Sterilizable Polymeric Knob Assembly for Endoscopic Cameras
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Solution Overview
Problem
The existing methods for manufacturing medical device components, such as endoscopic camera knob assemblies, are costly and inefficient, with high material usage, complex machining requirements, and difficulties in achieving precise and cosmetic-quality components using traditional metal machining and plastic injection molding processes, which also fail to withstand high-temperature steam sterilization effectively.
Innovation Solution
A method involving the use of plastic injection molding to create near-net shape components, followed by spin-welding and machining to eliminate flash and undesirable molding characteristics, and the use of a unique polymeric material that mimics metallic appearance and withstands sterilization, along with metal injection molding to reduce costs and enhance precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional metal machining and plastic injection molding are used to manufacture knob assemblies, then manufacturing precision and cosmetic quality can be achieved, but manufacturing costs and time increase significantly
Solution Approach 1:
The knob assembly is divided into multiple components (knob body, cap, internal ring, magnets) that are manufactured separately using optimized processes and then assembled. This segmentation allows each component to be manufactured using the most appropriate process for its specific requirements, improving overall manufacturing efficiency while maintaining precision.
Solution Approach 2:
Near-net shape components are manufactured using injection molding and metal injection molding (MIM) processes before final assembly. These preliminary manufacturing steps create components that are close to their final dimensions, requiring minimal post-processing machining and reducing overall manufacturing time while maintaining precision.
2Manufacturing precision
If traditional metal machining is used to manufacture knob assemblies, then precise components can be produced, but material usage and manufacturing costs increase
Solution Approach 1:
Near-net shape components are manufactured using injection molding and metal injection molding (MIM) processes before final assembly. These preliminary manufacturing steps create components that are close to their final dimensions, requiring minimal post-processing machining and reducing overall manufacturing time while maintaining precision.
Solution Approach 2:
The invention transitions from traditional metal machining to metal injection molding (MIM) process, changing the manufacturing parameter from subtractive machining to near-net shape forming. This parameter change dramatically reduces material waste while maintaining the ability to produce precise components with complex geometries.
3Productivity
If plastic injection molding is used to manufacture knob assemblies, then manufacturing costs and time are reduced, but undesirable surface features and sterilization resistance are compromised
Solution Approach 1:
The cap component is designed to cover and hide the injection molding gate and any associated surface defects on the internal ring. By extracting the cosmetic requirement from the internal ring and placing it on the external cap, the design allows use of efficient injection molding processes while maintaining high surface quality where visible.
Solution Approach 2:
The knob assembly uses composite construction with plastic components (knob body, cap) and metal components (internal ring, magnets) manufactured using different optimized processes. The plastic parts use injection molding for efficiency, while the metal parts use MIM for precision, creating a composite assembly that achieves both productivity and surface quality.
4Ease of manufacture
If plastic materials are used for knob assemblies, then manufacturing costs are reduced, but resistance to high-temperature steam sterilization is insufficient
Solution Approach 1:
The knob assembly uses composite construction with plastic components (knob body, cap) and metal components (internal ring, magnets) manufactured using different optimized processes. The plastic parts use injection molding for efficiency, while the metal parts use MIM for precision, creating a composite assembly that achieves both productivity and surface quality.
Solution Approach 2:
The plastic knob body and cap are designed as disposable or single-use components that can withstand the sterilization process. By using inexpensive plastic materials that can survive sterilization, the design allows cost-effective manufacturing while ensuring the components maintain their functionality and appearance after sterilization.
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 approach significantly reduces manufacturing time and costs, minimizes undesirable surface features, and ensures the components maintain their appearance and functionality under sterilization, offering a versatile solution for various medical device components.
Implementation Method 1
a unique polymeric material that mimics metallic appearance and withstands sterilization
Implementation Method 2
followed by spin-welding and machining to eliminate flash and undesirable molding characteristics
Data Source
AI summary
The invention provides an endoscopic video camera having a polymeric knob assembly, wherein the polymeric material used for manufacturing the knob assembly includes polyphenylsulfone resin, titanium dioxide, tin oxide, and colored metallic additives, is capable of withstanding sterilization, and has a metallic cosmetic appearance. The invention also provides methods of manufacturing the knob assembly by plastic injection molding processes, wherein undesirable molding characteristics are concentrated on portions of the knob assembly that are removed by secondary machining or post machining.