Lesson video

Hi there everyone, and welcome to today's design and technology lesson.

My name is Mr. Booth.

It's great to have you here.

Today, we are looking at quality control methods in manufacturing.

This is part of your Technical Principles unit.

Today's outcome, I want you to be able to identify and explain different quality control methods to check that a product meets its specification.

Four key words for today.

The first one is quality control.

Checks made on a product before, during, and after its production, so it meets quality and safety standards.

The next is technical specification, a detailed description of a product's requirements and features.

We then have tolerance, the acceptable range of variation in a product's measurements, and finally standardized component.

A part that is made the same way every time, so it can be used in a range of products.

Three learning cycles today.

The first is all about understanding quality control.

So let's get started.

Quality control, or sometimes shortened to QC is the process of checking a product against a technical specification to ensure that they meet the required quality.

Every manufactured item should be measured, tested, and examined to confirm it conforms to its specification.

Quality control is an essential part of production because it helps prevent defective or unsafe products from reaching the customer.

A technical specification is a detailed description of the requirements that products are checked against.

It will be decided on before manufacturing takes place.

Quick check for understanding.

Which of the following best defines quality control? Is it A, creating new products? Is it B, checking products against standards, C, planning production, or D, advertising products.

Pause video now.

Have a go at this.

Come back to me when you've got your answer.

It is of course B: Checking products against standards.

Checking products against standards is vital because first of all, waste, you can catch mistakes early and then make amendments to your production to make sure those mistakes don't continue.

You can all also avoid costly reworks.

Safety, you are making reliable products and you also get consumer protection.

Very important when making products.

We have reputation.

You want your products to be high quality, so you get consumer satisfaction.

And of course we have the legal side of things as well.

You will avoid product recalls and also you have to make sure that you comply with standards and laws.

Quick check for understanding.

Which of the following is a direct result of poor quality? We have A, increased waste and rework.

B, faster production.

C, more advertising revenue and D, product recalls.

Pause the video now, have a go at this.

Come back to me when you've got your answer.

It is of course A, increased waste and rework and D, product recalls.

A technical specification defines the exact measurement a product must meet.

This might be size, color saturation, strength, all sorts of other aspects.

However, it's not always possible for every single product to be exactly the same.

This is where a tolerance is needed.

Now, even though all these metal cans are made from the same material using the same process in the same factory, they won't be completely identical.

A tolerance is the acceptable range of variation in a product's dimensions or properties.

Now, a tolerance is stated as a plus minus number that shows the minimum and maximum values.

Now if we use this metal rod as an example, the metal rod must be 10 millimeters in diameter.

A tolerance of plus or minus 0.

2 millimeters allows the rod to measure anywhere between 9.

8 millimeters and 10.

2 millimeters, and it will still meet the specification.

So let's have a check for understanding on that.

A bolt is specified to be 15 millimeters, plus or minus 0.

3 millimeters in diameter.

Which of the following measurements would still be acceptable? Is it A, 14.

6 millimeters? B, 14.

8 millimeters, C, 15.

4 millimeters, or D 15.

5 millimeters? Pause the video now.

Have a go at this.

Come back to me when you think you've got the answer.

It is of course 14.

8 millimeters, and that's because all the other answers sit outside that 0.

3 plus or minus millimeter diameter.

A standardized component is a part manufactured consistently to a specific standard, so it can be used across multiple products.

It helps maintain consistent quality and makes assembly easier.

Examples of this include screws, nuts and bolts, bottle caps, staples, and of course zips.

Quality controls in many industries, for example, in the food production, quality ensures products are correctly weighed and free from contamination.

Electronics components are checked to ensure they meet precise tolerances.

And of course, in textiles, fabrics are checked for color consistency and defects.

Now the check for understanding, which quality control method would be most suitable to ensuring car body panels align correctly during assembly? Is it A, strength testing the panel, B, weighing each panel, C, checking panel color consistency, or D, visual inspection of the panels during fitting.

Pause the video now have a go at this.

Come back to me when you've got your answer.

It is of course D, visual inspections of the panel during fitting.

Your first task.

First, I want you to define quality control and explain two reasons why it is important.

Secondly, why are standardized components important in manufacturing? Give one example.

A manufacturer produces acrylic rods with a technical specification of 50 millimeters plus or minus three millimeters in length.

One rod measures 49.

6 millimeters.

Does this rod meet the tolerance? I want you to explain your reasoning.

Pause the video now, have a go at this task and come back to me when you've got your answer.

Let's have a look at some answers.

So first of all, I wanted you to define quality control and explain two reasons why it is important.

Well, quality control is the process of checking products against technical specifications to ensure they meet the required quality standards.

It's important because it reduces waste and rework, and it ensures products are safe and reliable for customers.

Next, why are standardized components important in manufacturing and give one example.

Standardized components ensure consistent quality and simplified assembly.

For example, using identical screws in furniture production allows parts to fit together correctly every single time.

Next, a manufacturer produces acrylic rods with a technical specification of 50 millimeters, plus or minus 0.

3 millimeters in length.

One rod measures 49.

6 millimeters.

Does this rod meet the tolerance? Well, of course, no, the rod does not meet the tolerance, and this is because the acceptable range is 49.

7 millimeters to 50.

3 millimeters.

And since 49.

6 millimeters is outside this range, the rod would of course fail quality control checks.

Well done.

Onto our second learning cycle.

Quality control methods.

Quality control is when checks are made on a product before, during, and after its production, so it meets quality standards and safety standards.

Manufacturers use a range of methods to check whether products meet their technical specifications.

So let's have a look at some of these.

First of all, we have visual inspections.

These are one of the simplest forms of quality control, and this simply means checking products by sight for surface defects such as scratches, dents, misalignment, poor finishing, or color mismatches.

Although quick and low cost, the problem with visual inspections is that you can miss hidden faults and it relies on the skill of the inspector.

As you can see in this watch, we have some faults in the manufacturing, where some of the hands have come loose.

That would be easy to miss.

Quick check for understanding.

Which of the following would not usually be detected by a visual inspection? A, scratches B, printing inconsistencies, C, internal cracks, D, misalignment of parts.

Pause the video now, have a go at this and come back to me when you've got your answer.

It is of course internal cracks.

Well done.

Manufacturers use tools and equipment to measure products against the technical specification and tolerances.

These methods provide greater accuracy than visual checks alone.

Different tools are chosen depending on the material, the product, and the level of precision required when carrying out those checks.

One you might have heard of are go, no-go gauges.

And these provide a quick pass or fail test.

If the product fits into the go side and not into the no-go side, it meets the tolerance.

And here we have an example of one.

So this plug gauge has a 12.

6 millimeter as its optimum size, so that would be go.

12.

9 millimeters is the upper limit, which is no-go.

And you can actually see here they even color code it to make it even easier.

Scales and balances check whether products are the correct weight, which is especially important where consistency matters such as in packaging or in components.

Quick check for understanding.

Why are go no-go gauges useful in production? A, they give precise measurements in millimeters.

B, they provide a quick pass fail check.

C, they reduce the need for tolerances.

D, they can measure color consistently.

Pause video now, have a go at this.

Come back to me when you've answered.

It is of course B.

They provide a quick pass/fail check.

Some quality checks require very high levels of accuracy.

Vernier calipers or digital Vernier calipers precisely measure internal external dimensions and depth.

We can also use micrometers.

Now they measure very small thicknesses or diameters accurately.

And here we have one that measures the outside, one that measures the inside and one that measures depth.

We also have laser measuring tools.

Now these can take non-contact measurements, which is useful for delicate or complex parts.

They're also very accurate.

In industries such as packaging, printing, and textiles, color must match the brand specification.

Tools like a densitometer or a digital color meter check that printed colors are consistent across batches, ensuring brand identity is maintained.

So here you can see a densitometer and it's measuring the darkness of a material.

And here we have a digital color meter, which will measure what color something is and how bright it looks.

Check for understanding.

Why is color measurement for packaging an important part of quality control? A, it reduces material waste.

B, it ensures products fit together correctly.

C, it ensures packaging is strong enough.

D, it checks consistency with brand identity.

Pause the video now.

Come back to me when you've answered.

It is of course D: It checks consistency with brand identity.

Very important in packaging.

Instead of checking every single product, manufacturers might use something called sampling.

What they will do is they will select a small batch of products.

This saves time and money, but it also introduces a risk 'cause of course, some defective products might make it through production and reach customers.

This is often used in continuous production where we make things like tin cans or glass bottles.

What is a disadvantage of batch sampling? Here we have a quick check.

Is it A? It's too time consuming.

B, it may miss some defective items. C, it prevents standardization or D, it cannot be applied to large scale production.

Pause video now.

Have a go at this.

Come back to me when you've got your answers.

It is of course B.

It may miss some defective items. Functional tests check whether a product performs as intended.

For example, testing a chair to see if it supports weight or ensuring a zip opens and close smoothly.

This ensures the product is fit for purpose.

Here we have example of testing a mattress's firmness.

You can see that the red feeler arm is touching the mattress, which means that this mattress actually fails the test.

In this one, you can see it's passed.

The feeler arm is not touching, and you can see in the spirit level the bubble is in the middle.

So therefore it has passed the quality control.

Destructive testing, this is where the product is tested to the point of failure.

The most notable example of this is crash testing cars or bending beams until they break.

It gives very accurate information, but of course it wastes the tested product.

You can't sell it afterwards.

Drop tests are often carried out on smartphones to measure their strength and durability.

We also have non-destructive testing.

This is where the product is tested without damage using ultrasound, x-ray or laser inspection, or sometimes a mixture of all three.

This is often used with turbine blades in aircraft and also windscreens.

And this allows the product to be sold or used afterwards.

You can see here we're doing an x-ray check to check for defects in fluorescent light bulbs.

Modern factories often use automated inspection systems for quality control to compare products against their technical specifications.

So of course we have visual systems. Cameras can capture images or products and software will check defects such as scratches or imperfections.

We have laser scanning, so 3D laser scanners measure dimensions with extreme accuracy assuring parts are within tolerance once again, checking them against the specification.

We can of course have sensors as well, so machines can check weights, thicknesses, or color automatically.

They can even then remove those products from the production line automatically as well.

Automated inspection is faster and more reliable than human checks.

Computers can detect tiny variations that the human I just simply would miss, and they can also inspect every product on a production line without slowing down manufacturing.

However, automated inspection is very expensive to install and maintain.

Here you can see an automated inspection system for making chips, but it's great for this high volume manufacturing because of its speed and accuracy and also it prevents contamination.

Quick check for understanding.

Why are automated inspection systems used in modern manufacturing? A, they can check products quickly and consistently against the technical specification.

B, they add value to the product.

C, they make production cheaper by avoiding all testing.

D, they reduce the need for any training of staff.

Pause the video now.

Have a go at this.

Come back to me when you've got your answer.

It is of course A, they can check products quickly and consistently against the technical specification.

We're onto your next task, task B.

I want you to give one advantage and one disadvantage of using sampling instead of testing every product in a batch.

I then want you to explain the difference between destructive testing and non-destructive testing and give one product example for each.

Finally, compare the use of visual inspection and automated inspection systems as quality control methods.

Your answer should include advantages and disadvantages of both.

Pause the video now.

Have a go at this task.

Come back to me when you've completed it.

Let's have a look at some sample answers.

So first of all, I wanted you to give one advantage and one disadvantage of using sampling instead of testing every product in a batch.

Sampling saves time and money because not every product has to be tested.

However, faulty products may not be selected in the sample and could reach the customer.

Next, explain the difference between destructive testing and non-destructive testing.

And give one product example for each.

Destructive testing involves testing a product until it fails.

For example, crash testing a car.

Non-destructive testing checks products without damaging them.

For example, ultrasonic scanning of aircraft components.

I then wanted you to compare the use of visual inspection and automated inspection systems as quality control methods.

Your answers should include advantages and disadvantages of both.

Well, visual inspection is quick and inexpensive, and can identify the obvious faults such as scratches, dents, or poor finishing.

However, it relies on the skill of the inspector and it can miss small or hidden defects.

Automated inspection systems use cameras, lasers, or sensors to inspect every item quickly, consistently, and with greater accuracy than human inspection.

However, they are very expensive to install and maintain and they require technical expertise to operate.

We're now onto our final learning cycle, applying and evaluating quality control methods.

Not every quality control method is suitable for every situation.

When deciding which method to use, manufacturers must consider a few things, speed versus accuracy.

A go, no-go gauge is fast, but less precise than a micrometer.

Cost versus benefit.

Advanced laser scanners are accurate, but very expensive.

Waste, destructive testing provides useful data, but the tested products cannot be sold.

Reliability, batch sampling saves time, but risks missing faulty items. Quick check for understanding.

Why might a company choose a go, no-go gauge instead of a laser scanner? A, it removes the need for tolerances.

B, it's cheaper and quicker to use.

C, it provides more precise results.

D, it guarantees 100% accuracy.

Pause the video now.

Have a go at this.

Come back to me when you've got your answer.

It is of course B.

It's cheaper and quicker to use.

We're now gonna look at different industries and what kind of quality control methods they may select to use.

So let's start with the automotive industry.

Laser measuring tools ensure panels and components fit precisely.

Destructive testing is used in crash tests to check safety and durability, and in fact, they have to do that by law and automated inspection systems also common check for welds, panel alignment and paint finishes.

Check for understanding, why is destructive testing essential in the automotive industry? A, it reduces production costs.

B, it's cheaper than non-destructive testing.

C, it checks whether cars look appealing.

D, it ensures safety by testing components to failure.

Pause the video now.

Have a go at this.

Come back to me when you've got your answers.

It is of course D.

It ensures safety by testing components to failure.

Let's look at the construction industry now.

Non-destructive testing is used to check the strength of materials like steel beams and concrete without damaging them.

Of course, you can't test concrete until you've made it.

So what you would do is you would obviously make your wall in this case and then you can test it afterwards to make sure it's still got the strength you need.

Standardized components such as bolts and fittings.

Ensure structural safety and reliability because let's remember, these standardized components will also go through their own quality control checks.

Quick check for understanding.

Which quality control method is most useful for checking concrete structures without causing damage? A, sampling B, visual inspection, C, non-destructive testing, D, destructive testing.

Pause the video now, have a go at this.

Come back to me when you've got your answers.

It is of course non-destructive testing.

In the medical industry, automated inspection systems are used to check syringes and implants against technical specifications.

Also, functional testing is used to ensure devices like blood sugar or pressure monitors perform as they are intended.

Check for understanding, why is batch sampling risky for medical devices? A, it takes too long.

B, defect items could harm patients if they are missed.

C, it's too expensive.

D, it requires specialist training.

Pause the video now, have a go at this and come back to me when you've got your answer.

Well, it is of course B.

Defective items could harm patients if they are missed, which is often why sampling isn't used for these products.

We're now onto your final task task C.

I want you to explain one advantage and one disadvantage of using destructive testing in the automotive industry.

A construction company needs to check whether steel beams meet their strength requirements, discuss whether destructive or non-destructive tests would be more appropriate.

And finally, I want you to evaluate the use of automated inspection systems compared with visual inspection in high volume manufacturing.

Pause the video now, have a go at this task and come back to me when you've completed it.

Let's have a look at some sample answers.

So first of all, I wanted you to explain one advantage and one disadvantage of using destructive tests in the automotive industry.

Well, it shows how a vehicle behaves in a real crash, ensuring safety, however the vehicle tested cannot be sold, which increases costs.

Next, a construction company needs to check whether steel beams meet their strength requirements, discuss whether destructive or non-destructive testing would be more appropriate.

Non-destructive testing allows the beams to be checked for faults such as cracks or weaknesses without damaging them.

Destructive testing would give accurate results but would waste the beam, which is expensive and impractical in construction.

Finally, I wanted you to evaluate the use of automated inspection systems compared with visual inspection in high volume manufacturing.

Well, visual inspection is cheap and simple, but relies on human judgment and can miss small faults.

Automated inspection systems use cameras and sensors to check every product quickly and accurately though they are expensive and need skilled operators.

Overall automated systems are better for high volume, high precision work while visual checks suit simple, low cost products.

And that brings us to the end of today's lesson.

Let's have a quick summary.

Quality control checks products against the technical specification.

Quality control ensures products meet required tolerances.

Standardized components ensure consistent quality across products.

Methods includes visual inspection, measuring tools and functional testing.

Automated systems check products quickly and accurately.

Choosing quality control methods, balances speed, cost and waste.

Well done today.

You've all been fantastic.

I look forward to seeing you next time.

Goodbye.