Fluids, heat transfer, thermodynamics, kinetics--the list of things that I learned in school goes on and on, and I am grateful for all of that knowledge. It makes me the stellar employee that I am today, but there are a few things that I have learned in the real world that I really wish they would have clued me in on before releasing me out into the world.
Theory Doesn't Always Work
The joke in our department was always that chemical engineers are the best guessers in the world; at least I thought it was a joke until I started working for a polyurethane manufacturer. Based on the process, and the way things work in textbooks, if I wanted foam with certain properties, I just adjusted the amounts and types of chemicals used in order to produce perfect foam that cured in x amount of hours and was off to the customer in perfect condition. I couldn't have been more wrong. What ends up happening is you set up the process to the last successful attempt that you had, from there, it is guess and check based on how you think the foam looks. It is entirely subjective.
So why did I spend thousands of dollars learning theoretical equations that got thrown out on day one? It gives you a good baseline to guess from, in theory at least. The joys of entering a process that already exists is that someone else already did all of the theoretical work for you, you get to guess and check to try to improve on the process that is already in existence.
Quality Is Subjective
I took a course in plant management that taught us how to calculate tolerances and how to identify defects, etc. What this course kindly forgot to mention to me was that a ton of money can be saved just by asking the customer what they are using the product for. A customer gives you specs for what they want the product to be like, but in reality, they might not need tolerances to be as tight as you are making them.
My advice is that if you are having high scrap and reworking costs on a product, take five or six parts that may or may not be defects and ask the person working quality on the line their opinion, then take those parts to the customer and ask their opinion. Often the customer will see fewer defects than the person working quality on the line. The number-one best way to establish quality standards on a part for a specific customer is to completely understand what that customer is looking for and deliver that to the customer.
The Engineer Is NOT Always Right
On paper, maybe the engineer is always right, but there is no mathematical constant to throw into an equation to take into account the unwillingness of employees to implement a new process.
Lean manufacturing is a really hot issue right now, and looking at it from an engineering perspective, it really makes sense. There is one crucial step in lean manufacturing that no one ever teaches you. The greatest secret in any manufacturing facility is to talk to the people on the line. Understand what they are doing and what parts of the process they feel needs improvement. If the people who are actually working the line do not see need for improvement, or do not understand why you are making changes, they have the ability to make implementation of a new process very difficult. People do not fit nicely into equations, so it is always best to have a good relationship with the people who work for you.
There is so much more to being an engineer in the real world than simply numbers and design. Soft skills are something that school just can't teach you, but they are crucial in the real world.