Screen Printing Paste Ejection Control for Waste Reduction
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Solution Overview
Problem
High viscosity paste in screen printing machines often results in incomplete ejection, leading to waste when the detector reaches a predetermined pressing-down limit position, causing leftover paste in the container.
Innovation Solution
A screen printing machine with a paste supply apparatus that includes a pot holder, an ejecting member, and a detector, where the ejecting member continues to press down after reaching the predetermined press-down limit position to ensure complete paste ejection from the container.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ejecting member is pulled upward out from the container when the detector detects the pressing-down limit position, then paste pot exchange is enabled, but waste paste is generated due to incomplete ejection
Solution Approach 1:
The ejecting member continues to press down the inner lid for a predetermined time period after the detector detects the pressing-down limit position, before being pulled upward. This preliminary continuation action ensures complete paste ejection by overcoming the high viscosity of the paste, preventing waste paste from remaining in the container when the paste pot is exchanged.
2Loss of time
If the ejecting member is pulled upward immediately when the detector detects the limit position, then time is saved for paste pot exchange, but paste remains in the container causing waste
Solution Approach 1:
The system performs a preliminary continuation of the pressing action for a predetermined time period after detection, ensuring complete paste ejection before initiating the paste pot exchange sequence. This resolves the contradiction by optimizing both time efficiency and paste utilization.
Solution Approach 2:
The detector provides feedback on the pressing-down limit position, and the control system uses this feedback to automatically extend the pressing duration for a predetermined time period, ensuring complete ejection without requiring manual intervention or estimation.
3Loss of substance
If the ejecting member presses down the inner lid for extended duration, then complete paste ejection is achieved, but the paste pot exchange process is delayed
Solution Approach 1:
The ejecting member continues pressing for a predetermined time period after detection, which is the minimum necessary duration to ensure complete paste ejection of high viscosity paste. This predetermined time is optimized to achieve complete ejection while minimizing delay to the paste pot exchange process.
Solution Approach 2:
The pressing duration is changed from an immediate stop at detection to an extended duration by adding a predetermined time period. This parameter change ensures complete paste ejection while the system optimizes the overall process timing to minimize impact on paste pot exchange efficiency.
Data Source
AI summary
A screen printing machine includes a paste supply apparatus which supplies paste on a mask by using a paste pot including an inner lid movable in a container. The paste supply apparatus includes: a pot holder which holds the paste pot such that a through hole of the container faces downward; an ejecting member which abuts on the inner lid of the paste pot; an ejecting member lifting unit which presses down the ejecting member to eject the paste from the through hole; and a detector which detects a state in which the ejecting member reaches a predetermined press-down limit position in the container. After the detector detects the state in which the ejecting member reaches the press-down limit position in the container, the ejecting member lifting unit continues to press down the ejecting member to further eject the paste.