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March, 2012 Really Managing PWB Supply By Stanley L. Bentley, P.E., Senior Technical Advisor, Divsys International LLC, and David Fissell, MBB Principal, Global Lean Consulting T
he harsh upheaval of the US PWB market has changed the dynamics by which suppliers
and users of PWBs interact. Fabricators have become brokers, blurring the lines between manufac- turer and re-seller. Further, aggres- sive roll-up companies have con- sumed dozens of former fabricators, eliminating their manufacturing capability while maintaining the name and sales activity but outsourc- ing the actual fabrication. Often this shift of production location has not been shared with the customers in a timely manner if indeed it has been shared at all. Consumers of PWBs often find
that boards they have purchased for many years have quietly shifted from an internal fabrication by a long- time supplier to an unknown out- sourcing supplier. This shift has left the companies who use PWBs with three fundamental questions: “Who has my Intellectual property?” and “Are my fabrication specifications adequate?” and, “If adequate, are they being followed?” The closely-knit customer/sup- plier relationships so common a
nerships so attractive has become a major hurdle for consumers of PWBs in dealing with the shift of supply location. The reason is a long-time supplier of any product acquires inti-
very sterile specification-driven pro- curement environment. However, this bond of “trusting
commerce” is extremely important to the success of the Book-of Business
ing only end product specs such as size and finish. The fabrication crite- ria is usually a reference to a class of the IPC A600 Acceptability standard.
IPC A 600H PCB Acceptability Users and fabricators have col-
laborated for decades to create these standards. The importance of their position can be exemplified by the loss of prefacing figures (such as IPC A 600) and these being shortened to simply “Class 2” or “Class 3”. Consequently, the prevailing
Lab technician eyeballs PCB standing in front of a non-contact co-ordnate measuring machine.
mate knowledge of the product to the point that drawings and specifica- tions become important only when a change is needed. Often, there is a slow shift of the product support to the supplier from the customer. The
All too often, yesterday’s trusted domestic PCB maker has started to send his work out to less trustworthy offshore operations.
decade ago worked very well because both parties viewed the arrangement with a common goal — to satisfy the end customer. Neither could be suc- cessful unless both were successful. The very thing that made these part-
customer may even reduce or elimi- nate internal technical resources and come to rely entirely on the supplier. This trusting, symbiotic rela-
tionship may seem simplistic when viewed through the lens of today’s
roll-up companies when the PWB purchaser discovers that a shift in production has occurred. If they also discover that they do not have ade- quate documentation about their PWBs, they are assured that the fab- rication data is secure and they can continue to receive the boards. The fact that the boards are re-tooled relying solely on the prior fabrica- tor’s files is seldom brought to light. The customers are assured they will receive the same product and it will be made to the specified criteria. Often, it is discovered that the
PWB consumer has few internal specifications relative to the manu- facturing process of the board, hav-
wisdom is that a fabrication shift is not a risk as long as the sales outlet provides a Certificate of Confor - mance (C of C) referencing an IPC standard. It is only fair to question prevailing wisdom by asking, “What is the validity or enforceability of a paper certificate from a supplier in another country?” Have we become so complacent
about accepting a paper C of C that we no longer understand its limita- tions? A new twist on an old concept is challenging this “paper” premise. The old concept is outsourcing
supply management. The new twist is applying this to Printed Circuit Board procurement. A mid-tier contract manufactur-
er (CM) was struggling with suspect- ed PWB problems. The CM did not have adequate internal verification capabilities to determine if their PWBs were actually fabricated to the desired specifications. They could perform a visual inspection and do dimensional checks, but they could not evaluate copper thickness, clean-
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