Needleless Viscous Material Dispenser with Voice Coil Piston
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Solution Overview
Problem
Existing dispensing systems for viscous materials on substrates, such as printed circuit boards, require time-consuming 'wetting' processes and have inefficiencies in material delivery due to the need for z-axis movement and inertia-based deposition methods.
Innovation Solution
A dispenser system featuring a gantry-based setup with a piston-driven nozzle assembly that uses a voice coil motor for precise control, allowing for needleless dispensing with controlled volumetric flow and eliminating the need for z-axis lifting by maintaining a consistent nozzle height, thereby reducing the time required for dispensing and improving material distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional auger-type dispensers are used to dispense viscous material, then material can be placed with great accuracy, but the dispenser unit must be lowered and raised (z-axis movement) which contributes to additional time for dispensing operations
Solution Approach 1:
The patent removes the z-axis movement function from the dispensing system. The nozzle is fixed at a constant height above the substrate, eliminating the need to lower and raise the dispenser unit. Material is delivered through a closed cavity system without requiring the nozzle to contact or approach the substrate surface, thus extracting the time-consuming vertical movement while maintaining precision through controlled material ejection.
Solution Approach 2:
The patent replaces the mechanical auger-based dispensing system with a pneumatic or pressure-driven system. Instead of using a rotating auger to force material out, the system uses a cavity under negative pressure that draws material through a delivery passage. This substitution eliminates the mechanical complexity and movement requirements of the auger system while maintaining accurate material placement.
2Reliability
If the dispenser unit is lowered to wet the circuit board prior to dispensing, then material adhesion is improved, but the wetting process contributes to additional time required for dispensing operations
Solution Approach 1:
The system prepares the substrate surface in advance by applying a release agent or primer coating that creates optimal adhesion conditions. This preliminary action eliminates the need for real-time wetting during the dispensing operation, allowing material to be deposited immediately with proper adhesion properties without the time-consuming wetting step.
Solution Approach 2:
The patent introduces an intermediary substance (release agent or primer) that mediates between the substrate and the viscous material. This intermediary layer is applied in advance and provides the necessary adhesion properties, eliminating the need for the nozzle to wet the surface during dispensing operations.
3Productivity
If dots of viscous material are ejected with sufficient inertia to separate from the nozzle, then material can be deposited without wetting, but controlling the precise volume and placement requires careful inertia management
Solution Approach 1:
The system incorporates feedback control mechanisms that monitor material flow and adjust delivery parameters in real-time. Sensors detect the volume and placement of deposited material, and the control system adjusts pressure, cavity volume, or delivery timing to maintain precise control. This feedback loop enables high-speed dispensing while maintaining accurate volume control without relying solely on inertia-based ejection.
Solution Approach 2:
The system uses dynamic control of the delivery cavity pressure and volume to regulate material flow. Rather than relying on fixed inertia parameters, the system dynamically adjusts the negative pressure in the cavity and the timing of material ejection to achieve precise volume control at high speeds. This dynamic approach allows adaptation to varying material properties and dispensing 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 enables efficient, precise, and rapid dispensing of viscous materials with controlled volume and velocity, reducing operational time and improving the accuracy of material placement on substrates without the need for z-axis movement, enhancing the overall dispensing process.
Implementation Method 1
A voice coil motor is used to drive the piston
Implementation Method 2
The piston is configured to move between a pre-dispense position and a dispense position within the chamber... The dispenser is constructed such that a volume of viscous material dispensed from the dispensing bore is substantially equal to the volume of the piston entering the dispensing bore
Data Source
AI summary
A dispenser for dispensing a volume of viscous material on a substrate includes a frame, a gantry system coupled to the frame, and a dispenser unit coupled to the gantry system. The dispenser unit includes a housing having a chamber and a piston disposed in the chamber. The piston is configured to move between a pre-dispense position and a dispense position within the chamber. The dispenser unit further includes a dispensing bore configured to receive the piston therein and a nozzle coupled to the housing. A controller is coupled to the piston to control the operation of the piston. The dispenser is constructed such that a volume of viscous material dispensed from the dispensing bore is substantially equal to the volume of the piston entering the dispensing bore when moving the piston to the dispense position. Other embodiments and methods of dispensing viscous material are further disclosed.