How to ensure long-duration manufacturing of central components?

Although this is not stricty an electronic design question, it is important to most design engineers. Component sourcing is one of our biggest headaches, and most companies are smart in letting a separate person deal with it instead of causing severe depression and anxiety in the engineers.

There are three ways to combat this, aimed at three different tiers of products:

1. Not-terribly-hard-to-make products should just be adaptable. Say you are making a custom board with expected 100-1000 units production per year. Just design in whatever you want, and when you get a product change notification from the manufacturer that one of the parts is going out of production: use another component and just eat the engineering hours. Terrible as this may sound, this is often economically the best idea in this respect. Even large production runs work well with this model; just produce a new variant of your product that is functionally the same. This is being done in the consumer and professional space all the time.
2. Small-run, specialist products that took a lot of man hours to make. For instance specialist scientific tools. The best course of action is to do a good estimate of your required components during the service life of the product and buy twice as many components as you will ever need. Cost is rarely a factor, so even though this will cost you quite some money in advance, as well as space to safely store it all, this will be alright. Don't underestimate storing cost: they need to have very specific, tightly controlled atmospheric conditions, especially to ensure solderability.
3. Medium to large run long term support products. Here, you will want to get a direct line to the manufacturer of your chosen product and ask them to either (a) produce a special version for you with a specified service time or (b) when the PCN goes out, ask them to make those chips specially for you. All MCU companies do this last bit. If you want at least 10.000 chips, even ones that have gone out of production for 20 years, they will happily make them for you - at a nominal fee. However, this is only possible if you need at least in the order of 10 000 units, often even at least 100 000.

Very few companies guarantee any kind of long term support on their components. Even so-called 'design for long term use' automotive parts from Microchip are only guaranteed production parts for 10 years, which is nothing compared to the lifetime of some specialist gear. You will always need to check in directly with manufacturers to ensure availability in the long term.

The bottom line is this: If you want to guarantee that you can make your product far into the future then you (or your company) need to do things to make sure that happens. While your various suppliers might assist, in the end it is all up to you. It shouldn't be that way, but it is. Here are some steps you can take to help:

1. Maintain a good relationship with your distributors and manufacturers reps. These are the people who can best watch your back, and notify you about potential supply issues.
2. Check, frequently, for End-Of-Life (EOL) notices from all of your suppliers. While your rep or distributor should tell you about these things, you cannot rely on them. Check on a monthly basis on the various manufacturers web sites.
3. Expect to keep extra stock on hand of the critical parts. Not only does this mean having capital tied up in stock, but having the infrastructure to store these parts (humidity controlled chambers, etc.)
4. Expect to make a large last-time-buy of critical parts. This means having the money or credit available to do that and, again, having a place to store the parts when you do get it. Depending on the part cost, and your volume, this might require purchasing anywhere from US$1K to US$1million worth of parts in a single purchase!
5. Expect to redesign the product sometime in the future. This means not only budgeting for this, but also requires that you plan ahead and archive key documents, files, and equipment. I would go so far as to setup a development PC with all of the tools and then STORE THE ENTIRE PC. Nothing is worse than having to redesign a product only to find out that you need a copy of Windows that is unavailable and won't run on a modern PC, or you need an I/O port that is obsolete and unavailable. Make backups of the files, and revisit the backups once a year to prevent bit-rot (making sure that the thumb drives, CD's, and hard drives have not deteriorated or are too old to use in a modern PC).
6. Do the obvious things like choosing components that have a high chance of being around in the future, and made from a mfg that will be around. But this does not override any of the other things on this list. Just because a mfg says that a product will be manufactured for 10 years doesn't mean that they won't go out of business tomorrow.
7. Be paranoid and proactive. Ultimately you are the only person/entity that cares enough to guarantee things into the future.

There are no guarantees.

It does help to look at the past history of a company to see how it deals with obsoleting old products. Some companies go to great lengths to make sure the legacy products are taken care of. Others dump them as soon as newer versions are available.

Microchip is a good example of the former. You can still buy a PIC 16C54, although you'll pay a few dollars more for one than for newer parts that do more. Companies like Maxim are at the other end. Different companies do have different philosophies and cultures.

It also helps to look at the market a component is being sold into. If the primary customers are cell phone companies, for example, then the component may dissappear quickly. New models of cell phones come out so fast that cell phone companies don't much care about component availability 5 years after first release.

Avionics and medical are examples of the other end. In both cases, the cost to getting a product certified and accepted is long and expensive, and product lifetimes are long and the products are expected to continue operating in the field for a long time (10s of years). A company that makes parts for these markets will likely go to extra lengths to make sure old products are available in the future, even if the price will be uncompetitive at the time. It's a lot better to keep buying a PIC 16C54 for $5 for use in a $10k medical device than to redesign it to use a newer PIC.