A portal milling machine with linear drive achieves extremely high chip volumes/time of up to 4500cm3/min in aluminiumusing feedrates of up to 60m/min and spindle speeds up to 35,000 rev/min.
With the new FZ 38, Zimmermann-Boko is presenting a CNC portal milling machine with linear drive. The impressive dynamism of this machine bears witness to the highest level of compe-tency in the field of demanding drive technology. The aim Zimmermann is to offer optimum drive concepts for the specific requirements of their customers.

Towards this end, Zimmermann is making use of decades of experience at the peak of technological developments.

Current drive tech-nologies, such as linear motors, rack and pinion drive and ball screws are assessed objectively and customers profit from this: the result is comprehensive machine concepts with optimum drive for precisely defined employment pur-poses - an example of this is the FZ 38 with pure linear drive technology.

This is further proof that Zimmerman assimilate the individual requirements of each customer and focus their solutions accordingly - customer orientation of the highest quality.

F.

Zimmermann - the innovative company from Denkendorf near Stuttgart, Germany - offers state-of-the-art constructions for large-scale CNC portal milling machines and CNC plano-milling machines with high-speed technologies.

This year, the experts from Zimmerman will once again impress their target group at the trade show.

With the FZ 38, Zimmermann is pre-senting a CNC portal milling machine driven by linear motors that points the way to the future with its special qualities.

* Dynamism dimension 1 - exceptional efficiency - the most important aim when using linear drives is the increase in productivity.

The FZ 38 achieves extremely high time / chip volumes of up to 4500cm3/min (aluminium).

Feed rates on linear axes of up to 60m/min and spindle speeds of up to 35,000 rev/min make genuine HSC processing possible.

Just as im-pressive are the torque motors on rotational axes with feed rates of up to 150 deg/s.

The accuracy and surface quality realised in this way are decisive for this outstanding performance data.

And it is precisely in this point that the FZ 38 sets standards.

The linear drives achieve a very high level of standard control with a large Kv factor which also makes a low trailing distance and high po-sitioning accuracy possible even at high feed rates.

* Dynamism dimension 2 - well-established technical know-how - a prerequisite for the performance and accuracy values achieved with the FZ 38 lies primarily in a machine designed especially for using linear drives.

Zimmerman customers can profit here from exceptional empirical val-ues in the development of structurally stiff machines.

The solution lies in the combination of optimized lateral stands and torsion-free portal on the one hand and intelligent arrangement of the interfaces, i e, the drives on the other hand.

* Dynamism dimension 3 - high degree of economic efficiency - the overall economic efficiency of the FZ 38 is a result of the interplay of different aspects.

The high accuracy of the machine reduces manual work on finishing surfaces as far as possible or even avoids them entirely.

Due to the high feed rates, the ancillary times, e g, for reposi-tioning, tool orientation or tool change can be reduced.

The FZ 38 achieves very high levels of availability.

This is not least due to the contact-free, play- and wear-free and there-fore low-maintenance direct drives.

* Some technical details - construction method - as with all high-quality CNC portal milling machines from Zimmerman, with the FZ 38 we are dealing with a modularly constructed machine concept which allows different work areas, milling spindles and con-trol systems to be combined.

The machine has permanent lateral walls, a clamping table perma-nently connected to the foundation and an upper portal which moves in X-direction and is driven on both sides.

The workpiece is not moved.

The constantly moved masses (portal slide, cross slide and z-slide, milling head) ensure consistently dynamic behaviour - a prerequisite for optimum surface quality and the use of linear drives.

* Machine frame and guides - the machine bed is constructed from grey cast steel; lateral walls, portal and Z-slides are welded steel constructions.

The lateral walls are filled with a special compound material for dampening vibrations and stabilizing temperature.

The guides, drive and measuring systems on the X-, Y- and Z-axes are extensively protected against contamination or penetration by chips.

* Axis drive - irrespective of the make of the control system, all linear axes are equipped with the latest generation of Siemens digital linear motors.

At standstill, the machine is held in position by brake shoes on tes X- and Y-axes.

* Safety concept - if electricity fails, the Z-slide is effectively secured by powerful clamping heads and all axes are braked by the backfeed of the poten-tial energy through the effect of the generator.

* Cooling - the linear drives are uncoupled effectively from the machine by precision coolers with separate cooling cycles for magnet and motor ele-ments.

* Accuracy - the dynamism of the machine and the extreme inherent stiffness enable high levels of accuracy, in particular when finishing with high speeds and feed rates.

* The new VH 6 milling head with MuST technology - the new VH 6 milling head is especially designed for the HSC technology.

The drive of both rotation axes is carried out by backlash free torque motors.

With the high driving power the rotation axes can be used for simultaneous operations or they can be electronically fixed in position.

In addition, the two axes can be clamped hydraulically.

Both axes drives are designed following the Thermosandwichprinzip, and are equipped with a power and a supplementary precision cooling unit.

This drive technology enables a combination of precision, high driving power and increased dynamics.

In general two different spindles with various specifications are available for all application areas such as roughing, finishing and fine finishing.

* Universal spindle for all kinds of machining of aluminium, composites and light machining of cast iron and steel.

* Finishing spindle - high frequency spindle designed for finishing, for milling of fine contours and for fine finishing with highest surface quality.

Concerning flexibility Zimmermann came up with even more ideas.

Due to its modular design, the MuST system enables different configurations.

1 - One spindle is fixed in the milling head - however this can be changed manually as well.

2 - Semi-automatic spindle change system.

3 - Full automatic spindle change system - enables unmanned shifting * Areas of application - thanks to high stability and stiffness, constantly moved masses and highly dynamic linear drives as well as the spindle changing concept MuST, the FZ 38 is suitable for HSC work on all common materials in making tools, moulds and models as well as in the aircraft industry.

* Aluminium chipping with extreme feed rates.

* Compound materials.

* Overall processing of heavyweight materials such as steel, cast products and even titanium.

Conclusion - Zimmermann's strength is to offer efficient combinations of different machine concepts, drives, milling heads and spindle types.

Zimmermann is consistently enlarging its machine program and with its latest innovation, the FZ 38, it is now enriched by the ultimate high speed type dynamics and speed directly turn into benefit for our cus-tomers.

Rolf Roehm, Zimmermann sales and marketing director resumed: 'The perfect combination of machine design, tools, tool and work piece clamping devices, material technology parameters, the applica-tion know-how as well as the so called C-techniques has highest pri-ority when consulting our customers'.

'The development of the FZ 38 contributes a further option to the drive technique which is of great advantage to our customers.' * F Zimmermann will be exhibiting at IMTS 2006, Chicago, USA, September 6-13, Booth A-8568.