Adaptive Gear Hard Machining for Heat-Treated Tooth Distortion

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Solution Overview

Problem

Hardening distortion in gear workpieces after heat treatment poses challenges in hard machining, leading to potential tool collisions and grinding burns, and existing methods require precise pre-measurement to account for these distortions, which can be inefficient and prone to errors.

Innovation Solution

A method using NC-controlled gear processing machines with sensors to provide real-time measurement and movement data for adaptive relative movements, allowing for workpiece-specific adjustments during hard machining to account for distortions, thereby avoiding collisions and optimizing machining sequences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If precise 3D measurement is performed after heat treatment to determine hardening distortion, then manufacturing precision is improved, but loss of time increases due to additional measurement steps

Engineering Contradiction:
Improvehardening distortion compensationVSAvoidmeasurement time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent combines the measurement function and machining function into a single integrated system. The sensor integrated into the machining tool performs measurement during the machining process itself, eliminating the need for separate pre-measurement steps and enabling real-time adaptation of machining parameters based on actual workpiece geometry

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces traditional mechanical 3D measurement systems with an optical sensor system integrated into the machining tool. This substitution enables continuous real-time measurement during machining without the time loss associated with separate measurement operations

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

2Reliability

If tool movements are carefully controlled to avoid collisions with tooth surfaces, then reliability is improved, but productivity decreases due to reduced machining efficiency

Engineering Contradiction:
Improvetool collision avoidanceVSAvoidmachining efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements a feedback loop where the sensor continuously monitors the actual workpiece geometry during machining, and this information is fed back to the control system which automatically adjusts machining parameters in real-time. This enables aggressive machining parameters to be used safely while maintaining collision avoidance

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transforms the static, pre-programmed toolpath into a dynamic, adaptive process. The machining parameters including toolpath, feed rate, and depth of cut are continuously adjusted based on real-time sensor feedback, allowing the system to optimize productivity while maintaining reliability

Inventive Principle:
Principle #15Dynamics

3Object-generated harmful factors

If material removal is limited to avoid grinding burns, then object-generated harmful factors are reduced, but productivity decreases due to excessive material removal restrictions

Engineering Contradiction:
Improvegrinding burnsVSAvoidmaterial removal rate
Core Design Contradiction:
Object-generated harmful factorsVSProductivity

Solution Approach 1:

The sensor provides real-time feedback on the actual workpiece geometry and machining conditions, enabling the control system to precisely control material removal rates. This allows maximum material removal without causing grinding burns, as the system can detect and respond to changing conditions instantaneously

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent dynamically changes machining parameters including feed rate, depth of cut, and spindle speed based on real-time sensor feedback. This enables optimization of material removal rate while preventing grinding burns by adjusting parameters according to actual workpiece conditions

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3584026B1Method for hard machining of a roughly cut and heat-treated toothed wheel work piece
Publication Date: 2025.01.01 KLINGELNBERG GMBH
  • EP3584026B1 patent drawingFigure 1
  • EP3584026B1 patent drawingFigure 2A
  • EP3584026B1 patent drawingFigure 2B

AI summary

A method (100) for hard machining (107) a pre-cut and heat-treated gear workpiece (W) with a tool in a gear machining machine comprising sensors and/or encoders, comprising the following steps: - providing (102) target data (SD) of the gear workpiece (W), - determining a first relative movement (103) of the tool relative to the gear workpiece (W) based on the target data (SD), - executing the first relative movement (103), wherein an NC control brings the tool into controlled contact with the gear workpiece (W) by executing the first relative movement (103), - providing (104) real-time measured values ​​(MW) and motion data (BD) by means of the sensors and/or encoders during the execution of the first relative movement (103), - performing an evaluation (105) of the real-time measured values ​​(MW) together with the motion data (BD) and determining adapted, workpiece-specific relative movements,- Hard machining (107) of at least one area of ​​a tooth of the gear workpiece (W), wherein the NC control performs the adapted, workpiece-specific relative movements of the tool relative to the gear workpiece (W).