Design for Manufacturability.

While playing with the mini-lathe, mini-mill and 3d printer, I came across an interesting concept called design for manufacturability.

The essence of the problem is this: it’s not enough to design a thing: a computer, a hammer, a pencil, a power drill. You also need to design the object so that it can be manufactured: so that it can be moulded, milled, and assembled in an efficient way.

Here’s the thing: with every process used to make a thing, there are limits on the shape, size, and materials that are used in that manufacturing process. For example, consider plastic injected moulding. Typically two mold halves are pressed together, plastic is injected into the mold, the material cools, and the halves are separated and the molded part is pushed out.

Well, there are a couple of limits on what you can create using plastic injected molding. For example, you must use plastic. You also must design the part in such a way so that the part can slide out of the mold. This means the part must be, in a sense, pyramidal shape: when the half pulls apart it should pull in a way so that the surface doesn’t slide along an edge. It also means the part has to push out: holes must be parallel to the direction the mold halves pull apart.

There are other design limits on plastic injected molding. For example, element sizes cannot be too small or too thin; otherwise, the mold may not fully fill or the part may pull apart as the mold halves are separated.

There are limits on other manufacturing processes as well. 3D printing cannot print elements suspended in space; they must be “self-supporting” as the part is “sliced”. CNC milling can only remove so much material at a single pass. Sand casting results in components that must be milled or polished.

And each manufacturing process takes time, effort and equipment. So minimizing the number of manufacturing steps and components that must be assembled helps reduce costs and reduce material required to manufacture a thing.

This is quite a complex field and I cannot pretend to begin to understand it. I do have some experience with embedded design, however, and part of embedded design is determining ways to create the software necessary for your product which reduces the total component count on a circuit board: if you can use an embedded processor with built-in I/O ports and fit your application in the memory of that embedded processor, your (essentially) 1 chip design will be far cheaper to manufacture than a design which relies on a separate microprocessor, EPROM chip, RAM chip and discrete decoders and A/D encoders, each of which requires a separate chip.

And this brings me to something which irritates the crap out of me regarding user interface design and the current way we approach designing mobile user interfaces.

Have you seen a project where there seems to be a dozen custom views for every view controller or activity? Where every single button is independently coded, and then there is a lot of work trying to unify the color scheme because every control is a slightly different shade of blue?

This is because the UI designers who worked on that project are thinking like artists rather than like designers. They are thinking in terms of how to make things look nice, rather than designing a unified design. They are thinking about adding new pages without considering the previous pages, and considering how to lay out elements without considering previous elements–other than in the artistic sense.

They are not designing for manufacturability.

There is far more to consider when designing the user interface of an application beyond simply making the application look pretty.

You must consider how people interact with machines, including the limitations of how we interact with computers, including the limits on our short term memory or our limitations on recognizing patterns.

You must consider the problem set that the application must resolve. If you’re building an accounting application, you must understand how accounting works–and that requires a much deeper level of understanding than a casual user may have balancing their checkbook. (Meaning if you’re building an accounting application, you may wish to talk to a CPA.)

You must consider how the application will be put together. As a UI designer you don’t need to know how to write code, but you do need to understand how objects get reused: if you intend to have a button which means “submit”, using the exact same button (same color, same frame, same label) means the developer can use the exact same code to create the submit button even though it shows up in several places. If you have a feature which requires the user to enter their location and that feature is used in a handful of places, you may consider having a separate screen which allows the user to select their location–and reuse that screen everywhere a location is called for.

And that means rethinking how you design applications beyond just creating a collection of screens.

That means considering a unified design for layout, for colors, fonts, buttons, and all the other major components of your application. That means thinking less like a page designer and more like a branding designer: creating unified rules covering everything from color to font choices to spacing of key elements which can then be reused as new screens are required. And it means sticking to these rules once developed, and communicating those rules to your developers so they can build the components out of which the application is built.

It means thinking like the designers of the Google Material Design, except on a smaller and more limited scope: thinking how your application looks as an assembly of various elements, each of which were separately designed and assembled according to the rules you create.

It means not thinking about an application as just a collection of screens, but as a collection of designed components.

Designed for manufacturability.

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