Multichannel Printhead Pneumatic Actuation for Viscous Fluids
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Solution Overview
Problem
Current printheads are unable to efficiently handle fluids with medium viscosity (up to 1 Pas) and particles of up to 0.3 mm size at high frequencies (kHz range) with a pitch smaller than 4 mm, while maintaining a lightweight and leak-proof design for mobile printing applications.
Innovation Solution
A printhead with multiple electrically addressable channels utilizing a micro-electro-pneumatic circuit to convert low-energy electrical control signals into high-energy pneumatic control pressures, actuating pneumatically controlled fluid ejectors for precise fluid discharge, enabling efficient printing or dispensing of fluids with varying viscosities and particle sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluid displacement principle is used for high-frequency printing, then droplet rate in kHz range is achieved, but fluid viscosity is limited to below 25 mPas
Solution Approach 1:
The patent employs pneumatic actuators (diaphragms) to generate the forces needed for fluid ejection. By using compressed gas to actuate the diaphragms, the system can generate sufficient force to eject viscous fluids (up to 1 Pas) at high frequencies (kHz range), overcoming the limitation of conventional fluid displacement methods that work only with low-viscosity fluids.
2Adaptability or versatility
If valve technology with electromagnetic or piezoelectric actuators is used for viscous fluids, then fluid viscosity up to 1 Pas is handled, but switching energies become too high for practical implementation
Solution Approach 1:
The system uses pneumatic actuators driven by compressed gas instead of high-energy electromagnetic or piezoelectric valves. The compressed gas provides the necessary force to switch fluid flow for viscous materials, but with significantly lower energy consumption than conventional valve technology, making the system practical for portable and continuous operation.
Solution Approach 2:
The pneumatic system operates in periodic cycles, alternating between charging the diaphragm with compressed gas to eject fluid and releasing to refill the chamber. This periodic operation allows efficient handling of viscous fluids at high frequencies without requiring excessive energy input, as the compressed gas reservoir provides energy on demand in controlled pulses.
3Manufacturing precision
If multi-channel printhead with small pitch is designed, then printing resolution is improved, but device weight increases
Solution Approach 1:
The printhead is divided into multiple independent channels, each with its own pneumatic actuator and fluid pathway. This segmentation allows for compact arrangement of channels with small pitch (down to below 1 mm) while keeping each individual component small and lightweight. The modular structure enables high printing resolution without proportionally increasing overall device weight.
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
Enables the printing or dispensing of fluids with viscosities up to 1 Pas and particle sizes of up to 0.3 mm at kHz frequencies, achieving precise control and high efficiency with a compact, lightweight design suitable for mobile devices.
Implementation Method 1
each channel converting an electrical control signal into a pneumatic control pressure pc of greater energy by using a micro-electro-pneumatic-circuit
Implementation Method 2
the control pressure actuating a diaphragm of a fluid ejector so that as a consequence of a resulting fluid displacement or a resulting release of a valve opening a fluid discharge is effected
Data Source
AI summary
A multichannel printhead for mixing purposes is presented, comprising a first set of fluid outlets each outlet discharging an amount of a first fluid, a second set of fluid outlets each outlet discharging an amount of a second fluid, whereby corresponding outlets of the first and second set are configured to internally or externally lead together and mix the fluids, and whereby at least the fluid discharge of the first set of fluid outlets is controlled by drop-on-demand fluid ejectors responsive to control signals.