Component Solder Paste Printing With Laser Transfer and Gap Control
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Solution Overview
Problem
Current surface mount technology (SMT) solder paste printing processes are prone to defects due to inaccuracies in stencil thickness, aperture size, blade angle, and printing speed, and jet printing of viscous solder paste is limited by clogging and debris issues, leading to inefficiencies in the assembly process.
Innovation Solution
A system and method for jet printing solder paste directly onto electronic components during the 'pick and place' stage using a laser-based printing system with a well-defined gap control and imaging for monitoring, allowing for high-resolution and high-speed printing, and enabling the use of a coating system that creates a uniform layer on a donor substrate before transferring it to the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If screen-printing through stencil is used to apply solder paste, then solder paste can be deposited on PCB pads, but defects occur due to stencil thickness variations, aperture size inaccuracies, and blade pressure issues
Solution Approach 1:
The patent replaces the mechanical screen-printing system with a jet printing system that uses controlled material ejection. Instead of relying on stencil apertures and blade pressure, the system jets solder paste directly onto component leads through precise control of material ejection, eliminating stencil-related defects and achieving more consistent deposition accuracy.
Solution Approach 2:
The patent uses imaging systems to capture the actual positions and dimensions of PCB pads and component leads, then creates a digital model for guidance. This copying approach allows the jet printing system to adapt to actual variations in the physical system, compensating for manufacturing tolerances and ensuring accurate solder paste placement.
2Productivity
If jet printing is used to print viscous solder paste, then printing speed can be increased, but clogging and debris issues occur
Solution Approach 1:
The patent modifies the physical state parameters of solder paste by adjusting temperature and viscosity control. By heating the solder paste to reduce viscosity during jetting, the system achieves higher printing speeds without clogging. The temperature and viscosity are carefully controlled to maintain jetting reliability while enabling faster production.
Solution Approach 2:
The patent implements imaging systems and control algorithms that continuously monitor the jetting process. The system captures images of deposited solder paste, measures its dimensions and position, and uses this feedback to adjust jetting parameters in real-time. This closed-loop control prevents clogging by detecting and correcting issues before they cause failures.
3Productivity
If high printing speed is used in screen-printing, then productivity increases, but insufficient solder paste is applied due to reduced contact time
Solution Approach 1:
The patent replaces the mechanical screen-printing process with jet printing, where solder paste is ejected directly onto the target. This eliminates the need for prolonged contact time between the printing mechanism and the substrate. The jetting process deposits the required amount of solder paste in a single, controlled action, allowing high printing speeds without compromising deposition accuracy.
Solution Approach 2:
The patent uses imaging systems to pre-measure the dimensions and positions of target areas before printing. The control system calculates the exact amount of solder paste needed and prepares the jetting parameters in advance. This preliminary action ensures that the correct amount of material is deposited at high speed, eliminating the trade-off between speed and precision.
4Quantity of substance
If stencil aperture size is increased to improve solder paste application, then more solder paste is applied, but solder bridge shorts occur
Solution Approach 1:
The patent uses imaging systems to capture the exact dimensions and positions of PCB pads and component leads. The control system creates a digital model that precisely defines the target area for solder paste deposition. This copying approach allows the system to apply the exact amount of solder paste needed for each specific geometry, preventing both insufficient solder and solder bridge shorts by matching the deposition pattern to the actual physical layout.
Solution Approach 2:
The patent implements location-specific control of solder paste deposition parameters. The jet printing system adjusts material ejection parameters based on the specific characteristics of each target area, such as pad size, shape, and spacing to adjacent pads. This local quality control ensures optimal solder paste amount for each location, preventing solder bridges while ensuring adequate wetting.
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 approach minimizes defects by ensuring accurate and robust placement of solder paste on electronic components, enhancing the efficiency and quality of the surface mount assembly process while avoiding issues associated with traditional screen-printing and jet printing methods.
Implementation Method 1
a laser-based printing unit that prints dots of the solder paste from the coated substrate onto the electronic component
Data Source
AI summary
Systems and methods in which dot-like portions of a material (e.g., a viscous material such as a solder paste) are printed or otherwise transferred onto an electronic component at a first printing unit, and the electronic component is subsequently placed onto a substrate with the portions of viscous material between the electronic component and the substrate. Optionally, a printing unit which prints the dots of material onto the electronic component includes a coating system that creates a uniform layer of the material on a donor substrate, and the material is transferred in the individual dot-like portions from the donor substrate onto the electronic component by the printing unit. The system may also include imaging units to aid in the overall process.