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. The misconception that smaller, or lighter, devices cost less comes from two different sources:
The psychological issue is that people tend to subconsciously attribute greater value to objects that are bigger and heavier [1]. While people may not be surprised to learn that high-end miniaturization technology comes at a steep price, they still often dismiss smaller objects as being of little value. This is fairly evident with 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 computers, and then tossing their smartphone around. Chances are their phones cost as much as their laptops, maybe more, and yet one is considered a valuable piece of equipment, and the other is practically disposable.
This subconscious assessment of value based on weight and size can negatively affect a miniature product’s commercial viability. If customers think the item looks or feels cheap then they won’t want to pay a premium for it. This is generally taken into consideration as part of the usability/human factors design process, but otherwise has little impact on the product development process.
The bigger problem that I see with this misconception is when it is not subconscious but rooted in either a misunderstanding or in misapplied knowledge. I see this most often in startups because they lack experience, and from manufacturing engineers who have great experience but not necessarily directly applicable experience.
Startups often must sell their concepts to investors prior to hiring an engineering team or doing a deep dive into the scope of work. It is shockingly common for startups to come through our door with preconceptions about the cost of their device that are based on misconceptions of product costs, in general. Sometimes they refer to the MSRP of a device, such as an Amazon Kindle, as a baseline without realizing that the device they are referencing is a loss-leader [2] sold at or below cost. Often, they underestimate the product cost simply because the product is physically small. I can’t count the number of times I’ve heard the statement, “this thing is just a few cents of plastic and a circuit board,” applied to a product concept with a complexity comparable to a smartphone.
Startups also tend to dramatically underestimate the cost of developing miniature devices. Apple does not release many statistics about their engineering teams, but 60 minutes ran a piece on the iPhone 7 camera back in 2015 explaining that just the iPhone 7’s camera design required 800 engineers and specialists [3].
The most challenging misconceptions relating size to cost come from people who have some background in designing and manufacturing devices, but not specifically in miniaturization. At the size scale of benchtop or freestanding equipment, a reduction in size often results in a reduction in cost. This is because materials, footprint, and handling are among the cost drivers of those devices. Costs are reduced by using less material, less machine/floor space, and eliminating any specialty equipment required for handling large or heavy parts.
For miniature devices, the equation is reversed. When a certain density of components and functionality is reached, any further reduction in size requires the use of more expensive materials, more expensive manufacturing processes, and increased handling costs. This is true for mechanical designs as well as electronics designs. For example, the iPhone 5C reduced cost by replacing the iPhone 5’s expensive aluminum enclosure with a lower cost polycarbonate enclosure. The aluminum iPhone 5C polycarbonate enclosure is nearly twice as thick as the iPhone 5’s aluminum enclosure, but the 5C enclosure reduced the enclosure cost by an estimated 40%. [4] [5]
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 some form of blind and buried vias, usually laser-drilled microvias. Additionally, the very fine traces in these miniature devices also increase the risk of etch failures, either short circuit or open circuit, requiring tighter process controls and more thorough inspection.
As with most misconceptions, the misconception that smaller size results in lower cost is not wrong in every case. The problem is that it does not apply to many miniature device designs where reducing size can dramatically increase costs. It is 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 to have good systems engineers to manage the tradeoffs.
[1] This assertion is an extrapolation from studies demonstrating that people ascribe 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 higher monetary value to larger or heavier objects directly. https://www.ncbi.nlm.nih.gov/pubmed/19686292
[2] https://www.ncbi.nlm.nih.gov/pubmed/10598479
[3] https://www.cbsnews.com/video/the-anatomy-of-an-iphone-camera/
[4] https://technology.ihs.com/451424/apple-continues-familiar-design-and-pricing-strategy-with-iphone-5c-ihs-teardown-reveals
[5] https://technology.ihs.com/410378/iphone-5-carries-199-bom-virtual-teardown-reveals