Quote of the Day
As a child, you want something. As a young adult, you beg for relief from something. When you become old, you pray to give thanks for something.
— Kevin Kling, my characterization of his three stages of prayer. His observation very much reminds me of the Benedictine philosophy I heard in my youth, which taught that if you want to be happy think of something to be grateful for.
Figure 1: Engineering
Balances Time, Cost,
and Technology.
I spend a fair amount of time estimating the cost of electronic components with different purchase quantities. In earlier posts, I showed how component cost quotes often reduce by ~7 % per doubling of quantity purchased. In this post, I will present quotes from two different vendors for the same part (normalized to preserve confidentiality). The component quotes from each vendor reduced by 3.6% per doubling of quantity purchased, which differs significantly from my 7% rule. While each vendor had different costs, their rates of variation with purchase quantity were identical. As I thought about these quotes, their deviation from what I usually see made sense.
Normally, I am asking a vendor to deliver parts for which they have already built thousands or even millions of units. In this case, I am asking a vendor to deliver a part that they have never built before. Because of the risk associated with building a component they have never seen, the vendors are conservative and their cost quotes show only a 3.6% per doubling of component purchased. Note that the rules I am working with here are for purchases within a single year. A related rule (Wright's law) holds for year-over-year pricing (blog post).
Figure 2 shows the normalized quotes and my 3.6% cost reduction per doubling curve. I am documenting this information here in the hope it may be useful for those of you who must estimate cost reductions based on purchase quantities.
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| Figure 2(a): Quote from Vendor 1. | Figure 2(b): Quote from Vendor 2. |
Addendum
I will add quote charts here as I get them. Figure 3 shows a more typical example of how the cost quotes look. The device in Figure 3 includes significant amounts of passive optics and active electronics. I consider this component a mainstream device – no development risk.
Figure 3: More Typical Quotation Plot Showing 7.8% Cost Reduction Per Doubling of Volume.
Figure 4 shows the quote for a new passive optical component with rather aggressive specifications. Observe that the vendor did not price as aggressively for a new design.
Figure 4: Totally Passive Optical Device with 3.8% Cost Reduction Per Doubling of Volume.