Additive manufacturing with cell processing recipes

A method of additive manufacturing includes storing a plurality of predetermined cell processing recipes, dispensing a layer of a plurality of successive layers of feed material on a platform, receiving data describing an area of the layer of the feed material to fuse, determining a combination of a plurality of non-overlapping cells that substantially cover the area, and sequentially processing the plurality of cells. Each cell processing recipe includes scan path data indicating a path for an energy beam to follow, and different cell processing recipes having different paths for the energy beam. Each cell of the plurality of cells gets an associated cell processing recipe selected from the plurality of predetermined cell processing recipes. Each cell is processed by causing an energy beam to follow the first path for the cell processing recipe associated with the cell.

TECHNICAL FIELD

This specification relates to additive manufacturing, also known as 3D printing.

BACKGROUND

Additive manufacturing (AM), also known as solid freeform fabrication or 3D printing, refers to a manufacturing process where three-dimensional objects are built up from successive dispensing of raw material (e.g., powders, liquids, suspensions, or molten solids) into two-dimensional layers. In contrast, traditional machining techniques involve subtractive processes in which objects are cut out from a stock material (e.g., a block of wood, plastic or metal).

A variety of additive processes can be used in additive manufacturing. Some methods melt or soften material to produce layers, e.g., selective laser melting (SLM) or direct metal laser sintering (DMLS), selective laser sintering (SLS), fused deposition modeling (FDM), while others cure liquid materials using different technologies, e.g., stereolithography (SLA). These processes can differ in the way layers are formed to create the finished objects and in the materials that are compatible for use in the processes.

In some forms of additive manufacturing, a powder is placed on a platform and a laser beam traces a pattern onto the powder to fuse the powder together to form a shape. Once the shape is formed, the platform is lowered and a new layer of powder is added. The process is repeated until a part is fully formed.

SUMMARY

This specification describes technologies relating to additive manufacturing.

In one aspect, an additive manufacturing apparatus includes a platform, a dispenser to deliver a plurality of successive layers of feed material on the platform, a light source to generate one or more light beams, a first galvo mirror scanner positioned to direct a first light beam onto a topmost layer of the plurality of successive layers, a second galvo mirror scanner positioned to direct a second light beam onto the topmost layer of the plurality of successive layers, and a controller configured to cause the first galvo mirror scanner to direct the first light beam to pre-heat or heat-treat an area of the topmost layer and to cause the second galvo mirror scanner to direct the second light beam to fuse the area of the topmost layer.

The controller may be configured to control the first galvo mirror scanner to direct the first light beam to both pre-heat the area before the area has been fused by the second light beam and heat-treat the area after the area has been fused. The controller may be configured to control the second galvo mirror scanner to direct the first light beam to heat-treat the area of the powder bed after the area has been fused. A plurality of heat lamps may be positioned above the powder bed. The controller may be configured to control the plurality of heat lamps to at least partially pre-heat the area of the powder bed. The controller may be configured to control the plurality of heat lamps to at least partially heat-treat the area of the powder bed after the area has been fused.

A polygon mirror scanner may be positioned to direct a third light beam onto a topmost layer of the plurality of successive layers on the platform. The controller may be configured to control the polygon laser scanner to cause the third light beam to at least partially heat-treat the area of the powder bed after the area has been fused. The controller may be configured to control the polygon laser scanner to cause the third light beam to at least partially pre-heat the area of the powder bed before the area has been fused. The light source may be a laser and the energy beam may be a laser beam. The controller may be configured to cause the first mirror galvo scanner to direct the first light beam to follow a first path on the topmost layer of feed material and to cause the second galvo mirror scanner to direct the second light beam to follow a second path on the topmost layer of feed material.

In another aspect, an additive manufacturing apparatus include a platform, a dispenser to deliver a plurality of successive layers of feed material on the platform, one or more energy sources to provide pre-heating, fusing, and heat-treating of a layer of feed material, the one or more energy sources configured to provide fusing of selectable voxels of the feed material, and a controller. The controller is configured to store a plurality of predetermined cell processing recipes, each cell processing recipe including scan path data indicating a path for an energy beam to follow to process one or more voxels of the feed material within a cell that encompasses a plurality of voxels, with different cell processing recipes having different paths for the energy beam, receive data describing an area of a layer of the feed material to fuse, determine a combination of a plurality of non-overlapping cells that substantially cover the area, each cell of the plurality of cells having an associated cell processing recipe selected from the plurality of predetermined cell processing recipes, and cause the one or more energy sources to sequentially process the plurality of cells, and for each cell causing the one or more energy sources to generate an energy beam and cause the energy beam to follow the first path for the cell processing recipe associated with the cell.

Each cell processing recipe may include first scan path data indicating a first path for an energy beam to follow within the cell to pre-heat the one or more voxels of the feed material within the cell. The controller may be configured to control a galvo mirror scanner to direct the energy beam along the first scan path. The controller may be configured to control a polygon mirror scanner to direct the energy beam along the first scan path. Each cell processing recipe may include second scan path data indicating a second path for an energy beam to follow within the cell to fuse the one or more voxels of the feed material within the cell. The controller may be configured to control a galvo mirror scanner to direct the energy beam along the second scan path.

Each cell processing recipe may include third scan path data indicating a third path for an energy beam to follow within the cell to heat-treat the one or more voxels of the feed material within the cell. The controller may be configured to control a galvo mirror scanner to direct the energy beam along the third scan path. The controller may be configured to control a polygon mirror scanner to direct the energy beam along the third scan path.

Each cell processing recipe may include first scan path data indicating a first path for an energy beam to follow within the cell to pre-heat the one or more voxels of the feed material within the cell, and second scan path data indicating a second path for an energy beam to follow within the cell to fuse the one or more voxels of the feed material within the cell, and different cell processing recipes may have at least one of different first paths or different second paths for the energy beam.

Each cell processing recipe may include second scan path data indicating a second path for an energy beam to follow within the cell to fuse the one or more voxels of the feed material within the cell, and third path data indicating a third path for an energy beam to follow within the cell to heat-treat the one or more voxels of the feed material within the cell, and different cell processing recipes may have at least one of different second paths or different third paths for the energy beam.

Particular implementations of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages. Pre-heating and post-heating can be controlled. The amount of power needed by the beam used for fusing can be reduced, and/or the beam can move more quickly across the layer and thus can increase throughput. In addition, the frequency and severity of temperature deviations away from a preferred processing temperature set point can be reduced. Reducing temperature deviations is advantageous for reducing thermal stress, improving melt pool keyhole depth and stability, and reducing microstructure variation due to thermal variation. These processing advantages directly improve part porosity, fatigue resistance, yield strength, and can simplify post processing.

DETAILED DESCRIPTION

An additive manufacturing process can involve dispensing a layer of feed material, for example, a powder, on a platen or a previously deposited layer, followed by a method to fuse portions of the layer of feed material. An energy source heats up the feed material and causes it to solidify, e.g., to cause the powder to fuse. However, precise thermal control can be needed to meet part quality and yield requirements. Overheating can result in porosity due to unstable melt pool keyhole formation and collapse during the melting process. On the other hand, if too little heat is applied or too much heat is lost then fusing can be incomplete. In addition, warping, stress-induced cracking and deformation can occur if there is a steep spatial thermal gradient over the top layer.

In an additive manufacturing process, the feed material can be heated prior to being deposited over the platen. This can reduce the amount of power needed by the scanning beam to cause a particular voxel to solidify. This permits the beam to move more quickly across the layer, and thus can increase throughput. In addition, this can reduce the size of the temperature fluctuations, and thus reduce thermal stress and improve material properties.

Pre-heating a platform that supports the powder can control the temperature profile of the top layers for short parts, but fails to alleviate and can even exasperate temperature control for tall parts. Heat conducted from the platform to the part will not reach the top layers of tall parts because the distance from the pre-heated platform to the topmost layer of feed material is too great as the build progresses. Increasing the amount of heat from the platform to try heat the top layers of tall parts causes the bottom layers to be over-heated.

However, a feed powder and the topmost melted layers can be pre-heated by a fixed or scanned light beam prior to fusing in order to reduce the thermal gradient during the manufacturing process, which can improve sintering quality and throughput. The reduced thermal gradient can at least partially reduce thermal stresses during the manufacturing process. Heat can also be applied by a scanned or fixed light beam to the fused sections after fusing (also referred to as “heat-treating” or “post-heating”) in order to control the rate of cool-down and thereby reduce residual stresses and further improve sintering quality, e.g., by reducing the likelihood of warping and cracking of the part. The heat can also be used to compensate for thermal non-uniformity due to radiative, convective, and conductive losses.

This disclosure describes a method and apparatus for additive manufacturing. The apparatus can include an optical engine with at least one galvo mirror scanner and an array of heat lamps. An optical assembly that includes such an optical engine is capable of directing one or more light beams to pre-heat, fuse, and/or heat-treat a feed material during the manufacturing process.

Particular implementations involve different energy point sources such as filaments or diodes and optical elements such as reflectors or lenses for directing and shaping the radiation-based heating profile on the platform. IR lamp arrays can simultaneous apply patterned or uniform radiation from one or more IR lamp filaments to the platform. Reflecting and focusing elements influence the heating profile on a platform under an IR lamp array. An IR lamp array can apply heat for a duration from seconds to hours and is scalable beyond one meter square platforms.

In some cases, it is necessary to heat a small region within the heat affected zone of an individual IR lamp, e.g., when building parts or portions of larger parts that are smaller than the typical spot size of an IR lamp. Polygon heating can be more effective than IR lamps because the diode spot incident on the feed material is substantially less diffuse and more focused at the millimeter scale or smaller. Galvo heating can be similar to polygon heating for facilitating higher watt density and smaller spot size than IR lamps. Furthermore, galvo heating has an added advantage of enabling heating of fine and complex patterns. For example, galvo heating is suitable for heating regions that will correspond to thin walls found in heat exchangers. The advantage of polygon heating over galvo heating is higher laser utilization due to reduced time turning off the point source while orienting steering mirrors. Thus, polygon heating is more effective at heating regular polygon shaped patterns. Polygon shaped patterns can be used to fill the hatch area of the part.

An example implementation of the subject matter IR lamp heating to elevate and maintain the part at elevated temperature to reduce residual stress, polygon heating concurrent with laser melting to maintain portions of the hatch region of the topmost layer at an elevated temperature to control the cooling local rate, and galvo heating concurrent with laser melting to maintain contours and thin wall sections at elevated temperature to control the local cooling rate. It is noteworthy that the example implementation addresses temperature control on the topmost layer and as the part becomes taller. The present techniques are compatible with conventional build plate heaters that direct heat from the bottom.

FIG. 1shows an example additive manufacturing system100. The additive manufacturing system100includes a build platform116to hold the object being fabricated, a feed material delivery system107to deliver successive layers104of feed material105over the platform116, and an optical assembly111to generate multiple light beams that will be used for fusing, pre-heating and/or heat-treatment of each layer of feed material.

In some implementations, such as the implementation illustrated inFIG. 1, the feed material delivery system107can include a flat blade or paddle107ato push a feed material105from a feed material reservoir108across the build platform116. In such an implementation, the feed material reservoir108can also include a feed platform118positioned adjacent the build platform116. The feed platform118can be elevated to raise some feed material above the level of the build platform116, and the blade or paddle107acan push the feed material105from the feed platform118onto the build platform116.

Alternatively or in addition, the feed material delivery system107can include a dispenser that is suspended above the platform116and that has a plurality of apertures or nozzles through which the powder is metered and flows. For example, the powder could be throttled or otherwise metered through an element restrictive to flow under gravity, or be ejected, e.g., by piezoelectric actuator. Control of dispensing of individual apertures or nozzles could be provided by pneumatic valves, microelectromechanical systems (MEMS) valves, solenoid valves, and/or magnetic valves. Other systems that can be used to dispense powder include a roller having apertures, and an augur inside a tube having a plurality of apertures.

Optionally, the system100can include a compaction and/or levelling mechanism to compact and/or smooth the layer of feed materials deposited over the build platform116. For example, the system can include a roller or blade that is movable parallel to the surface of the platform116by a drive system, e.g., a linear actuator.

The feed material105can include metallic particles. Examples of metallic particles include metals, alloys and intermetallic alloys. Examples of materials for the metallic particles include aluminum, titanium, stainless steel, nickel, cobalt, chromium, vanadium, and various alloys or intermetallic alloys of these metals.

The feed material105can include ceramic particles. Examples of ceramic materials include metal oxide, such as ceria, alumina, silica, aluminum nitride, silicon nitride, silicon carbide, or a combination of these materials, such as an aluminum alloy powder.

The feed material can be dry powders or powders in liquid suspension, or a slurry suspension of a material. For example, for a dispenser that uses a piezoelectric printhead, the feed material would typically be particles in a liquid suspension. For example, a dispenser could deliver the powder in a carrier fluid, e.g. a high vapor pressure carrier, e.g., Isopropyl Alcohol (IPA), ethanol, or N-Methyl-2-pyrrolidone (NMP), to form the layers of powder material. The carrier fluid can evaporate prior to the sintering step for the layer. Alternatively, a dry dispensing mechanism, e.g., an array of nozzles assisted by ultrasonic agitation and pressurized inert gas, can be employed to dispense the first particles.

The additive manufacturing system100includes a controller119that can store digital data representing a pre-defined pattern that can form the object106. The controller119controls the optical assembly111to generate multiple light beams that will be used for fusing, pre-heating and/or heat-treatment of the layer of feed material.

The optical assembly111can include an array of heat lamps120that can include one or more heat lamps120a. Each heat lamp120ais capable of generating a light beam121to impinge the outer most layer104aof the feed material105. Each light beam can provide heat to the feed material105on a specified section of the platform116. The heat can be used to at least partially pre-heat or heat treat a portion of the feed material105.

The optical assembly111includes a light source101to generate a light beam102to impinge the outermost layer104aof the feed material105. The light beam102selectively delivers sufficient heat to fuse the feed material105according to the pre-defined pattern stored in the controller119. Fusing in the context of this specification can include melting and solidification, or sintering while still in solid form, or other processes of fusing a powder. While the illustrated implementation utilizes a single light source emitting a single light beam, multiple light sources can be used to generate multiple light beams. Examples of such implementations are given in greater detail later within this disclosure.

In general, the light beam102generated by the light source101has a spot size corresponding to (or is controllable to selectively fuse) an individual voxel of feed material. In contrast, the light beam121generated by each lamp120ahas a larger spot on the feed material than the light beam102. The light beam121can span multiple voxels, e.g., at least a 5×5 voxel area.

The light beam102is caused by an optical engine103to scan at least along a first axis (also referred to as a Y-axis). The optical engine103is controlled by the controller119and is described in greater detail later within this disclosure.

The Y-axis can be parallel to the direction of motion of the dispenser107(e.g., from left to right inFIG. 1), e.g., the blade or nozzles, across the platform. Alternatively, the Y-axis can be perpendicular to the direction of motion of the dispenser107.

Movement of the light beam102along the X-axis can be facilitated by motion of the platform116, motion of a support holding the optical engine103, by tilting a portion of the optical engine103about the Y-axis, by using dual-axis galvo mirror, or by placing a separate galvo mirror scanner positioned before or after the optical engine103and within the path of the light beam101to deflect the light beam101along the X-axis.

Where the light source101generates multiple light beam, different light beams can use different mechanisms to provide movement along the X-axis. For example, the galvo mirror scanner202can have a second galvo mirror scanner202b. In some implementations, motion of the different light beams along the X-axis can be independently controlled. In some implementations, e.g., where the scanners are attached to the same support that is laterally movable, the light beams have a fixed relative position relative to the support along the X-axis.

Movement of the light beam(s)121along the X-axis can be facilitated by motion of the platform116, or motion of a support holding the lamp array120. In some implementations, the lamp array120is fixed to the same movable support as the optical engine103; in this case a single actuator can be used to move both synchronously along the X-axis. In some implementations, the lamp array120and the optical engine103have separate supports and are independently movable.

FIGS. 2A-2Cshow top, front, and side views, respectively, of an example optical engine103. The optical engine103can include a mirror scanner202a, such as a galvo mirror scanner. The galvo mirror scanner202athat includes a movable mirror204and focusing lenses206. The galvo mirror scanner202acan direct a light beam, such as light beam102, to impinge a layer of the feed material105on the platform116. The focusing lenses206focus the light beam102in order to provide a desired spot size at the outermost layer104aof the feed material. The galvo mirror scanner202can be used for pre-heating the feed powder105, fusing the feed powder105, or heat-treating the feed powder105after it is fused, or any combination. Heat-treating in the context of this disclosure includes controlling a rate of cooling of the feed material after it has been fused.

The optical engine103can also include a second mirror scanner202b, such as a second galvo mirror scanner202b. The second galvo mirror scanner202bcan direct a second light beam to impinge a layer of the feed material105on the platform116. In construction, the second galvo mirror scanner202bcan otherwise be similar to the galvo mirror scanner202a. The second mirror scanner202bcan be used for pre-heating the feed powder105, fusing the feed powder105, or heat-treating the feed powder105after it is fused, or any combination. Heat-treating in the context of this disclosure includes controlling a rate of cooling of the feed material after it has been fused.

Alternatively, referring toFIG. 2D, a rotating polygonal mirror scanner202ccan be used for either or both mirror scanners202aand202b. The rotating polygonal mirror scanner202cthat includes a rotatable polygon204cwith mirrored sides and focusing lenses206. As the polygon rotates, the light beam102is swept across the layer of feed material.

In some implementation, the first mirror scanner202a, e.g., a galvo mirror scanner, is used for pre-heating the feed powder105, and the second mirror scanner202b, e.g., a galvo mirror scanner, is used for fusing the feed material105. In some implementation, the first mirror scanner202a, e.g., a galvo mirror scanner, is used for fusing the feed material105, and the second mirror scanner202b, e.g., a galvo mirror scanner, is used for heat-treating the fused feed material105. In some implementation, the first mirror scanner202a, e.g., a galvo mirror scanner, is used for both pre-heating and heat-treating the feed powder105, and the second mirror scanner202b, e.g., a galvo mirror scanner, is used for fusing the feed material105.

For each light beam, as the light beam sweeps along a path on the layer, the light beam can be modulated, e.g., by causing the respective light source to turn the light beam on and off, in order to deliver energy to selected regions of the layers of feed material110. A set of example scan regions is shown inFIGS. 3A-3D.

InFIG. 3A, a first light path can be traced with a galvo mirror scanner, such as the second galvo mirror scanner202b. The light beam following this path can raise the temperature of a feed material above a fusion temperature. This technique can be used to fuse the contour of the object being fabricated; the interior of the object can be fused separately.

The controller119can store a multiple predetermined cell processing recipes. A cell is an area of the feed material that encompasses multiple voxels. Each cell processing recipe includes scan path data indicating a path for an energy beam to follow to process one or more voxels of the feed material within a cell. Different cell processing recipes having different paths for the energy beam.

The controller is configured to receive data, e.g., in a computer readable format, describing an area of a layer of the feed material to fuse in order to form the object. For example, the contour of the area to fuse can be the initial outline traced by the galvo mirror scanner inFIG. 3A.

The controller is also configured to determine a combination of a plurality of non-overlapping cells that substantially cover the area. Each cell has an associated cell processing recipe. i.e., one of the stored plurality of predetermined cell processing recipes. In effect, the controller breaks the area to be fused into individual cells, each having an associated cell processing recipe. An example polygon cell304(in this case a trapezoid) is illustrated inFIGS. 3B-3D.

The controller119is also capable of causing one or more energy sources to sequentially process the plurality of cells. For each cell, the controller119can cause the light source101to generate the light beam102and cause the mirror scanner to direct the light beam to follow the path identified by the cell processing recipe associated with the cell.

Each cell processing recipe can include first scan path data that indicates a first path306afor the light beam to follow within the cell to pre-heat the one or more voxels of the feed material within the cell. For example, the controller119can control a galvo mirror scanner, such as the galvo mirror scanner202a, to direct the light beam along the first scan path306a. In some implementations, a polygon mirror scanner can be used in the place of or in addition to the galvo mirror scanner. In this case, the path will be a set of parallel lines.

Each cell processing recipe can also include a second scan path data indicating a second path306bfor a light beam to follow within the cell to fuse the one or more voxels of the feed material within the cell. For example, the controller119can control a galvo mirror scanner, such as the galvo mirror scanner202b, to direct the energy beam along the second scan path306b. The second path306bneed not be the same as the first path306a. In some implementations, a polygon mirror scanner can be used in the place of or in addition to the galvo mirror scanner. In this case, the path will be a set of parallel lines.

Each cell processing recipe can also include a third scan path data indicating a third path306cfor an energy beam to follow within the cell to heat-treat the one or more voxels of the feed material within the cell. For example, the controller119can control a galvo mirror scanner, such as the galvo mirror scanner202b, to direct the energy beam along the third scan path306c. In some implementations, a polygon mirror scanner can be used in the place of or in addition to the galvo mirror scanner. The third path306cneed not be the same as the first path306aor the second path306b.

In all of the examples previously described, different cell processing recipes can have at least one of different first paths306aor different second paths306bfor the energy beam. Similarly, all of the examples previously described can include different cell processing recipes that have at least one of different second paths306bor different third paths306cfor the energy beam. That is, a scan pattern of the first path306acan be different from a scan pattern of the second path306b, and a scan patter of the second path306bcan be different than a scan pattern for the third path306c.

FIG. 4Ashows an example of a light source101configuration that can be implemented with aspects of this disclosure. In the illustrated implementation, the light source101emits a first light beam302towards a beam splitter304. The beam splitter304can split the first light beam302emitted from the light source101into a second light beam302a, a third light beam302b, and a fourth light beam302c. The second light beam302ais directed towards the first galvo mirror scanner202a, the third light beam302bis directed towards the second galvo mirror scanner202b, and the fourth light beam302cis directed towards a third galvo mirror scanner202c. While the illustrated implementation shows the beam splitter304directing a light beam to three different optical components, the beam splitter304can be configured to direct any number of light beams. For example, if the optical engine103included only the first galvo mirror scanner202aand the second galvo mirror scanner202b, then the beam splitter304may only produce the second light beam302aand the third light beam302b. In some implementations, power density of the first light beam302can be modulated by the light source101. In some implementations, the beam splitter can include a power density modulation mechanism for one or more of the light beams. In some implementations, one or more separate, stand-alone power density modulation mechanisms can be used.

FIG. 4Bshows an example optical engine that configuration that can be implemented with aspects of this disclosure. The illustrated implementation includes a first light source304a, a second light source304b, and a third light source304c. The first light source304aemits the first light beam302atowards the first galvo mirror scanner202a. The second light source304bemits the second light beam302btowards the second galvo mirror scanner202b. The third light source304cemits the third light beam302ctowards the third galvo mirror scanner202c.

While the illustrated implementation shows three separate light sources directing a light beam to three different optical components, any number of light sources can be used. For example, if the optical engine103included only the first galvo mirror scanner202aand the second galvo mirror scanner202b, then the first light source304aand the second light source may be the only included light sources. Each of the light sources can individually modulate the power density of the light beams. In some implementations, one or more separate, stand-alone power density modulation mechanisms can be used.

While the beam splitter304and the use of multiple light sources304a,304b, and304chave been described in separate implementations, the two concepts can be used in combination. For example, a first light beam can be emitted from a first light source towards a beam splitter. The beam splitter can split the first light beam into a second and third light beam. The second light beam can be directed to the first galvo mirror scanner202awhile the third light beam can be directed towards the second galvo mirror scanner202b. A second light source can emit a fourth light beam towards the third galvo mirror scanner202c.

In some aspects of operation, the controller119can cause the light source101and galvo mirror scanner202to apply a light beam to at least a portion of the region of the layer of feed material105as shown inFIG. 5. In such an implementation, a heat lamp120can also emit a wide energy beam502to at least a portion of the region of the layer of feed material105.

In some aspects of operation, the controller119is configured to control the first galvo mirror scanner202ato both pre-heat an area of the feed material105before the area has been fused by the second galvo mirror scanner202band heat-treat the area after the area has been fused by the second galvo mirror scanner202b. The controller119can control the second galvo mirror scanner202bto direct a light beam to heat-treat the area of the feed powder105after the area has been fused by the second galvo mirror scanner202b.

In some aspects of operation, the controller can control the plurality of heat lamps120to at least partially pre-heat the area of the feed powder105. The controller can also control the plurality of heat lamps to at least partially heat-treat the area of the feed powder105after the area has been fused.

In some implementations, a polygon mirror scanner can be positioned to direct a third light beam onto a topmost layer of the feed powder105. In such an implementation the controller can control the polygon mirror scanner to direct a light beam at least partially heat-treat the area of the feed powder105after the area has been fused by the second galvo mirror scanner202b. The controller can also control the polygon mirror scanner to at least partially pre-heat the area of feed powder105before the area has been fused by the light beam from the galvo mirror scanner202b.

In some implementations, the additive manufacturing system100includes another heat source, e.g., one or more IR lamps arranged to direct heat onto the uppermost layer of the feed material. After pre-heating the first area of the layer of the feed material using the other heat source, a second area of the layer of the feed material can be pre-heated with the polygon mirror scanner, such as the polygon mirror scanner208a, reflecting the first light beam onto the second area of the layer of the feed material. The second area can be different from the first area of the layer of the feed material. After fusing the first area of the layer of the feed material, the second area of the layer of the feed material can be fused with a galvo mirror scanner, such as the galvo mirror scanner202, reflecting the second light beam onto the second area of the layer of the feed material after the first area has been pre-heated. The second area can be different from the first area of the layer of the feed material.

Controllers and computing devices can implement these operations and other processes and operations described herein. As described above, the controller119can include one or more processing devices connected to the various components of the system100. The controller119can coordinate the operation and cause the apparatus100to carry out the various functional operations or sequence of steps described above.

The controller119and other computing devices part of systems described herein can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware. For example, the controller can include a processor to execute a computer program as stored in a computer program product, e.g., in a non-transitory machine readable storage medium. Such a computer program (also known as a program, software, software application, or code) can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.

The controller119and other computing devices part of systems described can include non-transitory computer readable medium to store a data object, e.g., a computer aided design (CAD)-compatible file that identifies the pattern in which the feed material should be deposited for each layer. For example, the data object could be a STL-formatted file, a 3D Manufacturing Format (3MF) file, or an Additive Manufacturing File Format (AMF) file. For example, the controller could receive the data object from a remote computer. A processor in the controller119, e.g., as controlled by firmware or software, can interpret the data object received from the computer to generate the set of signals necessary to control the components of the system100to fuse the specified pattern for each layer.

The processing conditions for additive manufacturing of metals and ceramics are significantly different than those for plastics. For example, in general, metals and ceramics require significantly higher processing temperatures. Thus 3D printing techniques for plastic may not be applicable to metal or ceramic processing and equipment may not be equivalent. However, some techniques described here could be applicable to polymer powders, e.g. nylon, ABS, polyetheretherketone (PEEK), polyetherketoneketone (PEKK) and polystyrene.

Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims.Optionally, some parts of the additive manufacturing system100, e.g., the build platform116and feed material delivery system107, can be enclosed by a housing. The housing can, for example, allow a vacuum environment to be maintained in a chamber inside the housing, e.g., pressures at about 1 Torr or below. Alternatively, the interior of the chamber can be a substantially pure gas, e.g., a gas that has been filtered to remove moisture, oxygen, and/or particulates, or the chamber can be vented to atmosphere. Pure gas can constitute inert gases such as argon, nitrogen, xenon, and mixed inert gases.The techniques can be used for hybrid additive manufacturing wherein material is locally fused to a base part or added to repair or rework damaged parts.

In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results.