3D printing method and apparatus

1. A printing apparatus for printing a three-dimensional object, comprising:

an operative surface;

an energy source for emitting at least one energy beam onto the operative surface; and

a powder dispensing mechanism comprising a plurality of supply hoppers and a supply controller, the plurality of supply hoppers and the supply controller being configured to dispense powder adapted to be melted by the energy source from each of the plurality of supply hoppers onto the operative surface to form a plurality of layers of powder of the single three-dimensional object simultaneously;

wherein in use the plurality of supply hoppers are configured to move relative to the operative surface while dispensing the powder;

wherein each layer in the plurality of layers of powder is dispensed onto a subjacent layer in the plurality of layers of powder or, for a bottommost layer in the plurality of layers of powder, the operative surface;

wherein the plurality of layers of powder are formed in a staggered manner such that, when being worked on by the at least one energy beam, each layer in the plurality of layers of powder has an exposed topmost surface section that is not covered by an overlying layer of powder;

wherein the energy source is configured to emit the at least one energy beam onto each of the exposed topmost surface sections simultaneously or sequentially; and

wherein the energy source is configured to be re-oriented to direct the at least one energy beam onto different layers among the plurality of layers.

2. The printing apparatus according to claim 1 , wherein the printing apparatus further comprises an energy beam splitter configured for splitting and directing an energy beam into two or more separate energy beams.

3. The printing apparatus according to claim 1 , wherein the plurality of supply hoppers and the supply controller are configured to deposit the plurality of layers of powder onto the operative surface in a curved path.

4. The printing apparatus according to claim 1 , wherein the powder dispensing mechanism dispenses powder onto a heap on the operative surface in a manner such that the plurality of layers of powder are a plurality of cascading layers of powder that flow simultaneously over an external surface of the heap, each layer in the plurality of cascading layers of powder having an exposed surface that is, at least in part, not covered by a superjacent layer in the plurality of cascading layers of powder while the layer is being formed.

5. The printing apparatus according to claim 4 , wherein the energy source emits energy beams onto two or more layers in the plurality of cascading layers of powder on the heap simultaneously.

6. The printing apparatus according to claim 4 , wherein the energy source emits energy beams onto individual layers in the plurality of cascading layers of powder on the heap in a sequence.

7. The printing apparatus according to claim 4 , wherein the printing apparatus further comprises a scanner for determining a position, velocity and/or size of one or more particles comprised in the powder when the, or each, particle is travelling from one or each of the supply hoppers to the heap.

8. The printing apparatus according to claim 7 , wherein the scanner is adapted to measure an airborne density of the powder travelling to the heap.

9. The printing apparatus according to claim 7 , wherein the scanner is adapted to measure a volume of powder deposited on the heap.

10. The printing apparatus according to claim 7 , wherein the scanner is adapted to measure a shape or profile of the heap.

11. The printing apparatus according to claim 7 , wherein the scanner is adapted to measure a shape, form, relative position or one or more surface characteristics of the plurality of cascading layers of powder formed on the external surface of the heap.

12. The printing apparatus according to claim 1 , wherein the energy source is configured to emit a laser beam.

13. The printing apparatus according to claim 1 , wherein the energy source is configured to emit a collimated light beam.

14. The printing apparatus according to claim 1 , wherein the energy source is configured to emit a micro-plasma welding arc.

15. The printing apparatus according to claim 1 , wherein the energy source is configured to emit an electron beam.

16. A printing apparatus for printing a three-dimensional object, comprising:

an operative surface;

an energy source for emitting at least one energy beam onto the operative surface; and

a powder dispensing mechanism comprising a plurality of supply hoppers and a supply controller, the plurality of supply hoppers and the supply controller being configured to dispense powder in a curved path, wherein in use the plurality of supply hoppers are configured to move relative to the operative surface while dispensing the powder, and wherein the powder is adapted to be melted by the energy source from each of the plurality of supply hoppers onto the operative surface to form a plurality of layers of powder of the single three-dimensional object simultaneously;

wherein each layer in the plurality of layers of powder is dispensed onto a subjacent layer in the plurality of layers of powder or, for a bottommost layer in the plurality of layers of powder, the operative surface;

wherein the plurality of layers of powder are formed in a staggered manner such that, when being worked on by the at least one energy beam, each layer in the plurality of layers of powder has an exposed topmost surface section that is not covered by an overlying layer of powder;

wherein the energy source is configured to emit the at least one energy beam onto each of the exposed topmost surface sections simultaneously or sequentially; and

wherein the energy source is configured to be re-oriented to direct the at least one energy beam onto different layers among the plurality of layers.

17. A method for printing a three-dimensional object using a printing apparatus, the printing apparatus comprising an operative surface, an energy source configured to emit at least one energy beam, and a powder dispensing mechanism comprising a plurality of supply hoppers and a supply controller, the method comprising the steps of:

depositing a plurality of layers of powder of the single three-dimensional object simultaneously onto the operative surface using the plurality of supply hoppers and the supply controller such that each layer in the plurality of layers of powder is dispensed onto a subjacent layer in the plurality of layers of powder or, for a bottommost layer in the plurality of layers of powder, the operative surface, wherein in use the plurality of supply hoppers are configured to move relative to the operative surface while dispensing the powder, and wherein the plurality of layers of powder are formed in a staggered manner such that, when being worked on by the at least one energy beam, each layer in the plurality of layers of powder has an exposed topmost surface section that is not covered by an overlying layer of powder;

using the energy source to emit the at least one energy beam onto each of the exposed topmost surface sections simultaneously or sequentially to melt one or more of the plurality of layers of powder and form part of the single three-dimensional object, wherein the energy source is re-oriented to direct the at least one energy beam onto different layers among the plurality of layers; and

repeating the steps above until the single three-dimensional object is completely formed.

18. A method for printing a three-dimensional object, the method comprising the step of:

(a) providing a printing apparatus for printing the single three-dimensional object, the printing apparatus comprising an operative surface, an energy source for emitting at least one energy beam onto the operative surface, and a powder dispensing mechanism comprising a plurality of supply hoppers and a supply controller, the plurality of supply hoppers and the supply controller being configured for depositing a plurality of layers of powder adapted to be melted by the energy source from each of the plurality of supply hoppers onto the operative surface to form a plurality of layers of powder of the single three-dimensional object simultaneously, wherein each layer in the plurality of layers of powder is dispensed onto a subjacent layer in the plurality of layers of powder or, for a bottommost layer in the plurality of layers of powder, the operative surface, wherein in use the plurality of supply hoppers are configured to move relative to the operative surface while dispensing the powder, and wherein the plurality of layers of powder are formed in a staggered manner such that, when being worked on by the at least one energy beam, each layer in the plurality of layers of powder has an exposed topmost surface section that is not covered by an overlying layer of powder; and wherein the energy source is configured to emit the at least one energy beam onto each of the exposed surface sections simultaneously or sequentially;

wherein the method further comprises the steps of:

(b) depositing the plurality of layers of powder simultaneously onto the operative surface such that each layer in the plurality of layers of powder is dispensed onto a subjacent layer in the plurality of layers of powder or, for the bottommost layer in the plurality of layers of powder, the operative surface;

(c) forming the plurality of layers of powder in the staggered manner such that, when being worked on by the at least one energy beam, each layer in the plurality of layers of powder has the exposed topmost surface section that is not covered by the overlying layer of powder;

(d) using the energy source to emit the at least one energy beam onto each of the exposed topmost surface sections simultaneously or sequentially to melt the powder and form part of the single three-dimensional object, wherein the energy source is re-oriented to direct the at least one energy beam onto different layers among the plurality of layers; and

(e) repeating steps (b)-(d) until the single three-dimensional object is completely formed.