Change is the enemy. Keep it the same day after day. Refine. This is what manufacturing likes. This is not what manufacturing gets. Changes happen on different levels. Changes in order quantities such that we have to adjust the work-orders and schedules. Variations in the bill of materials due to some engineering change, perhaps made to improve the product quality, reliability or perhaps just to reduce the cost. It causes disruption, but there are procedures to cope with that. The risk of making a mistake and the cost of implementing the change is as good as the procedure and the adherence to that procedure. These kinds of changes are normal and we can cope with them.
There are other kinds of changes however. A shortage of materials in the market, the purchasing division sources some alternatives. Different sizes, shapes, even a different supply form in some cases. These changes are more difficult and more costly to implement. For those of us with good material management systems, we can cope with this, we have a procedure, we reduce the risk and the cost. Cutting the alternative parts in and out, changing the machine programs, recording the change in the traceability files, changing the AOI programs and knowing which boards and which references have changed.
Then there are complex changes such as those related to “light classes”. This is not a simple alternative part scenario, this is a much more complex parts substitution problem – on the fly! Why? Well, go to the airport or anywhere that has those nice LED display panels. Look at any array of LED lights, now also popular as brake lights on cars. These LED panels are made up of tens, hundreds or even thousands of individual LEDs. Look more closely at the panel at the airport with its scrolling message. You start to see that a few of the LEDs are brighter than others. Some may be dimmer. Multi-coloured displays have the message changing tint as it flows across the display. Lack of uniformity an engineer may tell us. Uniformity is an important part of the quality of the display. Uniformity however is not a strong attribute in LED manufacture however. You really only know when you light it up with a known current how bright it is going to be. Of course, LED manufacturers are not going to let a thing like that prevent them from selling a quality product – they simply sort them into “classes”, each class has a range of brightness characteristic deemed acceptable at the desired quality level. All classes are as good as each other, but to get one class to shine at the same brightness as the other, different components or values in the support circuitry are needed. Back to manufacturing then, which class are we using? Design and engineering will have done their part, to set up sets of conditional substitutions. To put it simply, whenever one class is used, populate the parts with these values, but when another class, then use other parts with other values. This can happen at any time though, whenever the light class of the available parts changes. This is now true dynamic manufacturing, where risk and cost of change become a part of the process itself rather than a recovery procedure.
How many MES systems can handle this? It is just one of a number of advanced manufacturing requirements that are faced in SMT manufacturing that require special and individual attention. If it cannot be supported, we fall back on to a manual system with all the associated risk and cost. Having the support for these specialist requirements to ensure that risk and cost are avoided is a key differentiator in the choice of manufacturing systems. The Valor MSS suite is probably the one system available that has at its core the support for this kind of specialisation, out of the box and ready to go. It is the value point differentiation. This is all getting very interesting…..