Screen Printer Mask Deflection Sensing for Tension Control
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Solution Overview
Problem
Conventional methods for measuring mask tension in screen printers are either expensive, increase the size of the board manufacturing line, or are inconvenient to handle and adjust, as they rely on external devices or reaction force measurements that do not effectively control mask separation after printing.
Innovation Solution
A screen printer is equipped with a mask holding device, a board device, a squeegee device, a mask pressing device with a pusher, a mask measurement device to measure the mask's height, and a tension measurement device to calculate the mask's tension based on the measured height, allowing for precise tension control without the need for external devices.
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 device becomes expensive and the manufacturing line size increases
Solution Approach 1:
The mask tension measurement function is merged with the existing screen printer by integrating a pusher and displacement sensor into the printer's frame. This eliminates the need for separate external measurement devices, reducing overall system complexity and manufacturing line size while maintaining measurement capability
Solution Approach 2:
The screen printer is modified to perform its own mask tension measurement using integrated sensors and actuators. The displacement sensor measures mask deflection caused by the pusher, allowing the printer to self-diagnose mask tension without external measurement equipment
2Measurement precision
If a weight is placed on the mask to apply constant load, then mask displacement can be measured, but the device becomes inconvenient to handle and adjust
Solution Approach 1:
The mechanical weight-based load application system is replaced with a controlled pusher mechanism that can be actuated by a cylinder or motor. This allows for easy adjustment of the applied load through electrical control rather than physical handling of weights, significantly improving ease of operation
Solution Approach 2:
The static weight-based load is replaced with a dynamic, controllable pusher mechanism that can adjust the applied force as needed. This enables flexible load adjustment during different measurement scenarios without requiring physical reconfiguration of weights
3Measurement precision
If reaction force measurement is used to determine mask tension, then tension can be measured, but mask separation after printing cannot be appropriately controlled
Solution Approach 1:
The reaction force measurement method is replaced with direct displacement measurement of the mask. By measuring how much the mask deflects under a known load from the pusher, the system directly quantifies mask tension in terms of deflection, which is the actual parameter affecting mask separation and printing quality
Solution Approach 2:
The measurement parameter is changed from reaction force to mask displacement/deflection. Since mask separation control depends on the physical displacement of the mask rather than the force required to move it, measuring displacement directly provides more reliable correlation with printing quality and mask separation performance
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 configuration enables accurate and convenient tension measurement within the screen printer, preventing printing defects by ensuring proper mask contact and reducing the need for external tension measurement devices, thus maintaining a compact manufacturing line and improving printing quality.
Implementation Method 1
the mask separation of the board is caused by the deflection amount of the mask
Implementation Method 2
a value related to the tension of the mask is calculated by the tension measurement device based on the measured value
Data Source
AI summary
A screen printer that measures a tension of a mask in a machine, 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 travelling device with respect to the mask; a mask measurement device, installed on the upper travelling device or the lower travelling device 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.