Material Jetting Hull-Core Strategy for Layer Flatness
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Solution Overview
Problem
Additive manufacturing processes, particularly Material Jetting, face challenges in achieving flat layers with constant thickness and minimal pore volume due to variations in droplet size, speed, substrate properties, and overhangs, leading to rounding and sagging issues.
Innovation Solution
The implementation of a hull-core strategy during path planning in Material Jetting, where the hull compensates for overhanging regions and uses idle-run loops for high path speeds at corners, eliminating the need for additional measurement equipment and post-processing corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional Material Jetting processes are used to deposit droplets, then manufacturing freedom and tool-free production are achieved, but layer flatness and thickness uniformity deteriorate due to droplet size variations, speed changes, and overhang effects
Solution Approach 1:
The method performs preliminary action by calculating and depositing compensation droplets in advance at locations where material deficiency is expected (such as at the beginning, middle, and end of droplet traces). This pre-compensation approach addresses potential flatness issues before the actual component geometry is finalized, thereby improving layer flatness without compromising manufacturing freedom
Solution Approach 2:
The invention applies local quality by making the droplet deposition process adaptive to local conditions. The system calculates required droplet parameters (size, spacing, position) based on local geometry, path speed variations, and predicted material distribution. This allows different regions of the same layer to have different deposition characteristics, achieving both manufacturing freedom and improved layer uniformity
2Productivity
If path speed is increased to improve productivity, then manufacturing time is reduced, but droplet spacing uniformity and layer quality deteriorate due to speed variations and acceleration effects
Solution Approach 1:
The system implements dynamics by continuously adapting droplet deposition parameters to the instantaneous path speed and acceleration conditions. The printhead controller adjusts droplet size, spacing, and timing in real-time based on the actual motion state of the printhead, enabling high-speed operation while maintaining droplet spacing uniformity and layer quality
Solution Approach 2:
The method employs feedback mechanisms where the actual path position and speed are continuously monitored and used to adjust subsequent droplet deposition parameters. This closed-loop control ensures that even at high speeds, the droplet spacing remains uniform and layer quality is maintained throughout the printing process
3Loss of time
If overhanging regions are manufactured without support structures, then post-processing time and complexity are reduced, but layer flatness deteriorates due to sagging and rounding effects
Solution Approach 1:
The system performs preliminary action by depositing compensation droplets in advance in overhanging regions where material deficiency and sagging are expected. This pre-compensation creates a more uniform layer thickness from the beginning, reducing or eliminating the need for post-processing support removal and maintaining layer flatness without additional time loss
Solution Approach 2:
The invention applies preliminary anti-action by counteracting the expected sagging and rounding effects in overhanging regions through strategic placement of compensation droplets. This preemptive measure opposes the harmful gravitational effects before they can significantly degrade layer quality, enabling support-free manufacturing while maintaining precision
4Manufacturing precision
If droplet size and spacing are varied to compensate for path speed changes, then layer uniformity is improved, but process complexity increases due to dynamic parameter adjustment requirements
Solution Approach 1:
The system implements universality by creating a multi-functional control algorithm that simultaneously handles multiple tasks: calculating droplet positions, determining optimal droplet sizes, adjusting spacing intervals, and compensating for path speed variations. This unified approach improves layer uniformity while avoiding the need for separate complex control systems for each parameter
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 approach ensures layers are as flat and uniform as possible without additional equipment, enabling the production of complex components with overhanging regions without support structures and maintaining desired contours, while maintaining high path speeds and reducing manufacturing complexity and time.
Implementation Method 1
An apparatus that dispenses individual drops based on a control signal is usually referred to as a 'drop-on-demand' (DOD) printhead. An electrical signal is sent to the printhead actuator for each drop to be generated.
Implementation Method 2
In these additive manufacturing processes, the workpieces are built up in layers or in elements based on digital models
Data Source
AI summary
A method for manufacturing a component in layers includes dropwise application of a liquid material using a printhead. More particularly, a layer (14) of the component to be produced is divided into an outer region (20) and a central core region (18), and the liquid material (16) is applied successively in the outer region (20) and the core region (18). One or more parameters relating to the spacing between paths to be traversed, the drop size, the spacing between successive drops, etc. is selected so that the layer (14) will have a thickness that is as uniform as possible.