CNC Axis Homing With Non-Contact Switching Sensors

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Solution Overview

Problem

Existing CNC machine axis positioning systems using mechanical sensors suffer from high position errors, complex structures, long operation times, and susceptibility to wear, dirt, and environmental stresses, leading to accuracy and repeatability issues.

Innovation Solution

An apparatus employing inductive or capacitive switching sensors with a switching bar and sensor housing that defines a switching point for axis positioning, providing high accuracy and repeatability while protecting against electromagnetic noise, vibrations, and environmental factors, and reducing workspace encumbrance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If mechanical sensors are used for axis positioning, then the structure is simple, but the position error is high and accuracy is poor

Engineering Contradiction:
Improvesensor structureVSAvoidposition error
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical contact sensors with inductive or capacitive proximity sensors that detect the switching point without physical contact. This substitution eliminates mechanical wear and positioning errors while maintaining structural simplicity, directly resolving the contradiction between simple structure and high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If mechanical sensors are used for axis positioning, then the structure is simple, but the sensor deteriorates rapidly due to wear and environmental factors

Engineering Contradiction:
Improvesensor structureVSAvoidsensor durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces mechanical contact sensors with inductive or capacitive proximity sensors that detect the switching point without physical contact. This substitution eliminates mechanical wear and positioning errors while maintaining structural simplicity, directly resolving the contradiction between simple structure and high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If mechanical sensors are used for axis positioning, then the structure is simple, but the operation time is long and accuracy is not significant

Engineering Contradiction:
Improvesensor structureVSAvoidpositioning time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent replaces mechanical contact sensors with inductive or capacitive proximity sensors that detect the switching point without physical contact. This substitution eliminates mechanical wear and positioning errors while maintaining structural simplicity, directly resolving the contradiction between simple structure and high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If mechanical sensors are exposed to machining environment, then the structure is simple, but the sensor is exposed to wear and dirt

Engineering Contradiction:
Improvesensor protectionVSAvoidsensor exposure to dirt and wear
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical contact sensors with inductive or capacitive proximity sensors that detect the switching point without physical contact. This substitution eliminates mechanical wear and positioning errors while maintaining structural simplicity, directly resolving the contradiction between simple structure and high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

5Device complexity

If mechanical sensors are used for axis positioning, then the structure is simple, but the positioning accuracy and repeatability are not significant

Engineering Contradiction:
Improvesensor structureVSAvoidpositioning accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical contact sensors with inductive or capacitive proximity sensors that detect the switching point without physical contact. This substitution eliminates mechanical wear and positioning errors while maintaining structural simplicity, directly resolving the contradiction between simple structure and high measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

The solution achieves high accuracy and repeatability in CNC machine axis positioning with reduced timing, enhanced sensor protection, and simplified maintenance, while minimizing the need for mechanical sensors and reducing workspace clutter.

Implementation Method 1

at least one switching sensor (12, 21, 22), either of inductive or capacitive type

Methodology Applied
Scientific EffectInductive sensing: Electromagnetic Induction

Implementation Method 2

at least one switching sensor (12, 21, 22), either of inductive or capacitive type

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP3250971B1Apparatus and procedure for homing and subsequent positioning of axes of a numerical control machine
Publication Date: 2022.03.30 ZERAS SRL
  • EP3250971B1 patent drawingFigure 1~2a
  • EP3250971B1 patent drawingFigure 2b~3
  • EP3250971B1 patent drawingFigure 4a~4b

AI summary

Apparatus for the homing and subsequent positioning of the axes of a numerical control machine, comprising: - motion actuators means (13), operatively connected to motor means for moving a machine worktable of said apparatus; - a control unit (14), - an input/output unit (15), operatively connected to said control unit (14) for the definition of at least one working axis, where said apparatus comprises at least one switching sensor (12), either of inductive or capacitive type, at least one switching bar (10) for the definition of at least one switching point (11) identified on said at least one worktable by means of said at least one switching sensor (12), said switching sensors (12) and switching points (11) being fixed or mobile, said at least one switching bar (10) comprising a detection area for said at least one switching sensor (12), said area being shared into a first (18), respectively a second (17) detection section, and a plurality of protection and fastening areas (16), and a sensor housing (20) for the insertion, protection and sliding of one or more switching sensors.