Dual-Action Stencil Wiper for SMT Printer Cycle Time Reduction
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Solution Overview
Problem
Current stencil printing processes for surface-mount printed circuit boards face challenges in reducing cycle time while maintaining quality, particularly in aligning and cleaning stencils and inspecting circuit boards, which can lead to inefficiencies and inconsistencies in solder paste deposition.
Innovation Solution
A stencil printer with a stencil shuttle assembly that moves in both x-axis and y-axis directions, coupled with a vision system and actuators for precise alignment and a dual-action wiping motion for efficient stencil cleaning, allows for simultaneous inspection and cleaning operations, reducing cycle time and improving stencil wiping effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the stencil is cleaned and the circuit board is inspected sequentially, then each process can be performed thoroughly, but the cycle time increases and productivity decreases
Solution Approach 1:
The stencil is made movable in the y-axis direction, adding a new dimension of motion to the cleaning process. This allows the stencil to oscillate back and forth during cleaning, enabling the wiper to access different areas of the stencil surface and improve cleaning effectiveness without extending the overall cycle time significantly
2Reliability
If the stencil wiper applies strong pressure to remove solder paste, then cleaning effectiveness improves, but the risk of damaging the stencil or circuit board increases
Solution Approach 1:
The stencil is made dynamically movable in the y-axis direction during the cleaning process. This dynamic motion allows the wiper to apply consistent pressure while the stencil oscillates, preventing the wiper from sticking or applying excessive localized force that could damage the stencil or circuit board, while still achieving effective cleaning
3Device complexity
If the stencil is held stationary during cleaning, then the cleaning path is simple, but the cleaning effectiveness is reduced due to limited relative motion between wiper and stencil
Solution Approach 1:
The stencil is transformed from a stationary object to a dynamically movable one during cleaning. The stencil shuttle assembly enables the stencil to oscillate in the y-axis direction while being cleaned, creating enhanced relative motion between the wiper and stencil surface that significantly improves cleaning effectiveness without requiring a complex multi-axis wiper mechanism
Data Source
AI summary
A stencil printer includes a stencil shuttle assembly coupled to a frame. The stencil shuttle assembly is configured to move the stencil in an x-axis direction between a first position in which the stencil is positioned toward a front of the stencil printer and a second position in which the stencil is positioned toward a back of the stencil printer. The stencil shuttle assembly further is configured to move the stencil in a y-axis direction to align the stencil. The stencil printer further includes a wiper to remove material from the stencil as the stencil is translated away from the substrate by the stencil shuttle assembly. The stencil shuttle assembly, when the stencil is translated away from the substrate, is configured to move the stencil in the y-axis direction in an oscillating manner. Methods of cleaning a stencil are further disclosed.