FDM Mold Outer Layer Surface Treatment

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Solution Overview

Problem

Fused Deposition Modeling (FDM) is not suitable for creating molds due to its inability to produce smooth surfaces and air-tight structures, which are essential for applications like optical components and silicone molding, where surface roughness and leakage issues hinder the release of replicated parts.

Innovation Solution

A method involving FDM printing with an outer layer and a support structure, where cavities are filled with a filler material and the outer layer undergoes post-treatment to enhance surface smoothness and thermal stability, allowing the creation of molds with improved surface finish and thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If FDM printing is used to create molds, then manufacturing speed and cost are improved, but surface smoothness and air-tightness deteriorate

Engineering Contradiction:
Improvemanufacturing speedVSAvoidsurface smoothness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies post-treatment processes such as heating, solvent dissolution, or coating to modify the surface parameters of the FDM-printed outer layer. These parameter changes transform the rough printed surface into a smooth finish suitable for optical applications, directly resolving the surface smoothness issue while preserving the FDM manufacturing advantages

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure where an outer layer (printed with FDM) encloses an inner support structure. The outer layer is specifically designed and treated to provide smooth surfaces, while the inner structure provides structural support. This composite approach allows the outer layer to achieve the required surface quality without compromising manufacturing efficiency

Inventive Principle:
Principle #40Composite materials

2Productivity

If FDM printing is used to create molds, then manufacturing cost and speed are improved, but thermal stability and structural integrity deteriorate

Engineering Contradiction:
Improvemanufacturing speedVSAvoidthermal stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies post-treatment heating or chemical processes to modify the physical and chemical parameters of the printed material. These treatments enhance the thermal stability and mechanical strength of the outer layer, transforming it from a typical FDM product into a mold-capable structure that can withstand injection molding temperatures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The composite structure with an outer layer enclosing an inner support structure allows the outer layer to be optimized for thermal stability and surface quality, while the inner structure provides additional structural reinforcement. This division of functions enables the mold to achieve the required reliability for injection molding applications

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If FDM printing is used to create molds, then ease of manufacture is improved, but leakage and part release issues worsen

Engineering Contradiction:
Improveease of manufactureVSAvoidair-tightness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies post-treatment processes such as heating, solvent dissolution, or coating to modify the surface parameters of the outer layer. These treatments create a smooth, non-porous surface that prevents leakage and facilitates easy part release, directly addressing the air-tightness issue while maintaining the ease of FDM manufacturing

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The outer layer acts as an intermediary between the FDM printing process and the final mold application. It encloses the support structure and provides the critical air-tight barrier and smooth release surface, mediating the transition from a rough printed structure to a functional mold

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

The method enables the production of molds with sufficient strength and thermal stability for injection molding, achieving smooth surfaces and easy part release, thus facilitating faster and cheaper adaptation for replication methods.

Implementation Method 1

a 3D printing stage with 3D printing with 3D printable material the outer layer and the support structure

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

FDM works on an 'additive' principle by laying down material in layers; a plastic filament or metal wire is unwound from a coil and supplies material to produce a part

Methodology Applied
Scientific EffectExtrusion: Extrusion

Implementation Method 3

optionally at least partly filling the cavities with a filler material

Methodology Applied
Scientific EffectDeposition: Deposition (physical)

Data Source

PatentEP3102391B1Fused deposition modeling based mold for molding and replicating objects, method for its manufacture and fused deposition modeling 3D printer
Publication Date: 2017.07.26 SIGNIFY HOLDING BV
  • EP3102391B1 patent drawingFigure 1~2B
  • EP3102391B1 patent drawingFigure 3A~3B
  • EP3102391B1 patent drawingFigure 4A~4B

AI summary

The invention provides a method for manufacturing a 3D item (10), wherein the 3D item (10) comprises an outer layer (210) and a support structure (220) with cavities (230), wherein the outer layer (210) at least partly encloses the support structure (220), and wherein the method comprises: (a) a 3D printing stage comprising 3D printing with fused deposition modeling (FDM) 3D printable material (201) the outer layer (210) and the support structure (220) and at least partly filling the cavities (230) with a filler material (204); and (b) a post-treatment stage comprising post treating at least part of the outer layer (210) for reducing surface roughness.