Apparatus and methods for building objects by selective solidification of powder material

Patent metadata

Field	Value
Publication number	US-2016193696-A1
Application number	US-201414910399-A
Country	US
Kind code	A1
Filing date	Aug 21, 2014
Priority date	Aug 22, 2013
Publication date	Jul 7, 2016
Grant date	—

Abstract

An additive manufacturing machine for building objects by layerwise melting of powder material includes a build chamber containing a build platform, a powder dispenser depositing the powder material in layers across the platform, a high energy beam selectively melting powder material in each layer and a control device controlling a property of the powder material given by build particles in the powder material below a specified upper particle size limit. A method includes controlling a property of the powder material given by build particles below a specified upper particle size limit. A method carries out successive builds, wherein in-between the builds, particles are added to or removed from the powder material to effect a property of the powder material given by build particles below a specified upper particle size limit. Further, adding or removing particles ensure that a sufficient proportion of micro build particles are present in the powder.

First claim

1 . An additive manufacturing machine for building objects by layerwise melting of powder material, the machine comprising a build chamber containing a build platform, a powder dispenser for depositing the powder material in layers across the build platform, a high energy beam for selectively melting powder material in each layer and a control device for controlling a property of the powder material given by build particles in the powder material that are below an upper particle size limit specified for the build.

2 . An additive manufacturing machine according to claim 1 , wherein the control device is arranged for controlling a particle size distribution of build particles in the powder material

3 . An additive manufacturing machine according to claim 2 , wherein the control device controls a ratio of micro build particles in the powder material, wherein micro build particles are particles having a particle size less than one-quarter of the upper particle size limit.

4 . An additive manufacturing machine according to claim 2 , wherein the control device controls a ratio of micro build particles in the powder material, wherein micro build particles are particles having a particle size less than one-fifth of the upper particle size limit.

5 . An additive manufacturing machine according to claim 2 , wherein the micro build particles are particles having a size less than 10 micrometres.

6 . An additive manufacturing machine according to claim 5 , wherein the micro build particles are particles having a size less than 5 micrometres.

7 . An additive manufacturing machine according to claim 6 , wherein the micro build particles are nanoparticles.

8 . An additive manufacturing machine according to claim 3 , wherein the control device is arranged to change the particle size distribution by adding or removing micro build particles.

9 . An additive manufacturing machine according claim 3 , wherein the control device is arranged to change the particle size distribution by adding or removing macro build particles, wherein macro build particles are particles having a size larger than the micro build particles but below the upper particle size limit.

10 . An additive manufacturing machine according to claim 2 , wherein the control device is arranged to remove only a proportion of build particles of a particular size from the powder material.

11 . An additive manufacturing machine according to claim 10 , wherein the proportion of build particles of a particular size removed from the powder material is variable.

12 . An additive manufacturing machine according to claim 10 , wherein the control device comprises a build particle filter for removing build particles of the particular size from the powder material and a bypass for allowing a proportion of the build particles of the particular size to bypass the build particle filter and remain in the powder material.

13 . An additive manufacturing machine according to claim 12 , wherein the control device is arranged to alter the proportion of build particles that pass through the bypass.

14 . An additive manufacturing machine according to claim 10 , wherein the particular size is particles having a size less than 10 micrometres.

15 . An additive manufacturing machine according to claim 10 , wherein the control device comprises a cyclone separator or a gas elutriation system for removing a proportion of build particles of a particular size from the powder material.

16 . An additive manufacturing machine according to claim 1 , wherein the control device comprises a delivery device for delivering particles of the material from a source and a mixer for controlling the addition of the particles from the source to the powder material.

17 . An additive manufacturing machine according to claim 12 , wherein the control device comprises a sensor for detecting a property of the powder material from which a ratio of micro or macro build particles in the powder material can be determined, the filter and/or mixer controlled in response to signals from the sensor.

18 . An additive manufacturing machine according to claim 1 , comprising a recirculation loop for recirculating powder from the build chamber to the powder dispenser.

19 . An additive manufacturing machine according to claim 18 , wherein the control device is arranged to control the particle size distribution of powder material delivered from the recirculation loop to the powder dispenser.

20 . An additive manufacturing machine according to claim 19 , wherein a sensor of the control device detects a property of the powder material in the recirculation loop and a device for altering the particle size distribution removes a proportion or adds build particles of a particular size to the powder material in the recirculating loop to alter the particle size distribution of powder material delivered from the recirculation loop to the powder dispenser.

21 . An additive manufacturing machine according to claim 1 , comprising a threshold filter for removing from the powder material particles having a size above the upper particle size limit.

22 . An additive manufacturing machine according to claim 21 , wherein the threshold filter is provided in the recirculating loop to remove particles having a size above the upper particle size limit from powder in the recirculating loop.

23 . An additive manufacturing machine according to claim 1 , wherein the control device is arranged for controlling the property of the powder during building of the object.

24 . An additive manufacturing machine according to claim 1 , wherein the control device is arranged for controlling a particle size distribution of build particles in the powder material between successive builds.

25 . An additive manufacturing machine according to claim 1 , wherein the property of the powder material is moisture content.

26 . An additive manufacturing machine according to claim 1 , wherein property of the powder material is morphology of the build particles.

27 . An additive manufacturing machine according to claim 26 , wherein the control device is arranged for controlling a distribution of different shaped build particles in the powder material.

28 . An additive manufacturing machine according to claim 1 , wherein the property of the powder material is chemical composition.

29 . A method of building an object by layerwise melting of powder material, the method comprising depositing powder material into a build chamber, spreading the deposited powder material in a layer across a build platform, selectively melting with a high energy beam powder material in each layer and controlling, during the build, a property of the powder material given by build particles in the powder material that are below an upper particle size limit specified for the build.

30 . A method according to claim 29 , wherein the property is particle-size distribution of build particles in the powder material.

31 . A method according to claim 30 , wherein controlling, during the build, a particle size distribution of build particles in the powder material comprises adding or removing particles to/from the powder material during the build.

32 . A method of building an object by layerwise melting of powder material, the method comprising depositing powder

Assignees

• Renishaw Plc

Inventors

• Mcfarland Geoffrey
• Ferrar Ben Ian

Classifications

• B29C64/393

  for controlling or regulating additive manufacturing processes · CPC title

• B22F12/90

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

• B22F12/57

  Metering means · CPC title

• B22F12/52

  Hoppers · CPC title

• B22F10/73

  of powder · CPC title