Additive Manufacturing Build Thickness Control via Position Feedback

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Solution Overview

Problem

Conventional additive manufacturing methods face challenges in maintaining accurate relative positions between the working surface and the resin surface, leading to errors in build layer thickness and final part dimensions due to variations in layer thickness and incorrect starting positions.

Innovation Solution

An additive manufacturing apparatus and method that measures the relative positions of the working surface and resin surface, adjusting the build layer thickness to correct for errors and ensure precise final dimensions by using a measuring system to determine the actual positions and modify the build profile accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional additive manufacturing methods are used without measurement and adjustment, then the manufacturing process is simple and fast, but the manufacturing precision deteriorates due to accumulation of errors in build layer thickness

Engineering Contradiction:
Improvebuild layer thickness accuracyVSAvoidapparatus complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by measuring the relative position of the working surface and resin surface before the curing step, and using this measurement to adjust the build layer thickness in advance. The controller modifies the distance the stage will move based on the measured position, preventing error accumulation before it occurs in the final part dimensions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback by using a measuring system to continuously monitor the relative position between the working surface and resin surface, then feeding this information back to the controller which adjusts the build layer thickness accordingly. This closed-loop control system corrects deviations in real-time, maintaining manufacturing precision without requiring complex mechanical adjustments.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If the stage starting position is not accurately determined, then the manufacturing process can start immediately, but the manufacturing precision deteriorates due to incorrect starting position leading to erroneous build layer thickness

Engineering Contradiction:
Improvestarting position accuracyVSAvoidtime for position determination
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by determining the starting position of the stage and measuring the relative position of the working surface and resin surface before the additive manufacturing cycle begins. This preliminary measurement and adjustment ensures accurate build layer thickness from the first layer, preventing error propagation throughout the entire build process.

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the resin layer thickness is not accurately controlled, then the resin deposition process is simple and fast, but the manufacturing precision deteriorates due to incorrect resin layer thickness causing variations in build layer thickness

Engineering Contradiction:
Improveresin layer thickness accuracyVSAvoiddeposition speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent implements feedback by measuring the relative position between the working surface and resin surface, which indirectly monitors the resin layer thickness. The controller uses this feedback information to adjust subsequent build layer thickness measurements, compensating for variations in resin layer thickness without requiring slow, precise control of the deposition process itself.

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 solution reduces the number and magnitude of errors in build layer development, resulting in improved accuracy and precision of final part dimensions by accurately defining the thickness of each layer, preventing malformation and damage during the additive manufacturing process.

Implementation Method 1

an additive manufacturing apparatus (10) that measures the relative positions of the working surface (75) and the resin surface (77)

Methodology Applied
Scientific EffectOptical detection: Optical Tweezers

Implementation Method 2

A resin is deposited as a layer having a desired thickness onto a flexible radiotransparent tape... Radiant energy is used to cure the resin through the radiotransparent tape

Methodology Applied
Scientific EffectPhotopolymerisation: Photopolymerisation

Data Source

PatentEP3927523B1Method and apparatus for build thickness control in additive manufacturing
Publication Date: 2024.10.16 GENERAL ELECTRIC CO
  • EP3927523B1 patent drawingFigure 1
  • EP3927523B1 patent drawingFigure 2
  • EP3927523B1 patent drawingFigure 3~5

AI summary

A method for forming a part (74) layer by layer using an additive manufacturing apparatus (10). The additive apparatus (10) includes a resin support (190), a stage (14), a measuring system (76), and an actuator (32) to change the relative position of the stage (14) and the resin support (190). The method includes: performing an additive manufacturing cycle including: depositing an uncured layer of resin (110); moving the stage (14) to a target location; curing the uncured layer (110); and moving the stage (14) away from the target location; repeating the additive manufacturing cycle; performing a measuring process including the following steps: using the measuring system (76) to take a measurement indicative of an actual position of a structure; comparing the actual position of the structure to an expected position of the structure to determine an error; and using the error to modify the target location.