Cutting Tool Displacement Correction Using Reference Body Thermal Expansion
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Solution Overview
Problem
Conventional techniques face challenges in accurately measuring the displacement and wear of cutting tools due to heat displacement errors and complex configurations, especially when dealing with inner and outer diameter tool bits, which affect measurement accuracy and require complex mechanisms for imaging.
Innovation Solution
A measuring apparatus and method that uses a reference body for heat displacement correction, imaging both tool bits in the same area, and a cutting machine with an imaging system that separates optical paths to image different positions simultaneously, allowing for accurate temperature measurement and displacement correction of cutting tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a camera is used to image a cutting tool for measuring wear or displacement, then the measurement can be performed visually, but heat displacement of the camera and camera holding bracket reduces measurement accuracy
Solution Approach 1:
A reference body with a known thermal expansion coefficient is introduced as an intermediary between the camera and the cutting tool. The reference body is imaged together with the cutting tool, and its known displacement due to thermal expansion is used to calculate and correct the heat displacement of the camera system, thereby maintaining measurement accuracy.
Solution Approach 2:
The reference body creates a reference image that copies the thermal displacement characteristics of the camera system. By comparing the position changes of features on the reference body in reference and measurement images, the camera's heat displacement is quantified and used to correct the cutting tool measurements.
2Measurement precision
If the camera is positioned closer to the cutting tool to improve measurement resolution, then measurement precision improves, but the field of view decreases making it difficult to image both reference gauges and chips
Solution Approach 1:
The reference body is designed with features arranged in multiple dimensions, allowing the camera to capture both reference gauge information and chip information in the same field of view. The reference body includes a first feature at a first position and a second feature at a second position, enabling multi-point measurement within a compact space.
3Measurement precision
If separate reference gauges are arranged for inner diameter and outer diameter tool bits, then each tool bit can be measured accurately, but the mechanism complexity increases
Solution Approach 1:
A single reference body is designed to serve multiple functions: it provides reference information for both inner diameter and outer diameter tool bits, and enables imaging of both tool bit types in the same field of view. The reference body includes features that work with different tool bit configurations, eliminating the need for separate reference gauges.
4Measurement precision
If the camera images different types of tool bits at different positions, then each tool bit can be imaged clearly, but simultaneous imaging of multiple tool bits becomes difficult
Solution Approach 1:
The reference body is segmented into multiple features positioned at different locations, with each feature corresponding to a specific tool bit type or position. This segmentation allows the camera to capture reference information for multiple tool bits simultaneously in a single image, improving productivity while maintaining imaging clarity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables accurate measurement and correction of cutting tool displacement and temperature, improving processing accuracy by simplifying the configuration and eliminating the need for complex mechanisms, while allowing for simultaneous imaging of different tool bits.
Implementation Method 1
an imaging means for imaging the reference body and the object to be measured in a same imaging area
Implementation Method 2
image data in a transmitted light quantity of a lens positioned at a predetermined position
Implementation Method 3
a reference body which is a reference of a heat displacement amount of a heat-displaced object to be measured
Implementation Method 4
measuring an expansion coefficient or the like of a sample whose expansion coefficient or contraction coefficient is unclear
Data Source
AI summary
Provided is an apparatus and a method thereof which can detect a displacement amount of a cutting tool with respect to a workpiece with high accuracy and can correct a processing position with high accuracy. Accordingly, a turret gauge 46 is comprised of an invar body 47 and a gauge main body 48 with a different thermal expansion coefficient. A point A of the gauge main body 48 and a leading edge 47A of the invar body are imaged in a state of viewing the whole thereof at a time of an initialization and a calibration cycle (CS), and a temperature of the gauge main body 48 is detected by comparing each image data. Furthermore, the length between the point A and a point B of the gauge main body 48 at the time of the CS is obtained based on the image data. The actual length is compared with a theoretical length between the point A and the point B at a temperature of the gauge main body 48 at the time of the CS, and consideration is given to the comparison. Therefore, a heat displacement amount of a ball screw can be accurately detected, the displacement of a processing position of a cutting tool can be corrected with high accuracy, and processing accuracy of a workpiece can be improved.