Machine Tool Probe Positioning for Constant-Height Workpiece Measurement
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Solution Overview
Problem
Manual operation of the Z-axis feed shaft in machine tools for workpiece measurement is time-consuming and prone to inaccuracies due to the need for precise positioning and maintaining constant measurement point height, especially when workpiece side surfaces are not parallel to the Z-axis, and straightness errors of the Z-axis feed shaft can affect measurement precision.
Innovation Solution
A method that utilizes a control panel with jog buttons and an NC device to accurately and quickly position a measurement probe relative to a workpiece by setting Z-axis stroke limits and automatically storing measurement coordinates for subsequent automatic measurement, allowing for precise and efficient measurement of workpieces with reduced operator effort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If manual operation is used to position the measurement probe at multiple measurement points, then measurement flexibility is maintained, but measurement time increases and positioning accuracy deteriorates due to difficulty in maintaining constant height
Solution Approach 1:
The patent replaces manual mechanical operation of the jog dial with an automated system that uses the NC device to control feed shaft movement. The system automatically positions the measurement probe at predetermined Z-axis coordinates, eliminating the need for manual positioning while maintaining measurement precision through programmed coordinate control.
Solution Approach 2:
The patent implements preliminary action by pre-setting the Z-axis stroke limit and predetermined Z-axis coordinates before measurement begins. The NC device stores these coordinate values in advance, allowing the measurement probe to be quickly and accurately positioned at each measurement point without manual intervention during the actual measurement process.
2Ease of operation
If manual operation with jog dial is used to stop Z-axis feed shaft, then operator control is maintained, but operation complexity increases and time consumption increases due to need for precise positioning
Solution Approach 1:
The patent replaces the manual jog dial mechanical system with an NC device-based automated control system. The operator simply inputs the workpiece coordinate system origin, and the NC device automatically controls the feed shaft movement to position the measurement probe, dramatically reducing operation time while maintaining ease of use through simple coordinate input.
Solution Approach 2:
The system performs self-service by automatically calculating and positioning to measurement points based on the stored predetermined Z-axis coordinates. Once the origin is set, the NC device independently manages the positioning and measurement process without requiring continuous manual intervention, reducing both time consumption and operational complexity.
3Measurement precision
If manual positioning is used to maintain constant measurement point height, then measurement accuracy for non-parallel surfaces can be achieved, but operation time increases significantly
Solution Approach 1:
The patent replaces manual positioning operations with automated NC device control that uses predetermined Z-axis coordinates stored in memory. This substitution maintains measurement accuracy for non-parallel surfaces by precisely controlling the measurement probe height while dramatically improving productivity through automated positioning at each measurement point.
Solution Approach 2:
The system changes the operational parameter from manual height adjustment to automated coordinate-based positioning. By storing predetermined Z-axis coordinates that account for varying measurement point heights, the system maintains measurement accuracy while improving efficiency through automated parameter control rather than manual adjustment.
4Productivity
If Z-axis stroke limit is set and automatic positioning is used, then measurement speed increases and operator effort decreases, but system complexity increases
Solution Approach 1:
The patent applies universality by utilizing the existing NC device, which is already present in the machine tool, to perform both machining control and measurement positioning functions. The NC device's existing memory and coordinate system capabilities are leveraged for storing predetermined Z-axis coordinates and managing automatic positioning, avoiding the need for separate dedicated measurement equipment and reducing overall system complexity.
Data Source
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AI summary
Disclosed is a workpiece measurement method for determining the position of a workpiece (W) on a machine tool (100) based on feed shaft coordinates when a probe (114) and the workpiece contact each other, in which the probe and the workpiece are moved relative to each other by a plurality of feed shafts. The method includes the steps of moving one of the plurality of feed shafts to a desired measurement position, storing coordinate values of the one feed shaft at the desired measurement position, moving the probe and the workpiece relative to each other by means of the one feed shaft and another feed shaft, stopping the movement by the one feed shaft when the stored coordinate values have been reached, and measuring the workpiece at a plurality of measurement points by moving the probe using the other feed shaft in a state in which the one feed shaft is stopped at the coordinate values.