Compression Roller Geometry for Uniform Additive Manufacturing Layers
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Solution Overview
Problem
Existing additive manufacturing methods face issues with uniform layer deposition, air trapping, and material gouging during layer bonding, leading to weakened parts and increased machining time due to unsatisfactory use of oscillating plates and grooved rollers.
Innovation Solution
A compression roller with a flat center and elliptically tapered ends is used to flatten and level molten material layers, ensuring smooth bonding and navigation around corners without gouging or dragging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an oscillating plate is used to flatten and level the deposited material, then the material can be compressed to some extent, but the plate causes material distortion and gouging during directional changes, leading to increased machining time
Solution Approach 1:
The patent changes the geometric parameters of the compression tool from a flat oscillating plate to a roller with a specific radius of curvature that matches the bead radius. This parameter change allows the roller to conform to the deposited material shape, eliminating gouging and distortion while maintaining compression effectiveness, thereby reducing machining time.
Solution Approach 2:
The invention introduces a curved roller surface with a radius of curvature substantially equal to the radius of curvature of the deposited bead. This curvature allows the roller to smoothly navigate directional changes without creating sharp edges or gouges, eliminating the need for subsequent machining operations.
2Manufacturing precision
If a grooved roller is used to compress the material, then some compression is achieved, but the grooves cause material distortion and prevent uniform layer deposition
Solution Approach 1:
The patent employs a roller with a homogeneous, smooth outer surface without grooves or variations. This homogeneous surface ensures uniform compression across the entire bead width, producing consistent layer thickness and uniform material density, which directly improves bonding strength between layers.
Solution Approach 2:
The invention changes the surface geometry parameter of the compression roller from grooved to smooth, with a specific radius of curvature matching the bead. This parameter change eliminates material distortion caused by grooves while maintaining effective compression, resulting in uniform layer deposition and enhanced bonding.
3Productivity
If a flat compression roller is used, then material can be compressed, but the roller creates sharp edges and gouges at directional changes, requiring additional machining
Solution Approach 1:
The patent applies a curved roller surface with a radius of curvature substantially equal to the radius of curvature of the deposited bead. This curvature allows the roller to smoothly follow directional changes in the toolpath, eliminating sharp edges and gouges while maintaining high deposition speeds, thus improving surface quality without sacrificing productivity.
Solution Approach 2:
The invention optimizes the roller's geometric parameters, specifically setting the radius of curvature to match the bead radius. This parameter optimization enables the roller to conform to the material shape during directional changes, producing smooth surfaces that meet final part specifications without requiring additional machining operations.
4Force
If the roller radius of curvature does not match the bead radius of curvature, then compression is achieved, but material distortion occurs during directional changes
Solution Approach 1:
The patent precisely matches the roller's radius of curvature to the bead's radius of curvature. This parameter matching ensures that the compression force is applied uniformly across the material without creating stress concentrations or distortion, particularly during directional changes. The matched curvature allows the roller to conform to the material shape while maintaining structural integrity.
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 achieves uniform layer deposition with minimal air trapping, enhancing bonding strength and reducing machining time by preventing material distortion during directional changes.
Implementation Method 1
comprises a process of melting a very thin layer of a flowable material (e.g., a thermoplastic material), and applying this material in layers
Implementation Method 2
a roller configured to compress the deposited flowable material, wherein the roller comprises: a flat center portion having a constant diameter
Data Source
AI summary
An additive manufacturing device and method for delivering a flowable material from a nozzle of a programmable computer numeric control (CNC) machine and compressing the flowable material with a compression roller. In one embodiment, the device includes a nozzle configured to deposit a flowable material on a surface; and a roller configured to compress the deposited flowable material, wherein the roller comprises: a flat center portion having a constant diameter; and opposed end portions, wherein each end portion extends outwardly from the flat center portion, and wherein a radially outermost surface of each end portion is angled relative a rotational axis of the roller.