Designing for the Indirect User
When designing a new product, a great deal of effort and imagination goes to the moment when our end user takes our product in her hands and starts using it.
However, design and ergonomics should not be a consideration reserved exclusively for the end user. There are plenty of indirect users and stakeholders involved, and their impact can be critical. They are everywhere: they are in charge of manufacturing, assembling, packing, inspecting, shipping, storing, or providing customer support for our products.
Even if the signed off version of our product seems fine, a lack of planning towards the indirect users’ experience could mean delays or additional costs just to get us out of trouble. Here is an example of something that happened to me:
The plastic pin and the carbon footprint
A while ago we designed a plastic-injected pencil holder in the shape of an oil barrel, and one of the client’s requirements was a second color in the middle. A few iterations later we decided that the best approach would be to assembly two C-shaped sleeves with a pin and a boss, ultrasonic welding, and a small indentation in one of the parts to prevent the whole assembly from rotating. All fine… in theory.
When the molds were ready and we started testing them, we noticed the plastic flow left some unappealing patterns. In technical terms, a sinking in a plastic part means an obstruction in the mold cavity that splits the plastic flow and creates the “racetracking” effect. All this was not a big deal, but it distracted us from the real problem: the pin/boss assembly was a bit too tight, and it demanded some extra strength from the workers to achieve the “snap” fit. Assembling 10 components would not be a problem, but with a daily production of over 3,000 items, it quickly became an issue, and some workers had to start using gloves to protect their hands. The situation did not affect other aspects of production, but it delayed the final shipping date for a week.
A minor event — or so we thought- escalated to an undesirable situation: delivery delays and overtime for factory workers. Moreover, we had to send partial deliveries every day for a week, increasing freight cost and carbon footprint. And all of this because of a tiny plastic pin 0.1 mm thicker than it should have been.
Planning a product for the end user is not enough. Ergonomics for manufacturing is just as important and it can have a tremendous impact on your total investment. To make matters more challenging, this kind of issue can be very difficult to detect from prototypes or 3D prints.
A useful exercise is to simulate what we would do in terms of raw material, transportation, worker hours and warehousing if production requirements spiked 400%. Whenever possible, I try to visit the manufacturing facility and go through every step in detail, even if they are working on a different product. Does it seem like a hassle? Try daily deliveries for a week.
