Integrated dressing with wire erosion

With Studer-WireDress® Fritz Studer AG brings a brand new dressing device to the market, which uses the wire erosion principle and is completely integrated into the grinding machine and its control system. The grinding wheel never has to be removed for dressing. Thanks to the high proportion of grain space, the wheel is very free cutting. This allows much more grinding oil to enter the grinding slot, enabling a high feed with less workpiece deflection. The dressing intervals can be longer. However, as the dressing process requires so little expense and effort, very complex contours can also be dressed at shorter intervals. As the user can fully utilise the advantages of metal-bonded grinding wheels during rough and fine grinding, the Studer-WireDress® dressing system pays for itself in less than a year.

The dressing device is a small wire erosion machine in principle. The electrode is a wire, which is drawn with a small gap tangentially past the machining point at a constant speed of 100 millimeters per second. The opposite pole is the grinding wheel, which moves at peripheral speeds of 50 to 140 metres per second during dressing. It does not need any dielectric, as the grinding oil used during grinding fulfills this function. The dressing wire is guided in a groove on the circumference of a thin, circular ceramic disk. The ceramic disk has a notch at the point where the sparks jump between the wire and the grinding wheel.

Feeds of 15 to 25mm/min can be achieved when dressing a typical metal bond. In this way largely free geometries and intricate contours with internal radii of 0.2mm and external radii of 0.05mm are generated on the grinding wheel. Removal rates of up to 80mm3/min are achieved. The grain retains its original shape during this contactless dressing process.

No wear on the dressing toolAs the wire is continuously advanced during the dressing process, an electrode with precise geometry is always located at the dressing position.

The wire reel in the dressing unit contains ten kilometers of wire; this supply would allow dressing to be continued for approximately 16 hours without interruption. The used wire is cut into short pieces immediately after the dressing process and collected in a container. The ceramic guide disk across which the electrode wire runs is extremely resistant and only wears after several hundred hours. The circumference of the disk has three of the abovementioned notches; if necessary it is simply turned further round by one of the three segments and an intact wire guide is available again.

Control unit integrated into the grinding machine control systemThe STuder-WireDress® control unit is integrated into the control system of the grinding machine. It has all necessary dressing functionalities and also contains a software programme for intelligent profiling with path optimization (StuderDress integrated). The grinder does not need any special training to operate the dressing device, as he is guided by the clear and transparent guidelines on the screen of the control unit.

The new development also brings significant energy savings as part of the Blue Competence measures at Studer. It only needs around 500 watts during dressing, and just 25 watts during the standby phases. For comparison rotary dressing with diamond wheels uses 1.5 kilowatts and the energy required for the provision of sealing air, which is constantly necessary, is 1kW.

For more information contact Retecon Machine Tools on TEL: 011 976 8600 or visit www.retecon.co.za