Liquid Treatment Apparatus with Staggered Injection for Uniform Substrate Exposure
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Solution Overview
Problem
Existing fluid treatment apparatuses for substrates, such as printed circuit boards, are ineffective in treating substrates with liquid due to 'dragout' issues, particularly with awkward features like holes, and do not provide uniform exposure to treatment liquids.
Innovation Solution
The apparatus features upper and lower plates with a gap forming a treatment zone, with equal up- and down-stream portions for liquid flow, and transverse slots in the plates for staggered liquid injection, ensuring even liquid distribution and exposure to both edges of the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If fluid jet injectors are positioned closer to the entrance edge to reduce dragout, then fluid flows quickly out at the entrance edge, but treatment effectiveness deteriorates
Solution Approach 1:
The treatment zone is segmented into multiple sections with injectors positioned at different locations along the plate length. This allows different regions to serve different functions: upstream regions for initial treatment and downstream regions for ensuring complete coverage, resolving the contradiction between quick fluid exit and effective treatment.
Solution Approach 2:
The invention transitions from a single-row injector arrangement to a two-dimensional grid pattern of injectors distributed across the plate surface. This spatial distribution ensures that fluid is delivered uniformly across the entire substrate width and length, maintaining treatment effectiveness while controlling dragout through optimized positioning.
2Loss of substance
If injectors are positioned to bias flow towards the entrance edge, then dragout is improved, but uniform exposure to treatment liquid deteriorates
Solution Approach 1:
The injector array is segmented into multiple rows and columns, with each segment contributing to uniform coverage. The segmentation allows the system to simultaneously achieve directed flow for dragout control and distributed coverage for uniformity, as each segment serves a specific zone of the treatment area.
Solution Approach 2:
Different regions of the plate have locally optimized injector configurations. The local density and positioning of injectors are adjusted to account for variations in fluid flow patterns across the plate, ensuring that each local area receives appropriate treatment while maintaining overall uniformity.
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 allows for improved treatment of substrates with liquids, achieving steady flow and effective chemical reactions, such as silver electroless plating, across a wide range of conditions, and is effective even when the slot-to-plate distance is reduced or the board speed approaches the liquid flow speed.
Implementation Method 1
means for pumping liquid to each nozzle means to fill the gap both up- and down-stream from the nozzle means to their up- and down-stream edges in normal use
Implementation Method 2
the liquid flows substantially equally to both edges and the sheet material is exposed to the liquid for treatment substantially equally in both portions
Data Source
AI summary
Treatment apparatus has up-stream rollers 2 and down-stream rollers 3. Between the rollers are provided a pair of upper and lower treatment zone plates 4,5, spaced by a gap 6 through which sheet material to be treated can be passed. The plates have grooves 9 occupied by strips defining up- and down-stream even slots 14,15 for flow of treatment liquid into the gap 6. The ends of the upper plate 4 are smoothly rounded at 37. When sheet material is fed into the gap flow occurs on top of the sheet and up over the rounded edge of the plate. Then it flows sideways off the top of the plate without flowing over the top of the upper rollers.