Magnesium Alloy Medical Implant Manufacturing Process
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Solution Overview
Problem
Bioresorbable magnesium alloy implants used in medicine often lack sufficient mechanical strength and resistance to corrosion, requiring expensive additives that are difficult to break down in the body, and existing manufacturing processes for these alloys are not well-documented, especially for highly pyrophoric magnesium alloys.
Innovation Solution
A method involving melting, atomizing in a protective gas atmosphere, cooling, shaping by compaction, and extruding magnesium alloy powder to produce a moulded article with improved mechanical strength and reduced corrosion, using specific temperature and pressure conditions to achieve a narrow particle size distribution and uniformity, and optionally coating with calcium phosphates to control corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If magnesium alloy implants are made with high magnesium content (≥80% by weight) to ensure bioresorbability, then the implants can be broken down by the body's decomposition mechanisms, but the mechanical strength and resistance to corrosion fail to reach required performance levels
Solution Approach 1:
The patent optimizes the alloy composition parameters by precisely controlling the content of alloying elements (Ca: 1-10 wt%, Si: 1-10 wt%, Mn: 1-5 wt%, MgO: 1-10 wt%) to achieve the desired balance between bioresorbability and mechanical strength. This parameter optimization allows the implant to maintain sufficient strength while remaining bioresorbable.
Solution Approach 2:
The patent creates a composite magnesium alloy system by combining magnesium with multiple alloying elements (Ca, Si, Mn, MgO) that work synergistically. This composite approach enhances the mechanical properties and corrosion resistance of the base magnesium alloy while maintaining its bioresorbable character, resolving the contradiction between strength and degradability.
2Strength
If alloy additives such as neodymium, yttrium, zirconium, zinc, calcium, and other rare earth elements are used to control strength and corrosion rate, then the mechanical strength and resistance to corrosion improve, but the implants become expensive and some additives cannot be broken down without difficulty in the human body
Solution Approach 1:
The patent replaces expensive rare earth elements with more cost-effective and biocompatible alloying elements. By optimizing the composition parameters (Ca: 1-10 wt%, Si: 1-10 wt%, Mn: 1-5 wt%, MgO: 1-10 wt%), the patent achieves the required mechanical strength and corrosion resistance without using expensive additives that are difficult to break down in the human body.
Solution Approach 2:
The patent uses inexpensive alloying elements (Ca, Si, Mn, MgO) that are readily available and biocompatible, replacing expensive rare earth elements. These cheaper additives provide the necessary mechanical enhancement while being fully bioresorbable, reducing both cost and biodegradation issues.
3Ease of manufacture
If conventional casting or mechanical forming processes are used to mould magnesium alloy implants, then the manufacturing process is simple, but the mechanical strength and resistance to corrosion often fail to reach required performance levels
Solution Approach 1:
The patent optimizes the alloy composition parameters (Ca: 1-10 wt%, Si: 1-10 wt%, Mn: 1-5 wt%, MgO: 1-10 wt%) to inherently improve the mechanical strength and corrosion resistance of the magnesium alloy, allowing conventional manufacturing processes to produce implants that meet performance requirements without complex additional treatments.
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 method results in magnesium alloy implants with enhanced mechanical strength and reduced corrosion rates, maintaining strength over time and ensuring bioresorbability, thus eliminating the need for surgical removal.
Implementation Method 1
a) melting the magnesium alloy to obtain an alloy melt
Implementation Method 2
b) atomising the molten alloy in a protective gas atmosphere and at the same time cooling the atomised molten alloy to below the solidification point thereof to obtain an alloy powder
Implementation Method 3
cooling the atomised molten alloy to below the solidification point
Data Source
AI summary
A method for producing a medical implant, such as a bone screw, a bone nail, a bone pin, a plate, a suture anchor, etc. for fastening soft parts, such as tendons, muscles, and ligaments, to a bone, or in the form of an endoprosthesis or at least a part thereof, from a magnesium alloy having a magnesium fraction of at least 80 wt %, in particular of at least 90 wt %, including the following steps: a) melting the magnesium alloy to obtain an alloy melt, b) atomizing the alloy melt under a protective-gas atmosphere and cooling the atomized alloy melt to below the solidification point thereof in order to obtain an alloy powder, c) shaping the alloy powder by pressing to obtain an alloy green body, d) extruding the alloy green body to obtain a magnesium alloy molded part, and e) producing the medical implant from the magnesium alloy molded part.