Plunger Gap Control in Droplet Ejectors for Particle-Safe Ejection
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Solution Overview
Problem
Existing droplet ejecting devices using a reciprocating plunger face issues such as particle crushing due to plunger abutment on the inner wall of the liquid chamber, leading to clogging and inconsistent ejection amounts due to variations in fluid properties and mixing.
Innovation Solution
The device employs a plunger configuration that maintains a gap with the inner wall of the liquid chamber, controlling displacement to stabilize pressure and prevent particle crushing, using a piezoelectric actuator to adjust ejection amounts by controlling plunger movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the plunger abuts on the inner wall of the liquid chamber to eject droplets, then the ejection force is sufficient, but the solder particles are crushed and clog the nozzle
Solution Approach 1:
The plunger surface is designed with a specific curvature radius that is larger than the nozzle curvature radius, creating a dimensional relationship where the plunger operates in a broader spatial envelope. This dimensional mismatch prevents the plunger from making contact with the nozzle inner wall during reciprocating motion, thereby avoiding particle crushing while still maintaining sufficient ejection force through proper pressure control.
2Reliability
If the plunger does not abut on the inner wall to prevent particle crushing, then particle integrity is maintained, but the ejection amount becomes inconsistent due to fluid property variations
Solution Approach 1:
The invention controls the curvature radius parameter of the plunger surface to be larger than that of the nozzle, fundamentally changing the geometric parameters of the system. This parameter adjustment ensures non-contact operation while maintaining stable pressure transmission to the liquid, thereby achieving consistent ejection amounts without particle crushing.
3Measurement precision
If the plunger operates close to the nozzle for precise ejection control, then ejection precision is improved, but the risk of particle crushing increases
Solution Approach 1:
By designing the plunger curvature radius to be larger than the nozzle curvature radius, the invention creates a dimensional buffer zone that allows the plunger to operate close to the nozzle for precise ejection control without making contact. This dimensional relationship ensures that the plunger tip approaches but does not touch the nozzle inner wall, maintaining ejection precision while eliminating particle crushing risk.
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
Stable ejection of particles without crushing, maintaining consistent ejection amounts despite changes in fluid properties or environments, and preventing pressure loss.
Implementation Method 1
using a piezoelectric actuator to adjust ejection amounts by controlling plunger movement
Data Source
AI summary
Droplet ejecting device (1) includes liquid chamber (12) that stores a liquid to be ejected from nozzle (10) inside, and plunger (11) that advances and retracts inside liquid chamber (12). A distance between a distal end of plunger (11) and a bottom surface inside liquid chamber (12) is larger than a maximum distance between a side surface of plunger (11) and an inner surface of liquid chamber (12) at a position where plunger (11) advances most toward nozzle (10).