Screen Printer Mask Tension Measurement Using Laser Deflection
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Solution Overview
Problem
Conventional screen printers face issues with mask tension measurement, leading to printing defects due to inadequate control over mask separation, as external devices are expensive, increase production line size, and are inconvenient to handle and adjust.
Innovation Solution
A screen printer with a mask holding device, squeegee device, mask pressing device, and integrated mask measurement device that measures the height of the deflected mask using a laser displacement meter, allowing for precise tension calculation and compact line integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an external mask tension measurement device is used, then mask tension can be measured, but the production line size increases and cost increases
Solution Approach 1:
The patent combines the mask tension measurement function with the existing screen printer by installing the measurement device on the lower travelling device. This integration allows the printer itself to measure mask tension without requiring a separate external measurement device, thereby maintaining measurement capability while avoiding increase in production line size.
Solution Approach 2:
The lower travelling device, which already exists for moving the imaging device, is given an additional function by installing the mask measurement device on it. This multi-functional approach allows the same structural component to serve both as a travel mechanism and as a measurement platform, eliminating the need for separate dedicated measurement equipment.
2Measurement precision
If a weight is placed on the mask to apply constant load, then mask tension can be measured, but the device becomes inconvenient to handle and adjust
Solution Approach 1:
The patent replaces the mechanical weight-based load application system with a pneumatic system. An air cylinder is used to apply vertical load to the mask through the pusher, allowing for easier adjustment and control of the load by simply regulating air pressure rather than physically changing weights.
Solution Approach 2:
The invention uses pneumatic actuation via an air cylinder to apply the vertical load to the mask. This pneumatic system provides smooth, adjustable, and easily controllable force application, replacing the cumbersome mechanical weight system while maintaining accurate measurement capability.
3Measurement precision
If reaction force measurement with a push rod is used, then mask tension can be determined, but mask separation cannot be appropriately controlled
Solution Approach 1:
The patent measures mask tension by detecting vertical displacement (height change) of the mask in the vertical dimension rather than measuring horizontal reaction force. A displacement sensor detects the vertical movement of the mask when pressed by the pusher, providing more reliable correlation to mask separation behavior during printing.
Solution Approach 2:
The invention replaces the reaction force measurement approach with a displacement measurement approach using a displacement sensor. This substitution measures the actual deformation of the mask rather than the force required to deform it, providing more direct information about mask tension and its effect on separation.
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
Enables accurate mask tension measurement within the printer, preventing printing defects by ensuring consistent mask contact, reducing production line size, and simplifying load adjustment, thus improving printing quality and operational efficiency.
Implementation Method 1
a mask measurement device; and a tension measurement device configured to calculate a tension of the mask based on a measured value of the mask measurement device wherein the mask measurement device is configured to measure a height of the mask
Data Source
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AI summary
There is provided a screen printer capable of measuring a tension of a mask in a machine, the screen printer including: a mask holding device configured to hold a mask; a board device configured to position a board from below with respect to the mask held by the mask holding device; a squeegee device configured to apply and spread a cream solder on an upper surface of the mask; a mask pressing device configured to press the mask at a set pressure by a pusher which is installed on an upper travelling device or a lower travellilng device with respect to the mask; a mask measurement device, being installed on the upper travelling device or the lower travelling device so as to be opposed to the pusher, which is configured to measure a height of the mask; and a tension measurement device configured to calculate a tension of the mask based on a measured value of the mask measurement device.