Patent Description:
Additive manufacturing processes and techniques enable fabrication of components having geometries that are difficult or otherwise impossible to make using other fabrication techniques. For example, components in gas turbine engines may include complex arrays of internal channels for conveying coolants or lubricants that are difficult or impossible to fabricate using more conventional fabrication techniques, such as casting or molding techniques. Additive manufacturing techniques and related advances facilitate formation of such channels having complex geometries or high-aspect ratios (e.g., channels where the ratio of channel length to a characteristic cross sectional dimension is large). However, because of limitations inherent in the additive manufacturing process, and even in other fabrication processes, various internal surfaces of these channels may exhibit distortions or surface roughness following fabrication. For example, down-facing surfaces of circular or similarly shaped channels may include undesirable distortions or surface roughness resulting from material property variations in the vicinity of the weld pool that occur while generating the overhanging surface (i.e., the down-facing surface) of the channel. Left unimproved, these regions of undesirable distortion or surface roughness have the potential to interfere with fluid flow through the channels of the component when used in operation.

<CIT> discloses a cutting system according to the preamble of claim <NUM> and describes a remote controlled actuator, which includes a spindle for holding a tool, a spindle guide section of an elongated configuration, a distal end member rotatably supporting the spindle, and a drive unit housing connected to a base end of the spindle guide section. The distal end member is fitted to the spindle guide section for alteration in attitude. The spindle guide section includes an outer shell pipe, a rotary shaft, and guide pipe.

The invention provides a cutting system for removing an excess material along a length of a channel constructed using an additive manufacturing process as claimed in claim <NUM>.

In various embodiments, a fulcrum is disposed upstream of the cutter head. In various embodiments, the fulcrum is configured to rotate with the drive cable.

In various embodiments, a directional cable is configured to direct the cutter head through the channel. In various embodiments, the directional cable is connected to the cutter base. In various embodiments, the directional cable is connected to a cutter pedestal. In various embodiments, the cutter base is configured to rotate relative to the cutter pedestal and the cutter pedestal is configured to remain stationary with respect to the drive cable.

While the drawings illustrate various embodiments described herein, the drawings do not limit the scope of the claims.

While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that changes may be made without departing from the scope of the claims.

Referring now to the drawings, <FIG> schematically illustrates a gas turbine engine <NUM>. The fan section <NUM> drives air along a bypass flow path B in a bypass duct defined within a nacelle <NUM>, while the compressor section <NUM> drives air along a core or primary flow path C for compression and communication into the combustor section <NUM> and then expansion through the turbine section <NUM>. Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, the concepts described herein are not limited to use with two-spool turbofans as the teachings may be applied to other types of turbine engines.

The gas turbine engine <NUM> generally includes a low speed spool <NUM> and a high speed spool <NUM> mounted for rotation about an engine central longitudinal axis A (with the arrow pointing in the aft direction) relative to an engine static structure <NUM> via several bearing systems <NUM>. Various bearing systems at various locations may alternatively or additionally be provided and the location of the several bearing systems <NUM> may be varied as appropriate to the application. The inner shaft <NUM> is connected to the fan <NUM> through a speed change mechanism, which in this gas turbine engine <NUM> is illustrated as a fan drive gear system <NUM> configured to drive the fan <NUM> at a lower speed than the low speed spool <NUM>. The high speed spool <NUM> includes an outer shaft <NUM> that interconnects a high pressure compressor <NUM> and a high pressure turbine <NUM>. A combustor <NUM> is arranged in the gas turbine engine <NUM> between the high pressure compressor <NUM> and the high pressure turbine <NUM>. A mid-turbine frame <NUM> of the engine static structure <NUM> is arranged generally between the high pressure turbine <NUM> and the low pressure turbine <NUM> and may include airfoils <NUM> in the core flow path C for guiding the flow into the low pressure turbine <NUM>. The mid-turbine frame <NUM> further supports the several bearing systems <NUM> in the turbine section <NUM>. The inner shaft <NUM> and the outer shaft <NUM> are concentric and rotate via the several bearing systems <NUM> about the engine central longitudinal axis A, which is collinear with longitudinal axes of the inner shaft <NUM> and the outer shaft <NUM>.

The air in the core flow path C is compressed by the low pressure compressor <NUM> and then the high pressure compressor <NUM>, mixed and burned with fuel in the combustor <NUM>, and then expanded over the high pressure turbine <NUM> and the low pressure turbine <NUM>. The low pressure turbine <NUM> and the high pressure turbine <NUM> rotationally drive the respective low speed spool <NUM> and the high speed spool <NUM> in response to the expansion. It will be appreciated that each of the positions of the fan section <NUM>, the compressor section <NUM>, the combustor section <NUM>, the turbine section <NUM>, and the fan drive gear system <NUM> may be varied. For example, the fan drive gear system <NUM> may be located aft of the combustor section <NUM> or even aft of the turbine section <NUM>, and the fan section <NUM> may be positioned forward or aft of the location of the fan drive gear system <NUM>.

Various components of the gas turbine engine <NUM> include conduits, channels or passageways extending through the component or a portion thereof. For example, components in the gas turbine engine <NUM> may include internal channels for conveying a coolant. Such components include, for example, the blades and the stators that comprise the compressor and turbine sections described above. Such components may also comprise internal channels for conveying bleed air from the compressor to other areas of the gas turbine engine <NUM> benefitting from a source of high-pressure cooling fluid. Other components comprising conduits, channels or passageways include the lubrication system, where lubricants are delivered from a pump to bearings and the like. Many of these various components are constructed using additive manufacturing techniques and include conduits, channels or passageways having curved or straight portions or combinations thereof with an internal surface having undesirable roughness or distortion, particularly along a length of a down-facing surface, following the additive manufacturing process.

Referring now to <FIG>, a component <NUM>, fabricated through additive manufacture, is illustrated. The component <NUM> includes a channel <NUM> (e.g., an internal channel, conduit or passageway) extending from a first end <NUM> to a second end <NUM>. The channel <NUM> is defined by an inner surface <NUM> that, in various embodiments, is generally circular in cross section from the first end <NUM> to the second end <NUM>. As illustrated, the inner surface <NUM> of the channel <NUM> may be characterized by an undesirable degree of surface roughness along a down-facing surface <NUM> and an acceptable degree of surface roughness along an up-facing surface <NUM> following initial fabrication through additive manufacture. To be clear, a down-facing surface refers to a surface of overhang fabricated during the additive manufacturing process, while an up-facing surface refers to a surface of little to no overhang fabricated during the additive manufacturing process. Thus, while a down-facing surface may, in fact, face down - e.g., toward a floor or a base of an additive manufacturing machine - during the additive manufacturing process, the same is not necessarily the case during a post-processing operation where the part may be rotated in an arbitrary direction prior to post-processing or cutting or smoothing as described in detail below.

In various embodiments, the channel <NUM> is curved at one or more portions along a length defined by an arc-length distance from the first end <NUM> to the second end <NUM>. As illustrated, for example, the channel <NUM>, in various embodiments, includes a first curved portion <NUM> downstream (or upstream) of the first end <NUM>, followed by a substantially straight portion <NUM>, and then followed by a second curved portion <NUM> upstream (or downstream) of the second end <NUM>. In various embodiments, the first curved portion <NUM> may be characterized such that a line of sight does not exist between the location of the channel <NUM> where the first curved portion <NUM> commences and the location of the channel <NUM> where the first curved portion <NUM> terminates or where the substantially straight portion <NUM> commences. A similar characterization applies to the second curved portion <NUM> or any additional curved portions that may be present in a passageway. The disclosure that follows provides, among other things, apparatus and methods to reduce the surface roughness of the channel <NUM> within the component <NUM>, or other components having a various numbers of curved or straight passageways. More particularly, the disclosure provides apparatus and methods useful in smoothing distortions or surface roughness along the down-facing surface <NUM> of the channel <NUM> using the up-facing surface <NUM> as a support surface or guide. While the disclosure contemplates smoothing distortions as described above, it is noted that the apparatus and methods described herein may, in various embodiments, be used as a precursor step to subsequent finishing steps that are not typically focused on preferential removal of material from relatively rough, down-facing surfaces. Accordingly, in various embodiments, such a precursor step may be necessary or prove beneficial to the application of subsequent finishing steps where a final channel geometry (including surface smoothness) is achieved with as little subsequent finishing as possible. Further, because subsequent finishing steps typically do not remove material preferentially, there exist certain geometries that require or at least greatly benefit from application of the apparatus and methods described herein as a precursor step to subsequent finishing steps.

Referring now to <FIG>, various portions of the down-facing surface <NUM> and the up-facing surface <NUM> depicted in <FIG> are illustrated schematically in cross section. For example, referring to <FIG>, a cross section of the channel <NUM>, including the down-facing surface <NUM> and the up-facing surface <NUM>, is shown proximate the second end <NUM>. As illustrated, the down-facing surface <NUM> includes a tear drop surface <NUM> introduced through the additive manufacturing process. The tear drop surface <NUM> provides less overhang (or less unsupported downward facing surface) during the additive manufacturing process, so is less prone to developing undesirable surface roughness or is less likely to result in a failed process due to poor melting or improper function of a powder spreading mechanism. Nevertheless, in order to develop a circular cross sectional shape <NUM> intended for the channel <NUM> in finished form, an excess material <NUM> (or a region of excess material) between the tear drop surface <NUM> and the circular cross sectional shape <NUM> desired in the final component must be removed. Similarly, referring to <FIG>, a cross section of the channel <NUM>, including the down-facing surface <NUM> and the up-facing surface <NUM>, is shown proximate the substantially straight portion <NUM>. As illustrated, the down-facing surface <NUM> includes a rough surface <NUM> introduced through the additive manufacturing process at an overhanging section of the circular cross sectional shape <NUM> intended for the channel <NUM> in finished form. While the rough surface <NUM> more closely approximates the circular cross sectional shape <NUM> than does the tear drop surface <NUM>, the excess material <NUM> between the rough surface <NUM> and the circular cross sectional shape <NUM> is intended to be removed in order to develop the circular cross sectional shape <NUM> intended for the channel <NUM> in finished form. Further, while only the rough surface <NUM> and the tear drop surface <NUM> are described above, the disclosure contemplates other surfaces or regions of the channel <NUM> defining undesirable distortions (whether or not intentionally placed) or regions of undesirable surface roughness (e.g., where a rough surface <NUM> extends along the tear drop surface <NUM> or some other down-facing surface) or various combinations thereof. In various embodiments, the up-facing surface <NUM> is characterized by a surface roughness substantially less than that of the down-facing surface <NUM>, thereby enabling the up-facing surface <NUM> to serve as a stabilizing platform for guiding a cutter through the channel <NUM>, the cutter being configured to remove the excess material <NUM> along a length of the channel <NUM>.

Referring now to <FIG>, a cutting system <NUM> configured to remove excess material along a length of a channel, such as, for example, the excess material <NUM> along the length of the channel <NUM> described above with reference to <FIG>, is illustrated. The cutting system <NUM> includes a cutter base <NUM> and a cutter head <NUM> attached to the cutter base <NUM>. The cutter head <NUM> includes a cutter blade <NUM>. The cutter blade <NUM> may be configured to remove the excess material as the cutter head <NUM> rotates within the channel. A drive cable <NUM> extends between a rotary driver <NUM> (e.g., a motor or gear assembly connected to a motor) and the cutter base <NUM> and is configured to impart a rotary motion or a torque from the rotary driver <NUM> to the cutter head <NUM>. In various embodiments, the rotary driver <NUM> is configured to impart the rotary motion in a single rotary direction <NUM> (e.g., in a continuous rotary direction with respect to an axis through the drive cable <NUM>) or in a dual rotary direction <NUM> (e.g., in a washing machine like, back and forth direction with respect to the axis through the drive cable <NUM>). In various embodiments, the dual rotary direction <NUM> is configured to focus cutting of the excess material proximate a down-facing surface without cutting material proximate an up-facing surface. The single rotary direction <NUM> may be configured to cut material from both the down-facing surface and the up-facing surface.

Still referring to <FIG>, in various embodiments, the cutting system <NUM> includes a fulcrum <NUM> disposed at an upstream location of the cutter head <NUM> (assuming the cutter head <NUM> progresses in a downstream direction while cutting) and configured to stabilize and position the cutter base <NUM> and the cutter head <NUM> within the channel. The fulcrum <NUM> includes a fulcrum outer surface <NUM> configured for positioning against an interior surface of the channel following one or both of the down-facing surface and the up-facing surface being cut by the cutter head <NUM>. In various embodiments, the fulcrum <NUM> further includes a hollow portion <NUM> configured to receive the drive cable <NUM> along a length of the fulcrum <NUM>. The hollow portion <NUM> may be configured to grip the drive cable <NUM>, such that the fulcrum <NUM> is driven in a rotary direction together with the cutter head <NUM>, or the hollow portion <NUM> may be oversized with respect to the drive cable <NUM>, such that the fulcrum <NUM> does not rotate. In both instances, the fulcrum <NUM> is typically disposed at a distance <NUM>, which may be fixed or variable, sufficient to stabilize the cutter head <NUM> within the channel. Further, in various embodiments, one or both of the fulcrum outer surface <NUM> and a cutter base outer surface <NUM> may have a substantially cylindrical shape, as illustrated, or a rounded shape (depicted by the dashed lines in <FIG>). In various embodiments, the rounded shape may be characterized by a sphere <NUM> or by a cylinder having rounded ends <NUM> or by various other bodies of revolution in between the two, such as, for example, a football shape. In various embodiments, use of a flexible material in constructing the drive cable <NUM> will enable the cutting system <NUM> to navigate curved channels using the up-facing surface as a guide surface. Note that while <FIG> illustrate the presence of the fulcrum <NUM> configured to stabilize and position the cutter base <NUM> and the cutter head <NUM> within the channel, in various embodiments, the fulcrum <NUM> may be eliminated from the cutting system <NUM>.

Referring now to <FIG>, a cutting system <NUM>, configured to remove excess material along a length of a channel, such as, for example, the excess material <NUM> along the length of the channel <NUM> described above with reference to <FIG>, is illustrated. The cutting system <NUM> includes a cutter base <NUM> and a cutter head <NUM> attached to the cutter base <NUM>. The cutter head <NUM> includes a cutter blade <NUM>. The cutter blade <NUM> may be configured to remove the excess material as the cutter head <NUM> rotates within the channel. A drive cable <NUM> extends between a rotary driver <NUM> (e.g., a motor or gear assembly connected to a motor) and the cutter base <NUM> and is configured to impart a rotary motion or a torque from the rotary driver <NUM> to the cutter head <NUM>. In various embodiments, the rotary driver <NUM> is configured to impart the rotary motion in a single rotary direction <NUM> (e.g., in a continuous rotary direction with respect to an axis through the drive cable <NUM>) or in a dual rotary direction <NUM> (e.g., in a washing machine like, back and forth direction with respect to the axis through the drive cable <NUM>). In various embodiments, the dual rotary direction <NUM> is configured to focus cutting of the excess material proximate a down-facing surface without cutting material proximate an up-facing surface. The single rotary direction <NUM> may be configured to cut material from both the down-facing surface and the up-facing surface, though, in various embodiments, the single rotary direction <NUM> may likewise be configured to focus cutting of the excess material proximate the down-facing surface without cutting material proximate the up-facing surface.

In various embodiments, the cutting system <NUM> may include one or more directional cables <NUM> (or a directional cable), such as, for example, a first directional cable <NUM>, a second directional cable <NUM> and a third directional cable <NUM>. The one or more directional cables <NUM> are configured to direct the cutter head <NUM> through the channel and to focus the cutting action of the cutter head <NUM> on, for example, the excess material existing proximate a down-facing surface of the channel. In various embodiments, the rotary driver <NUM> is configured to impart a sinusoidal push-pull action against the one or more directional cables <NUM> such that the cutter blade <NUM> is urged against the down-facing surface and is urged away from the up-facing surface. For example, during the single rotary direction <NUM> mode of operation, the first directional cable <NUM> may be pulled toward the rotary driver <NUM> when proximate the down-facing surface, while the second directional cable <NUM> and the third directional cable <NUM> are pushed away from the rotary driver <NUM>. Similarly, the first directional cable <NUM> may be pushed away from the rotary driver <NUM> while proximate the up-facing surface, while the second directional cable <NUM> and the third directional cable <NUM> are pulled toward the rotary driver <NUM>. The push-pull action of the one or more directional cables <NUM> just described ensures only the region of excess material is removed, while leaving the relatively smooth up-facing surface undisturbed by the cutter blade <NUM>. The sinusoidal push-pull action also ensures a smooth transition as the cutter blade <NUM> passes between the down-facing surface to the up-facing surface or between various rough surfaces requiring cutting and relatively smooth surfaces that do not benefit from cutting. Further, the sinusoidal push-pull action is applicable to either the single rotary direction <NUM> mode of operation or the dual rotary direction <NUM> mode of operation. Note that while the push-pull action described above is beneficial in cutting the down-facing surface while leaving the up-facing surface substantially uncut, the disclosure contemplates the push-pull action being configured, in various embodiments, to cut both the down-facing surface and at least some or all of the up-facing surface as well. Cutting some or all of the up-facing surface may prove beneficial in various situations, particularly where there exist large distortions of the component or where a portion of the channel is required to me moved to a specific location relative to a reference location following the additive manufacturing process.

Still referring to <FIG>, in various embodiments, the cutting system <NUM> includes a fulcrum <NUM> disposed at an upstream location of the cutter head <NUM> (assuming the cutter head <NUM> progresses in a downstream direction while cutting) configured to stabilize and position the cutter base <NUM> and the cutter head <NUM> within the channel. The fulcrum <NUM> includes a fulcrum outer surface <NUM> configured for positioning against an interior surface of the channel following one or both of the down-facing surface and the up-facing surface being cut by the cutter head <NUM>. In various embodiments, the fulcrum <NUM> further includes a primary hollow portion <NUM> configured to receive the drive cable <NUM> along a length of the fulcrum <NUM>, as well as a secondary hollow portion <NUM> corresponding to each of the one or more directional cables <NUM>. In various embodiments, the primary hollow portion <NUM> is configured to grip the drive cable <NUM>, such that the fulcrum <NUM> is driven in a rotary direction together with the cutter head <NUM>. Similarly, in various embodiments, the secondary hollow portion <NUM> corresponding to each of the one or more directional cables <NUM> is configured to grip each of the one or more directional cables <NUM> such that they also rotate together with the cutter head <NUM>. In various embodiments, each of the one or more directional cables <NUM> is configured to slide within the secondary hollow portion <NUM> that corresponds to each such directional cable to enable the sinusoidal push-pull action described above. Further, in various embodiments, one or both of the fulcrum outer surface <NUM> and a cutter base outer surface <NUM> may have a substantially cylindrical shape, as illustrated, or a rounded shape, similar to any of the rounded shapes described above with reference to <FIG>.

In various embodiments, the cutting system <NUM> may include one or more directional cables <NUM> (or a directional cable), such as, for example, a first directional cable <NUM>, a second directional cable <NUM> and a third directional cable <NUM>. The one or more directional cables <NUM> are configured to direct the cutter head <NUM> through the channel and to focus the cutting action of the cutter head <NUM> on, for example, the excess material existing proximate a down-facing surface of the channel. In various embodiments, the rotary driver <NUM> is configured to impart a sinusoidal push-pull action against the one or more directional cables <NUM> such that the cutter blade <NUM> is urged against the down-facing surface and is urged away from the up-facing surface, in a manner similar to that described above with reference to <FIG>.

Still referring to <FIG>, in various embodiments, the cutting system <NUM> includes a fulcrum <NUM> disposed at an upstream location of the cutter head <NUM> (assuming the cutter head <NUM> progresses in a downstream direction while cutting) configured to stabilize and position the cutter base <NUM> and the cutter head <NUM> within the channel. The fulcrum <NUM> includes a fulcrum outer surface <NUM> configured for positioning against an interior surface of the channel following one or both of the down-facing surface and the up-facing surface being cut by the cutter head <NUM>. In various embodiments, the fulcrum <NUM> further includes a primary hollow portion <NUM> configured to receive the drive cable <NUM> along a length of the fulcrum <NUM>, as well as a secondary hollow portion <NUM> corresponding to each of the one or more directional cables <NUM>. In various embodiments, the primary hollow portion <NUM> is oversized with respect to the drive cable <NUM> such that the fulcrum <NUM> does not rotate. Similarly, in various embodiments, the secondary hollow portion <NUM> corresponding to each of the one or more directional cables <NUM> is oversized with respect to the one or more directional cables <NUM> such that they are configured to slide within the secondary hollow portion <NUM> that corresponds to each such directional cable to enable the sinusoidal push-pull action described above. Further, in various embodiments, one or both of the fulcrum outer surface <NUM> and a cutter base outer surface <NUM> may have a substantially cylindrical shape, as illustrated, or a rounded shape, similar to any of the rounded shapes described above with reference to <FIG>.

Referring more specifically to <FIG>, the cutter base <NUM> is configured to rotate with respect to a cutter pedestal <NUM> that is itself connected to each of the one or more directional cables <NUM>. A bearing assembly <NUM> may be disposed between the cutter base <NUM> and the cutter pedestal to facilitate the relative rotation between the two components. The drive cable <NUM> extends through an oversized hollow portion <NUM> within the cutter pedestal <NUM> and into the cutter base <NUM>, gripping the cutter base <NUM> such that as the drive cable <NUM> rotates, the cutter pedestal remains stationary with respect to the drive cable <NUM>, while the cutter base <NUM> rotates along with the drive cable <NUM>, together with the cutter head <NUM> and the cutter blade <NUM>. In various embodiments, the one or more directional cables <NUM> are configured to direct the cutter head <NUM> through the channel via the push-pull action described above working against the cutter pedestal <NUM>, rather than the cutter base <NUM>. This configuration facilitates rotation of only the cutter base <NUM> and the cutter head <NUM>, via rotation of the drive cable <NUM>, while the fulcrum <NUM> and each of the one or more directional cables <NUM> remain rotationally stationary with respect to the drive cable <NUM>.

Referring now to <FIG> which fall outside the scope of the claims, a cutting system <NUM>, configured to remove excess material along a length of a channel, such as, for example, the excess material <NUM> along the length of the channel <NUM> described above with reference to <FIG>, is illustrated. In embodiments that fall outside the scope of the claims, the cutting system <NUM> includes a cutter base <NUM> and a cutter head <NUM>. Similar to the embodiment described above with reference to <FIG>, the cutter head <NUM> is rotatably attached to a cutter pedestal <NUM>. The cutter pedestal <NUM> is attached to the cutter base <NUM> via a hinge, which, in various embodiments, may include one or both of a first hinge <NUM> and a second hinge <NUM>. The cutter head <NUM> includes a cutter blade <NUM>. The cutter blade <NUM> may be configured to remove the excess material as the cutter head <NUM> rotates within the channel. A drive cable <NUM> extends between a rotary driver (e.g., a motor or gear assembly connected to a motor) and the cutter head <NUM> and is configured to impart a rotary motion or a torque from the rotary driver to the cutter head <NUM>. In various embodiments, the rotary driver is configured to impart the rotary motion in either the single rotary direction or the dual rotary direction as described elsewhere above.

In embodiments that fall outside the scope of the claims, the first hinge <NUM> and the second hinge <NUM> are configured to move or transition the cutter head <NUM> between a cutting configuration (as illustrated in <FIG>) and a non-cutting configuration (as illustrated in <FIG>). A cable <NUM> includes a first end <NUM> connected to the cutter pedestal <NUM> and a second end <NUM> connected to an actuator <NUM>. The actuator <NUM> is configured to urge the cutting system <NUM> into the cutting configuration by pulling on the cable <NUM>, thereby urging the cutter pedestal <NUM> toward the cutter base <NUM>, such that the first hinge <NUM> and the second hinge <NUM> force the cutter head <NUM>, rotatably attached to the cutter pedestal <NUM>, to be offset from the cutter base <NUM> by a cutting distance <NUM>. The actuator <NUM> is configured to allow the cutting system <NUM> to return to the non-cutting configuration by releasing the cable <NUM>, thereby allowing the cutter pedestal <NUM> to move away from the cutter base <NUM>, such that the first hinge <NUM> and the second hinge <NUM> force the cutter head <NUM> back into alignment with the cutter base <NUM>, reducing the cutting distance <NUM> back to a nominal value (e.g., a value of zero). A spring <NUM> may be disposed within or proximate the cutter base <NUM> to urge the cutter pedestal <NUM> and the cutter head <NUM> away from the cutter base <NUM> upon release of the cable <NUM> by the actuator <NUM>. In various embodiments, one or both of the cutter base <NUM> and the cutter pedestal <NUM> may include one or more rollers <NUM> configured to slide against an interior surface of the channel (e.g., an up-facing surface) to stabilize or guide the cutting system <NUM> while in either the cutting configuration or the non-cutting configuration.

Referring now to <FIG>, a cutting system <NUM>, configured to remove excess material along a length of a channel, such as, for example, the excess material <NUM> along the length of the channel <NUM> described above with reference to <FIG>, is illustrated. The cutting system <NUM> includes a cutter base <NUM> and a cutter head <NUM> attached to the cutter base <NUM>. The cutter head <NUM> includes a cutter blade <NUM>. The cutter blade <NUM> may be configured to remove the excess material as the cutter head <NUM> rotates within the channel. A drive cable <NUM> extends between a rotary driver (e.g., a motor or gear assembly connected to a motor) and the cutter base <NUM> and is configured to impart a rotary motion or a torque from the rotary driver to the cutter head <NUM>. In various embodiments, the rotary driver is configured to impart the rotary motion in either the single rotary direction or the dual rotary direction as described elsewhere above.

In various embodiments, a housing <NUM> includes a first end <NUM> configured to provide a contact or support surface for the cutter base <NUM> while the cutting system <NUM> assumes a cutting configuration (as illustrated in <FIG>) and to provide a no contact or support surface for the cutter base <NUM> while the cutting system <NUM> assumes a non-cutting configuration (as illustrated in <FIG>). The housing <NUM> also includes second end <NUM> that may be connected to an actuator <NUM> (or to some other suitable support structure) configured to place an axial load on the drive cable <NUM> while the cutting system <NUM> assumes the cutting configuration and to release the axial load while the cutting system <NUM> assumes the non-cutting configuration. Placing the axial load on the drive cable <NUM> causes the cutter base <NUM> to engage the first end <NUM> of the housing <NUM>, thereby supporting the cutter head <NUM> and the cutter blade <NUM> while cutting an interior surface of the channel. Releasing the axial load on the drive cable <NUM> allows the cutter base <NUM> to move a distance <NUM> away from the first end <NUM> of the housing <NUM>, thereby releasing support for the cutter head <NUM> and the cutter blade <NUM>, rendering cutting of the interior surface ineffective. In various embodiments, the housing <NUM> may rotate with the drive cable <NUM> or remain stationary with respect thereto.

Referring now to <FIG>, a method <NUM> of removing excess material along a down-facing surface of a channel constructed using an additive manufacturing process is described. In various embodiments, a first step <NUM> includes rotating a cutter blade within the channel having an up-facing surface and a down-facing surface. A second step <NUM> includes guiding the cutter blade along a length of the channel using the up-facing surface of the channel to stabilize the cutter blade. A third step <NUM> includes urging the cutter blade toward the down-facing surface to remove the excess material as the cutter blade traverses the channel. A fourth step <NUM> includes urging the cutter blade away from the up-facing surface as the cutter blade traverses the channel. In various embodiments, urging the cutter blade toward the down-facing surface and urging the cutter blade away from the up-facing surface includes applying a push-pull action against a directional cable coupled to the cutter blade. In various embodiments, urging the cutter blade toward the down-facing surface comprises transitioning the cutter blade toward a cutter base via a hinge and urging the cutter blade away from the up-facing surface comprises transitioning the cutter blade away from the cutter base via the hinge.

The foregoing disclosure provides apparatus and methods that enable greater design freedom in finishing internal passages or channels disposed within components made using additively manufacturing techniques. The apparatus and methods, in particular, facilitate enhanced uniformity and precision of the channels during finishing processes subsequent to initial fabrication of components via an additive manufacturing process.

In the detailed description herein, references to "one embodiment", "an embodiment", "various embodiments", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic.

As used herein, the terms "comprises", "comprising", or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Claim 1:
A cutting system (<NUM>; <NUM>; <NUM>; <NUM>) for removing an excess material (<NUM>) along a length of a channel (<NUM>) constructed using an additive manufacturing process, comprising:
a cutter head (<NUM>; <NUM>; <NUM>; <NUM>);
a cutter blade (<NUM>; <NUM>; <NUM>; <NUM>) attached to the cutter head (<NUM>; <NUM>; <NUM>; <NUM>);
a drive cable (<NUM>; <NUM>; <NUM>; <NUM>);
a rotary driver (<NUM>; <NUM>; <NUM>); and
a cutter base (<NUM>; <NUM>; <NUM>; <NUM>) connected to the cutter head (<NUM>; <NUM>; <NUM>; <NUM>) and having a cutter base outer surface (<NUM>; <NUM>; <NUM>) configured to contact an internal surface within the channel to guide the cutter blade against the excess material,
characterised in that the drive cable (<NUM>; <NUM>; <NUM>; <NUM>) extends between the rotary driver (<NUM>; <NUM>; <NUM>) and the cutter base (<NUM>; <NUM>; <NUM>; <NUM>) such that the cutter base (<NUM>; <NUM>; <NUM>; <NUM>) rotates along with the drive cable (<NUM>; <NUM>; <NUM>; <NUM>), together with the cutter head (<NUM>; <NUM>; <NUM>; <NUM>) and in that the drive cable (<NUM>; <NUM>; <NUM>; <NUM>) is configured to impart a rotary motion from the rotary driver (<NUM>; <NUM>; <NUM>) to the cutter head (<NUM>; <NUM>; <NUM>; <NUM>).