Automatic Lathe Control for Eccentric Hole Machining

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Solution Overview

Problem

The existing turning process for eccentric positions on lathes requires complex NC programming to calculate tool positions point-by-point, making it difficult to process eccentric shapes or portions efficiently.

Innovation Solution

A machine tool system that includes a main spindle, a tool, a feeder, an input receiver, and a controller to set a virtual circle with an offset center from the shaft center, allowing the tool to move along the circumference of this circle synchronized with the workpiece rotation, enabling simple processing of eccentric portions by inputting the eccentric distance and radius.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If complex NC programming is used to calculate tool positions point by point, then machining precision of eccentric portions can be achieved, but programming complexity and processing time increase significantly

Engineering Contradiction:
Improvemachining precisionVSAvoidprogramming complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual circle model that copies the essential geometric parameters (radius R and eccentricity e) of the target eccentric shape. Instead of calculating actual tool positions point by point, the system uses this simplified virtual model to generate machining commands, dramatically reducing programming complexity while maintaining machining precision through the preserved geometric relationships.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent transforms the complex point-by-point coordinate calculation into a parameter-based control system. By defining the eccentric shape through fundamental parameters (circle radius R and eccentricity e), the system changes the control approach from calculating numerous individual coordinates to simply managing these key parameters, thereby reducing programming complexity while maintaining precision.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If complex NC programming with point-by-point calculation is used, then accurate eccentric portions can be machined, but processing time increases

Engineering Contradiction:
Improvemachining precisionVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The virtual circle model copies only the essential geometric characteristics (radius and eccentricity) rather than storing or calculating all intermediate tool positions. This simplification dramatically reduces the computational workload and programming time required to generate machining paths, while the preserved geometric parameters ensure machining precision is maintained.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system performs preliminary setup by defining the virtual circle with parameters R and e before actual machining begins. This preliminary parameter definition eliminates the need for complex real-time calculations during machining, reducing overall processing time while ensuring precision through pre-established geometric relationships.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If simple settings are used for eccentric machining, then programming becomes easier, but achieving accurate eccentric shapes becomes difficult

Engineering Contradiction:
Improveprogramming easeVSAvoideccentric shape accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The virtual circle model copies the fundamental geometric parameters (radius R and eccentricity e) that define the eccentric shape. This copying approach allows simple parameter input while maintaining accurate shape representation, bridging the gap between ease of operation and machining precision by preserving essential geometric relationships in the virtual model.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent changes the control parameters from complex point-by-point coordinates to simple fundamental parameters (R and e). This parameter transformation makes programming easier while ensuring accurate eccentric shape generation, as the geometric relationships are maintained through these simplified parameters rather than lost in approximation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3363567B1Machine tool and method for machining using machine tool
Publication Date: 2022.08.31 CITIZEN WATCH CO LTD
  • EP3363567B1 patent drawingFigure 1~2
  • EP3363567B1 patent drawingFigure 3A~3B
  • EP3363567B1 patent drawingFigure 3C~3E

AI summary

To process an eccentric portion by using a machine tool and a method for processing by the machine tool with simple settings. An automatic lathe (1) (an example of the machine tool) includes a main spindle (2) that rotates a workpiece (50) about a shaft center (C1), a cutting tool (6) (an example of a tool) that processes the workpiece (50), a feeder (4) that moves the cutting tool (6), an input receiver (8) that receives inputs regarding an eccentric distance (D) and a radius (R), and a controller (7) that controls the movement by the feeder (4) such as to set a virtual circle (VI) having a radius of the distance (D) the input receiver receives, to set an offset virtual circle (V2) having a center at a position where a center of the virtual circle (VI) is offset from the shaft center (C1) of the workpiece (50) in the radial direction of the workpiece (50) by the radius (R) the input receiver (8) receives, and to move the cutting tool (6) along a circumference of the offset virtual circle (V2) in relation to a rotation of the workpiece (50) by the main spindle (2). A hole (60) (an example of an eccentric portion) is processed, which has the radius (R) at a position away from the shaft center (C1) by the distance (D).