NC Tool Post Pivot Limits for Machine Element Interference Avoidance

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Solution Overview

Problem

Current machine tools face challenges in efficiently avoiding interference between the tool unit and other machine elements during machining, particularly when the tool unit is pivotably attached to a turret tool post, leading to restricted pivoting ranges and increased costs due to costly 3D interference checking.

Innovation Solution

A machine tool system that includes operation control means to calculate a maximum pivoting angle and determine a no-entry region for the tool unit, preventing interference with other machine elements by inhibiting entry into a no-entry region, without relying on costly interference checking, using a limit value setting command within the numerical control program.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pivotable range of the tool unit is limited to avoid interference with the guide bush, then interference is avoided, but the machining flexibility and pivoting range are reduced

Engineering Contradiction:
Improveinterference avoidanceVSAvoidmachining flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the pivoting angle limit dynamic rather than fixed. The control unit calculates the maximum pivoting angle in real-time based on the current position of the tool post and the specific machining operation being performed. This allows the tool unit to pivot within a larger range when the tool post is positioned away from the guide bush, while automatically restricting the pivoting angle when the tool post is close to the guide bush to prevent interference. This dynamic adjustment resolves the contradiction between maintaining reliable interference avoidance and preserving machining flexibility.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If a 3D interference checking function is provided to the NC apparatus, then interference checking accuracy is improved, but the cost of the machine tool increases

Engineering Contradiction:
Improveinterference checking accuracyVSAvoidmachine tool cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the essential interference checking functionality from a complex 3D interference checking system and implements a simplified calculation-based approach. Instead of using expensive 3D models and comprehensive interference checking software, the control unit calculates the maximum pivoting angle using basic geometric relationships between the tool post position, guide bush location, and tool unit dimensions. This extracted essential function achieves sufficient interference checking accuracy for the specific application while dramatically reducing system complexity and cost.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If the tool unit is allowed to pivot to extreme angles, then machining capability is improved, but interference with the guide bush occurs

Engineering Contradiction:
Improvemachining capabilityVSAvoidinterference with guide bush
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback by continuously monitoring the position of the tool post and using this information to dynamically adjust the maximum pivoting angle of the tool unit. The control unit receives position feedback from the tool post, calculates the appropriate pivoting angle limit based on this feedback and the current machining operation, and applies this limit to prevent the tool unit from pivoting into positions that would cause interference with the guide bush. This feedback mechanism enables the system to achieve extreme pivoting angles when safe while automatically preventing interference when the tool post position creates a risk.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2937752B1Machine tool and interpretive program
Publication Date: 2021.06.16 STAR MICRONICS CO LTD
  • EP2937752B1 patent drawingFigure 1
  • EP2937752B1 patent drawingFigure 2
  • EP2937752B1 patent drawingFigure 3

AI summary

A machine tool includes a tool post having a tool unit for machining a workpiece, operation control means for controlling the operation of the tool unit in accordance with a plurality of commands described in a numerical control program and movement limiting means for inhibiting entry of the tool unit into a no-entry region. The plurality of commands include a limit value setting command for calculating a limit value of a position of the tool unit avoiding interference with a machine element located within a movable region of the tool unit and for determining the no-entry region by the calculated limit value. Upon reading the limit value setting command out of the numerical control program, the operation control means calculates the limit value and determines the no-entry region by the calculated limit value.