Induction Heating Power Control in Additive Manufacturing

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Solution Overview

Problem

Induction heating systems in additive manufacturing lack precise control over heating power due to unknown actual heating capacity, leading to inefficient temperature regulation and conservative operating parameters.

Innovation Solution

A method to determine and regulate the actual heating power in a component by calculating and subtracting power losses from the electrical power input, allowing for real-time adjustments to match target heating values, using coolant flow rates, temperature sensors, and accounting for waste heat emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the electrical power output of the induction generator is increased to improve heating efficiency, then the heating power increases, but the inductance and ohmic resistance of the heating system change due to position and component variations, causing the actual heating power to deviate from the target value

Engineering Contradiction:
Improveheating powerVSAvoidheating power control accuracy
Core Design Contradiction:
PowerVSMeasurement precision

Solution Approach 1:

The patent implements a feedback control mechanism where the actual heating power is continuously determined by measuring electrical parameters (electrical power, coolant flow rate, temperature difference) and calculating the heating power after subtracting power losses. This actual heating power is then compared with the target heating power, and the electrical power output of the induction generator is adjusted accordingly to minimize the deviation, thereby maintaining accurate heating control despite variations in inductance and resistance.

Inventive Principle:
Principle #23Feedback

2Area of stationary object

If the induction coil is mechanically displaced to different positions to heat different areas of the component, then the heating coverage improves, but the electrical properties (inductance and ohmic resistance) change with position, reducing the maximum possible power and heating efficiency

Engineering Contradiction:
Improveheating coverage areaVSAvoidmaximum heating power
Core Design Contradiction:
Area of stationary objectVSPower

Solution Approach 1:

The patent applies dynamics by making the electrical power output of the induction generator dynamically adjustable based on the coil position. As the induction coil is mechanically displaced to different positions, the control system continuously determines the actual heating power and adjusts the electrical power output in real-time to compensate for changes in inductance and ohmic resistance. This ensures that the heating power remains optimized across the entire heating coverage area, rather than being limited by the maximum power at a single fixed position.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the temperature control is operated with conservative parameters to account for unknown heating rates, then the temperature stability improves, but the productivity and heating efficiency decrease

Engineering Contradiction:
Improvetemperature stabilityVSAvoidheating efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The patent replaces conservative temperature control with an active feedback control system. Instead of using fixed conservative parameters, the system continuously determines the actual heating power by measuring electrical parameters and coolant temperature differences, compares it with the target heating power, and adjusts the electrical power output in real-time. This feedback mechanism maintains temperature stability while allowing the system to operate at optimal power levels, thereby eliminating the productivity loss associated with conservative control parameters.

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

Enables precise and dynamic control of heating power, improving the efficiency and accuracy of the induction heating process without disrupting the additive manufacturing process, allowing for rapid determination and storage of position-dependent data for improved reactive and predictive control.

Implementation Method 1

an induction heating system (100, 200), in particular an induction generator (11) and an induction coil (40)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The supply lines are cooled using a coolant

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The heat output, which is given off as waste heat to the cooling liquid of the supply lines

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3984332B1Control of an induction heating system in generative production processes
Publication Date: 2023.07.05 SIEMENS ENERGY GLOBAL GMBH & CO KG
  • EP3984332B1 patent drawingFigure 1~2

AI summary

The invention relates to a method which controls a heating power induced in a component 1 in a generative manufacturing process. The heating power is induced by an induction heating system. The closed-loop control method according to the invention is based on the concept of indirectly determining the previously unknown heating power which is actually induced in component 1. This is accomplished by the power losses, which substantially consist of waste heat to the cooling liquid and to the other surroundings, being deducted from the electrical power that is inserted into the induction heating system (specifically, the electrical power of the induction generator 11). The power losses are calculated, insofar as is possible; alternatively, they can also be estimated.