Threaded Grinding Wheel Phasing via Acoustic Emission Detection

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Solution Overview

Problem

Conventional phasing methods for grinding wheels struggle with precise detection of contact and non-contact with workpieces and dressers, leading to inefficiencies in grinding and dressing processes due to the instantaneous nature of acoustic emission detection.

Innovation Solution

A phasing method and device utilizing an acoustic emission fluid sensor to detect elastic waves generated during contact between a threaded grinding wheel and a dresser, adjusting the dresser's rotation number stepwise to ensure precise phasing by exceeding a predetermined value, allowing for high-precision contact detection and positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If acoustic emission detection is performed instantaneously to detect contact between grinding wheel and dresser, then the detection process is simple and fast, but the measurement precision is insufficient due to difficulty in precisely detecting contact or non-contact

Engineering Contradiction:
Improvedetection speedVSAvoidcontact detection precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies periodic action by rotating the dresser at multiple different rotation speeds (first rotation speed, second rotation speed, third rotation speed) to perform repeated measurements. This allows the system to collect multiple data points over time, transforming the instantaneous detection into a time-series measurement process that improves precision while maintaining operational efficiency.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent implements feedback by using the measured values from acoustic emission detection to determine whether contact has occurred, and then adjusting the dresser rotation speed accordingly. The system feeds back the measurement results to control the rotation speed adjustment, creating a closed-loop control system that enhances detection precision through iterative refinement.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If the dresser rotation speed is increased to improve detection sensitivity, then contact detection becomes more sensitive, but the system complexity increases due to need for rotation speed control

Engineering Contradiction:
Improvedetection sensitivityVSAvoidrotation control complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies dynamics by making the dresser rotation speed variable rather than fixed. The rotation speed is dynamically adjusted based on the measurement results - increasing when contact is detected and decreasing when no contact is detected. This dynamic adjustment optimizes detection sensitivity while adapting to different operational conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the rotation speed parameter of the dresser based on measurement outcomes. The system changes the rotation speed from a constant parameter to a variable parameter that adapts to the detection needs, thereby improving sensitivity without requiring complex additional hardware.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple measurements are performed at different rotation speeds to improve precision, then the measurement precision increases, but the loss of time increases due to multiple measurement cycles

Engineering Contradiction:
Improvephasing precisionVSAvoidphasing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies partial or excessive action by performing measurements at multiple rotation speeds (excessive measurements beyond a single measurement) to ensure high precision. The system deliberately performs more measurements than the minimum required, using the additional measurements to confirm contact detection accuracy, thereby prioritizing precision over speed.

Inventive Principle:
Principle #16Partial or excessive action

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 precise phasing of the threaded grinding wheel with the dresser, enhancing the detection sensitivity and accuracy of contact or non-contact, thereby improving the grinding and dressing processes.

Implementation Method 1

detecting, by means of an acoustic emission fluid sensor, elastic waves generated when one of thread surfaces of the threaded grinding wheel comes into contact with a corresponding one of blade surfaces of the dresser

Methodology Applied
Scientific EffectAcoustic emission: Acoustic Emission

Data Source

PatentEP2484489B1Method of phasing threaded grinding stone, as well as device therefor
Publication Date: 2018.10.31 MITSUBISHI HEAVY IND MACHINE TOOL CO LTD
  • EP2484489B1 patent drawingFigure 1
  • EP2484489B1 patent drawingFigure 2
  • EP2484489B1 patent drawingFigure 3

AI summary

Provided is a method of phasing a threaded grinding stone, as well as a device therefor, the aforementioned method and device being such that contact or non-contact of a threaded grinding stone with a disk dresser can be detected with high accuracy, with the result that the phasing of the threaded grinding stone can be accurately performed. For the purpose of achieving the above, a threaded grinding stone (14) is phased with respect to a disk dresser (32) prior to the engagement of the threaded grinding stone (14) with the disk dresser (32) during dressing. In performing this phasing, it is determined whether or not the threaded grinding stone (14) contacted the disk dresser (32), on the basis of a voltage (V) which is commensurate with the amplitude of the elastic wave generated in the threaded grinding stone (14) at the time when the threaded grinding stone (14) contacted the disk dresser (32). In a case where the voltage (V) does not exceed a threshold value (Vo) even if the threaded grinding stone (14) contacts the disk dresser (32), then the rotational speed of the disk dresser (32) is increased, with the result that there is forcibly created a situation where it is determined that contact occurred. Subsequently, the threaded grinding stone (14) is positioned, on the basis of the resulting phase thereof, in an intermediate phase where the aforementioned engagement is feasible.