Microstructured Calcium Carbonate Composite Powder for Selective Laser Sintering
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Solution Overview
Problem
Existing calcium carbonate-containing composite powders for selective laser sintering exhibit poor flowability, leading to inadequate surface quality, component density, and dimensional stability, with challenges in biocompatibility and thermal degradation, particularly in medical applications where solvent-free and efficient manufacturing processes are crucial.
Innovation Solution
A composite powder with microstructured particles is developed by combining large polymer particles with spherical precipitated calcium carbonate particles, where the calcium carbonate particles are produced by carbonating a calcium hydroxide suspension with aminotrialkylenephosphonic acid, enhancing flowability and allowing for improved surface quality, component density, and dimensional stability during laser sintering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional composite particles are used, then calcium carbonate content is achieved, but flowability deteriorates
Solution Approach 1:
The patent applies spheroidality by using spherical calcium carbonate particles instead of conventional irregularly shaped particles. The spherical geometry improves flowability while maintaining calcium carbonate content, directly resolving the technical contradiction between quantity of substance and ease of operation.
2Productivity
If ground composite particles are sintered, then components are produced, but surface quality deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-forming spherical particles with embedded calcium carbonate before the sintering process. This preliminary structuring ensures that the particles maintain their shape and distribution during sintering, resulting in improved surface quality while maintaining manufacturing efficiency.
3Productivity
If ground composite particles are sintered, then components are produced, but component density deteriorates
Solution Approach 1:
The spherical particles are pre-structured with calcium carbonate embedded within them before sintering. This preliminary arrangement ensures uniform distribution and optimal packing during the sintering process, achieving high component density without sacrificing manufacturing efficiency.
4Ease of operation
If flow aids are added to improve flowability, then flowability improves, but biocompatibility deteriorates
Solution Approach 1:
The patent extracts and eliminates flow aids from the formulation by using spherical calcium carbonate particles that inherently provide good flowability. This removal of harmful additives maintains biocompatibility while still achieving the desired flow properties.
5Ease of manufacture
If conventional materials are used for laser sintering, then manufacturing is possible, but shrinkage behavior deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the particle morphology to spherical shape and optimizing the size distribution of calcium carbonate particles. These parameter changes result in more uniform heating and melting behavior during laser sintering, improving shrinkage behavior and dimensional stability while maintaining ease of manufacture.
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 composite powder demonstrates improved flowability, surface quality, component density, and dimensional stability, with reduced thermal degradation and enhanced biocompatibility, enabling the production of high-quality, biodegradable implants with controlled resorption kinetics and mechanical properties suitable for medical applications.
Implementation Method 1
carbonating a calcium hydroxide suspension with aminotrialkylenephosphonic acid
Implementation Method 2
selective laser sintering
Implementation Method 3
selective laser sintering (SLM) process
Data Source
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Figure 3a
AI summary
The invention relates to a composite powder having microstructured particles, obtainable by a method wherein large particles are connected to small particles, wherein the large particles have an average particle diameter in the range from 0.1 μm to 10 mm, the large particles comprise at least one polymer, the small particles are arranged on the surface of the large particles and/or inhomogeneously distributed within the large particles, the small particles comprise spherical precipitated calcium carbonate particles having an average diameter in the range from 0.05 μm to 50.0 μm, wherein the spherical calcium carbonate particles are obtainable by a method wherein a. a calcium hydroxide suspension is provided, b. carbon dioxide or a gas mixture containing carbon dioxide is introduced into the suspension from step a. and c. occurring calcium carbonate particles are separated, wherein 0.3 wt% to 0.7 wt% of at least one aminotrialkylene phosphonic acid is furthermore added. Preferred application areas of the composite powder comprise the use thereof as an additive, in particular as a polymer additive, as an additive material or starting material for compounding, for the production of components, for applications in medical technology and/or in microtechnology and/or for the production of foamed objects. The invention thus further relates to components which are obtainable by selective laser sintering of a composition, comprising a composite powder according to the invention, except implants for applications in the fields of neurosurgery, oral surgery, maxillofacial surgery, neck surgery, nasal and ear surgery, and hand, foot, thoracic, rib, and shoulder surgery. The invention further relates to the spherical calcium carbonate particles that can be advantageously used for producing the composite particles according to the invention, and to the use thereof.