I would comment on Roy Sakelson’s editorial [The Way We See It: “Double Talk,” page 9 August 2004] regarding the problems concerning inventory as it relates to the manufacture of PWBs.

Most PWB manufacturers offer a “fast turn round service” when batches of boards are pushed through the processes in order to meet a special delivery requirement. The manufacturer usually requires a premium price for such orders and will thus increase his “overmake” quantity to ensure that the correct number of parts is delivered on time. After all, the batch is being made at a premium price.

The problem can be that a number of other part numbers are delayed as a result because it takes a very strong nerve in this day and age to leave capacity for such eventualities.

However, if JIT is replaced with a policy of MJIT (manufacture JIT), those problems would reduce, thus facilitating less work in progress, fewer reworks and little scrap. This in turn would reduce the cost of inventory, and increase value added.

I would like to put forward this scenario and suggest that all batches of work in progress are processed in the same timescale as fast turnaround.

“The man’s mad” I can hear the cry! “He must have landed on his head whilst playing for the Bolton Over 60’s Nudist Leap Frog Team!”

“He’s retired you know,” I can lip read some comments, “He has no idea of present problems of PWB manufacture.” Well, they may be right. I have never been certified as sane and I have indeed retired from the front line, but I have been beating this drum for the past thirty years. Please spend a little of your time considering the following ideas, for which I claim no originality.

PWB manufacture is a long sequential process and in order to make a batch of work in your specific minimum timescale, you need to know:

That all your processes are reliable and can achieve 100% first time yield when being operated at their optimum values.

That your supplier is competent and fully acknowledges your yield requirement (If only…).

That your processes are maintained at optimum values.

That your operators know your requirements and are able to recognise processes that fall below this standard. (For example, a chemical cleaner is knackered if it shows water breaks).

In almost forty years as a supplier, I would say that the reasons for less than satisfactory yields are: Poor quality control, bad housekeeping, poor training, processes that are at the limit of their capability with impractical operating windows, and finally, a lack of technical expertise from the supplier, who recommend products not suitable for purpose.

Once reliable (belt and braces) products are installed, it should be possible to determine the time required for complete processing of each type of PWB. Then add a bit extra time to compensate for the totally unexpected.

It now becomes a matter of faith in that work should be pulled through the various processes in your decided timescale. Orders should not be started until a few days before despatch is required. Queues are an anathema to this principle and serve only to disrupt normal flow. In such (hopefully rare) cases all resources should be dedicated to resuming normal operation.

This system works well in many complex manufacturing processes, so don’t tell me PWB manufacturing is unique. Your supply chain management is critical, but a good partner is likely to be enthusiastic about the concept.

Finally, I suppose that your customer needs to be educated in your system and be aware of your capabilities. They too will benefit from short lead times and increased quality.

Think about all the benefits, and if you think it makes sense, start today in planning it’s implementation. Maybe in a couple of year’s time all your orders will be capable of being processed in five days (and with only a small premium for your customer to pay). Ask the Chinese to do the same. If you think its rubbish, my name is Fred Boggins.