HK1139361B

HK1139361B - A method for influencing specific mechanical properties of three-dimensional objects manufactured from a powder

Info

Publication number: HK1139361B
Application number: HK10105410.9A
Authority: HK
Inventors: M‧罗伊特勒; A‧普菲策尔; F‧米勒; A‧伍德; B‧维尔森; H‧桑德纳
Original assignee: Eos有限公司电镀光纤系统
Priority date: 2008-05-20
Filing date: 2010-06-02
Publication date: 2017-03-10

Description

Method for influencing specific mechanical properties of three-dimensional objects produced from powder

Technical Field

The invention relates to a method for producing three-dimensional objects from a powder by means of selective sintering using electromagnetic radiation of the powder, wherein the powder comprises at least one polymer material and wherein the three-dimensional objects produced have a crystallinity which is advantageously reduced compared to conventional selective sintering using electromagnetic radiation. Furthermore, the invention relates to a three-dimensional object obtained by the method, a device for use in the method, and the use of a preselected polymer powder in the method.

Background

As is known from DE4410046, a method for producing three-dimensional objects by selective sintering using electromagnetic radiation can be carried out in a layered manner with an electromagnetic radiation source. In such a method, three-dimensional objects are produced in a laminar manner by applying layers of powder and bonding the layers to one another by selective solidification of the powder at positions in the layers corresponding to the cross-section of the object.

Fig. 1 shows an example of a laser sintering apparatus with which a method for producing three-dimensional objects in a layered manner can be carried out. As can be clearly seen in fig. 1, the device comprises a container 1. This container is open at the top and is bounded at the bottom by a support 4 for holding the object 3 to be formed. The work plane 6 is defined by the upper edge 2 of the container (or by the side walls of the container). The object is located on the top side of the support 4 and is formed from a plurality of layers of construction material in powder form that can be solidified by electromagnetic radiation, wherein the layers are parallel to the top side of the support 4. The support can be movable in the vertical direction, i.e. parallel to the side walls of the container 1, via a height adjustment device. The position of the support 4 relative to the work plane 6 can thus be adjusted.

Above the container 1 or more precisely above the work plane 6, an application device 10 is provided to apply the powder material 11 to be cured onto the support surface 5 or onto a previously cured layer. Also, a radiation device in the form of a laser 7 emitting a directed beam 8 is arranged above the work plane 6. The light beam 8 is directed as a deflected light beam 8' towards the work plane 6 by a deflection device 9, such as a rotating mirror. The control unit 40 allows to control the support 4, the application device 10 and the deflection device 9. The components 1-6, 10, and 11 are located within the frame 100.

When manufacturing the three-dimensional object 3, the powder material 11 is applied in layers to the support 4 or to previously solidified layers and solidified with the laser beam 8' on the respective powder layer in a position corresponding to the object. After each selective curing of the coating, the support reduces the thickness of the subsequently applied powder layer.

Many improvements in methods and apparatus for manufacturing three-dimensional objects by selective sintering using electromagnetic radiation have been and can be used compared to the systems described above. For example, instead of using a laser and/or a beam, other systems that selectively output electromagnetic radiation can be used, such as mask exposure systems and the like.

However, in previous methods of selectively sintering polymer powders by electromagnetic radiation, the mechanical properties of the manufactured object were not sufficiently noticed.

It is therefore an object of the present invention to provide an improvement of the method for manufacturing three-dimensional objects by selective sintering of polymer powders using electromagnetic radiation, which results in improved mechanical properties of the manufactured objects.

Disclosure of Invention

It has surprisingly been found according to the present invention that when the three-dimensional object produced is observed to have a specific range of crystallinity, a significant improvement in certain very advantageous mechanical properties is obtained, including but not limited to high stiffness, high compressive strength, high impact strength, high maximum tensile and flexural strength as well as high elongation at break and high heat deflection temperature, while on the other hand the opposite or mutually compromised properties such as good chemical resistance and low post-shrinkage due to post-crystallization are well balanced. It has furthermore surprisingly been found that particular process conditions, in particular with regard to the cooling time after sintering, and also particular selection criteria relating to the preselected polymer material, either alone or in combination, contribute to a significant enhancement of the above-mentioned mechanical properties and balance of properties. In addition, a significantly improved combination of both controlled crystallinity and low porosity in the fabricated three-dimensional object can be achieved, which contributes to further improvements in the above properties. The advantages of the invention are particularly achieved when polyaryletherketone polymers or polyaryletherketone copolymers or when polyamide polymers or polyamide copolymers are suitably used as the polymeric material of the polymer powder. Furthermore, the advantages of the present invention may also be applied to composite materials, wherein the crystallinity value is related to the polymer matrix of the composite material. Such composites comprise, in addition to a matrix comprising the respective polymer, copolymer or blend, one or more fillers and/or additives.

As a preferred alternative to conventional polymer processing techniques involving pressure processing of polymers, like for example injection molding, the process according to the invention can be carried out in a layer-wise manner in an additive process (additive-wise) in which successive layers of the object formed from the curable powder material are required to be subsequently cured by electromagnetic radiation at locations corresponding to the cross-section of the object.

The various aspects, advantageous features and preferred embodiments of the invention, summarized in the following items, are-separately or in combination-used for achieving the object of the invention:

(1) a method of manufacturing a three-dimensional object from a powder by selective sintering using electromagnetic radiation of the powder, wherein the powder comprises a preselected polymer or copolymer and is selectively sintered such that the manufactured three-dimensional object has a final crystallinity in a range in which the balance of the overall mechanical properties of young's modulus, tensile strength and elongation at break is improved.

The Young's modulus of the polymer or copolymer is preferably at least 500MPa, more preferably at least 1000MPa and especially at least 2000MPa, the tensile strength is preferably at least 20MPa, more preferably at least 30MPa and especially at least 40MPa and the elongation at break is preferably at least 1%, more preferably at least 2%, even more preferably at least 5%, and especially at least 20%.

To provide more specific values, for example, for polyaryletherketone polymers and polyaryletherketone copolymers, the young's modulus is preferably at least 3000MPa, more preferably at least 3500MPa and especially at least 4000MPa, the tensile strength is preferably at least 50MPa, more preferably at least 70MPa and especially at least 90MPa and the elongation at break is preferably at least 1.5%, more preferably at least 2%, even more preferably at least 3%, and especially at least 5%, and for polyamide polymers and polyamide copolymers, the young's modulus is preferably at least 1000MPa, more preferably at least 1500MPa, even more preferably at least 2500MPa, the tensile strength is preferably at least 35MPa, more preferably at least 45MPa and especially at least 70MPa and the elongation at break is preferably at least 5%, more preferably at least 20%, even more preferably at least 40% and especially at least 60%.

(2) A method of manufacturing a three-dimensional object from a powder by selective sintering using electromagnetic radiation of the powder, wherein the powder comprises a preselected polymer or copolymer and is selectively sintered such that the manufactured three-dimensional object has a final crystallinity of 80% or less, preferably 50% or less, especially 5 to 70%, more preferably 15 to 50% and especially 15 to 35%, alone or in combination with the method of (1) above.

(3) The method according to (1) or (2), wherein layers of the object to be formed from the curable powder material are successively cured at positions corresponding to a cross section of the object.

(4) A method according to any one of the preceding items, in which method the electromagnetic radiation is provided by a laser.

(5) A method according to any one of the preceding claims, comprising a predetermined and/or controlled cooling step after completion of the sintering step.

(6) A method according to any of the preceding items, wherein the three-dimensional object produced has a porosity of less than 10%, preferably less than 5%, more preferably less than 3% and most preferably less than 2%.

(7) The method according to any one of the preceding items, wherein the powder comprising the polymer or copolymer has a melting point Tm in the range of 100 ℃ to 450 ℃, preferably 150 ℃ to 400 ℃ and more preferably 250 ℃ to 400 ℃.

(8) Process according to any one of the preceding items, wherein the polymer or copolymer has a molecular weight Mn of at least 10,000, preferably 20,000-200,000, more preferably 20,000-100,000 or a Mw of at least 20,000, preferably 30,000-500,000, more preferably 30,000-200,000.

(9) The process according to any one of the preceding items, wherein the polymer or copolymer has a degree of polymerization of preferably 10 to 10,000, more preferably 20 to 5,000 and especially 50 to 1,000.

(10) The method according to any one of the preceding items, wherein the polymer or copolymer comprises at least one aromatic group in the backbone chain, preferably in at least one of the repeating units of the backbone chain.

(11) The method according to item (10), wherein the aromatic groups each independently represent an unsubstituted or substituted monocyclic or polycyclic aromatic hydrocarbon.

(12) The method according to item (10) or (11), wherein the aromatic groups are each independently selected from the group consisting of 1, 4-phenylene, 4, 4 '-biphenylene, 4, 4' -isopropylidenediphenylene, 4, 4 '-diphenylsulfone, 1, 4-, 1, 5-, and 2, 6-naphthylene, 4, 4' -triphenylene, and 2, 2-bis- (4-phenylene) -propane.

(13) The method according to items (10) to (12), wherein the aromatic group is substituted with one or more side chains.

(14) The method according to items (10) to (13), wherein the side chains are each independently selected from the group consisting of C1-C6 linear or branched or cyclic alkyl and alkoxy groups, and aryl groups.

(15) The process according to item (13) or (14), wherein the side chains are each independently selected from methyl, isopropyl, tert-butyl or phenyl.

(16) A method according to any one of the preceding items, wherein the end groups of the backbone chains of the polymer or copolymer are modified.

(17) A method according to any one of the preceding items, wherein a blend of at least two different polymers or copolymers is used.

(18) The process according to (17), wherein one component of the blend reduces the final crystallinity of the manufactured object.

(19) The method according to any of the preceding items, wherein the polymer or copolymer is selected from the group consisting of Polyamides (PA), Polyaryletherketones (PAEK), Polyarylethersulfones (PAES), polyesters, polyethers, polyolefins, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyphenylene oxide, polyimides and copolymers and blends comprising at least one of the foregoing polymers.

(20) A method according to any one of the preceding items, wherein the polymer or copolymer is selected from: polyamides, polyaryletherketones, and copolymers and blends comprising at least one of the foregoing polymers.

(21) A process according to any one of the preceding items, wherein the polymer or copolymer is a Polyaryletherketone (PAEK) selected from: polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherketone (PEK), Polyetheretherketoneketone (PEEKK) and Polyetherketoneetherketoneketone (PEKEKK) and Polyetheretherketone (PEEEK) and copolymers and blends comprising at least one of the foregoing polymers.

(22) The process according to any of the preceding items 1, wherein the polymer or copolymer is a Polyaryletherketone (PAEK) selected from PEEK, PEK, PEKEKK, and copolymers and blends comprising at least one of the foregoing polymers.

(23) The process according to any one of the preceding items, wherein the copolymer is a Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -copolymer.

(24) The method according to (23), wherein the ratio of the amount of sulfone groups to the amount of ketone groups in the PAEK/PAES copolymer is in the range of 50: 50 to 10: 90.

(25) The process according to (23) or (24), wherein the Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -copolymer is selected from Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -diblock copolymer or PAEK/PAES/PAEK-triblock copolymer, preferably selected from (PEK)/(PES) -diblock copolymer and PEK/PES/PEK-triblock copolymer.

(26) The process according to any one of (19) to (25), wherein the Polyaryletherketone (PAEK) polymer or copolymer has a molecular weight Mn of at least 9,000, preferably 10,000-100,000, more preferably 15,000-50,000 and most preferably 20,000-35,000 or a Mw of 20,000-500,000, preferably 40,000-200,000 and more preferably 50,000-125,000.

(27) The process according to any one of (20) to (26), wherein the Polyaryletherketone (PAEK) polymer or copolymer has a molecular weight in the range of 0.05 to 1.0kN s/m²Preferably 0.15-0.6kN s/m²And in particular 0.2-0.45kN s/m²A melt viscosity within the range of (a).

(28) The process according to (19), wherein the Polyaryletherketone (PAEK) polymer or copolymer has a degree of polymerization n of preferably 10 to 1,000, more preferably 20 to 500 and especially 40 to 250.

(29) The process according to any one of (19) to (28), wherein the polymer or copolymer is a Polyaryletherketone (PAEK) and wherein the three-dimensional object produced has a final crystallinity of 5 to 45%, preferably 10 to 40%, more preferably 15 to 35%, even more preferably 15 to 30% and most preferably 20 to 25%.

(30) The process according to any one of (19) to (29), wherein the polymer or copolymer is a Polyaryletherketone (PAEK) and wherein the three-dimensional object produced has at least 1.24g/cm³More preferably 1.26g/cm³And even more preferably 1.28g/cm³And most preferably > 1.30g/cm³The density of (c).

(31) The process according to (19), wherein the polymer or copolymer is a Polyamide (PA) and wherein the three-dimensional object produced has a final crystallinity of 10 to 50%, more preferably 15 to 40%, even more preferably 15 to 35% and most preferably 20 to 30%.

(32) The process according to (31), wherein the Polyamide (PA) polymer or copolymer has at least one recurring unit of skeleton chain, wherein the length of at least one fatty chain is preferably in C₄-C₁₈More preferably C₆-C₁₂And in particular C₁₀-C₁₂Within the range of (1).

(33) The method according to (32), wherein the polymer or copolymer is a Polyamide (PA) and wherein the three-dimensional object produced has at least 0.90g/cm³More preferably 0.95g/cm³And especially 1.00g/cm³The density of (c).

(34) A method according to any of the preceding items, comprising a step of cooling the object after completion of the object from a temperature 1-50 ℃, more preferably 1-30 ℃, even more preferably 1-20 ℃ and most preferably 1-10 ℃ below the Tm of the polymer or copolymer comprised by the powder to the Tg of the polymer or copolymer comprised by the powder at a cooling rate of 0.01-10 ℃, preferably 0.1-5 ℃, more preferably 1-5 ℃/min, wherein Tm is the melting temperature of the polymer or copolymer comprised by the powder and Tg is the glass transition temperature of the polymer or copolymer, respectively.

(35) Method for manufacturing a three-dimensional object from a powder by means of a selective sintering step by means of electromagnetic radiation of the powder, wherein the powder comprises at least one polymer or copolymer material, wherein the method comprises a predetermined and/or controlled cooling step after completion of the sintering step.

(36) The method according to (34) or (35), wherein the cooling step is predetermined and/or controlled so that the manufactured three-dimensional object has a final crystallinity within a range in which a balance of overall mechanical properties of young's modulus, tensile strength and elongation at break is improved. The Young's modulus of the polymer or copolymer is preferably at least 500MPa, more preferably at least 1000MPa and especially at least 2000MPa, the tensile strength is preferably at least 20MPa, more preferably at least 30MPa and especially at least 40MPa and the elongation at break is preferably at least 1%, more preferably at least 2%, even more preferably at least 5%, and especially at least 20%. To provide more specific values, for example for polyaryletherketone polymers and polyaryletherketone copolymers, the young's modulus is preferably at least 3000MPa, more preferably at least 3500MPa and especially at least 4000MPa, the tensile strength is preferably at least 50MPa, more preferably at least 70MPa and especially at least 90MPa and the elongation at break is preferably at least 1, 5%, more preferably at least 2%, still more preferably at least 3%, and especially at least 5%, and for polyamide polymers and polyamide copolymers the young's modulus is preferably at least 1000MPa, more preferably at least 1500MPa, still more preferably at least 2500MPa, the tensile strength is preferably at least 35MPa, more preferably at least 45MPa and especially at least 70MPa and the elongation at break is preferably at least 5%, more preferably at least 20%, still more preferably at least 40% and especially at least 60%.

(37) The method according to (35) or (36), wherein the final crystallinity of the manufactured object is 80% or less, preferably 50% or less, particularly 5 to 70%, more preferably 15 to 50% and particularly 15 to 35%.

(38) The method according to any one of (35) to (37), wherein the cooling step cools the object from a temperature 1 to 50 ℃, more preferably 1 to 30 ℃ and most preferably 1 to 10 ℃ below the Tm of the polymer or copolymer comprised by the powder to the Tg of the polymer or copolymer comprised by the powder at a cooling rate of 0.01 to 10 ℃, preferably 0.1 to 5 ℃, more preferably 1 to 5 ℃/min after completion of the object, wherein Tm is the melting temperature of the polymer or copolymer comprised by the powder and Tg is the glass transition temperature of the polymer or copolymer, respectively.

(39) The method according to any one of (35) to (38), wherein the polymer or copolymer is as defined in (7) to (33).

(40) Three-dimensional object obtained by selective sintering of a polymer, copolymer or polymer blend in powder form using electromagnetic radiation, wherein the final crystallinity is in a range that allows an improved balance of the overall mechanical properties of young's modulus, tensile strength and elongation at break. The young's modulus of the polymer or copolymer is preferably at least 500MPa, more preferably at least 1000MPa and especially at least 2000MPa, the tensile strength is preferably at least 20MPa, more preferably at least 30MPa and especially at least 40MPa, and the elongation at break is preferably at least 1%, more preferably at least 2%, even more preferably at least 5%, and especially at least 20%. To provide more specific values, for example, for polyaryletherketone polymers and polyaryletherketone copolymers, the young's modulus is preferably at least 3000MPa, more preferably at least 3500MPa and especially at least 4000MPa, the tensile strength is preferably at least 50MPa, more preferably at least 70MPa and especially at least 90MPa and the elongation at break is preferably at least 1.5%, more preferably at least 2%, even more preferably at least 3%, and especially at least 5%, and for polyamide polymers and polyamide copolymers, the young's modulus is preferably at least 1000MPa, more preferably at least 1500MPa, even more preferably at least 2500MPa, the tensile strength is preferably at least 35MPa, more preferably at least 45MPa and especially at least 70MPa and the elongation at break is preferably at least 5%, more preferably at least 20%, even more preferably at least 40% and especially at least 60%. Three-dimensional object obtained by selective sintering of a polymer, copolymer or polymer blend in powder form by means of electromagnetic radiation, wherein the final crystallinity is 80% or less, preferably 50% or less, in particular 5 to 70%, more preferably 15 to 50% and especially 15 to 35%, alone or in combination with (40).

(41) The three-dimensional object according to (40) to (41), wherein the polymer or copolymer is as defined in (7) to (33).

(42) An apparatus for producing a three-dimensional object from powder by selective sintering using electromagnetic radiation of the powder, comprising a temperature control device for use in a predetermined cooling of the object after completion of the process for producing the object.

(43) The apparatus according to (43), wherein the temperature control device is set according to the powder material.

(44) The apparatus according to (43) or (44), wherein the temperature control means is set according to the type of the polymer, copolymer or polymer blend contained in the powder material.

(45) Use of a polymer powder in a process for the manufacture of a three-dimensional object by selective electromagnetic radiation sintering, wherein the polymer is pre-selected to reduce the final crystallinity of the manufactured object.

(46) The use according to (46), wherein the crystallinity is reduced, so that the balance of the overall mechanical properties of Young's modulus, tensile strength and elongation at break is improved. The Young's modulus of the polymer or copolymer is preferably at least 500MPa, more preferably at least 1000MPa and especially at least 2000MPa, the tensile strength is preferably at least 20MPa, more preferably at least 30MPa and especially at least 40MPa and the elongation at break is preferably at least 1%, more preferably at least 2%, even more preferably at least 5%, and especially at least 20%. To provide more specific values, for example, for polyaryletherketone polymers and polyaryletherketone copolymers, the young's modulus is preferably at least 3000MPa, more preferably at least 3500MPa and especially at least 4000MPa, the tensile strength is preferably at least 50MPa, more preferably at least 70MPa and especially at least 90MPa and the elongation at break is preferably at least 1.5%, more preferably at least 2%, even more preferably at least 3%, and especially at least 5%, and for polyamide polymers and polyamide copolymers, the young's modulus is preferably at least 1000MPa, more preferably at least 1500MPa, even more preferably at least 2500MPa, the tensile strength is preferably at least 35MPa, more preferably at least 45MPa and especially at least 70MPa and the elongation at break is preferably at least 5%, more preferably at least 20%, even more preferably at least 40% and especially at least 60%.

(47) The use according to (46) or (47), wherein the crystallinity is reduced such that the final crystallinity is 80% or less, preferably 50% or less, in particular 5 to 70%, more preferably 15 to 50% and especially 15 to 35%.

(48) Use according to any one of (46) to (48), wherein the preselected polymer is as defined in (7) to (33).

(49) Use according to any of (45) to (48), wherein the polymer is further preselected to reduce the porosity of the three-dimensional object being produced.

Fig. 1 shows a laser sintering apparatus for the layered production of three-dimensional objects.

In order to improve the process for the manufacture of three-dimensional objects from powders by selective sintering processes by electromagnetic radiation of powders comprising at least one polymer or copolymer, the inventors carried out an intensive series of tests in order to find key factors particularly suitable for the manufacture of three-dimensional objects with improved mechanical properties.

It was therefore found that certain mechanical properties of three-dimensional objects produced by selective sintering of polymeric powder materials are significantly improved when the crystallinity of the produced object is limited and in particular when the crystallinity obtained is adjusted within a specific range. Surprisingly, this leads to a significant improvement of certain very advantageous mechanical properties including, but not limited to, high stiffness, high compressive strength, high impact strength, high maximum tensile and flexural strength as well as high elongation at break and high heat deflection temperature, while on the other hand the mutually compromised properties such as good chemical resistance and low post-shrinkage due to post-crystallization are well balanced. Furthermore, a reduction of the porosity of the manufactured object is possible, which additionally contributes to an improvement of the mechanical properties of the manufactured object.

Objects produced by a selective sintering process performed by electromagnetic radiation of a powder comprising at least one polymer typically have a much higher crystallinity value than objects produced by conventional polymer processing techniques like for example injection molding. That is, in a method of manufacturing a three-dimensional object from a powder by a selective sintering process using electromagnetic radiation of the powder comprising at least one polymer, for example of the type illustrated in fig. 1, the crystallinity values in the manufactured object tend to become prominent without crystallinity adjustment according to the invention. In particular, in processes configured in a layered fashion, high powder bed temperatures of about 1-50 ℃, preferably 1-30 ℃, even more preferably 1-20 ℃ and most preferably 1-10 ℃ below the melting point Tm of the polymer are generally used. The object is typically exposed to the higher processing temperatures for a considerable time and often undergoes a very long cooling time. To prevent or minimize curling of the part during construction, the processing temperature should be kept close to the melting point of the polymer powder to ensure good bonding between successive layers and to minimize the formation of voids due to improper melting of the powder particles. Thus, the temperature of the powder bed remains above the crystallization temperature Tc of the polymer throughout the build process. The formed object itself may be exposed to temperatures above Tc for extended periods of time. At the end of the build process, when all the heating sources of the sintering machine are turned off, a cooling process of the object through Tc is started due to natural heat losses of the environment. This takes several hours to several days because of the low thermal conductivity of the polymer powder and the large powder bed, depending on the polymer powder used and the process conditions, i.e. without predetermining a suitable cooling rate, which will probably further enhance the crystallization of the polymer object eventually during cooling. Without proper control, even post-crystallization of laser sintered polymer objects can occur. Thus, without properly observing the crystallinity properties according to the invention, a high and partly extremely high crystallinity is obtained in the manufactured object. Furthermore, without properly limiting the crystallinity, the relevant mechanical properties of the object may deteriorate.

On the other hand, in the selective sintering method according to the invention, the crystallinity in the manufactured object may advantageously be adjusted to be still sufficiently high to simultaneously ensure a positive influence of high chemical resistance, low post shrinkage at temperatures above Tg, or high stiffness for the manufactured object. Thus, an excellent balance of properties can be achieved by the present invention.

When the crystallinity of the objects made from the polymer powder material is suitably limited and preferably adjusted within a specific range, significant improvements in certain very advantageous mechanical properties like tensile strength, young's modulus and elongation at break can be achieved. 1) Pre-selecting a suitable type of polymer material, 2) customizing the structural properties and/or modifications of the polymer contained in the pre-selected powder, and/or 3) noting that a predetermined and/or controlled cooling step after the sintering process of the object is completed is a particularly effective and preferred means to limit and adjust the crystallinity value of the manufactured object.

Thus, according to a preferred embodiment of the invention, the predetermined and/or controlled cooling step is preferably applied to the object after completion of the object after sintering. The predetermined and/or controlled cooling step may be achieved by a predetermined slow cooling (which may be slower than the natural (passive) cooling), or by active cooling in order to provide a fast cooling. Since the conditions of the predetermined and/or controlled cooling step depend mainly on the type and specification of the polymer, copolymer or polymer blend used, useful set conditions of the cooling step can be tested experimentally provided that the final crystallinity is preferably 80% or less, preferably 50% or less, in particular 5 to 70%, more preferably 15 to 50% and especially 15 to 35%.

As explained for example when using PAEK materials as a representative example and trying to prevent curling, PEEK (polyetheretherketone) in contrast requires a well-defined low cooling rate after the sintering/structuring process of the object, whereas other PAEK materials like PEK (polyetherketone) preferably cool at a fast cooling rate after the sintering/structuring process. Preferred cooling rates for the PAEK after the sintering/structuring process are: when the manufactured object is cooled from the processing temperature (which is preferably a temperature 1-10 c below the melting point of the powder) to the Tg of the PAEK used, the cooling rate is preferably 0.01-10 c/min and more preferably between 0.1-5 c/min and most preferably between 1-5 c/min in order to minimize post-crystallization and curling of the part and to ensure low post-crystallization and low curling of the part. For example, pre-selecting the PEK powder and suitably employing a cooling rate of e.g. 0.3 ℃/min, a low crystallinity of e.g. 36% is achieved, which provides improved mechanical properties like tensile strength of 79MPa (see example 5). Further limiting the crystallinity to 31%, for example by employing a faster cooling rate, for example greater than 0.3 ℃/minute, provides a surprisingly further improved tensile strength of 88MPa (example 6).

However, the cooling rate after completion of the object also affects the curling of the object and thus the dimensional stability of the object. It has surprisingly been found that the cooling rate can be predetermined such that the three-dimensional object not only has a specific range of crystallinity in order to provide the above-mentioned desirable mechanical properties, but also has a high dimensional stability (i.e. it does not curl).

As exemplified, for example, using PAEK polymers, it has been found that PEEK powders, in contrast to PEK powders, require a slower cooling rate, for example, about 0.1-0.3 ℃/minute, in order to achieve low crystallinity and high dimensional stability (avoiding curling) (see examples 2 and 3). At higher cooling rates, this material will tend to curl.

In the following, some important structural properties or modifications of the polymer or copolymer material suitable for pre-selection for use in the selective sintering process by electromagnetic radiation are exemplified for PAEK polymers and copolymers. It will be apparent to those skilled in the art that the structural features or modifications described below can be equally applied to other types of polymers.

Particularly suitable alternative polymeric materials in addition to PEAK polymers and copolymers include, but are not limited to: polyamides, polyesters, polyethers, polyolefins, polystyrenes, polyphenylene sulfides, polyvinylidene fluorides, polyphenylene oxides, polyimides, and copolymers thereof. Suitable polyamide polymers or copolymers can be selected from: polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 612, polyamide 610, polyamide 1010, polyamide 1212 and copolymers comprising at least one of the foregoing polymers, and polyamide elastomers, such as polyether block amides, for exampleA mold material. Suitable polyester polymers or copolymers can be selected from polyalkylene terephthalates (e.g., PET, PBT) and their blends with 1, 4-cyclohexanedimethanolThe copolymer of (1). Suitable polyolefin polymers or copolymers can be selected from polyethylene and polypropylene. Suitable polystyrene polymers or copolymers can be selected from syndiotactic and isotactic polystyrenes.

Given the given molecular weight of the selected polymer, such as PAEK, as a reference, the inventors have long found that a slight increase in the molecular weight of the polymer contained in the powder easily leads to a surprisingly significant decrease in crystallinity in the manufactured object, which in turn translates into a significant improvement in certain very advantageous mechanical properties of the manufactured object. For example, pre-selecting a PEEK polymer material with a higher molecular weight, typically Mn-32,000 and Mw-99,000, rather than a molecular weight typically of Mn-23,000 and Mw-68,000, helps to reduce the crystallinity of the fabricated object to below 50% (see, e.g., examples 1 and 2 show a reduction from 52% to 45%). Although an increase in molecular weight will reduce density and thus increase porosity, it primarily contributes to an increase in tensile strength and elongation at break (see, e.g., examples 1 and 2 showing a substantial increase in tensile strength from 44MPa to 71MPa and an increase in elongation at break from-1% to-2%). Above a certain molecular weight, however, a saturation effect occurs. A greater reduction in crystallinity and a greater improvement in mechanical properties are no longer possible (see example 3). Therefore, the molecular weight Mn is preferably adjusted to at least 9,000, preferably 10,000-100,000, more preferably 15,000-50,000 and most preferably 20,000-35,000 or the Mw is preferably adjusted to 20,000-500,000, preferably 40,000-200,000 and more preferably 50,000-125,000.

Similar explanations as described above for molecular weight apply to the melt viscosity of the polymer or copolymer. The melt viscosity related to the molecular weight of the polymer or copolymer is as follows: the higher the molecular weight of the polymer or copolymer, the higher its melt viscosity. Thus, for PAEK polymers or copolymers, in the range of 0.05-1.0kN s/m²More preferably 0.15-0.6kN s/m²And in particular 0.2-0.45kN s/m²Melt viscosities in the range are preferred.

The general structure of PAEK or PAES polymers and copolymers preferred for the construction of laser sintered objects is shown in the general formula given below, where the structural uniqueness required to obtain the desired low crystallinity is further described below:

Ar₁，Ar₂and Ar₃Each independently represents an unsubstituted or substituted mono-or polycyclic aromatic hydrocarbon, wherein the optional substituents may be selected from:

Rf₁、Rf₂、Rf₃: each independently represents C₁-C₆Straight-chain or branched or cyclic alkyl and alkoxy groups, and aryl groups, preferably Me, i-Pr, t-Bu, Ph, in which each Ar₁，Ar₂And Ar₃May each have one or more Rf₁、Rf₂、Rf₃A substituent group is selected from the group consisting of,

x ═ O and/or S

Y ═ CO and/or SO₂

Z＝SO₂CO, O and/or S

a is a lower integer greater than 0, preferably lower than 12, more preferably from 1 to 6 and especially from 1 to 3,

b is a lower integer greater than 0, preferably lower than 12, more preferably from 1 to 6 and especially from 1 to 3,

c is 0 or a lower integer, preferably less than 12, more preferably from 1 to 6 and especially from 1 to 3,

n represents the degree of polymerization.

In the above formulae, the indices a, b and c respectively denote the number of the respective units in brackets in the repeating units of the polymer or of the copolymer, wherein one or more units of the same type, for example the unit denoted by index a, can be located between units of different types, for example the units denoted by indices b and/or c. The position of the respective unit in the repeating unit can be derived from the abbreviations of the PAEK derivatives.

For PEK, for example, the repeating units include: ar (Ar)₁Is unsubstituted phenylene, X is O and a ═ 1, Ar₂Is unsubstituted phenylene, Y is CO, b ═ 1, and c ═ 0. Thus, PEK has the general structure:

wherein n represents the degree of polymerization. As another example, for PEEK, the repeating unit comprises: ar (Ar)₁Is unsubstituted phenylene, X is O and a ═ 2, Ar₂Is unsubstituted phenylene, Y is CO and b ═ 1 and c ═ 0. Referring to the positions of the respective ester and ketone units, the abbreviation PEEK indicates that there is one ketone (K) unit after two ester (E) units, and thus PEEK has the structure of the general formula

Wherein n represents the degree of polymerization. As yet another example, for PEKEKK, the repeating unit comprises: ar (Ar)₁Is unsubstituted phenylene, X is O and a ═ 2, Ar₂Is unsubstituted phenylene, Y is CO and b ═ 3 and c ═ 0. With reference to the position of the respective ester and ketone units, the abbreviation PEKEKK indicates that one ester (E) unit is followed by one ketone (K) unit, then the ketone unit is followed by one ether unit, and then 2 ketone units, so that PEKEKK has the structure of the formula

Wherein n represents the degree of polymerization.

For PAEK polymers and copolymers, the degree of polymerization n is preferably from 10 to 1,000, more preferably from 20 to 500 and especially from 40 to 250.

Aromatic hydrocarbon radical Ar₁、Ar₂And Ar₃The larger the required space, the more the aromatic hydrocarbon groups resemble the rigid rod-shaped segments and the lower the final crystallinity of the object produced. Thus, it is preferred that the aromatic hydrocarbon group Ar₁、Ar₂And Ar₃Each independently selected from 1, 4-phenylene, 4, 4 '-biphenylene, 4, 4' -isopropylidenediphenylene, 4, 4 '-diphenylsulfone, 1, 4-, 1, 5-and 2, 6-naphthylene, 4, 4' -biphenylene and α -bis (4-phenylene) phthalide.

Side chain Rf on an aromatic Hydrocarbon of the backbone chain₁、Rf₂、Rf₃The mobility of the polymer chains in the melt is influenced and therefore preferably allowed to influence favorably, thereby reducing the final crystallinity of the manufactured object.

In addition, the ratio of the amount of ketone group Y to the amount of ether group or thioether group X is preferably from 1: 4 to 4: 1. Within this ratio range, the crystallinity can be significantly reduced. For example, when comparing the use of PEK (ratio 1: 1) and PEEK (ratio 2: 1) having similar typical molecular weights, PEK is preferred over PEEK in terms of achieving lower crystallinity. On the other hand, when using PEEK, a similarly controlled crystallinity can also be achieved by taking other compensatory control measures, for example by using correspondingly higher molecular weight PEEK or by suitably predetermining the post-sintering cooling at a high cooling rate.

Another possibility to tailor the polymer in order to achieve the final crystallinity after the selective sintering process, which is the desired limitation of the manufactured object, is to use a suitable copolymer. For PAEK, its copolymers with Polyarylethersulfones (PAES) are preferred, in particular Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -diblock copolymers or PAEK/PAES/PAEK-triblock copolymers, more particularly Polyetherketone (PEK)/Polyethersulfone (PES) -diblock copolymers or PEK/PES/PEK-triblock copolymers. It has been found that the higher the amount of polyarylethersulfone component, the lower the crystallinity of the manufactured object. Thus, in particular, the ratio of the amount of sulfone groups Z to the amount of ketone groups Y is preferably between 50: 50 and 10: 90. Within this ratio range, the glass transition temperature (Tg) and the melting point (Tm) of the polymer material can be adjusted so as to be suitable for processing the polymer in an apparatus for manufacturing three-dimensional objects by a selective sintering method using electromagnetic radiation. In order to provide a suitable processing temperature for the selective sintering process, the PEK/PES copolymer preferably has a Tg of greater than 180 ℃ and a melting temperature Tm of 300-430 ℃.

It has further been found that the end groups of the backbone chains of the polymer or copolymer can act as crystallization seeds during crystallization. Thus, the end groups of the polymer or copolymer may be derivatized in order to interfere with crystallization and thus limit the crystallinity of the fabricated object.

The end groups may also be selected such that they cause the polymer or copolymer chain to be extended by a chemical reaction between the end groups (preferably at a temperature above the Tm of the polymer), for example by a polycondensation reaction, electrophilic or nucleophilic aromatic substitution, coupling reaction, or the like. The crystallinity of the manufactured object is reduced due to the increased molecular weight.

The end groups of the backbone chains of the polymer or copolymer depend on the type of monomers used for the synthesis and on the type of polymerization reaction. In the following, two different types of PAEK synthesis routes are shown, resulting in different types of PAEKs with different end groups.

PAEKs can be synthesized in two general ways, namely by electrophilic aromatic substitution (friedel-crafts-acylation) or nucleophilic aromatic substitution. For example, in the nucleophilic synthesis of PAEK, 1, 4-bishydroxybenzene is polymerized with a 4, 4' -dihalogenobenzophenone component:

xHO-Ph-OH+(y+1)Hal-Ph-CO-Ph-Hal→Hal-Ph-CO-Ph-[O-Ph-O]x[Ph-CO-Ph]y-Hal

where Hal is F, Cl, Br and x and y represent the number of monomers introduced into the polymer.

As a result, the PAEK backbone chain in the PEEK example above may, not at either end of the backbone chain or at one (not shown) or both (shown) ends of the backbone chain, be terminated by residual halogen groups after polymerization, most suitably by fluorine, optionally alternatively by chlorine or bromine. The same applies to the synthesis of PAEK or Polyethersulfone (PAES) copolymers in which the dihalogenated ketone units may be partially substituted by dihalogenated aromatic sulfones. The aromatic dihydroxy component can likewise be partially or completely replaced by a dithiol component.

For example, the halogen-substituted end of the polymer can be derivatized by a termination reaction with phenol:

2Ph-OH+Hal-Ph-CO-Ph-[O-Ph-O]x[Ph-CO-Ph]y-Hal→Ph-O-Ph-CO-Ph-[O-Ph-O]x[Ph-CO-Ph]y-O-Ph

preferably, Hal in the above formula is F.

In the case of the synthesis of PAEK polymers or copolymers by electrophilic aromatic substitution, diacyl aromatic hydrocarbons (diacrylamides), such as aromatic diacids or preferably aromatic diacid chlorides or aromatic dianhydrides, are polymerized with a bis-aromatic ether or thioether component. For example, for PEKK, this may result in PEKK polymers or copolymers having phenyl groups not on either end of the backbone chain or on one (not shown) or both (shown) ends of the backbone chain:

xR_AOC-Ph-COR_A+(y+1)Ph-O-Ph→Ph-O-Ph-[OC-Ph-CO]x[Ph-O-Ph]y-H

wherein R is_AIs Cl or-OH and x and y represent the number of monomers introduced into the polymer.

Alternatively, synthetic methods via a single monomer route using, for example, aromatic monoacids can be employed.

For example, the phenyl group at the end of the polymer can be derivatized by a termination reaction with benzoyl chloride:

2Ph-COCl+Ph-O-Ph-[OC-Ph-CO]x[Ph-O-Ph]y-H→Ph-CO-Ph-O-Ph-[OC-Ph-CO]x[Ph-O-Ph]y-OC-Ph

regardless of the choice of nucleophilic or aromatic substitution reaction, in order to slow the crystallization of the polymer, the end groups are preferably substituted, for example such that the PAEK polymer has the general formula:

R_T-U-[PAEK]-U-R_T

wherein U is a linking moiety, e.g. NH, O, CO, CO-O-, SO, a single bond, - (CH)₂) k, wherein k is 1-6, etc.; and left-hand and right-hand structural parts R_TMay be identical or different structural groups, usually the structural moiety R_TAre the same. Preferably, R_TSelected from unsubstituted or substituted aliphatic or aromatic hydrocarbon residues. U may be formed by direct reaction with the end of a polymer or copolymer, for example a monofunctional hydroxy compound may form O as U, or it may be introduced as a substituent of a terminating reagent, for example HO-Ph-COO-tert-butyl may form COO as U.

Furthermore, if it is desired to increase the crystallization rate in order to suitably adjust the crystallinity of the three-dimensional object produced, the polyaryletherketones having halogenated end groups can be end-capped with ionic groups, like for example phenolates such as NaOPhSO₃Na or NaOPhCPhOPhSO₃And (5) stopping by Na. Subsequent acidification of the phenate with, for example, HCl results in the formation of-SO₃H end groups, which show a slightly reduced nucleation (nucleation) effect.

The polymers or copolymers may be blended together with the alloy components in a blend, wherein a blend of at least two different polymers or copolymers is used. It is preferred in the blend that at least one component of the blend reduces the final crystallinity of the manufactured object.

Similar structural properties or modifications as explained for PAEK can equally apply to the alternative polymer or copolymer materials described above.

The powder may, in addition, be a composite powder comprising, in addition to the matrix of the respective polymer, copolymer or blend, one or more fillers and/or additives. Fillers can be used to further improve the mechanical properties of the manufactured object. For example, fillers such as fibers, including but not limited to carbon fibers, glass fibers, kevlar fibers, carbon nanotubes, or fillers having a low aspect ratio (glass beads, aluminum sand, etc.) or mineral fillers such as titanium dioxide may be incorporated into the powder comprising at least one polymer or copolymer. In addition, processing aids which improve the processability of the powders, for example free-flowing agents such as those of the Aerosil series (e.g. Aerosil r974, Aerosil200), or other functional additives such as heat stabilizers, oxidation stabilizers, colouring pigments (carbon black, graphite, etc.) may be used.

From the findings of the present invention it can be generally concluded that the following structural properties or modifications of the polymer or copolymer contribute to the restricted crystallinity behavior and are particularly preferred when a specific type of polymer or copolymer is preselected, for example among Polyamides (PA), Polyaryletherketones (PAEK), polyesters, polyethers, polyolefins, polystyrenes, polyphenylene sulfides, polyvinylidene fluorides, polyphenylene ethers, polyimides and copolymers thereof (preselected):

(i) higher molecular weights Mn or Mw or melt viscosities are selected,

(ii) using a long chain length or a high degree of polymerization n,

(iii) introducing an aromatic group into the backbone chain, each independently representing an unsubstituted or substituted mono-or polycyclic aromatic hydrocarbon; preferably, the aromatic groups are each independently selected from 1, 4-phenylene, 4, 4 '-biphenylene, 4, 4' -isopropylidenediphenylene, 4, 4 '-diphenylsulfone, 1, 4-, 1, 5-and 2, 6-naphthylene, 4, 4' -biphenylene and α -bis (4-phenylene) phthalide,

(iv) the aromatic group being substituted by one or more side chains, wherein the side chains are independently and independently selected from C₁-C₆Linear or branched or cyclic alkyl and alkoxy groups, and aryl groups, preferably the side chains are individually and independently selected from methyl, isopropyl, tert-butyl or phenyl,

(v) modification of the end groups of the backbone chain of the polymer or copolymer, preferably by aliphatic or aromatic end groups, and

(vi) blending or preparing an alloy is performed by blending at least two different polymers or copolymers.

Examples

The crystallinity of the manufactured object can be determined by various methods known to those skilled in the art. The crystallinity can be determined on the basis of Differential Scanning Calorimetry (DSC) according to DIN53765, which is used as reference method according to the invention. Using the values found in the technical publications for theoretically 100% crystalline polymers, for example 130J/g for PEEK and 160J/g for PEK (PCDawsonndDJBlundell, Polymer1980, 21, 577-:

for objects manufactured from composite powders, i.e. powders comprising, in addition to a polymer, copolymer or polymer blend, one or more fillers or additives, the crystallinity value relates to the polymer matrix of the composite material, which can also be calculated according to the formula defined above.

Crystallinity can also be determined by wide angle X-ray scattering (WAXS) measurements. Such procedures are well known to those skilled in the art.

As reference method for the present invention, the crystallinity is determined in the following examples on the basis of DSC measurements carried out in accordance with DIN53765 on Mettler-Toledo DSC 823. DSC samples were prepared from the middle of astm d638 tensile bars prepared at a distance of at least 5cm in the x, y direction from the edge of the exchangeable frame on the laser sintering machine. The crystallinity is then calculated by using the formula shown above.

The density was measured according to ISO1183 on a Kern770-60 balance with satorius densitometratino setydk 01.

Porosity is calculated from the formula:

d_100％theoretical density of 100% crystalline PAEK

d_0％Theoretical density of amorphous PAEK

Crystallinity of Xc ═ PAEK moieties

Theoretical 100% crystalline PEEK (d)_100％＝1.4g/cm³) And PEK (d)_100％＝1.43g/cm³) And amorphous PEEK (d)_0％＝1.265g/cm³) And PEK (d)_0％＝1.272g/cm³) The density values of (A) are well known in the literature (PCDawsonnand DJBlundell, Polymer1980, 21, 577-.

The porosity can also be determined by micro-computer aided tomography (micro-computer aided tomography) if the theoretical density value of the polymer is not known. A useful apparatus is for example μ -CT40 supplied by SCANCOMedicalAG, Brutiselen, Switzerland. Such procedures are well known to those skilled in the art.

In the examples, the melt viscosity can be measured according to the teaching of US patent 2006/0251878A1 in a capillary viscometer with a wolfram-carbide nozzle at 400 ℃ and 1000s^-1Is measured at a shear rate of (2).

The following examples are merely illustrative of the invention and they should not be construed as limiting the scope of the invention in any way. Examples and modifications, or other equivalents thereof, will become apparent to those skilled in the art upon reading the entire disclosure.

Example 1 (not according to the invention)

A powder made from PEEK (commercially available from VictrexPlc, thornton cleveleys, lancashirey 54QD, great britain) having a mean particle size distribution of 48 μm, wherein the PEEK polymer has a molecular weight of Mn 23,000 and Mw 65,000 and a molecular weight of 0.15kN s/m²Is heat treated in an oven at a temperature above the glass transition temperature.

Having a density of 0.45g/cm³The bulk density PEEK powder of (a) was processed on a laser sintering machine of the P700 type, which has been modified by the EOS company for high temperature applications. The temperature of the process chamber was 335 ℃.

After the laser sintering process was completed, the cooling rate was controlled by post-heating between 335 ℃ and the Tg (145 ℃) of PEEK. The cooling rate showed a maximum average of 0.3 ℃/min.

The part had the following properties:

density 1.316g/cm³

Porosity (calculated from density/crystallinity) 1.4%

Degree of crystallinity (by DSC) 52%

Tensile test (astm d638, TypeI):

young's modulus 4500MPa

Tensile strength of 44MPa

Elongation at break 1.04%

Example 2 (according to the invention)

A powder made from PEEK (commercially available from VictrexPlc, thornton cleveleys, lancashirey 54QD, great britain) having a mean particle size distribution of 48 μm, wherein the PEEK polymer has a molecular weight of Mn-32,000 and Mw-65,000 and a molecular weight of 0.45kN s/m²Melt ofBulk viscosity, heat treated in an oven at a temperature above the glass transition temperature.

Having a density of 0.40g/cm³The bulk density PEEK powder of (a) was processed on a laser sintering machine of the P700 type, which has been modified by the EOS company for high temperature applications. The temperature of the process chamber was 335 ℃.

The part had the following properties:

density 1.303g/cm³

Porosity (calculated from density/crystallinity) 1.6%

The crystallinity is 45%

Tensile test (astm d638, TypeI):

young's modulus 4200MPa

Tensile strength of 71MPa

Elongation at break 1.9%

Example 3 (according to the invention)

A powder was made from PEEK (commercially available from Victre XPlc Co., Thornton Cleveleys, LancashireFY54QD, GreatBortrinian) having a mean particle size distribution of 48 μm, wherein the PEEK polymer had a 0.54kN s/m²Is heat treated in an oven at a temperature above the glass transition temperature.

PEEK powder was processed on a laser sintering machine of the P700 type, which has been modified by EOS corporation for high temperature applications. The temperature of the process chamber was 335 ℃.

The part had the following properties:

density 1.300g/cm³

The crystallinity is 42%

Porosity (calculated from density/crystallinity) 1.6%

Tensile test (astm d638, TypeI):

young's modulus of 3800MPa

Tensile strength of 74MPa

Elongation at break 2.2%

Example 4 (according to the invention)

A powder made from PEK (commercially available from VictrexPlc, thornton cleveleys, lancashirey 54QD, great britain) having an average particle size distribution of 48 μm, wherein the PEK polymer has a molecular weight of Mn 23,000 and Mw 65,000 and a molecular weight of 0.22kN s/m²Is heat treated in an oven at a temperature above the glass transition temperature.

PEK powder was processed on a laser sintering machine of type P700, which has been modified by EOS corporation for high temperature applications. The process chamber temperature was 365 ℃.

After the laser sintering process is complete, the cooling rate is controlled by post-heating between 365 ℃ and the Tg (157 ℃) of PEK. The cooling rate showed a maximum average of 0.3 ℃/min.

The part had the following properties:

density 1.310g/cm³

The crystallinity is 39%

Porosity (calculated from density/crystallinity) 1.8%

Tensile test (astm d638, TypeI):

young's modulus 4220MPa

Tensile strength of 80MPa

Elongation at break 2.2%

Example 5 (according to the invention)

A powder made from PEK (commercially available from VictreXPlc, Inc., Thornton Cleveleys, LancashireFY54QD, GreatBortrinain) having a mean particle size distribution of 48 μm, wherein the PEK polymer has a 0.45kN s/m²Is heat treated in an oven at a temperature above the glass transition temperature.

The part had the following properties:

density 1.277g/cm³

The crystallinity is 36%

Porosity (calculated from density/crystallinity) 3.9%

Tensile test (astm d638, TypeI):

young's modulus of 3820MPa

Tensile strength of 79MPa

Elongation at break 2.5%

Example 6 (according to the invention)

PEK powder was processed on a laser sintering machine of type P700, which has been modified by EOS corporation for high temperature applications, as described in example 4.

After the laser sintering process is complete, all heating of the laser sintering machine is turned off. The average value of the cooling rate was > 0.3 deg.C/min.

The part had the following properties:

density 1.285g/cm³

Porosity (calculated from density/crystallinity) 2.8%

The crystallinity is 31%

Tensile test (astm d638, TypeI):

young's modulus 3950MPa

Tensile strength of 88MPa

Elongation at break was 2.8%.

Claims

1. Method for producing a three-dimensional object by selective sintering of a polymer in powder form by electromagnetic radiation, comprising the steps of:

(i) selecting a melt viscosity of 0.2-1.0kN s/m²A powder of the polyaryletherketone polymer or polyaryletherketone copolymer of (a);

(ii) (ii) subjecting the powder comprising polyaryletherketone polymer or polyaryletherketone copolymer of step (i) to selective sintering by electromagnetic radiation to form the three-dimensional object;

(iii) after the three-dimensional object is completed, the thickness is increased by 0.01-a cooling rate of 10 ℃/min to move the three-dimensional object from the melting temperature T of the polymer or copolymer contained in the powder_mCooling to a temperature of 1-50 ℃ below the glass transition temperature T of the polymer or copolymer contained in the powder_g；

Wherein the three-dimensional object produced has a final crystallinity of 5-45%.

2. The method of claim 1, wherein the three-dimensional object produced has a porosity of less than 5%.

3. The method according to claim 1, wherein the three-dimensional object produced has a porosity of less than 3%.

4. The process according to claim 1, wherein the powder comprising a polyaryletherketone polymer or a polyaryletherketone copolymer has a melting point T in the range of 280-450 ℃_m。

5. The process according to claim 1, wherein the polyaryletherketone copolymer is a Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -diblock copolymer or a PAEK/PAES/PAEK-triblock copolymer.

6. The process according to claim 1, wherein the polyaryletherketone copolymer is a Polyetherketone (PEK)/Polyethersulfone (PES) -diblock copolymer or a PEK/PES/PEK-triblock copolymer.

7. The method according to claim 4, wherein the three-dimensional object produced has a porosity of less than 5%.

8. The method according to claim 7, wherein the three-dimensional object produced has a porosity of less than 3%.

9. The method according to claim 1, wherein said powder has a temperature in the range of 100-450 ℃Melting point of (2)_m。

10. The method according to claim 1, wherein said powder has a melting point T in the range of 150-400 ℃_m。

11. The method according to claim 1, wherein said powder has a melting point T in the range of 250-400 ℃_m。

12. A three-dimensional object made by the method according to claim 1.

13. The three-dimensional object according to claim 12, wherein the porosity is below 5%.

14. The three-dimensional object according to claim 12, wherein the porosity is lower than 2%.

15. The three-dimensional object according to claim 12, wherein the density is at least 1.24g/cm³。

16. The three-dimensional object of claim 12, wherein the density is at least 1.26g/cm³。

17. The three-dimensional object according to claim 12, wherein the density is at least 1.28g/cm³。

18. The three-dimensional object according to claim 12, wherein the density is greater than 1.30g/cm³。