Multitasking Machine tools
Posted : September 20, 2004 at 6:54 am [IST]
Multitasking machines probably make up the most dynamic segment of the machine-tool industry. Multitasking technology is gaining in importance as more users realize the benefits of single-setup machining of complex parts and as builders make the machines easier to use and more capable.
Over the past few years, machines have evolved from essentially turning centers with some milling capability (or, conversely, machining centers with a rotary table that enabled some basic turning operations). Offerings now include unique machine configurations that combine processes ranging from turning and milling to grinding, honing, hobbing, inspection, assembly, welding, and others.
” Some prefer the term ‘integrated machining,’ which refers to operating on a part with one process at a time, sequentially, within the same machine.
” Some like Mazak talks about ultratasking–integration of a wider variety of processes into a single machine platform. Customers are increasingly accepting the multitasking concept, and they are also looking to move beyond milling, drilling, and tapping and add hobbing, polishing, and grinding to the workpiece while it is in the machine. Mazak sees an increasing movement into such ultratasking.”
” Some again want the term “multitasking” to be replaced with “multi-application” to describe the capabilities of the current crop of machines
In the not-too-distant past, we could say that a grinder with both OD and ID grinding capabilities was multitasking. Today, these types of grinders are almost common. The same may be true in the chipmaking world when it comes to turning centers with milling capabilities.
Use of multitasking equipment can support lean manufacturing initiatives. By setting up a machine once for several operations, we see the reductions that define lean: less material handling as the workpiece remains in one machine for multiple operations, less setup as the machine is placed in one flexible fixture.
Recently demonstrated the Schaudt Stratos can hard turn, mill, and grind a part in one clamping. The machine features an inverted vertical spindle that picks up a part from a built-in conveyor system. The part is then hard turned and machined in one chamber using an eight-station indexing turret with live tooling. The part is then transferred to a second chamber for ID and OD grinding.
Whatever you call it, the idea is to incorporate as many functions as possible in fewer setups to reduce tooling and fixture costs. Rarely does a company invest in multitasking equipment to produce parts in a traditional fashion. Instead, through solid modeling and more powerful toolpath-verification software, parts and components can be produced on multitasking equipment in fewer pieces.
As reported, Mazak, Japan is striving to create a “virtual machining” environment that accelerates both part and process development. Mazak’s latest two spindle Integrex 400-IIIST- the third generation in the company’s multitasking line- features 3300-rpm maximum turning spindle speed and 12,000-rpm maximum milling spindle speed, with 12″ (305-mm) chucks on both spindles. The upper turret has an automatic toolchanger and 20-tool magazine, while the lower turret is a nine-position drum. Linear guides on the X, Y, and Z axes allow rapid-traverse speeds of 1496, 1024, and 1496 ipm (38, 26, and 38 m/min), respectively. A roller gear cam mechanism on the B axis is said to achieve positioning in 0.0001º increments.
See another machine for multi-tasking. Mori’s SuperMiller 400 features a tilt/rotary table that provides five-axis machining center capability as well as turning to 1500 rpm on the A axis. The tilting B axis moves vertically over a range of -20 to +110º using a roller gear drive. Other features include a 12,000-rpm, BT40 spindle and 30-tool ATC. Travels are 600, 425, and 450 mm in X, Y, and Z axes, respectively.
EMAG claims to have originated the current multitasking concept with the 1998 introduction of a machine that performed both turning and grinding. Since then the company has used its modular machine platform to deliver equipment capable of integrating assembly, laser welding, and measurement with machining and grinding operations.
Gaining “done in one” capability may be the main enticement for manufacturers to switch to multitasking equipment, but there are several other benefits as well:
Space is one such valuable commodity on most shop floors these days. Companies are looking for machines to do complete machining on one platform.
Reconfigurability is another requirement. An example is the GMX 400 linear, a modular machine that can be configured with everything from an NC tailstock to a counter spindle, 12-station CNC turret with driven tools, and B axis with a swiveling range of ±120º and a 12,000-rpm spindle.
Quality is improved by limiting setups and transfers between machines. By far the most significant trend in any economy is the growth of productivity. A three-axis vertical machining center and a two-axis lathe increase productivity only marginally by delivering faster cycle times. However, there is no fundamental shift in the process–the increase in productivity equals the improvement in cycle time. Companies that can successfully raise quality, cost, and delivery at the same time are the ones truly improving. Multitasking machining technology is becoming popular because it can help manufacturers do just that.
- Indra
Category: Machining |
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