What It Means To Be a Mechanical Engineer

A Summary of My 4-Year, £44’600 Masters Degree

Callum McIntyre
Torque

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Rear Spaceframe and Suspension Design of FSAE Car

I spent 4 years and £44’600 on my MEng in Mechanical Engineering at Cardiff University. I completed 32 exams, 4 extended projects, clocking over 1800 hours in the pursuit of increasing my knowledge and skills in engineering.

I’ve always enjoyed the puzzle of getting things to solve problems, both fixing them and creating them.

One of the ideas I employ to get through all of that studying is the Feynman Technique:

  1. Choose the concept you want to learn
  2. Pretend you are teaching it to a 5-year-old
  3. Identify gaps in your explanation, go back and fill them
  4. Review and simplify

The second step is the one that helps, try to explain it to someone with no prior knowledge. That’s the key to understanding, Thomas Mann agrees:

“Order and simplification are the first steps towards mastery of a subject” ― Thomas Mann

So that’s what I’m going to attempt to do today, boil all of that learning down to one post. Not in an attempt to trivialise it, but to solidify it for myself and help others understand what goes into making something at scale.

1. Definition

To effectively explain this, I need to define what a Mechanical Engineer does. Obviously, this varies from role to role, I consider myself a Design engineer, so will take that stand.

IMechE defines Mechanical Engineering as:

“Mechanical engineering is a diverse discipline that encompasses the teaching, practice and leadership of others in the development and application of scientific principles to mechanical systems. Mechanical engineering covers the ability to solve problems that deliver and optimise safe, sustainable and ethical solutions for the design, production and operation of devices, machines, structures, processes and systems involving mechanical elements. Mechanical Engineering frequently overlaps and/or combines with other engineering technologies to create multi-disciplinary projects/solutions.”

Complex, eh.

I put it like this:

“Mechanical Engineering is solving problems by specifying, designing and manufacturing solutions with minimal societal cost and maximum efficiency when completing it’s given task.”

I use the term ’societal cost’, as minimum manufacturing cost often isn’t the goal. There are often other constraints such as:

  1. The lifetime cost to the customer
  2. Wastage in Manufacturing
  3. Use of ethical materials
  4. Reliability
  5. Safety
Connection Rod Before and After Topology Optimisation — link

Often, great design comes down to reducing a component to the minimum required to meet the requirements. Here is an example of Topology Optimisation (reducing down the mass such that there is no material not carrying load). This results in a lighter, stronger and (arguably) prettier part.

The process of Mechanical Design often goes like this:

  1. Define the use and requirements of the part

Work out the loads that must be sustained

What are the operating environmental conditions?

Minimum life expectancy?

2. Design Solution

Ensuring actually manufacturable

Minimising the cost of production

Selection of material and manufacturing process

3. Analyse Solution

Use computer programs to understand if the part is strong enough

Are there things that can be taken away?

Could two parts be replaced by one?

4. Iterate 2 and 3 over and over

5. Specify Production Processes

Obviously this is a massive over-simplification but it shows the work-flow. Often this process can take many months.

My second point is that Engineers have to have a tight handle on uncertainty. We are making things with processes that are far from perfect, with materials that vary (in temp, material properties, corrosion etc) to fulfill constantly changing requirements.

Photo by Joseph Barrientos on Unsplash

Take the example of a bridge.

  • Are the material properties of the steel used constant? No.
  • Is the loading constant each hour, day, year? No.
  • Is the environment constant? Very much no.

Dr. AR Dykes puts it this way.

“Engineering is the art of modelling materials we do not wholly understand, into shapes we cannot precisely analyse so as to withstand forces we cannot properly assess, in such a way that the public has no reason to suspect the extent of our ignorance.”- Dr. AR Dykes

2. The Basics

Most of the first year is spent going over basic engineering practice, I will save you the time and summarise.

There are a number of key skills needed to complete the modules further on, as well as others that make you an effective team-member in an organisation.

1. Maths

A lot of time is dedicated to this, after all — most of the following 32 exams are going to be heavily maths focused. By that, I mean multiple 25 mark questions with the aim of calculating the solution to a mechanical, thermodynamic or dynamic problem. It can be intense.

Understanding of Integration and Differentiation, manipulation of complex formulae and documenting your process through a problem.

This is all stuff that is covered in A-Level maths, but taken further.

It’s not hard once you get your head out of the “I must get to the final answer in the shortest time possible” approach that school teaches you to do. It’s more “follow me through this line of thinking”.

2. Documenting Work

I was fortunate to learn these skills in my year in Industry at Renishaw. They, as pretty much all engineering firms, understand the importance of effective documentation.

“If it’s not documented — it never happened”

Work could be repeated unnecessarily without this and being a clear writer has massive benefits in your career.

Writing in past-tense as objectively and concisely as possible is tricky.

Scientific writing is an art, one that takes a long time to master (I’m still not there yet!) This is my dissertation on Machine Learning, probably my best piece of writing to date.

3. Understanding Units

It seems trivial, yes, but converting units is key. It’s also a big issue if you can’t do it effectively. Understanding the extremes is also important.

Eg. The difference between µm (10⁶m) and nm (10⁹m). Often confused, resulting in three orders of magnitude difference in the result. This lack of understanding will only multiply when talking about Ohms, Joules, Pascals etc.

3. Effective Design

This was the reason I am pursuing a career in Engineering, the delight of designing, manufacturing and seeing something you came up with.

I was taught a lot of this, again, at Renishaw. It shows the value of spending time in the industry — they teach you stuff that University can’t.

Anyone can come up with a design. But it takes a skilled engineer for that design to meet the multitude of requirements put on it.

The biggest omission that I saw from peer’s designs in the first year was the ability to make the damn thing.

1. Decide on the Manufacturing Process Before Design

I found I was able to design a part that was simpler, quicker and cheaper to make because I understood the process of machining.

Take the above image, a hole with square sides and corners. Very simple to make on the computer, suits the purpose.

Right, now go make that with a round cutting bit on a mill. Well, you can’t.

2. Understand Tolerances

Tolerance is a range of values that the parameter of a part needs to sit in for it to be accepted.

It’s easy to dismiss this and not understand the importance. Why would a part with a hole that is 2.95mm be thrown out and one that is 3.00mm be accepted? If a pin that is 2.95mm needs to fit in it, that’s why.

It comes down to this, it makes sure two parts always fit together and work as intended.

It took me a while to get this, but if every interaction between two parts is like this, then imagine the work that has gone into this in your car engine! Let alone the whole car.

3. Identify Manufacturing of Objects Around You

“Steal like an Artist” — Austin Kleon

Don’t be afraid to learn from others. A key for me was being able to look at an object — say the mug you’re holding.

  • “What material is it made from?”
  • “What process did they use to make it?”
  • “Was it made one-off, batch or continuously?”
  • “Has it had another finish?” eg. paint, anodising
Casting of a Mug — James Rice Design

The likelihood is that it was made by casting, pouring a liquid into a mould and letting it solidify. There is probably mould lines if you look carefully. Likely in a batch, with different colours paint (finishing process).

Now do this for everything, your phone is probably machined Aluminium or cast glass. Most consumer bottles are blown from a thermo-plastic, your headphones are probably injection moulded.

You can also start to understand material properties and their usual uses that way.

All of this builds your mental catalogue of options for making something, every time you are designing — you can flick through this catalogue and pick the best option for that thing.

4. Be Self-Critical

The biggest super-power in design is the ability to self-roast. You will only design great stuff if you hold yourself to the highest standards.

We’ve all been there — handed some work we are very proud of to a boss, senior, parent, teacher and had it torn apart. They bring up aspects you never even thought of. You get work back with red pen all over it or a list of the faults.

After that feedback, you can work on the mistakes and come back with something far better. It’s a nasty process but develops you and your work.

If you can do this to yourself, now that’s an advantage.

My rule:

Sit and stare at this work until you can list 10 potential faults — no matter how trivial. Then fix all of them that you can. Now repeat the process until you can’t find 5 faults — then you know it’s okay to show to the boss (or whoever).

By doing this, you impress others and are ahead — all the way.

5. Skills in Computational Design

CAD (Computer-Aided Design) is one of my favourite bits about the job. Sitting there and piecing a puzzle of how things fit together is fun. Conjuring up the most elegant or intuitive design possible.

I mainly work in Solidworks and Siemens NX, but there are loads of different CAD packages. Some extremely costly and some free.

I wish I could show you some of the designs I have worked on — but such is life.

Solidworks

Once a design is made, this can be either prototyped and tested or simulated in FEA (Finite Element Analysis). This is breaking a part down into minute sections and calculating the load on each section and how much it’s going to squash, bend or buckle.

FEA and Topology Optimisation of a Bracket — FE Training

Results look like this, red bits are most heavily loaded, green intermediate and blue not loaded. This shows how you can distil a part down to use much less material.

Big Learn #1

The toughest part of this is understanding the load that the part is going to be under in normal use. It takes days of calculations in some situations. I designed the spaceframe and suspension components on the Cardiff Formula Student car.

Cardiff Racing CR15

The calculations for loading for the suspension members (arms holding the wheels on) was 16 pages.

Calculations of member load in Good-Notes

It’s scruffy stuff but really tested my lateral thinking and all of the math practice that they taught us in the second and third years.

5. Specific Knowledge

I don’t mean to downplay this part, after all it is why you pay to go to Uni — to learn from experienced, knowledgeable people. But it doesn’t lend itself well to a summary.

I will attempt to over-simplify the topics I did study, though.

We learnt topics such as

  • Thermodynamics
  • Often about the challenges of heating liquids and gases to generate electricity
  • Heat Transfer of Materials
  • Similar to Thermodynamics but on a broader scale
  • Fluid Dynamics
  • How fluids (gases and liquids) react to different situations. It’s surprisingly counter-intuitive
  • Solid Mechanics
  • How materials deform and resist deformation
  • Energy Management
  • How firms can be more responsible with (often very high) energy usage
  • Quality and Reliability
  • How to design a system that is reliable and fulfils customer requirements
  • Condition Monitoring
  • Being able to predict when a machine is going to break, before it does.
  • Robotics
  • Understanding difficulties in producing reliable, accurate robots for use in manufacturing.
  • Automotive Power Transmission
  • Step by step of how to design a gearbox. How gears, lubricants, clutches work. (This was one of my favourites)
  • Computing
  • Coding in C++, Matlab and Python
  • Manufacturing Systems Design
  • How manufacturing environments work, how to design for them and how they can be improved.
  • Automotive Vehicle Design
  • Literally designing a Formula Student car from the ground-up with a team of 10 other students.
  • Integrated Building Design
  • Designing a hospital. Start to finish.

6. Biggest Learns

A summary of the biggest things I learnt in Engineering School.

  1. Everything has an equation, get good at equations and you can apply yourself to anything
  2. Materials, Fluids and Gases don’t behave how you expect them to
  3. Applying your learning to a real-life problem (like the FSAE car for me) makes you solidify your learning, triple check your work and allows the immense satisfaction of seeing your work in action.
  4. Bolts are bad. They are heavy, come loose all the time and rattle about, avoid them unless absolutely necessary.
  5. Additive Manufacturing (Incredibly Advanced 3D Printing) is going to change the world
  6. Artificial Intelligence is likely to be able to do my job in 50 years.
  7. I’m damn grateful I could do a year-long placement at Renishaw before Uni. It enabled me to apply all of the concepts taught to tangible real-world examples. It supercharged my learning.

Thanks so much if you got this far, let me know what you thought of this. Was it what you expected?

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Callum McIntyre
Torque
Writer for

Growing YouTube Channels, Full Time. Content Director at Driver61 and Driven Media. But, I also like nice things - so I talk about them.