School of Engineering Machining video transcript.

Hello, my name is Dr. Richard Hood. I am a Lecturer in Mechanical Engineering and I am a machinist. And I would like to in this presentation and talk go through a few of the practical aspects and how machining fits in with a degree program at the University of Birmingham.

One of the first things that you will come across when you join is the integrated design project one and this is where we do as part of this module a design and build activity. You can see on the left-hand side, a simple design truss structure that the students are built and then they test. We have got to teach you a few things before you can do this. We have got to teach you the engineering drawings and the CAD design. You will do hand drawn engineering drawings and then you will move on to the computer software such as Solidworks.  

We will put you into teams and groups and then we will get you to build the structure that you have designed. You must try and build it to the tolerances that you have made, and you can see it is out of wood and this will be done in our laboratories at the University. And moving on from that will test your structure, then you can see an image of the test on the right-hand side. This is where the bridge is tested to destruction and you will have a very specific limit that you have got to achieve. If you do not achieve that, then you fail back part of the task. So, you starting to think like an engineer, and that will happen quite quickly when you get to university as an icebreaker activity.

Moving on, will also teach you workshop training. And here you can see a few images and some of our students doing hands on practical training in groups. So, what are they doing? They are learning how to use a lathe and every student will go through this learn the basics of how to use the live, how to use and then machine. How to do various operations and various inspection techniques on that. So that will be part of the end of the first year and the beginning of second year for students.

We will also cover some of the materials and manufacturing processes are some of the primary process like casting and forging and the reasons why they used the design issues. We will also cover welding fabrication and various aspects as back and then one of the key aspects and one of my favourite bits will look at design for machining.

Whenever you come to design anything if you want to make it. You have got to make it efficiently cost effectively reliably safely. And actually, a good quality component. So, you have got to understand some of the basics behind machining. So, this includes cutting tool designs. Why use radii, chamfers, and various other features. And you can see highlighted on this slide. A few aspects to this include steep walled structures on the left-hand side. This includes putting 90 degrees square corners on pockets. This is a very common feature that design engineering students often use. However, you still must have the intelligence and the ability to be able to use it and design things that can be made. Another couple of my favourites are flat bottomed drilled holes. The drills used for drilling holes in the wall do not have a flat bottom. You will often see students designing components that have flat bottom holes. When you come to turning a cutting tool that is used to make components but have an edge radius on it. And you need to make sure that the radius that you put on your part able to be made by those tools. That is a good thing as well that you have got to put radius on that because they are often stress concentrators as well.

We will do some project work. And here you can see an example of mechanical design a project work. So, you are putting all that design and the manufacturing theory into practice. This year we designed a single cylinder engine for a small unmanned aerial vehicle, and you can see example, the top right-hand corner and I send you one of my favourite OS engines. You can see one of the students designs below. They have done all the work they have gone through all the engineering design all the aspects, then they put that together. And you can see a cross section there. And then as part of that you have got to go through the material selection using computer software. Textbooks online materials, you have got to go through below sheets, and you have got to work out how are you going to make this

But to do that we use computer aided manufacturing software. And this is an example of the software we use now this is one of my favourites. This is my research area. The research feeds down into the teaching from this. This is something I have loved doing since I was a student at university when I learned how to use the software. We use industry standard software such as Autodesk Fusion 360, PowerMill, Solidworks and Siemens NX. I am going to illustrate this with a simple example. We have a square block. We are going to probe the component to determine the datums. And this is something that you have covered in the module. We are then going to look at machining across the top machining around the sides, the pockets and look at some five-axis machining. So here we go.

So, we are going to highlight the key aspects to begin with. So, the first one is the probing than the face milling across the top machine around the outside. The first pocket and machining. The second pocket requires a 3 + 2 axis positional move. The last two machining processes are full simultaneous five axis machining. And then finally inspection process. So, let us have the simulation now. So, the green is the block. It is about going in with probed with machining around the top. How I wish it were this quick to machine. We are doing the pocket machining, the other side and now on machining round and if you can see that cutting tool and it should slow down now. You can see that all five axes of the cutting tool are moving. So, what we are doing is we are using some of those design principles and the manufacturing to produce components that look good.

And then the final step would be doing the NC program. And you will learn about this as part of all our modules called Research and Application of Machining Processes. And you can see here I post process, the component. And I have looked through all the NC program. And one of my favourite things is to ask the students when we cover this material if they can remember what all the codes. So, G zero rapid, G 01 command feed, G 90 absolute and so on in this programming language. It is the same that is used for 3D printers for robots and for various other ones. And if you look closely, you can see a few of the X, Y & Z commands. You can also see the A, B and C's. Now, these are the angle of rotation, or in this case vector notation. So, maths is very important in manufacturing as well.

But we do not just do this in simulations we also do this in real life. And here is one from one of the machine tools that you saw me in at the start. This one is five axis simultaneous machining of a ceramic matrix composite blade made from exotic materials. So, you can see all the blade rotating and you can see the cutting tool spinning around that. So as part of these modules. You will also experience time in the labs, and this might be part of some of the modules that we cover, but also some of the final projects.

So, this is a DMG machining centre. This is a five-axis machining centre. So, x, y and Z axis on the head moves and then the table rotates and spins as well. The image on the left is showing the cutting tool rotating. What it is doing now is obtaining the length for the cutting tool. I am using a laser beam and breaking that laser beam to set the tool length. That machine is very special. In fact, what it does is, and if I show you the second image of it machining. So, there we are going back and forwards across a high-speed mill surface which is the component is made of hardened steel. The spindle is rotating at high speed. In this case 21,000 RPM. So, every minute. It does 21,000 revolutions. So, this is extremely fast typical car might be anywhere from 1000 to 4000 RPM. It is a very quick, but the tool holder is also moving up and down very small amplitude and you can see on the left, it says current amplitude 1.1 microns. So very small, but it is doing that very, very many thousands of times a second, it is doing to 31,100 hertz. So, every second, it moves up and down by one to two microns 31,000 times. So, what we are doing is we are doing ultrasonic assisted milling that, and this advanced machining process. There are very few machines of this type in country. And again, this is the research, and this is how it feeds back down through into the teaching

But we do not just do conventional machining have a cutting tool. We also do non-conventional machining processes. So, in this case this example is electrical discharge wire machining. So, what we are doing is we are machining a component. And it is a bit like if you are in a supermarket cutting cheese with a wire. However, instead of mechanical work we are using the electrical process. So, we have an electrical circuit bond was submerged under water, which is hence, you can see the bubbles. And the wire is creating a spark that jumps from the wire to the workpiece creates a mini explosion and removes the work piece of material. The best way I could describe this is it is a bit like creating the mini lightning storm. But instead of one strike of lightning every few seconds. They are doing many thousands of times a second. But these are advanced machining processes that you will get the technology and the theory and how they often used in industry.

We do not just do machining. We also look through rapid prototyping and will do things like 3D printing. So here we have a simulation that I am doing during lockdown. I have had a bit more time and I am reviewing. So, this one, is a simulation model of a model from a Saturn five rocket because I have got into rockets recently. So, I started look through those. You can see all the lines. Each one of those is a line of plastic that is moved ground and you can see how they have created it. So, we look at the processes behind the flows. And my time lapse if this being produced on my Ultimaker 3D printer. So, you will be able to use these to look at rapid prototyping components for Final Year and other projects on our bank and our suite of 3D printers. Most recently the 3D printers have been used to help with the COVID19 crisis in making of facemasks.

But it is not just the plastics. It is also the metals as well. And many of our research groups look at 3D printing of materials. And in this case, one of the machines that is within my laboratory. It is a hybrid machining centre. So, what we are doing is depositing material and, in this case, it is nickel-based superalloy, then we can remove it on the same machining centre. So, we have combined to processes in a hybrid process. We have got the additive way of building material and then we have got the subtractive when you are removing it. Again, as part of the modules you look through and study those

But it is not just all about the making components, but the checking and inspection is important as well. And you will cover things related to probing and inspection. So, this is looking at the accuracy, the tolerances that you have created. And you can see the image there of one of our coordinate measuring machines inspecting the bore. You will cover the basics. The most fundamental of these would be a ruler, all the way up to these coordinate measuring machines that are able to inspect complex features. We will also look at things like surface finishing surface roughness and work P surface integrity and functional performance of the components.

How does this fit in with my studies? Well, probably one of the best ways is to do an example of our formula student team. And this is a component we are looking at making and one of the students. As part of one of the modules on Machining looked at programming this and you can see this is all the student programming work. So, the top right hand in it shows the actual stress analysis for some mechanical design. Then they looked at how to machine it. What they have done is written a newspaper article for this. And I have to say I really do like the caption: Tool Fast, Tool Furious. I like my headlines for this part and then they have looked at the programming. And you can see this using PowerMill 2019. Then the actual manufacturing on the bottom right. So, they are going from initial concept doing the stress analysis, making sure it is fit in terms of both stress analysis and manufacturing then iterating nd then coming up with the finished components. So that is how it fits into your degree program.

Thank you very much.