Continuous Motion Fluid Dispenser for Circuit Boards
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Solution Overview
Problem
Existing methods for dispensing fluid materials, such as underfill materials, from jetting dispensers onto circuit boards are inefficient due to stop-and-start motion, leading to increased dispensing time and vibration, which affects accuracy and consistency.
Innovation Solution
A method involving continuous motion of the dispenser along a constant trajectory, with real-time position measurement and correction of dispense locations to minimize spatial errors, and precise timing of fluid dispensing based on servo cycles or timers to ensure accurate deposition of fluid material on a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the jetting dispenser uses stop-and-start motion to dispense fluid material at discrete locations, then the dispenser can accurately position and dispense at each location, but the dispensing time increases and vibration occurs affecting accuracy
Solution Approach 1:
The patent implements continuous motion of the jetting dispenser along the circuit board without stopping between dispense locations. The dispenser maintains constant velocity while the control system predicts future dispense locations based on current position and velocity, triggering dispensing at the appropriate moment during continuous motion. This eliminates acceleration and deceleration cycles, reducing dispensing time while maintaining accuracy through predictive positioning.
2Productivity
If the jetting dispenser moves continuously at constant velocity, then dispensing time is reduced and vibration is minimized, but the complexity of position prediction and timing control increases
Solution Approach 1:
The control system performs preliminary calculations of future dispense locations and timing based on current dispenser position and velocity. By predicting where and when dispensing should occur in advance, the system can trigger dispensing events at the correct moments during continuous motion without requiring complex real-time adjustments or feedback loops during actual dispensing.
Solution Approach 2:
The system continuously monitors the actual position and velocity of the jetting dispenser and uses this feedback to update predictions of future dispense locations. This closed-loop approach allows the control system to maintain accurate timing and positioning despite variations in motion, balancing continuous motion benefits with controlled complexity through adaptive prediction.
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 reduces dispensing time, minimizes vibration, and enhances the accuracy of fluid material deposition by maintaining continuous motion and precise control over the dispenser's position and timing, improving the overall efficiency and reliability of the dispensing process.
Implementation Method 1
A typical jetting system includes an applicator or jetting dispenser with a pneumatically-operated needle having a valve element at one end that is configured to selectively engage a valve seat surrounding a discharge passage. Contact between the valve element and valve seat seals off the discharge passage from a chamber supplied with pressurized fluid material.
Implementation Method 2
The valve element is then moved rapidly toward the valve seat to close the space. The rapid reduction in volume extrudes the fluid material through the discharge passage and a shock wave traveling through the fluid and/or the momentum imparted by the extrusion process causes a droplet of the fluid material to be ejected, or 'jetted,' from an outlet of the discharge passage.
Implementation Method 3
The rapid reduction in volume extrudes the fluid material through the discharge passage and a shock wave traveling through the fluid and/or the momentum imparted by the extrusion process causes a droplet of the fluid material to be ejected, or 'jetted,' from an outlet of the discharge passage.
Data Source
AI summary
Methods for applying fluid materials to a substrate, such as circuit board, while continuously moving the fluid dispenser. Some methods generally involve correcting the dispense location for each of the dispensed amounts of fluid material by executing a statistical comparison of either the predicted and actual landing locations on the substrate, or the predicted and actual positions of the dispenser at each of the dispense locations. Other methods generally involve initiating the dispensing of amounts of the fluid material at dispense locations corrected by a correction factor specified in terms of the servo cycle for the movement of the dispenser or by a correction factor specified in terms of partial servo cycles courtesy of a timer.