Adhesive Dispensing Valve Control for Consistent Dot Size
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Solution Overview
Problem
Existing adhesive application methods using fast-acting electromagnetically switched valves suffer from deviations in adhesive portion quantities due to remagnetization effects and adhesive viscosity changes, leading to inconsistent dot sizes, which prior methods fail to adequately address.
Innovation Solution
The method involves dynamically shortening the actual opening duration of subsequent valve openings based on valve operating parameters to compensate for electromagnetic interference and viscosity changes, using actuation voltage pulses with adjusted duty cycles to maintain consistent adhesive portion sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If identical actuation voltage pulses are used for each valve opening, then the control process is simple, but the actual quantity of adhesive dispensed deviates from the target quantity due to remagnetization effects and viscosity changes
Solution Approach 1:
The patent applies dynamics by making the actuation voltage pulse dynamic rather than static. The control unit adjusts the actuation voltage pulse parameters (amplitude, duration, shape) based on detected valve operating parameters such as coil temperature and adhesive viscosity. This allows the system to adapt to changing conditions during operation, compensating for remagnetization effects and viscosity changes while maintaining precise control over adhesive portion quantities.
Solution Approach 2:
The patent implements feedback by detecting valve operating parameters (coil temperature, adhesive viscosity) during operation and using this information to adjust subsequent actuation voltage pulses. The control unit continuously monitors the valve's state and modifies the actuation signals accordingly, creating a closed-loop control system that maintains consistent adhesive portion quantities despite changing operating conditions.
2Productivity
If the valve operates for extended periods, then productivity increases, but self-heating of the coil and remagnetization effects cause actual opening duration to extend and adhesive viscosity to decrease
Solution Approach 1:
The patent applies preliminary action by detecting valve operating parameters (such as coil temperature and adhesive viscosity) before applying each actuation voltage pulse and using this information to pre-adjust the pulse parameters. This allows the system to compensate for thermal effects and viscosity changes before they significantly impact the adhesive dispensing, maintaining precision during extended operation.
Solution Approach 2:
The patent implements parameter changes by dynamically modifying the actuation voltage pulse parameters (amplitude, duration, waveform shape) based on detected valve operating conditions. As the valve operates and temperature increases causing coil resistance changes and adhesive viscosity changes, the control unit adjusts the electrical parameters of the actuation pulse to compensate for these changes and maintain consistent adhesive portion quantities.
3Speed
If adhesive viscosity decreases due to heating, then adhesive flows more easily, but the closing element is moved into the open position faster extending the actual opening time
Solution Approach 1:
The patent applies preliminary anti-action by detecting the adhesive viscosity (or parameters indicating viscosity changes) before actuation and adjusting the actuation voltage pulse to counteract the expected effect of viscosity changes. When viscosity decreases and would cause faster closing element movement and extended opening duration, the control unit modifies the pulse parameters in advance to compensate, preventing the deviation before it occurs.
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 effectively counters remagnetization and viscosity-related deviations, ensuring consistent adhesive portion quantities by dynamically adjusting the opening duration of valve openings, thereby improving application precision.
Implementation Method 1
a coil of an electromagnet being energized with an actuation voltage pulse for each successive dispensing of portions of adhesive from the valve
Implementation Method 2
The remagnetization effects mean that, for example, a closing element of the valve moved by the electromagnet opens earlier than would be the case without remagnetization effects
Implementation Method 3
self-heating of the valve coil and the associated reduction in adhesive viscosity
Data Source
AI summary
A method for applying individual portions of adhesive to a substrate, in which the portions of adhesive are applied successively by means of a valve, a coil of an electromagnet being energized with an actuation voltage pulse for each successive dispensing of portions of adhesive from the valve, which causes a valve opening of the valve for an actual opening duration during which adhesive can flow out of the valve for dispensing the respective adhesive portion by moving a closure member of the valve from a closed position into an open position. The actual opening duration of at least one valve opening which follows a valve opening which precedes it in time is shortened in accordance with one or more valve operating parameters to compensate for electromagnetic interference effects which extend the actual opening duration of the subsequent valve opening.