Last in a series of 3
This third part of my Misconceptions in Miniaturization series focuses on a misconception that is a little deeper, a little more subtle, and a little more pervasive than may be immediately obvious.
This is the misconception that smaller and lighter devices cost less than larger, heavier devices.
Psychologically speaking, people tend to subconsciously attribute greater value to objects that are bigger and heavier. This is evident in the attitude that people take with their smartphones. At a cafe in Boston during the daytime, you’ll see countless people gingerly handling their laptop computer while their smartphone is used as a drink coaster. Chances are that their phones cost as much as their laptops, maybe more, and yet one is considered a valuable piece of equipment and the other is disposable.
This subconscious assessment of value based on weight and size can negatively affect a miniature product’s commercial viability. If customers think the product looks cheap then they won’t want to pay a premium for it. This is an important consideration during the human factors design process, but otherwise has little impact on the product development process.
Unfortunately, the subconscious assessment of value based on weight and size is not limited to customers. It is also common for product developers to underestimate the costs to design or producing a product because of its small size. This is not a matter of inexperience, we see this happen in established product development teams as well as in startups. We are all susceptible to the psychological underpinnings of this misconception and we all need to work hard to avoid acting on this misconception. At Sunrise, we are all expected to critically assess our assumptions, but we also emphasize the role of the Systems Engineer as a second layer of defense against such misconceptions.
In general, phrases that start with, “it’s only a” or, “it’s just like” are red flags indicating that a preconception, and possibly a misconception, is about to be asserted. For example, it’s easy to underestimate how much it costs to add a small LCD to a device by thinking about it as “only a small screen, just like on a smartphone”. In reality, the cost to design a graphical display into a device correlates much more with the complexity of the UI workflow than with the display size. Then, at production, the cost of a display is driven much more by the LCD glass’s global production volumes than by the dimensions of the display. Consider, for example, that the component cost of a 6” smartphone display is often comparable to the component cost of a 60” TV display.
As with the other misconceptions about miniaturization, the underlying idea is not necessarily wrong. The misconception is a matter of the extent. Automobiles, for example, are macro-scale systems with large production volumes, so material costs are a significant fraction of the total production cost. Smaller cars generally contain less material and can, therefore, cost less than larger cars. However, below a certain size, making a car smaller and/or lighter requires replacing inexpensive steel and plastics with expensive composite materials. After this point of miniaturization is reached, reductions in size and weight tend to come at increasing costs, not decreasing.
This same principle applies to most products but is particularly prevalent in miniature devices such as wearables and smartphones. A very simple example of this is the iPhone 5C. One way in which the iPhone 5C reduced cost relative to the iPhone 5 was by replacing the iPhone 5’s expensive aluminum enclosure with a lower-cost polycarbonate enclosure. The iPhone 5C polycarbonate enclosure is nearly twice as thick as the iPhone 5 aluminum enclosure and weighs 20% more, but the iPhone 5C enclosure reduced the enclosure cost by an estimated 40%.
Miniature electronics also require advanced processes that can dramatically drive up costs. In electronics, we lump this problem under the umbrella term of High-Density Interconnect (HDI). Below a certain size, the component pin pitches get very fine (down to 0.3mm is common) requiring a very flat landing on the PCB. To meet this flatness requires a very fine weave substrate, or a non-glass reinforced substrate, both of which are considerably more expensive options than standard FR4. Also, below a certain size, the via density grows to the point that routing traces becomes physically impossible with standard through vias, requiring blind and buried microvias.
In general, it’s important for the design engineers to understand the different technologies available for miniaturizing their devices, to work closely with manufacturing engineers who can provide insight into the manufacturing challenges incurred by the design decisions, and have good systems engineers to manage the tradeoffs between size, cost, and performance.
Check out Misconceptions in Miniaturization Part 1 and Part 2
 This assertion is an extrapolation from studies demonstrating that people ascribe a higher monetary value to other things while holding a heavier object and from studies demonstrating that people assume that larger objects are heavier. As far as I know, no studies have explicitly demonstrated that people ascribe a higher monetary value to larger or heavier objects directly. Ref 1: https://www.ncbi.nlm.nih.gov/pubmed/19686292, Ref 2: https://www.ncbi.nlm.nih.gov/pubmed/10598479