Spray Coating of Surgical Needles for Uniform Silicone Tip Coverage
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Solution Overview
Problem
Conventional batch dipping processes for coating surgical needles with silicone coatings result in defects, inefficiencies, and excessive waste due to handling issues with wet coatings and inadequate penetration performance at needle tips, leading to economic inefficiencies and suboptimal manufacturing outcomes.
Innovation Solution
A novel bulk spray coating apparatus and method that uses a fine mist of silicone coating solution with absorbent paper belts and magnetic engagement to apply uniform, defect-free coatings, eliminating the need for water plugging and reducing solvent content, thereby enhancing needle penetration and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If batch dipping process is used to coat surgical needles with silicone coating, then large number of needles can be coated at once, but coating defects such as globbiness and discontinuity occur due to handling wet coatings
Solution Approach 1:
The patent replaces the mechanical batch dipping process with an automated spray coating system that uses compressed air to atomize and deposit silicone coating material. This substitution eliminates manual handling of wet coatings, preventing globbiness and discontinuity defects while maintaining batch processing capability through automated needle conveyance and spraying sequences.
Solution Approach 2:
The spray coating system allows the coating material to self-deposit onto the needle surfaces through atomized spray patterns controlled by compressed air pressure and nozzle positioning. The system automatically adjusts coating deposition without manual intervention, ensuring uniform application while maintaining high batch productivity.
2Quantity of substance
If conventional batch dipping process is used, then coating can be applied to needle bodies, but coating withdraws from piercing tips due to surface energy and low viscosity
Solution Approach 1:
The spray coating system applies different coating quantities to different regions of the needle. The nozzle positioning and spray pattern are optimized to deliver concentrated coating material specifically to the piercing tip area, while the needle body receives adequate but less intensive coverage. This local quality approach ensures tip coating retention despite the low viscosity and surface energy of the silicone material.
3Ease of manufacture
If batch dipping process is used, then coating can be applied to needles, but excessive silicone coating solution is used leading to economic inefficiency
Solution Approach 1:
The automated spray coating system replaces the immersion-based batch dipping process, allowing precise control of coating material deposition. Compressed air atomization delivers coating material in controlled micro-droplets that are efficiently deposited onto needle surfaces, significantly reducing excess coating solution usage compared to the wasteful immersion and drainage process of batch dipping.
Solution Approach 2:
The system changes the physical parameters of coating application by using compressed air pressure (e.g., 30-50 PSI) to atomize the silicone coating material into fine droplets. This parameter change enables precise control of coating material delivery, reducing waste while maintaining adequate coating coverage on all needles in the batch.
4Productivity
If batch dipping process is used, then coating can be applied to needles, but handling of wet coated needles causes damage to coating integrity
Solution Approach 1:
The automated spray coating system replaces manual handling operations with automated needle conveyance mechanisms. Needles are transported through the coating zone and collected without manual intervention, eliminating the handling-induced damage to wet coatings. The system maintains batch processing efficiency through automated sequences of needle feeding, spraying, and collection.
Solution Approach 2:
The patent introduces an intermediary drying or curing zone between the spray coating application and needle collection. This intermediary step allows the coating to set or partially cure before needles are handled or packaged, preserving coating integrity while maintaining batch processing throughput through continuous automated operation.
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
The solution provides superior needle penetration performance with reduced defects and waste, achieving uniform coatings and improved manufacturing efficiency by minimizing the use of silicone coating solutions and eliminating the need for the water-plugging step, resulting in a more robust and cost-effective process.
Implementation Method 1
At least one spray nozzle is moveably mounted over the upper and lower paper conveyors for spraying a silicone lubricious coating onto surgical needles on the upper and lower absorbent belts
Implementation Method 2
The needles are conveyed over an absorbent paper belt which absorbs excess coating material from the needles
Implementation Method 3
a second magnetic end roll for engaging needles
Data Source
AI summary
Novel apparatus and methods for coating surgical needles in batch processes are disclosed. The apparatus and methods are particularly useful for applying uniform silicone lubricious coatings to surgical needles in bulk quantities using a novel separation and spray coating system and method.