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Latest processor ups lathe capacity
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Latest processor control on a sliding head automatic is giving a 20 per cent faster cycle time on an equivalent job when compared with a previous generation machine, reports a user. Five years is no age in the production life of a Citizen B12 CNC sliding head automatic lathe Indeed, many companies would suggest they were barely run in and once paid for, either enabled margins to be increased or hourly rates reduced Not so at Unicut Precision. Maintains joint managing director Charles Kenny: "We are continuously pushed for shorter delivery times so we traded in our two oldest machines which have served their purpose having run problem free for over 120 hours/week for two of the latest Citizen C16-VII machines. If we are to continue to compete successfully and in the international market against other subcontract suppliers, we need the latest and most appropriate production technology. That is how we grew 18 per cent in 2002 and another 20 per cent this year. Having rows of ageing machine tools, although fully written down, will become a liability to what we need to achieve." The two Citizen B12s were traded back to NC Engineering of Watford,UK, in part exchange for two of the latest Citizen C16-VII CNC sliding head machines to obtain greater flexibility from power tooling, extra end working capability and a larger production capacity for 16mm bar size. Comments joint managing director Jason Nicholson: "When we checked out other 16mm capacity machines in the market against the Citizen, the new processor control was impressive giving us a 20 per cent faster cycle time on an equivalent job than the previous generation machine which is equivalent to five days production every four." Now installed and running, the Welwyn Garden City, UK, company is well able to compare cycle times on difficult components having been transferred from the B12 to the C16. But says Nicholson: "We are looking much further then pure cycle time savings." As an example, he quotes a stainless steel component made of 320 stainless steel. "On the B12 we had to program a cycle stop after 100 parts to deswarf the machine due to the problems of swarf balling up in the machining area. While that could take five minutes to clear and check out the tooling, we often had more lost machining time waiting for the setter to get to the machine. In all, efficiency on this particular job was around 65 per cent and worse still, it could never be left to run unmanned." The C16 is a totally different machine maintains Kenny: "The frame is more rigid, the spindle bigger and higher powered and there is a far better flow of coolant. As a bonus, the machining area makes setting easier and we have better swarf control." He then focuses on other savings: "Immediately, turning tool life went from 300 to 1,000 parts between insert changes and we used to get 1,100 parts per shift on the B12 now we can run off 1,692." To date some 40 different parts in mild steel, 316, 320 and 303 stainless steel, brass and aluminium have been run on the two C16s and Unicut has found on more simple parts when using three or four tools, the cycle is about five per cent quicker. This is because of the very short tool strokes required, which is where the B-series tool arrangement made a distinct advantage. However, on more complex work there is a major advantage of the new machine when five or six tools are required. Here, the cycle times tend to be between 10 and 20 per cent quicker which is a beneficial saving. "The more tools the greater the saving!" maintains Nicholson. Originally Unicut ordered the entry level C16-VIE version with six turning tools, three driven tools and a high precision four-station toolpost able to carry eight tools. These could be applied simultaneously to machine at the 10,000 rev/min main and secondary spindles. However, Unicut decided to upgrade to the VII machine. This has a 12 position toolpost with six tools facing each spindle and four driven tools. The two-axis yoke style tool slide is also able to mount four 8,000 rev/min rotary tools and the perpendicular toolpost holds six turning tools. According to Nicholson the extra flexibility of the VII for setting, enabled more complex work to be produced and cycle times to be further reduced because up to three tools can be brought in to cut simultaneously. Unicut also used the installation of the two new machines to set up its new cellular approach to production machining. Under the revised operational methods, all volume orientated jobs are assigned into one area, complex and high value work needing high levels of setter input are in another and the normal batch run components make the third grouping. Having identical machines always pays dividends giving maximum flexibility, Unicut maintains, and even though the control system had been completely upgraded, the C16s are very similar to Unicut?s seven other Citizen installations. "This made training simple, all tooling was interchangeable and both machines were in full production within a couple of hours of being installed and commissioned," concludes Kenny. http://www.manufacturingtalk.com/news/nce/nce173.html |
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