Oscillating Stencil Shuttle for SMT Printer Cleaning

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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 efficiently, and ensuring precise deposition of viscous materials like solder paste.

Innovation Solution

A stencil printer with a stencil shuttle assembly that moves the stencil in an oscillating manner in the y-axis direction, utilizing multiple actuators for precise alignment and a dual-action wiping motion to enhance cleaning, allowing simultaneous vision inspection and stencil cleaning during the printing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stencil is cleaned and the circuit board is inspected separately, then the quality inspection is thorough, but the cycle time increases

Engineering Contradiction:
Improvequality inspectionVSAvoidcycle time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The stencil shuttle assembly performs oscillating motion in the y-axis direction, creating periodic dual-action wiping movements that enable thorough cleaning while maintaining efficient cycle time through rhythmic, coordinated operations

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The stencil cleaning and circuit board inspection operations are performed simultaneously and continuously during the stencil translation phase, eliminating idle time and ensuring both quality assurance and production efficiency occur without interruption

Inventive Principle:
Principle #20Continuity of useful action

2Ease of manufacture

If a single-axis wiping motion is used, then the wiping mechanism is simple, but the cleaning effectiveness is insufficient

Engineering Contradiction:
Improvewiping mechanism simplicityVSAvoidcleaning effectiveness
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The stencil shuttle assembly converts single-axis linear motion into dual-axis oscillating motion through coordinated actuator operation, creating a dynamic wiping action that enhances cleaning effectiveness while maintaining mechanical simplicity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The wiping motion is extended from a single linear dimension to two dimensions through y-axis oscillation, allowing the wiper to engage the stencil surface at multiple positions and angles for more effective material removal

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Stability of the object's composition

If the stencil remains stationary during printing, then the printing process is stable, but the cleaning and inspection operations cannot be performed in parallel

Engineering Contradiction:
Improveprinting stabilityVSAvoidparallel operations capability
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The printing process is segmented into distinct phases: a stable printing phase where the stencil is stationary, and a translation phase where the stencil moves for cleaning and inspection, allowing both stability and parallel operations to be achieved in different temporal contexts

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The stencil shuttle assembly alternates between stationary positioning during printing and oscillating motion during cleaning/inspection, creating periodic cycles that maintain printing stability while enabling parallel productivity-enhancing operations

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3307540B1Dual action stencil wiper assembly for stencil printer
Publication Date: 2020.02.26 ILLINOIS TOOL WORKS INC
  • EP3307540B1 patent drawingFigure 1
  • EP3307540B1 patent drawingFigure 2
  • EP3307540B1 patent drawingFigure 3

AI summary

A stencil printer (10) includes a stencil shuttle assembly (18) coupled to a frame (12). The stencil shuttle assembly is configured to move the stencil (16) 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 (18) further is configured to move the stencil (16) in a y-axis direction to align the stencil. The stencil printer further includes a wiper (164) to remove material from the stencil as the stencil is translated away from the substrate (24) by the stencil shuttle assembly. The stencil shuttle assembly, when the stencil is translated away from the substrate, is configured to move the stencil (16) in the y-axis direction in an oscillating manner. Methods of cleaning a stencil are further disclosed.