Low-temperature nylon powder material for selective laser sintering and preparation method thereof

Abstract

The invention relates to the technical field of polymer composites and particularly relates to a low-temperature nylon powder material for selective laser sintering. The low-temperature nylon powder material mainly comprises nylon 12 particles, dodecanedioic acid, double amino-terminated polyethylene glycol, deuterated trifluoroacetic acid, an antioxidant, a solvent, a nucleating agent, a plasticizer and a silane coupling agent. The low-temperature nylon powder material is prepared by the following steps: uniformly mixing the dodecanedioic acid and nylon 12 particles and putting into a reaction kettle; adding the double amino-terminated polyethylene glycol and deuterated trifluoroacetic acid into the reaction kettle; heating and starting stirring to obtain a product; putting the product together with the antioxidant, solvent, nucleating agent, plasticizer and silane coupling agent into the reaction kettle, and closing the kettle with a cover; vacuumizing the reaction kettle and introducing nitrogen displacement for protection; starting stirring and reducing the temperature of the kettle body to room temperature; taking out the materials, drying and performing ball milling; and drying the powder to obtain powder with good sphericity and fluidity. The low-temperature nylon powder material provided by the invention has the characteristics of low preheating temperature, wide preheating window, good aging resistance and adaptability to table boards of various specifications.

Description

technical field [0001] The invention relates to the technical field of polymer composite materials, in particular to a low-temperature nylon powder material for selective laser sintering and a preparation method thereof. Background technique [0002] Additive manufacturing (commonly known as 3D printing, also known as rapid prototyping & manufacturing) technology is a new advanced manufacturing technology involving computer, control, machinery, materials and other sciences. It breaks the traditional process of material deformation molding and removal molding, and adopts the additive molding method of layer-by-layer manufacturing and superimposition, which can theoretically manufacture any complex three-dimensional solid parts. [0003] Selective Laser Sintering (SLS) technology is a current mainstream additive manufacturing technology. Polymer powder material is the earliest and most widely used SLS material. It melts or softens during laser sintering, and crystallizes and ...

AI Technical Summary

Problems solved by technology

This not only greatly increases the cost of SLS equipment, but is also very difficult in terms of technical implementation

The direct laser sintering nylon equipment launched by 3D Systems and EOS all have small worktables, and laser sintering of nylon on large worktable equipment is still not possible. However, the SLS equipment sold by the Rapid Manufacturing Center of Huazhong University of Science and Technology in recent years is all large worktables. SLS equipment

[0008](3) Nylon powder is prone to aging at high temperature, which leads to a sharp decline in the mechanical properties of SLS parts and deterioration of laser sintering performance

The price of nylon powder is extremely high, and a large amount of powder that cannot be reused is a serious waste. It is difficult for domestic enterprises to accept such high operating costs, which makes SLS technology lose its competitive advantage in directly preparing plastic functional parts

At present, the SLS equipment developed in China is operated in an air atmosphere, so it cannot meet the requirements of laser sintering nylon powder

[0009] (4) The preheating time of nylon powder before forming is long, and the cooling procedure after forming is also very strict, which makes the forming cycle longer and reduces the utilization rate of SLS equipment

[0010] (5) Since the preheating temperature is close to the melting point of nylon, the crystallization enthalpy of nylon is very large, and the cumulative effect of heat during forming is very obvious, and the powder around the sintered body is easily formed. For melting or agglomeration, the excess heat must be taken away by gas, and the laser power and preheating temperature must change with the change of the shape and structure of the sintering section. The operation is very complicated and cannot be automated, so it is difficult to promote it to production.

[0018] cannot meet the above requirements

Based on the above reasons, it is still very difficult to realize the commercialization of existing nylon powder on domestic equipment

Images