Fiber-Reinforced FDM Dispensing Head With Radiant Substrate Preheating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The mechanical properties of 3D-printed parts in continuous fiber reinforced fused deposition modeling (FDM) are limited by high void volume and incomplete welding due to insufficient heating of polymers, leading to mechanical failure points and material clogging in the nozzle.
Innovation Solution
A dispensing head with a solid radiation body that pre-heats the substrate surface using a wide range of wavelengths, thermally separated from the dispensing outlet, ensuring efficient heating of the substrate to above the critical sintering temperature without heating the dispensing head, thereby preventing voids and incomplete bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the polymer is heated above its critical sintering temperature to achieve proper bonding, then the interlayer bonding strength is improved, but the material in the dispensing head may clog due to excessive heating
Solution Approach 1:
The heating function is segmented into two separate locations: (1) an internal heater within the dispensing head that heats the polymer to extrusion temperature, and (2) a radiation heater beneath the substrate that heats the substrate and deposited material to sintering temperature. This segmentation allows each heater to operate at its optimal temperature without causing clogging in the material passage.
Solution Approach 2:
The substrate acts as an intermediary heat transfer medium. The radiation heater heats the substrate, which then transfers heat to the deposited polymer material, achieving sintering temperature without directly heating the material passage or extruded material to excessive temperatures that would cause clogging.
2Use of energy by moving object
If the substrate is pre-heated using a laser at a single wavelength, then the heating efficiency is improved for specific materials, but the method becomes material-dependent and lacks versatility
Solution Approach 1:
The radiation heater is designed to emit across a broad spectrum of wavelengths rather than a single wavelength. This multi-wavelength capability allows the heater to effectively heat various polymer materials with different absorption characteristics, making the process material-independent while maintaining heating efficiency.
Solution Approach 2:
The radiation heater's emission spectrum is changed from a narrow single-wavelength laser to a broad-spectrum radiation source. This parameter change in the radiation characteristics enables effective heating of diverse materials without requiring material-specific optimization.
3Duration of action of moving object
If the polymer residence time at high temperature is extended to improve bonding, then the interlayer diffusion is enhanced, but the material in the nozzle may degrade or clog
Solution Approach 1:
The thermal processing is segmented into two distinct zones: the dispensing head where material is heated only to extrusion temperature with brief residence time, and the substrate zone where material is heated to sintering temperature for extended bonding. This spatial segmentation allows extended high-temperature exposure only where bonding occurs, not in the nozzle.
Solution Approach 2:
The substrate is pre-heated to sintering temperature before material deposition. This preliminary heating action ensures that when material is deposited, it immediately experiences the high temperature needed for bonding, extending the effective residence time at sintering temperature without requiring the material to remain in a hot nozzle.
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 achieves strong interlayer bonding and prevents material clogging, resulting in improved mechanical properties and material independence across various substrate materials.
Implementation Method 1
A dispensing head with a solid radiation body that pre-heats the substrate surface using a wide range of wavelengths
Implementation Method 2
a material heating unit for liquefying the material
Data Source
AI summary
The present document relates to a dispensing head for continuous fiber reinforced fused filament type additive manufacturing. The dispensing head is configured for dispensing a material onto a substrate carrier platform, and comprises one or more inlets for receiving a strand of meltable solid material and a reinforcement fiber and a material passage extending from the receiving inlets to a dispensing outlet. The dispensing head further comprises a material heating unit for liquefying the material and drive means for driving the material through the material passage. The material heating unit comprises a solid radiation body extending from the dispensing outlet at least in a direction parallel to the substrate carrier platform, defining a radiation face toward the substrate carrier platform, wherein the radiation body is thermally separated from the dispensing outlet.