Stencil Printer Dispenser Integration for Solder Paste Defect Correction
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Solution Overview
Problem
Current surface-mount circuit board manufacturing processes face inefficiencies due to the need for separate machines for printing and dispensing solder paste, leading to increased space requirements and manual intervention for error correction, which disrupts the production line flow.
Innovation Solution
A combination stencil printer and dispenser that integrates a print head for depositing viscous materials, a cleaning assembly for removing excess material, and a dispenser for on-the-fly correction of defects, all controlled by a centralized system to streamline the printing and dispensing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate machines are used for printing and dispensing solder paste, then each machine can be optimized for its specific function, but the production line requires increased space and manual intervention for error correction
Solution Approach 1:
The patent combines the stencil printing mechanism and the dispenser mechanism into a single integrated machine. The printing assembly includes a stencil carrier and squeegee for depositing solder paste, while the dispenser assembly includes a nozzle for precise material placement. Both assemblies share common components such as the substrate support, control system, and housing, thereby reducing production line complexity while maintaining functional optimization
Solution Approach 2:
The integrated machine performs multiple functions within a single device: it can print solder paste through the stencil, dispense precise amounts of material through the nozzle, and correct defects on-the-fly. The controller coordinates these different operations, allowing the machine to adapt to various manufacturing needs without requiring separate specialized equipment
2Reliability
If separate machines are used for printing and dispensing, then specialized functions are maintained, but production line space and operational efficiency are reduced
Solution Approach 1:
By integrating printing and dispensing operations into one machine, the patent eliminates the need for material handling and positioning between separate devices. The substrate remains on the same support table, and the controller manages both operations sequentially without interruption, thereby maintaining material deposition accuracy while improving production throughput
Solution Approach 2:
The integrated design enables continuous operation where the substrate is printed and dispensed upon without removal or repositioning. The controller coordinates the printing assembly and dispenser assembly to operate in sequence, eliminating idle time and maintaining continuous productive action throughout the material deposition process
3Manufacturing precision
If manual intervention is used for error correction, then defect repair is possible, but production line flow is disrupted
Solution Approach 1:
The integrated machine combines printing, dispensing, and defect correction capabilities in one system. When a defect is detected, the controller activates the dispenser assembly to deposit corrective material at the defect location without removing the substrate from the machine, thereby maintaining manufacturing precision while eliminating production interruptions
Solution Approach 2:
The system performs preliminary inspection to identify defects before final processing. Once a defect is detected, the dispenser assembly is immediately activated to correct the issue on-the-fly, preventing the need for later manual intervention and maintaining continuous production flow
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 integrated solution reduces production line complexity, allows for real-time defect correction, and enhances efficiency by combining printing and dispensing operations within a single machine, minimizing interruptions and optimizing equipment utilization.
Implementation Method 1
the circuit board is raised to the stencil by a substrate support, e.g., a table having pins or other work holders. Solder paste is then dispensed by moving a wiper blade or squeegee across the stencil to force the solder paste through apertures formed in the stencil and onto the board
Implementation Method 2
As the squeegee is moved across the stencil, the solder paste tends to roll in front of the blade, which desirably causes mixing and shearing of the solder paste so as to attain a desired viscosity to facilitate filling of the apertures in the screen or stencil
Implementation Method 3
a cleaning assembly is moved under the stationary stencil and excess material is wiped off of the stencil as the cleaning assembly is moved
Data Source
AI summary
A method of depositing viscous material on a substrate includes positioning the substrate in a print position, performing a print operation on the substrate with a print head and a stencil to deposit viscous material on the substrate, and inspecting the substrate with a vision system to detect a defect with the deposit of viscous material on the substrate. The method further includes, in the event of a defect, re-working the substrate by depositing viscous material on the substrate with a dispenser attached to a cleaning assembly, the stencil, or an independent gantry to correct the defect.