U.K. Shop Is Turned On To Lights-Out Machining
Fisadco Engineering, a Hull, United Kingdom precision machining firm, had some reservations about unmanned machining, but it has become a staunch advocate since it installed a Tornado 220M lights-out turning package from Colchester CNC (Kalamazoo, Michigan) in 2004.
Fisadco Engineering, a Hull, United Kingdom precision machining firm, had some reservations about unmanned machining, but it has become a staunch advocate since it installed a Tornado 220M lights-out turning package from Colchester CNC (Kalamazoo, Michigan) in 2004. In addition to boosting output, reducing machining costs and lead times and optimizing setup routines, the investment has helped Fiscado's Managing Director Daren Smith win new business, lower tooling costs, reduce demands on inspection and cut reject and scrap rates.
"Our initial reservations about lights-out machining were mainly based on accuracy, safety and the efficiency of monitoring key dimensions," Mr. Smith explains. "However, the machine builder assured us that the lights-out package was the way to go with its programmable bar feed, on-board scheduling software, broken tool detection, backup tooling and Renishaw probing. The builder said if there were any problems, the machine would simply switch itself off."
Cuts Costs By Up To 40 Percent
The machine was installed and, after a few trial jobs, the three-axis mill/turn center had demonstrated its capability for consistent cycles through the night by producing high quality components, including parts that required milling using the lathe's driven tools. With the lights-out package, the shop found itself able to quote work that was previously considered unprofitable. Mr. Smith found he could beat off competition by reducing hourly rates and lead times on certain projects, figuring that costs could be reduced by up to 40 percent compared to running a manned machine during the day.
As a result, his company has been able to offer competitive proposals to win new business and to reclaim an increasing number of jobs that had been lost to overseas producers. Mr Smith adds, "While we still can't compete directly to cost with such low wage rate economies, our service and quality is far superior and consistent, and we can now realistically offer half the lead time with the new machine."
The decision to buy the lights-out package was not that difficult since the company already owned two Tornado CNC lathes, including a standard 220M three-axis model that handled all of the shop's turning work. It was just the skepticism of whether unmanned machining was a viable option. To help ensure success, the company established selection criteria to ensure the suitability of jobs to be run unmanned at night. In essence, lights-out components must be easy to probe for key dimensions; have simple profiles that do not require too many tools; involve a material or process that doesn't generate chip nests; and involve batch sizes of 100 or more.
Fisadco has even put together different jobs, which can be machined from the same bar size. Jobs can also use the machine's on-board scheduling software in the Fanuc control to stop the process, automatically initiate the next program, initiate the tools held in the 12-station turret, and start on the next batch. Typically, the Tornado is setup for unmanned working between 2 and 3 p.m. and again around 5:30 p.m. as the staff leaves, and the building is secured for the night. The machine not only runs unmanned at night but also during the day, enabling operators to focus on other tasks.
Monitoring Provides Extended Tool Life
The new machine's tool monitoring system has proven effective, enabling tooling to be optimized on this system and the shop's existing (not lights-out) lathes. The conventional three-axis lathe is only run during the day. Its tools are changed at preset intervals on specific jobs as a safety measure, regardless of their actual condition. However, the availability of tool monitoring on the new machine has enabled the company to precisely measure tool wear. "With the introduction of tool monitoring, we now have very accurate life data, and this has helped to fine-tune all of our tooling," Mr. Smith explains. "It has allowed us to extend tool life by an average of 25 percent."
An example of the shop's lights-out machining success is its production of train door spindles in batch sizes of 4,000. The machining cycle involves basic shaft turning of several diameters and a small amount of milling on one end of the 20-mm diameter by 60-mm long EN1A steel component. Compared with manned machining during the day, these parts are produced unmanned at night, thus cutting the lead time in half to 2.5 days instead of 1 week. Tool life has been increased by more than 20 percent because of more accurate data. Inspection time is greatly reduced since in-cycle probing of one part in three requires only a final inspection. As a result, the cost to produce the spindles has been halved.
Fisadco also produces acetyl spherical bearings for the automotive industry in batches of 2,000. The unmanned machining routines for the bearings have cut inspection times by 80 percent, reduced lead times by more than 40 percent and saved a further 20 percent on rejects and reworking.
With the shop's current selection criteria for unmanned working, the Tornado runs unmanned two nights each week, but this is changing fast as more suitable components are ordered by customers. This has persuaded Mr. Smith to take on more complex work for the night shift now that the operators have become familiar with the unmanned machining practices. Mr Smith concludes: "We are delighted with the performance of the new Tornado. It quickly proved that the concept of lights-out machining is a highly practical and profitable proposition."
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