Gas Laser Power Stabilization for 3D Printing

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Solution Overview

Problem

Gas lasers, such as CO2-lasers, experience significant deviations in power over short and long periods due to changing operational conditions, making it difficult to maintain stable laser power for long periods in rapid prototyping methods like laser sintering, which affects the quality of manufactured three-dimensional objects.

Innovation Solution

A method where the laser power is measured within a time window of power change, and an input control signal is adjusted using a switch-on ramp to compensate for deviations, employing a sensor with a response delay of 10 μs or less to stabilize the power, ensuring accurate power control during layer-by-layer solidification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a gas laser is used for rapid prototyping, then the ability to solidify building material layer by layer is achieved, but the laser power deviates significantly over short and long periods affecting manufacturing quality

Engineering Contradiction:

Improvelaser powerVSAvoidpower stability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent implements a feedback control system where a sensor continuously measures the actual laser power and feeds this information back to a control unit. The control unit compares the measured power with the desired power level and automatically adjusts the laser input signal to eliminate deviations, thereby maintaining stable laser power over time despite changing operational conditions

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces manual or simple mechanical power adjustment mechanisms with an automated electronic control system. The control unit uses electronic signals to dynamically adjust the laser power based on real-time sensor feedback, substituting complex mechanical adjustment systems with a more precise and responsive electronic control approach

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If laser power is continuously adjusted to maintain stability, then power consistency improves, but the complexity of the control system increases

Engineering Contradiction:

Improvepower stabilityVSAvoidcontrol system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control system is designed to be self-regulating, automatically detecting power deviations through the sensor and correcting them without external intervention. The system monitors its own performance and makes autonomous adjustments to maintain stable laser power, reducing the need for complex external control mechanisms

Inventive Principle:

Principle #25Self-service

3Manufacturing precision

If the laser power is measured and controlled in real-time, then manufacturing precision improves, but the response time and system complexity increase

Engineering Contradiction:

Improvesolidification precisionVSAvoidpower measurement and control time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The control system performs preliminary measurements of laser power at strategically chosen time points, such as at the beginning of each track or layer, to predict and prevent power deviations before they affect manufacturing precision. This proactive approach allows the system to make corrective adjustments in advance, maintaining precision without requiring continuous real-time measurement

Inventive Principle:

Principle #10Preliminary action

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 allows for automatic adjustment of the laser input signal to compensate for power deviations as short as 10 μs, preventing switch-on overshoots and ensuring consistent power delivery, thereby improving the quality of the manufactured objects by stabilizing the laser power over time.

Implementation Method 1

a sensor is used as a means for measuring the power, which has a response delay of about 10 μs or less

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

the object is solidified layer by layer by solidifying a building material by means of a beam of a gas laser

Methodology Applied

Scientific EffectLaser heating: Laser

Implementation Method 3

solidifying a building material by means of a beam of a gas laser

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS8303886B2Method of manufacturing a three-dimensional object

Publication Date: 2012.11.06 EOS GMBH ELECTRO OPTICAL SYST

AI summary

A method of manufacturing a three-dimensional object is disclosed, in which the object is solidified layer by layer by solidifying a building material by means of a beam of a gas laser at locations in each layer corresponding to the cross section of the object, wherein the power of the laser is measured and the power of the laser is controlled according to the measured value. The power measurement takes place in a time window, in which a change of the power occurs, and an input control signal of the laser is controlled according to the measured values.