Piezoelectric Dispenser Eliminates Z-Axis Movement for Viscous Material
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Solution Overview
Problem
Existing dispensing systems for viscous materials on substrates, such as printed circuit boards, are inefficient due to the time required for the dispenser to lower and raise, known as z-axis movement, which contributes to the overall dispensing time and can cause material to coalesce into a continuous pattern instead of discrete dots.
Innovation Solution
A dispenser system utilizing a piezoelectric actuator assembly with a compliant flexure assembly that allows for precise, rapid up-and-down movement of the piston, enabling efficient dispensing of viscous materials without the need for extensive z-axis movement, and includes a controller for adaptive motion control to maintain desired dispensing profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional auger-type dispensers lower the dispenser unit to wet the circuit board before dispensing, then material adhesion is improved, but dispensing time increases due to the z-axis movement and wetting process
Solution Approach 1:
The patent replaces the traditional mechanical auger-type dispensing system with a piezoelectric actuator-driven piston system. This substitution eliminates the need for z-axis movement and wetting process, achieving rapid material deposition directly onto the substrate without the time-consuming mechanical lowering and raising of the dispenser unit.
Solution Approach 2:
The invention extracts and eliminates the z-axis movement mechanism from the dispensing system. By removing the need for vertical positioning and wetting operations, the system achieves rapid dispensing without the time loss associated with traditional mechanical positioning systems.
2Quantity of substance
If dots are deposited close together to form continuous pattern, then material coverage is improved, but precision is reduced as dots coalesce instead of remaining discrete
Solution Approach 1:
The piezoelectric actuator enables precise periodic control of material ejection, allowing discrete dots to be deposited with exact spacing and timing. This periodic action ensures that dots remain distinct and precisely placed while achieving complete coverage, preventing unwanted coalescence.
Solution Approach 2:
The system utilizes piezoelectric parameter changes to control material ejection volume, velocity, and timing with high precision. By dynamically adjusting these parameters, the system can deposit discrete dots that maintain their individuality while achieving continuous pattern coverage through precise control.
3Productivity
If rapid piston movement is implemented to reduce dispensing time, then productivity is improved, but control precision may deteriorate
Solution Approach 1:
The patent replaces traditional mechanical positioning systems with a piezoelectric actuator that provides both rapid response for high-speed operation and fine control for precise material placement. This substitution enables simultaneous achievement of high productivity and manufacturing precision through the inherent properties of piezoelectric materials.
Solution Approach 2:
The piezoelectric actuator system is designed to be dynamically responsive, allowing rapid changes in piston position and material ejection velocity. This dynamic capability enables the system to maintain precision during high-speed operation by adapting control parameters in real-time to match the rapid movement requirements.
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 system significantly reduces dispensing time and improves precision by allowing the dispenser to maintain consistent nozzle height and efficiently deposit material as discrete dots without coalescing, enhancing the mechanical and environmental characteristics of electronic assemblies.
Implementation Method 1
The actuator is a piezoelectric actuator assembly
Implementation Method 2
The flexure housing includes at least one flexure element configured to enable the compliant assembly to accommodate an arcuate motion of the lever arm
Data Source
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AI summary
A dispenser, configured to dispense material on a substrate, includes a dispensing unit having a housing with a chamber, a piston disposed in the chamber and axially movable within the chamber, and a nozzle coupled to the housing. The nozzle has an orifice co-axial with the chamber of the housing. The dispenser further includes an actuator coupled to the dispensing unit and configured to drive the up-and down movement of the piston, and a compliant assembly coupled to the actuator and the piston. The compliant assembly is configured to permit limited relative travel between the actuator and the piston. A method of dispensing is further disclosed.