PCB Screen Printing Vacuum Control for Stable Solder Deposition
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Solution Overview
Problem
Conventional screen printing machines for circuit boards require operator-adjusted negative pressure to ensure accurate solder deposition, leading to inconsistent printing quality due to smaller component distances and hole sizes, necessitating a solution that stabilizes negative pressure without manual adjustment.
Innovation Solution
A screen printing machine equipped with a sensor to detect pressure inside a closed space beneath the circuit board and a control device to adjust negative pressure, allowing for stable pressure control based on set values, eliminating the need for operator-adjusted negative pressure settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If negative pressure generator is used to ensure screen mask is flush against circuit board, then printing accuracy is improved, but solder smearing occurs when negative pressure is too large
Solution Approach 1:
The patent employs a feedback control mechanism where a sensor detects the actual negative pressure value in real-time, and the control device adjusts the negative pressure generator's output based on this detected value to maintain the optimal pressure range. This closed-loop feedback system prevents both excessive pressure (causing solder smearing) and insufficient pressure (causing poor flush contact), thereby resolving the contradiction between printing accuracy and solder quality.
2Manufacturing precision
If operator adjusts negative pressure manually based on experience, then some printing quality can be achieved, but adjustment work requires a lot of time and consistency is poor
Solution Approach 1:
The system implements self-service automation where the control device automatically manages negative pressure adjustment based on sensor feedback, eliminating the need for manual operator intervention. The system self-regulates the negative pressure within the optimal range, consistently achieving high printing quality without requiring operator time or experience-based adjustments, thus resolving the contradiction between printing quality and adjustment time.
3Quantity of substance
If negative pressure is increased to print more solder, then solder quantity is improved, but solder smearing worsens
Solution Approach 1:
The patent utilizes parameter change control by dynamically adjusting the negative pressure parameter within an optimal range rather than using fixed high pressure. The control device modifies the negative pressure parameter based on real-time sensor feedback to achieve the precise balance needed for adequate solder quantity without causing smearing, resolving the contradiction between solder quantity and solder quality.
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 configuration ensures consistent solder deposition on circuit boards by maintaining appropriate negative pressure levels, improving printing quality and reducing operator workload by automating pressure adjustments.
Implementation Method 1
a negative pressure generator connected to the space of the box member and configured to create negative pressure inside the space
Implementation Method 2
a sensor configured to detect a pressure inside the space
Data Source
AI summary
A screen printing machine configured to print solder onto a surface of a circuit board using a screen mask. The screen printing machine is provided with: a screen mask arranged at a top side of the circuit board; a box member arranged at an underside of the circuit board including a space that is closed by the circuit board; a negative pressure generator connected to the space of the box member and configured to create negative pressure inside the space; a sensor configured to detect a pressure inside the space; and a control device configured to control the negative pressure generator based on the pressure detected by the sensor.