Stent Coating Apparatus Preventing Web Formation
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Solution Overview
Problem
Current stent coating methods face issues with web or bridge formation between linear struts, leading to mechanical dysfunction and wastage of expensive medications, which can cause blood flow obstruction and increase costs.
Innovation Solution
A method involving a controlled application route for coating materials on stent struts, using a combination of precise positioning and movement techniques to ensure uniform thickness and prevent web or bridge formation, with a coating apparatus that includes a mandrel with concave portions to prevent coating material from turning around and forming uneven layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the dipping method is used to apply coating liquid on stent, then the coating can be applied uniformly, but web or bridge formation occurs at space portions between linear struts
Solution Approach 1:
The stent surface is segmented into linear strut portions and space portions between struts. The coating application process is divided into separate handling for these regions: the linear struts receive coating through controlled deposition, while the space portions are treated differently to prevent web formation. This segmentation allows precise control over coating distribution and prevents harmful bridging between struts.
Solution Approach 2:
Different coating characteristics are applied to different regions of the stent. The linear strut portions receive coating with specific viscosity and deposition parameters to ensure uniform coverage, while the space portions between struts are treated with adjusted parameters to prevent coating accumulation and web formation. This local differentiation ensures optimal coating quality without harmful effects at any specific location.
2Object-generated harmful factors
If the spraying method is used to apply coating liquid on stent, then web or bridge formation is prevented, but large amount of coating liquid is wasted
Solution Approach 1:
The coating application process incorporates real-time feedback mechanisms to monitor coating deposition on the stent surface. Sensors detect coating presence and quantity, allowing the system to adjust coating liquid delivery dynamically. This feedback control ensures coating is applied only where needed on linear struts, preventing wastage while maintaining uniform coverage and preventing web formation at space portions.
Solution Approach 2:
The coating liquid parameters (viscosity, flow rate, deposition speed) are dynamically adjusted based on the stent geometry and coating requirements. By changing these parameters in real-time during the coating process, the system optimizes coating liquid utilization - applying sufficient coating to linear struts while minimizing deposition in space portions, thereby reducing wastage without compromising coating quality or causing web formation.
3Manufacturing precision
If the coating liquid is applied by scanning method, then the coating can be applied along the pattern shape, but the amount of medicinal solution cannot be set correctly
Solution Approach 1:
The mechanical scanning method is replaced with a coordinated movement system that combines positional control with deposition control. Instead of moving a scanner across the stent surface, the system uses precisely controlled movement of coating application elements along with real-time quantity control mechanisms. This substitution allows accurate coating along the stent pattern while maintaining precise control over the amount of medicinal solution applied, resolving the contradiction between pattern accuracy and quantity control.
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 method allows for rapid, uniform, and efficient application of therapeutic substances onto stent surfaces, reducing re-stenosis ratios and minimizing material wastage, thereby enhancing the mechanical function of stents and reducing patient burden and costs.
Implementation Method 1
a method of applying a coating material (C) to linear struts (S) of a medical device (stent)
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
When a coating material C is applied from a nozzle 38 of an applicator head 30 along struts S of a stent W in which space portions O are formed between linear struts S extending continuously, there are concerned a coating method and a coating apparatus which apply the coating material C continuously from the applicator head 30 directed to the surface of the strut S, and it is possible to form a coating layer having a uniform thickness extremely accurately without generating a web and a bridge at a space portion of the medical device.