Job Shop Optimizes Precision Production with Turning

March 24, 2011
A series of EMCO machines work well together as they produce thousands of parts every week
Simultaneous turning work is possible using both turrets on the main or counter spindle.
Brisker GmbH, a job shop in Vienna, Austria, uses multiple EMCO Maier turning machines to produce thousands of parts every week. "Our machine hall is designed and planned down to the very last corner," explained Johann Brisker, "which means that a compact machine footprint is always one of our key criteria."

You may call Brisker GmbH a job shop. After all, the 60-year-old machining operation in Vienna, Austria, was established to perform traditional metalworking and machining, and it continues to supply components to virtually any industrial sector. Under current president Johan Brisker though, the 800-m2 shop is specializing in precision turning and milling.

In particular, Brisker GmbH produces small parts or “microparts” in all standard materials (stainless steel, aluminum, titanium) in series that range from 50 to 5,000 pieces. With 25 workers, the also handles complete assembly of individual components, per custom order.

With this market strategy, Brisker GmbH has a series of demands for the machines it selects. They must offer:
• High productivity for series production
• Complete bar-stock machining capability
• Y-axis and driven tools
• Compatibility with existing tool holders
• Interchangeability of existing clamping devices
• Compact dimensions, including a short bar loader
• Compatibility with Siemens controls, which drive the existing machines; and
• Competent, and reliable customer service by the machine builder.

The Viennese shop’s choice is EMCO, another Austrian company and one of Europe's top builders of machine tools. "For this range of parts in particular, there is simply no comparable two-spindle machine on the market that offers such a high level of precision from such a small footprint," Johann Brisker said of the selection.

A committed customer
Particularly in regard to turning operations, machine shops today are determined to manufacture parts in line with the current state-of-the-art machine designs. For that reason, Johann Brisker bought the shop’s first EMCOTURN 320 in 1987. He explained that the choice was so satisfactory that he went on to purchase nine EMCOTURN 332 with counter spindles and two turrets.

All of Brisker’s turning machines are automated with (short) bar loaders in order to meet the production-cost requirements.

Over the years, EMCO and Brisker GmbH came to view each other as partners: "Since we work relatively closely with EMCO, we often see ideas that originate from our longstanding experience in the manufacture of precision turning parts being incorporated into the new machine models manufactured by EMCO. This is something of which we are particularly proud," observed Johann Brisker. In 2009, when the shop needed an additional CNC lathe for a specific size of parts, it approached EMCO with its particular needs. Because of the positive experience of "complete machining" with two HYPERTURN 665s from EMCO, Brisker decided that the most important criterion was complete machining from bar stock.

Although the CNC market offers only a few models that match this request, especially at the smaller end of the parts spectrum, EMCO had recently introduced its HYPERTURN 45, which provided the ideal solution for the range of parts that Brisker had to machine. This new, counter-spindle machine features two turrets, driven tools on both turrets and a Y-axis, all combined in an extremely space-saving form.

A look around the Brisker shop reveals the importance of the latter factor. "Our machine hall is designed and planned down to the very last corner," explained Johann Brisker, "which means that a compact machine footprint is always one of our key criteria."

An extension of this point is the importance of machine program compatibility at Brisker GmbH, which is why the shop remains determined to use the same or related machine designs with the same control technology. Because Brisker continues to use workshop programming for turning, there are certain benefits to the flexibility of the machine pool. However, this was not the only reason why Johann Brisker selected the HYPERTURN 45. He also was impressed by the hard technical data. (See the table below.)

Increasing productivity through technology
The most striking aspect of the HYPERTURN 45 is its compact construction, which conceals a surprising degree of technology: high-performance main and counter spindles, two turrets for up to 12 tool adapters, water-cooled, integrated spindle motors, dynamic digital drives, and thermo-symmetrical machine construction. One notable advantage of the HYPERTURN 45 over the EMCOTURN 332 is a Y-axis with a 70-mm traverse path in the upper slide system and a Z2-axis in the lower slide system. As with the HYPERTURN 645/665, the main and counter spindles are equipped with integrated, water-cooled spindle motors, with drive power of 15 kW, a maximum speed of 7,000 rpm, and torque of 100 Nm.

"The high dynamics mean that we have to install harder vibration dampers and screw the machine to the floor at four points, rather than just two," explains the company president.

The spindle length of the HYPERTURN 45 was adjusted to match the short loader magazine. "It can process the typical bar stock of 1m without the need for an additional support," said EMCO sales engineer Gerhard Nebohy.

The large dimensions of the counter-spindle connection with A2-5 allow the counter spindle to be used to remove barstock parts with a diameter of up to 45 mm, while the latest control and drive system, Siemens 840D-sl (solution line), makes the machine quick and easy to program. Coupled with the Esprit CAM software by DP Technology, the HYPERTURN 45 becomes a high-tech production center with 3D simulation.

Johann Brisker also has a specific example to demonstrate the system's outstanding technical performance: Complete machining of a workpiece with a high level of milling content (approximately 50 percent) on the EMCOTURN 332 lasts around three minutes, which is already a good time. Without any program optimization, the HYPERTURN 45 has already reduced this machining time to less than two minutes — representing an improvement of around 35 percent.

"For parts with a large number of turning operations, the average increase in productivity is 20 percent,” Brisker said. “This has been achieved solely through the significantly higher dynamics, faster rapid traverses, and reduced tool changing times."

Johann Brisker singled out the ergonomics and design of the system for attention: "Ergonomic considerations in particular, such as locating the spindle and turret within easy reach of the machine operator, are essential for fatigue-free operation. The EMCO design is extremely well thought out in this regard."

He also is quite pleased with the service reliability and after-sales support provided by EMCO: "It's one of the main reasons we decided on EMCO. The availability of spare parts and the company's response times are exemplary,” he said.

"We don't just blindly buy EMCO out of habit,” Brisker assured. “We also use CNC machines from other manufacturers. However, for this range of parts in particular, there is simply no comparable two-spindle machine on the market that offers such a high level of precision from such a small footprint."

"Our customers aren't just interested in increasing productivity,” observed Gerhard Meisl, EMCO senior product manager. They also want backward compatibility with existing NC programs and often have large quantities of tool holders and clamping devices that need to be reused.”

Technical data

Work area

Swing over bed Ø430 mm Swing over cross-slide Ø300 mm Distance from main spindle to counter spindle 720 mm Maximum turning diameter Ø300 mm Maximum part length 480 mm Maximum bar capacity Ø45 (51) mm

Slide traverse paths in X / X2 160 / 150 mm
Slide traverse paths in Z / Z2 / Z3 510 / 510 / 510 mm
Slide traverse paths in Y +40 / -30 mm

Main spindle
Speed range 0-7000 rpm
Max. spindle torque 100 Nm
Spindle nose DIN 55026 A2-5
Spindle bearing (inner diameter) Ø85 mm
Spindle bore Ø53 mm

Counter spindle
Speed range 0-7000 rpm
Max. spindle torque 100 Nm
Spindle nose DIN 55026 A2-5
Spindle bearing (inner diameter) Ø85 mm
Spindle bore Ø53 mm

C axes
Circular axis resolution 0.001°
Rapid speed 1,000 rpm
Spindle indexing (disc brake) 0.01°

Drive performance
Main spindle 15 kW
Counter spindle 15 kW
Tool turrets 1+2
Number of tool stations 2×12
VDI shaft (DIN 69880) VDI 25
Tool cross-section for square tools 16×16 mm
Shank diameter for boring bars Ø25 mm
Turret indexing time 0.2 sec
Driven tools 1+2
Speed range 0-6000 rpm
Torque 16 Nm
Drive power 4 kW
Number of driven tools 2×12

Feed drive
Rapid speed ×/ Y / Z 30 / 15 / 45 m/min
Feed force in the X axes/Y axis 4000 N
Feed force in the Z axes 5000 N
Feed force in the Z axis counter spindle 6000 N
Position variation Ps (VDI 3441) ×/ Y / Z 3 / 3 / 3 μm

Coolant system
Tank capacity 200 l
Coolant pressure/delivery 0.62 (1.1) kW
Pump capacity at 3.5 bar/1 bar 12.5/58 l/min
Pump capacity at 10 bar/5 bar (optional) 15/40 l/min

Power consumption
Connected load 30 kVA
Supply pressure 6 bar

Height of centers above floor 1,126 mm
Machine height 1985 mm
Machine footprint W×D 2650×1950 mm
(without chip conveyor and cooling unit)
Total weight of machine 4,200 kg
Safety devices CE compliant

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