Lesson video

Hello there, my name is Mrs. Dhami.

Thank you for joining me for your design and technology lesson today.

Now the big question for today is which wasting manufacturing processes are suitable for metals? Now if you've ever made anything in metals, please try and think back to that project and relate our learning to that today.

If you haven't, don't worry.

I've got some beautiful gifts to show you to guide you through your learning.

So, hard hats on.

Let's get cracking.

Our outcome for today is we will be able to explain and compare small-scale and industrial wasting processes.

We have four keywords today.

Wasting, which is removing material to shape or size a product.

Small-scale production, which is making one or a few products using hand tools or basic machines, just like a school workshop.

Industrial, which is higher-volume production using machines for speed, accuracy, and consistency.

And finally, CNC, which is an abbreviation for Computer Numerical Control, which basically means computer-controlled machining for precise cutting and shaping.

We have two learning cycles for our lesson today.

Small-scale wasting processes and then moving on to industrial wasting processes.

So let's get started with small scale.

A wasting process is a manufacturing method where material is removed to shape or finish a product.

This includes cutting, drilling, and sanding.

These processes are commonly used in both small-scale production and industrial settings.

Before wasting, the metal must be marked out.

Now I'd like you to pause the video and have a little think what tools could you use to mark out metal.

Come back to me when you've got a few ideas.

Okay, let's draw us back together and let's see whether some of your ideas match some of the ones I have included.

So I'm gonna start with a centre punch.

Now a centre punch is used to mark the centre for drilling, and it has a tip angle of about 90 degrees.

It means that you've got a nice little hole for that drill to centre into, to ensure an accurate hole with no movement from that drill.

Next up is a dot punch, which is very similar to a centre punch, but it has a tip angle of 60 degrees.

Therefore, it makes smaller and sharper marks, and these tend to be used more as reference points.

Lastly on this slide, we have dividers.

Now dividers do look a bit like a pair of compasses, and they can be used in a compass kind of way.

So dividers can be used to mark circles, they can be used to mark arcs, but they can also be used to mark accurate distances.

So a little bit like a marking gauge that you might use on a piece of timber.

You can scribe a line parallel to an edge with a pair of dividers.

It's a really useful tool.

We then have a steel rule used for measuring.

An engineer's square is used to create square edges and lines.

And with both of those, we tend to use a scribe.

Looks a little bit like a dentist tool, I always think.

So a scribe is used to mark lines, rather than using a pencil.

And it will actually indent the metal where perhaps you want it marked out for cutting.

Cutting tools are used as part of the wasting process to remove unwanted areas.

These small-scale production tools that I'm just about to show you can be operated manually and ensure control and precision.

So let's start off with the hacksaw.

Now a hacksaw is a hand tool used to cut metal with a toothed blade held in a rigid frame.

Now we use hacksaws to cut things like metal bars, rods, and tubing.

Next step is the junior hacksaw, which is just a smaller version of the hacksaw, and it's designed for cutting thinner metal section than the hacksaw.

Next step is the coping saw.

Now a coping saw has a thin blade that can be rotated easily to cut intricate shapes.

The blade can also be removed to cut internal shapes out too, which is great.

However, a little note, you must make sure that you get the right blade that is suitable for metal, because, of course, coping saws can be used on much softer materials too.

Next up is the piercing saw.

Now a piercing saw is very similar to a coping saw, but it holds a finer blade.

In fact, sometimes the blades are so fine, it's actually difficult to see the little teeth that are on it.

Now this makes it ideal for creating detailed jewellery, such as there is a little cufflink there if you look just underneath the blade.

That cufflink was actually my dad's and I used a piercing saw to cut out a circle from it, and then I deformed that circle into a necklace.

Hence, I made an upcycled product from a cufflink to a necklace.

However, with a piercing saw, the blade is so fine that you have to be careful not to break it.

And one thing that you can do with a piercing saw is you can put some wax onto the blade to help it glide through a little bit more easily, less chance of it getting stuck and less chance of it breaking.

Tin snips.

Now tin snips are hand tools used for cutting thin sheet metal, which is ideal for small, curved, or detailed cuts.

And as you can see in the picture, I've popped that pair of tin snips into a metalworking vice, just because it is so much easier to operate them if you only have to push down one of the handles as a lever, rather than trying to push both of them in.

It means you can get through slightly thicker sheet metal when you do that.

Next step is a guillotine.

Now a guillotine is used to cut straight clean lines in sheet metal with a heavy blade, and that really, really long handle acts as a brilliant lever, which cuts through the metal much, much easier than the tin snips.

Now a quick reference to industrial wasting processes here because there are also what we call industrial guillotines, which can cut much larger and much thicker sheets than are possible in a school workshop.

As we know, cutting tools are used to remove unwanted areas.

Now small-scale production tools can also be operated by power.

So we have an angle grinder.

Now an angle grinder is a handheld power tool used for cutting, grinding, and polishing metal, using rotating abrasive discs.

Next up is a band saw.

Now a band saw can cut metal, but one thing to be careful of, the dust collector must be changed when switching from timber to metal, as the metal can produce tiny sparks that can actually ignite that timber dust.

Therefore, that is why we tend to have one bandsaw in one room that is used with metal, and a different bandsaw, quite often in a different room, that is used with timber.

And that's why we don't mix up the metals on each of those, if you were ever wondering.

Time for a quick check-in.

Which tool would be appropriate for cutting a delicate piece of jewellery in small-scale production? A, we have the coping saw.

B, we have the hacksaw.

C, we have the piercing saw.

Have a think.

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

Well done if you got C.

The piercing saw is appropriate for cutting a delicate piece of jewellery.

Drilling is also a wasting process that makes holes in a material.

So we have a cordless power drill, which is used for drilling holes and driving screws.

Now the metal is usually held with a g-clamp or mole grips to stop it spinning around.

We then have a pillar drill.

Now as you may or may not know, a pillar drill is fixed to a base and used to make straight accurate holes.

Metal is normally held with a g-clamp or a machine vice.

So again, it doesn't spin.

Drill bits are cutting tools that attach to a drill to make holes in materials.

Cutting oil, and I'll put that word in purple, because cutting oil must be used when drilling metal.

So to reduce the amount of heat that is created from friction, and then it extends the bit life, meaning that it won't wear down as quickly or it won't snap.

So cutting oil is a really good idea.

We have twist bits, which drill smaller holes.

We have hole saws which create large circular holes in sheet metal or pipe.

And then we have cone drills.

Now a cone drill is a stepped, drill bit that gradually cuts larger holes in sheet or thin metals.

And you can see, as each step goes up, the diameter gets wider.

Which drill bit could create large circular holes in sheet metal or pipe? A, we have circular.

B, we have twist.

And C, we have cone.

Have a think.

Come back to me when you've got an idea.

Well done if you've got A.

It is the circular bit.

The circular drill bit creates large circular holes in sheet metal or pipe.

Filing and abrading is a wasting process that involves removing material to shape or smooth a piece.

Now a hand file, just like the ones in the images, is a tool with a metal surface covered in teeth.

Now the teeth might be teeny-tiny or they might be much bigger than teeny-tiny.

Now that all depends on how much you want to take off.

So the bigger the teeth, the more material it will remove.

The smaller, the teeny-tinier the teeth are, the less and the more smooth finish you will get.

So files are used to smooth or shape materials like timber, metal, or polymers by rubbing it back and forth.

Hand files come in different sizes and profiles.

So for example, triangular, round, flat, and half-round, which all depend on the shape of the material that you want to file, and the shape that you want to create.

The next few GIFs show different techniques, actually, on a polymer, and this is my technician demonstrating this for us today.

Now I haven't changed it to a metal because it's exactly the same process as with a polymer, but we just apply it to a metal.

So first up is cross filing.

Cross filing is when you move the file diagonally across the material using a back-and-forth motion to remove material quickly and shape the surface.

The next technique is called draw filing.

Now draw filing is when you hold the file with both hands and pull it along the length of the material to create a smooth, even finish.

This gets a much better finish than the cross filing.

Cross filing takes off more, draw filing takes off less and creates a smoother finish.

Sanding can also be done with power tools and machinery.

This speeds up the wasting process, especially if there is a lot of material to remove.

So a power sander is often used in small-scale production.

The abrasive pads are available in different grades, depending on what type of finish you require.

A belt sander can also remove more material in a shorter amount of time.

But just like I said with the bandsaw, the metal must not be sanded on a belt sander that also sands timber.

Because just like that bandsaw, the metal sparks can cause timber dust particles to ignite, which can be very dangerous.

So, check, are you using the right machine for sanding the right material? Emery cloth is a flexible abrasive material used to smooth, clean, or polish metal surfaces, making it ideal for removing rust or preparing metal for finishing.

Next up is wet and dry abrasive paper.

Now wet and dry is being demonstrated in the GIF on the left.

Wet and dry creates a very smooth finish.

And just as it says in the name, it can be used either wet with water or dry without water.

Using it with water reduces the heat and gives a really fine polish, which looks fab.

As we've just said, abrasive paper such as emery cloth or wet or dry can be used to smooth, shine, or clean surfaces.

Now they come in different grades, or otherwise known as grits, which tell you how rough or smooth it is.

The number corresponds to the size of the abrasive grit on the paper.

So the lower the number grade, the more rough it is, and it removes lots of material very quickly.

While medium grades are used for smoothing things out, and higher grades, so you can see we've got 2,000 at the one end.

Higher number grades are used for polishing.

So next time you use emery cloth or wet or dry, have a little look at what grit you are actually using.

Perhaps you might need to change it depending on what you are trying to achieve with the metal.

Next up is polishing.

Polishing can create a shiny and smooth final finish.

We have buffer machines, which is the rotating polishing tool used to quickly smooth and shine the surface of metals.

And we also have polishes.

So a fine abrasive polish can be used to remove any scratches and give a shiny finish.

And you can see that being demonstrated with a bit of old cloth onto a polymer, but the same applies with a metal.

Which grade of abrasive paper is smoothest and will give a fine finish? A, 150 grit, B, 800 grit, or C, 600 grit.

Have a think.

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

Well done if you've got B.

The higher the grit, the smoother and finer finish it will produce.

On to task A, part one, I'd like you to define the term wasting process in the context of manufacturing.

Two, I'd like you to explain how to create a shiny and smooth finish on a metal during small-scale production.

Three, I'd like you to explain one advantage and one disadvantage of using a power tool instead of a hand tool.

And lastly, part four, I'd like you to explain why both hand and power tools are used in small-scale production.

Good luck with your answers.

Come back to me when you've got some great ideas.

Let's take a little look at our answers.

Part one, I asked you to define the term wasting process in the context of manufacturing.

You could have a wasting process is a method of shaping or finishing a material by removing parts of it, such as cutting, drilling, or sanding.

Part two, I asked you to explain how to create a shiny and smooth finish on a metal during small-scale production.

You could have said cross filing followed by draw filing will create a smooth finish.

To make it smoother, you can then use wet and dry abrasive paper, increasing the grit each time.

To ensure a shine, a buffer could be used or fine abrasive polish.

Part three, I asked you to explain one advantage and one disadvantage of using a power tool instead of a hand tool.

You could have had power tools are faster and require less manual effort.

However, they can be more dangerous and require a power source.

Part four, explain why both hand and power tools are used in small-scale production.

You could have had hand and power tools are both used in small-scale production because they each have different strengths.

Hand tools allow for greater control, precision, and detail, while power tools help speed up tasks, cut through material more efficiently, and reduce physical effort.

On to learning cycle two, industrial wasting processes.

Industrial wasting processes require more heavy-duty machinery.

This is because speed, accuracy, and consistency are required for larger production runs.

CNC is one of our keywords today.

It stands for Computer Numerical Control, which means that some machinery can be controlled by a computer using code.

CNC machinery is often used in industry because it can cut complex and precise shapes repeatedly with minimal human intervention.

Now I imagine, lots of you might have access to a laser cutter in your schools.

However, I imagine that hardly any of you will have laser cutters that can cut through metal.

That's because they tend to be more used in industrial wasting processes.

So laser cutting metals uses a high-powered focused laser beam to melt or vaporise metal, producing clean and precise cuts.

It is ideal for thin detailed work.

Changing the power of the beam can engrave text or images.

And laser cutting is often used in industry for signs and engineering components.

Don't be fooled.

This isn't laser cutting.

Look really, really carefully.

Can you see little bits of water spurting out from the bit which is cutting? Yep.

So this is water jet cutting.

Water jet cutting is a CNC industrial wasting process commonly used to cut metal sheets and components.

It uses a high-pressure stream of water mixed with abrasive particles to precisely cut metals without causing heat damage or distortion.

Pretty amazing, eh? Don't be fooled again.

This isn't a laser cutter again.

This is actually a plasma cutter.

Now plasma cutting is a CNC industrial wasting process, often used to cut sheet metals.

It uses a high velocity jet of ionised gas, known as plasma, to melt and blow away metal, producing accurate cuts with minimal material waste.

I wonder whether your design and technology teacher has ever said to you, "Don't cut that bit out from there.

That's right in the middle.

Cut it on the edge." I bet that's happened to a fair few of you.

Now this is what we call careful placement, otherwise known as nesting of designs.

And this is basically us as teachers and businesses trying to reduce the amount of waste that we produce.

Let's look at this in a bit more detail.

Look at the six circles cut out on the left in comparison to the six circles in the picture on the right.

Now, let me highlight it in grey.

Can you see? The amount of waste is a lot smaller on the one on the right.

That's because the circles have been carefully nested so that rather than being directly underneath, then move slightly to the side.

This means they can move them up and move them closer, which therefore reduces the waste.

It is important to nest designs, especially in industrial wasting processes, to maximise material use, reduce waste, and increase cutting efficiency.

Time for a quick check-in.

Which attempt at nesting reduces the most amount of waste? Is it A, B, or C? Have a close inspection.

Come back to me when you've got an idea.

Well done if you've got B.

B's nesting reduces the most amount of waste.

Because if you can see in A, there are four triangles cut out.

B, there are eight.

C, there are six.

So B manages to get the most amount of triangles with the least amount of waste.

Great example of nesting.

Drilling large numbers of holes that are accurate is important when manufacturing products in bulk, for example, automotive chassis parts or structural steel components.

CNC drills can create many holes quickly and precisely by following a computer programme to match a digital design.

This reduces human error and guarantees consistency across batches.

CNC routing and milling are used in industry to create complex shapes that will be difficult or time-intensive to produce by hand.

Both machines follow computer instructions to move their cutting tool accurately along the X, Y, and Z axes, to cut and shape the material.

CNC routers are used for softer materials and usually operate across a wider surface area, whereas CNC milling is used for harder materials and offers more precision and depth along the Z-axis.

You can see a CNC router in action here.

So the tooling can be changed on CNC routers, depending on the angle required.

So you could have a tool that cuts straight cuts, but you could also change it so that it cuts bevelled cuts, which basically means it cuts at an angle.

A CNC lathe shapes metal by rotating the work piece while cutting tools remove material with high precision.

The metal is held securely in the chuck whilst it rotates for cutting.

Examples of products include aerospace turbine components and pipe fittings, and connectors.

CNC lathes use different tools and techniques to create a range of precise cuts.

Let's take a little look at some of those techniques.

We have facing, which is used to square off the end, which is normally done at the start.

We then have parting, which is used to remove a piece from the main work piece, and this is normally done at the end.

We have drilling for creating holes inside our piece.

We then have parallel turning, which reduces the diameter.

We then have knurling, which creates a lovely texture.

And then we have taper turning, which creates an angle on that piece of metal.

Industrial CNC blanking and piercing are sheet metal processes where shapes are either cut out, which we call blanking, or holes are punched through, which we call piercing, using a press and die for high-speed, accurate production.

Products include metal washers and cutlery.

Which of the following industrial processes rotates the metal when wasting? Is it A, blanking and piercing, B, laser cutting, C, water jet cutting, or D, lathe? Have a think.

Come back to me when you've got an idea.

Well done if you got lathe.

The lathe rotates the metal when wasting.

On to task B, part one, I'd like you to explain one advantage of using CNC machines in industrial production.

Part two, name two metal industrial wasting processes and describe their main function.

Three, why are industrial processes more suitable for higher volume production? And lastly, four, compare a small-scale production process to its industrial counterpart.

Give one example and explain the main difference.

Good luck.

Come back to me when you've got some great answers.

Part one, I asked you to explain one advantage of using CNC machines in industrial production.

You could have had CNC machines can cut and shape materials with high precision and consistency, allowing large batches of identical components to be manufactured efficiently.

Part two, I asked you to name two metal industrial wasting processes and describe their main function.

You might have chosen the CNC router, which cuts and shapes sheet material according to a computer programme.

And water jet cutting cuts metal sheets and components using a high-pressure stream of water mixed with abrasive particles to precisely cut metals without causing heat damage or distortion.

Part three, why are industrial processes more suitable for higher volume production? You might have said industrial machines, especially CNC, can produce large numbers of parts quickly, accurately, and with very little variation between them, which is ideal for higher volume production.

Part four, I asked you to compare a small-scale production process to its industrial counterpart.

Give one example and explain the main difference.

You might have chosen the hand drill versus the CNC drill.

And you might have said a hand drill is manually operated and less accurate, while CNC drill is computer-controlled, faster, more precise, and can produce large batches efficiently.

Well done with all your hard work on those.

This brings us to the end of our lesson today.

Let's summarise what we have found out.

Wasting involves removing material to shape or size a product.

Tools and machines remove material in small-scale production.

CNC stands for Computer Numerical Control, which means that some machinery can be controlled by a computer.

Larger machines remove material quickly, more accurately, and consistently at scale.

Well done with all of your hard work today and I hope to see you in another lesson soon.

Take good care.

Bye, bye, bye.