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better production Shops Using Technology 138 MMS June 2014 mmsonline.com compensated for wear made them very inconsis- tent. Given that the plated tools have just one layer of cutting tool, they do not permit dressing after plating to guarantee that the first part is good all the time. As a result, Micron says that tool change was a nightmare. According to the com- pany, sometimes it took weeks of trial and process adjustment to find a tool that could hold the size and sur face finish specifications. This caused severe, frequent disrup- tions in the production process and necessi- tated a bank of parts to cover the customer pull during nonproductive phases. Approximately 25 percent of the tools could never meet the finish requirements and had to be scrapped. As a re s u l t, a l a rg e to o l i nve n to r y wa s m a i n - tained all the time. Another problem with the diamond sizing pro- c e s s wa s th at i t wa s consuming most of the a llowa bl e pr int to l e r- ance, which significantly i n c r e a s e d t h e f i n a l inspection costs. Also, the final inspec- tion process could not identif y which tools in the various stations were worn. The operator had to m e a s u re th e b o re s i ze i n e v e r y s t a t i o n individually, and then replace the worn tool. These frequent stop- page s, in addition to causing downtime, also had a detrimental effect on tool life. For example, if the tool in the roughing station (the first station) were to wear at a faster rate, the resultant bore the honing spindles in the diamond sizing machine were driven by a single motor and mounted on a slide. The rotary index table moved the part from station to station, and the par t was inspected manually at the end of the cycle. These factors caused Micron to experience numerous problems while producing the fuel injector housing with this process. For instance, the way that the system's tools 0614_MMS_better.indd 138 5/14/2014 8:50:08 AM