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feature night could simply reveal another problem that would halt the same process on a later night. Any process on any CNC machine might be susceptible to eight to 10 infrequent production-stopping problems, all of which had to be discovered and resolved before the process could be trusted to run with no employee present. Again, these were not big problems. A bar feeder loading material into a lathe might fail to trip a switch properly only on rare occasions. By day, the problem went unseen, because an operator noticing that the lathe was not cycling could clear the error and resume production within a minute or two. Something similar might be true of a chip wedging into a strange spot to affect the subspindle chuck, or a cutting tool breaking instead of gradually wearing. While such problems are uncommon, knowledgeable operators spot them and address them easily enough that shops might underestimate how frequently they occur. Yet even infrequent problems add up. Consider this: If eight potential glitches each stop a particular process only 1 time in 20, the result is a process that will successfully run unattended only two-thirds of the time. So the shop fixed problems one after another Workhandling keeps Work in The UniTed sTaTes For Hogge Precision Parts, workhandling automation proved key to saving a job that came close to being sent to China. The automation in question was not for loading the work, but for safely removing it from the machine. The part was heavy, valuable and made from a soft metal, Mr. Hogge says. When a finished piece dropped from the turning center's exit chute into a bin, it would often damage another piece it landed on. As a result, a part could complete the machining cycle successfully and Like the bar feeder, the carousel accommodates a range of part sizes. The larger part seen here was run on this automated system immediately before the smaller part, with little change-over between the two different jobs. be ready to ship to the customer, only to be scrapped because of what happened when it left the machine. "We had an employee standing at the machine unloading it by hand, but we couldn't keep the job that way," Mr. Hogge says. As long as labor was significant to the process, the expense of that labor would make machining in China a lower-cost option. As it happened, Royal Products had faced a similar problem. The maker of machine tool accessories in Hauppauge, New York had been damaging lathe centers by allowing them to drop from the CNC lathes producing them. To solve the problem, the company invented a carousel system for gently removing and collecting finished pieces. The company markets this invention as the "Rota-Rack," and Hogge Precision Parts learned about the product from machine tool supplier Machinery Solutions. Mr. Hogge says this system enabled the shop to run the job without an operator. This, in turn, enabled him to lower the price of the job sufficiently to keep the work. In general, he says, the machine tool itself is not all that significant to achieving lights-out production. Presumably, a shop is already using a capable machine tool and knows how to use it effectively. Instead, the key often lies in finding and proving out the right systems for delivering the work both to and from the machine. mmsonline.com September 2013 MMS 93