Spherical Cap Feeler for 5-Axis Machining Tolerances

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Solution Overview

Problem

5-axis machining units struggle to achieve high-quality surface finishes on three-dimensionally shaped workpieces with manufacturing tolerances or dimensional deviations, particularly when processing concave or convex surfaces, as existing tracing units require axis-oriented alignment and cannot accommodate tolerances, leading to insufficient product quality and limited usability on cardanic 5-axis heads.

Innovation Solution

A machining unit with a tool head and feeler arrangement featuring a spherical cap contact surface that allows the tool head to maintain a defined distance from the workpiece, enabling precise machining of concave and convex surfaces by compensating for tolerances and allowing use on both Cartesian and cardanic 5-axis heads, with a scanning arrangement that eliminates the need for axis-oriented alignment and includes features like a spring-loaded mounting, sensors, and compressed air for improved accuracy and control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a tracing unit with tracing curves is used, then the probing curve can be aligned parallel to the edge of the workpiece, but it cannot be used on cardanic 5-axis heads and requires axis-oriented alignment

Engineering Contradiction:
Improvealignment requirementVSAvoidcompatibility with 5-axis head types
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The feeler element is designed with a spherical contact surface that can adapt to various workpiece geometries including concave and convex surfaces. The spherical shape allows the feeler element to maintain contact with the workpiece surface regardless of the specific curvature, enabling universal application on both Cartesian and cardanic 5-axis heads without requiring axis-oriented alignment.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The feeler arrangement with its spherical feeler element is designed to be universally compatible with different types of 5-axis machining heads. The spherical contact surface can adapt to various workpiece geometries and machine configurations, making the same feeler arrangement applicable to both Cartesian and cardanic 5-axis heads, thereby eliminating the limitation of axis-oriented alignment requirements.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Manufacturing precision

If conventional milling is performed without compensating for tolerances, then the milling process is simple, but the desired surface quality and dimensional accuracy are not achieved

Engineering Contradiction:
Improvesurface qualityVSAvoidprocessing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Before the actual milling operation, the feeler element scans the workpiece surface to detect tolerances and dimensional deviations. This preliminary measurement action allows the system to compensate for variations in the workpiece geometry during subsequent milling operations, ensuring high surface quality and dimensional accuracy without requiring complex real-time adjustments during machining.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The feeler arrangement provides feedback information about the actual workpiece surface geometry, including tolerances and deviations. This feedback is used to adjust the milling process parameters and tool paths, enabling the system to compensate for workpiece variations and achieve the desired surface quality and dimensional accuracy while maintaining relatively simple processing procedures.

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If the feeler element has a flat contact surface, then the structure is simple, but it cannot properly scan concave and convex workpiece surfaces

Engineering Contradiction:
Improvefeeler element structureVSAvoidscanning capability
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The feeler element employs a spherical contact surface instead of a flat one. This curved geometry allows the feeler element to properly follow and scan concave and convex workpiece surfaces, maintaining continuous contact and accurate measurement capability across varying surface geometries while keeping the overall structure relatively simple.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 enables high-precision machining of workpieces with concave or convex shapes and tolerances, ensuring good surface quality and dimensional accuracy at reduced costs, while minimizing rejects and energy consumption, and allowing for flexible use on different types of 5-axis machining heads.

Implementation Method 1

the probe element is preferably guided in a sliding manner with its contact surface over the workpiece and is supported in a sliding manner on the workpiece

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the contact surface of the feeler element for supporting the machining unit on the workpiece is at least partially in the form of a spherical cap

Methodology Applied
Scientific EffectPressure distribution: Pressure Increase

Data Source

PatentEP2368664B1Processing machine
Publication Date: 2014.06.18 HOMAG HOLZBEARBEITUNGSSYST
  • EP2368664B1 patent drawingFigure 1
  • EP2368664B1 patent drawingFigure 2

AI summary

The present invention provides a machining unit, in particular a 5-axis machining unit, for machining preferably three-dimensionally shaped workpieces, which preferably consist at least partially of wood, plastic or the like, comprising: a tool head for arranging at least one cutting edge, and a sensing arrangement, which has a sensing element with a contact surface for supporting the machining unit when used on a workpiece, wherein the contact surface has at least partially the shape of a spherical cap.