3D Printing Structure With Monomer Injection For Strength

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Solution Overview

Problem

Conventional 3D printing methods face limitations in producing delicate contours and achieving mechanical strength due to the need for objects to remain stable until polymerization, and the use of reinforcing fibers can lead to nozzle blockages and interface weaknesses.

Innovation Solution

A method involving the creation of a printing structure using 3D printing to define an interior space, which is then filled with a liquid or pasty monomer that is polymerized in one piece, decoupling the precision of the printed structure from the filling material's mass flow and allowing for the use of reinforcing fibers without nozzle blockages, while ensuring the polymerization occurs without interfaces that can weaken the final object.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If reinforcing fibers are added to the printing material to increase strength, then the mechanical strength of the object is improved, but the nozzle may become blocked and the object structures must remain stable until polymerization

Engineering Contradiction:
Improvemechanical strengthVSAvoidnozzle blockage risk
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The process is divided into two separate stages: first printing the structure without fibers, then injecting the fiber-reinforced monomer into the printed structure. This segmentation allows the nozzle to remain clear during printing while still achieving fiber reinforcement in the final product.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The printing structure is manufactured in advance as a fiber-free framework that defines the interior space. This preliminary structure provides the necessary geometric stability before the fiber-containing filling material is introduced, eliminating the need for fibers to be present during the printing process.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If a nozzle with a small outlet opening is used to produce delicate structures, then the manufacturing precision is improved, but the mass flow through the outlet is limited and filling takes a very long time

Engineering Contradiction:
Improvedelicate structure precisionVSAvoidfilling speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The system separates the precision function (performed by the small nozzle during printing) from the filling function (performed by the injection process). The printing structure with its small features is created first with high precision, then the interior is filled using a different process that is not constrained by nozzle size limitations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The printed structure acts as an intermediary that defines the interior space and guides the filling material. It transfers the precision requirements to the printing phase while allowing the filling phase to use higher mass flow rates through the injection system.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the object structures must remain independently stable until polymerization, then the structural integrity during printing is maintained, but this limits the types of delicate contours that can be achieved

Engineering Contradiction:
Improvestructural stabilityVSAvoiddelicate contour capability
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

A preliminary printing structure is created that provides just enough stability to support the printing process and define the interior space, but does not need to support the full mechanical loads that the final polymerized object will bear. This allows for more delicate contours than would be possible if the printing material itself needed to provide full structural support.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The printing structure serves as a temporary intermediary framework that guides the monomer injection and defines the final object's geometry. It provides structural support during manufacturing but is not required to maintain the final object's mechanical integrity, which is achieved through polymerization of the injected monomer.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 method enables the production of finer and more complex object structures with increased mechanical strength, as the polymerization process occurs without interfaces, and the use of reinforcing fibers enhances isotropic mechanical properties, allowing for the creation of both delicate and robust objects quickly and efficiently.

Implementation Method 1

A filling material, which comprises at least one liquid or pasty monomer, is then introduced into the interior. Finally, the monomer is polymerized into a polymer.

Methodology Applied
Scientific EffectPolymerization: Photopolymerisation

Data Source

PatentEP3541603B13-d printing method having increased strength of the produced object
Publication Date: 2023.12.06 ROBERT BOSCH GMBH
  • EP3541603B1 patent drawingFigure 1
  • EP3541603B1 patent drawingFigure 2a
  • EP3541603B1 patent drawingFigure 2b

AI summary

The invention relates to a method (100) for producing a three-dimensional object (10), having the following steps: a printing structure (11), which defines an interior (12), is produced (110) from a printing material (21) by means of 3-D printing; a filling material (22), which comprises at least one liquid or pasty monomer (23), is introduced (120) into the interior (12); the monomer (23) is polymerized (130) to form a polymer (24). The invention further relates to a 3-D printer (30) for performing the method (100), wherein a first printing head (31) for the printing material (21) and a second printing head (32) for the filling material (22) are provided, wherein the outlet opening (32a) of the second printing head (32) for the filling material (22) has a cross-sectional area that is greater than that of the outlet opening (31a) of the first printing head (31) for the printing material (21) by a factor of at least 2, preferably by a factor of at least 5, and/or a base plate (33) is provided, on which the printing structure (11) should be constructed, wherein the base plate (33) has a feed-through (34) for the filling material (22), which feed-through can be connected, on the side facing away from the printing structure (11), to a pressurized source (26) for the filling material (22).