WO2024105631A1

WO2024105631A1 - Metal depositing system and method for additive metal casting

Info

Publication number: WO2024105631A1
Application number: PCT/IB2023/061644
Authority: WO
Inventors: Gil Lavi; Ofer TEVET; Emil Weisz; Shimon Sandik
Original assignee: Magnus Metal Ltd.
Priority date: 2022-11-18
Filing date: 2023-11-17
Publication date: 2024-05-23
Also published as: WO2024105632A1

Abstract

A metal deposition system (500), casting system and methods for molten-metal additive casting on one or more build tables, comprising (a) one or more stationary input metal reservoirs (501) configured to contain solid input metal and allocate movable-doses of the solid input metal; (b) one or more intermediate stages (502) having at least an actuator configured to convey a movable dose of the solid input metal allocated from the stationary reservoir; (c) one or more deposition modules (503) configured to receive a deposition-session dose of the solid input metal from the intermediate stage, and to deposit molten metal; (d) one or more travel modules (524) for traveling over the one or more build tables at least one of: the one or more deposition modules and the one or more intermediate stages; wherein the deposition module is configured to perform heating of at least a portion of the deposition-session dose of the solid input metal to a deposition temperature. The system may further comprise a controller for controlling the intermediate stage, the one or more deposition modules, the one or more travel modules and, optionally, the one or more stationary input metal reservoirs, for preparing the input metal for deposition, and wherein preparing the input metal for deposition comprises at least one of: positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate.

Description

METAL DEPOSITING SYSTEM AND METHOD FOR ADDITIVE METAL CASTING

FIELD OF THE DISCLOSED TECHNIQUE

The present invention relates to metal devices, systems, and methods for the additive casting of metals. More particularly, the present invention relates to a metal device, system, and method for controllable deposition of molten metal for additive metal casting.

SUMMARY OF THE DISCLOSED TECHNIQUE

According to a metal deposition aspect of the present disclosure, there is provided a metal deposition system for molten-metal additive casting on one or more build tables, comprising (a) one or more stationary input metal reservoirs configured to contain solid input metal and allocate movable-doses of the solid input metal; (b)one or more intermediate stages having at least an actuator configured to convey a movable dose of the solid input metal allocated from at least one of the one or more stationary reservoirs; (c) one or more deposition modules configured to receive a depositionsession dose of the solid input metal from the intermediate stage, and to deposit molten metal; (d) one or more travel modules for traveling over the one or more build tables at least one of: the one or more deposition modules and the one or more intermediate stages; wherein the one or more deposition modules are configured to perform heating of at least a portion of the deposition-session dose of the solid input metal to a deposition temperature.

The metal deposition system may further comprise a controller for controlling the one or more intermediate stage, the one or more deposition modules, the one or more travel modules and, optionally, the one or more stationary input metal reservoirs, for preparing the input metal for deposition, and wherein preparing input metal for deposition comprises at least one of: positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate.

The controller may be configured to control the one or more travel modules to travel the one or more deposition modules along a deposition path. The controller may be further configured to control a position of at least the portion of the deposition-session dose of the solid input metal above the deposition path.

The one or more intermediate stages may further comprise one or more movable metal-dose reservoirs.

The one or more deposition modules may comprise a material addition mechanism configured to add additives and/or inoculants to the molten metal for adjusting metal properties, and the controller may be configured to control an inoculation mechanism. The controller may be configured to control the inoculation mechanism to add the additives and/or inoculants to the molten metal at least at one of (1) before molten metal deposition, (2) during molten metal deposition and (3) after molten metal deposition.

The solid input metal may comprise metal pieces having predetermined shape, size, and weight, and the one or more stationary input metal reservoirs are configured to allocate a predetermined number of metal pieces; the one or more intermediate stages may be configured to receive and convey a predetermined number of the metal pieces allocated from the stationary input metal reservoirs; the one or more deposition modules may be configured to receive at least one metal piece from the one or more intermediate stages and to deposit molten metal in selected deposition locations in the one or more build tables; and the one or more deposition modules may comprise a melting module for melting a portion of the metal piece. The at least one metal piece may be two or more metal pieces and the two or more metal pieces may be metal rods.

The metal pieces may comprise at least two metal pieces having differing properties. The controller may control which metal piece is received by the deposition module. The controller may be configured to control which metal piece is received by the deposition module as a function of the deposition path.

The controller may be configured to control the one or more travel modules to travel at least one of the intermediate stages and the deposition module for deposition dose replenishment and to travel the deposition module along a deposition path. The deposition module may be physically coupled to the intermediate stage and movable therewith. At least one of the deposition modules and the intermediate stage may comprise a metal piece magazine configured to contain the predetermined number of metal pieces.

The controller may be configured to control the one or more travel modules to travel the deposition module to and from the one or more intermediate stages and to travel the deposition module along a deposition path.

At least one of the intermediate stages and the deposition module comprises a metal piece applicator configured to replace a partially melted metal piece with a new metal piece. The metal piece applicator may be configured to unload a previously allocated metal rod from the deposition module. The new metal piece may have different properties than the partially-melted metal piece, and the controller may control the replacement as a function of the deposition path.

At least one of the deposition modules and the intermediate stage comprise a movable metal piece holder for holding the metal piece and the controller may be further configured to control the movable metal piece holder to maintain a predetermined height between the portion of the metal piece and the melting module.

The deposition module may further comprise one or more shaft heaters configured to heat the molten metal after melting and before arrival to a selected deposition location.

The deposition module may further comprise one or more area heaters configured to heat a working area in the selected deposition locations. The controller may be further configured to control the area heaters to heat the working area at least one of: before metal deposition, during metal deposition and after metal deposition.

The controller may control one or more parameters selected from the list including: (a) the transport speed of the movable metal-dose reservoir of the one or more intermediate stages; (b) the travel speed of the deposition module; (c) the movable-dose transferring rate to the movable metal-dose reservoir; (d) melting rate of the melting module; (e) deposition rate of the deposition module; (f) temperature of the metal in the deposition module; (g) temperature of the metal in the movable metaldose reservoir; (h) deposition progress along a deposition path over the build plane; (i) distance between adjacent deposition path lines over the build plane; and (j) height between the portion of the deposition-session dose of the solid input metal and the melting module.

The metal deposition system may comprise sensors indicative of at least one parameter selected from the group consisting of (a) temperature of metal incoming to the deposition module; (b) temperature of molten metal outgoing from the deposition module right before depositing in the build plane; (c) volume orflow rate of molten metal incoming to a descent path; (d) volume or flow rate of molten metal outgoing from the descent path; (e) liquid height of molten metal in a crucible or pool; and (f) height between the portion of the deposition-session dose of the solid input metal and the melting module, and the controller may be responsive to readings of the sensors for controlling one or more of the parameters.

The metal deposition system may further comprise an application depositor which is configured to receive molten metal from the deposition module, heat the molten metal to an additive-casting-temperature, and drip, drop, drizzle, trickle, flow, or stream molten metal to a selected location for depositing.

The metal deposition system may further comprise a deposition dose protection unit and the controller is further configured to control the deposition dose protection unit for maintaining at least a portion of a metal deposition dose in an inert environment at least during metal melting and molten metal deposition.

According to another aspect of the present disclosure, there is provided a casting system for casting a metallic object by constructing a plurality of production layers forming a vertical stack, wherein production layers of the plurality have mold regions, wherein production layers of the plurality have object regions defined by the mold regions, and wherein a current production layer is constructed upon a top surface of a previous production layer of the vertical stack, the casting system comprising: a mold construction system operative to construct a mold region of the current production layer; a metal deposition system operative to construct an object region of the current production layer; a build table, for supporting the vertical stack of production layers; and a controller for controlling at least the mold construction system and the metal deposition system, wherein the metal deposition system is the metal deposition system discussed above regarding the metal deposition aspect of the present disclosure.

According to yet another aspect of the present disclosure, there is provided a metal deposition method for additive casting, comprising the operations of: (a) allocating movable-doses of solid metal contained in a stationary input metal reservoir to an intermediate stage having at least an actuator and receiving a movable-dose in the intermediate stage; (b) conveying, by the intermediate stage, the movable dose of solid metal over one or more build tables; (c) receiving solid metal from the movable metaldose reservoir and depositing molten metal; (d) depositing, by a deposition module, the metal in a form of molten metal at a deposition temperature in selected deposition locations in the one or more build tables; and (f) controlling, by a controller, at least the one or more stationary input metal reservoirs, the intermediate stage, and the one or more travel modules for preparing the solid metal for deposition, wherein preparing the solid metal for deposition comprises at least one of: positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate; and wherein the deposition module is configured to perform at least one of the positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate.

The movable-doses of metal may be a predetermined number of metal pieces having predetermined shape, size, and weight contained in a stationary input metal reservoir; the intermediate stage may be a movable metal-piece reservoir; the deposition module may receive at least one metal piece from the movable metal-piece reservoir; the method further comprises melting, by a melting module accommodated in deposition module, a portion of the metal piece; and controlling, by a controller, at least the one or more stationary input metal reservoirs, the movable metal-piece reservoir and the deposition module for depositing molten metal in selected deposition locations in the one or more build tables.

The method may further comprise controlling a metal piece holder accommodated in one of the intermediate stages and the deposition module to maintain a predetermined height between the portion of the metal piece and the melting module. The metal deposition method may further comprise controlling, by the controller, one or more parameters selected from the list including: (a) transport speed of the movable metal-piece reservoir; (b) travel speed of deposition module of the intermediate stage; (c) melting rate of the melting module; (d) deposition rate of the deposition module; (e) temperature of the metal in the deposition module; (f) temperature of the metal in the movable metal-piece reservoir; (g) temperature of metal incoming to the deposition module; (h) deposition progress along a deposition path over the build plane; (i) distance between adjacent deposition path lines over the build plane; and (j) height between the portion of a deposition-session dose of a solid input metal and the melting module.

The metal deposition method may further comprise controlling one or more of the parameters by a controller responsive to readings of sensors indicative of at least one parameter selected from the one or more of the parameters consisting of: (a) temperature of molten metal outgoing from the deposition module; (b) temperature of molten metal right before depositing in the build plane; (c) volume or flow rate of molten metal outgoing from the deposition module; (d) speed of the deposition module along the deposition path; and (e) height between the portion of the deposition-session dose of the solid input metal and the melting module.

Another aspect of the invention is a metal deposition system for molten- metal additive casting on one or more build tables, comprising (a) one or more stationary input metal reservoirs configured to contain solid input metal and allocate movable-doses of the solid input metal; (b) one or more movable metal-dose reservoirs configured to convey a movable-dose of metal allocated from the stationary reservoir; (c) one or more deposition modules configured to receive a depositionsession dose of the solid input metal from the intermediate stage, and to deposit molten metal; (d) one or more travel modules for traveling over the one or more build tables at least one of: the one or more deposition modules and the one or more intermediate stages; wherein the deposition module is configured to perform heating to a deposition temperature, and optionally to adjust material properties, and/or set a deposition rate.

The metal deposition method may further comprise containing in a crucible and heating metal lingering therein in a molten state, wherein the crucible is placed in the deposition module. The controller may be further configured to control the temperature of molten metal in the crucible and/or the height of the molten metal in the crucible. The controller may be further configured to control a flow of molten metal lingering out of the crucible.

The metal deposition method may further comprise adding additives and/or inoculants to the molten metal. The additives and/or inoculants may be added to the molten metal before molten metal deposition, during molten metal deposition or after molten metal deposition.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed techniques will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which:

Figure 1 is a schematic illustration depicting an embodiment constructed and operative in accordance with the present disclosure featuring principal components;

Figure 2 depicts a system arrangement that exemplifies several options for implementing embodiments constructed and operative in accordance with the present disclosure;

Figure 3A is a schematic block diagram of a casting system, and Figure 3B conceptually illustrates a production floor plan of an example of a casting system, employing the metal deposition system according to embodiments of the present disclosure;

Figures 4, 5A-5B are schematic illustrations of metal deposition systems according to other embodiments of the invention;

Figure 6 a is a conceptual illustration of a rod load manipulator operational for advancing a horizontally disposed metal rod in accordance with embodiments of the invention;

Figure 7 is a cross-sectional illustration of a plunger crucible constructed and operative in accordance with embodiments of the present disclosure, featuring start/stop and flow control; Figures 8 and 9 are flow charts of methods for additive metal casting operative in accordance with embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In traditional casting, molten metal deposition involves a single-shot discharge of molten metal into a fully-fabricated mold, preferably as fast as possible. Molten metal flow is often designed to overcome flow obstacles associated with holes, windows, and additional metal cast features. However, for additive casting, according to embodiments of the invention, the discharge of molten metal in a controlled manner is required. The metal (or metallic) object is fabricated in a series of production layer fabrication operations carried out on a build table. In each production layer, a mold region (e.g. one or more mold layers) is first fabricated. Upon completion of the mold region (e.g. the mold layer/s) of the current production layer - the object region is fabricated by depositing molten metal into the mold region. Thus, molten metal is deposited in a cyclic manner. A certain amount of time -the time needed for mold region construction - lapses between one molten metal deposition in one production layer and the successive molten metal deposition in the subsequent production layer. The production environment - the build table and the previously produced production layers, experience a cyclic thermal regime: the production temperature of the mold regions may differ from the production temperature of the object regions.

It is an object of the present disclosure to provide metal devices, systems, and methods for effectively manufacturing metal objects by additive casting with molten metal using solid metal as metal input. Metal rods, bars, billets with pre-determined weight, shape, and metal properties, as well as scrap, may be used. The invention is not limited by the type of solid metal input. Any metallic material that can be melted or otherwise liquefied may be used with the required modifications.

Examples of metallic materials that may be used are metals and alloys, for example, grey iron, ductile iron, steel, Inconel, titanium alloys, cast iron alloys, and the like.

It is another object of embodiments of the present invention to facilitate a fast and robust additive casting process by molten metal deposition, and in particular, to provide an agile, maneuverable deposition module, applicator, or depositor while maintaining its adequate feed by molten metal and to facilitate control of at least deposition position, pace or rate and temperature, and metal properties.

Embodiments of the invention allow controlling the position, deposition rate, and temperature of molten metal, as well as the mechanical and/or chemical and/or metallurgical properties of the molten metal independently from other parameters, as needed to ensure an improved or optimal process both in terms of quality (metallurgywise and geometrically) and in deposition throughput.

According to embodiments of the invention, the metal deposition system comprises multi-tier metal modules ending with a deposition module. The deposition module is advanced over a build plane (for example, one or more build tables), delivering molten metal of a desired specification (mechanical and/or chemical and/or metallurgical properties) to desired locations at a desired temperature and discharge rate.

According to another aspect of the invention there is provided a metal casting system for additive casting that incorporates a multi-tier metal deposition system. According to yet another aspect of the invention, there is provided a metal casting method for additive casting that incorporates operating a multi-tier metal deposition system.

Examples of systems and methods for additive casting with molten metal are illustrated in PCT patent applications publication numbers WO2019053712A1, W02023002468 and WO2022243921A1 assigned to the assignee of the present application, which are incorporated herein by reference.

A three-tier architecture: according to an aspect of the invention, there is provided a metal system constructed in a three-tier configuration - hierarchical tiers of metal retaining and allocating components: a first, stationary tier, a second, metalcarrying movable tier, and a third, deposition tier. The first tier features a stationary reservoir, the second tier features intermediate stages having at least an actuator, and the third tier features a deposition module.

The intermediate stage having at least an actuator of the second tier may, for example, be an arm, or other means which is configured to convey a piece of solid metal, for example, a rod, from the first tier to the third tier. Alternatively, the intermediate stage having at least an actuator may, for example, be or comprise, a movable metal-dose reservoir.

The intermediate stage may be configured to convey, for example, one or more pieces of solid metal from the first tier to the third tier.

The intermediate stage may be a movable metal-dose reservoir which is configured to convey a piece of solid metal, for example, a rod or a magazine of 2, 3, 4 rods and the like.

The three tiers may differ in several aspects: according to some embodiments, each tier is aimed at handling a different amount of metal. For example, the first tier handles the largest amount of metal (e.g. a first amount of metal); the second tier - the second tier may carry a smaller amount of metal (e.g. a second amount of metal) between the first tier and the deposition module; and the third tier - the deposition module - handles the smallest amount of metal (e.g. a third amount of metal), for example in a volume facilitating controllable heating and deposition and accurate positioning. For example, the additive metal depositing system may be configured with the stationary input metal reservoir containing metal in the range of 250-1000Kg, the intermediate stage accumulating metal in the range of 2.5-50Kg, while the deposition module configured to receive up to 1.5Kg of metal and to deposit metal at the pace or rate of up to lOcc/sec (or slower). According to some embodiments, which can be combined with other embodiments described herein, the first amount of metal is larger than the second amount of metal and the third amount of metal, particularly by at least a factor of 10. Optionally, in addition, the second amount of metal may be larger than the third amount of metal.

In one embodiment, the intermediate stage may carry the same amount of solid metal, which are handled by the deposition module. For example, the intermediate stage may carry only one piece of metal, for example, a metal rod, and the deposition module may handle only one piece of metal, for example, the same metal rod. In other embodiments, the intermediate stage may carry a reservoir of more solid metal than is handled by the deposition module. In the present disclosure, the expression "intermediate stage having at least an actuator" also encompasses the meaning of a movable metal-dose reservoir configured to convey a movable-dose of metal allocated from the stationary reservoir. In other words, the intermediate stage, having at least an actuator, may be a movable metal-dose reservoir configured to convey a movable-dose of metal allocated from the stationary reservoir.

For example, in case the input solid metal is in the form of metal rods ("rod use case"), the deposition module (tier 3) may carry a single rod; a stock of several tens or hundreds of rods forms the stationary reservoir (tier 1), and a rod load-unload unit with, e.g., a rod manipulation arm forms the intermediate stage (tier 2). In another example employing metal rods, the intermediate stage (tier 2) is realized as a 4-rod magazine with a load/unload actuator ("rod magazine use case"). The rod magazine may travel between the rod stock (tier 1) and the deposition module (tier 3). In yet another example ("wire use case"), the three-tier concept may apply to input solid metal in the form of a wire.

In some embodiments, the deposition module further comprises an application depositor in the form of a crucible located downstream to the rod, wire, or any other solid metal input. The application depositor is configured to receive molten metal dripping from, e.g., rod or wire, heat the molten metal to an additive-casting- temperature, and drip, drop, drizzle, trickle, flow, or stream molten metal to a selected location for depositing.

Accordingly, the stationary input metal reservoir (tier 1) is configured to contain, dispense, and allocate metal. The intermediate stage, having at least an actuator (tier 2), is configured to obtain solid metal allocated from the stationary reservoir for accumulating a dose of the metal, and may be configured for transporting the dose over a build plane, and transferring the dose of the solid metal. In the case that tier 2 is a movable metal-dose reservoir, the movable metal-dose reservoir may be configured to obtain solid metal allocated from the stationary reservoir for accumulating a dose of the metal, transporting the dose over a build plane, and transferring the dose of the solid metal. The deposition module is operational for receiving solid metal from the intermediate stage or movable metal-dose reservoir and for depositing the molten metal in selected locations in the build plane according to a building plan. The controller is operational for controlling at least the intermediate stage, having at least an actuator, and the deposition module for depositing the molten metal at a casting-ready temperature and at the desired rate.

For example, if the input metal is in the form of rods (the rod use case), the intermediate stage has at least an actuator, or the movable metal-dose reservoir of tier 2 may include an arm, or a rod holder. The arm, or the rod holder, may obtain a rod from the stationary input metal reservoir (tier 1), and transport the rod to the deposition module (tier 3). In the wire use case, the intermediate stage having at least an actuator, or the movable metal-dose reservoir, of tier 2 may include a wire spool loader/unloader.

The three-tier metal deposition system may be accommodated by an additive casting system and be operable therewith. Among other elements, the casting system comprises a building table defining a building plane over which the movable deposition module and, optionally, the intermediate stage travel. In some embodiments, the building table is assigned with one or more stationary reservoirs, one or more intermediate stages, and one or more deposition modules.

The three-tier architecture facilitates controllability, repeatability, and high throughput at industrial scaling of the casting process, particularly for vehicle components, truck components, train components, engine components, axles components, gear components, robotic components, heavy duty components and tooling components. The components can have a weight of 10 kg or above, such as 100 kg or above or even 1000 kg or above.

Also, in some embodiments, it is possible to combine or integrate tiers. In some embodiments, tiers 1 and 2 may be integrated. For example, the movable metaldose reservoir or intermediate stage may be coupled to, or mounted onto, the stationary input metal reservoir, and may include an arm that transfers doses of metal from the stationary input metal reservoir to the deposition module. For example, the arm could be a rotating actuator. The rotating actuator may have a first handler for the first rod and a second handler for the second rod. For example, the first handler may provide a new solid metal dose to the deposition module, and the second handler may remove a used solid metal dose from the deposition module. Particularly, the rotating actuator may remove and provide the solid metal dose at the same time and/or in one movement.

Alternatively, in some embodiments, tiers 2 and 3 may be integrated. For example, the deposition module may be coupled to or mounted onto the movable metaldose reservoir or intermediate stage. For example, in the rod magazine use case, the rod magazine (tier 2) - capable of carrying, e.g., 4 rods, is integrated with the deposition module and travels therewith. The deposition module is thus capable of depositing the metal of 4 rods before rod replenishment.

To increase casting throughput and improve footprint and cost-of- ownership, the additive casting system may include two or more building tables. In some embodiments, a single stationary input metal reservoir (tier 1) may serve two or more building tables. In some embodiments, two or more intermediate stages or movable metal-dose reservoirs are provided and serve the two or more building tables interchangeably. Additionally or alternatively, two or more deposition modules are provided and serve the two or more building tables, wherein a single stationary input metal reservoir and a single intermediate stage is provided.

The first tier is termed herein 'the stationary input metal reservoir'. The term 'stationary' indicates that while the second tier and third tier can move during the iterative deposition of metal into the object region of the multiple production layers - the first tier can essentially remain stationary during the deposition process. It should be understood that the input metal replenishment in the stationary input metal reservoir may or may not involve moving the stationary input metal reservoir. For example, the input metal may be fed into the stationary input metal reservoir by a crane (or any other load/unload system) lifting, e.g., a pile of metal billets or rods, with or without moving the stationary input metal reservoir toward the crane. In another example, the load/unload system may replace the stationary input metal reservoir as a whole.

Various solid input metal types may be used, such as rods, wires, billets, pebbles, ingots, ore, pig iron, and scrap. According to solid metal input aspects of the invention, metal preparation and, specifically, metal melting takes place in the deposition module. According to some embodiments, different preparation operations are distributed among the tiers. The preparation operations can be classified into four main preparation operations: (1) positioning; (2) temperature; (3) deposition flow rate; and (4) metal properties - mechanical, chemical, and metallurgical properties. The preparation operations may comprise, for example, volume and/or weight measurements and adjustments; chemical composition measurements and adjustments; mechanical properties measurements and adjustments; metallurgical properties measurements and adjustment; positioning; heating/cooling to a castingready temperature; deposition flow rate.

The preparation operations may be implemented using inter-alia, travel modules (e.g., robots), heating units (e.g., using induction heating), crucibles, and inoculants and additives. The three tiers may differ in the assignment and distribution of the preparation operations and, consequently, in their hardware configuration.

Solid metal is used as input, and the melting and, correspondingly, the optional use of inoculants and additives is assigned to tier 3. The invention is not limited by the type of inoculation mechanism that is used. Inoculation may be realized by air delivery.

The operations regarding positioning operation, metal properties, temperature, and flow rate control upon deposition are implemented mostly in the third tier on the smallest metal volumes, while some interim preparations may be handled in the first and second tiers on the larger metal volumes.

In yet another example, different measurements and assessments are performed in the various tiers, and corrective operations are implemented in response to the measurements and assessments. The corrective operations may be implemented in the same tier or in a downstream tier.

For example, the mechanical, chemical, and/or metallurgical properties of the input metal may be measured in the first tier, and in response, inoculants may be added in the third tier.

In the case that additives or inoculants are applied to the metal, the mechanisms for applying the additives or inoculants may be provided at tier 3. The additives or inoculants may be added to the object region surface before, concurrently with, or after the deposition of new molten metal.

The invention is not limited by the manner of additive or inoculant application.

In the case of air delivery, the additive or inoculant may be added in the form of gas-assisted powder distribution, and the powder feeding mechanism may comprise a powder dosing system and powder nozzle/s for shooting powder doses of additive or inoculant. In other embodiments, the additive or inoculant may be inoculant wire, inoculant block, or inoculant dispensing means. For example, the mechanism for applying the additive or inoculant in the form of a wire may comprise a wire feeder/injector and dispersion and mixing means for dispersing and mixing the additive or inoculant, e.g., in a crucible containing the molten metal before it is deposited.

The invention is not limited by the type of additives and inoculants that are used. For example, in the case of iron casting, alloys of silicon, manganese, copper, aluminum, strontium, and more can be used.

Embodiments of the disclosed invention harness different techniques for allowing a controlled, fast, and accurate deposition of molten metal for additive metal casting.

In some embodiments, the intermediate stage (having at least an actuator) (tier 2) and the deposition module (tier 3) are movable together. For example, the deposition module may be coupled to the movable metal-dose reservoir. In another example, the movement of the deposition module may be synchronized with the movement of the movable metal-dose reservoir. The deposition module may be integrated with the intermediate stage.

Solid metal input, melting at tier 3: in accordance with some aspects of the invention, the stationary input metal reservoir includes a solid input-metal feeder and an input metal dosage allocator for allocating the movable-dose in the form of a soliddosage portion of input metal to the intermediate stage having at least an actuator. The intermediate stage includes a deposition-session solid-dosage allocator for allocating a deposition-session solid-dosage portion from the movable-dose to the deposition module. The deposition module includes the melting module for melting the solid deposition-session solid-dosage portion for discharging as molten metal. The deposition module can further include a deposition molten metal buffer crucible, wherein the melting module melts the solid deposition-session solid-dosage portion for discharging as molten metal into the deposition molten metal buffer crucible.

In tier 3, one option for controlling the deposition rate of the molten metal is to use a plunger or to use a cascade of two or more crucibles, which will be described later.

Metal rods, and/or other metal pieces, that come in determined weights, shapes, and material properties may hierarchically constitute the second tier of the intermediate stage. By fetching a rod or a bar contained in the stationary metal input reservoir - a known amount of metal with known material properties (microstructure and other metallurgical properties, mechanical properties, chemical properties) is easily allocated by a robot, a magazine or any other unit designed to fit the predetermined shape and weight of the input metal piece.

The melting takes place at the third tier. The stationary reservoir comprises a rod station (rod stock, e.g., rods packed in a crate) for providing the reservoir with one or more rods. The deposition module may comprise a rod holder for holding the input rod. In some embodiments, an additional element-a rod magazine unit for holding more than a single rod is incorporated to thereby reduce the number and frequency of rod replenishment travels.

The solid metal may be one or more rods, bars, wires, ores, scrap, pig iron, or the like. Rods or bars can be advantageous in having fixed specifications, such as composition, cleanliness, etc. Rods and bars can also be advantageous in having a fixed weight and/or shape, and they can be easy to move and manipulate, for example, compared to pebbles, grains, scrap metal, etc. Ores or ingots can, in some cases, also have a well-determined specification and can be deposited as-is. Melting at tier 3 can be advantageous in terms of the balance between metal fabrication and mold construction. This is because, between metal deposition of consecutive layers, in some embodiments, the metal head may wait for the completion of the respective mold region (i.e. mold layer). Melting at tier 3 can provide 'on demand' melting, whereby it is not required to maintain a large stock of molten metal.

When using metal pieces such as rods as input, tier 2 may be integrated with the third tier.

Tier 3 - the deposition module: the deposition module receives solid metal in a small amount as input.

Travel and travel control, other control aspects, sensors: In accordance with some aspects of the invention, the metal deposition system further includes a travel module for traveling over the build plane at least one of: the deposition module, and the intermediate stage having at least an actuator. The deposition module and the intermediate stage may travel independently from each other or share a common travel unit.

The intermediate stage having at least an actuator may be a movable metaldose reservoir.

In accordance with some aspects of the invention, the controller controls one or more parameters selected from the list including: transport speed of the intermediate stage or movable metal-dose reservoir, travel speed of the deposition module, movabledose transferring rate to the intermediate stage or movable metal-dose reservoir, inoculants, and additive regime, deposition-session dose transferring rate to the deposition module, melting rate of the melting module, melt heating regime, the deposition rate of the deposition module, amount of material in the movable reservoir, amount of material in the deposition module, temperature of the metal in the deposition module, temperature of the metal in the intermediate stage or movable metal-dose reservoir, deposition progress along a deposition path over the build plane, and distance between adjacent deposition path lines over the build plane. In accordance with some aspects of the invention, the controller is configured to control the depositing of the molten metal at a controlled rate, by controlling one or more of: transporting speed of the intermediate stage or movable metal-dose reservoir, travel speed and direction of the deposition module, and deposition rate of the deposition module.

In accordance with some aspects of the invention, the controller is configured to control the start and stop of deposition during additive metal casting by controlling molten metal deposition by the deposition module.

In accordance with some aspects of the invention, the metal deposition system further includes sensors, indicative of at least one parameter selected from the group of: temperature of molten metal incoming to the deposition module, temperature of molten metal outgoing from the deposition module right before depositing in the build plane, volume or flow rate of molten metal incoming to the deposition module (for example, sensing and determining the drip count and/or width of stream), volume or flow rate of molten metal outgoing from the deposition module (for example, sensing and determining the drip count and/or width of stream), and liquid height of molten metal in a crucible or pool in tier 3, temperature of metal in the working areas (deposition locations) before additive casting, temperature of metal in the working areas (deposition locations) after additive casting, parameter of an additive, inoculant, or oxidationshielding in deposition location before additive casting, and parameter of an additive, inoculant, or oxidation-shielding in deposition location after additive casting, wherein the controller is responsive to readings of the sensors for controlling one or more of the parameters. The sensors may reside in a single tier (first, second, third) or distributed among the first, second, and third as needed.

Working area heating: In accordance with further aspects of the invention, the deposition module may be positioned in proximity to the working areas - the areas on which the molten metal is to be deposited. In some embodiments, additional heaters - working area heaters (also referred to as surface heaters) such as pre-deposition heater/s, area deposition heater/s, and/or post-deposition heater/s - may be placed in proximity to the working areas for providing pre-deposition heating, during-deposition heating, and/or post-deposition heating of the working areas (the surface of the object region currently produced) to thereby improve bonding and impact the metal cooling profile. In some embodiments, the working area heater/s may be physically and/or operably coupled to the deposition module as a separate melting-depositing-surface heating module. For example, the area heater/s may be carried by the travel unit that moves the deposition module over the build plane. In another example, the controller that controls the deposition temperature further controls the operation of the working area heater/s such that the control of the molten metal upon deposition will take into account the effect of all the heat sources operating in proximity to the working areas and the molten metal drops (or stream) upon deposition.

In accordance with some aspects of the invention, the working area heater/s includes at least one heating element encircling the deposition module over the build plane. In accordance with some aspects of the invention, the heating elements can be rotated about the deposition module.

Protective environment: In some embodiments, various parts of the metal deposition system further include a protective environment. For example, the deposition module may be provided with a tubular protective sleeve that includes, e.g., a single or double-walled funnel in which oxygen retarding gas (such as nitrogen or argon) is streamed for local purging. The tubular protective sleeve is placed between the deposition module and the working areas for shielding at least the molten metal to be deposited. In some embodiments, the tubular protective sleeve protects the melting zone of the deposition module. For example, in the rod use case, the tubular protective sleeve protects at least the bottom portion of the rod - the rod's tip and shoulder that undergo melting. In another example, if an application depositor is used, the application depositor crucible is also shielded by the tubular protective sleeve. Embodiments of the present disclosure including a 3 tier concept, particularly with melting at tier 3, allows to reduce or limit the space in which protective environment is provide for the casting system. Reference will now be made to the Figures, wherein like numbers denote like parts for clarity.

A three-tier molten metal deposition system for additive casting

Reference is now made to Figure 1, which is a partial, schematic illustration depicting an embodiment, denoted as metal deposition system 100, constructed and operative in accordance with embodiments of the invention featuring principal components. Metal deposition system 100 is operational for additive casting with molten metal over two build tables represented by perforated rectangles 102 and 104. Build tables 102 and 104 are used for additive casting, one production layer after another. Each production layer includes mold regions (not shown) defining object regions (not shown) into which molten metal is to be deposited. The first production layer may comprise only a mold region. After completing the production of the mold regions and object regions of a production layer - the production of the next layer starts. Each of build tables 102 and 104 defines a build plane per production layer. In each production layer, the mold region may be constructed by a mold constructing system (not shown). For example, the mold structure may be deposited in situ, by a mold deposition system (not shown). For another example, a plurality of layered mold structures is fabricated at a remote location (not shown), transferred to the build table, and constructed (not shown).

The additive casting system that incorporates the metal deposition system 100 may further comprise additional systems, elements, and components such as mold surface treatment elements, metal surface treatment elements, heaters, robots or other motion arrangements, inert gas elements, and additional elements (not shown).

The metal deposition system 100 is movable over the build plane (X-Y direction). The mold construction system and other systems and elements of the additive casting system are movable (not shown). The build table/s may be movable over the build plane (X-Y directions). The build table/s may be relatively movable in the Z direction with respect to the metal deposition system, the mold construction system, and other systems and elements of the additive casting system. A metal object and its respective mold structure (or more than a single cast) are then manufactured layer by layer on the build table/s. In the example of Figure 1, metal deposition system 100 includes a single stationary input metal reservoir 106, two intermediate stages 108 and 110, or movable metal-dose reservoirs, two deposition modules 112 and 114, and controller 116.

Stationary input metal reservoir 106 contains a large amount of metal and serves as a dispensing station to allocate metal doses to intermediate stages 108 and 110. Such doses are sometimes referenced herein as a "movable dose" or "movable metal dose". Intermediate stages 108 and 110, respectively, receive, accumulate the obtained doses, transport them over the build table 102, or 104, and respectively allocate and transfer, deliver or feed deposition-session doses (which may be smaller than the movable doses) to deposition modules 112 and 114, at desired paces or rates. Deposition modules 112 and 114, which receive deposition session doses of solid metal, deposit the metal in the form of molten metal in selected locations in respective build plane of build tables 102 or 104.

Controller 116 controls at least intermediate stage 108/110 and deposition module 112/114 for depositing the molten metal at a casting-ready temperature. The deposition module 112/114 comprises a melting module that is configured for melting solid metal into molten metal.

The metal deposition system 100 includes maneuvering means 118, 120, and 122. Intermediate stage 108 is movable by maneuvering means 118, and deposition module 112 is movable by maneuvering means 118.

According to embodiments of the invention, illustrated in build table 102, intermediate stage 108 and deposition module 112 are capable of moving independently of each other.

According to embodiments of the invention, illustrated in build table 104, the deposition module 114 is physically coupled to intermediate stage 110 and movable therewith. In Figure 1, intermediate stage 110 and deposition module 114 are coupled together in a single encasement 124 and, therefore, are movable by a single maneuvering means 122.

Controller 116 is connected to and operational for controlling the operation of stationary input metal reservoir 106, and the operation and movement of intermediate stages 108 and 110 and their respective maneuvering means 118 and 122, deposition module and its maneuvering means 120, and deposition module 114 (which is maneuvered together with intermediate stage 110 by maneuvering means 122).

The terms 'stationary' and 'movable' as used herein with respect to the stationary input metal reservoir 106, intermediate stages 108 and 110, and two deposition modules 112 and 114, are construed to describe the manner of operation of these elements for metal deposition during additive casting. For example, the stationary input metal reservoir 106 may be movable for input metal replenishment. For example, the stationary input metal reservoir 106 may independently maneuver or be rolled or lifted out of its place by another unit (not shown), refilled with input metal and returned to its place. The term "movable" as used herein, denotes that the intermediate stages 108 and 110 travel to and from the stationary input metal reservoir 106 for metal replenishment.

The three tiers differ from each other in their metal input replenishment regime. To illustrate, using a simplified, non-limiting example for the production of 500Kg. of gray iron per day using lOKg. rods as input metal, the stationary input metal reservoir may be construed to store several tens to hundreds of metal rods and be replenished once a day, or once in a few days. During casting, the intermediate stage may carry a single rod, two, four, or six rods (carry 10-60 Kg.) and may travel from a deposition location to the stationary input metal reservoir every 0.5-3 hours, while the metal input to the deposition module may be provided every 0.25 to 1.5 hours, depending on the specific system configuration. The deposition module travels over the build plane in a deposition path predefined by a building plan. The deposition module may travel over the build table for metal refill or stay on the deposition path and be served by the intermediate stage. Both the intermediate stage and the deposition module travel away from the build table after completing the fabrication of the object region in a production layer, for example, during mold region construction of the next production layer. Accordingly, metal conveyance considerations, for example, weight, accuracy, repeatability, efficiency, safety, timing, and production throughput, are relevant for designing the metal deposition system configuration and its operation.

Each tier may include a single-tier component or a multiplicity of tier components. For example, the first tier (tier 1) may include one or more stationary input metal reservoirs - a single-tier component is shown in Figure 1, serving both build tables. The transferring tier (tier 2) may include one or more intermediate stages (a single tier 2 component per build table is shown in Figure 1, but this is not necessarily so), and the deposition tier (tier 3) may include one or more deposition modules (a single tier 3 component per build table is shown in Figure 1, but this is not necessarily so).

Accordingly, each single-tier component can serve or be served by more than one component of another tier. For example, a stationary input metal reservoir can serve several intermediate stages, an intermediate stage can receive movable metal doses from several stationary input metal reservoirs and can serve to deliver depositionsession doses to several deposition modules, and a deposition module can be served by receiving deposition-session doses from several intermediate stages. An exemplary system may feature a single stationary input metal reservoir, which can serve two intermediate stages (allocating and delivering a metal dose to one intermediate stage at a time or to both at once), which serve the same deposition module (e.g., by alternately swapping places to shuttle metal thereto) or which serve two distinct deposition modules (e.g., each intermediate stage serves a single deposition module).

In one embodiment, two intermediate stages/intermediate stages that serve the same deposition module may contain different metals. Alternatively, in one embodiment, a single intermediate stage/intermediate stage can be configured to contain more than one metal, where the metals are different.

For example, the metals may differ in their type, chemical composition, metallurgical properties, mechanical properties, or other properties. The building plan may specify the locations at which specific metals with desired properties may be deposited. Thus, embodiments of the disclosure enable the manufacturing of cast with locally controlled metal properties.

Figure 2 shows a metal system arrangement 200, which exemplifies several options for implementing embodiments constructed and operative in accordance with the invention. The metal system arrangement 200 includes stationary input metal-dose reservoirs 202a and 202b in Tier 1, intermediate stages 204a - 204h in Tier 2, and deposition modules 206a - 206j (Tiers 2 and 3 are each represented by two respective rectangles only for the sake of convenience of demonstration). Some intermediate stages are served (or fed) by a single stationary input metal reservoir, and some by two stationary input metal reservoirs. Some intermediate stages serve (or feed) a single deposition module, and some serve more than one deposition module. Some deposition modules are served by a single intermediate stage and some are served by more than one intermediate stage. As exemplified, deposition module 206a is served by intermediate stage 204a which also serves deposition module 206b, which is also served by intermediate stage 204b, which also serves deposition module 206c, while both intermediate stages are fed from stationary metal-dose reservoir 202a. Intermediate stage 204c is served by stationary input metal-dose reservoirs 202a and 202b, and serves deposition modules 206d and 206e. Accordingly, intermediate stages 204a, 204b and 204c can be swapped in turns to receive service from stationary metal-dose reservoir 202a, and intermediate stages 204a and 204b can be swapped in turns to serve deposition module 206b. Intermediate stage 204d is fed by stationary metal-dose reservoir 202b and feeds deposition modules 206f and 206g. Intermediate stages 204e and 204f are fed by stationary metal-dose reservoir 202a and feed a single deposition module 206h, such as by cyclic swap of places for shuttling metal doses in turns between stationary metal-dose reservoir 202a and deposition module 206h. Intermediate stages 204g is fed by stationary metal-dose reservoirs 202a and 202b and feed a single deposition module 206i. Intermediate stage 204h is fed by stationary metal-dose reservoir 202b and feed a single deposition module 206j which is encased together with intermediate stage 204h in a single encasing 208.

The stationary input metal reservoir can contain large amounts of metal - at the order of tens and hundreds of kilograms, up to 1, 2 tons and more. Moving thereof is required for metal replenishment - no moving thereof is required during production. The intermediate stage is lightweight in comparison to the stationary input metal reservoir, by containing a smaller amount of metal dose, thereby allowing fast and accurate maneuvering of a smaller dose, if required. The deposition module contains the smallest amount (a deposition-session dose) primarily for allowing fast and accurate maneuvering of the deposition means, and thereby also saving heating energy resources required for bringing the molten metal into a casting-ready temperature (e.g., 1150- 1450-C for Iron, often 13005C). For example, input metal in the amount of 200kg., 500Kg., 1 ton, 2 tons of metal may be handled by the first tier; the second tier - the metal-carrying movable tier, carries a smaller amount of metal between the first tier and the deposition module. For example, 5kg, 7Kg., 10Kg., 20Kg.2, 30Kg., 40Kg. of metal may be handled by the third tier; and the third tier - the deposition module - handles the smallest amount of metal, for example in a volume facilitating controllable heating and deposition and accurate positioning. For example, very small amounts of 50gr., lOOgr., 200 gr., 500 gr., and up to lkg., 2Kg., 5kg, 7Kg., lOKg. of metal may be handled by the third tier. The third tier may deposit metal at the pace or rate of up to lOcc/sec (or slower).

In some instances, wherein the intermediate stage is sufficiently small for fast maneuvering as required for deposition, the deposition module and the intermediate stage are physically coupled and movable together - thereby coupling tier 2 and tier 3 in a single movable unit. In other words, tiers 2 and 3 may be integrated.

Figure 3A is a block diagram of a casting system 3000 that incorporates a metal deposition system 3002 according to embodiments of the invention. Metal deposition system controller 3004 is incorporated with, hosted by, or in data communication with casting system controller 3006.

Casting system 3000 further comprises mold construction system 3008 operable in synchronization with operational cycles of the metal deposition system 3002 (via communication of mold construction system controller 3010 with the metal deposition system controller 3004) to additively create a vertical stack of production layers PL, each including metal in an object region 3016 surrounded by a mold region 3014. It should be understood that the object design defines the number of object regions surrounded by the respective mold regions, the number of production layers PL and additional parameters.

In each production layer, a respective mold construction system constructs the mold region 3014 - for example, by depositing mold paste (in situ mold construction) or by placing a remotely fabricated mold region (ex-situ mold construction). In some embodiments, the mold region of a production layer undergoes a surface treatment before the fabrication of the respective object region starts. Once the mold region 3014, e.g. a mold layer, of a current production region is ready, the metal deposition system, e.g., according to embodiments of the present disclosure, fabricates the object region 3016 by depositing molten metal into the respective mold region 3014. In some or most production instances, the currently-deposited molten metal is deposited on previously- deposited metal. The previously-deposited metal may be heated up to melting and optionally above ("surface heating" or "area heating") before metal deposition ("predeposition heating", during deposition and after metal deposition ("post deposition heating"). The molten metal to be deposited is heated ("melting heating"), and once deposited - the currently-deposited molten metal experience post deposition heating, if applied. Once the vertical stack of production layers is complete and removed from the casting system, the structure composed of mold regions may be removed.

In some embodiments of the in-situ process, the mold region(s) of each production layer is/are constructed within the common production environment (e.g., a production chamber encompassing build table 3012 or parts thereof) with the object region(s) of the same production layer, and the mold material being deposited is in a green-body state. For example, the in-situ process may utilize the deposition of ceramicbased green-state paste. In another example, the in-situ process may utilize a binder jetting operation, i.e., using a mold powder provision device, a mold binder dispensing device and a mold powder removal device. In the ex-situ process, the mold construction unit forming the mold region is constructed in a separate production environment and is brought to the build table 3012 adjacent to that of the object region by a separate holding / translating unit (e.g., robot). For example, the ex-situ process may utilize a binder jetting operation, i.e., using a mold powder provision device, a mold binder dispensing device and a mold powder removal device. In another example, the ex-situ process may utilize a stack of frames, each containing a sand-based mold region with or without a replaceable pattern.

During operation, in a current production layer PL, metal deposition starts after mold construction system 3008 completes the construction of mold region 3014 of the current production layer PL. Metal system 3002 deposits molten metal on the object region defined by mold region 3014 and the previous production layer. Metal system 3002 deposits molten metal on selected deposition locations DL while traveling over build table 3012 along a deposition path DP. Before metal deposition, during metal deposition and/or after metal deposition, metal deposition system 3002 may further heat a working area WA near or around the deposition location DL. Casting system 3000 is configured to carry out metal deposition methods implementing the three-tier architecture and metal deposition systems, according to embodiments of the present disclosure.

Figure 3B conceptually illustrates a production floor plan of a contained casting system 300 for additive metal casting accommodating a metal deposition system according to various embodiments of the present invention, employing the 3-tier concept illustrated in Figs. 1 and 2.

To implement the above-outlined production scenario discussed with reference to Figure 3A, System 300 includes a first build table 301 and a second build table 302, accessible by the mold construction system and metal deposition system. System 300 may be employed for the production of several metallic objects concurrently. System 300 may be employed for the production of large and very large metallic objects, for example, having a width (or length) in the range of 40cm to 200cm. Build tables 301, 302 are capable of operating both in parallel simultaneously, as well as sequentially to optimize performance factors such as throughput, capacity, energy consumption, material utilization, and so on. In some embodiments, each of build tables 301, 302 may have a length or width in the range of 40cm to 200cm. In some embodiments, the footprint of system 300 in framed enclosure 340 is approximately 17 meters x approximately 8.5 meters with a clearance height of approximately 5 meters, for a floor area of approximately 145 square meters and a volume of approximately 720 cubic meters.

A first loading/unloading dock 331 and a second loading/unloading dock 332 provide controlled access for introducing and extracting material and finished product.

System 300 includes a containment enclosure 340 which provides an environmental barrier to confine gases, e.g. a protective environment as disclosed herein,, liquids and vapors, and high temperatures in a controlled space. External support facilities include items such as an electrical cabinet 311, a chiller 313, a ceramic feed tank 312, and a lift loader/unloader 333. Certain items (such as feed tank 312 and chiller 313) can be located on the roof of containment enclosure 340 to reduce the system footprint. Enclosure 340 is connected to external facility support infrastructures (not shown), including environmental evacuation systems, power mains, water and gas supply, and so forth.

In some embodiments, a build table within enclosure 340 is further enclosed in an oven for keeping a casting-in-progress at an elevated temperature (but below the pre-heating and post-heating temperatures).

Two production assemblies - a metal production assembly 322 and a mold construction assembly 326 are shown. Metal production assembly 322 may, for example, form part of the metal deposition system according to embodiments of the present disclosure. Metal production assembly 322 is mounted on a linear bed 323 with tracks 324, and mold construction assembly 326 is mounted on a linear bed 327 with tracks 328, giving them access to both build table 301 and build table 302.

Metal production assembly 322 incorporates a deposition module 352 (tier 3) according to embodiments of the present disclosure. As an example, metal production assembly 322 is shown combined with an integrated heating assembly 350, which provides surface heating and melting heating. Tier 2 is shown in Figure 3 as a solid metal loader/unloader station 354. Tier 1 is shown in Figure 3 as a solid metal stock 356 (e.g., rod, bar or wire crate). Solid metal stock 356 may be replaced by lift loader/unloader 333 or by another lifting means (not shown).

System 300 may operate in an atmospheric environment, or in a protected environment. According to certain embodiments, the production area or part thereof are maintained as an inert environment during at least some of the production operations.

Also shown in Figure 3B is a single mold surface treatment assembly 329 for carrying out specialized mold-finishing operations, including, but not limited to, mechanical operations such as milling, grinding, and polishing, and/or operations associated with mold curing.

Aspects of the present disclosure will be further discussed with reference to the additive casting system of Figures 3A-3B. In should be noted that the aspects of the present disclosure can be implemented by other molten-metal additive manufacturing systems that use solid metal or molten metal as input.

Solid input metal is not limited to rods. Bars, billets, and any other metal piece can be used. Solid metal input may be used with melting at either tier 1, tier 2 or tier 3. The use of metal rods, bars, billets or any other metal input type with predetermined weight, size, shape and metal properties (microstructure and other metallurgical properties, mechanical properties, and chemical properties) is advantageous for melting at any tier.

Melting at tier 3 provides the advantage of delaying the melting to later production stages, compared to melting in tiers 1 and 2. Delayed melting may reduce melt aging (changes in the chemical composition of the melt under continuous heating). Safety requirements involved with limited travel of molten metal compared to the travel of large amounts of molten metal, may be eased.

Figures 4, 5A-5B show specific but non-limiting embodiments of metal deposition systems employing metal rods as input and melting at tier 3. Figure 6 illustrates a rod manipulator that can be used with the systems illustrated in Figures 4 and 5A-5B.

Figure 4 shows a metal deposition system 400 comprising a stationary input metal reservoir 401 and a single intermediate stage 402 (e.g. a rod fetcher) in proximity to stationary input metal reservoir 401 for rod replenishment. Rod load manipulator 424 is installed in intermediate stage 402. The metal deposition system 400 further comprises a deposition module 403. The melting module 426is installed in deposition module 403, which is configured for receiving metal rod 423 from rod fetcher, for melting rod 423 into a crucible 404 and for depositing molten metal in the deposition locations (not shown). In some embodiments, the deposition module deposits the molten metal directly into a deposition location (not shown).

Stationary input metal reservoir 401 is configured to allocate solid state metal doses to intermediate stage 402, by solid-metal dose allocator 425. A magazine of, e.g., 4 metal rods 422 allocated to intermediate stage 402 is shown as a non-limiting example. In operation, intermediate stage 402 travels on the build plane from the location of stationary input metal reservoir 401 toward deposition module 403. Upon engaging with deposition module 403, intermediate stage 402 by rod load manipulator 424 allocates one or more rods 422 to deposition module 403. For example, one of rods 422 is attached to a rod holder installed on deposition module 403 (not shown). Rod load manipulator 424 may be configured to unload the remaining of a previously allocated rod, if any. The newly attached rod 423 can be melted by rod melting ring coil 426 upon activation to drip down to a deposition location or, as shown in FIG. 4 to an optional crucible 404, from which molten metal 410 drips through outlet 406 to the deposition location (not shown). During the melting of rod 423 and molten metal deposition, intermediate stage 402 may travel to a nearby location and be ready to allocate the second of the of 4 metal rods 422, and then the third rod and fourth rod to the deposition module 403 when needed. Upon allocating all of the 4 metal rods 422, the intermediate stage 402 may return to stationary input metal reservoir 401 for rod magazine refill.

In the example of Figure 4, the deposition module 402 comprises a buffer crucible 404 (also referred to as application deposition crucible). The buffer crucible may be used for several functions, including, but not limited to, metallurgical processing of the molten metal, such as ensuring the same melting time and same heating profile for all of the input rods; proper addition of additives and inoculants (addition of additives and inoculants may be implemented in any of the other crucibles); dynamically enlarge or reduce the volume of molten metal ready for deposition, deposition rate control, or the like.

Buffer crucible 404 receives molten metal dripping from rod 423 in response to melting heating by melting heater/s 426. Buffer crucible 404 may be a plunger-based crucible, as illustrated in Figure 7, but this is not necessarily so. Buffer crucible 404 may contain molten metal 410, outlet 406, plunger 408, heating element 418, valve heating element 419, and pressure adjusting means 420. A controller of the metal deposition system (not shown) controls the lifting of plunger 408 to block and unblock outlet 406 as an on-off valve, heating element 418 for retaining metal 410 in a molten state, valve heating element 419 for further heating of metal 410 either for facilitating drip through outlet 406 or for a casting ready temperature for additive casting. The controller (not shown) may further control additional operating parameters of the deposition module 403, such as rod holder for setting rod height, and rod melting heater/s 426 to control melting rod power.

In the specific examples illustrated in Figure 4 as well as in the other examples illustrated herein for various implementations of the principles of the present disclosure, controllable deposition of molten metal for additive metal casting is facilitated. In each of the architectural tiers, the volume allocated, the melting process, target temperatures and deposition rate can be controlled, to ensure repeatability and successful industrial scaling.

Figure 5A schematically illustrates another embodiment of the present disclosure, at which no application deposition crucible is used. Metal deposition system 500 comprises a stationary input metal reservoir configured to receive and allocate solid metal. Solid metal in the form of metal rods R is shown.

The intermediate stage 502 (tier 2) may comprise at least an arm with an actuator (not shown) which conveys a metal rod R from the stationary reservoir to the deposition module 503. The deposition module 503 is shown with a metal rod 523 in place. Optionally, the same arm of intermediate stage 502, or another arm, may unload a leftover (tail) of a previously allocated metal rod from the deposition module. In one embodiment, the intermediate stage may be configured to travel to the deposition module, orthe deposition module may be configured to travel to the intermediate stage, when the metal rod is conveyed.

Thus, in the embodiment shown in Figure 5A, the deposition module 503 is configured for realizing molten metal deposition positioning, melting heating and deposition heating and deposition flow rate control into a single unit. The melting module and the deposition module can, thus, be integrated.

Rod holder 526 may carry rod 523. The metal rod 523 may have a weight in the range of 5Kg. to lOKg. The deposition module 503 may travel rod 523 over the build plane and accurately position rod 523 above the deposition locations. Deposition module 503 may further comprise melting heater/s 504 for melting the tip of rod 523 to thereby release metal drops 528 (or drops forming a stream of metal) onto the working areas (deposition locations) 550 along a vertical decent path. The deposition module 503 may further comprise an optional shaft heater/s 530 for providing additional heating to metal drops 528 during their passage from the tip of rod 523 to the working areas 550. Heater/s 504, 530 may employ controllable induction heating.

Rod 523, melting heater/s 504, optional shaft heater/s 530 and optionally rod magazine and rod load manipulator may be physically coupled to a common frame and travel module 524. Relative displacement between elements of the deposition module 503 may be provided. For example, to ensure a fixed position, particularly a fixed vertical position, of the tip of rod 523 over working area 550 (deposition locations), the height of rod 523 may be controllably adjusted by rod holder 526.

Deposition module 503 may travel over the build plane (the current production layer comprising object region 540 and mold region 542), e.g., in the X-Y plane, toward the stationary input metal reservoir for rod refill, and to the deposition locations (working areas) 550 along a deposition path (not shown).

In operation, the melting heater/s 504 heats a portion of rod 523, including the shoulder and tip of rod 523 and molten metal 528 drips downward in discrete drops, continuous dripping or a stream. The optional shaft heater/s may provide additional heating to molten metal528, if desired. Melting heater/s 504 and optional shaft heater/s 530 may be separately controlled. The position, volume, shape and temperature of molten metal 528 under the influence of heaters 504 and optional shaft heaters 530 may be sensed. The readings of the sensed parameters may be used by the system controller (not shown) to control the melting heater/s 504 and optional shaft heater/s 530 separately. The deposition flow rate of deposition module 503 is a function of the travel speed of rod 523 over the working areas and the proximity of the rod's tip or shoulder to the melting heater/s 504 (rod height). The travel speed of rod 523 over the working areas can be measured by measuring the travel speed of the deposition module 503 (common travel frame). Rod height with respect, e.g., to holder 526 or any other known reference, is indicative of the proximity of the rod's tip or shoulder to the melting heater/s 504. These parameters can be sensed. The readings of the sensed parameters may be used by the system controller (not shown) to control the travel speed of rod 523 over the working areas and the rod height.

In some embodiments, molten metal 528 are required to reach the working areas 550 for deposition at a casting-ready temperature which is higher than the melting temperature (over-heating). Dedicated sensors (not shown) may sense, for example, the temperature of molten metal 528 in various positions along their way from the tip/shoulder of rod 523 and the working areas 550 ("shaft" or "decent path"). Readings of the sensed parameters may be used by a system controller (not shown) to control the operation of the optional shaft heater/s 503.

In some embodiments, as shown in Figure 4, molten metal 528 may be accumulated in a deposition buffer crucible (not shown in Figure 5A or 5B). The deposition buffer crucible may be positioned within the zone impacted by deposition heaters 504.

Figure 5B shows a deposition module 503-I. Deposition module 503-I is similar to deposition module 503 of Figure 5A, and features, aspects or details may be combined, except that (1) it is not equipped with shaft heater/s 530 and (2) deposition module 503-1 further comprises area heater/s 560 for working area heating: the deposition module is positioned in proximity to working areas 550 - the areas on which the molten metal is to be deposited. Working area heaters 560 may provide heating to the deposition locations (working areas) 550 - for example, pre-deposition heater/s, area deposition heater/s and/or post-deposition heater/s may be placed in proximity to the working areas 550, for providing pre-deposition heating during-deposition heating and/or post-deposition heating of the working areas. In some embodiments, the working area heater/s may be physically and/or operably coupled to the deposition module. For example, the area heater/s may be carried by the travel unit that moves the deposition module over the build plane. With reference to Figure 5A, area heaters 560 may be carried by frame and shared travel module 524. In another example, the controller that controls the deposition temperature may further control the operation of the working area heater/s such that the control of the molten metal upon deposition will reflect all the heat sources residing in proximity to the working areas and the molten metal drops (or stream) upon deposition.

In accordance with some aspects of the present disclosure, the working area heater/s includes at least one heating element encircling the deposition module overthe build plane (this is shown in Figure 5B). In accordance with some aspects of the invention, the heating elements can be rotated about the deposition module.

In accordance with some aspects of the present disclosure, the following elements shown in Figures 5A-5B are maintained as an inert environment: the tip and shoulder area of rod 523, molten metal 528, working areas 550 under the influence of area heater/s 560 and optionally heater/s 504, shaft heater(s), and area heater/s 560. For example, the environment to be shielded is protected by a protection sleeve that is carried by frame (not shown in Figures 5A-5B).

In accordance with some aspects of the invention, the controller, such as controller 116 (shown in Figure 1) controls one or more parameters selected from the list including: transport speed of the intermediate stage, travel speed of the deposition module, movable-dose transferring rate to the intermediate stage, deposition-session dose transferring rate to the deposition module, melting rate of the melting module deposition, rod height and proximity of rod's tip/shoulder to the melting heater/s, rate of the deposition module, the temperature of the metal in the deposition module, the temperature of the metal in the intermediate stage, deposition progress along a deposition path over the build plane, and distance between adjacent deposition path lines over the build plane.

In accordance with some aspects of the invention, the controller is configured to control the depositing of the molten metal at a controlled rate, by controlling one or more of: the travel speed of the deposition module over the working areas, rod height, melting temperature (current supplied to the melting heater/s 504).

In accordance with some aspects of the invention, the controller is configured to control a start and a stop of deposition during additive metal casting by controlling one or more of: travel speed of the deposition module over the working areas, rod height, melting temperature (current supplied to the melting heater/s 504).

In accordance with some aspects of the invention, the molten-metal deposition system further includes sensors, indicative of at least one parameter selected from the group of: temperature of molten metal incoming to a descent path in the deposition module, temperature of molten metal outgoing from the descent path right before depositing in the build plane, volume or flow rate of molten metal incoming to the descent path (e.g., a drip counter, width of stream detector), volume or flow rate of molten metal outgoing from the descent path (e.g., a drip counter, width of stream detector), and liquid height of molten metal in a crucible or pool, wherein the controller is responsive to readings of the sensors for controlling one or more of the parameters.

Reference is now made to Figure 6 which provides additional information on an exemplary rod manipulator that can be used in system 500 shown in Figures 5A-5B as part of intermediate stage 502. An element of Rod manipulator - arm 602 - is schematically shown in Figure 6. It is to be understood that the construction and operation of the rod manipulator are not delimiting the present disclosure and are not described herein in detail, except to note the following: Rod manipulator is configured and operational for delivering rods from the rod stock 501 and feeding rods into the deposition module 503 of Figure 5A. For example, Rod manipulator of intermediate stage 502 is configured and operational for advancing and lifting a horizontally disposed metal rod R residing at rod stock 501 (view (A)). Rod manipulator of intermediate stage 502 is configured and operational for flipping rod R into a vertical position (View (B)) or any other suitable position. Rod manipulator of intermediate stage 502 is further configured and operational for inserting rod R into its position in deposition module 503 (or 503-1) (View (C)). As metal rod R gradually shortens by virtue of its melting, holder 526, e.g., configured with an advancing and retracting mechanism along a vertical guiding rail (not shown) is operable to keep the tip of the gradually shortening rod R, proximate to heater/s 504. When rod R is consumed, holder 526 retracts to receive a fresh refill of a new rod R. If rod R leaves any remaining R tail (e.g., a rod portion below a predetermined length), the rod remaining R tail is retracted too and removed. For example, the rod remaining R tail may be removed by the arm 602.

In the present disclosure a plurality of embodiments have been described. According to various implementations, an exemplary embodiment may include on or more of the following features or all of the following features. A metal dose allocator 425, e.g. a portion of a stationary input metal reservoir, can be provided near a rod loader manipulator. The rod load manipulator, e.g. an actuator of the intermediate stage, can place a rod on a deposition module. Further, the rod load manipulator can remove remaining portions of a rod from the deposition module. For example, the deposition module may travel along the table to the rod load manipulator. The road load manipulator may be integrated with the metal dose allocator or the stationary or the stationary input metal reservoirs. A deposition module may include a material addition mechanism and a metal piece applicator is configured to unload a previously allocated metal rod from the deposition module. At least a portion of a metal deposition dose is provided in an inert environment at least during metal melting and molten metal deposition. Heaters like surface heater or shaft heaters can be provided.

Figure 7 is a schematic cross-sectional illustration of a crucible 700 constructed and operative in accordance with some embodiments of the invention, featuring a plunger. Crucible 700 can serve as the application depositor crucible discussed with reference to Figure 4.

Crucible 700 includes ladle or crucible vessel 702, housing 704, drainage outlet orifice 706, and plunger 708. Molten metal 710 is contained in vessel 702. Bottom 714 of vessel 702 is slanting or tapering to allow effective drainage of molten metal 710 through outlet orifice 706, as a flow, trickle, or drip 715 of molten metal 710. Plunger 708 features a plunger rod 712 and bulbous head 717, and is configured to selectively block and unblock outlet orifice 706 when plunger 708 is lowered or elevated, respectively, and thereby functions as a 'start-stop' valve, wherein a controller controls the elevation or lowering of plunger 708 by adequate lifting means (e.g., a motorized wheel to the circumference of which the upper end of plunger rod 712 is hinged and thereby lifted or lowered by a slight roll of the wheel about its axis). The gap between housing 704 and vessel 702 leaves space 716 in which heating elements 718 can be placed for rendering and maintaining molten metal 710 in a molten state. Heating element 718 is presented as rounded cross-sections of a resistive or inductive electric wire wound around or about vessel 702, which allows subtle control of accurate temperatures by a controller. However, the use of indirect induction heating may also be achieved by embedding a conductive layer in the crucible wall. Housing 704 provides an isolation covering that retains the heat about vessel 702 and provides support for mounting heating elements 718. Heating elements 718 can be deployed about vessel 702 without housing 704, but would require other supporting means for coupling to vessel 702. In the case of resistive heating, heat would dissipate without the isolating covering of housing 704, and more energy would be required to reach and maintain the required temperature within vessel 702.

Accordingly, crucible 700 can be implemented as any crucible according to some embodiments of the invention by virtue of controlling its movement, its dynamic heating (by heating element 718) and its start-stop mechanism (by lifting and lowering plunger 708).

The flow rate of a melt through the orifice is a function of the height of the melt reservoir in the crucible. By maintaining the height of the melt in the crucible, for example by monitoring the melt level and adjusting it by supplying melt from a higher tier unit or a buffer crucible, the flow rate may be controlled, and more specifically, kept constant. Accordingly, a crucible cascade may be used to control the flow rate of the third tier crucible by controlling the height of molten metal in an upstream crucible.

Sensors 720 - for example, height sensor h (e.g., a camera) and a temperature sensor T (e.g., a thermal camera) are used to measure the molten metal level within crucible 700. Sensors 720 are in data communication with the system controller 722 that controls plunger 708 in alignment with the deposition plan and in response to the readings of sensors 720.

In accordance with aspects of the present disclosure, there are provided metal deposition methods that are implemented by a three-tier metal deposition system as described with reference to Figs. 1 to 7.

In some embodiments, illustrated in Figure 8, the metal deposition method 800 for additive casting, comprises the operations of:

In operation 802: Allocating movable-doses of solid metal contained in a stationary input metal reservoir to an intermediate stage and receiving a movable-dose in the intermediate stage. In operation 804: Conveying, by the intermediate stage, the movable dose of solid metal over one or more build tables. In operation 806: Receiving solid metal from the intermediate stage, melting at least a portion of the solid metal and depositing molten metal at a deposition temperature in selected deposition locations in the one or more build tables. Operation 806 may comprise operation (A) of adding additives and/or inoculants to the molten metal. The additives and/or inoculants may be added to the molten metal before deposition, during deposition and/or after deposition. Operation 806 may comprise operation (B) of containing in a crucible and heating metal lingering therein in a molten state, wherein the crucible is disposed in the deposition module. In operation 810: Controlling, by a controller, at least one or more stationary input metal reservoirs, the intermediate stage and the deposition module for depositing molten metal in selected deposition locations in the one or more build tables.

In some embodiments, illustrated in Figure 9, the metal deposition method 900 for additive casting, comprises the operations of:

In operation 902: Allocating a predetermined number of metal pieces having a predetermined shape, size, and weight contained in a stationary input metal reservoir to an intermediate stage. In operation 904: Conveying, by the intermediate stage, the predetermined number of metal pieces over one or more build tables. In operation 906: Receiving at least one metal piece from the intermediate stage. In operation 908: Melting by a melting module accommodated in a deposition module, a portion of the metal piece. Operation 908 may comprise operation (A) of adding additives and/or inoculants to the molten metal. The additives and/or inoculants may be added to the molten metal before deposition, during deposition and/or after deposition. Operation 908 may comprise operation (B) of containing in a crucible and heating metal lingering therein in a molten state, wherein the crucible is placed in the deposition module. In operation 910: Controlling, by a controller, at least one or more stationary input metal reservoirs, the intermediate stage and the deposition module for depositing molten metal in selected deposition locations in the one or more build tables

Operations 810 and 910 may further comprise operation (I) of controlling, by the controller, one or more parameters selected from the list including: (a) transport speed of the intermediate stage; (b) travel speed of deposition module; (c) melting rate of the melting module; (d) deposition rate of the deposition module; (e) temperature of the metal in the deposition module; (f) temperature of the metal in the intermediate stage; (g) deposition progress along a deposition path over the build plane; (h) distance between adjacent deposition path lines over the build plane; and (i) height between the portion of the deposition-session dose of the solid input metal and the melting module.

Operations 810 and 910 may further comprise operation (II) of controlling one or more of the parameters, by a controller responsive to readings of sensors indicative of at least one parameter selected from the one or more of the parameters consisting of: (a) temperature of molten metal outgoing from the deposition module; (b) temperature of molten metal right before depositing in the build plane; (c) volume or flow rate of molten metal outgoing from the deposition module; (d) speed of the deposition module along the deposition path; and (e) height between the portion of the deposition-session dose of the solid input metal and the melting module.

Operations 810 and 910 may further comprise operation (III) of controlling a metal piece holder accommodated in one of the intermediate stages and the deposition module to maintain a predetermined height between the portion of the metal piece and the melting module.

In case Operation 806 and 908 respectively comprise Operation B, Operations 810 and 910 may further comprise Operation (IV) of controlling a metal piece holder accommodated in one of the intermediate stages and the deposition module to maintain a predetermined height between the portion of the metal piece and the melting module.

It will be appreciated by persons skilled in the art that the technique is not limited to what has been particularly shown and described hereinabove.

Several examples and embodiments of the present disclosure were disclosed herein and illustrated schematically. Components such as power supply, protective environment and shielding, motion elements, sensors, control lines and additional components are not shown for simplicity of explanation.

It is noted that throughout the entire description herein, terms such as 'deposit', 'depositing', 'drip', 'dripping', 'drop' and the like, include any drizzle, trickle, flow, stream, release down, and the like, whether continuous or discrete, of molten metal which is deposited, released down or dropped to a lower location, whether a lower vessel or a lower casting location, are interchangeably used herein, irrespective of the discrete or continuous characteristic nature of the flow. In this context, the terms 'pace', 'rate' of such flow are similarly interchangeable and are applicable to evaluating the flux measure of any flow, drip, and the like, discrete or continuous.

In the description and claims of the present application, each of the verbs, "comprise," "include" and "have," and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb.

As used throughout the specification, the terms "metal" or "metallic" refer to any metals and/or metallic alloys which are suitable for melting and casting, for example, ferrous alloys, aluminum alloys, copper alloys, nickel alloys, magnesium alloys, and the like.

Any reference in the specification to a method should be applied mutatis mutandis to a system capable of executing the method and should be applied mutatis mutandis to a non-transitory computer-readable medium that stores instructions that, once executed by a computer, result in the execution of the method. Any reference in the specification to a system should be applied mutatis mutandis to a method that may be executed by the system and should be applied mutatis mutandis to a non-transitory computer-readable medium that stores instructions that may be executed by the system.

The terms "front," "back," "top," "bottom," "over," "under", and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the present disclosure described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of other elements or operations and stages than those listed in a claim. Furthermore, the terms "a" or "an," as used herein, are defined as one or more than one. Also, the use of introductory phrases such as "at least one" and "one or more" in the claims should not be construed to imply that the introduction of another claim element by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim element to inventions containing only one such element, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an." The same holds true for the use of definite articles. Unless stated otherwise, terms such as "first" and "second" are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot be used to advantage.

Description of embodiments of the invention in the present application are provided byway of example and are not intended to limit the scope of the invention. The described embodiments include different features, not all of which are required in all embodiments of the invention. Some embodiments utilize only some of the features or possible combinations of the features. Variations of embodiments of the invention that are described, and embodiments of the invention, including different combinations of features noted in the described embodiments, will occur to persons of the art. The scope of the invention is limited only by the claims.

Claims

1. A metal deposition system for molten-metal additive casting on one or more build tables, comprising

(a) one or more stationary input metal reservoirs configured to contain solid input metal and allocate movable-doses of the solid input metal;

(b) one or more intermediate stages having at least an actuator configured to convey a movable dose of the solid input metal allocated from at least one of the one or more stationary input metal reservoirs;

(c) one or more deposition modules configured to receive a depositionsession dose of the solid input metal from the intermediate stage, and to deposit molten metal; and

(d) one or more travel modules for traveling over the one or more build tables at least one of: the one or more deposition modules and the one or more intermediate stages, wherein the one or more deposition modules are configured to perform heating of at least a portion of the deposition-session dose of the solid input metal to a deposition temperature.

2. The metal deposition system according to claim 1, further comprising a controller for controlling the one or more intermediate stages, the one or more deposition modules, the one or more travel modules and, optionally, the one or more stationary input metal reservoirs, for preparing input metal for deposition, and wherein preparing the input metal for deposition comprises at least one of: positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate.

3. The metal deposition system of any one of claims 1 to 2, wherein the controller is configured to control the one or more travel modules to travel the one or more deposition modules along a deposition path.

4. The metal deposition system of claim 3 wherein the controller is further configured to control a position of at least the portion of the deposition-session dose of the solid input metal above the deposition path.

5. The metal deposition system according to any one of claims I to 4, wherein the one or more intermediate stages further comprise one or more movable metal-dose reservoirs.

6. The metal deposition system according to any one of claims 2 to 5 wherein the one or more deposition modules comprise a material addition mechanism configured to add additives and/or inoculants to the molten metal for adjusting metal properties, and the controller is configured to control an inoculation mechanism.

7. The metal deposition system of claim 6 wherein the controller is configured to control the inoculation mechanism to add the additives and/or inoculants to the molten metal at least at one of (1) before molten metal deposition, (2) during molten metal deposition and (3) after molten metal deposition.

8. The metal deposition system according to any one of claims I to 7, wherein the solid input metal is metal pieces having predetermined shape, size, and weight, and the one or more stationary input metal reservoirs are configured to allocate a predetermined number of metal pieces; the one or more intermediate stages are configured to receive and convey a predetermined number of the metal pieces allocated from the stationary input metal reservoirs; the one or more deposition modules are configured to receive at least one metal piece from the one or more intermediate stages and to deposit molten metal in selected deposition locations in the one or more build tables; and wherein the one or more deposition modules comprises a melting module for melting a portion of the metal piece.

9. The metal deposition system according to claim 8, wherein the at least one metal piece are two or more metal pieces and the two or more metal pieces are metal rods.

10. The metal deposition system according to claim 8 or 9, wherein the metal pieces comprise at least two metal pieces having differing properties.

11. The metal deposition system according to claim 10, wherein the controller controls which metal piece is received by the deposition module.

12. The metal deposition system according to claim 11, wherein the controller is configured to control which metal piece is received by the deposition module as a function of the deposition path.

13. The metal deposition system according to any one of claims 2 to 12, wherein the controller is configured to control the one or more travel modules to travel at least one of the intermediate stage and the deposition module for deposition dose replenishment and to travel the deposition module along a deposition path.

14. The metal deposition system according to any one of claims 1 to 13, wherein the deposition module is physically coupled to the one or more intermediate stages, and movable therewith.

15. The metal deposition system according to any one of claims 8 to 14, wherein at least one of the deposition module and the intermediate stage comprise a metal piece magazine configured to contain the predetermined number of metal pieces.

16. The metal deposition system according to any one of claims 2 to 15, wherein the controller is configured to control the one or more travel modules to travel the deposition module to and from the intermediate stage, and to travel the deposition module along a deposition path.

17. The metal deposition system according to any one of claims 8 to 16, wherein at least one of the intermediate stage and the deposition module comprises a metal piece applicator configured to replace a partially-melted metal piece with a new metal piece.

18. The metal deposition system according to claim 17, wherein the metal piece applicator is configured to unload a previously allocated metal rod from the deposition module.

19. The metal deposition system according to any one of claims 17 to 18, wherein the new metal piece has different properties than the partially-melted metal piece, and the controller controls the replacement as a function of the deposition path.

20. The metal deposition system according to any one of claims 8 to 19, wherein at least one of the deposition module and the intermediate stage comprise a movable metal piece holder for holding a metal piece and the controller is further configured to control the movable metal piece holder to maintain a predetermined height between the portion of the metal piece and the melting module.

21. The metal deposition system of any one of claims 1 to 20, wherein the deposition module further comprises one or more shaft heaters configured to heat the molten metal after melting and before arrival to a selected deposition location.

22. The metal deposition system of any one of claims 1 to 21, wherein the deposition module further comprises one or more area heaters configured to heat a working area in the selected deposition locations.

23. The metal deposition system of claim 22, wherein the controller is further configured to control the area heaters to heat the working area at least one of: before metal deposition, during metal deposition and after metal deposition.

24. The metal deposition system of any one of claims 5 to 23, wherein the controller controls one or more parameters selected from a list including:

(a) transport speed of the movable metal-dose reservoir of the one or more intermediate stages;

(b) travel speed of deposition module;

(c) movable-dose transferring rate to the movable metal-dose reservoir;

(d) melting rate of the melting module;

(e) deposition rate of the deposition module;

(f) temperature of the metal in the deposition module;

(g) temperature of the metal in the movable metal-dose reservoir;

(h) deposition progress along a deposition path over a build plane;

(i) distance between adjacent deposition path lines over the build plane; and

(j) height between the portion of the deposition-session dose of the solid input metal and the melting module.

25. The metal deposition system of claim 24, further comprising sensors indicative of at least one parameter selected from the group consisting of:

(a) temperature of metal incoming to the deposition module;

(b) temperature of molten metal outgoing from the deposition module right before depositing in the build plane;

(c) volume or flow rate of molten metal incoming to a descent path;

(d) volume or flow rate of molten metal outgoing from the descent path;

(e) liquid height of molten metal in a crucible or pool; and

(f) height between the portion of the deposition-session dose of the solid input metal and the melting module, wherein the controller is responsive to readings of the sensors for controlling one or more of the parameters.

26. A metal deposition system according to any one of claims 1 to 25, further comprising an application depositor which is configured to receive molten metal from the deposition module, heat the molten metal to an additive-casting-temperature, and drip, drop, drizzle, trickle, flow, or stream molten metal to a selected location for depositing.

27. A metal deposition system according to any one of claims 2 to 26, further comprising a deposition dose protection unit, and the controller is further configured to control the deposition dose protection unit maintaining at least a portion of a metal deposition dose in an inert environment at least during metal melting and molten metal deposition.

28. A casting system for casting a metallic object by constructing a plurality of production layers forming a vertical stack, wherein production layers of the plurality have mold regions, wherein production layers of the plurality have object regions defined by the mold regions, and wherein a current production layer is constructed upon a top surface of a previous production layer of the vertical stack, the casting system comprising: a mold construction system operative to construct a mold region of the current production layer; a metal deposition system operative to construct an object region of the current production layer; a build table, for supporting the vertical stack of production layers; and a controller for controlling at least the mold construction system and the metal deposition system, wherein the metal deposition system is the metal deposition system according to any of claims 1 to 27.

29. A metal deposition method for additive casting, comprising the operations of:

(a) allocating movable-doses of solid metal contained in a stationary input metal reservoir to an intermediate stage having at least an actuator and receiving a movable-dose in the intermediate stage;

(b) conveying, by the intermediate stage, the movable dose of solid metal over one or more build tables;

(c) receiving solid metal from the intermediate stage and depositing molten metal;

(d) depositing, by a deposition module, the metal in a form of molten metal at a deposition temperature in selected deposition locations in the one or more build tables; and

(f) controlling, by a controller, at least the one or more stationary input metal reservoirs, the intermediate stage, and one or more travel modules for preparing input metal for deposition, wherein preparing the solid metal for deposition comprises at least one of: positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate; and wherein the deposition module is configured to perform at least one of the positioning, heating to a deposition temperature, adjusting material properties, and setting a deposition rate.

30. A metal deposition method according to claim 29, wherein the movable-doses of solid metal are a predetermined number of metal pieces having predetermined shape, size, and weight contained in a stationary input metal reservoir; the intermediate stage is a movable metal-piece reservoir; the deposition module receives at least one metal piece from the movable metal-piece reservoir; the method further comprises melting, by a melting module accommodated in deposition module a portion of the metal piece; and controlling, by a controller, at least the one or more stationary input metal reservoirs, the movable metal-piece reservoir and the deposition module for depositing molten metal in selected deposition locations in the one or more build tables.

31. The metal deposition method according to claim 29 or 30, further comprising controlling a metal piece holder accommodated in one of the intermediate stage and the deposition module to maintain a predetermined height between the portion of the metal piece and the melting module.

32. The metal deposition method according to any one of claims 29 to 31, further comprising controlling, by the controller, one or more parameters selected from a list including:

(a) transport speed of the movable metal-piece reservoir of the intermediate stage;

(b) travel speed of deposition module;

(c) melting rate of the melting module;

(d) deposition rate of the deposition module;

(e) temperature of the metal in the deposition module;

(f) temperature of the metal in the movable metal-piece reservoir;

(g) temperature of metal incoming to the deposition module;

(h) deposition progress along a deposition path over a build plane;

(i) distance between adjacent deposition path lines over the build plane; and

(j) height between the portion of a deposition-session dose of a solid input metal and the melting module.

33. The metal deposition method of claim 32, further comprising controlling one or more of the parameters, by a controller responsive to readings of sensors indicative of at least one parameter selected from the one or more of the parameters consisting of:

(a) temperature of metal incoming to the deposition module

(b) temperature of molten metal outgoing from the deposition module;

(c) temperature of molten metal right before depositing in the build plane;

(d) volume or flow rate of molten metal outgoing from the deposition module;

(e) speed of the deposition module along the deposition path; and

(f) height between the portion of the deposition-session dose of the solid input metal and the melting module.

34. The metal deposition method according to any of claims 29 to 33, further comprising containing in a crucible and heating metal lingering therein in a molten state, wherein the crucible is disposed in the deposition module.

35. The metal deposition method according to claim 34 wherein the controller is further configured to control a temperature of molten metal in the crucible and/or a height of the molten metal in the crucible.

36. The metal deposition method according to claim 35 wherein the controller is further configured to control a flow of molten metal lingering out of the crucible.

37. The metal deposition method according to any of claims 29 to 33, further comprising adding additives and/or inoculants to the molten metal.