Temperature-Controlled Casting Mould for Pore-Free Bone Cement Spacers
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Solution Overview
Problem
Current methods for producing spacers from polymethylmethacrylate (PMMA) bone cement using rubber-elastic casting moulds result in pore-like depressions and surface defects, which can lead to increased abrasion and inflammatory processes, and are not suitable for large-scale industrial production due to mould wear and high production costs.
Innovation Solution
A method involving temperature-controlled casting moulds made of non-elastic materials like stainless steel or polyethylene, where the cement dough is cured at a lower temperature than the mould, ensuring directional curing and reducing polymerisation shrinkage, thereby preventing surface defects and allowing for mass production of pore-free spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If rubber-elastic casting moulds are used to produce spacers from PMMA bone cement, then the production process is simple and flexible, but pore-like depressions and surface defects occur on the spacer surface
Solution Approach 1:
The invention changes the temperature parameter of the casting mould, heating it to between 40°C and 65°C before inserting the cement dough. This temperature parameter change prevents pore formation by controlling the polymerisation process, thereby improving surface quality while maintaining ease of manufacture
Solution Approach 2:
The invention uses a composite approach by combining rubber-elastic mould material with temperature control functionality. The mould becomes a temperature-controlled casting system that integrates both flexibility and precise thermal management to eliminate surface defects
2Adaptability or versatility
If rubber-elastic casting moulds are used for spacer production, then the process is flexible, but the moulds are sensitive to wear and tear and not suitable for large-scale production
Solution Approach 1:
The invention changes the material parameter of the casting mould from conventional rubber-elastic material to temperature-resistant materials such as polyethylene or stainless steel. This material substitution enables the moulds to withstand wear and tear, making them suitable for large-scale industrial production while maintaining production flexibility
Solution Approach 2:
The invention utilizes thermal expansion principles by heating the mould to specific temperatures (40°C-65°C) to control the polymerisation process. The temperature-resistant materials can withstand this thermal treatment without degradation, enabling both flexibility and durability for mass production
3Device complexity
If cement dough is cured at room temperature in conventional moulds, then the process is simple, but polymerisation shrinkage causes surface defects and pores
Solution Approach 1:
The invention changes the temperature parameter from room temperature to elevated temperatures (40°C-65°C) during curing. This parameter change controls the polymerisation rate and reduces shrinkage effects, eliminating pores and surface defects while maintaining process simplicity through straightforward heating
Solution Approach 2:
The invention applies preliminary heating to the mould before inserting the cement dough, establishing optimal curing conditions in advance. This preliminary action ensures that the polymerisation process occurs under controlled thermal conditions from the beginning, preventing pore formation without complex additional steps
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 produces spacers with smooth, pore-free surfaces, enhancing mechanical stability and reducing the risk of inflammatory processes, while enabling industrial-scale production using durable, cost-effective moulds.
Implementation Method 1
A) controlling the temperature of a casting mould to a first temperature
Implementation Method 2
allowing the cement dough to cure in the casting mould to form a spacer
Data Source
AI summary
The invention relates to a method for producing spacers from a bone cement comprising the following chronological steps:A) controlling the temperature of a casting mold to a first temperature;B) filling a cement dough, which has a temperature that is lower than the temperature of the temperature-controlled casting mold, into the temperature-controlled casting mold;C) allowing the cement dough to cure in the casting mold to form a spacer; andD) separating the casting mold from the spacer after the spacer is cured.The invention also relates to a device for producing spacers from a bone cement through said method comprising a casting mold and a temperature control facility for controlling the temperature of the casting mold, whereby at least 80% of the inner surface of the casting mold comprises a negative image of the spacer surface to be produced.