Layer-Wise Defect Detection and Correction in Powder Bed 3D Printing

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Solution Overview

Problem

Additive manufacturing processes, such as laser powder bed fusion, face challenges in detecting and correcting defects in real-time, leading to waste and increased costs due to internal defects and machine calibration issues, where current systems only monitor after the build is complete and rely on operator notice for recalibration.

Innovation Solution

A method and system that incorporates a defect analysis subsystem to monitor each layer during the additive manufacturing process, detect defects, determine if correction is needed, identify correction parameters, and send commands to the device to perform corrections before proceeding to the next layer, utilizing thermal imaging and machining elements for defect repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If real-time defect detection and correction is implemented during additive manufacturing, then product quality and productivity are improved, but device complexity increases

Engineering Contradiction:
Improvedefect detection accuracyVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The defect analysis subsystem is nested within the additive manufacturing system, with the monitoring device integrated into the build chamber and the correction command system embedded in the control architecture. This nested structure allows real-time defect detection and correction without requiring entirely separate external systems, thereby improving manufacturing precision while limiting the increase in overall device complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The system implements continuous feedback loops where the monitoring device detects defects in real-time, the defect analysis subsystem analyzes the defect characteristics, and correction commands are automatically sent back to the additive manufacturing device to adjust process parameters. This closed-loop feedback mechanism enables real-time quality control and automatic correction, significantly improving manufacturing precision through dynamic parameter adjustment based on actual build conditions.

Inventive Principle:
Principle #23Feedback

2Reliability

If continuous monitoring of each layer is performed, then defect detection capability is improved, but loss of time increases

Engineering Contradiction:
Improvedefect detection capabilityVSAvoidbuild time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The monitoring device operates continuously throughout the additive manufacturing process, capturing images or data from each layer as it is built without interrupting the build flow. This continuous monitoring approach ensures that defects are detected in real-time while maintaining the continuity of the manufacturing process, thereby improving reliability without proportionally increasing the total build time through interruptions.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system prioritizes critical defect detection by analyzing each layer quickly and making rapid correction decisions. For minor defects that do not require immediate correction, the system can skip detailed analysis or defer correction to later stages, allowing the build process to progress efficiently while still maintaining high reliability for critical quality issues.

Inventive Principle:
Principle #21Skipping (Rushing through)

3Productivity

If automatic correction commands are sent during the build process, then productivity is improved by reducing scrap, but device complexity increases

Engineering Contradiction:
ImproveproductivityVSAvoidcontrol system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The additive manufacturing system performs self-correction by automatically receiving and executing correction commands generated by the defect analysis subsystem. When defects are detected, the system autonomously adjusts its own process parameters without requiring external human intervention or complex external control systems, thereby improving productivity by reducing scrap while limiting the increase in device complexity through self-managed correction capabilities.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The correction mechanism works by dynamically changing process parameters such as laser power, scan speed, or layer thickness based on detected defects. This parameter-based correction approach is more efficient than physical intervention methods, as it can be implemented through software control of existing actuators, thereby improving productivity by reducing defective parts while avoiding the need for additional complex mechanical correction devices.

Inventive Principle:
Principle #35Parameter changes

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 real-time defect correction during the build process, reducing waste and costs by ensuring defect-free products and maintaining machine calibration, thereby improving productivity and product quality.

Implementation Method 1

monitoring the sequential layer with a defect analysis subsystem to detect whether the sequential layer has any defects

Methodology Applied
Scientific EffectThermal imaging: Thermography

Data Source

PatentUS11724315B2Systems and methods for defect detection and correction in additive manufacturing processes
Publication Date: 2023.08.15 SENTIENT SCIENCE CORP
  • US11724315B2 patent drawing
  • US11724315B2 patent drawing
  • US11724315B2 patent drawing

AI summary

A system and method of additive manufacturing is disclosed herein which when run or performed form a product with a powder-based additive manufacturing device by adding sequential layers of material on top of one another. As each sequential layer of material is added, the system and method can include monitoring the sequential layer with a defect analysis subsystem to detect whether the sequential layer has any defects. For a detected defect, it can be determined whether defect correction is required. For a required defect correction, one or more correction parameters for the required defect correction can be identified; and a correction command including the one or more correction parameters can be sent to the additive manufacturing device, the correction command causing the additive manufacturing device to help correct the detected defect in the sequential layer according to the correction parameters prior to moving on to a next sequential layer.