A few days ago I was discussing design with a friend of mine. We both work in the medical device world, and the subject of systems design came up. It's one thing to design a widget - - but it's another thing to design multiple widgets, which all have to come together to form a widget system... one that entails many materials, many functions, many joints, and various sub-assemblies which each need to perform a specific task in the system. So the question came up as to how to manage the design of complex systems, and my simple answer hearkened back to the days of Henry Ford - - make things modular.
Modular design is, for the most part, a method of designed a system as a series of almost-standalone assemblies or objects. Each of these can be built by themselves, tested by themselves, and stand on their own until the system is ready to accept them. This classic manufacturing method was employed religiously by Henry Ford, who revolutionized American manufacturing by introducing more efficient ways to build products, especially those with many complex parts and sub-assemblies.
The modular design method is simple. It involves separating a product (an assembly) into definable smaller sub-assemblies. Take for example a car. We can basically separate a car into sub-assemblies like the body, the engine, the transmission, and the wheels for instance. For each of these sub-assemblies, we have a list of parts in that sub-assembly - - the body might have seats, windows, doors, etc. And each of those parts are themselves sub-assemblies - - the door will have a handle, hinges, buttons for locks and window controls - well, you get the picture. Ultimately the car is a huge list of parts, each one standing on their own as a discrete item that can be made, measured, and tested.
Modular design has so many benefits to it, both from an economy standpoint and an efficiency standpoint.
First off, modular design saves you money, because it prevents damaged or failed parts from finding their way into a system, which will subsequently kill the system when it gets tested. A $30,000 car is useless if the engine will not run, and if that engine will not run because of a $2.00 hose that kinked, you've just lost a lot of money building that non-running car.
Secondly there is efficiency. Modular design means that we can now design and build in parallel. While one person is designing and testing the doors, another person is designing and testing the engine. It also means that when the doors and engines are done, they can be stacked in a warehouse, ready for use as finished sub-assemblies. This means that building the car is just a series of sub-assemblies that come together to become a system.
A third benefit not touched on involves manageability. Imagine writing a computer program end to end, with no breaks or subroutines. No try debugging that program - - where do you start? By breaking the program into modules and subroutine's, the programmer can track the program response, and fix whatever subroutine is not behaving well.
Modular design is the present and future of design. Making complex things, which tends to happen with technology, means that we need to use smarter and more manageable methods to keep tabs on complex products.
Think back to 1908 when Ford first built the Model T, where there were no computers and no spreadsheets to track all that went into building a car.
...If Henry Ford could do it, so can you.