Method and device to ascertain a quality of a product obtained by subtractive manufacturing

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Solution Overview

Problem

Existing subtractive manufacturing methods struggle with inefficiencies and inaccuracies in determining the quality of the final product, often requiring additional machining processes that increase costs and time.

Innovation Solution

A method and device that automatically measure and correct machining forces in real-time using a sensor system to ensure dimensional accuracy, involving the measurement of three components of machining force and applying corrections based on deflection/test force relations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If additional machining processes such as grinding and honing are performed to fulfill quality properties, then manufacturing precision is improved, but productivity decreases and manufacturing cost increases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies preliminary action by determining deflection/test force relations before actual machining operations. The system pre-calibrates the relationship between machining forces and device deflections, allowing real-time compensation during machining without requiring additional post-processing steps. This preliminary calibration enables the machining process to achieve required precision directly, eliminating the need for subsequent grinding or honing operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by continuously monitoring machining forces during the subtractive manufacturing process and automatically adjusting device parameters based on measured deflections. The system uses the predetermined deflection/test force relations to calculate actual deflections from measured forces and applies real-time corrections to maintain dimensional accuracy. This closed-loop feedback control ensures quality properties are met during the primary machining operation itself, avoiding the need for additional corrective machining processes.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If additional machining processes such as grinding and honing are performed to fulfill quality properties, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidnumber of machining processes
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies universality by creating a multi-functional system that combines force measurement, deflection calculation, and automatic compensation capabilities within the existing subtractive manufacturing device. The control unit serves multiple functions: it determines deflection/test force relations during calibration, monitors machining forces during operation, calculates actual deflections using predetermined relations, and applies corrections automatically. This integrated approach eliminates the need for separate grinding and honing equipment, reducing overall device complexity while maintaining high manufacturing precision.

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

3Productivity

If machining forces are not corrected, then productivity is maintained, but manufacturing precision deteriorates due to device deflection

Engineering Contradiction:
Improvemachining efficiencyVSAvoiddimensional accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies mechanics substitution by replacing physical mechanical compensation methods with a computational approach. Instead of using complex mechanical adjustment mechanisms or multiple machining passes to correct deflection errors, the system uses software-based calculations. The control unit automatically computes actual deflections from measured machining forces using predetermined deflection/test force relations and applies digital corrections to drive control signals. This computational method maintains high productivity while achieving superior manufacturing precision compared to traditional mechanical correction approaches.

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

Data Source

PatentEP3933524B1Method and device to ascertain a quality of a product obtained by subtractive manufacturing
Publication Date: 2025.11.26 KISTLER HLDG AG
  • EP3933524B1 patent drawingFigure 1~2
  • EP3933524B1 patent drawingFigure 3~4
  • EP3933524B1 patent drawingFigure 5~6

AI summary

The invention relates to a method to ascertain a quality of a product (21) obtained by subtractive manufacturing with a device (1) from a workpiece (20), said method comprises: in a first step (I): determining at least one deflection/test force relation (DFX, DFY, DFZ) for a deflection (D15) of said device (1); in a second step (II): measuring an actually exerted machining force (AMF); automatically determining a machining force reference (MFR) for said actually exerted machining force (AMF); automatically evaluating, whether said actually exerted machining force (AMF) deviates from said machining force reference (MFR); if an actually exerted machining force (AMF) deviates from said machining force reference (MFR), then said deflection/test force relation (DFX, DFY, DFZ) is used to automatically determine for said actually exerted machining force (AMF) at least one correction deflection (CDX, CDY, CDZ) of said device (1); and automatically creating at least one corrected drive control signal (CDS, CDS') to fully or partially reduce said correction deflection (CDX, CDY, CDZ).