Additive Manufacturing Energy Absorbing Layer Bonding
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Solution Overview
Problem
Additive manufacturing methods, such as FDM, face challenges in achieving strong interlayer bonding due to rapid cooling of thermoplastic filaments, leading to inferior strength in polymeric articles, especially under tensile stress, as energy beams struggle to effectively bond cylindrical filaments.
Innovation Solution
A method and device that deposit filaments with an energy-absorbing layer sandwiched between them, using an energy beam to melt and bond the layers, increasing the mechanical strength and cohesion of the polymeric article.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thermoplastic filament is deposited layer-by-layer by FDM method, then additive manufacturing capability is achieved, but interlayer bonding strength deteriorates due to rapid cooling
Solution Approach 1:
The patent applies preliminary action by pre-heating the build plate or previously deposited layers before depositing the new filament layer. This ensures the surface is sufficiently hot to bond with the incoming molten filament, preventing premature cooling and weak bonding. The build plate or prior layers are prepared in advance with thermal energy to facilitate strong adhesion when the new material arrives.
Solution Approach 2:
The patent introduces an intermediary thermal field or heating element that mediates between the molten filament and the previously deposited layer. This intermediary heating mechanism ensures continuous thermal energy transfer at the bonding interface, allowing the hot filament to soften and fuse with the cooler underlying layer, thereby maintaining strong interlayer bonds throughout the printing process.
2Strength
If energy beam is used to weld thermoplastic materials, then bonding between layers is improved, but effectiveness deteriorates on cylindrical filament surfaces due to scattering
Solution Approach 1:
The patent transitions from attempting to precisely target the cylindrical surface in three dimensions to a different approach: using a broad-area heating method or heating the build plate from below. This dimensional change avoids the scattering problem entirely by not relying on precise surface targeting of the cylindrical filament, instead using volumetric or substrate-based heating that naturally covers the entire contact area.
Solution Approach 2:
The patent changes the parameters of the energy beam application by using lower energy density over a larger area, or by changing from a focused beam to a distributed heating source. This parameter change accommodates the cylindrical geometry by providing uniform thermal energy across the entire filament surface without requiring precise point-by-point targeting, thereby maintaining bonding effectiveness despite surface scattering.
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 solution enhances the bonding between filaments, resulting in a solid article with increased mechanical strength and stability, capable of withstanding tensile stress without cracking or detachment, allowing for the production of articles of various sizes and shapes.
Implementation Method 1
In a second step, the filament is at least partially covered by an energy absorbing layer. In a fourth step, an energy beam is directed onto the energy absorbing layer to provide a bond of the filaments and the energy absorbing layer.
Implementation Method 2
an energy beam is directed onto the energy absorbing layer to provide a bond of the filaments and the energy absorbing layer
Implementation Method 3
Due to the fact, that the flowable thermoplastic material cools rapidly after having left the printer head
Data Source
Figure 1
Figure 2~3
AI summary
A method for manufacturing a solid article (10) by an additive manufacturing device (1) comprises a first step of depositing a filament (9) on a base element (2). In a second step, the filament (9) is at least partially covered by an energy absorbing layer (8). In a third step, the energy absorbing layer (8) is at least partially covered by another layer of the filament (9), such that the energy absorbing layer (8) is sandwiched between the filaments (9). In a fourth step, an energy beam (13) is directed onto the energy absorbing layer (8) to provide a bond of the filaments (9) and the energy absorbing layer (8). The additive manufacturing device (1) comprises a base element (2), a filament generation unit (3) for generating the filament (9), a filament supply unit (4), a raw material container (5) containing a raw material (6) to be supplied to the filament generation unit (3), an energy absorbing layer supply unit (7) configured to supply an energy absorbing layer (8) on the filament (9). The energy absorbing layer (8) covers at least a portion of the filament (9). The energy beam (13) can be directed onto the energy absorbing layer (8) to heat the energy absorbing layer (8), such that the energy absorbing layer (8) and the filaments (9) are bonded.