Phase Change Ink Printing System Using Composite Waveforms
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Solution Overview
Problem
Existing 3D printing systems using phase change inks are limited by the speed of printing, as they require multiple printheads to achieve faster production, which increases complexity and cost.
Innovation Solution
A 3D printing system utilizing a drop on demand piezo (DODP) printhead with an array of piezoelectric actuators, capable of generating two different drop volumes of phase change ink using distinct operating mode waveforms, allowing for a single piezo nozzle to produce both nominal and large drop volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple printheads are used to increase printing speed, then productivity is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies parameter changes by modifying the electrical waveform parameters (voltage magnitude, pulse width, frequency) to generate different drop volumes from a single printhead. The controller varies waveform parameters dynamically to produce nominal drops during traversal and composite drops during dwell periods, achieving variable material deposition without adding hardware complexity
Solution Approach 2:
The patent implements periodic action through the scanning motion of the printhead across the build plate. The controller periodically switches between generating nominal drops during traversal and composite drops during dwell periods, creating a rhythmic pattern of deposition that increases productivity while maintaining single-printhead simplicity
2Productivity
If multiple printheads are used to increase printing speed, then productivity is improved, but cost increases
Solution Approach 1:
The patent applies universality by designing a single printhead system that performs multiple functions: it generates both nominal drops for rapid traversal printing and composite drops for detailed feature deposition. The same piezoelectric actuators and nozzle assembly handle both drop types by receiving different waveform signals, eliminating the need for multiple specialized printheads and reducing system cost
3Device complexity
If a single printhead is used to maintain system simplicity, then device complexity is reduced, but productivity decreases
Solution Approach 1:
The patent applies dynamics by making the printhead system adaptive and variable in its operation. The controller dynamically adjusts waveform parameters in real-time based on the printhead's position and the required feature type, allowing a single static physical printhead to perform the work of multiple fixed printheads. This dynamic control enables rapid switching between drop sizes to maintain high productivity
4Productivity
If large drop volumes are used to reduce printing time, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the drop generation process into two distinct modes: nominal drops for general area coverage and composite drops for precise feature definition. The controller segments the printing process into traversal phases (using nominal drops) and dwell phases (using composite drops), allowing each drop type to optimize for its specific function and maintaining overall precision while improving productivity
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 enables a significant speed increase in 3D printing without adding complexity or hardware, by allowing the same printhead to produce drops of two sizes, thus maintaining uniform scan speed and accuracy.
Implementation Method 1
The DODP printhead includes an array or arrayed plurality of piezoelectric (piezo) actuators
Implementation Method 2
Phase change inks are solid at room temperature or about 25 degrees Celsius. These inks are handled at elevated temperatures in the printing system to facilitate providing the ink to the printhead and ejection. Because they solidify upon impact, these inks do not tend to flow from defined lateral boundaries after dispensing.
Implementation Method 3
The operation of the array of piezo actuators includes, for individual ones of the array of piezo actuators and individual ones of the ink drops: apply a secondary waveform to the piezo actuator including a secondary positive voltage pulse having a maximum magnitude (VSP) followed by a negative voltage pulse having a maximum magnitude (VSN)
Data Source
AI summary
A 3D printing system includes a build plate supporting a 3D article, a drop on demand piezo (DODP) printhead, a horizontal movement mechanism, a supply of phase change ink, and a controller. The controller is configured to: operate the supply and the DODP printhead to maintain a liquid state of the phase change ink, position an upper surface of the 3D article at a build plane, scan the printhead over the upper surface, and operate the DODP printhead to deliver ink drops to pixel locations upon the upper surface. The operation of the DODP printhead includes, for individual ones of the ink drops: apply a secondary waveform to a piezo actuator followed by a primary waveform to the piezo actuator to generate two drops of liquified phase change ink that merge in flight before reaching and solidifying on the upper surface.