Jetting Dispenser Needle Position Control With Piezo Feedback
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Solution Overview
Problem
Maintaining consistent reciprocal needle movement in jetting systems over time is challenging due to material wear, environmental changes, and part tolerances, leading to inconsistent dot size and shape of jetted material.
Innovation Solution
A method involving a piezoelectric device actuated by a voltage waveform, with position sensing and feedback control to determine and apply a required voltage waveform for precise needle movement, ensuring consistent dispensing operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a piezoelectric device is used to actuate the needle for jetting material, then the response speed and control level are improved, but the consistency of needle movement over time deteriorates due to material wear, environmental changes, and part tolerances
Solution Approach 1:
The patent implements a feedback control system where a position sensor continuously monitors the actual position of the needle during dispensing operations. The controller compares the actual position with the desired position and dynamically adjusts the voltage waveform applied to the piezoelectric device to compensate for deviations caused by wear, environmental changes, and tolerances. This closed-loop feedback mechanism maintains reliable and consistent needle movement over time while preserving the fast response characteristics of the piezoelectric actuator.
2Manufacturing precision
If dynamic correction of needle stroke is implemented through feedback control, then the manufacturing precision of jetted dots is improved, but the device complexity increases due to additional sensors and control systems
Solution Approach 1:
A position sensor and controller form a feedback loop that continuously monitors needle position and adjusts the voltage waveform to the piezoelectric device. This ensures consistent dot size and shape by compensating for positional deviations in real-time, directly improving manufacturing precision despite the added system complexity.
Solution Approach 2:
The patent replaces complex mechanical adjustment mechanisms with an electronic feedback control system. Instead of physically adjusting the piezoelectric device or needle mechanism to account for wear and tolerances, the system uses electronic sensing and signal processing to dynamically correct needle position, reducing mechanical complexity while improving precision.
3Manufacturing precision
If a position sensor and feedback control system are added to monitor and adjust needle position, then the manufacturing precision and reliability are improved, but the device complexity and cost increase
Solution Approach 1:
The feedback control system uses a position sensor to monitor needle position and a controller to adjust the voltage waveform applied to the piezoelectric device. This closed-loop approach significantly improves needle position accuracy and manufacturing precision, justifying the additional components through enhanced product quality and consistency.
Solution Approach 2:
The patent substitutes complex mechanical positioning and adjustment mechanisms with an electronic feedback control system. The electronic system senses needle position and dynamically adjusts actuation signals, achieving superior precision with fewer moving parts and reduced mechanical complexity compared to traditional mechanical adjustment systems.
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 allows for dynamic correction of needle stroke, maintaining consistent dot size and shape of jetted material by continuously monitoring and adjusting the voltage waveform based on real-time positional data, improving the precision and reliability of the jetting process.
Implementation Method 1
actuating a piezoelectric device operatively connected to a needle by providing a voltage waveform to the piezoelectric device, such that the moving part translates along a positional path
Data Source
AI summary
Systems and methods of controlling movement of a moving part of an applicator for jetting material from the applicator are disclosed. The method includes actuating a piezoelectric device operatively connected to a needle by providing a voltage waveform to the piezoelectric device, such that the needle translates along a positional path in a first dispensing operation. The method also includes sensing positions of the moving part over a period of time, where the positions define a time-dependent positional profile of the moving part, and receiving parameters for a second dispensing operation. The method also includes determining a required voltage waveform to be applied to the piezoelectric device to perform the second dispensing operation, and adjusting the voltage waveform provided to the piezoelectric device to match the required positional profile.