Vgrind 360E takes centre stage

Vollmer used its recent VDays event at the company’s world headquarters in Biberach, Germany to present its latest Vgrind 360E to over 400 customers that came from around the globe.

Introducing the new tool grinder, business development manager for the Vgrind 360 and Vgrind 360E, Andreas Weidenauer, discussed the benefits of the machine, which can process tools up to 100 mm in diameter, with a length of 360 mm. The presentation included an overview of the build quality that touched on the polymer concrete machine base for vibration absorption and reduced thermal expansion. With low thermal conductivity, the Vgrind 360E generates less thermal expansion throughout its robust 2100 kg structure.
Upon this base is the C-axis concept that provides the absorption and elimination of deformation and vibration through the top and bottom bearings in the twin grinding spindle configuration. Competitor machines with just a single bearing carry a higher risk of deformation and vibration, says Vollmer.
Underpinning the dynamics, kinematics and thermal stability of the Vgrind 360E, Vollmer has integrated an internal oil-based coolant cycle for cooling both the spindles and the motors. The temperature is maintained as a constant between the internal coolant oil cycle and the grinding coolant liquid due to a plate heat exchanger. This attention to detail increases the thermal stability of the Vgrind 360E and, as the oil runs through internal cooling cycles, the risk of damage or contamination through leakage is reduced.
The C and A axes have been configured with direct-drive torque motors to improve the dynamics of the Vgrind 360E. Indeed, the A-axis spindle rotates at a speed of 450 rpm as standard, with an optional 1000 rpm unit for specialist applications.
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Automated tool production on show

Informative technical presentations on Walter and Ewag tool grinding, erosion and laser processes – available in the UK from Walter Ewag UK – were among the array of technology treats displayed and discussed at the United Grinding Group’s three-day Grinding Symposium 2019 in Thun, Switzerland, where more than 1500 visitors attended.

Event mit Technologiepräsentationen

While Ewag focused on the use of lasers in online tool manufacturing, Walter highlighted both ‘high-end’ and PCD tool production. The potential benefits of Ewag’s Laser Line Ultra machine in the production of ultra-hard tools (solid carbide and PCD) for one customer were revealed as part of a novel Internet-based demonstration. After witnessing Ewag’s prototype demonstration at GrindTec 2018, when 200 tools were produced by the Laser Line Ultra, the customer established a cell around the machine where eight pallets accommodate a total of 1800 tools. Orders and production run autonomously with no operator involvement, round the clock if required.
The production of fir-tree milling cutters (HSS/carbide) for aerospace blade machining was outlined by Walter, using a cutter of 25 mm diameter and 40 mm long – and demanding a profile tolerance of ±2 µm – as an example. This demonstration showed the process integrity of the combined attributes of a Helitronic Power 400 tool grinding machine and a Helicheck 3D measuring machine, used for scanning a tool to create a 3D master model.
Walter also presented the effectiveness of integrating its ‘two-in-one’ Helicheck Power Diamond 400 grinding and erosion machine with the automated Helicheck Plus inspection machine for the production of PCD-tipped solid-carbide tools.
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Arrow scores bullseye with Studer grinder

The workforce at Hinckley-based Arrow Precision has access to a range of quality machine tools, helping the company’s connecting rods and crankshafts to deliver ultimate levels of performance. And now Arrow has one more: a Studer S41 CNC universal grinding machine supplied by Micronz.

The recently installed S41 is today fully operational across two shifts and, in some areas, is exceeding Arrow Precision’s expectations. For example, as the flexible machine can perform both external and internal precision grinding tasks – in addition to the external grinding of crankshafts journal and pins – the S41 is being used to grind internal features such as flywheel location bores. Crankshaft bores that previously took 30 minutes to grind on a manual machine now take less than 3 minutes. As well as producing high levels of surface finish on crank journals and pins, the Studer S41 is achieving sub-micron levels of diameter grinding accuracy.
Managing director Ian Arnold explains the reasons for the S41’s purchase: “As achieving the specified diameter and surface finish characteristics of crankshaft journals and pins constitutes the most critical crankshaft machining process, our new grinding machine needed to be of the highest possible technical standard. Also, as we manufacture crankshafts in series production and in short runs, we required a machine with great flexibility and quick changeover times.
“Not only has the exceptional speed and efficiency of our Studer CNC universal cylindrical grinder removed the possibility of production bottlenecks from our grinding department, the extra capacity it has created and additional capabilities it provides have opened-up further commercial opportunities.”
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Meeting increased demand with Ewag grinders

In response to the need for increased output by customers in the oil and gas and aerospace industries, Larkhall-based Gilmour Tools – one of the largest independently owned cutting tool manufacturers in Europe – has expanded its range of Ewag insert grinders with a Compact Line insert-grinding machine.

Supplied by Walter Ewag UK, a member of the United Grinding Group, the machine complements five other Ewag insert grinders (Ewamatic models) and has been installed primarily to produce threading-type inserts for the oil and gas sector.
According to managing director Gary Gilmour, the 5.5 kW/7000 rpm machine is suited to such work, offering fast and accurate insert machining. Its production capacity is not only enabling the company to meet increased order demands, but the machine also represents the latest upgrade to insert manufacturing at the 10,000 sq ft factory.
The Compact Line’s ‘three-in-one’ dressing unit is highlighted as especially useful, since it ensures grinding wheel concentricity and high process reproducibility, alongside wheel dressing, regeneration and ‘crushing’.
Gilmour Tools specialises
in the production of carbide inserts for all oil threads – to many complex shapes in a variety of materials – as well as the production of tool holders and blades.
Capable of machining carbide, cermet, ceramic and PCB/PCD inserts, the six-axis Ewag Compact Line provides resolutions of 0.0001 mm (linear) and 0.0001° (rotary). Depending on the clamping system, the machine can accommodate minimum inscribed circle diameters of 4 mm (pin clamping) and 3 mm (indexable insert clamping), and offers short set-up times, says the company.
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Rotary encoders help raise productivity

Swiss company Strausak AG, which produces CNC grinding machines for manufacturing and re-sharpening solid-carbide tools, wanted to offer customers the option to automate the loading and unloading of workpieces into and out of the spindle that rotates the workpiece in its U-Grind series machines.

The problem was that, to achieve high tool accuracy, an HSK 50 hydraulic expansion chuck with a diameter tolerance of only a few hundredths of a millimetre has to be employed, rather than a conventional collet with automation-friendly open tolerances.
To position the carbide blank or tool to the required level of precision, Strausak turned to robot manufacturer Stäubli, which now supplies the automation solution based on a compact, six-axis industrial robot. The position of each CNC rotary axis is controlled by a Heidenhain EQI 1100 absolute inductive rotary encoder with 18-bit resolution. Having reliable positional data fed back back to the NUM control on the U-Grind allows the robot gripper to manipulate the workpiece to within 50 µm.
Strausak’s managing director Alexandre Condrau says: “We were happy that Stäubli partners with Heidenhain for its rotary encoder requirements, as the compact dimensions of its inductive products suit our application. We also have CNC positioning of the swivelling grinding wheel head on our machines, and to achieve the necessary precision we use a Heidenhain ERA 4000 incremental angle encoder.”
Strausak sees further development possibilities that could help its customers even more. The company is currently working on programming the robot to re-grip the workpiece and readjust its insertion distance in the hydraulic chuck to enable the machining of very long tools, for instance.
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