Workpiece Spindle Headstock Position Correction During Machining

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Solution Overview

Problem

The relative position between a workpiece and a machining body in a machine tool with a movable workpiece spindle headstock cannot be accurately corrected due to variations in the position of the movable workpiece spindle headstock during machining, leading to insufficient correction accuracy.

Innovation Solution

A method involving a moving process to position the movable workpiece spindle headstock, calculating positional deviations, and correcting these deviations using a feed mechanism unit, with optional reference object and measurement sensor attachments to ensure accurate relative positioning between the workpiece and machining body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a reference ball is attached to the workpiece spindle and a touch probe is used to measure its position, then the relative position between workpiece and tool can be corrected, but the correction accuracy is insufficient when the workpiece spindle headstock is movable because the headstock position varies during machining

Engineering Contradiction:
Improvecorrection accuracyVSAvoidposition stability of workpiece spindle headstock
Core Design Contradiction:
Measurement precisionVSStability of the object's composition

Solution Approach 1:

The patent measures the positional deviation of the reference ball before machining begins, when the movable workpiece spindle headstock is positioned at a predetermined location. This preliminary measurement captures the deviation in the exact position where machining will occur, ensuring that the correction data corresponds to the actual machining conditions. The measured deviation is then used to correct the workpiece coordinate system before machining starts, eliminating the problem of position variation during machining.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the movable workpiece spindle headstock is repositioned according to workpiece size, then different workpiece sizes can be accommodated, but the relative position correction becomes inaccurate because the headstock position changes between measurement and machining

Engineering Contradiction:
Improveworkpiece size adaptabilityVSAvoidrelative position accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent measures the positional deviation of the reference ball at the specific position where machining will actually occur, rather than at a fixed reference position. By measuring at the predetermined position corresponding to the actual machining location, the system captures the deviation parameters (X and Y coordinates) that are relevant to the specific workpiece size and machining operation. This allows accurate correction for different workpiece sizes while maintaining relative position accuracy.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4592778A1Correction method for relative position of workpiece and machining body that machines said workpiece
Publication Date: 2025.07.30 DMG MORI CO LTD
  • EP4592778A1 patent drawingFigure 1
  • EP4592778A1 patent drawingFigure 2~3
  • EP4592778A1 patent drawingFigure 4

AI summary

There is provided a correction method that enables highly accurate correction of a relative position between a workpiece and a machining body during machining of the workpiece in a machine tool including a movable workpiece spindle headstock capable of moving in a predetermined direction. A deviation amount in a relative position between a workpiece spindle (11) mounted on the movable workpiece spindle headstock (4) and a machining body holding unit (7) is calculated after the movable workpiece spindle headstock (4) is moved to an intended usage position for machining of the workpiece, a deviation amount in the relative position between the workpiece (W) and the machining body (T) during machining of the workpiece is estimated based on the calculated deviation amount, and a feed mechanism unit is controlled so as to correct the estimated deviation amount.