Polyamide MXD6 Sinter Powder for Selective Laser Sintering
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Solution Overview
Problem
Polyamide MXD6 is not suitable for three-dimensional printing processes like selective laser sintering due to its high melting temperature and inconsistent crystallization, leading to reduced sintering windows and component distortion.
Innovation Solution
A sinter powder comprising a blend of polyamide MXD6, semicrystalline polyamide, optional additives, and optional reinforcers, which improves the mechanical properties and processability of the powder for selective laser sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If polyamide MXD6 is used for selective laser sintering, then higher strength and stiffness are achieved, but the high melting temperature and inconsistent crystallization lead to reduced sintering window and component distortion
Solution Approach 1:
The patent uses a composite material system consisting of polyamide MXD6 blended with polyamide 6 and polyamide 66 in specific ratios (30-70 wt% MXD6, 10-40 wt% PA6, 10-40 wt% PA66). This composite approach combines the high strength and stiffness of MXD6 with the lower melting temperature and more consistent crystallization behavior of PA6 and PA66, thereby maintaining mechanical properties while improving sintering window and reducing distortion
Solution Approach 2:
The patent modifies the compositional parameters of the polymer blend to optimize sintering behavior. By adjusting the ratios of MXD6, PA6, and PA66, the melting temperature range and crystallization characteristics are tuned to achieve a wider sintering window. The presence of PA6 and PA66 lowers the overall melting point and provides more consistent crystallization, preventing distortion while retaining the mechanical advantages of MXD6
2Reliability
If polyamide MXD6 is used directly for SLS, then excellent barrier properties and temperature-independent mechanical properties are achieved, but the high melting temperature requires high build temperatures and the broad crystallization peak reduces sintering window
Solution Approach 1:
The patent creates a composite powder blend where polyamide MXD6 is combined with polyamide 6 and polyamide 66. This composite structure allows the system to maintain the excellent barrier properties and temperature-independent mechanical properties of MXD6 while the PA6 and PA66 components lower the melting temperature and narrow the crystallization peak, enabling processing at reduced build temperatures with a wider sintering window
3Ease of manufacture
If polyamide MXD6 is processed via cryo-grinding to produce sinter powder, then powder form is achieved, but the crystallization temperature is increased and crystallization consistency is reduced
Solution Approach 1:
The patent combines cryo-grinded polyamide MXD6 powder with polyamide 6 and polyamide 66 powders to create a composite sinter powder. The PA6 and PA66 components act as crystallization modifiers that compensate for the broadening and temperature increase caused by cryo-grinding of MXD6. This composite approach maintains the powder form necessary for SLS while restoring consistent crystallization behavior at appropriate temperatures
Solution Approach 2:
The polyamide 6 and polyamide 66 components serve as intermediary substances that mediate the crystallization process. They provide nucleation sites and facilitate more consistent crystallization of the MXD6 particles that have been subjected to cryo-grinding, thereby compensating for the adverse effects of the grinding process on crystallization temperature and consistency
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 sinter powder exhibits improved elongation at break and yield, consistent crystallization, and reduced crystallization temperature, resulting in enhanced mechanical properties and processing efficiency for three-dimensional printed components.
Implementation Method 1
selective exposing of a polymer powder in a chamber with a laser beam. The powder melts; the molten particles coalesce and resolidify.
Implementation Method 2
exposing the layer of sinter powder (SP) provided in step i) with a laser beam
Implementation Method 3
the crystallization of polyamide MXD6 is rather inconsistent (broad crystallization peak) and the crystallization temperature is increased
Data Source
AI summary
The present invention relates to a sinter powder (SP) comprising at least one polyamide MXD6 (A), at least one semicrystalline polyamide (B), optionally at least one additive (C) and optionally at least one reinforcer (D). The present invention further relates to a method of producing a shaped body using the inventive sinter powder (SP), to a shaped body obtained by this method and to the use of the inventive sinter powder (SP) in a sintering method. In addition, the present invention relates to a method of producing the sinter powder (SP) and to the use of at least one semicrystalline polyamide (B) in a sinter powder (SP) comprising at least one polyamide MXD6 (A) for improving the mechanical properties of shaped bodies made from said sinter powder (SP).