Additive manufacturing apparatus and methods

Patent metadata

Field	Value
Publication number	US-10933620-B2
Application number	US-201515528701-A
Country	US
Kind code	B2
Filing date	Nov 17, 2015
Priority date	Nov 21, 2014
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

This invention concerns an additive manufacturing apparatus for building a part by selectively consolidating flowable material in a layer-by-layer process comprising a build chamber (101) for building the part, a module (105, 106) for providing a focussed energy beam for consolidating flowable material in the build chamber, a gas flow circuit for generating a gas flow through the build chamber (101). At least one filter assembly (200, 201) may be arranged in the gas flow circuit, the or each filter assembly (200, 201) having associated therewith a valve (V-4, V-8) operable to seal the gas circuit upstream from the filter assembly (200, 201) and a valve (V-5, V-9) operable to seal the gas flow circuit downstream of the filter assembly (200, 201), the arrangement allowing a filter element (E-5, E-7) of the filter assembly (200, 201) to be changed whilst maintaining a controlled atmosphere in the build chamber (101). The apparatus may further comprise a purging device (210) configured to purge air from the or each filter assembly (200, 201) when the valves (V-4, V-5; V-8, V-9) associated with that filter assembly (200, 201) have sealed the filter assembly (200, 201) from the gas flow. Alternatively or additionally, a controller (131) may be arranged to control the valves (V-4, V-5; V-8, V-9) associated with the or each filter assembly (200, 201) such that the filter assemblies (200, 201) are closed off to gas flow from the build chamber (101) during a period in which the inert gas atmosphere in the build chamber (101) is compromised as a result of opening the door to the build chamber (101). The apparatus may comprise a pair of filter assemblies (200, 201) arranged in parallel within the gas flow circuit, the arrangement allowing a filter element (E-5, E-7) of the each filter assembly (200, 201) to be changed during a build by allowing the filter element (E-5, E-7) of one filter assembly (200, 201) to be changed whilst the filter element (E-5, E-7) of the other filter assembly (200, 201) is connected to filter particulates from the gas flow. A monitoring device (I-3, I-5) may be provided for detecting a property associated with the gas flow and a controller (131) arranged to control the valves to switch the filter assembly (200, 201) connected in line with the gas flow based upon signals from the monitoring device (I-3, I-5).

First claim

The invention claimed is:

1. An additive manufacturing apparatus for building a part by selectively consolidating flowable material in a layer-by-layer process, the apparatus comprising:
a build chamber for building the part;
a scanner comprising at least one optical element that is movable to direct a laser beam to consolidate flowable material in the build chamber;
a gas flow circuit for generating a gas flow through the build chamber;
at least one filter assembly arranged in the gas flow circuit, the filter assembly having associated therewith a valve operable to seal the gas circuit upstream from the filter assembly and a valve operable to seal the gas flow circuit downstream of the filter assembly, the arrangement allowing a filter element of the filter assembly to be changed whilst maintaining a controlled atmosphere in the build chamber;
an inlet between the filter element of the filter assembly and one of the valves for introducing inert gas into the filter assembly;
a vent between the filter element and the other of the valves; and
a purging device comprising an inert gas supply, an inert gas supply valve operable to control the flow of inert gas from the inert gas supply to the filter assembly via the inlet and a controller operable to control the inert gas supply valve to open the inert gas supply valve in response to receiving a signal indicating that the filter element has been changed and before the valves associated with the filter assembly are opened to connect the filter assembly in line with the gas flow through the build chamber to flush the filter assembly with an inert gas to push air from the filter assembly out of the vent.

2. An additive manufacturing apparatus according to claim 1 , wherein the inlet and vent are located such that inert gas is flushed through the filter element in an opposite direction to the gas flow when the filter assembly is connected in gaseous communication with the build chamber.

3. An additive manufacturing apparatus according to claim 1 , comprising a first filter assembly and a second filter assembly arranged in parallel within the gas flow circuit, wherein the purging device is arranged to flush one of the first filter assembly and the second filter assembly whilst the other of the first filter assembly and the second filter assembly is connected to filter particulates from the gas flow.

4. An additive manufacturing apparatus according to claim 1 , wherein the purging device further comprises an oxygen sensor for generating a signal indicative of an oxygen content within the filter assembly and the controller is operable to open of the valves associated with the filter assembly to connect the filter assembly in line with the gas flow through the build chamber after the oxygen content detected by the oxygen sensor is below a predetermined level.

5. An additive manufacturing apparatus for building a part by selectively consolidating flowable material in a layer-by-layer process, the apparatus comprising:
a build chamber for building the part;
a scanner comprising at least one optical element that is movable to direct a laser beam to consolidate flowable material in the build chamber;
a gas flow circuit for generating a gas flow through the build chamber;
at least one filter assembly arranged in the gas flow circuit, the filter assembly having associated therewith a valve operable to seal the gas circuit upstream from the filter assembly and a valve operable to seal the gas flow circuit downstream of the filter assembly, the arrangement allowing a filter element of the filter assembly to be changed whilst maintaining a controlled atmosphere in the build chamber; and
a purging device comprising an inert gas supply, an inert gas supply valve operable to control the flow of inert gas from the inert gas supply to the filter assembly, a pump arranged to apply a low pressure or a vacuum pressure to the filter assembly to remove air from the filter assembly when the valves associated with the filter assembly have sealed the filter assembly from the gas flow and a controller operable to control the inert gas supply valve to open the inert gas supply valve in response to receiving a signal indicating that the filter element has been changed and before the valves associated with the filter assembly are opened to connect the filter assembly in line with the gas flow through the build chamber to flood the filter assembly with an inert gas.

6. An additive manufacturing apparatus according to claim 5 , wherein the purging device further comprises an oxygen sensor for generating a signal indicative of an oxygen content within the filter assembly and the controller is operable to open of the valves associated with the filter assembly to connect the filter assembly in line with the gas flow through the build chamber after the oxygen content detected by the oxygen sensor is below a predetermined level.

7. An additive manufacturing apparatus according to claim 5 , comprising a first filter assembly and a second filter assembly arranged in parallel within the gas flow circuit, wherein the purging device is arranged to flush one of the first filter assembly and the second filter assembly whilst the other of the first filter assembly and the second filter assembly is connected to filter particulates from the gas flow.

8. An additive manufacturing apparatus for building a part by selectively consolidating flowable material in a layer-by-layer process, the apparatus comprising:
a build chamber for building the part;
a scanner comprising at least one optical element that is movable to direct a laser beam to consolidate flowable material in the build chamber;
a gas flow circuit for generating a gas flow through the build chamber;
at least one filter assembly arranged in the gas flow circuit, the filter assembly having associated therewith a valve operable to seal the gas circuit upstream from the filter assembly and a valve operable to seal the gas flow circuit downstream of the filter assembly, the arrangement allowing a filter element of the filter assembly to be changed whilst maintaining a controlled atmosphere in the build chamber;
an inlet between the filter element of the filter assembly and one of the valves for introducing inert gas into the filter assembly;
a vent between the filter element and the other of the valves; and
a purging device comprising an inert gas supply, an inert gas supply valve operable to control the flow of inert gas from the inert gas supply to the filter assembly via the inlet and a controller operable to control the inert gas supply valve to open the inert gas supply valve in response to receiving a signal indicating completion of an operation to get rid of reactive particles captured by the filter element and before the valves associated with the filter assembly are opened to connect the filter assembly in line with the gas flow through the build chamber to flush the filter assembly with an inert gas to push air from the filter assembly out of the vent.

9. An additive manufacturing apparatus according to claim 8 , wherein the controller is operable to control the inert gas supply valve such that the filter assembly is flushed with inert gas to remove air from the filter assembly after the air has been introduced into the filter assembly during the operation on the filter element.

10. An additive manufacturing apparatus according to claim 9 , wherein the operation is changing of the filter element.

11. An additive manufacturing apparatus according to claim 8 , wherein the inlet and vent are located such that inert gas is flushed through the filter element in an opposite direction to the gas flow when the filter assembly is connected

Assignees

• Renishaw Plc

Inventors

• Sutcliffe Christopher John
• Joannou Jason
• Dunkley Jack
• Revanur Ramkumar

Classifications

• B22F10/77

  of gas · CPC title

• B22F10/322

  of the gas flow, e.g. rate or direction · CPC title

• B22F12/90

  Means for process control, e.g. cameras or sensors · CPC title

• B22F12/52

  Hoppers · CPC title

• B22F10/28

  Powder bed fusion, e.g. selective laser melting [SLM] or electron beam melting [EBM] · CPC title