Additive manufacturing chamber with reduced load

A disclosed additive manufacturing machine includes a fixed platform defining a work surface for supporting fabrication of a part and a housing defining a chamber over the work surface. A material applicator is supported on the housing for depositing material onto the work surface. An energy directing device is also supported on the housing and directs energy within the chamber to form a part. The housing is movable relative to the work surface therefore moves the energy producing device relative to the work surface to maintain a distance between the energy directing device and a surface of the part during fabrication.

BACKGROUND

This disclosure generally relates to an additive manufacturing machine and process. More particularly, this disclosure relates to a configuration compensating for increased size and weight of larger parts generated in an additive manufacturing process.

Typical manufacturing methods include various methods of removing material from a starting blank of material to form a desired completed part shape. Such methods utilize cutting tools to remove material to form holes, surfaces, overall shapes and more by subtracting material from the starting material. Such subtractive manufacturing methods impart physical limits on the final shape of a completed part. Additive manufacturing methods form desired part shapes by adding one layer at a time and therefore provide for the formation of part shapes and geometries that would not be feasible in part constructed utilizing traditional subtractive manufacturing methods.

Additive manufacturing utilizes an energy source such as a laser beam to melt layers of powdered metal to form the desired part configuration layer upon layer. The laser forms a melt pool in the powdered metal that solidifies. The works surface and part are then moved downward and another layer of powdered material is then spread over the formerly solidified part and melted to the previous layer to build a desired part geometry layer upon layer. Powdered material that is applied but not melted to become a portion of the part accumulates around and within the part. For smaller parts the excess powdered material is not significant. However, as capabilities improve and larger parts are fabricated, the excess powdered metal becomes a significant consideration in both part fabrication capabilities and economic feasibility.

SUMMARY

An additive manufacturing process according to an exemplary embodiment of this disclosure includes defining a fixed work surface and housing at least partially surrounding the fixed work surface, depositing material within the housing, directing energy on portions of the deposited material according to a defined part geometry, and moving the housing vertically relative to the fixed work surface by a single powder layer thickness to maintain a vertical spacing between the housing and the part during fabrication.

In a further embodiment of the foregoing additive manufacturing process, includes retaining deposited material on the work surface about a periphery of the part during fabrication.

In a further embodiment of any of the foregoing additive manufacturing processes, includes the energy producing device supported by the housing moving relative to the work surface.

In a further embodiment of any of the foregoing additive manufacturing processes, includes supporting a material depositing device on the housing and moving the material depositing device with the housing.

In a further embodiment of any of the foregoing additive manufacturing processes, includes moving the housing with at least one actuator attached to a platform and fixed relative to the work surface.

In a further embodiment of any of the foregoing additive manufacturing processes, includes moving the housing incrementally a distance substantially equal to a thickness of at least one layer of deposited material.

In a further embodiment of any of the foregoing additive manufacturing processes, includes moving the housing a distance determined to maintain a desired focal length between the energy directing device and a surface of the part during fabrication.

An additive manufacturing machine according to an exemplary embodiment of this disclosure includes a fixed platform defining a work surface for supporting fabrication of a desired part geometry, a housing defining a chamber at least partially defined by the work surface; a material applicator supported on the housing for depositing material onto the work surface, and an energy directing device supported on the housing and directing energy within the chamber according to a desired part geometry. The housing is movable relative to the work surface to maintain a distance between the energy directing device and a surface of the part during fabrication.

In a further embodiment of the foregoing additive manufacturing machine, includes an actuator for moving the housing relative to the work surface.

In a further embodiment of any of the foregoing additive manufacturing machines, includes a controller governing movement of the housing relative to the work surface.

In a further embodiment of any of the foregoing additive manufacturing machines, the controller maintains the distance between the energy producing device and a surface of the part by moving the housing relative to the work surface a distance corresponding with a thickness of a layer of deposited material.

In a further embodiment of any of the foregoing additive manufacturing machines, material deposited on the work surface is maintained about the part during fabrication.

In a further embodiment of any of the foregoing additive manufacturing machines, the housing includes walls supporting a top and the energy directing device is supported on the top.

In a further embodiment of any of the foregoing additive manufacturing machines, the material applicator is mounted to at least one of the walls.

In a further embodiment of any of the foregoing additive manufacturing machines, the material applicator is movable across the work surface for depositing material.

DETAILED DESCRIPTION

Referring toFIG. 1, an additive manufacturing machine10includes a housing25that defines a chamber28and an energy transmitting device20for directing an energy beam22on or above a work surface12on which a part30is fabricated. In this example, the energy transmitting device20emits a laser beam22for melting material26deposited by a material applicator24. The example material26is a metal powder that is applied in a layer over the work surface12and subsequently melted according to a specific, desired part configuration by the beam22.

In this example, the beam22comprises a laser beam emitted by the energy transmitting device20. However, other energy transmitting devices may be utilized to melt material in the desired configuration of the part30. The beam22directs energy onto the metal powder26laid on the work surface12to melt subsequent layers to form the desired configuration30.

The additive manufacturing process utilizes layers of material26applied upon the work surface12along with the beam22to melt subsequent layers, thereby forming the desired part configuration. A controller36governs operation of the energy transmitting device20along with the material applicator24. The controller36guides the beam22to form the desired part configuration by focusing energy from the beam22on the layer of powdered material26over the part30to melt portions of the powdered metal material according to predefined part geometry. Subsequent cooling of the melted material solidifies the melted portions of the material26to the part30to grow the part from the surface12upward until complete.

Initially the material applicator24sweeps across the work surface12to disperse a layer of material26over the entire work surface12. As appreciated, the portions of material26that are not part of the part geometry30are not melted but remain on the surface12. With increasing size and capability, the amount of material that remains within the chamber28and not part of the fabricated part30can become significant.

In this example, the work surface12is part of a platform14mounted to a rigid base16. The platform14and the base16are fixed. The housing25includes walls18that are engaged to actuators32. The walls18and housing25are movable upward relative to the fixed base14. Accordingly, the walls18and platform14define a chamber that is not of a fixed size but instead varies during part fabrication. The shape and number of walls18may vary as appropriate to the configuration of part30.

FIG. 1illustrates an initial position where the housing25disposes the energy source20at a height48above the work surface12. The example part30includes a configuration that when completed is taller than the space provided within the chamber28at the initial position shown inFIG. 1.

In the initial process, the material applicator24sweeps across the work surface12and lays down a layer of material26. The energy transmitting device20sweeps the laser beam22to melt material26according to the desired geometry of the part30. Once the initial layer of the part30has been formed, the walls18are moved upwardly away from the work surface12by the actuators32as is dictated by the controller36. The amount of movement relative to the number of sweeps of the applicator24is minimal as each layer represents a very small thickness of material that is applied over the part30. Accordingly, the walls18are moved incrementally upward away from the work surface12to provide a controlled layering of powdered material26above part30.

Referring toFIG. 2, the example additive manufacturing machine10shown in an intermediate position where the walls18had been moved upwardly34such that the height48has increased. Moreover, the amount of material26that is contained within the chamber28has increased. As the material applicator24sweeps across the work surface12, material is distributed over the working surface12and the part30. The energy producing device20melts material according to the proximate geometry of the part30. The remaining excess powder simply remains on the work surface12and accumulates around the part.

The platform14is supported on a rigid base16and therefore does not move and maintains a desired position. The laser beam20is moved upwardly with the walls18and housing25and therefore also maintains a desired distance from the surface of the part30. Movement of the walls18are governed by the controller36such that the layer of powdered material26deposited upon part30and over working surface16is controlled to the desired thickness. Beam22is swept across the part30to provide the required melting and solidification of powdered material26.

As the part30grows in height, the walls18and housing25is moved upwardly such that the height within the chamber28grows in concert with the height of the part30. Accordingly, layer of powdered material26deposited upon part30and over working surface12is controlled to the desired thickness. The beam22can remain focused on the powdered material26above the upper surface of the part30during manufacture of the part without moving the platform14or the base16.

Referring toFIG. 3, the additive manufacturing machine10is shown in a position where the part30is substantially in completed form. In this position, the housing25are extended such that the part30has grown within the chamber28. Moreover, the amount of material26surrounding the part30has increased such that the weight supported by the base14is substantial. However, because the platform14and base16are rigidly fixed, the weight of the material26does not substantially affect the fabrication process of the part30or the load on actuators32. As appreciated, movement of the walls18and housing25relative to the part30maintains the desired powdered material26layer thickness upon the part30. The mass of non-melted material26surrounding the part30does not affect nor does it cause movement or other disruptions of the process.

In operation, the example additive manufacturing machine10provides for the fabrication of a desired part beginning with an application of a layer of material26to the work surface12. After each application of material26to the work surface12, the energy beam22melts material to add an additional layer of to form the part30.

After each layer the housing18will be incremented upward a distance determined to comply with the addition of a subsequent layer of material to the part30. After application of each layer of material to the part30, the unused material26surrounding the part30is simply maintained within the chamber28. The walls18are incremented upward to increase the height48within the chamber28to both maintain the desired height relationship between the top of the walls18and the applicator24to the top of the part30while also compensating and providing additional space for the part30if required.

Accordingly, the example manufacturing machine10and process provides for the fabrication of larger parts within increased mass of both the part and excess material surrounding the part without the additional cost, expense, and control required to handle the increased weight and mass.