Stencil Printer Shuttle Assembly for Parallel Inspection
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Solution Overview
Problem
Current stencil printing processes for surface-mount printed circuit boards face inefficiencies in cycle time and quality control, particularly in aligning and inspecting circuit boards, and in cleaning and reusing stencils, which can lead to defects like shorts or inadequate solder paste distribution.
Innovation Solution
A stencil printer design that integrates a single drive assembly for synchronized movement of the print head and stencil shuttle, enabling simultaneous vision inspection and stencil cleaning, while allowing the stencil to translate for efficient cleaning and alignment, thus optimizing the printing and inspection processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential operations are used for stencil cleaning and circuit board inspection, then each process can be performed thoroughly, but the cycle time increases
Solution Approach 1:
The system enables continuous operation by allowing the stencil cleaning process and circuit board inspection process to occur simultaneously and continuously without interruption. The automated shuttle mechanism ensures that while one process is occurring, the other can proceed without waiting, maintaining continuous productive action throughout the system.
Solution Approach 2:
The stencil is cleaned in advance during the inspection phase of the circuit board, preparing it for the next printing operation. This preliminary cleaning action ensures that the stencil is ready for subsequent use while the inspection is still in progress, eliminating waiting time for the next cycle.
2Productivity
If the stencil is cleaned immediately after printing, then cleaning efficiency improves, but the inspection process must wait
Solution Approach 1:
The system introduces a temporal dimension to the process by staggering the timing of cleaning and inspection operations. Instead of one process blocking the other, they are scheduled in different time slots within the same operational cycle, allowing both to proceed without mutual interference.
Solution Approach 2:
By overlapping the cleaning and inspection operations in time, the system maintains continuous productive action. The automated shuttle ensures that cleaning begins immediately after printing while inspection follows without interruption, maximizing the utilization of both processes throughout the cycle.
3Device complexity
If manual alignment and inspection processes are used, then system complexity is reduced, but manufacturing precision and productivity decrease
Solution Approach 1:
The vision system performs automatic alignment and inspection without requiring manual intervention. The system uses fiducial markers on the circuit board to automatically determine position and orientation, eliminating the need for operator skill and time while maintaining high precision. The automated shuttle also self-manages the coordination between printing, cleaning, and inspection operations.
Solution Approach 2:
Manual mechanical alignment operations are replaced with an optical vision system that uses image processing to determine circuit board position and orientation. This substitution eliminates manual labor while achieving higher precision through digital measurement and automated calculation of alignment parameters.
Data Source
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AI summary
A stencil printer (10) includes an electronic substrate support (22) configured to support an electronic substrate (24) and move the electronic substrate between a lowered position and a raised position. The stencil printer further includes a stencil shuttle assembly (18) configured to support a stencil (16) and to move the stencil 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 printer further includes a print head (20) configured to engage the stencil to dispense a material onto the substrate during a print stroke. The stencil printer further includes a drive assembly configured to move the print head (20) to perform the print stroke and configured to selectively move the stencil shuttle assembly (18) between the first and second positions.