阅读说明：本技术 用于零件的增材铸造的装置和方法 (Apparatus and method for additive casting of parts ) 是由 吉尔·拉维 博阿兹·维诺格拉多夫 于 2018-09-06 设计创作，主要内容包括：公开了用于零件的增材铸造的方法和设备。该方法可包括：在构建台上沉积模具的第一部分,使得沉积可以逐层进行；将液体物质浇注至模具的第一部分中以形成第一铸造层；凝固第一铸造层的至少一部分；在模具的第一部分的顶部上沉积模具的第二部分；将液体物质浇注至模具的第二部分中,以在第一铸造层的至少一部分的顶部上形成第二铸造层；以及凝固第二铸造层的至少一部分。该方法可以进一步包括在浇注第三铸造层之前接合第一铸造层和第二铸造层。(Methods and apparatus for additive casting of parts are disclosed. The method can comprise the following steps: depositing a first portion of the mold on the build table such that the deposition can occur layer by layer; pouring a liquid substance into a first portion of a mold to form a first casting layer; solidifying at least a portion of the first cast layer; depositing a second portion of the mold on top of the first portion of the mold; pouring a liquid substance into a second portion of the mold to form a second casting layer on top of at least a portion of the first casting layer; and solidifying at least a portion of the second cast layer. The method may further include joining the first casting layer and the second casting layer prior to pouring the third casting layer.)

1. A method of additive casting of a part, comprising:

depositing a first portion of a mold on a build station, wherein the depositing is layer-by-layer;

pouring a liquid substance into the first portion of the mold to form a first casting layer;

solidifying at least a portion of the first cast layer;

depositing a second portion of the mold on top of the first portion of the mold;

pouring the liquid substance into the second portion of the mold to form a second casting layer on top of at least a portion of the first casting layer; and

solidifying at least a portion of the second cast layer.

2. The method of claim 1, further comprising: a three-dimensional (3D) part model including one or more parts is received, the part model divided into a plurality of casting layers.

3. The method of claim 2, further comprising:

receiving a 3D mold model, the mold model divided into a plurality of mold portions, wherein the mold model is designed to provide a desired shape for the liquid substance.

4. The method of claim 2, further comprising:

generating a 3D mold model based on the received part model, the mold model being divided into a plurality of mold portions, wherein the mold model is designed to provide a designed shape for the liquid substance.

5. The method according to any one of the preceding claims, wherein the liquid substance is one of the following: molten metal, molten glass, and polymer resin.

6. The method of any of the preceding claims, further comprising:

the first casting layer and the second casting layer are joined prior to the pouring of the third casting layer.

7. The method of claim 6, wherein joining comprises melting at least a portion of an interface between the first and second cast layers.

8. The method of claim 6 or claim 7, wherein joining comprises treating at least a portion of an upper surface of the second casting layer with at least one of: induction heaters, resistance welders, ultrasonic welders, plasma deposition units, electron beams, lasers, welding arcs, welding torches, cold melting, and magnetic field flow.

9. The method of claim 6, wherein engaging comprises at least one of: gluing, ultrasonic bonding, diffusion bonding, thermal curing, and Ultraviolet (UV) curing.

10. The method of any preceding claim, further comprising: each casting layer is preheated prior to the pouring of the additional casting layer.

11. The method of any preceding claim, further comprising: after solidification and before the pouring of the additional casting layer, each casting layer is provided with a surface treatment.

12. The method of claim 11, wherein the surface treatment comprises at least one of: machining, grinding, polishing, and laser ablation.

13. The method according to any of the preceding claims, further comprising: the inner wall of each mould section is provided with a surface treatment prior to pouring the corresponding casting layer.

14. The method of claim 12, wherein the surface treatment of the inner wall of each mold section comprises machining the inner wall and removing excess material.

15. The method of any preceding claim, further comprising flattening the first casting layer and the first mold portion to the same level prior to deposition of the second mold portion.

16. The method according to any one of the preceding claims, wherein the depositing and casting steps are performed under a protective atmosphere.

17. The method of any preceding claim, wherein the first and second cast layers have different thicknesses.

18. The method according to any one of the preceding claims, wherein the first and second cast layers have a thickness between 0.1mm-12 mm.

19. The method of any preceding claim, wherein each mould layer comprises a mixture of particulate material and a binder, wherein the particulate material may comprise at least one of: ceramic powder, sand, clay, and any combination thereof.

20. The method of claim 19, wherein the mixture further comprises a metal powder.

21. The method of any preceding claim, wherein depositing one or more mold layers comprises printing each mold layer using a 3D printer.

22. The method according to any one of the preceding claims, wherein the liquid substance is poured from a movable pouring unit comprising at least one liquid introduction port for pouring the liquid substance.

23. The method of claim 16, wherein the movable casting unit is configured to cast a predetermined amount of liquid substance at a predetermined location in each mold portion.

24. The method of any preceding claim, further comprising annealing the solidified first casting layer by pouring molten metal to form a third casting layer and a fourth casting layer.

25. The method of any preceding claim, wherein:

casting the first casting layer by pouring a first liquid substance having a first chemical composition; and casting the second casting layer by pouring a second liquid substance having a second chemical composition.

26. The method of claim 25, wherein the first and second liquid substances are selected from the group consisting of: two alloys of the same metal element, two types of glass, and two types of polymer.

27. A method according to claim 25 or claim 26, wherein the first and second liquid substances differ in at least one of: an amount and a type of additive, wherein the additive is configured to evaporate and decompose at least during casting.

28. The method of any of the preceding claims, further comprising:

measuring a chemical composition of a liquid substance in the first container prior to pouring the liquid substance into at least one of the first and second mold portions;

measuring the chemical composition of the corresponding cast layer; and

the measurements are compared.

29. The method of claim 28, further comprising:

removing the corresponding cast layer if the difference in chemical composition resulting from the measurement is greater than a threshold value; and

pouring a new liquid substance into at least one of the first and second mould parts.

30. The method of any preceding claim, wherein the liquid substance is poured into the second mould part in an amount sufficient to form the second casting layer and compensate for at least one of: shrinkage of the first cast layer and thickness variation in the first cast layer.

31. An additive casting apparatus comprising: a movable dispensing unit in fluid connection with a first container containing a mold material, the dispensing unit comprising one or more liquid introduction ports for depositing the mold material;

a movable pouring unit in fluid connection with at least one second container for storing liquid substances, the pouring unit comprising one or more liquid introduction ports for pouring at least one liquid substance;

a build station for storing deposited mold material and poured liquid material; and

a controller configured to:

controlling the movable dispensing unit to deposit a first portion of a mold layer by layer;

controlling the movable pouring unit to pour at least one liquid substance into the first portion of the mold to form a first cast layer;

controlling the movable dispensing unit to deposit a first portion of a mold layer by layer onto a top of the first portion; and

controlling the movable pouring unit to pour at least one liquid substance into the second portion of the mold to form a second cast layer on top of at least a portion of the first cast layer.

32. The additive casting apparatus of claim 31, further comprising:

a joining unit configured to join the first and second casting layers prior to deposition of the third mold portion and pouring of the third casting layer.

33. The additive casting apparatus of claim 32, wherein the engagement unit is at least one of: induction heaters, electron beams, resistance welders, arc welders, laser welders, welding torches, gluing devices, cold melt units, magnets for magnetic field flow, ultrasonic bonding units, and heaters for diffusion bonding.

34. Additive casting apparatus according to any one of the preceding claims, wherein the at least one second container is a crucible and the liquid substance is one of molten metal and molten glass.

35. An additive casting apparatus according to any one of claims 31 to 33, wherein the at least one second vessel is a tank and the liquid substance is at least one of a polymer resin or a molten polymer.

36. Additive casting device according to any one of the preceding claims, further comprising a preheating unit for heating each casting layer before pouring additional casting layers.

37. The additive casting apparatus of any one of the preceding claims, further comprising:

one or more surface treatment units for treating the surface of each casting layer after solidification and before pouring the additional casting layer.

38. The additive casting apparatus of claim 26, wherein the one or more surface treatment units comprise at least one of: a machining device, a grinding device and a polishing device.

39. The additive casting apparatus of any one of the preceding claims, further comprising:

a periphery filled with a protective atmosphere for providing the protective atmosphere to the cast layer during casting.

40. The additive casting apparatus of claim 39, wherein the enclosure comprises a closed housing containing: the movable distribution unit, the movable casting unit, the build station and an apparatus configured to provide the protective atmosphere.

41. The additive casting apparatus of any one of the preceding claims, wherein the controller is further configured to:

receiving a three-dimensional (3D) part model of one or more solid parts, the 3D part model divided into a plurality of casting layers;

receiving a 3D mold model of a mold, the mold model divided into a plurality of mold portions, wherein the mold is designed to provide a liquid substance with a desired shape;

controlling deposition of the mold portions based on the mold model; and

controlling pouring of the casting layer based on the part model.

42. Additive casting apparatus according to any one of the preceding claims, wherein the movable deposition unit is configured to move in at least one axis.

43. An additive casting apparatus according to any one of the preceding claims, wherein the movable casting unit is configured to move in at least one axis.

44. Additive casting apparatus according to any one of the preceding claims, wherein the build table is coupled to a movable platform.

45. Additive casting apparatus according to any one of the preceding claims, wherein the movable pouring unit is in fluid connection with two containers for storing a first liquid substance and a second liquid substance,

and wherein the controller is configured to:

controlling the movable pouring unit to pour the first liquid substance into the first portion of the mold to form a first cast layer; and

controlling the movable pouring unit to pour the second liquid substance into the second portion of the mold to form a second cast layer.

46. The additive casting apparatus of any one of the preceding claims, further comprising:

at least one chemical composition sensor configured to measure at least: the chemical composition of the liquid substance in the container and the chemical composition of the casting layer.

47. The additive casting apparatus of claim 45, wherein the at least one substance composition sensor is based on X-rays or laser light.

48. A cast metal part comprising:

at least a first casting layer comprising a first type of alloy;

at least a second casting layer comprising a second type of alloy, the at least second casting layer being bonded to the at least first casting layer,

wherein the first alloy and the second alloy are different alloys of the same metal element.

49. The cast metal part of claim 48, wherein the thickness of each cast layer is at least two orders of magnitude less than the perimeter of each cast layer.

50. The cast metal part of claim 48 or claim 49, further comprising a third casting layer joined to at least one second casting layer.

51. The cast metal part of claim 50, wherein the third casting layer comprises a third type alloy of the same metallic element.

52. The cast metal part of any of claims 48-51, wherein the at least first and second casting layers are further microstructurally different.

53. A cast metal part comprising:

at least a first casting layer having a first predetermined microstructure;

at least a second casting layer having a second predetermined microstructure, the at least second casting layer being bonded to the at least first casting layer,

wherein the first predetermined microstructure and the second predetermined microstructure differ in at least an average grain size.

54. The cast metal part of claim 53, wherein the thickness of each cast layer is at least two orders of magnitude less than the perimeter of each cast layer.

55. The cast metal part of claim 53 or claim 54, further comprising a third casting layer joined to at least one second casting layer.

56. The cast metal part of claim 55, wherein the third casting layer has a third predetermined microstructure.

Background

Casting is one of the oldest material forming methods still in use to date. The idea of pouring a liquid material into a mould containing a hollow cavity of the desired shape and then letting it solidify has been known for 6000 years. The main process was unchanged since 3200 years before the year of the notarization bronze was melted and poured into stone molds. When the glass was invented about 3000 years ago, the glass was also cast in a mold (in addition to the glass blowing process) to form an article made of glass. In modern times, polymer resins are also cast into molds to form shaped polymer parts.

Modern casting methods involve the use of molds made of various materials, such as sand casting, die casting (e.g., metal molds), half die casting (e.g., metal molds + sand inserts), investment casting (e.g., ceramic shell molds), lost foam casting (e.g., replicating a polymer foam with a molten metal placed in a sand container), and the like. However, the idea of pouring all the required amounts of metal in a single pouring action to form the desired object/part is not changed.

Casting, while a very reliable method, is also very expensive, time consuming, and suitable for mass production. The time required to form a die casting mold or to make a mold for sand casting molds is typically several months. Furthermore, even the most modern casting methods do not adapt to the variations. Each minor change in the mold makes the process more expensive and lengthens the production time.

Printing three-dimensional (3D) objects is one of the latest material forming methods. Inks made of polymeric resins, metal powders mixed with binders, or ceramic powders mixed with binders are printed on the build table, sometimes with the addition of a print housing/support structure to support the printed object. The 3D computerized model is used to create a printed object. Thus, any change in the 3D model is easily accomplished without the need to change any printing parameters. However, the quality of printed parts (e.g., mechanical properties, material defects, voids, and dislocations), particularly metallic printed parts that also require heat treatment processes, is generally lower than the quality of cast parts.

Current processes for three-dimensional printing of metal objects include layer-by-layer deposition of metal powders/particles followed by selective laser sintering (S L S) to melt/solidify the finely deposited layer Another process includes printing a wax pattern of a mold by a three-dimensional printer for subsequent manufacture of the metal object in investment casting.

Therefore, there is a need for a system and method that eliminates the disadvantages of the production methods described above.

Summary of The Invention

Some aspects of the invention may be directed to a method of additive casting of a part. In some embodiments, the method may comprise: depositing a first portion of the mold on the build table such that the deposition occurs layer by layer; pouring a liquid substance into a first portion of a mold to form a first casting layer; solidifying at least a portion of the first cast layer; depositing a second portion of the mold on top of the first portion of the mold; pouring a liquid substance into a second portion of the mold to form a second casting layer on top of at least a portion of the first casting layer; and solidifying at least a portion of the second cast layer.

In some embodiments, the method may further include receiving a three-dimensional (3D) part model including one or more parts, the part model divided into a plurality of casting layers. In some embodiments, the method may further include receiving a 3D mold model, the mold model divided into a plurality of mold portions, wherein the mold model is designed to provide a liquid substance with a desired shape. In some embodiments, the method may further include generating a 3D mold model based on the received part model, the mold model being divided into a plurality of mold portions, wherein the mold model is designed to provide the designed shape for the liquid substance.

In some embodiments, the liquid substance is one of: molten metal, molten glass, and polymer resin. In some embodiments, the method may further comprise joining the first casting layer and the second casting layer prior to pouring of the third casting layer. In some embodiments, joining may include melting at least a portion of an interface between the first and second cast layers. In some embodiments, joining may include treating at least a portion of the upper surface of the second casting layer with at least one of: induction heaters, resistance welders, ultrasonic welders, plasma deposition units, electron beams, lasers, welding arcs, welding torches, cold melting, and magnetic field flow. In some embodiments, the engaging may comprise at least one of: gluing, ultrasonic bonding, diffusion bonding, thermal curing, and Ultraviolet (UV) curing.

In some embodiments, the method may further comprise preheating each casting layer prior to pouring of the additional casting layer. In some embodiments, the method may further comprise providing a surface treatment to each cast layer after solidification and prior to pouring of the additional cast layer. In some embodiments, the surface treatment may include at least one of: machining, grinding, polishing, and laser ablation. In some embodiments, the method may further comprise: the inner wall of each mould section is provided with a surface treatment prior to the pouring of the corresponding casting layer. In some embodiments, the surface treatment of the inner wall of each mold section may include machining the inner wall and removing excess material.

In some embodiments, the method may further comprise flattening the first casting layer and the first mold portion to the same level prior to deposition of the second mold portion. In some embodiments, the depositing and casting steps are performed under a protective atmosphere. In some embodiments, the first and second cast layers have different thicknesses. In some embodiments, the first and second cast layers have a thickness between 0.1mm-12 mm. In some embodiments, each mold layer may include a mixture of a granular material and a binder, wherein the granular material may include at least one of: ceramic powder, sand, clay, and any combination thereof. In some embodiments, the mixture may also include a metal powder.

In some embodiments, depositing one or more mold layers may include printing each mold layer using a 3D printer. In some embodiments, the liquid substance is poured from a movable pouring unit that includes at least one liquid introduction port for pouring the liquid substance. In some embodiments, the movable pouring unit may be configured to pour a predetermined amount of liquid substance at a predetermined location in each mold portion. In some embodiments, the method may further include annealing the solidified first casting layer by pouring molten metal to form a third casting layer and a fourth casting layer. In some embodiments, the first casting layer is cast by pouring a first liquid substance having a first chemical composition; and casting the second casting layer by casting a second liquid substance having a second chemical composition. In some embodiments, the first liquid substance and the second liquid substance may be selected from: two alloys of the same metal element, two types of glass, and two types of polymer.

In some embodiments, the first liquid substance and the second liquid substance differ in at least one of: an amount and a type of additive, wherein the additive is configured to at least: evaporate and decompose during casting. In some embodiments, the method may further comprise: measuring a chemical composition of the liquid substance in the first container prior to pouring the liquid substance into at least one of the first and second mold portions; measuring the chemical composition of the corresponding cast layer; and comparing the measurements (measures). In some embodiments, the method may further comprise: removing the corresponding cast layer if the difference in chemical composition resulting from the measurement is greater than a threshold value; and pouring a new liquid substance into at least one of the first and second mould parts.

In some embodiments, the amount of liquid substance poured into the second mold portion may be sufficient to form the second casting layer and compensate for at least one of: shrinkage of the first cast layer and thickness deviation of the first cast layer.

Aspects of the invention may relate to an additive casting apparatus. An additive casting apparatus according to an embodiment of the present invention may include: a movable dispensing unit in fluid connection with a first container containing a mold material, the dispensing unit comprising one or more liquid introduction ports for depositing the mold material; a movable pouring unit in fluid connection with at least one second container for storing liquid substances, the pouring unit comprising one or more liquid introduction ports for pouring at least one liquid substance; a build station for storing deposited mold material and poured liquid material; and a controller configured to: controlling a movable dispensing unit to deposit a first portion of a mold layer by layer; controlling a movable pouring unit to pour at least one liquid substance into the first mould part to form a first cast layer; controlling a movable dispensing unit to deposit a first portion of a mold layer by layer onto a top of the first portion; and controlling the movable pouring unit to pour the at least one liquid substance into the second portion of the mold to form a second cast layer on top of at least a portion of the first cast layer.

In some embodiments, the additive casting apparatus may further comprise a joining unit configured to join the first and second casting layers prior to deposition of the third mold portion and pouring of the third casting layer. In some embodiments, the engagement unit may be at least one of: induction heaters, electron beams, resistance welders, arc welders, laser welders, welding torches, gluing devices, cold melt units, magnets for magnetic field flow, ultrasonic bonding units, and diffusion bonding heaters. In some embodiments, the at least one second container may be a crucible and the liquid substance is one of molten metal and molten glass. In some embodiments, the at least one second container may be a tank and the liquid substance is at least one of a polymer resin or a molten polymer.

In some embodiments, the additive casting apparatus may further comprise a preheating unit for heating each casting layer prior to pouring the additional casting layer. In some embodiments, the additive casting apparatus may further comprise one or more surface treatment units for treating the surface of each casting layer after solidification and before pouring the additional casting layer. In some embodiments, the one or more surface treatment units comprise at least one of: a machining device, a grinding device and a polishing device.

In some embodiments, the additive casting apparatus may further comprise a periphery filled with a protective atmosphere for providing a protective atmosphere to the cast layer during casting. In some embodiments, the enclosure may include a closed housing containing: a movable distribution unit, a movable casting unit, a build station, and an apparatus configured to provide a protective atmosphere. In some embodiments, the controller may be further configured to: receiving a three-dimensional (3D) part model of one or more solid parts, the 3D part model divided into a plurality of casting layers; receiving a 3D mold model of a mold, the mold model divided into a plurality of mold portions, wherein the mold is designed to provide a liquid substance with a desired shape; controlling deposition of the mold sections based on the mold model; and controlling the pouring of the casting layer based on the part model.

In some embodiments, the movable deposition unit is configured to move in at least one axis (axe). In some embodiments, the movable casting unit is configured to move in at least one axis. In some embodiments, the additive casting apparatus may further comprise a build station, which may be coupled to the movable platform. In some embodiments, the movable pouring unit may be fluidly connected to two containers for storing the first liquid substance and the second liquid substance, and the controller may be configured to: controlling a movable pouring unit to pour a first liquid substance into a first portion of a mold to form a first casting layer; and controlling the movable pouring unit to pour a second liquid substance into a second portion of the mold to form a second cast layer.

In some embodiments, the additive casting apparatus may further comprise at least one chemical composition sensor configured to measure at least: the chemical composition of the liquid substance in the container and the chemical composition of the casting layer. In some embodiments, the at least one material composition sensor is based on X-rays or laser light.

Some additional aspects of the present invention may be directed to a cast metal part, which may include: at least a first casting layer comprising a first type of alloy; at least a second casting layer comprising a second type of alloy, the second casting layer bonded to the at least a first casting layer. In some embodiments, the first alloy and the second alloy are different alloys of the same metallic element. In some embodiments, the thickness of each cast layer may be at least two orders of magnitude less than the perimeter of each cast layer. In some embodiments, the cast metal part may further include a third casting layer joined to the at least one second casting layer. In some embodiments, the third casting layer may comprise a third type of alloy of the same metallic element. In some embodiments, at least a first casting layer may also be microstructurally different from at least a second casting layer.

Some additional aspects of the present invention may be directed to a cast metal part, which may include: at least a first casting layer having a first predetermined microstructure; and at least a second casting layer having a second predetermined microstructure, the at least second casting layer being bonded to the at least first casting layer. In some embodiments, the first predetermined microstructure and the second predetermined microstructure may differ in at least an average grain size (average grain size). In some embodiments, the thickness of each cast layer may be at least two orders of magnitude less than the perimeter of each cast layer. In some embodiments, the cast metal part may further include a third casting layer joined to the at least one second casting layer. In some embodiments, the third casting layer has a third predetermined microstructure.