Factories to me are like software to software engineers.
* Complicated systems with certain requirements to meet (transactions/second | units/day)
* Uptime requirements (99.99% for some web services | 70% is great for really old equipment)
* Budget requirements (dev time cost | cost per unit)
* Unrealistic deliverables (seamless launch on a production server without testing in that specific environment | 110% capacity scheduled and ignoring the preventative maintenance outages that were scheduled)
* Changing requirements (Customer changed their mind on <major feature> | Marketing wants to launch the new product in 2 weeks rather than 3)
* A variety of demands and sub-optimal conditions (crappy server to deploy on | factory equipment from the 1940's)
* Appearance of simplicity to the uninformed ("UX mockup is done, so the software will be in production next week!" | "Just increase inventory levels and we wouldn't stock out our customers.")
* People with different incentives pulling for different objectives (Non-technical manager doesn't get why code isn't done on time | Production is pissed that Quality won't release a set of parts)
At the end of the day, looking at and understanding the larger system is what makes an industrial engineer or software engineer effective. At first glance it may not seem like doing <x> will make a big difference, but <x> can either be a simple fix that was overlooked earlier or it can mean undoing hundreds of hours of work. That's true in programming and on the factory floor.
# Other IE Things
ERGONOMICS: Haven't even mentioned that yet. Workplace injuries often fall into an IE/mfg eng. role as well. Rather than doing the exact same thing all day long, it's not uncommon to switch jobs with a coworker after 4 hours. This gives the muscles required for Job #1 a chance to recover and repair before they're damaged too much. Doing the same thing all day can lead to repetitive stress injuries (and is simply more boring).
Fixing Drawings: Lots of times the prints (part drawings) will have assumed tolerances such as +/- 0.01" for lengths. If the designer simply marks "18 inches", it must be 17.99-18.01". To achieve that on cutting stock material to length will require some pretty good measuring. If it would function fine at +/- 0.5", the cost of production just decreased significantly. Throw it into the bandsaw and quickly confirm with a tape measure and move on. Tolerances should be as loose as possible to still allow for full functionality of the part/assembly. Going any tighter than required drives the cost up very fast. This is a common battle between manufacturing engineers and mechanical/design engineers. At Iowa State the mechanical engineers were briefly introduced to Geometric Dimensioning and Tolerancing (GD&T) around sophomore year while the IE's had ~1/3 of a class focused on it. There are thousands of ME's who know nothing at all about tolerancing and are making products more expensive because of it. I'm kinda passionate about this one. Tons of stuff has horrible tolerances
Order Quantities: How many of each part should be delivered from suppliers? What's the economic order quantity? [1] We have formulas for some of the more straightforward questions in this area, but things can get more dicey with something as simple as a bulk order discount. Is it worth ordering a bit more to get a price break considering the additional warehouse space required? That little modification makes the decision much more difficult.
Part Presentation: How will everything be presented to the assemblers on the assembly line? Just the orientation of a part can have a big impact on how fast something can be assembled.
Assembly Assistance: How will the parts be held during assembly? What can be done to make the assembly faster? Not threading the entire length of the bolt, tapering holes so screws drop in almost effortlessly, jigs to hold the parts, dummy-proofed systems so the parts physically cannot be assembled incorrectly, reductions in the number of pieces, etc.
Reducing Waste: In lean manufacturing, there are 7 wastes: Overproduction, Inventory, Waiting, Motion, Transportation, Rework, and Over Processing. [2] Reducing or eliminating these has a substantial impact on profitability. If you have a 5% profit margin on widgets and you scrap a widget, you just wiped out the profit from 19 good widgets. Bad quality is expensive.
Project justification: We have $40 million available for CapEx. What should we do with it? We have a set of possible projects, what combination will get us furthest towards our overall goals? What's the payback time on the investments? If it's more than 2 years, it won't get approved in most companies. The 2 year ballpark changes based on how conservative the company is and the overall economy, sometimes dropping to a matter of a few months for full payback during recessions. These calculations involve working with finance and accounting to determine the value of investments taking into account wage rates, overhead, cost of the project, and the discounted cash flows going forward.
Optimization: Is the way we're doing things mathematically optimal? As my professor put it, you want to run your system optimizing on profit so that a competitor cannot come into the market, get all the same suppliers and deals, then beat you on profit or cost to the customer. Pages 3-14 of this presentation demonstrate the introduction to optimization accompanying his explanation of why it matters. [3] Additional sets of slides available at [4]
Produce in-house or outsource?: Outsourcing can sometimes mean a company which specializes in that particular type of part will make it. This can reduce cost because your company doesn't have to be the subject matter expert on everything. It's also harder to get a response from a vendor regarding a quality issue than someone inside your same company.
# The "E" in IE
Finally, to refute an argument I've heard too often, IE's (at least from Iowa State) are not basically business majors. I had more practical business info thrown at me than an Aerospace or Mechanical engineer typically would, but the coursework is largely similar to other engineering programs.
There are programs I know of in which IE's are glorified business majors, but the Iowa State program is "Industrial and Manufacturing Systems Engineering". ISU and Penn State in particular have a strong manufacturing emphasis. During undergrad, ISU IE's took Calc 1-3, DiffEq with laplace transforms, thermo 1, chem 1 (no lab), physics 1 and 2, materials engineering 1, and statics. Beyond that the engineering majors typically diverge into major-specific content.
For us, that includes classes on optimization, ergonomics, engineering economics, material removal processes (machining mostly), solidification processes (casting and injection molding with an awesome hands-on lab), engineering drawings, production systems (order quantities and stuff like that), stochastic systems (includes some factory simulation), quality assurance, and a rough 200 level calc-based statistics class.
I hope putting the info out there a bit more will make people more aware of the breadth of what we work on. I'm more than happy to answer any other manufacturing or IE questions.
[1] https://en.wikipedia.org/wiki/Economic_order_quantity
[2] http://leanmanufacturingtools.org/wp-content/uploads/2013/06...
[3] https://drive.google.com/file/d/0B4afywTc7GYfMGdoYm5ZcTdIU2s...