Complex Lathe Spindle Angle Correction via Two-Speed Contact Sensing

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Solution Overview

Problem

Existing methods for detecting the position and posture of a workpiece in a tool machine using a detection jig struggle to set an optimal contact speed, balancing detection accuracy and productivity, especially in complex lathes performing drilling or planar processing, where the spindle rotation angle needs to be accurately detected.

Innovation Solution

A method involving two contact speeds is implemented, where a first speed is set for initial contact and a second, slower speed for accurate detection, allowing for precise spindle angle correction, with a device comprising a tool post movement member, spindle rotation member, contact detection member, and correction value calculation unit to manage the contact operations and calculate correction values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the contact speed is set to a slow speed to improve detection accuracy, then the detection accuracy is improved, but the productivity is degraded due to increased detection time

Engineering Contradiction:
Improvedetection accuracyVSAvoidproductivity
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The contact operation is divided into two distinct phases: a first contact operation at a first speed and a second contact operation at a second speed. This segmentation allows each phase to be optimized for its specific purpose, resolving the contradiction between speed and accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact speed is made dynamic rather than static, with the system automatically switching between a first speed and a second speed based on the detection phase. This dynamic adjustment allows the system to achieve both high accuracy and high productivity

Inventive Principle:
Principle #15Dynamics

2Productivity

If the contact speed is set to a fast speed to improve productivity, then the productivity is improved, but the detection accuracy becomes degraded and impact sound becomes louder

Engineering Contradiction:
ImproveproductivityVSAvoiddetection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The contact operation is divided into two distinct phases: a first contact operation at a first speed and a second contact operation at a second speed. This segmentation allows each phase to be optimized for its specific purpose, resolving the contradiction between speed and accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact speed is made dynamic rather than static, with the system automatically switching between a first speed and a second speed based on the detection phase. This dynamic adjustment allows the system to achieve both high accuracy and high productivity

Inventive Principle:
Principle #15Dynamics

3Productivity

If the contact speed is set to a fast speed to improve productivity, then the productivity is improved, but the impact sound becomes louder causing damage to the work or machine

Engineering Contradiction:
ImproveproductivityVSAvoidimpact sound
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The contact operation is divided into two distinct phases: a first contact operation at a first speed and a second contact operation at a second speed. This segmentation allows each phase to be optimized for its specific purpose, resolving the contradiction between speed and accuracy

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact speed is made dynamic rather than static, with the system automatically switching between a first speed and a second speed based on the detection phase. This dynamic adjustment allows the system to achieve both high accuracy and high productivity

Inventive Principle:
Principle #15Dynamics

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

This approach allows for high detection accuracy while reducing detection time, enabling efficient processing with adjustable contact speeds to suit various workpiece shapes and machine configurations, improving productivity and accuracy.

Implementation Method 1

An increase in load of the motor can be detected by an increase in current value of the motor

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Implementation Method 2

when the tool machine is an NC tool machine, the contact between the detection jig and the work can be detected with higher accuracy by detecting an increase in position deviation which is a difference signal between a tool post position instruction given to the motor and a feedback signal returned from the motor

Methodology Applied
Scientific EffectFeedback: Feedback

Data Source

PatentEP3248731B1Work processing method, spindle angle correction device, and complex lathe
Publication Date: 2021.04.07 NAKAMURATOME SEIMITSU IND
  • EP3248731B1 patent drawingFigure 1
  • EP3248731B1 patent drawingFigure 2~4
  • EP3248731B1 patent drawingFigure 5

AI summary

[Object] In a technique of detecting a dimension or a posture of a work by bringing a rigid member (a detection jig) having a simple shape into contact with a work loaded into a tool machine and processing the work in accordance with a detection result, it is designed to more appropriately set a contact speed depending on a case where detection accuracy for a dimension or a posture of the work is important or productivity is important. [Solving Means] A first speed and a second speed slower than the first speed are set as a contact speed when a work w and a detection jig t attached to a tool post are brought into contact with each other to detect a position or a posture of the work w, the work and the detection jig are brought into contact with each other at the first speed, the detection jig and the work contacting each other are separated from each other by a predetermined distance, the work and the detection jig which are separated from each other are brought into contact with each other at the same position at the second speed, and a correction value δ is obtained based on a tool post position or a spindle angle during the second contact.