Numerical Controller Radius Compensation Interference Detection

Solution Overview

Problem

Existing numerical controllers fail to detect abnormal interference between a tool and a workpiece, particularly when the tool's blade portion interferes with the workpiece during machining, as they exclude the blade portion from interference checks and cannot account for positional relationships and peripheral speeds.

Innovation Solution

A numerical controller with a contactable direction setting unit, compensation direction analysis unit, and interference check unit that determines abnormal interference by analyzing machining programs and tool postures to identify if the compensation direction of radius compensation is within the contactable directions, allowing for accurate detection of interference between a tool and a workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the blade portion is excluded from interference check, then false abnormal detection is avoided during normal machining, but abnormal interference cannot be detected when it actually occurs

Engineering Contradiction:

Improveaccuracy of interference detectionVSAvoidcomplexity of interference check system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by differentiating the treatment of different parts of the blade portion. Instead of uniformly excluding the entire blade portion from interference checks, the system specifically targets the tip region (within a predetermined distance from the tip) for interference detection while allowing other parts to be excluded. This localized approach enables detection of abnormal interference at the critical tip area without triggering false alarms during normal machining operations where other parts of the blade may contact the workpiece.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the blade portion into multiple regions: a tip region within a predetermined distance from the tip that is subject to interference checks, and other regions that are excluded from checks. This segmentation allows the system to focus detection resources on the most critical area (the tip) where abnormal interference is most likely to occur and cause damage, while avoiding false detections from contacts in non-critical areas.

Inventive Principle:

Principle #1Segmentation

2Reliability

If interference check includes all parts of the tool, then all potential interference is detected, but false abnormal detection occurs during normal machining operations

Engineering Contradiction:

Improvecompleteness of interference detectionVSAvoidaccuracy of abnormal interference identification

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by differentiating the treatment of different parts of the blade portion. Instead of uniformly excluding the entire blade portion from interference checks, the system specifically targets the tip region (within a predetermined distance from the tip) for interference detection while allowing other parts to be excluded. This localized approach enables detection of abnormal interference at the critical tip area without triggering false alarms during normal machining operations where other parts of the blade may contact the workpiece.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If radius compensation is applied to the blade portion center position, then tool positioning accuracy is improved, but abnormal interference at the rotation center cannot be detected

Engineering Contradiction:

Improvetool positioning accuracyVSAvoiddetection of abnormal interference at rotation center

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies preliminary action by performing interference checks on the tip region of the blade portion before the actual machining operation executes. By checking whether the tip region interferes with the workpiece in advance, the system can detect abnormal conditions (such as the tool rotating center contacting the workpiece) before they cause damage. The predetermined distance threshold is set to include the rotation center area, enabling detection of abnormal interference that would occur during radius compensation operations.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10088831B2Numerical controller capable of checking interference between tool and workpiece

Publication Date: 2018.10.02 FANUC LTD

AI summary

The numerical controller detects an abnormal interference between targets for interference check in a machine tool, including a tool and a workpiece, based on a machining program. The numerical controller changes a direction (contactable direction) in which the tool can contact the workpiece for machining and determines that an interference between the tool and the workpiece is abnormal if the tool compensation direction of radius compensation is not included in the changed contactable direction for the tool.