Porous Prosthesis Surface Connection With Intermediate Welding Layer
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Solution Overview
Problem
Current methods for connecting porous surface structures to substrates in medical devices, such as joint prostheses, face challenges in maintaining mechanical strength while ensuring effective bone ingrowth, as existing welding techniques like laser welding and diffusion bonding either weaken the substrate or cause thermal damage.
Innovation Solution
A connected structure comprising a porous surface structure and a substrate with an intermediate structure, where the composite body has varying stiffness regions to optimize resistance welding, reducing substrate stiffness and preventing surface damage through the use of conductive materials and support posts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser welding is used to connect porous structure and substrate, then welding efficiency is improved, but the laser energy directly breaks the scaffolds and destroys the porous structure
Solution Approach 1:
A solid intermediate structure is introduced between the porous surface structure and the substrate. This intermediate layer acts as a mediator that receives laser welding heat from the substrate without transmitting it directly to the porous scaffolds, thereby protecting the porous structure from thermal damage while maintaining effective welding connection.
Solution Approach 2:
The connection structure is divided into three distinct segments: the porous surface structure, the solid intermediate structure, and the substrate. This segmentation allows each component to perform its specific function - the porous structure for bone ingrowth, the intermediate for structural support and welding protection, and the substrate for mechanical strength.
2Device complexity
If resistance welding is used directly on highly porous structure, then welding process is simplified, but welding efficiency is low and excessive heat causes thermal damage to porous structure surface
Solution Approach 1:
The solid intermediate structure acts as a thermal buffer during resistance welding. It receives the welding heat and protects the porous structure surface from excessive thermal damage, while still allowing the welding process to proceed with relative simplicity.
3Adaptability or versatility
If porous structure with high porosity (>50%) is used, then bone ingrowth capability is improved, but the interconnected scaffolds are weak and cannot achieve effective welding
Solution Approach 1:
The structure is segmented into two functional zones: the porous surface structure with high porosity for bone ingrowth, and the solid intermediate structure for mechanical strength and welding. This segmentation allows each zone to be optimized for its specific function without compromise.
Solution Approach 2:
The invention creates a composite structure combining porous material (for biological function) with solid material (for mechanical function). This composite approach allows the system to simultaneously achieve high bone ingrowth capability and sufficient structural strength for welding and load-bearing.
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 enhances welding efficiency and strength between the porous surface and substrate, maintaining mechanical integrity while promoting bone ingrowth and reducing manufacturing costs and time.
Implementation Method 1
an effective bonding is formed through the resistance heat generated by the electric current flowing through the physical contact between the two workpieces
Implementation Method 2
the intermediate structure base plate... While maintaining sufficient structural strength of the connected structure of the composite body and the substrate
Data Source
AI summary
The present invention discloses a connected structure of a porous surface structure and a substrate, a method for preparing the same, and a prosthesis of the same. The connected structure consists of a pre-connected or integrally formed composite body of a porous surface structure and an intermediate; and a substrate, which is connected to said intermediate to achieve the connection of said composite body to the said substrate; the composite body comprising a first composite region corresponding to a first stiffness; a remaining composite region in the composite body other than the first composite region, which at least contains a second composite region corresponding to a second stiffness; and the first stiffness is less than the second stiffness. The present invention achieves a fastened connection between the composite and the substrate and largely maintains the mechanical properties of the substrate; and it provides a prosthesis with excellent bone ingrowth properties and that the strength of the substrate is not substantially affected.