Nonmatching Shapes in Layerwise Production for Faster Separation

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Solution Overview

Problem

The existing layerwise production methods for tangible objects, particularly those with varying cross-sections, face challenges in rapid formation due to high internal stresses caused by the need for significant external forces during separation, limiting the types of objects that can be quickly produced.

Innovation Solution

The method employs nonmatching shapes between the solid layer and the construction shape, allowing for reduced pressure differences and adhesion forces during separation, which decreases the external force required for separation, enabling faster production of objects with varying cross-sections by filling the interspace with liquid more quickly and minimizing overshoot during positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If full contacting engagement between solid layer and construction shape is used, then separation requires high external force, but this increases internal stresses and limits production speed

Engineering Contradiction:

Improveproduction speedVSAvoidinternal stresses

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The patent applies asymmetry by using nonmatching shapes between the solid layer and construction shape, where the solid layer has a different geometry than the construction shape. This asymmetric design prevents full contacting engagement during separation, reducing adhesion forces and the external force required, thereby decreasing internal stresses and enabling faster production speeds

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent segments the contact interface by using nonmatching shapes that prevent complete engagement between the solid layer and construction shape. This segmentation of the contact area reduces the total adhesion force, allowing for faster separation with lower external forces and reduced internal stresses in the object

Inventive Principle:

Principle #1Segmentation

2Speed

If high external force is applied for fast separation, then separation speed increases, but internal stresses increase causing deformation or breakage

Engineering Contradiction:

Improveseparation speedVSAvoidobject integrity

Core Design Contradiction:

SpeedVSStrength

Solution Approach 1:

The nonmatching shapes create asymmetric contact that reduces adhesion forces, allowing fast separation to occur with lower external forces. This prevents excessive internal stresses from developing during separation, thereby maintaining object integrity while achieving high separation speeds

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent converts the potentially harmful effect of adhesion forces into a benefit by using nonmatching shapes to control and reduce these forces. The reduced adhesion forces, which would normally require high external forces for separation, are instead used to enable gentle, low-stress separation at high speeds

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Quantity of substance

If matching shapes are used between solid layer and construction shape, then full contacting engagement occurs, but liquid filling of interspace is slow and requires more external force

Engineering Contradiction:

Improveliquid filling speedVSAvoidexternal force for separation

Core Design Contradiction:

Quantity of substanceVSForce

Solution Approach 1:

The nonmatching shapes create asymmetric geometry that prevents full contacting engagement, allowing liquid to quickly fill the interspace between the solid layer and construction shape. This rapid liquid filling reduces the pressure difference that would otherwise require high external forces for separation

Inventive Principle:

Principle #4Asymmetry

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 accelerates both separation and positioning steps in the production process, reducing internal stresses and allowing for the rapid formation of a wider variety of objects, including those with complex geometries.

Implementation Method 1

there exists a pressure difference between the (low) pressure in said interspace and the (high) pressure exerted on the layers of the object under production

Methodology Applied

Scientific EffectPressure difference: Pressure Gradient

Implementation Method 2

solidifying means (9) for solidifying predetermined parts of the liquid (3), the solidifying taking place at least when said parts are in contact with the liquid contacting side (11) of the construction shape (6)

Methodology Applied

Scientific EffectRadiation solidification: Photopolymerisation

Data Source

PatentUS8696971B2Method and system for layerwise production of a tangible object

Publication Date: 2014.04.15 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO

AI summary

A method cycle of a method for layerwise production of a tangible object (5) comprises the successive steps of: solidifying predetermined parts of a liquid so as to obtain a solid layer (14) having a predetermined shape; separating said solid layer from a construction shape (6); and moving, relative to one another, the separated solid layer and the construction shape to a predetermined position relative to one another. Solidifying is carried out such that the solid layer and the construction shape have nonmatching shapes in the sense that all surface portions of a solid layer side (70) that are or have been in contact with a liquid contacting side (11) of the construction shape can not simultaneously be brought in full contacting engagement with the liquid contacting side.