Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C64/00—Additive manufacturing, i.e. manufacturing of three-dimensional [3D] objects by additive deposition, additive agglomeration or additive layering, e.g. by 3D printing, stereolithography or selective laser sintering
  • B29C64/10—Processes of additive manufacturing
  • B29C64/141—Processes of additive manufacturing using only solid materials
  • B29C64/153—Processes of additive manufacturing using only solid materials using layers of powder being selectively joined, e.g. by selective laser sintering or melting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3-D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3-D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y10/00—Processes of additive manufacturing
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/30—Process control
  • B22F10/36—Process control of energy beam parameters
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F12/00—Apparatus or devices specially adapted for additive manufacturing; Auxiliary means for additive manufacturing; Combinations of additive manufacturing apparatus or devices with other processing apparatus or devices
  • B22F12/60—Planarisation devices; Compression devices
  • B22F12/63—Rollers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
  • B22F3/10—Sintering only
  • B22F3/1017—Multiple heating or additional steps
  • B22F3/1028—Controlled cooling
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• This invention relates to an additive manufacturing method and to a product manufactured thereby.
• a number of additive manufacturing processes are known. For example, one technique involves depositing a thin layer of material, in powder form, upon a support table and selectively fusing the parts of the layer which are to form part of the product. Subsequently, a further layer of material is deposited upon the previously deposited layer and the fusing process is repeated. These steps are repeated a number of times until a desired product has been formed.
• the material used can include a range of polymer materials, metals, graphite and wax-like materials.
• an additive manufacturing method comprising depositing a product material to form a first product layer, undertaking a fusing operation to form reinforcing regions within the first product layer, and depositing and undertaking a fusing operation on at least one further product layer to form a multilayered product integrally formed with reinforcing regions.
• the reinforcing regions of adjacent layers may be bonded or fused to one another.
• the product material may be of a type in which heating thereof to a first temperature, and subsequent cooling, results in the formation of regions of the layer with a first structure, and heating thereof to a second, higher temperature, and subsequent cooling thereof, results in the formation of regions of the layer with a second structure.
• the first and second structures may comprise different crystal structures and/or different super molecular orders.
• the first and second structures may both comprise crystalline or semicrystalline structures or, alternatively, the first structure may be amorphous whilst the second structure is crystalline or semicrystalline. It will be appreciated that by appropriate control over the melting or sintering operations, the temperatures to which various of parts of the layer are exposed can be controlled with the result that material with the first structure is present in some parts of the layer whilst material with the second structure is present elsewhere.
• Material of one of the first and second structures may form the majority of the material of the final product, the material of the other of the structures forming reinforcing regions extending within the material. If desired, the reinforcing regions formed in one of the layers may bond with the reinforcing regions of adjacent layers, thereby strengthening the bond between the adjacent layers, and so enhancing the strength of the overall product.
• the reinforcing regions may be formed where desired within the product, thus some parts of the product may, if desired, contain more reinforcing regions that other. Furthermore, the directions in which the reinforcement formed by the reinforcing regions extends may be controlled as desired.
• the product material may comprise a substantially uniform blend of a material with a relatively high melting point and a material with a relatively low melting point, the fusing operation heating the product material to a temperature sufficiently high to cause melting of the low melting point material but low enough to cause sintering or fusing of the high melting point material, but avoiding complete melting thereof.
• the lower melting point material within a matrix of higher melting point material serves to reinforce the higher melting point material, thus forming reinforcing regions within the product.
• the materials are preferably polymers, conveniently selected from the same polymer family, for example they may be selected from PEK, PEEK and PEKK (all poly aryl ether ketones) or from PA6, PA6.6, PA12 or PA11 (all polyamides).
• the blend may comprise a blend of PEEK and PEK.
• the PEK forms the relatively high melting point material, having a melting point of 365°C
• the PEEK with a melting point of 335°C forming the relatively low melting point material.
• the additive manufacturing process is conveniently a powder bed process. However, this need not always be the case and the invention may also applicable to arrangements in which other additive manufacturing processes are used.
• Figure 1 illustrates the manufacture of a product in accordance with one embodiment of the invention
• Figures 2 and 3 illustrate variants to the arrangement of Figure 1 ;
• Figure 4 is a view illustrating an alternative arrangement
• Figure 5 is a graph illustrating the effect of increasing heating.
• a powder bed type additive manufacturing apparatus comprises a support table 20 which is capable of being incrementally raised and lowered.
• a delivery device 30 is arranged to deliver uniform thickness layers 5a, 5b of powder material to the table 20, when desired, the thickness of each layer 5a, 5b being determined by the size of the increments by which the table 20 can be lowered.
• a laser-based heating device 40 is operable to heat the material of the layers 5a, 5b. The heating operation is undertaken by scanning the laser beam output from the device 40 over selected parts of each layer 5a, 5b to raise the temperature of the selected parts of each layer 5a, 5b.
• the manner in which the laser beam output is scanned could involve physically moving the laser relative to the table 20. However, it will generally be more convenient for the laser and table 20 to both be fixed during the scanning operation, and for the laser beam output to be scanned over the layers 5a, 5b by adjustment of the positions of suitable optical devices such as mirrors or other reflectors.
• the device 40 is conveniently computer controlled, both in relation to the selection of which parts of each layer to heat and in relation to the temperature to heat each region to. Conveniently, a single computer program undertakes all of this control.
• Figure 5 illustrates that the use of increased laser power (and hence increased temperature if the other parameters are held constant) results in the formation of materials of enhanced resilience, being capable of withstanding increased loads, and hence undergoing increased elongation, prior to failure.
• the powder material is nylon
• the process may result in the formation of, for example, regions 15a of nylon-6 and regions 10a of nylon-6,6.
• the reinforcing regions 15 each extend perpendicularly to the table 20, this need not always be the case.
• the reinforcing regions 15 may be angled relative to the table (for example as shown in Figure 2), or may extend parallel to the table 20 (for example as shown in Figure 3). It will be appreciated that these options are merely examples and that a wide range of alternatives are possible without departing from the scope of the invention.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)

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Cited By (14)

Citations (5)

• 2013
  • 2013-03-18 WO PCT/GB2013/050687 patent/WO2013136096A1/fr not_active Ceased

Patent Citations (5)

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