Thin-Wall Geometry Adjustment in 3D Printing

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Solution Overview

Problem

Layered deposition systems face challenges in reproducing CAD model geometries with thin-wall regions, leading to overfill conditions and poor part quality due to limitations in wall thickness reproduction.

Innovation Solution

The host computer modifies the geometry of thin-wall regions by adjusting the positions of polyline segments to achieve a threshold wall width, ensuring that the deposited build material does not overlap and maintain the quality of the 3D object, using techniques such as generating secondary vertices and adjustment vectors to adjust segment locations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the CAD model geometry with thin-wall regions is directly used for layered deposition, then the manufacturing precision of wall thickness is improved, but overfill conditions occur and part quality deteriorates

Engineering Contradiction:
Improvewall thickness reproductionVSAvoidoverfill condition
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The host computer performs preliminary modification of the CAD model geometry before the layered deposition process. Specifically, it identifies thin-wall regions and adjusts their wall thickness to be equal to or greater than a predetermined threshold value, preventing overfill conditions during subsequent build operations

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the geometric parameters of thin-wall regions by modifying wall thickness values. The host computer calculates adjusted coordinates for vertices and control points of polylines representing thin-wall regions, transforming the original geometry into a modified geometry with increased wall thickness that prevents overfilling

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the wall thickness of thin-wall regions is increased to prevent overfilling, then the reliability of the build process is improved, but the manufacturing precision of the original design geometry deteriorates

Engineering Contradiction:
Improvebuild process stabilityVSAvoidoriginal design geometry accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention applies local modification only to thin-wall regions identified in the CAD model, while leaving other regions unchanged. The host computer selectively processes polylines corresponding to thin-wall regions by calculating adjusted coordinates, ensuring that only necessary geometric changes are made to prevent overfilling without affecting the overall design integrity

Inventive Principle:
Principle #3Local quality

3Productivity

If the deposition head moves at high speed to improve productivity, then the build time is reduced, but the precision of road deposition deteriorates leading to potential overfilling

Engineering Contradiction:
Improvebuild speedVSAvoidroad deposition accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The host computer performs preliminary geometry modification to increase wall thickness of thin-wall regions before generation of toolpaths. This pre-adjustment ensures that even at high deposition speeds, the increased wall thickness provides sufficient margin to prevent overfilling, allowing the deposition head to maintain higher speeds without sacrificing precision

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2176805B1Method for building three-dimensional objects with thin-wall regions
Publication Date: 2019.11.13 STRATASYS INC
  • EP2176805B1 patent drawingFigure 1
  • EP2176805B1 patent drawingFigure 2
  • EP2176805B1 patent drawingFigure 3

AI summary

A method for modifying a computer-aided design model of a three-dimensional object, the method comprising establishing a threshold wall width, providing at least one sliced layer polyline of the computer-aided design model, determining a first distance between first and second portions of the at least one sliced layer polyline, and adjusting locations of the first and second portion to provide a second distance if the first distance is less than the threshold wall width, where the second distance is about equal to the threshold wall width, or greater.