Additive Workpiece Support Control for Thermal Expansion Compensation

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Solution Overview

Problem

Conventional methods for addressing thermal expansion during additive manufacturing on complex-shaped workpieces are inefficient and time-consuming, particularly when calculating the amount of thermal expansion.

Innovation Solution

An additive manufacturing apparatus with a control unit that monitors and controls the position of a support unit based on torque feedback and position detection, adjusting the support unit's movement to maintain a predetermined target value, thereby compensating for thermal expansion and contraction of the workpiece.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If thermal expansion calculation is performed for complex-shaped workpieces, then thermal expansion compensation is achieved, but calculation time increases significantly

Engineering Contradiction:
Improvethermal expansion compensation accuracyVSAvoidcalculation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent implements feedback control by detecting the actual position of the support unit during additive manufacturing and comparing it with the target position. The control unit adjusts the support unit's position based on this feedback to compensate for thermal expansion, eliminating the need for complex predictive calculations while maintaining high precision

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the complex computational mechanism (thermal expansion calculation) with a physical detection and feedback mechanism. Instead of calculating thermal expansion based on temperature and material properties, the system directly detects position changes and compensates accordingly, simplifying the control process

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

2Manufacturing precision

If the support unit position is continuously adjusted during additive manufacturing, then thermal expansion is compensated, but control system complexity increases

Engineering Contradiction:
Improveworkpiece surface accuracyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The support unit automatically adjusts its own position based on feedback from the detection unit, without requiring complex external control calculations. The system serves itself by using the detected position information to directly control the support unit's movement, reducing overall system complexity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

A feedback loop is established where the detection unit monitors the support unit's position and feeds this information back to the control unit, which then makes simple positional adjustments. This feedback mechanism achieves precise control through simple iterative corrections rather than complex predictive control

Inventive Principle:
Principle #23Feedback

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

This approach enables high-precision additive manufacturing by preventing workpiece distortion and residual stress, without the need for complex thermal expansion calculations, ensuring high-quality manufacturing outcomes.

Implementation Method 1

When the workpiece is irradiated with a laser beam, the workpiece thermally expands

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a first detection unit configured to detect a physical quantity correlated with torque applied to the drive unit

Methodology Applied
Scientific EffectTorque detection: Torque

Data Source

PatentEP4729208A1Additive processing device, additive processing method, and additive processing program
Publication Date: 2026.04.22 DMG MORI CO LTD
  • EP4729208A1 patent drawingFigure 1
  • EP4729208A1 patent drawingFigure 2
  • EP4729208A1 patent drawingFigure 3

AI summary

Provided is a technology for addressing thermal expansion in a way that is different from conventional methods during additive manufacturing on a workpiece. An additive manufacturing apparatus includes a laser head configured to perform additive manufacturing on a workpiece, a first support unit configured to support one side of the workpiece in a direction along a predetermined axis and rotatably support the workpiece with respect to the predetermined axis, a second support unit configured to support the other side of the workpiece in the direction along the predetermined axis and rotatably support the workpiece with respect to the predetermined axis, a drive unit configured to move the second support unit along the direction along the predetermined axis, a first detection unit configured to detect a physical quantity correlated with torque applied to the drive unit, and a control unit. The control unit executes a process of controlling the drive unit during at least one of additive manufacturing on the workpiece and cooling of the workpiece such that the physical quantity detected by the first detection unit approaches a predetermined target value.