Patent Application
20130177767
This application claims priority to German Application No. 10 2012 200 161.1, filed Jan. 6, 2012, the disclosure of which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to an apparatus for the layer-by-layer production of three-dimensional objects, to processes for layer-by-layer production, and also to corresponding shaped articles.
2. Description of the Related Art
The rapid provision of prototypes is a task frequently encountered in very recent times. Processes which permit this are termed rapid prototyping/rapid manufacturing, or else additive fabrication processes. Particularly suitable processes use operations based on pulverulent materials, where the desired structures are produced layer by layer, by selective melting and solidifying. Supportive structures for overhangs and undercuts are not needed in this method, since the plane of the construction field that surrounds the melted regions provides sufficient support. The subsequent operation of removing supports is likewise omitted. The processes are also suitable for producing short runs. The temperature of the construction chamber may be selected such that no warpage of the structures produced layer by layer occurs during the construction procedure.
One process which is especially suitable for the purposes of rapid prototyping is selective laser sintering (SLS). In this process, plastics powders in a chamber are exposed briefly and selectively to a laser beam, and this causes melting of the powder particles impacted by the laser beam. The melted particles coalesce and rapidly resolidify to give a solid mass. Three-dimensional bodies can be produced simply and rapidly by this process, by repeatedly exposing a constant succession of freshly applied layers to light.
The laser sintering (rapid prototyping) process for producing shaped articles from pulverulent polymers is described in detail in U.S. Pat. No. 6,136,948 and WO 96/06881 (both DTM Corporation). A wide variety of polymers and copolymers is described as suitable for this application, and include polyacetate, polypropylene, polyethylene, ionomers and polyamide.
Other highly suitable processes are the SIB process (selective inhibition of bonding) as described in WO 01/38061, or a process as described in EP 1015214. Both processes operate with extensive infrared heating to melt the powder. The selectivity of the melting operation is achieved in the first case by the application of an inhibitor and in the second process by a mask. DE 10311438 describes a further process, wherein the energy needed for melting is introduced by a microwave generator, and the selectivity is achieved by application of a susceptor. A further process is described in WO 2005/105412, where the energy needed for melting is introduced as electromagnetic radiation, and, likewise, the selectivity is achieved by application of an absorber.
A problem with the process described above is that the powders used must be pourable, in order to allow flawless layer application. Only if layer application is flawless is it possible to produce three-dimensional objects of high quality. If pourability is inadequate, regions of the construction field are coated inadequately, or not at all, with powder. Moreover, channels, waves or fissures may appear in the powder bed. In processing, this leads to problems, and so at the end of the process the three-dimensional objects produced exhibit defects.
The pourability of the powders employed can be improved by addition of additives, as described in EP 1443073. A disadvantage of this procedure is that the additives added are then also part of the three-dimensional objects produced, and in certain applications this may be undesirable for these objects. Moreover, adding additives to raise the pourability usually also has the effect of increasing warpage in the three-dimensional objects produced. Furthermore, very fine powders cannot be made pourable or can be given only limited pourability, even with the addition of additives. However, it would be desirable to use very fine powders, in order to increase the surface quality of the components and to minimize the warpage tendency.
It is an object of the present invention, therefore, to improve the application of low-pourability powders in the production of three-dimensional objects.
It is a further object to provide an apparatus for the preparation of three dimensional objects by a layer by layer method.
It is a still further object of the present invention to provide a method for layer by layer production of three dimensional objects or articles which may employ powders having low-pourability.
These and other objects have been achieved by the present invention, the first embodiment of which includes an apparatus for layer-by-layer production of three-dimensional objects, comprising:
a construction chamber having a planar base;
an adjustable-height construction platform comprising a construction field contingent with the planar base,
an electromagnetic radiation source having a control unit and a lens; and
a moveable material application unit on the planar base, the unit comprising a doctor blade;
wherein
a beam of electromagnetic radiation emitted from the source is focused by the lens on an object area of the construction platform,
a height of the construction platform is adjustable in a downward direction perpendicular to the planar base,
the material application unit slides in a direction across the construction field,
the doctor blade of the material application unit is moveable in a direction parallel to the plane of the base and in a direction perpendicular to the direction of material application, and
an edge of the doctor blade closest to the construction field is a non-continuous straight line.
In one preferred embodiment, the edge of the doctor blade comprises at least two recesses and a geometric shape of the recesses is selected from the group consisting of semicircular, triangular, trapezoidal and rectangular.
In another embodiment the present invention provides a process for layer-by-layer production of three-dimensional objects, comprising:
applying a powder layer onto a construction platform having a planar base;
irradiating the powder with a beam of electromagnetic radiation to fuse the powder in an object pattern;
solidifying the fused powder; and
repeating the powder layer application, irradiation and solidification the obtain a three-dimensional object;
wherein
the powder layer is applied with a moveable material application unit comprising a doctor blade,
an edge of the doctor blade closest to the construction platform is a non-continuous straight line,
the application unit is moved across the construction platform parallel to the planar base, and
the doctor blade is additionally moved in a direction perpendicular to the direction of the application unit across the construction platform and parallel to the planar construction platform.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
In a first embodiment the present invention provides an apparatus for layer-by-layer production of three-dimensional objects, comprising:
a construction chamber having a planar base;
an adjustable-height construction platform comprising a construction field contingent with the planar base,
an electromagnetic radiation source having a control unit and a lens; and
a moveable material application unit on the planar base, the unit comprising a doctor blade;
wherein
a beam of electromagnetic radiation emitted from the source is focused by the lens on an object area of the construction platform,
a height of the construction platform is adjustable in a downward direction perpendicular to the planar base,
the material application unit slides in a direction across the construction field,
the doctor blade of the material application unit is moveable in a direction parallel to the plane of the base and in a direction perpendicular to the direction of material application, and
an edge of the doctor blade closest to the construction field is a non-continuous straight line.
As shown in
The “corresponding points” of the object may each constitute a layer of the sliced contour of the object, which are to be melted or sintered into the powder bed in steps by the driving of the laser beam.
The recesses may take on various geometric shapes. For example, the recesses may be semicircular, triangular, trapezoidal or rectangular. There may preferably be at least two, more preferably, at least five, and most preferably, at least ten recesses included. Rectangular recesses produce comb-like sliders. Triangular or trapezoidal recesses may lead to beads which are triangular, for example, and which may point with their peaks in the direction of the plane of the construction field.
The inventors have surprisingly found that with an apparatus of the present invention it may be possible to apply low-pourability powders, thereby making it possible to reduce the addition of additives conventionally used to improve pourability or to eliminate the use of such additives entirely. In this respect, it is especially surprising that powders having low pourability may be employed to produce three dimensional objects in an apparatus (7) according to the present invention which is configured in the form of a slider whose edge facing the powder to be applied is configured as a non-continuous straight line and may be moved perpendicular to the direction of application and parallel to the plane of the construction field. Preferably, during powder application, the apparatus may additionally be moved perpendicular to the direction of application and parallel to the plane of the construction field.
In a further preferred embodiment, the apparatus may have a heating element for temperature control of the construction chamber. The heating element may be used to control the temperature of the construction chamber to an ideal temperature for producing the three-dimensional object.
The wiper may be constructed of any suitable material and may preferably be made of a material which is not reversibly diffracted or deflected while the powder is being applied. A non-elastic plastic or metal may be preferred materials.
In
For improved powder application it may be possible to combine two or more of the embodiments described above. The recesses in the series of wipers may be designed to allow a continuous powder bed to be established. In this case there may be no need for a vibratory movement of the apparatus.
A further embodiment of the invention is shown in
The quality of the applied layer may be additionally enhanced if after the application of powder according to the apparatus of the invention, the plane of the construction field is smoothed by means of a roller or a wiper. The roller or wiper may be constructed from any of metals, ceramics and high-temperature plastics. Suitable high-temperature plastics may be polyimides, polyaryletherketones, polyphenolensulfides, polyarylsulfones and fluor polymers.
In one further embodiment the apparatus for the layer-by-layer production of three-dimensional objects may additionally comprise a vibration generator, which sets the construction platform (6) into vibration, and thus, may increase the density of the powder bed.
In order to further increase the ease of application, the powder may be regularly loosened. This treatment may be accomplished by rotational or translational movement of a conventional apparatus for such purpose through the powder prior to application. This may take place during the application of the powder or during a metering procedure. This measure may counter the formation of lumps in the powder prior to application.
Fine powders which have low pourability or are unpourable, in particular, have a tendency to adhere to an apparatus for powder application. These adhesions then lead, during powder application, to channels in the construction field. These adhesions may be eliminated by use of a stripping apparatus, such a brush. Stripping apparatuses of this kind are known to those skilled in the art. The apparatus for powder application travels over the stripper, and as it does so, the adhesions may be eliminated and then fall into an overflow. The material for the stripper should be selected so as to ensure a sufficient force for eliminating the adhesions on the apparatus for powder application, but such that at the same time there is no damage to the apparatus for powder application. The stripper may consist, for example, of plastic or metal.
In another embodiment, the present invention provides a process for the layer-by-layer production of three-dimensional objects, where the powder is applied to the construction platform or over a previous layer, by an application apparatus (7) according to the invention. According to this embodiment, during powder application force may be placed on the powder not only in the direction of application but also by another force which is directed perpendicular to the direction of coating and parallel to the plane of the construction field. Particularly preferred are processes for the layer-by-layer production of three-dimensional objects, that are conducted in an apparatus comprising a construction chamber (10) with an adjustable-height construction platform (6), with an apparatus (7) for applying, to the construction platform (6), a layer of a powder solidifiable by exposure to electromagnetic radiation, and with irradiation equipment comprising a radiation source (1) which emits electromagnetic radiation, a control unit (3) and a lens (8) which is located in the beam path of the electromagnetic radiation, for irradiating points of the layer corresponding to the object (5), and where, during application of the solidifiable powder, the powder is acted on not only by the force in the direction of application but also by a force which is directed perpendicular to the direction of coating and parallel to the plane of the construction field.
The process according to the present invention may be especially suitable for the application of powders of low-pourability, powders which are non-pourable powders and/or for application of very fine polymer powders.
The processes according to the invention which can produce shaped parts according to the invention from powders are described in more detail below, but without any intention that such description be limiting unless otherwise expressly stated.
In principle, any of the polymer powders known to the person skilled in the art may be suitable for use in the apparatus of the invention or in the process of the invention. Thermoplastic and thermoelastic materials may be particularly suitable, and include polyethylene (PE, HDPE, LDPE), polypropylene (PP), polyamides, polyesters, polyester esters, polyether esters, polyphenylene ethers, polyacetals, polyalkylene terephthalates, in particular polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polymethyl methacrylate (PMMA), polyvinyl acetal, polyvinyl chloride (PVC), polyphenylene oxide (PPO), polyoxymethylene (POM), polystyrene (PS), acrylonitrile-butadiene-styrene (ABS), polycarbonates (PC), polyether sulphones, thermoplastic polyurethanes (TPU), polyaryletherketones, in particular polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyetherketone (PEK), polyetheretherketone-ketone (PEEKK), polyaryletheretheretherketone (PEEEK) or polyetherketoneetherketoneketone (PEKEKK), polyetherimides (PEI), polyarylene sulphides, in particular polyphenylene sulphide (PPS), thermoplastic polyimides (PI), polyamideimides (PAT), polyvinylidene fluorides, and also copolymers of the said thermoplastics, such as a polyaryletherketone (PAEK)/polyarylether sulphone (PAES) copolymer, mixtures and/or polymer blends. With special preference, the polymer powder comprises at least one polyamide or polyaryletherketone. An especially preferred polymer powder comprises or consists of polyamide, more particularly PA6, PA66, PA610, PA613, PA1010, PA106, PA11, PA12, PA1012, PA1013 or mixtures of these.
Metallic powders, including iron, titanium or aluminium, or ceramic powders may also be suitable for use according to the present invention. Polymer powders may be particularly preferred.
In operation, an engineering program or the like may be first used to generate or store, in a computer, data concerning the shape of the object (5) to be produced. For the production of the object, the data may be processed in such a way that the object is dissected into a large number of horizontal layers which are thin in comparison with the size of the object, and the shape data are provided for each of this large number of layers, for example in the form of data sets, e.g. CAD data. The generation and processing of the data for each layer may take place prior to the production process or else simultaneously with the production of each layer.
The construction platform (6) is then first moved by the height-adjustment apparatus to the highest position, in which the surface of the construction platform (6) is in the same plane as the surface of the construction chamber, and may then be lowered by an amount corresponding to the intended thickness of the first layer of material in such a way that, within the resultant aperture, a lowered region may be formed, delimited laterally by the walls of the aperture and below by the surface of the construction platform (6). A first layer of the material to be solidified, with the intended layer thickness, may then be introduced by the application apparatus (7) into the cavity formed by the aperture and the construction platform (6), or into the lowered region, and may optionally be heated by a heating system to a suitable operating temperature, for example 100° C. to 360° C., preferably 120° C. to 200° C. The control unit (3) then controls the deflector device in such a way that the deflected light beam (2) successively impacts all points of the layer, and sinters or melts the material there. A solid basal layer can thus first be formed. In a second step, the construction platform (6) is lowered by an amount corresponding to one layer thickness, and a second layer of material is introduced by the application apparatus (7) into the resultant lowered region within the aperture, and optionally in turn heated by the heating system.
In one embodiment, the control unit (3) may control the deflector device in such a way that the deflected light beam (2) impacts only that region of the layer of material that is adjacent to the inner surface of the aperture, and solidifies the layer of material there by sintering, thus producing a first, annular, wall layer with a wall thickness of about 2 to 10 mm which completely surrounds the remaining pulverulent material of the layer. This part of the control system is therefore a device for producing a container wall which surrounds the object (5) to be formed, simultaneously with the formation of the object in each layer.
Once the construction platform (6) has been lowered by an amount corresponding to the layer thickness of the next layer, and the material has been applied and heated in the same manner as above, the production of the object (5) may then begin. For this, the control unit (3) controls the deflector device in such a way that the deflected light beam (2) impacts those points of the layer which, according to the coordinates stored in the control unit for the object (5) to be produced, are intended to be hardened. The procedure for the other layers is analogous. In the case of the desired production of an annular wall region in the form of a container wall which encloses the object together with the remaining, unsintered material and thus inhibits escape of the material when the construction platform (6) is lowered below the work table, the device is used to sinter an annular wall layer onto the annular wall layer located thereunder for each layer of the object. Production of the wall may be omitted if a replaceable vessel according to EP 1037739, or a fixedly installed container, is used.
After cooling, the object formed may be removed from the apparatus.
The present invention also provides three-dimensional objects or components produced by the processes of the invention.
In one embodiment, the present invention provides a method for the layer-by-layer production of three-dimensional objects using polymer powders, having an average grain size d50 of less than 50 μm, and which powder is non-flowable in accordance with DIN EN ISO 6186 (method A, flow diameter 15 mm). Preference may be given to a polymer powder having a d50 value of less than 35 μm which in accordance with DIN EN ISO 6186 is non-flowable. Particularly preferred here is a polymer powder with a d50 value of less than 20 μm which in accordance with DIN EN ISO 6186 is non-flowable.
The d50 value may be measured using a Malvern Mastersizer 2000 (dry measurement, 20-40 g of powder metered in using Scirocco dry dispersion equipment. The vibratory trough feed rate is 70%, and the dispersing-air pressure lies at 3 bar. The sample measurement time is 5 seconds (5000 individual measurements); refractive index and blue-light value are set at 1.52. Evaluation via Mie theory).
The dimensional accuracy of the three-dimensional objects may be increased through use of a polymer powder which has an ISO 9277 BET surface area of at least 6 m2/g, preferably, at least 8 m2/g, and most preferably, at least 10 m2/g.
The BET surface area for the purposes of the present invention may be measured in accordance with ISO 9277, using a Micromeritics TriStar 3000, by gas adsorption of nitrogen in a discontinuous volumetric process: 7 measurement points at relative pressures P/P0 of between about 0.05 and about 0.20, calibration of the dead space by means of He (99.996%), sample preparation of 1 h at 23° C.+16 h at 80° C. under reduced pressure, specific surface area related to the degassed sample. Evaluation may be conducted by a multi-point determination.
Suitable polymer powders are the thermoplastic and thermoelastic materials listed above.
The operations for producing a polymer powder of the invention are known to the person skilled in the art, and include spray drying, melt spraying, anionic polymerization and cold grinding. One particularly suitable method for producing powders in accordance with the present invention may be via reprecipitation, wherein a polymer is dissolved in a suitable solvent and then crystallized out.
It is assumed that a person skilled in the art may use the above description to its fullest extent even in the absence of any further information. The preferred embodiments and examples are therefore to be interpreted merely as descriptive disclosure, and certainly not as in any way limiting disclosure. Having generally described this invention, a further understanding can be obtained by reference to certain specific examples which are provided herein for purposes of illustration only, and are not intended to be limiting unless otherwise specified.
The examples were conducted in accordance with the description below unless indicated otherwise. The construction chamber was preheated for 180 min to a temperature which was 20° C. below the process temperature. The temperature in the construction chamber was then increased to the process temperature. The temperature distribution in the construction chamber was not always homogeneous, and the temperature measured by means of a pyrometer was therefore defined as construction-chamber/process temperature. Prior to the first exposure to light, 40 layers of powder with a layer thickness in each case of 150 μm were applied. The laser beam (2) from the laser (1) was deflected by means of a scanning system (3) through the lens (8) onto the temperature-controlled and inertized (N2) plane (4) of the construction field. The lens was configured as an F-theta lens system, in order to ensure an extremely homogeneous focus over the entire construction-field plane.
The component to be exposed to light was positioned centrally in the construction field. A square area with edge length 50 mm was melted by means of the laser. The construction platform (6) was then lowered by 0.15 mm, and a fresh powder layer applied at a velocity of 100 mm/s by means of a customary application apparatus or the slider (7) of the invention. The corresponding points are then laser-sintered. The said steps were repeated until a three-dimensional component (5) of height 50 mm was produced. After the exposure to light was concluded, 40 further layers were applied before the heating elements were switched off and the cooling phase initiated. The time needed for each layer during the entire construction process was below 40 seconds.
After a cooling time of at least 12 hours, the component was removed and freed from the adhering powder.
The construction process was carried out in an EOSINT P360 from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The powder was applied with the coating apparatus of the EOSINT P360, as shown in
The construction process was carried out in an EOSINT P380 from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The powder was applied with the coating apparatus of the EOSINT P380, as shown in
The construction process was carried out in a FORMIGA from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The powder was applied with a conventional coating apparatus of the FORMIGA, as shown in FIG. 3A/3B, in accordance with conventional methods. The quality of the applied powder layers was poor. In large regions in the plane of the construction field, too little powder was applied, or none. It was not possible to produce a three-dimensional object. The process temperature was 166° C.
The construction process was carried out in an EOSINT P360 from EOS GmbH. A PP powder with the powder properties shown in Table 3 was processed. The powder was applied with the coating apparatus of the EOSINT P360, as shown in
The construction process was carried out in an EOSINT P360 from EOS GmbH. A PEEK powder with the powder properties shown in Table 4 was processed. The powder was applied with the coating apparatus of the EOSINT P360, as shown in
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The process temperature was 169° C. The powder was applied using an apparatus in which 4 wipers were mounted in series at a distance of 10 mm. The geometry of the individual wipers is shown in FIG. 4A/4B. The recesses were each 10 mm wide. The fraction of the recessed regions was 50%. The apparatus performed a vibratory translational movement with an amplitude of 4 mm and a frequency of 10 Hz, the displacement vector of which was oriented perpendicular to the direction of coating and parallel to the plane of the construction field, thereby ensuring a uniform distribution of the powder. The powder was readily applied. The construction-field plane was coated completely. The exposure parameters were as follows: laser path 36.0 W, scan velocity 2000 mm/s, distance between exposure lines 0.3 mm. The three-dimensional object produced did not have any surface defects.
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The process temperature was 169° C. The powder was applied using an apparatus whose geometry is shown in FIG. 5A/5B. The angle of the peaks of the beads was 90°. The apparatus performed a vibratory translational movement with an amplitude of 1 mm and a frequency of 100 Hz, the displacement vector of which was oriented perpendicular to the direction of coating and parallel to the plane of the construction field. The powder was readily applied. The construction-field plane was coated completely. The exposure parameters were as follows: laser path 36.0 W, scan velocity 2000 mm/s, distance between exposure lines 0.3 mm. The three-dimensional object produced did not have any surface defects.
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The process temperature was 169° C. The powder was applied using an apparatus in which 2 wipers were mounted in series at a distance of 25 mm. Mounted behind the wipers was a steel roller (diameter 25 mm) for smoothing the plane of the construction field. The geometry of the individual wipers is shown in FIG. 6A/6B/6C. The recesses were each 12 mm wide. The fraction of the recessed regions was 55%. The angle of the peaks of the beads was 80°. The apparatus performed a vibratory translational movement with an amplitude of 4 mm and a frequency of 20 Hz, the displacement vector of which is oriented perpendicular to the direction of coating and parallel to the plane of the construction field. The powder was readily applied. The construction-field plane was coated completely. The exposure parameters were as follows: laser path 36.0 W, scan velocity 2000 mm/s, distance between exposure lines 0.3 mm. The three-dimensional object produced did not have any surface defects.
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PA12 powder with the powder properties shown in Table 1 was processed. The process temperature was 169° C. The powder was applied using a comb-like apparatus as shown in FIG. 7A/7B. The apparatus consisted of 10 rows (row spacing 3 mm) of brass bristles (bristle length 20 mm, diameter 1 mm, 60 bristles per 100 mm length). The apparatus performed a vibratory translational movement with an amplitude of 2 mm and a frequency of 100 Hz, the displacement vector of which was oriented perpendicular to the direction of coating and parallel to the plane of the construction field. The powder was readily applied. The construction-field plane was coated completely. The exposure parameters were as follows: laser path 36.0 W, scan velocity 2000 mm/s, distance between exposure lines 0.3 mm. The three-dimensional object produced did not have any surface defects.
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PA6 powder with the powder properties shown in Table 2 was processed. The powder was applied using a comb-like apparatus as shown in FIG. 7A/7B. The apparatus consisted of 8 rows (row spacing 3 mm) of brass bristles (bristle length 20 mm, diameter 1 mm, 60 bristles per 100 mm length). The apparatus performed a vibratory translational movement with an amplitude of 1 mm and a frequency of 200 Hz, the displacement vector of which was oriented perpendicular to the direction of coating and parallel to the plane of the construction field. The powder was readily applied. The construction-field plane was coated completely. The process temperature was 199° C. The exposure parameters were as follows: laser path 36.0 W, scan velocity 2000 minis, distance between exposure lines 0.3 mm. The three-dimensional object produced does not have any surface defects.
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PP powder with the powder properties shown in Table 3 was processed. The process temperature was 123° C. The powder was applied using an apparatus in which 3 wipers were mounted in series at a distance of 20 mm. The geometry of the first two wipers is shown in FIG. 6A/6B/6C. The third wiper was configured in accordance with FIG. 5A/5B. The recesses of the first two wipers were each 12 mm wide. The fraction of the recessed regions was 55%. The angle in the peaks of the beads was 80° in each case. The apparatus performed a vibratory translational movement with an amplitude of 2 mm and a frequency of 50 Hz, the displacement vector of which was oriented perpendicular to the direction of coating and parallel to the plane of the construction field. The powder was readily applied. The construction-field plane was coated completely. The exposure parameters were as follows: laser path 36.0 W, scan velocity 2000 mm/s, distance between exposure lines 0.3 mm. The three-dimensional object produced did not have any surface defects.
The trial was carried out in the construction chamber of an EOSINT P360 from EOS GmbH. A PEEK powder with the powder properties shown in Table 4 was processed. The process temperature was 199° C. The powder was applied using an apparatus in which 3 wipers were mounted in series at a distance of 20 mm. The geometry of the first two wipers is shown in FIG. 6A/6B/6C. The third wiper was configured in accordance with FIG. 5A/5B. The recesses of the first two wipers were each 12 mm wide. The fraction of the recessed regions was 55%. The angle in the peaks of the beads was 80° in each case. The apparatus performed a vibratory translational movement with an amplitude of 5 mm and a frequency of 40 Hz, the displacement vector of which was oriented perpendicular to the direction of coating and parallel to the plane of the construction field. The powder is readily applied. The construction-field plane was coated completely.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2012 200 161.1 | Jan 2012 | DE | national |
