Poly(aryl–ether–ketone) (PAEK) powder suitable for multiple use in sintering methods

Abstract

The invention relates to a poly(aryl-ether-ketone) (PAEK) powder, for use in a method for building objects layer-by-layer by electromagnetic radiation-generated sintering, said powder being characterized in that it is obtained from a thermal pretreatment at a temperature comprised between 260° C. and 290° C., preferably between 280° C. and 290° C., and in that it has a melting temperature which is stable, at the build temperature, and below or equal to 330° C., preferably below or equal to 320° C., and more preferably below or equal to 310° C.

Description

TECHNICAL FIELD[0001]The invention relates to powders particularly intended for use in methods for additive, layer-by-layer fabrication of three-dimensional objects by electromagnetic radiation-generated sintering of said powder. In particular, it relates to poly(aryl-ether-ketone) (PAEK) powders and the recyclability thereof in such methods.[0002]Said electromagnetic radiation can be a laser beam (in the case of laser sintering), infrared radiation, UV radiation, or any other source of radiation. The term “sintering” in the present description includes all these methods, regardless of the type of radiation. Although in the following text reference is most often made to the laser sintering method, what is written for laser sintering is of course valid for the other sintering methods.PRIOR ART[0003]Poly(aryl-ether-ketone)s are well-known high-performance engineering polymers. They are used for applications which are restrictive in terms of temperature and / or of mechanical or even che...

AI Technical Summary

Benefits of technology

The invention is about a new type of powder called poly(aryl-ether-ketone) (PAEK) that can be used to build three-dimensional objects using a laser sintering method. This powder has several advantages, including that it can be used multiple times without losing its effectiveness, and that it can be easily sintered to create objects with good strength and flexibility. The invention also includes a method for using this powder to build objects layer-by-layer using electromagnetic radiation. The resulting three-dimensional article has the same mechanical properties regardless of the number of times the powder is used.

Problems solved by technology

However, during a sintering run, the surrounding powder—i.e., the powder not affected by the electromagnetic radiation—remains at this temperature for several hours or even several tens of hours, depending on the complexity of the part to be built, which can lead to a change in the structure of the polymer constituting the powder, thereby increasing its molecular weight, for example.

This increase in molecular weight leads to an increase in viscosity which impedes coalescence between the powder particles during successive runs.

Due to this structural change, it becomes difficult or even impossible to recycle the powder because either it becomes impossible to sinter the powder or the mechanical properties of the three-dimensional part, obtained by laser sintering such a recycled powder, become diminished and inadequate owing to the presence of porosities in the sintered parts.

However, from the first run, the PEEK powder undergoes such thermal degradation that it is not possible to reuse it for the second run.

Consequently, the fabrication of three-dimensional objects by sintering of this powder is much too expensive and cannot be envisaged on an industrial scale.

Indeed, this document discloses that the PEKK powder used is not temperature-stable and that its melting temperature increases after its first use in a sintering method.

The fact of having to change these sintering parameters with each run makes industrial production slower and more difficult.

Moreover, it appears difficult to mix non-recycled powder with recycled powder, because the build parameters are then complicated to adjust.

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