Polyamide Powder Composition for Stable Laser Sintering Reuse
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing polyamide powders used in 3D printing face challenges with increased molecular weight and viscosity during recycling, leading to difficult coalescence and reduced mechanical properties, requiring modifications to the sintering device and resulting in inconsistent object quality.
Innovation Solution
Incorporating a chain limiter, such as monoacids, dicarboxylic acids, or diamines, into the polyamide powder to control and stabilize viscosity and melting temperature, allowing for repeated use without altering the sintering device settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If polyamide powder is recycled multiple times in laser sintering, then powder reuse efficiency is improved, but viscosity and molecular weight increase leading to poor coalescence and reduced mechanical properties
Solution Approach 1:
The patent introduces chain limiters (monofunctional or bifunctional compounds) that chemically modify the polyamide chains to control molecular weight growth. These additives change the chemical parameters of the powder composition to prevent excessive viscosity increase during recycling, allowing maintenance of reliable mechanical properties across multiple printing cycles without altering the sintering process parameters
Solution Approach 2:
The patent creates a composite powder system by combining polyamide with chain limiter additives (such as carboxylic acids, amines, or their salts). This composite formulation leverages the chain-limiting effect of the additives to cap molecular weight growth, enabling both high powder reuse efficiency and consistent mechanical performance throughout the recycling process
2Ease of manufacture
If radiation power is increased to compensate for powder viscosity increase during recycling, then coalescence is improved, but energy consumption increases and object quality becomes inconsistent
Solution Approach 1:
The patent modifies the material parameters by incorporating chain limiters that control molecular weight and viscosity growth. This chemical parameter change ensures that the powder maintains appropriate flow and coalescence characteristics throughout recycling, eliminating the need to progressively increase radiation power and thereby maintaining consistent energy consumption and object quality across multiple prints
3Reliability
If metal soaps are added to polyamide powder to limit molecular weight increase, then viscosity control is improved, but metal salt derivatives leach out contacting solvents restricting application areas
Solution Approach 1:
The patent replaces metal soap additives with non-metallic chain limiters (carboxylic acids, amines, or their organic salts). This substitution maintains the desired viscosity control and molecular weight limitation functions while eliminating the harmful leaching issue, as the organic chain limiters do not produce metal salt derivatives that would contaminate the printed objects when exposed to solvents
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 chain limiter enables reproducible mechanical properties and easy recycling of polyamide powder, maintaining object quality across multiple cycles without the need for device adjustments.
Implementation Method 1
the addition of at least one chain limiter in the solid or liquid state, in particular a monoacid, a dicarboxylic acid, a monoamine or a diamine, to a polyamide powder makes it possible to control, in particular to lower, stabilize or eliminate, the increase in the viscosity and the melting temperature of the non-agglomerated polyamide powder
Implementation Method 2
The agglomeration of powders by melting (or 'sintering') is brought about by radiation, such as for example a laser beam (also known as laser sintering), infrared radiation, UV radiation, LED-type radiation or any source of electromagnetic radiation which makes it possible to melt the powder layer by layer
Implementation Method 3
The laser makes it possible to fuse powder particles at various points in the layer which crystallize slowly after the passage of the laser according to a geometry corresponding to the object
Implementation Method 4
The laser makes it possible to fuse powder particles at various points in the layer which crystallize slowly after the passage of the laser according to a geometry corresponding to the object
Data Source
AI summary
A polyamide powder for use in a process of powder agglomeration by sintering, including at least one chain limiting agent. A process for preparing a powder including at least one chain limiting agent, wherein the chain limiter is mixed with the polyamide powder, and if need be at least one thioether antioxidant, by dry blending.