In order to reduce friction of a crank shaft during operation by a large amount with low complexity through structuring sliding bearing surfaces (1) of the crank shaft through controlled introduction of microscopically small indentations (27) it is proposed for the center bearings and the crank bearings to only structure highly loaded portions of the bearing surface in circumferential direction and also in axial direction since this is already difficult to achieve in view of the operating gap towards the tool that only has a size of a few m.

In order to reduce friction of a crank shaft during operation by a large amount with low complexity through structuring sliding bearing surfaces (1) of the crank shaft through controlled introduction of microscopically small indentations (27) it is proposed for the center bearings and the crank bearings to only structure highly loaded portions of the bearing surface in circumferential direction and also in axial direction since this is already difficult to achieve in view of the operating gap towards the tool that only has a size of a few m.

An electric discharge machine is provided. The electric discharge machine includes: an axis drive part moving a tool electrode in at least one axial direction; and a sensor unit detecting a linear movement position of the axis drive part in the axial direction. The sensor unit includes a measurement scale having a linear shape, a position detector scanning the measurement scale and obtaining position information, and a pair of adjustment blocks fixed to both ends of the measurement scale or the position detector and erected perpendicular to an extension direction of the measurement scale. The adjustment blocks are fixed to the axis drive part and are curved in the axial direction due to a temperature change.

An electric discharge machine is provided. The electric discharge machine includes: an axis drive part moving a tool electrode in at least one axial direction; and a sensor unit detecting a linear movement position of the axis drive part in the axial direction. The sensor unit includes a measurement scale having a linear shape, a position detector scanning the measurement scale and obtaining position information, and a pair of adjustment blocks fixed to both ends of the measurement scale or the position detector and erected perpendicular to an extension direction of the measurement scale. The adjustment blocks are fixed to the axis drive part and are curved in the axial direction due to a temperature change.

A method of polishing a surface of an object disposed within a gas chamber is provided. The method includes filling the gas chamber with a discharging medium to a predefined pressure, applying a voltage between an electrode and the surface, calibrating a height of the electrode relative to the surface so as to establish electrical breakdown threshold criteria, and scanning the electrode with respect to the surface so as to sequentially position the electrode over a plurality of locations on the surface, each location characterized by a surface error. When a respective location in the plurality of locations has a surface error that meets the electrical breakdown threshold criteria, electrical breakdown occurs, whereby the electrical breakdown results in a discharging pulse that polishes the surface.

A manufacturing method is provided during which a workpiece is electrical discharge machined using an electrode to form an aperture in the workpiece. A first voltage is measured indicative of a gap voltage between the electrode and the workpiece using a first measurement device to provide a first measurement signal indicative of the first voltage. Movement of the electrode is controlled using the first measurement signal. A second voltage is measured indicative of the gap voltage using a second measurement device to provide a second measurement signal indicative of the second voltage. A determination is made whether the electrode has broken through the workpiece using the second measurement signal.

A manufacturing method is provided during which a workpiece is electrical discharge machined using an electrode to form an aperture in the workpiece. A first voltage is measured indicative of a gap voltage between the electrode and the workpiece using a first measurement device to provide a first measurement signal indicative of the first voltage. Movement of the electrode is controlled using the first measurement signal. A second voltage is measured indicative of the gap voltage using a second measurement device to provide a second measurement signal indicative of the second voltage. A determination is made whether the electrode has broken through the workpiece using the second measurement signal.

A method of polishing a surface of an object disposed within a gas chamber is provided. The method includes filling the gas chamber with a discharging medium to a predefined pressure, applying a voltage between an electrode and the surface, calibrating a height of the electrode relative to the surface so as to establish electrical breakdown threshold criteria, and scanning the electrode with respect to the surface so as to sequentially position the electrode over a plurality of locations on the surface, each location characterized by a surface error. When a respective location in the plurality of locations has a surface error that meets the electrical breakdown threshold criteria, electrical breakdown occurs, whereby the electrical breakdown results in a discharging pulse that polishes the surface.

A method of polishing a surface of an object disposed within a gas chamber is provided. The method includes filling the gas chamber with a discharging medium to a predefined pressure, applying a voltage between an electrode and the surface, calibrating a height of the electrode relative to the surface so as to establish electrical breakdown threshold criteria, and scanning the electrode with respect to the surface so as to sequentially position the electrode over a plurality of locations on the surface, each location characterized by a surface error. When a respective location in the plurality of locations has a surface error that meets the electrical breakdown threshold criteria, electrical breakdown occurs, whereby the electrical breakdown results in a discharging pulse that polishes the surface.

A gap detection apparatus for determining in real time the gap required for electrochemical machining gap includes a tooling electrode, a plurality of tool adjusting electrodes, a feedback circuit, a processing feed mechanism for controlling the tooling electrode, a three-dimensional driving mechanism, and an automatic control and measurement system. The tooling electrode includes a plurality of through-holes for receiving tool adjusting electrodes. The three-dimensional driving mechanism is mounted upon the processing feed mechanism, which includes a Z-coordinate feeding portion having a thimble for the feeding of the tool adjusting electrodes. The automatic control and measurement system controls the feed of the processing feed mechanism and the three-dimensional driving mechanism, and establishes the required gap for electrochemical machining.