Hi all. As many of you would know, I’m a qualified engineer. I have a Bachelor of Mechatronics Engineering from the University of Sydney, and I got first class honors and was awarded the University Medal which means a high distinction average.
But I’m sure a lot of people would say that an academic education is no replacement for practical experience. And despite having an academic education, and incidentally all our sales, support and development team are degree qualified engineers also, I would totally agree with this.
So rather than give you any theory that I learnt at university, I’m going to give you four points that I learnt. Most of these were just throwaway lines and not a big deal was made of them at the time, but they stuck with me so I thought I’d share them here.
Number 1 – Use things for their intended purpose
This one actually came from one of my classmates, Arturo Arrate. His father was an engineer specializing in industrial control systems. In a group assignment once, we were discussing selecting a particular part for the pretend thing we were designing. I don’t remember what it was, but I do remember that the thing that was designed specifically for the job was more expensive than the other option, which was designed to do something else, but we thought we might be able to get it to do the job we needed.
He said that his father told him something useful once, which was that if you’re in that situation where you have to choose, make sure you choose the one designed for that job, rather than the one you think should be able to do the job. Simply because until you’ve done that job before with the thing not designed to do it, you don’t know all the pitfalls, traps and other things you wouldn’t have thought of. These have already been identified and solved in the product designed for the job. So if you pick the generic product which you think should be able to be made to work, you’re going to end up facing problems you didn’t even know about and you’ll end up doing even more hacks to get around this which will introduce further problems. So this wasn’t a point from a lecturer, it was a point from a classmate… who was repeating it from his father who had decades of real-world experience…
Number 2 – Factor of Safety
This one came from my 3rd year stress analysis lecturer, Andrei Lozzi. In mechanical design, when designing a mechanical part you have to work out all the forces that act on the part, their magnitude and direction, and the stresses they create inside the part, to ensure that it’s going to meet the target lifetime of the product. The idea is to add in a factor of safety, which gets multiplied by the load to ensure that the design isn’t marginal, it has some safety margin. A typical mechanical factor of safety might be say 1.2 or 1.3, meaning it’s designed to be 20% or 30% stronger than it needs to be.
One thing he said was that if your design breaks, it won’t be because the factor of safety was 1.2 when it should have been 1.4. Because even at 1.0, it shouldn’t break. It’ll fail because the design didn’t match the reality. For example:
1) The part was made with incorrect material
2) Porosity in the weld or in casting
3) Weld was not done to the correct depth
4) You forgot a whole force entirely
We got to see this first hand; at the Formula SAE competition, one of the teams had very skinny, machined-down, uprights. I looked at them and thought, wow, they’ve done some hardcore modelling and are very confident in its accuracy! The next day, they had buckled horribly. The reason was they had designed it to handle the loading of the car going up and down and around corners, but they forgot the force transmitted to the upright by the brake caliper. It’s true that a larger factor of safety will be more forgiving of such mistakes, but then why even bother calculating it. As one of my mentors said once “Don’t calculate, overrate”!
Number 3 – Time value
Most workshops will already know this one because they charge either an hourly rate, or they work out a job’s cost based on the hours and their nominal hourly rate. This was from the same lecturer, Andrei Lozzi, in the stress analysis course. Our first assignment was to design a weld. By design a weld, I mean work out how deep the weld has to penetrate into the parent metal. If the load on the weld is very light, then you don’t need penetration to half the depth of the parent metal. But one thing he said was “If your boss ever catches you doing this, you’ll probably get in a lot of trouble”, by which he meant that unless you’re designing something that’s going to be welded and made a lot of times, for example stadium chairs or something like that, the cost of doing the weld so that the penetration plus the height of the weld above the parent is equal to the parent, compared to the cost of doing the minimum penetration, is so small that the cost of any time you spend trying to optimize it swamps the actual money that you would save.
Number 4 – Practical experience is an awesome help
In hands-on courses like engineering, they try to give good practical exercises to allow you to apply the theory and really understand it. But just like I’ve said in other videos, a 3 hour lab session is a drop in the bucket of the 10000 hours’ experience you need to master your craft. I was in the fortunate (well, yes I had opportunities that others didn’t, but I was prepared to make the most of them when others weren’t) position of being able to work as an engineer while studying. So a lot of what I was learning, I was able to apply very quickly. Furthermore, because I’d had electronics and programming as hobbies before I got to university, many of the courses were pretty straightforward because I’d already had a large amount of practical experience.
So the message from this last point is you have to start! If you listen to Shane T’s interview on Do It For A Living.net, he tells the story of how he fuel injected a supercharged lawnmower engine in his teens and that’s how he started to learn, as an example. Often old-timers complain about youths being lazy and asking “the internet” rather than doing things for themselves that would gain them practical experience. And I think part of that is just because we want to see people start early so that they can get enough hours in to master their craft.
So there you go, I picked this all up at uni, but it wasn’t in any specific course. Cheers!