SMT007 Magazine

SMT007-Aug2020

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56 SMT007 MAGAZINE I AUGUST 2020 a carrier, such as on a reel, in a box or car- ton, etc. The difficulty is that during manufac- turing, all of these aspects of knowledge and control are fluid, changing several times every second as materials are allocated, moved, and used. Keeping track manually or by ERP has, in the past, proven to be nearly impossible and certainly impractical. The Stock Check Symptoms of the lack of trust in material inventory are easily and commonly found. The periodic stock check entails going through the whole factory and warehouses, counting up the quantities of physical materials. This pro- cess can take a couple of days, even with a massive focus of manpower. The factory will be stopped for most of this time to enable an un-fluid snapshot to be taken, which costs the operation around 1% in annual lost produc- tivity each time the stock check is performed. The result is usually much more painful, as significant discrepancies between the physical stock, and what ERP has as inventory levels, are revealed and have to be financially writ- ten off. In medium-sized electronics manufac- turing sites, around $1 million in write-offs of "lost" materials per year, is not unheard of. In terms of cost savings, in this aspect of mate- rial management alone there is a great deal of potential justification for a solution that can eliminate these discrepancies. Where Did It All Go Wrong? Immediate culprits are easy to identify. In the electronics sector, and in common with other areas of automation, SMT machines throw away materials during their operation that they cannot pick up and recognize in exactly the way they need. The setup of feeders and vari- ations in material dimensions can have quite an effect on the rate of this form of spoilage. A feeder set to the incorrect pitch can create 50% spoilage without anyone noticing until later, when an unexpected internal material short- age happens because materials that ERP iden- tifies as available no longer exist. Materials are also lost due to repeated han- dling, especially part-used materials in SMT that need to be put on and taken off from feeders and other carriers. All materials, however, can be lost or damaged whenever they need to be "touched," including becoming contaminated. In addition, materials become too old to use or obsolete after the relayed product's end of life. The symptom of the need to perform a stock check is the occurrence of unexpected mate- rial shortages. Having to stop or delay produc- tion is bad, but in many cases, it's not even the worst issue. The immediate response in such cases is the mandate to maintain higher levels of buffer stock, which leads to holding excessive inventory on the balance sheet. ERP will not order materials unless it can see the requirement, so the required buffer levels in the system have to be increased. It is not the fault of ERP that it is mind-numbingly difficult to manually count and update the attrition of every lost part; it just doesn't get done. ERP also has additional challenges when the consumption of materials is not registered until the product is completed. Materials may be in the factory, many of which are already on a partially assembled product. If the com- pletion of that product is delayed, perhaps due, ironically, to lack of a material, the prob- lem compounds. The knee-jerk reaction, going back decades, is to bloat the stock levels, even though it is expensive, risky, and not good for the bottom line of the business. In the vast majority of manufacturing operations today, we find bloated inventories, with (hopefully) enough materials to carry the operation from one stock check to the next. And then COVID- 19 comes along. What Do We Do Now? As humans facing COVID-19, we bought toi- let paper, bread, and wine. I'm not sure what the connection is between these items, but what food items should we stock up on? For too long, people in manufacturing have been concerned with the supply of critical materi- als, forgetting that the absence of any part, no matter how insignificant, will mean the prod- uct cannot be completed. As humans, we can go without chickpeas or avocados for a cou- ple of weeks, but in manufacturing, the full set

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