Finishing method and finishing machine for measurement-assisted finishing of bores

A finishing method for material-removing finishing of a bore in a workpiece on a finishing machine, wherein a finishing tool removes material from the inner surface of the bore in a finishing operation and a shape measurement of the inner surface of the bore is performed on the finishing machine before, during and/or after the finishing operation, the method comprising introducing a measuring tool into the bore and generating a relative movement between the measuring tool and the workpiece,

• detecting geometry-relevant measurement values by the measuring tool, and
• evaluating the measurement values in an evaluation operation to ascertain at least one shape measurement value describes the macro shape of the bore inner surface,
• wherein the evaluation operation comprises:
• filtering the measurement values generated by the measuring tool using a filter criterion and at least one filter parameter to ascertain filtered measurement values;
• performing a curve fitting on the filtered measurement values to ascertain at least one fitting element adapted to the filtered measurement values in a reference element selected from the group consisting of reference circle, reference line, reference cylinder, reference cone, reference sphere and a combination of rotationally symmetrical portions of at least two of the reference elements;
• ascertaining the shape measurement value using at least one geometric property of the fitting element;
• and
• further processing the shape measurement value to operate the finishing machine.

A finishing machine that finishes a bore in a workpiece comprising:

• at least one work station having a tool carrier that carries a tool and a workpiece holding device that holds the workpiece in a working position of the work station;
• a control device that controls working movements of the tool carrier and/or the workpiece holding device;
• a measuring system that performs a shape measurement of the bore inner surface, wherein the measuring system has a measuring tool that can be inserted into the bore for detecting geometry-relevant measurement values, and the measuring tool is coupled or can be coupled to the tool carrier and can be moved relative to the workpiece by generating a relative movement between the measuring tool and the workpiece carrier;
• and
• an evaluation device that evaluates the measurement values detected by the measuring tool in an evaluation operation to ascertain at least one shape measurement value describing the macro shape of the bore inner surface;
• wherein the evaluation device is configured in at least one evaluation mode to perform steps in an evaluation operation:
• filtering the measurement values generated by the measuring tool using a predefined or predefinable filter criterion to ascertain filtered measurement values;
• performing a curve fitting on the filtered measurement values to ascertain at least one fitting element adapted to the filtered measurement values in a reference element, at least one selected from the group consisting of reference circle, reference line, reference cylinder, reference cone, reference sphere and a combination of rotationally symmetrical portions from at least two of the reference elements;
• ascertaining the shape measurement value using at least one geometric property of the fitting element;
• and
• processing the shape measurement value to operate the finishing machine.