Lathe Tool Post Height Deviation Correction

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Solution Overview

Problem

Existing lathe technologies face challenges in accurately setting the relative cutting edge height of a tool to a workpiece, leading to incomplete cutting ends and increased machining steps, especially when dealing with small diameters where deviations significantly impact precision.

Innovation Solution

A lathe system with a control unit that performs multiple cutting steps, measures diameters before and after each step, calculates deviations, and adjusts the tool's position to ensure accurate alignment of the cutting edge height with the workpiece's center line, using a tool post drive unit and input unit for precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If positioning means (ball screw, slide, motor, NC unit, encoder, linear scale) is used to adjust cutting edge height, then cutting edge height can be efficiently adjusted to match the work, but cutting edge may deviate from the set height during machining

Engineering Contradiction:
Improvecutting edge height positioning accuracyVSAvoidcutting edge height stability during machining
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system performs preliminary cutting to create a reference surface on the workpiece before final positioning. This reference surface is used to detect and correct cutting edge height deviations, ensuring accurate positioning before actual machining begins

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses a detector to measure the position of the cutting edge relative to the workpiece center line in real-time. Based on the detected deviation, the control unit automatically adjusts the tool post position to correct the cutting edge height, forming a closed-loop feedback control system that maintains positioning accuracy throughout machining

Inventive Principle:
Principle #23Feedback

2Device complexity

If cutting edge height is not accurately adjusted, then machining can proceed without complex adjustment mechanisms, but incomplete cutting ends occur and number of machining steps increases

Engineering Contradiction:
Improveadjustment mechanism complexityVSAvoidnumber of machining steps
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The system automatically detects cutting edge height deviations and performs self-correction by adjusting the tool post position through the ball screw mechanism. This self-service capability eliminates the need for manual intervention and additional machining steps to correct positioning errors

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system performs preliminary cutting to create a reference surface and detects cutting edge height deviation before final machining. This preliminary detection and correction phase prevents incomplete cutting ends and eliminates the need for additional corrective machining steps

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2070615B1Lathe, computer program for controlling lathe, and machining method in lathe
Publication Date: 2014.03.05 TSUGAMI CORP
  • EP2070615B1 patent drawingFigure 1
  • EP2070615B1 patent drawingFigure 2
  • EP2070615B1 patent drawingFigure 3

AI summary

With the use of a tool (41), first cutting is applied to a work (W), and then second cutting is applied to the work (W) while the tool (41) is transferred in an X-axis direction. Then, an amount of deviation dy between the cutting edge height of the tool (41) and the center line of the work (W) is calculated based on a first diameter value (D1) and second diameter value (D2) measured after the first cutting and second cutting are applied, and the travel distance of the tool (41) between the first cutting and the second cutting. Machining to the work (W) is resumed after the amount of deviation is corrected.