Flexible and then Agile
Posted : October 4, 2004 at 7:05 am [IST]
Flexible manufacturing
Flexibility requirements have almost made the application of traditional inline transfer lines obsolete. Incorporation of NC-controlled feed units, multi-axis NC-units, swiveling drilling heads, sometimes head changers, flexible design of work transfer pallets provides a lot of flexibility in present generation of transfer line to be called rightly as flexible transfer. The idea of using even high speed machining center modules for flexible transfer line in the auto industry has become quite popular. Transfer system may be similar to traditional transfer lines, power and free conveyor, or conventional electromechanical one such as lift and carry system used in high production line. For lesser flexibility required by high production line, a trend is to strip machine tools of redundant features to trim prices by 30 to 50 %. Some simply reduce the number of control axes, cheaper controllers, and/or tool magazine’s capacity. Designers throughout the machine tool industry are working hard to make these high-tech machines cost competitive with conventional machines. Systems used for high production machining may be:
“Sequential machining on three-axis modular production-type machining centers with limited tool-changer capacity (say, 6 to 24), and dedicated hydraulic fixtures. Units can also be installed as wing bases on a dial index machine. In another setup, units can be positioned close together to form a transfer machine. Appropriate machines - heavier machining centers for milling operations; lighter and high speed ones for drilling, and reaming; a tapping center for fast tapping; a very precision unit for close tolerance boring; may constitute the machining line. The part moves ahead in sequence passing through all the machining stations.
” Asequential machining features identical CNC machining centers with a larger tool-changer capacity, each of which can do all machining operations for each part assigned to the cell, including milling, drilling, boring, counter-boring, and tapping. The system takes care of a machine-breakdown easily. The system may start with minimum number of machines, and grows with addition of machines as the production increases. The part moves as programmed to different work-stations depending on real time situation.
Agile manufacturing
A switchover from flexible manufacturing to agile manufacturing system is becoming a necessity. It provides the unlimited scope of changeover over the limited scope of change in flexible manufacturing. Instead of building something that anticipates a defined range of requirements based on ten or twelve contingencies in flexible manufacturing, the emphasis by an agile system is to build something that can be deconstructed and reconstructed as needed. Present trend prefers the use of cost-effective single spindle machining centers that are configurable as both transfer machine modules and standalone machines, capable of high force, high speed machining, and optimized for a range of materials from aluminum to cast iron.
All the machine tools for medium to high production are being designed with built-in agility as a necessary feature. For example, the totally self-contained electrical and power units are designed with a ’single plug’ system. Even a precision machine today is moved with a forklift truck, and then with a few connections and leveling, it gets ready for production. Agility does not compromise stability.
- Indra
Category: Machining |
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