20 July 2011
The most expensive component in the world
With great apologies to William Shakespeare, "a resistor, a resistor, my kingdom for a 47k, 1% resistor in an 0805 SMT package on a tape and reel dispensor."
That cry, or similar, has been echoed by many electronics designers as they find out that the lack of a simple component has held up the manufacture of a crucial board.
If you think about it, the logistics of manufacturing electronic devices is a hugely complex operation. The right versions of the right files need to be in the right places. The right components need to be in the right delivery format and available at the right time. With so many dependencies, it's a wonder anything ever comes off the production line on time, within budget and in working order. Ask a lot of engineering managers and they'll probably tell you it usually doesn't!
It's strange then that the challenges associated with taking a design from the computer and into the manufacturing plant get so little attention at design time. This is particularly true of parts procurement and the supply chain in general.
In typical design and production flows today, procurement is viewed as a post design process. A designer creates his or her circuit from a library of, hopefully, company approved parts. At the end of the design process the designer generates a bill of materials that is sent to the procurement department. The procurement department gets on the phone and the internet and finds sources for the all the parts in the design, negotiating with the manufacturer about the most suitable form - tape and reel, tube, tray - to supply them.
The problem with this is that when there is a problem, even a small one, it can derail the entire process.
If procurement discovers that a critical resistor you've specified is not available in the reel format the manufacturer needs in the time the manufacturer has allowed for your production run, then you have a problem.
If changing the board design to accommodate a different resistor package requires a complete redesign, and is therefore out of the question, you have a potential disaster.
Your decision to use that particular component in your design ends up costing the company big time. In short, that resistor ends up being the most expensive component on the board.
Of course we never view it like that. It's simply accepted as part of the business of developing electronics products. Sometimes you make a part choice that turns out to be a problem at the manufacturing stage. But that's procurement's problem, not the designer's. Or is it?
Globalisation of electronics manufacturing and, increasingly, design is having a major effect on supply chain management. In a nutshell, it's making it more difficult. Companies need to deal with a wider range of manufacturers that are geographically dispersed and encompass a plethora of manufacturing technologies and equipment. In this environment the consequences of poor component choices are magnified and can lead to a host of problems, delays and added costs downstream in the manufacturing flow. In a market where margins are being squeezed on all sides, this is a precarious situation.
If we are to make significant advances in bringing the next generation of electronics products to market, these issues should, and indeed need to be addressed at the design level. Designers need information about real world components - cost, availability, supplier info, potential equivalents - to make more intelligent decisions about the parts they specify at design time.
Basically, we need to bring supply chain intelligence into the design environment.
Rob Irwin, product manager, Altium Ltd