Product category:
5-axis (3+2 axes and continuous path) machining centres
News Release from: Emag UK | Subject: BA S03 vertical machining centre
Edited by the Manufacturingtalk Editorial
Team on 29 August 2007
Five-axis twin-spindle VMC has high
output
The aerospace industry wants more 5-axis production machining output, which is why a German machine tool builder has introduced a twin-spindle, 5-axis vertical and horizontal machining centres.
Five-axis machining is now common practice when machining complex components such as turbine casings, impellers, bladed disks (or BLISKs) and ends There is also an increasing trend of using production 5-axis machining in the automotive industry
This article was originally published on Manufacturingtalk on 12 Nov 2001 at 8.00am (UK)
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Conventional single-spindle machining centres are more often now not considered to be an economical proposition, owing to the larger batch sizes involved.
The German machine tool builder, Schwaebische Werkzeugmaschinen (SW), is therefore offering twin-spindle machining centres, the BA S03 vertical machining centre (VMC) and the BA W04 and BA W06 horizontal machining centres (HMC).
In a report to Manufacturingtalk from Emag, SW said the machines have been designed to cover most of mass production, 5-axis machining requirements.
Further reading
EMAG UK - a company profile
Since its foundation in 1984, EMAG UK has established a strong position in the UK automotive market supplying CNC multi-functional production centres.
Turrets feed vertical shaft turning centre
Following on from its earlier horizontal shaft turning machine, Emag has developed a vertical shaft turning machine using two turrets to exchange workpieces as well as perform machining.
Grinding and automation expertise extended
With the integration of Ingersoll Naxos crankshaft grinding machine company into the Emag Group, systems can be developed in conjunction with Karstens, Reinecker, Kopp and Heilig Automation.
Simultaneous 5-axis machining has gained widespread acceptance in the automotive industry and its subcontractors over the last few years.
Note that 5-axis milling makes great demands on the dynamics and precision of a machine, met by the design and specification of SW's 5-axis machining centres.
* Monobloc structure - the design of the BA S03 VMC is of a monobloc construction - enclosed on three sides and topped by a travelling gantry.
It combines a minimal footprint, extreme rigidity and the greatest possible protection of guideways and drive components against the ingress of chip particles and coolant.
The box-in-box design of the 3-axis unit further increases the degree of rigidity.
The BA S03 features ball screw drives in the linear drives and direct drives in the rotary axes.
The torque drives guarantee backlash-free operation.
A gantry drive in the Y-axis ensures an absolutely parallel movement of the slide, even where cutting exert off-centre forces.
The direct drives for the swivel axes, in conjunction with direct measuring systems, offer a positioning accuracy of +/-5 angular seconds.
This ensures that the positioning accuracy Tp achieved in the whole of the machining area of the BA S03 is 0.01mm, according to the VDI DGQ 3441 standard.
The acceleration of up to 10m/s2, linear axis speeds of max 75m/min and rotary axis speeds of up to 50 rev/min ensure that idle times are kept to a minimum.
* Two spindles double production - SW has been building twin-spindle, 5-axis machining centres since the middle of 2004.
For example, they are used increasingly in the machining of turbochargers, owing to the hefty demand for diesel engines.
"Our twin-spindle solution gives us a great advantage over the single-spindle process, especially when it comes to the manufacture of impellors, which calls for relatively few tools.
All it usually involves is between three and five tool changes," said Erik Pfeiffer, manager of technological developments at Schwaebische Werkzeugmaschinen.
"With the SW chuck the workpieces are quickly loaded and unloaded.
It all results in very short idle times.
In fact, the twin-spindle design of the BA S03 allows us to double production".
The twin-spindle design has no adverse effects on programming, as both Z-axes are controlled by identical departure commands, so that only one spindle has to be programmed - just as on a single-spindle machining centre.
"Although it allows us to almost double production, the setup effort is about 50% of that for two single-spindle machining centres," said Pfeiffer.
Small batch production using twin-spindles - there also are viable applications of twin-spindle machining centes in small batch production.
Where parts are milled from solid stock, the raw material (e g, aluminium or titanium) is usually held in two concentrically clamping universal chucks.
This arrangement makes resetting easier and quicker, said SW, as all component variants can be clamped in the same chuck.
Idle times can be ignored, as the machining process itself is a long operation.
"The cycle times of complex components, especially in titanium, can be in the tens of minutes or even hours.
A much more pertinent question is how to increase the output per machine.
This can be done with a twin-spindle machining centre.
With a batch size of 10 components and a cycle time of one hour per component, it makes a great deal of a difference whether the machine will yield one component per hour or two," according to Pfeiffer.
* 3D simulation ensures accurate cycle times prediction - to be able to arrive at a cycle time that is as accurate as possible and to generate and optimise the NC program in the early stages of a project, SW employs the 3D machine simulation system eM RealNC for its 5-axis machining operations.
All NC axes parameters (speed, acceleration, jerk rate, V-constant, etc.) are included for the purpose.
In the same way, all movements of the chain-type tool magazine are simulated, to be able to assess the time taken for tool changes as accurately as possible.
Canned cycles and subroutines are also displayed.
The user finds a sense of security in being able to look at possible collision factors and can also reduce idle times.
The result of simulation will be realistic cycle times, providing a basis for optimal capacity planning before a single chip has been generated.
Therefore, simulation reduces machining cycle 'run-in' times.
* Emag and SW at EMO 2007, Hannover, Germany, September 17-22, Hall 12, Stand D47. Request a free brochure from Emag UK ...
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