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February 2015 • SMT Magazine 97 STOP THe SMT CONSPIraCy, ParT 2: abduCTION continues the essential pioneer's survival Guide What Happens in Production, Stays in Production The production manager openly admitted that his priority is to keep the production lines working at all times because that was the core of the value generation of the business. He and the warehouse manager agreed that oversupply is essentially insurance against material sup- ply issues causing production downtime. It was thought of as a trade-off; after all, neither the warehouse manager nor any of his guys wanted to work the night shifts. Chuckling, the produc- tion manager left us momentarily to order us some coffee. While the manager is momentarily absent, a young production engineer turned informant. He said that often the materials prepared in the warehouse kits are not enough. At night, with the machines on stop, machine operators have to go looking for materials and will take what- ever they can find, which includes taking mate- rials from the warehouse. The production manager returned. I asked what happens to the oversupplied materials. The production manager and the engineer ex- changed glances. We are told that the partly used materials should be returned to the ware- house, but with the time and effort needed for counting, this only happens for expensive key materials, and only then if there is a significant quantity. Production generally keeps materials on the shop floor to cope with cases where the warehouse undersupplies or there is a sudden spoilage issue. The undersupply happens if the warehouse manager thinks that there should be enough excess materials already issued in ear- lier kits that should be reused. He often gets it wrong, or at least he often cannot find it. The spoilage issue, while averaging out as a fraction of a percentage of materials overall, can suddenly peak if reels are loaded and un- loaded onto feeders several times, if the feeders have been set up incorrectly, or the material it- self becomes damaged. In those cases, with the warehouse working so far in advance of produc- tion, it is up to production to manage replace- ments. The ERP system cannot account for ma- terials on the shop floor, so, as the production manager explained, they take control. I suspect, however, that this is not always their highest priority. There are thousands of reels and trays of materials, stacked up on unlabelled shelves, all mixed, some on feeders, and some not. I am not surprised that materials would be difficult to find, such that in a line-down situation, it may be far easier to look in the warehouse. The volatile nature of material spoilage around the SMT machines seems to account for some of the material losses, but surely not all. Having such bloated inventory in the warehouse and a huge quantity of unmanaged materials on the shop floor would indeed make it very dif- ficult to identify when or where problems be- gan and things went out of control. It was time to talk with the engineering manager, who, for some reason, was not surprised to see us. View From the Outside We were told that when the supply chain operation was viewed from the engineering per- spective, the whole system seemed open to er- ror, but there is yet more to the story. We were also told that in many cases where, for whatever reason, materials cannot be found on the shop floor or in the warehouse, the engineering team is called on to approve an alternative part that could be substituted in place of the original ma- terial. Engineering are required to sign off on these because the substitute part needs to per- form correctly in all instances, and it needs the correct form factor to fit properly on the PCB. This happens mainly with common generic materials, like resistors and capacitors, where no one keeps a close eye. The lack of any material, no matter how valuable, will shut down production. The engi- neering qualification service was already part of the engineering role, as purchasing continuous- ly seeks to qualify alternate materials that may be less expensive and more readily available. Even after qualification, however, there can be a lot of problems with alternative materials; for example, if there is even a slightly different height, it can significantly influence the degree of spoilage, because the pickup of the part will fail more often, unless the library in the ma- chine is adjusted. We were told that material substitution re- ally should happen less often than it does, and that the quality manager is continuously criti-