines blowing up reduced dramatically.

By adopting better Quality Assurance procedures and increasing the amount of Quality Assurance, the piston heads can be measured more accurately by either calibrating the equipment used more stringently or using more accurate equipment which is checked for accuracy more frequently.

Maybe there is no measurement of the piston heads currently undertaken, so this must be included in the Quality Assurance process.

By increasing the likelihood that pistons produced will be the required size, the level of failure, that is engines blowing up during Quality Control can be drastically reduced.

Better Quality Assurance reduces the level of failure from Quality Control.

The cost of improving Quality Assurance is far less than the costs of writing off products that fail Quality Control.

Many organisations under estimate the importance of having both Quality Assurance and Quality Control in their workplace. By adopting one or the other, they end up with additional costs leading to losses which are easily avoidable.

Both Quality Assurance and Quality Control are needed together as using one or the other can increase costs.

By getting Quality Assurance and Quality Control to work in unison, the quality of products produced increases as well as the potential for profit.

How can Quality Control be used to determine the quality of a product?.

By checking a product to see whether it is what is expected, can the quality of that product be determined. In the next section the Requirements, what is expected from a product, is discussed in detail.

Summary

 • Quality Control is checking what's produced is acceptable.

 • Too much Quality Control can be expensive therefore it is essential to determine the exact amount of Quality Control required.

 • Quality Assurance can reduce the level of Quality Control needed.

 • Ideally both Quality Assurance and Quality Control are needed to improve a products quality.

Understanding Requirements

The sole aim of developing quality products is to make sure that they are marketable. There's no point in building the safest, securest or most aesthetic product when it can't be sold because nobody wants it.

In a fiercely competitive marketplace, businesses need to be sure that their products fulfil customer expectations. Merely being functional, that is the product does what it was made for isn't going to guarantee sales.

Consider the Sinclair C5, as shown below. This vehicle hit the United Kingdom in 1986 and was designed to be a cost effective way of travelling on short journeys.

However the Sinclair C5 was ridiculed by many who drew attention to its safety aspect. Whilst the Sinclair C5 was functional, whereby it was able to take a person from one destination to another.

It wasn't what people wanted, as it was viewed as unsafe. Especially when lorry drivers commented on the difficulty of seeing the C5 from high up in their lorry cabs.

All in all the C5 was not only a financial disaster, it also made the C5's inventor, Clive Sinclair lose priceless credibility, which would take him years to recover.

The whole Sinclair C5 story proved that there is little point in trying to build a product, when it is unclear whether it is something which people actually want.

To avoid developing products that people don't want, an understanding of what people really do want needs to be developed.

If it's not what the customer wants, they won't buy it.

Blueprint

Some form of a blueprint needs to be developed which can be referenced to ensure that the products developed meet the customer expectations.

In a world of quality the term 'Requirements' is used to describe the blueprints of what a customer expects the products to be. These do not necessarily necessitate a set of drawings but can also encompass a set of goals, rules objectives and so on.

For example, an alarm clock manufacturer wants to develop a new alarm clock. Instead of just designing and building an alarm clock as the clock manufacturer sees fit.

The best approach would be to find out what the potential customer of the alarm clock would look for when deciding to purchase an alarm clock.

If the alarm clock manufacturer decided to design and build the alarm clock as they saw fit, with the assumption of it only being an alarm clock so any generic alarm clock design will suffice, they could end up with an alarm clock which simply wouldn't sell. As potential customers might find the alarm clock not meeting their needs. Customers may not like the design, the way the alarm clock works and so on.

By finding out what customers actually want from an alarm clock, the alarm clock manufacturer has a greater chance of designing and building an alarm clock which will sell.

This customer input into developing the alarm clock is the customer's requirements.

There's no point in building something that the customer doesn't like and subsequently doesn't want.

Many corporations are often guilty of overlooking customer needs and developing products on the assumption of them being appropriate for a particular market.

When these products are subsequently released, the corporations quickly realise through poor sales that these products are not what people actually want.

Types of Requirements

The Germans are renowned for the build quality of their cars with one manufacturer even making a reliability claim in their slogan.

The German cars meet a particular set of requirements laid down well before the car actually goes into production. These requirements help lay the basis of reliability which these manufacturers are world renowned for.

What would happen if the Germans built cars of the highest build quality but found it difficult to sell them in profitable numbers?

Sound difficult to believe?.

Well, one manufacturer designed and developed a car which was made to exceptionally high quality standards. Even so the car has failed to sell in profitable numbers leading to a loss which the manufacturer has had to write off.

The car in question's build quality and reliability are unprecedented. The level of equipment offered as standard and the performance of the car is second to none.

However the cars sales have made no serious impact on its rivals, with high depreciation being commonplace.

People who buy cars in the sector that this German manufacturer has developed their car for, are simply not willing to pay the same money that an executive Mercedes or BMW would command for their brand of car. Irrespective of its super build quality, luxurious specification and scintillating performance.

Whilst the car in question can be viewed as meeting the requirements set by the manufacturer, where a high quality vehicle has been assembled for the executive car sector. The requirements themselves could be viewed as being incomplete, whereby customer needs haven't been correctly identified.

Quality isn't just about building something and then checking to see whether the build quality is great.

There are different components needed to develop a comprehensive set of requirements. In part fulfilling these requirement components, isn't going to lead to marketable products.

In the case of this German manufacturer the requirements would have included a set of technical specifications and a set of goals in what the organisation hoped to achieve.

However, the important customer requirements were probably not detailed enough. Whilst they may have looked at what a customer demanded from a car in this sector on a technical level.

They probably fell short of checking to see whether the customer would be prepared to pay what the manufacturer thought was a realistic price for an executive car.

Furthermore, they could have established clearly in the requirements what a customer would be prepared to pay for an executive car.

By establishing what their customer required they could have built an executive car but for the lower end of the executive market. Allowing them to capitalise on customers from this market and potentially allowing them to become profitable with their new smaller executive car.

Requirements aren't just technical specifications but also include what a customer wants from a product.

Without a shadow of a doubt establishing clear requirements is the most important part of any project to design and develop products.

Requirements In Action

In the UK, vehicles that are over three years old are required by law to undergo a compulsory test to ensure that they are road worthy. (Interesting to note that there is no test in the USA where any vehicle irrespective of condition can be driven on the roads).

How are vehicles checked for road worthiness?.

Are they driven to see if they drive ok?.

Are brakes slammed on to see if the car stops?.

MOT

To ensure that that vehicle is road worthy, the Ministry of Transport, a government body has developed a series of checks where vehicles over three years old must meet to be classed as roadworthy. By meeting these checks the vehicles can be insured and taxed to be used on the roads.

The number of checks, the type of checks and the detail of the checks conducted form the MOT test. (MOT is an abbreviation of Ministry Of Transport).

These checks are the requirements of the MOT and the vehicle must be checked against these MOT requirements.

Vehicles that meet the checks, pass the MOT requirement and are allowed to be driven on the UK's roads. Vehicles that fail to meet the requirements set in the MOT are not allowed to be used unless any faults found are rectified. There are heavy penalties for using defective vehicles on UK roads including fines and driving license endorsements.

As an example, the MOT requirement for the safe level of tyre tread is 1.6mm. If the vehicle being tested has a tyre with less than this level of tread, the vehicle has failed to meet the minimum requirement level set for tyre tread and will subsequently fail the MOT test.

FMVSS

In the USA the National Highway Traffic Safety Administration issues Federal Motor Vehicle Safety Standards (FMVSS) and Regulations to which manufacturers of motor vehicle and equipment items must conform and certify compliance.

The FMVSS safety standards and regulations are requirements set by the National Highway Traffic Safety Administration. Vehicle manufacturers have to ensure that their motor vehicles and equipment meet these requirements.

"Each hydraulic brake hose assembly shall have permanently attached brake hose end fittings which are attached by deformation of the fitting about the hose by crimping or swaging." (Sec. 571.106 Standard No. 106; Brake hoses. S5.1 Construction. section [a])

The above excerpt defines a requirement for the vehicle brake hosing by the FMVSS. Failure to comply with this requirement could lead to prosecution and the imposition of restrictions on vehicle sale in the USA.

Both the MOT and the FMVSS provide a set of requirements which need to be adhered to.

Requirements Gathering and Specification

The UK driving license authority has started issuing plastic photo card licenses. These are designed to replace the paper based licenses that are still widely in circulation.

The plastic photo card license can be used anywhere in the world to hire a car EXCEPT in the UK. In the UK, the paper based license must be used in conjunction with the photo card license to hire a car. This seems strange because one would assume that because the photo card license is issued by the UK driving license authority, it would be perfectly acceptable in the UK.

However, the reason why hire organisations won't accept just the photo card license is down to there being no listing of driver convictions included on the photo card.

The paper license includes any driving convictions accrued including penalty points awarded.

Car hire organisations in the UK for insurance reasons, need to know the number of endorsements a potential hirer has. To ensure that the insurance supplied is not invalidated if the hirer is uninsurable due to too many driving endorsements.

Outside the UK, driving endorsements are not considered when a vehicle is hired so the photo card license is perfectly acceptable without the paper based driving license.

There simply is no space on the photo card license to list the endorsements. Space is taken up by the details of the driver including a photo and a list of the vehicles the driver is entitled to drive.

There is no additional space available to list any driving endorsements.

Why does the photo card license have no space for driving penalties?

Whatever appears on the licence does so because of the requirements laid down before the licence was developed.

The quality of these requirements ultimately affects the quality of the product delivered and the requirements for this licence were probably rather lacking.

During the requirements stage, greater effort should have been made on establishing the uses of this photo card licence and how it could eradicate the use of its paper equivalent.

Instead of using more space focusing on what type of vehicle entitlement a person has, this space could have been used more effectively.

The people involved with the requirements should have talked to different types of organisations that would be affected by the new licence type.

This 'gathering' of information from the different parties that could be affected by the licence is known as requirement gathering.

Ultimately the best person to gather requirements from would be the person who will use the product under development.

In this case, the requirement gathering should have taken into consideration how vehicle hire organisations would perceive the new licence.

Another excellent example of inappropriate requirements comes from the packaging industry, where the carton has become king at the expense of the glass bottle.

The initial designs of the carton included some designs that were not only very efficient to manufacture and cheap to make but were extremely cumbersome to open.

These milk cartons required a great degree of force to open and in many cases simply by opening with force needed, caused the contents to spill everywhere.

The older generation in particular simply didn't have the strength to open these cartons and as such complaints levied increased dramatically.

Quality Control

Why did they design such a difficult to use carton?.

The requirement gathering stage was probably not carried out or did not have enough input from people who would be using this product.

Or certain sectors of the community such as the elderly were simply not thought of as having a valid input in the requirement gathering stages.

Maybe the requirement stage merely focussed on developing cartons that were cheap to produce, leading to bigger profits.

In the end these types of cartons were replaced by more user friendly cartons, such as those with unscrewable tops, easy tear and easy cut cartons.

What was the cost of changing the cartons?.

 • Redesign of cartons;

 • Retooling the machines that make the cartons;

 • Loss of sales to competitors.

The cartons had to be redesigned which would have involved producing many designs and checking to see if potential customers were satisfied.

Once a design had been agreed, special tools had to be made to ensure that these cartons could be mass produced. Tooling as it's known is expensive.

When people get frustrated by something they go elsewhere. Carton manufacturers would have probably lost customers to competitors such as plastic bottle manufacturers.

These costs themselves would probably have run into millions. Compare that to the cost of gathering requirements from the sectors of the community such as the elderly that would have been affected by the design? Minimal costs would have been incurred.

That's why requirement gathering is so important, not only will it save on the costs associated with redesign and the loss of sales, but will ensure that the product is actually what people want.

If people get frustrated with a product they will go elsewhere.

Requirements - the big picture

Some organisations fail to even have any requirements at all, let alone complete a set of requirements. These organisations run the risk of developing products that customers don't really want or don't work as expected by customers. Leading to potential tend to develop products that fail?.

Requirements must be viewed as a giant jigsaw. When only all the individual pieces are put together is there a clear picture of the product to be developed.

With only a part finished jigsaw, the bigger picture can be unclear. As such the risk of developing a product which might not be marketable increases.

Checking Requirements

How can the requirements be checked to ensure they have been met?.

When a product has been produced, it must be checked against what was specified in the requirements to ensure that it has been developed as specified.

The checking of the product against its requirements is a form of quality control known as testing.

By testing it is not only possible to be sure that the requirements have been met but also reduce the impact of any issues that could arise.

The carton manufacturers who incurred additional costs to rectify their carton designs. For them it would have been more prudent to actually test some prototype designs with a number of potential customers who would use such cartons.

These potential customers could have been selected from different parts of the community. This could have helped in pointing out any particular customer type, such as the elderly, as having problems opening these cartons.

Measures could have then been taken to rectify the design to counteract the problems faced by the elderly. Thus saving the organisation millions of pounds from having to do it later.

Quality Control inspections are good way to ensure quality is maintained and any discrepancies are quickly determined.

Summary

 • Just because something is the safest, securest and most aesthetic doesn't mean it will sell.

 • Insufficient or incorrect requirements can be a costly exercise to rectify.

 • Requirements are needed to check against, to prove the quality of a product.

 • Requirement gathering is important to ensure that the design and build is something that someone will want.

 • Quality Control inspections at the start, during production, with random inspections can help in maintaining quality.

Related Questions:

What are the 4 types of Quality Control Inspections? There are four types of Quality Control inspections:

1. Pre-Production inspection. Before anything is developed or produced an inspection into the components, constituents, blueprints, requirements etc. needs to be done. This is to ensure there are no defects or issues which could result in the overall quality of production being affected.

2. Inspections during production to ascertain the quality during different parts of the production process are used. This can include a proof of concept to check the quality of expected production or stage by stage quality control inspection, allowing each stage to be verified as effective.

3. Random Inspection. Quality Control can be expensive especially if everything produced has to be tested. A final random inspection can help bring Quality Control down, by testing only a random production set instead of everything.

4. Customer Inspection. The customer can also provide some form of inspection by checking and using products and services. This can help in identifying faulty batches and potential deficits in production quality control systems.

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