CA3107000A1

CA3107000A1 - Wire force sensor for wire feed deposition processes

Info

Publication number: CA3107000A1
Application number: CA3107000A
Authority: CA
Inventors: Elad Taig; Mateo Pena Doll; Duncan MCCALLUM
Original assignee: Digital Alloys Inc
Current assignee: Digital Alloys Inc
Priority date: 2018-08-07
Filing date: 2019-08-05
Publication date: 2020-02-13
Also published as: WO2020033337A1; JP2021531981A; EP3833534A1

Abstract

A method of printing at least a portion of a three-dimensional (3D) object of the present disclosure may comprise directing a first portion of at least one wire toward and in contact with the support or a deposited portion of the 3D object, in accordance with at least one parameter. Next, one or more sensors may be used to generate a signal indicative of a reaction force exerted by the support, or the deposited portion of the 3D object, against the at least one wire, to provide a measured value. The at least one parameter may be adjusted in response to the measured value to provide at least one adjusted parameter. A second portion of the at least one wire may be brought toward and in contact with the support, or the deposited portion of the 3D object, in accordance with the at least one adjusted parameter.

Description

WIRE FORCE SENSOR FOR WIRE FEED DEPOSITION PROCESSES
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No.
62/715,373, filed August 7, 2018, which is entirely incorporated herein by reference.
BACKGROUND

[0002] Wire feeding techniques are widely used in a number of different applications including wire welding and additive manufacturing. A wire feeder may comprise a roller that is in frictional contact with a wire to advance the wire towards a wire receiver.

[0003] In a welding apparatus (e.g., an apparatus for gas metal arc welding or flux-cored arc welding), a wire feeder may be used to feed a wire from a wire source (e.g. a metal wire spool) to a nozzle of a welding gun. The welding gun may create heat to melt a portion of the wire and a work piece to form a pool of molten metal. The pool of molten metal may cool and solidify on the work piece. The pool of molten metal may join a plurality of work pieces.

[0004] Additive manufacturing techniques such as three-dimensional (3D) printing may also use wire feeding techniques. In an example, a polymeric material may be pulled by a wire feeder from a source into a nozzle, then melted, and subsequently deposited into a specified pattern in a layer-by-layer fashion to form a 3D object.
SUMMARY

[0005] The present disclosure provides systems and methods of feedstock feeding that may help avoid various disadvantages of other feedstock feeding methods and systems. Systems and methods of the present disclosure enable a feedstock to be directed from a source of the feedstock (e.g., a wire spool) to a feedstock receiver in a manner that reduces stress(es) while sensing forces imposed on the feedstock. This may advantageously increase the longevity of various components of systems of the present disclosure.

[0006] In an aspect, the present disclosure provides a method for printing at least a portion of a three-dimensional (3D) object adjacent to a support, or a deposited portion of the 3D object, comprising: (a) directing a first portion of at least one wire toward and in contact with the support, or the deposited portion of the 3D object, in accordance with at least one parameter; (b) upon contacting the at least one wire with the support, or the deposited portion of the 3D object, using one or more sensors to generate a signal(s) indicative of a reaction force exerted by the support, or the deposited portion of the 3D object, against the at least one wire, to provide a measured value; (c) adjusting the at least one parameter in response to the measured value to

7 PCT/US2019/045177 provide at least one adjusted parameter; and (d) bringing a second portion of the at least one wire toward and in contact with the support, or the deposited portion of the 3D
object, in accordance with the at least one adjusted parameter.
[0007] In some embodiments, the at least one parameter is adjusted when the reaction force exceeds a threshold value. In some embodiments, the method for printing at least a portion of a 3D object further comprises subjecting the second portion of the at least one wire to heating upon flow of electrical current through the at least one wire and into the support, or the deposited portion of the 3D object, or vice versa, which heating is sufficient to melt the second portion of the at least one wire. In some embodiments, the method for printing at least a portion of a 3D
object further comprises depositing the second portion of the at least one wire on the support, or the deposited portion of the 3D object, thereby forming the at least the portion of the 3D object.

[0008] In some embodiments, the first portion of the at least one wire is directed through a wire feeding assembly. In some embodiments, the at least one parameter is selected from the group consisting of a wire feed speed, distance between a tip of the at least one wire and the support or the deposited portion of the 3D object, distance between the tip of the at least one wire and the at least the portion of the 3D object, amount of power applied to the wire feeding assembly, amount of current applied to the wire feeding assembly, and amount of voltage applied to the wire feeding assembly. In some embodiments, the one or more sensors are kinematically mounted to hold the wire feeding assembly. In some embodiments, the wire feeding assembly comprises a supporting wire guide and a wire feeder, wherein the supporting wire guide accepts the at least one wire from the wire feeder and directs the at least one wire towards the support, or the deposited portion of the 3D object. In some embodiments, the supporting wire guide is in contact with the wire feeder. In some embodiments, the one or more sensors comprise one or more strain gauges.

[0009] In some embodiments, prior to (a), the one or more sensors is calibrated. In some embodiments, (b) comprises measuring the reaction force in isolation from an upstream tension of the at least one wire. In some embodiments, the first portion of the at least one wire is directed using a print head, and wherein (b) comprises (i) determining an applied force applied by a gantry to the print head, and (ii) removing a weight of one or more printing components from the applied force to determine the reaction force. In some embodiments, the one or more printing components is selected from the group consisting of sensor, frame system, mount plate, drive motor, driver roller, preload motor, and preload roller. In some embodiments, the method for printing at least a portion of a 3D object further comprises, prior to (a), selecting the at least one parameter. In some embodiments, the support is a platform. In some embodiments, the support is a previously deposited portion of the 3D object. In some embodiments, the support is a sacrificial obj ect.

[0010] In another aspect, the present disclosure provides a system for printing at least a portion of a three-dimensional (3D) object adjacent to a support or a deposited portion of the 3D
object, comprising: a support configured to hold the at least the portion of the 3D object; a source configured to hold at least one wire, which at least one wire is usable for the printing of the at least the portion of the 3D object; one or more sensors configured to generate a signal(s) indicative of a reaction force of the support, or the deposited portion of the 3D object, against the at least one wire; a power supply configured to flow electrical current through the at least one wire and the support, or the deposited portion of the 3D object; and a controller operatively coupled to the power supply, wherein the controller is configured to: i.
direct a first portion of the at least one wire toward and in contact with the support, or the deposited portion of the 3D
object, in accordance with at least one parameter; ii. upon contacting the at least one wire with the support, or the deposited portion of the 3D object, receive the signal(s) from the one or more sensors indicative of the reaction force exerted by the support, or the deposited portion of the 3D
object, against the first portion of the at least one wire to provide a measured value; iii. adjust the at least one parameter in response to the measured value to provide at least one adjusted parameter; and iv. direct a second portion of the at least one wire toward and in contact with the support, or the deposited portion of the 3D object, in accordance with the at least one adjusted parameter.

[0011] In some embodiments, the system for printing at least a portion of a 3D object further comprises a wire feeding assembly comprising a supporting wire guide and a wire feeder, wherein the supporting wire guide accepts the at least one wire from the wire feeder and directs the at least one wire towards the support, or the deposited portion of the 3D
object. In some embodiments, the one or more sensors are kinematically mounted to hold the wire feeding assembly. In some embodiments, the supporting wire guide is in contact with the wire feeder. In some embodiments, the one or more sensors comprise one or more strain gauges.
In some embodiments, the controller is configured to direct flow of electrical current through the second portion of the at least one wire and into the support or the deposited portion of the 3D object, or vice versa, to subject the second portion of the at least one wire to heating, which heating is sufficient to melt the second portion of the at least one wire. In some embodiments, the controller is configured to direct the second portion of the at least one wire to be deposited on the support or the deposited portion of the 3D object, thereby forming the at least the portion of the 3D object.

[0012] In some embodiments, the controller is configured to measure the reaction force of the at least one wire in isolation of an upstream tension of the at least one wire. In some embodiments, the controller is configured to adjust the at least one parameter when the reaction force exceeds a threshold value. In some embodiments, the support is a platform. In some embodiments, the support is a previously deposited portion of the 3D object.
In some embodiments, the support is a sacrificial object.

[0013] In another aspect, the present disclosure provides a method for printing at least a portion of a three-dimensional (3D) object adjacent to a support, comprising:
(a) directing a first portion of at least one wire toward and in contact with the support in accordance with at least one parameter; (b) upon contacting the at least one wire with the support, using one or more sensors to generate a signal(s) indicative of a reaction force exerted by the support against the at least the one wire, to provide a measured value; adjusting the at least one parameter in response to the measured value of the reaction force to provide at least one adjusted parameter; and bringing a second portion of the at least one wire toward and in contact with the support in accordance with the at least one adjusted parameter.

[0014] In some embodiments, the at least one parameter is adjusted when the reaction force exceeds a threshold value. In some embodiments, the method for printing at least a portion of the 3D object further comprises subjecting the second portion of the at least one wire to heating upon flow of electrical current through the at least one wire and into the support, or vice versa, which heating is sufficient to melt the second portion of the at least one wire. In some embodiments, the method for printing at least a portion of the 3D object further comprises depositing the second portion of the at least one wire on the support, thereby forming the at least the portion of the 3D object. In some embodiments, the first portion of the at least one wire is directed through a wire feeding assembly. In some embodiments, the at least one parameter is selected from the group consisting of a wire feed speed, distance between a tip of the at least one wire and the support, distance between the tip of the at least one wire and the at least the portion of the 3D object, amount of power applied to the wire feeding assembly, amount of current applied to the wire feeding assembly, and amount of voltage applied to the wire feeding assembly. In some embodiments, the one or more sensors are kinematically mounted to hold the wire feeding assembly. In some embodiments, the wire feeding assembly comprises a supporting wire guide and a wire feeder. In some embodiments, the supporting wire guide accepts the at least one wire from the wire feeder and directs the at least one wire towards the support. In some embodiments, the supporting wire guide is in contact with the wire feeder. In some embodiments, the one or more sensors comprise one or more strain gauges.

[0015] In some embodiments, prior to directing a first portion of at least one wire toward and in contact with the support, one or more sensors is calibrated. In some embodiments, the reaction force is measured in isolation from an upstream tension of the wire. In some embodiments, the first portion of the at least one wire is directed using a print head, and wherein generating a signal indicative of a reaction force exerted by the support comprises (i) determining an applied force applied by a gantry to the print head, and (ii) removing a weight of one or more printing components from the applied force to determine the reaction force. In some embodiments, the one or more printing components is selected from the group consisting of sensor, frame system, mount plate, drive motor, driver roller, preload motor, and preload roller. In some embodiments, the method for printing at least a portion of the 3D object further comprises prior to directing a first portion of at least one wire toward and in contact with the support, selecting the at least one parameter.

[0016] In another aspect of the present disclosure provides a system for printing at least a portion of the 3D object adjacent to a support, comprising: a support configured to hold the at least the portion of the 3D object; a source configured to hold at least one wire, which wire is usable for the printing of the at least the portion of the 3D object; one or more sensors configured to generate a signal(s) indicative of a reaction force of the support against the at least one wire; a power supply configured to flow electrical current through the at least one wire and the support;
and a controller operatively coupled to the power supply. In some embodiments, the controller is configured to: (i) direct a first portion of the at least one wire toward and in contact with the support in accordance with at least one parameter; (ii) upon contacting the at least one wire with the support, receive the signal(s) from the one or more sensors indicative of the reaction force exerted by the support against the first portion of the at least one wire to provide a measured value; (iii) adjust the at least one parameter in response to the measured value to provide at least one adjusted parameter; (iv) direct a second portion of the at least one wire toward and in contact with the support in accordance with the at least one adjusted parameter.

[0017] In some embodiments, the system for printing at least a portion of the 3D object, further comprises a wire feeding assembly comprising a supporting wire guide and a wire feeder.
In some embodiments, the supporting wire guide accepts the at least one wire from the wire feeder and directs the at least one wire towards the support. In some embodiments, the one or more sensors are kinematically mounted to hold the wire feeding assembly. In some embodiments, the supporting wire guide is in contact with the wire feeder. In some embodiments, the one or more sensors comprise one or more strain gauges. In some embodiments, the controller is configured to direct flow of electrical current through the second portion of the at least one wire and into the support, or vice versa, to subject the second portion of the at least one wire to heating, which heating is sufficient to melt the second portion of the at least one wire. In some embodiments, the controller is configured to direct the second portion of the at least one wire to be deposited on the support, thereby forming the at least the portion of the 3D object. In some embodiments, the controller is configured to measure the reaction force of the at least one wire in isolation of an upstream tension of the at least one wire. In some embodiments, the controller is configured to adjust the at least one parameter when the reaction force exceeds a threshold value.

[0018] Another aspect of the present disclosure provides a non-transitory computer readable medium comprising machine executable code that, upon execution by one or more computer processors, implements any of the methods above or elsewhere herein.

[0019] Another aspect of the present disclosure provides a system comprising one or more computer processors and computer memory coupled thereto. The computer memory comprises machine executable code that, upon execution by the one or more computer processors, implements any of the methods above or elsewhere herein.

[0020] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure.
Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
INCORPORATION BY REFERENCE

[0021] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.
To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.
BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings (also "Figure" and "FIG." herein), of which:

[0023] FIG. 1 schematically illustrates a force diagram of a wire feeder and the various forces acting on the wire as the wire is fed through a roller and preload configuration;

[0024] FIG. 2 illustrates an example sensor assembly comprising the wire feeding assembly;

[0025] FIG. 3 is a representation of the mass, spring, damper model;

[0026] FIG. 4 schematically illustrates a step response of the strain gauge force reading;

[0027] FIG. 5 schematically illustrates a graph used in response optimization from tuning of mass, spring, and damper parameters;

[0028] FIG. 6 schematically illustrates a theorized optimized step response;

[0029] FIG. 7 shows a computer system that is programmed or otherwise configured to implement methods provided herein;

[0030] FIG. 8 illustrates individual and sum calibration for a group of sensors for a series of loads;

[0031] FIG. 9 illustrates a second calibration using the wire back force mechanism on the printer;

[0032] FIG. 10 illustrates a system response while a feeder motor was powered but stationary and a hammer was used to hit the wire tip into the contact tip;

[0033] FIG. 11 shows measurements for the wire feeder driving wire, the sensor noise, and measurements of a friction load applied to the wire;

[0034] FIG. 12 shows measurements for the wire feeder driving wire and the sensor noise when a wire is freely driven;

[0035] FIG. 13 shows test data from printing a line while changing the extrusion ratio;

[0036] FIG. 14 illustrates the result of the test print, lined up with the data in FIG. 13;

[0037] FIG. 15 shows test data when printing corner turns;

[0038] FIG. 16 shows the amount of force read by the sensors when the wire is pushed with a specified feed length into a solid piece of metal;

[0039] FIG. 17 shows a focused view of the region between 4 and 5 on the x-axis of FIG.
16;

[0040] FIG. 18 illustrates the signal from the process of filling a hole when repairing a portion of the 3D object; and

[0041] FIG. 19 schematically illustrates an example of a wire feeding method.

DETAILED DESCRIPTION

[0042] While various embodiments of the invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions may occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed.

[0043] As used herein, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Any reference to "or" herein is intended to encompass "and/or" unless otherwise stated.

[0044] The term "welding," as used herein, generally refers to a method of heating at least a portion of a feedstock (e.g., a metal wire) to form a pool of molten liquid (e.g., molten metal) on an object (e.g., a metal object). The pool of molten liquid may cool and solidify on the object.
In some cases, the method may comprise heating the at least a portion of the feedstock and at least a portion of the object to form the pool of molten liquid.

[0045] The term "three-dimensional object" (also "3D object"), as used herein, generally refers to an object or a part that is printed by 3D printing. The 3D object may be at least a portion of a larger 3D object or an entirety of the 3D object.

[0046] The term "support," as used herein, generally refers to a structure that supports a nascent 3D object during printing and supports the 3D object after printing.
The support may be a platform or an object that may not be a platform, such as another 3D object.
The other object may be an object in need of repair or an object that is to be fused to another object (e.g., by a welding-type approach). The support may be a sacrificial object (e.g., one or more sacrificial layers) that may be removed from the 3D object after printing, or a previously formed portion of the 3D object, such as a previously formed (e.g., deposited) layer of the 3D
object.

[0047] The term "feedstock," as used herein, generally refers to a material that is usable alone or in combination with other material to print a 3D object. In some examples, the feedstock may be (i) a wire, ribbon or sheet, (ii) a plurality of wires, ribbons or sheets, or (iii) a combination of two or more of wires, ribbons and sheets (e.g., combination of wires and ribbons). The feedstock may comprise at least one of a polymer (e.g., thermoplastic), metal, metal alloy, ceramic, or a combination thereof In an example, the feedstock comprises a metal or a combination of metals (e.g., a metal alloy). As another example, the feedstock comprises a metal and a polymer (e.g., as a composite). The 3D printing may be performed with at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more feedstocks. The 3D printing may be performed with less than or equal to about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less feedstocks.

[0048] The term "guide" generally refers to a component in a print head that guides a feedstock towards a location on which a 3D object is to be printed, such as into a melt zone adjacent to a support. The melt zone may be on a support or at least a portion of a 3D object.
The guide may be a nozzle or a tip, for example. The guide may permit the feedstock to pass towards and in contact with the support. The guide may include an opening, and during use, the feedstock may be directed in contact with the guide through the opening and towards the support. As an alternative, the guide may not include an opening, but may include a surface that comes in contact with the feedstock. The feedstock may slide through, over or under the guide of the print head into the melt zone. The guide may make a sliding contact with the feedstock and conduct electrical current to or from the feedstock. The guide may constrain the feedstock radially. A position of the guide relative to the melt zone may be constrained while the feedstock is moving through the guide towards the melt zone.

[0049] In some cases, the term "guide" may generally refer to a component in a welding gun that guides a feedstock (e.g. a metal wire) towards a location on which welding may occur. The guide may be a nozzle, for example. The feedstock may be a welding electrode.

[0050] The term "roller", as used herein, generally refers to a part that may be in contact with a portion of a feedstock during printing. The roller may have various shapes and sizes. The roller may be circular, triangular, or square, for example. The roller may have at least one groove that is dimensioned to accommodate at least a portion of the feedstock.
The roller may have at least one protrusion to come in contact with at least a portion of the feedstock. The roller may direct movement and/or direction of the feedstock during printing. The roller may contact and supply a force to the feedstock to maintain a tension on the feedstock between a feedstock source to the guide.

[0051] Whenever the term "at least," "greater than," or "greater than or equal to" precedes the first numerical value in a series of two or more numerical values, the term "at least," "greater than" or "greater than or equal to" applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0052] Whenever the term "at most", "no more than," "less than," or "less than or equal to"
precedes the first numerical value in a series of two or more numerical values, the term "no more than," "less than," or "less than or equal to" applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.

[0053] The present disclosure provides methods and systems for forming a 3D
object. The 3D object may be based on a computer model of the 3D object, such as a computer-aided design (CAD) stored in a non-transitory computer storage medium (e.g., medium). As an alternative, the 3D object may not be based on any computer model. In such scenario, methods and systems of the present disclosure may be used to, for example, deposit material on another object, couple one object to at least another object (e.g., welding at least two objects together), or cure a defect in an object (e.g., fill a hole or other defect).
Printing Systems

[0054] In an aspect, the present disclosure provides a method for printing at least a portion of a three-dimensional (3D) object adjacent to a support. A first portion of at least one wire may be directed toward and in contact with the support using at least one parameter.
In other cases, prior to directing a first portion of the wire to the support, at least one parameter may be selected.
Upon contacting the at least one wire with the support, one or more sensors may be used to generate a signal(s) indicative of a reaction force exerted by the support against the at least one wire, to provide a measured value. The parameter may be adjusted in response to the measured value of the reaction force to provide an adjusted parameter. The measured reaction force may adjust the master or slave feeding system control, e.g. wire feed speed. The speed adjustment and control may be in real-time and may be continuous. In some cases, the parameter may be adjusted when the reaction force exceeds a threshold value to provide another adjusted parameter. Next, a second portion of the at least one wire may be brought toward and in contact with the support using the adjusted parameter.

[0055] The second portion of the at least one wire may be subjected to heating upon flow of electrical current through the at least one wire and into the support, or vice versa. The heating may be sufficient to melt the second portion of the at least one wire. The second portion of the at least one wire may be deposited on the support thereby forming at least a portion of the 3D
object. The first portion of the wire may be directed through a wire feeding assembly. The wire feeding assembly may comprise a supporting wire guide tube and a wire feeder.
The supporting wire guide may accept the wire from the wire feeder and direct the wire towards the support. The supporting wire guide tube may press against the wire feeder.

[0056] The reaction force or back-force measurement may be used as a feedback to the process control system. This control system may control the quality of the print, and the reaction force or back-force on the tip of the wire may be one of several key inputs to the control system.
For example, if the back-force increases above a certain set point, the control system can apply more power or slow down the motion system to accommodate. In some cases, the force sensor may be used to predict and prevent sparks, which can reduce the print quality.

[0057] The parameter may be a wire feed speed and/or amount of power and/or current and/or voltage applied to the wire feeding assembly. In some cases, the parameter may be the distance between the tip of the wire and the previously printed part or the distance between the wire guide and the support. In other cases, prior to directing the first portion of the wire toward and in contact with the support, the one or more sensors may be calibrated.
The calibration may be one point calibration, two point calibration, or multipoint calibration.

[0058] In some cases, the wire back force or reaction force is measured in isolation from the upstream tension of the wire. The upstream tension in the wire may be removed by the supporting wire guide tube pressing on the wire feeder. The reaction force may be measured by isolating a force of friction through a wire guide tube from a force that a feed hob imposes on the at least one wire. The feed hob may comprise a preload and driver roller. In some cases, the first portion of the wire may be directed using a print head and measuring the reaction force comprises (i) determining an applied force applied by a gantry to the print head and (ii) removing a weight of one or more printing components from the applied force to determine the reaction force. The one or more printing components may be selected from the group consisting of sensor, frame system, mount plate, drive motor, driver roller, preload motor, and preload roller. The wire may be held by the preload and driver rollers. The force that the wire exerts on the sensor, e.g. load cells, may be determined. While holding the wire, the sensors may comprise static mass of various components, such as the motors and brackets. Without considering the static mass, the load cell reading may be isolated.

[0059] The sensor may be selected from the group consisting of force gauge, load cell, piezoelectric sensor, strain gauge, torque sensor, contact sensor, linear variable differential, and non-contact sensor. In some cases, the sensors may comprise one or more load cells. The sensors may be kinematically mounted to the wire feeding assembly. The one or more load cells can be hydraulic, pneumatic, or based on strain gauges. The one or more sensors may be strain gauges.
There may be at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more sensors. In other cases, there are less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less sensors.

[0060] In some examples, the one or more sensors are attached to the wire feeding assembly in a manner such that the forces on each of the one or more sensors include the force of gravity and a reactionary force (e.g., as may be imparted upon a feedstock coming in contact with surface). This may advantageously permit the reactionary force to be isolated from other forces that may be imparted on each of the one or more sensors. Such kinematic mounting may be achieved, for example, by attaching a sensor to a supporting platform that also supports other components of the wire feeding assembly.

[0061] FIG. 1 illustrates an example force diagram of a wire feeder 100, showing various forces acting on a wire 105 as the wire 105 is fed through a preload roller 120 and a driver roller 135 toward a support 140. The wire 105 may be fed using a parameter, e.g. wire speed or amount of power. A preload force 115 may be applied to the preload roller 120 to press the wire 105 into the driver roller 135, which applies a traction force 125 along the length of the wire 105 to move the wire 105. The driver roller 135 may comprise a drive torque 130 causing its rotation. Upon contact with the support 140, a reaction force 145 exerted by the support 140 against the wire 105 may be measured. In some cases, the traction force 125 applied on the wire 105 may be equal to the upstream tension plus the downstream compression. The downstream compression may be the reaction force 145. The upstream tension may be the traction force 125. In other cases, the reaction force 145 may be measured in isolation of the upstream tension.

[0062] In another aspect, the present disclosure provides a system for printing at least a portion of the 3D object adjacent to a support. The system may comprise a support configured to hold at least the portion of the 3D object, a source configured to hold the at least one wire, one or more sensors configured to generate a signal(s) indicative of a reaction force of the support against the at least one wire, and a power supply configured to electrical current through the wire and the support. The wire may be used for printing of at least a portion of the 3D object.
Furthermore, a controller may be operatively coupled to the power supply. The controller may be configured to (i) direct a first portion of the at least one wire toward and in contact with the support in accordance with at least one parameter; (ii) upon contacting at least one wire with the support, receive the signal(s) from the one or more sensors indicative of the reaction force exerted by the support against the first portion of the at least one wire to provide a measured value; (iii) adjust the at least one parameter in response to the measured value to provide at least one adjusted parameter; (iv) direct a second portion of the at least one wire toward and in contact with the support in accordance with the at least one adjusted parameter. In some cases, the controller may be configured to adjust the parameter when the reaction force exceeds a threshold value.

[0063] The threshold may be a pre-determined threshold value or range of the force. The threshold may be a force acceptable by the wire without experiencing significant damage (e.g., deformation or cut). The threshold may be a force acceptable by the support without experiencing a significant damage (e.g., deformation or cut). The threshold may be specific for a type of material the wire is made of Alternatively or in addition to, the threshold may be a common threshold for different types of materials that different wires are made of.

[0064] FIG. 2 illustrates an example of a sensor assembly 200 comprising a wire 205, a wire guide 210, a mount 215, load cells 220, a wire feeding assembly 225, a preload roller 230 and a driver roller 235. The wire guide 210 may be for directing the wire 205 towards a support 240.
The at least one wire guide 210 may include a tube for guiding the wire 205.
The support 240 may include a melting zone 245, which may be formed, for example, upon the flow of electrical current through the wire 205 and into the support 240, or vice versa. The wire 205 may be driven toward the support 240 using a preload roller 230 and a driver roller 235. The wire guide 201 can press against the wire feeding assembly 225. The wire 205 may comprise a tip end that comes in contact with the support 240. As the wire feeding assembly 225 directs the wire 205 into the melt zone 245, the load cell sensors 220 can sense a reactionary force generated upon the wire 205 coming in contact with the support 240. The load cells 220 may be attached to the mount plate 215. The load cells 220 may be positioned symmetrically from the wire guide 210, and each of the load cells 220 can detect an equal amount of force. The load cells 220 may be kinematically mounted to the wire feeding assembly 225, such as through attachment to the mount plate 215. The mount plate 215 in turn can support the preload roller 230 and the driver roller 235. In some cases, weight is minimized so that the mount plate 215 supports components of the wire feeding assembly 225, such as the preload roller 230 and the driver roller 235. As a result, weights (or forces upon) other components (e.g., the wire guide 210) may not be measured or off set by the load cells 220. The signal to noise ratio may be used as an indicator of how well the sensor assembly is operating.

[0065] The preload roller 230 may include a motor for rotating the preload roller 230. As an alternative or in addition to, the driver roller 235 may include a motor for rotating the driver roller 235.

[0066] In some cases, the controller is configured to direct flow of electrical current through the second portion of the wire and into the support, or vice versa, to subject the second portion of the at least one wire to heating, which heating is sufficient to melt the second portion of the wire.
For example, the controller can direct a power supply to flow electrical current through the wire and into the support, or vice versa. This may subject the wire to heating (e.g., Joule heating), which may be sufficient to melt the second portion. The controller may be configured to direct the second portion of the wire to be deposited on the support, thereby forming at least a portion of the 3D object.

[0067] A traction force may be required to direct the feedstock towards the guide. Thus, the gap between the driver roller and the preload roller may be sufficiently small so that the feedstock is (i) in contact with the two rollers and (ii) compressed between the two rollers. The force, e.g. a normal force, due to compression and the friction between the feedstock and the driver roller may produce the traction force at one or more contact surfaces between the feedstock and the driver roller. The traction force may be a contact force.
The traction force in combination with the rotation of the driver roller may be sufficient to direct movement of the feedstock towards or away from the guide.

[0068] In some cases, the wire back force or reaction force is measured in isolation from the upstream tension of the wire. The upstream tension in the wire may be removed by the supporting wire guide tube pressing on the wire feeder. The wire back force or reaction force can be measured through a variety of approaches and with different types of sensors, such as kinematically mounted strain gauges that support the wire feeding mechanism.
The sensor may be selected from the group consisting of force gauge, load cell, piezoelectric sensor, strain gauge, torque sensor, contact sensor, linear variable differential, and non-contact sensor. When force is applied to the tip of the wire, the wire back force mechanism (WFS) can sense the reaction force of the wire on the wire feeder. In some cases, there may be three sensors assembled in a kinematic fashion that hold the wire feeding mechanism. In other cases, there is at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more sensors. Alternatively, there may be less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less sensors.

[0069] The system may comprise a feedstock source configured to hold a feedstock. The feedstock may be usable for printing the 3D object. The system may comprise a print head comprising a guide. The guide may direct the feedstock from the feedstock source towards and in contact with a support or at least a portion of the 3D object adjacent to the support. The guide may also direct the feedstock in a direction away from the guide towards the feedstock source.
The system may comprise a driver roller configured to come in contact with the feedstock. The driver roller may be coupled to an actuator that subjects the driver roller to rotation to direct the feedstock towards the guide. The system may comprise a preload roller adjacent to the driver roller. The preload roller may be configured to come in contact with the feedstock at a position adjacent to the driver roller. The preload roller and the driver roller may be separated by a gap.
A size of the gap may be adjustable to permit the feedstock to be directed through the gap. The system may comprise a power source in electrical communication with the feedstock and the support. The power source may be configured to supply electrical current from the guide through the feedstock and to the support, or vice versa, during printing the at least a portion of the 3D object. The system may also comprise a controller in electrical communication with the power source. The controller may be configured to direct adjustment of the size of the gap. The controller may be configured to direct the actuator coupled to the driver roller to direct the feedstock through the gap and towards the guide. The controller may be configured to direct the power source to supply the electrical current from the guide through the feedstock and to the support, or vice versa, during printing under conditions sufficient to melt the feedstock when the feedstock is in contact with the support or the portion of the 3D object.

[0070] The print head may move relative to the support. The print head may further comprise a mechanical gantry capable of motion in one or more axes of control (e.g., one or more of the XYZ planes or rotational axes) via one or more actuators. In some cases, the mechanical gantry may be capable of motion in 6-axis of control. Many actuators may accomplish the required motion, including electric, hydraulic or pneumatic motors, linear actuators, belts, pulleys, lead screws, and other devices. The one or more actuators of the print head may be operatively connected to the controller. The controller may direct movement of the print head during printing the at least the portion of the 3D object. In some examples, the system may comprise a plurality of assemblies. The system may include at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more assemblies. The system may include less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less assemblies.

[0071] The assembly may be a pusher assembly (a "slave" assembly) that pushes the feedstock from the feedstock source towards to guide. In some cases, the system may include a plurality of the assembly for each feedstock source of a plurality of feedstock sources.
Alternatively or in addition to, the system may include an additional assembly adjacent to the guide. The additional assembly may be a puller assembly (a "master" assembly) that pulls the feedstock into the guide. The first roller of the assembly may have a groove to accept at least a portion of the feedstock. The first roller may include at least one additional groove adjacent to the groove. The at least one additional groove may be arranged in a parallel fashion to the groove. The at least one additional groove may accept at least a portion of at least one additional feedstock. The groove and the at least one additional groove may have different dimensions (e.g., widths, depths, etc.) and/or geometries. The first roller may include at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more grooves. The first roller may include less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less assemblies.

[0072] The first roller comprising the at least one additional groove may be coupled (e.g., mechanically attached) to a position adjusting mechanism. The position adjusting mechanism may move the first roller into and out of alignment with the feedstock or the at least one additional feedstock. The position adjusting mechanism may be one or more actuators (e.g., one or more linear screw actuators). The position adjusting mechanism may be a manual user operation or the controller automated process. In some cases, the controller may be in communication with the position adjusting mechanism to direct the position adjusting mechanism to move the first roller during the alignment with the feedstock or the at least one additional feedstock. In some examples, the position adjusting mechanism comprises a stage for holding at least the driver roller. The stage may further have one or more linear actuators that are mechanically attached to the stage.

[0073] In some cases, the first roller with the groove may be a driver roller that is coupled to an actuator that subjects the driver roller to rotate and direct the feedstock towards the guide.
The second roller, with or without the protrusion, may be a preload roller that presses at least a portion of the feedstock towards the driver roller. In some cases, the second roller, with or without the protrusion, may be a driver roller that is coupled to an actuator that subjects the driver roller to rotate and direct the feedstock towards the guide. The first roller with the groove may be a preload roller that presses at least a portion of the feedstock towards the driver roller.

[0074] The actuator may be a rotational actuator or an electric motor. A
rotation may feed the feedstock along a direction away from the feedstock source towards the guide. Alternatively or in addition to, the rotation may direct the feedstock along a direction away from the guide towards the feedstock source. The actuator may rotate the driver roller at a plurality of rotating speeds. The actuator may be configured to accelerate, decelerate, maintain at a given speed of the plurality of rotating speeds, or control a direction of rotation of the driver roller. The actuator may be in communication with the controller. The controller may direct the actuator to rotate the driver roller. In some cases, the actuator of the driver roller may comprise an encoder. The controller may be operatively coupled to the encoder of the actuator of the driver roller to monitor operating velocities of the driver roller.

[0075] The system may comprise one or a plurality of driver rollers. The system may include at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more driver rollers.
The system may include less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less driver rollers.
Each driver roller may be independently coupled to an actuator (e.g., motor) for subjecting a rotational movement, and each actuator may be independently or collectively in communication with one or more controllers. As an alternative, at least some of the driver rollers may be coupled to the same actuator.

[0076] The preload roller may be configured to (i) come in contact with at least a portion of the feedstock at a position adjacent to the driver roller and (ii) direct the at least the portion of the feedstock towards the driver roller. The preload roller may comprise an outer shell and an inner shell. The outer shell and the inner shell may move independently from each other. An outer circumference of the outer shell may come in contact with the portion of the wire. The preload roller may further comprise a bearing assembly disposed between the outer shell and the inner shell. The bearing assembly may facilitate the rotational motion of the outer shell with respect to the inner shell during directing the portion of the feedstock towards or away from the guide. The bearing assembly may facilitate the outer shell to roll with very little rolling resistance. A rolling element in the bearing assembly may be a ball bearing, a roller bearing, a gear bearing, etc. The bearing assembly may be lubricated with a viscous lubricant to facilitate the rotational motion of the outer shell of the preload roller. The viscous lubricant may remain inside the bearing assembly.

[0077] The system may comprise one or a plurality of preload rollers. In some cases, the preload roller may be coupled to an actuator. In other cases, the preload roller may not be coupled to an actuator but may spin upon movement of the wire. The system may include at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more preload rollers. The system may include less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less preload rollers.

[0078] The 3D printing may be performed with at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more feedstocks. The 3D printing may be performed with less than or equal about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less feedstocks. In some cases, a plurality of feedstocks may be used to print a layer of the 3D object. The feedstock may be (i) a wire, ribbon or sheet, (ii) a plurality of wires, ribbons or sheets, or (iii) a combination of two or more of wires, ribbons and sheets (e.g., combination of wires and ribbons). The feedstock may have other form factors.
If multiple feedstocks are used, the multiple feedstocks may be brought together to the opening.
Alternatively or in addition to, at least some or each of the multiple feedstocks may be directed to the opening or different openings. A cross-sectional diameter of the feed stock may be at least about 0.01 millimeters (mm), 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm or more. Alternatively, the cross-sectional diameter may be less than or equal to about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4.0 mm, 3.5 mm, 3.0 mm, 2.5 mm, 2.0 mm, 1.5 mm, 1.0 mm, 0.5 mm, 0.45 mm, 0.4 mm, 0.35 mm, 0.3 mm, 0.25 mm, 0.2 mm, 0.15 mm, 0.1 mm, 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm, 0.05 mm, 0.04 mm, 0.03 mm, 0.02 mm, 0.01 mm or less.

[0079] The feedstock receiver may be a guide (e.g., a nozzle) of a welding gun for welding (e.g., gas metal arc welding, flux-cored arc welding, etc.). The feedstock receiver may be a guide (e.g. a nozzle) of a printing head in a device for printing a 3D object.
The feedstock may be usable for printing the 3D object. The feedstock may be formed of at least one metal. In some examples, the feedstock comprises one or more metals selected from the group consisting of steel, stainless steel, iron, copper, gold, silver, cobalt, chromium, nickel, titanium, platinum, palladium, titanium, and aluminum. The feedstock may include at least one non-metal, such as a fiber material (e.g., elemental fiber or nanotube) and/or polymeric material.
The fiber material may include, for example, carbon fiber, carbon nanotubes, and/or graphene.
Alternatively, the feedstock may include at least one natural or synthetic ceramic material. The natural or synthetic ceramic material may be calcium phosphate, calcium carbonate, or silicate.

[0080] The feedstock may comprise at least one of polymers, metals, metal alloys, ceramics, or mixtures thereof. In some cases, the polymers may be thermoplastics.
Examples of thermoplastics include acrylate or methylmethacrylate polymers or copolymers (e.g., polyacrylates, polymethylmethacrylates, etc.); polylactic acid (PLA) polymers;

polyhydroxyalkanoate (PHA) polymers (e.g., polyhydroxybutyrate (PHB));
polycaprolactone (PCL) polymers; polyglycolic acid polymers; acrylonitrile-butadiene-styrene polymers (ABS);
polyvinylidene fluoride polymers; polyurethane polymers; polyolefin polymers (e.g., polyethylene, polypropylene, etc.); polyester polymers; polyalkylene oxide polymers (e.g., polyethylene oxide (PEO)); polyvinyl alcohol (PVA) polymers; polyamide polymers;
polycarbonate polymers; high impact polystyrene (HIPS) polymers; polyurethane polymers, or mixtures thereof.

[0081] Segments (e.g. particles) of the feedstock may be printed on the support by melting a tip of the feedstock with an electric current. The electric current may flow from the guide of the print head through the feedstock and to the support, or vice versa. When the tip of the feedstock is in contact with the support, an electric circuit comprising the guide of the print head, the feedstock, the support, and a power source may be formed. The controller may be operatively coupled to the power source. In such electric circuit, the feedstock may be a first electrode, and the support may be a second electrode. If the feedstock is in physical contact with the support and the power source supplies the electrical current from the guide through the feedstock and to the support, or vice versa, the feedstock and the support are in electrical contact. In the electrical contact, there may be an electrical resistance between the feedstock and the support (i.e., contact resistance) due to a small surface area of the feedstock and microscopic imperfections on a surface of the tip of the feedstock and/or a surface of the support. The contact resistance between the tip of the feedstock and the support may heat a local area at the contact according to Equation 1 (i.e., Joule's First Law):
Q = 12 = R = t (Equantion 1) where Q is the heat generated at the local area at the contact, / is the electric current, R is the contact resistance between the feedstock and the support, and t is a duration of an application of the current.

[0082] The heat generated at the local area at the contact between the feedstock and the support may be sufficient to melt the tip of the feedstock into a segment and to fuse the segment to the support. The heat may be generated by resistive heating (e.g., Joule heating). In some examples, the segment is a strand or a particle. The strand or particle may be molten. Upon deposition of the segment on the support, the segment may act as a second electrode in the electric circuit to melt and print additional segments of the feedstock. The heat generated at the local area may be sufficient to melt the tip of the feedstock into a segment and to fuse the segment to a segment on the support. The heat generated at the local area may be sufficient to melt the tip of the feedstock into a segment and to fuse the segment to one or more neighboring segments. As such, segments of the feedstock may be deposited without use or generation of electric arcs and/or plasma, but rather by utilizing energy (e.g., electrical energy) within the feedstock. The energy within the feedstock may be to (i) melt at least a portion of the feedstock and (ii) print and/or repair at least a portion of the 3D object.

[0083] The tip of the feedstock may melt while the feedstock is in contact with the support and the feedstock and the support are moving relative to one another. For example, the feedstock is moving and the support is stationary. As another example, the feedstock is stationary and the support is moving (e.g., along a plane orthogonal to a longitudinal axis of the support perpendicular to the support). As another example, both the feedstock and the support are moving (e.g., along a plane orthogonal to a longitudinal axis of the support perpendicular to the support).

[0084] The support may be a printing platform. As an alternative, the support may be a previously deposited portion (e.g., previously deposited layer), such as a previously deposited layer of the three-dimensional object or a previously deposited sacrificial layer(s). The support may be a sacrificial object (e.g., one or more sacrificial layers). As another alternative, the support may be a part (e.g., part formed by 3D printing or other approaches) and the feedstock may be deposited on the part.

[0085] The heat generated at a point of contact between the feedstock (e.g., a wire) and the support may be such that the feedstock and/or the melt generated from the feedstock has a temperature of at least about 100 degrees Celsius ( C), 200 C, 300 C, 400 C, 500 C, 600 C, 700 C, 800 C, 900 C, 1000 C, 1100 C, 1200 C, 1300 C, 1400 C, 1500 C, 1600 C, 1700 C, 1800 C, 1900 C, 2000 C, 2100 C, 2200 C, 2300 C, 2400 C, 2500 C, 2600 C, 2700 C, 2800 C, 2900 C, 3000 C, 3100 C, 3200 C, 3300 C, 3400 C, 3500 C, 3600 C, 3700 C, 3800 C, 3900 C, 4000 C, 5000 C or more. The temperature may be at most about 5000 C, 4000 C, 3900 C, 3800 C, 3700 C, 3600 C, 3500 C, 3400 C, 3300 C, 3200 C, 3100 C, 3000 C, 2900 C, 2800 C, 2700 C, 2600 C, 2500 C, 2400 C, 2300 C, 2200 C, 2100 C, 2000 C, 1900 C, 1800 C, 1700 C, 1600 C, 1500 C, 1400 C, 1300 C, 1200 C, 1100 C, 1000 C, 900 C, 800 C, 700 C, 600 C, 500 C, 400 C, 300 C, 200 C, 100 C, or less.

[0086] In some examples, the temperature may be at least about 400 C, 410 C, 420 C, 430 C, 440 C, 450 C, 460 C, 470 C, 480 C, 490 C, 500 C, 510 C, 520 C, 530 C, 540 C, 550 C, 560 C, 570 C, 580 C, 590 C, 600 C, 610 C, 620 C, 630 C, 640 C, 650 C, 660 C, 670 C, 680 C, 690 C, 700 C, 710 C, 720 C, 730 C, 740 C, 750 C, 760 C, 770 C, 780 C, 790 C, 800 C, 810 C, 820 C, 830 C, 840 C, 850 C, 860 C, 870 C, 880 C, 890 C, 900 C, 910 C, 920 C, 930 C, 940 C, 950 C, 960 C, 970 C, 980 C, 990 C, 1000 C, 1110 C, 1120 C, 1130 C, 1140 C, 1150 C, 1160 C, 1170 C, 1180 C, 1190 C, C, 1210 C, 1220 C, 1230 C, 1240 C, 1250 C, 1260 C, 1270 C, 1280 C, 1290 C, 1300 C, or more when the feedstock comprises aluminum or alloys. The temperature may be at most about 1300 C, 1290 C, 1280 C, 1270 C, 1260 C, 1250 C, 1240 C, 1230 C, 1220 C, 1210 C, 1200 C, 1190 C, 1180 C, 1170 C, 1160 C, 1150 C, 1140 C, 1130 C, 1120 C, C, 1100 C, 1090 C, 1080 C, 1070 C, 1060 C, 1050 C, 1040 C, 1030 C, 1020 C, C, 1000 C, 990 C, 980 C, 970 C, 960 C, 950 C, 940 C, 930 C, 920 C, 910 C, 900 C, 890 C, 880 C, 870 C, 860 C, 850 C, 840 C, 830 C, 820 C, 810 C, 800 C, 790 C, 780 C, 770 C, 760 C, 750 C, 740 C, 730 C, 720 C, 710 C, 700 C, 690 C, 680 C, 670 C, 660 C, 650 C, 640 C, 630 C, 620 C, 610 C, 600 C, 590 C, 580 C, 570 C, 560 C, 550 C, 540 C, 530 C, 520 C, 510 C, 500 C, 490 C, 580 C, 470 C, 460 C, 450 C, 440 C, 430 C, 420 C, 410 C, 400 C, or less when the feedstock comprises aluminum or alloys.

[0087] In some examples, the temperature may be at least about 800 C, 810 C, 820 C, 830 C, 840 C, 850 C, 860 C, 870 C, 880 C, 890 C, 900 C, 910 C, 920 C, 930 C, 940 C, 950 C, 960 C, 970 C, 980 C, 990 C, 1000 C, 1010 C, 1020 C, 1030 C, 1040 C, 1050 C, 1060 C, 100 C, 1080 C, 1090 C, 1100 C, 1110 C, 1120 C, 1130 C, 1140 C, 1150 C, 1160 C, 1170 C, 1180 C, 1190 C, 1200 C, 1210 C, 1220 C, 1230 C, 1240 C, 1250 C, 1260 C, 1270 C, 1280 C, 1290 C, 1300 C, 1310 C, 1320 C, 1330 C, 1340 C, 1350 C, 1360 C, 1370 C, 1380 C, 1390 C, 1400 C, 1410 C, 1420 C, 1430 C, 1440 C, 1450 C, 1460 C, 1470 C, 1480 C, 1490 C, 1500 C, 1510 C, 1520 C, 1530 C, 1540 C, 1550 C, 1560 C, 1570 C, 1580 C, 1590 C, 1600 C, or more when the feedstock comprises copper or alloys. The temperature may be at most about 1600 C, 1590 C, 1580 C, 1570 C, 1560 C, 1550 C, 1540 C, 1530 C, 1520 C, 1510 C, 1500 C, 1490 C, 1480 C, 1470 C, 1460 C, 1450 C, 1440 C, 1430 C, 1420 C, 1410 C, 1400 C, 1390 C, 1380 C, 1370 C, 1360 C, 1350 C, 1340 C, 1330 C, 1320 C, 1310 C, 1300 C, 1290 C, 1280 C, 1270 C, 1260 C, 1250 C, 1240 C, 1230 C, 1220 C, 1210 C, 1200 C, 1190 C, 1180 C, 1170 C, 1160 C, 1150 C, 1140 C, 1130 C, 1120 C, 1110 C, 1100 C, 1090 C, 1080 C, 1070 C, 1060 C, 1050 C, 1040 C, 1030 C, 1020 C, 1010 C, 1000 C, 990 C, 980 C, 970 C, 960 C, 950 C, 940 C, 930 C, 920 C, 910 C, 900 C, 890 C, 880 C, 870 C, 860 C, 850 C, 840 C, 830 C, 820 C, 810 C, 800 C, or less when the feedstock comprises copper or alloys.

[0088] In some examples, the temperature may be at least about 800 C, 810 C, 820 C, 830 C, 840 C, 850 C, 860 C, 870 C, 880 C, 890 C, 900 C, 910 C, 920 C, 930 C, 940 C, 950 C, 960 C, 970 C, 980 C, 990 C, 1000 C, 1010 C, 1020 C, 1030 C, 1040 C, 1050 C, 1060 C, 1070 C, 1080 C, 1090 C, 1100 C, 1110 C, 1120 C, 1130 C, 1140 C, 1150 C, 1160 C, 1170 C, 1180 C, 1190 C, 1200 C, 1210 C, 1220 C, 1230 C, 1240 C, 1250 C, 1260 C, 1270 C, 1280 C, 1290 C, 1300 C, 1310 C, 1320 C, 1330 C, 1340 C, 1350 C, 1360 C, 1370 C, 1380 C, 1390 C, 1400 C, 1410 C, 1420 C, 1430 C, 1440 C, 1450 C, 1460 C, 1470 C, 1480 C, 1490 C, 1500 C, 1510 C, 1520 C, 1530 C, 1540 C, 1550 C, 1560 C, 1570 C, 1580 C, 1590 C, 1600 C, or more when the feedstock comprises gold or alloys. The temperature may be at most about 1600 C, 1590 C, 1580 C, 1570 C, 1560 C, 1550 C, 1540 C, 1530 C, 1520 C, 1510 C, 1500 C, 1490 C, 1480 C, 1470 C, 1460 C, 1450 C, 1440 C, 1430 C, 1420 C, 1410 C, 1400 C, 1390 C, 1380 C, 1370 C, 1360 C, 1350 C, 1340 C, 1330 C, 1320 C, 1310 C, 1300 C, 1290 C, 1280 C, 1270 C, 1260 C, 1250 C, 1240 C, 1230 C, 1220 C, 1210 C, 1200 C, 1190 C, 1180 C, 1170 C, 1160 C, 1150 C, 1140 C, 1130 C, 1120 C, 1110 C, 1100 C, 1090 C, 1080 C, 1070 C, 1060 C, 1050 C, 1040 C, 1030 C, 1020 C, 1010 C, 1000 C, 990 C, 980 C, 970 C, 960 C, 950 C, 940 C, 930 C, 920 C, 910 C, 900 C, 890 C, 880 C, 870 C, 860 C, 850 C, 840 C, 830 C, 820 C, 810 C, 800 C, or less when the feedstock comprises gold or alloys.

[0089] In some examples, the temperature may be at least about 810 C, 820 C, 830 C, 840 C, 850 C, 860 C, 870 C, 880 C, 890 C, 900 C, 910 C, 920 C, 930 C, 940 C, 950 C, 960 C, 970 C, 980 C, 990 C, 1000 C, 1050 C, 1100 C, 1150 C, 1200 C, 12050 C, 1300 C, 1350 C, 1400 C, 1450 C, 1500 C, 1550 C, 1600 C, 1650 C, 1700 C, 1750 C, 1800 C, 1850 C, 1900 C, 1950 C, 2000 C, 2050 C, 2100 C, 2150 C, 2200 C, 2250 C, 2300 C, 2350 C, 2400 C, 2450 C, 2500 C, or more when the feedstock comprises iron or alloys. The temperature may be at most about 2500 C, 2450 C, 2400 C, 2350 C, 2300 C, 2250 C, 2200 C, 2150 C, 2100 C, 2050 C, 2000 C, 1900 C, 1800 C, 1700 C, 1600 C, 1500 C, 1400 C, 1300 C, 1200 C, 1100 C, 1000 C, 990 C, 980 C, 970 C, 960 C, 950 C, 940 C, 930 C, 920 C, 910 C, 900 C, 890 C, 880 C, 870 C, 860 C, 850 C, 840 C, 830 C, 820 C, 810 C, 800 C, or less when the feedstock comprises iron or alloys.

[0090] In some examples, the temperature may be at least about 1500 C, 1510 C, 1520 C, 1530 C, 1540 C, 1550 C, 1560 C, 1570 C, 1580 C, 1590 C, 1600 C, 1610 C, 1620 C, 1630 C, 1640 C, 1650 C, 1660 C, 1670 C, 1680 C, 1690 C, 1700 C, 1710 C, 1720 C, 1730 C, 1740 C, 1750 C, 1760 C, 1770 C, 1780 C, 1790 C, 1800 C, 1850 C, 1900 C, 1950 C, 2000 C, 2050 C, 2100 C, 2150 C, 2200 C, 2250 C, 2300 C, or more when the feedstock comprises platinum or alloys. The temperature may be at most about 2300 C,2250 C,2200 C,2150 C,2100 C, 2050 C,2000 C,1950 C,1900 C,1850 C,1800 C, 1790 C, 1780 C, 1770 C, 1760 C, 1750 C, 1740 C, 1730 C, 1720 C, 1710 C, 1700 C, 1690 C, 1680 C, 1670 C, 1660 C, 1650 C, 1640 C, 1630 C, 1620 C, 1610 C, 1600 C, 1590 C, 1580 C, 1570 C, 1560 C, 1550 C, 1540 C, 1530 C, 1520 C, 1510 C, 1500 C, or less when the feedstock comprises platinum or alloys.

[0091] In some examples, the temperature may be at least about 1300 C, 1310 C, 1320 C, 1330 C, 1340 C, 1350 C, 1360 C, 1370 C, 1380 C, 1390 C, 1400 C, 1410 C, 1420 C, 1430 C, 1440 C, 1450 C, 1460 C, 1470 C, 1480 C, 1490 C, 1500 C, 1510 C, 1520 C, 1530 C, 1540 C, 1550 C, 1560 C, 1570 C, 1580 C, 1590 C, 1600 C, 1610 C, 1620 C, 1630 C, 1640 C, 1650 C, 1660 C, 1670 C, 1680 C, 1690 C, 1700 C, 1710 C, 1720 C, 1730 C, 1740 C, 1750 C, 1760 C, 1770 C, 1780 C, 1790 C, 1800 C, 1850 C, 1900 C, 1950 C, 2000 C, 2050 C, 2100 C, 2150 C, 2200 C, 2250 C, 2300 C, 2350 C, 2400 C, or more when the feedstock comprises titanium or alloys. The temperature may be at most about 2400 C, 2350 C, 2300 C, 2250 C, 2200 C, 2150 C, 2100 C, 2050 C,2000 C,1950 C,1900 C,1850 C,1800 C, 1790 C, 1780 C, 1770 C, 1760 C, 1750 C, 1740 C, 1730 C, 1720 C, 1710 C, 1700 C, 1690 C, 1680 C, 1670 C, 1660 C, 1650 C, 1640 C, 1630 C, 1620 C, 1610 C, 1600 C, 1590 C, 1580 C, 1570 C, 1560 C, 1550 C, 1540 C, 1530 C, 1520 C, 1510 C, 1500 C, 1490 C, 1480 C, 1470 C, 1460 C, 1450 C, 1440 C, 1430 C, 1420 C, 1410 C, 1400 C, 1390 C, 1380 C, 1370 C, 1360 C, 1350 C, 1340 C, 1330 C, 1320 C, 1310 C, 1300 C, or less when the feedstock comprises titanium or alloys.

[0092] In some examples, the temperature may be at least about 1200 C, 1210 C, 1220 C, 1230 C, 1240 C, 1250 C, 1260 C, 1270 C, 1280 C, 1290 C, 1300 C, 1310 C, 1320 C, 1330 C, 1340 C, 1350 C, 1360 C, 1370 C, 1380 C, 1390 C, 1400 C, 1410 C, 1420 C, 1430 C, 1440 C, 1450 C, 1460 C, 1470 C, 1480 C, 1490 C, 1500 C, 1510 C, 1520 C, 1530 C, 1540 C, 1550 C, 1560 C, 1570 C, 1580 C, 1590 C, 1600 C, 1650 C, 1700 C, 1750 C, 1800 C, 1850 C, 1900 C, 1950 C, 2000 C, 2050 C, 2100 C, or more when the feedstock comprises steel (e.g., carbon steel, stainless steel, etc.) or alloys. The temperature may be at most about 2100 C, 2050 C, 2000 C, 1950 C, 1900 C, 1850 C, 1800 C, 1750 C, 1700 C, 1650 C, 1600 C, 1590 C, 1580 C, 1570 C, 1560 C, 1550 C, 1540 C, 1530 C, 1520 C, 1510 C, 1500 C, 1490 C, 1480 C, 1470 C, 1460 C, 1450 C, 1440 C, 1430 C, 1420 C, 1410 C, 1400 C, 1390 C, 1380 C, 1370 C, 1360 C, 1350 C, 1340 C, 1330 C, 1320 C, 1310 C, 1300 C, 1290 C, 1280 C, 1270 C, 1260 C, 1250 C, 1240 C, 1230 C, 1220 C, 1210 C, 1200 C, or less when the feedstock comprises steel or alloys.

[0093] In some cases, the heat generated at the local area at the contact between the feedstock and the support may not vary depending on a material of the feedstock (e.g., the wire).
Alternatively, the heat generated at the local area at the contact between the feedstock and the support may vary depending on the material of the feedstock.

[0094] In some embodiments, based at least in part on a type or composition of the alloy, the melting point of the alloy may be lower than a melting temperature of one or more base metals of the alloy. Alternatively, based at least in part on a type or composition of the alloy, the melting point of the alloy may be higher than the melting temperature of the one or more base metals of the alloy. As another alternative, based at least in part on a type or composition of the alloy, the melting point of the alloy may be about the same as the melting temperature of the one or more base metals of the alloy. In some embodiments, the feedstock (e.g. a wire) may superheat at a melt pool.

[0095] The electric current from the guide to the feedstock and to the support, or vice versa, may range from about 10 Amperes (A) to about 20000 A. The electric current may be at least about 10 A, 20 A, 30 A, 40 A, 50 A, 60 A, 70 A, 80 A, 90 A, 100 A, 200 A, 300 A, 400 A, 500 A, 600 A, 700 A, 800 A, 900 A, 1000 A, 2000 A, 3000 A, 4000 A, 5000 A, 6000 A, 7000 A, 8000 A, 9000 A, 10000 A, 20000 A, or more. The electric current may be less than or equal about 20000 A, 10000 A, 9000 A, 8000 A, 7000 A, 6000 A, 5000 A, 4000 A, 3000 A, 2000 A, 1000 A, 900 A, 800 A, 700 A, 600 A, 500 A, 400 A, 300 A, 200 A, 100 A, 90 A, 80 A, 70 A, 60 A, 50 A, 40 A, 30 A, 20 A, 10 A or less. The duration of the application of the current may range from about 0.01 seconds (s) to about 1 s. The duration of the application of the current may be at least about 0.01 s, 0.02 s, 0.03 s, 0.04 s, 0.05 s, 0.06 s, 0.07 s, 0.08 s, 0.09 s, 0.1 s, 0.2 s, 0.3 s, 0.4 s, 0.5 s, 0.6 s, 0.7 s, 0.8 s, 0.9 s, 1 s or more. The duration of the application of the current may be less than or equal about 1 s, 0.9 s, 0.8 s, 0.7 s, 0.6 s, 0.5 s, 0.4 s, 0.3 s, 0.2 s, 0.1 s, 0.09 s, 0.08 s, 0.07 s, 0.06 s, 0.05 s, 0.04 s, 0.03 s, 0.02 s, 0.01 s or less.

[0096] The material for the support may be selected for good electrical conductivity and compatibility with the feedstock that is being deposited as segments. The material for the support may have a higher electrical conductivity than the feedstock.
Alternatively or in addition to, the material for the support may have substantially the same or a lower electrical conductivity than the feedstock. The support may be non-consumable and thus may not require replacement during normal operation. Alternatively or in addition to, the support may be replaced after printing one or more 3D objects. The support may be chosen to allow weak adhesion of the deposited segments to it, so that a first layer of deposited segments may hold the at least the portion of the 3D object firmly in place on the support during further deposition. The material for the support may have a higher electrical conductivity than the feedstock.
The material for the support may not alloy with the feedstock. The material for the support may have a higher thermal conductivity than the feedstock, such that heat generated at an area of the feedstock deposition may be quickly conducted away. For example, if the deposited metal is steel, copper or aluminum may be appropriate materials for the support. Alternatively or in addition to, the material for the support may have substantially the same or lower thermal conductivity than the feedstock to maintain the heat generated at the area of the feedstock deposition.

[0097] The application of electric current may be controlled to influence the deposition of segments (e.g., size, shape, etc.). An open-loop control of the electric current may be enabled via choosing a desired intensity level and/or duration of power prior to the deposition of segments. The desired intensity level and/or duration of power may be assigned on the power source or the controller operatively coupled to the power source. The desired intensity level of the power may be calibrated to achieve a specific voltage or current at a constant contact resistance between the feedstock and the support. Alternatively or in addition to, a closed-loop control may be used. The closed-loop control may comprise a force sensor or an electrical measurement meter (e.g., a voltmeter, ammeter, potentiometer, etc.) electrically coupled to the guide of the print head, the feedstock, the support, the power source, and/or the controller operatively coupled to the power source. In the closed-loop control, voltage and current to the tip of the feedstock may be measured in situ during deposition of the segments, and the contact resistance between the feedstock and the support may be calculated according to Equation 2 (i.e., Ohm's Law):
V
R = ¨1 (Equation 2) where V is the voltage, 1 is the electric current, and R is the contact resistance between the feedstock and the support.
The closed-loop control may beneficially eliminate failed parts due to incomplete fusion of segments and minimize heat input into the structure during deposition.

[0098] Because the contact resistance is calculated dynamically, the power of the applied electric current may be precisely controlled, thus resulting in an exact amount of heat being applied during deposition of a segment from the feedstock. The power source may supply an alternating current (AC) or a direct current (DC) to the feedstock and/or the support under an applied voltage. The applied voltage may range from about 1 millivolt (mV) to about 100 volt (V). The voltage may be at least about 1 mV, 2 mV, 3 mV, 4 mV, 5 mV, 6 mV, 7 mV, 8 mV, 9 mV, 10 mV, 20 mV, 30 mV, 40 mV, 50 mV, 60 mV, 70 mV, 80 mV, 90 mV, 100 mV, 200 mV, 300 mV, 400 mV, 500 mV, 600 mV, 700 mV, 800 mV, 900 mV, 1 V, 2 V, 3 V, 4 V, 5 V, 6 V, 7 V, 8 V, 9 V, 10 V, 20 V, 30 V, 40 V, 50 V, 60 V, 70 V, 80 V, 90 V, 100 V, or more. The applied voltage may be less than or equal about 100 V, 90 V, 80 V, 70 V, 60 V, 50 V, 40 V, 30 V, 20 V, 10 V, 9 V, 8 V, 7 V, 6 V, 5 V, 4 V, 3 V, 2 V, 1 V, 900 mV, 800 mV, 700 mV, 600 mV, 500 mV, 400 mV, 300 mV, 200 mV, 100 mV, 90 mV, 80 mV, 70 mV, 60 mV, 50 mV, 40 mV, 30 mV, 20 mV, 10 mV, 9 mV, 8 mV, 7 mV, 6 mV, 5 mV, 4 mV, 3 mV, 2 mV, 1 mV or less.

[0099] In some examples, one pole of the power source is attached to the feedstock (e.g., through a guide of the print head) and another pole of the power source is attached to the support.

[00100] The controller, the preload roller, the rotational actuator coupled to the preload roller, and the force sensor, current sensor and/or the rotary sensor of the rotational actuator may form a real-time closed-loop feedback system to control the force exerted on the feedstock. The real-time closed-loop feedback system may allow automated use of a wide range of feedstock dimensions and feedstock materials. The real-time closed-loop feedback system may allow: (1) control of power or motion system (2) control of wire feeding speed (3) dynamic compatibility with feedstocks of varying cross-sectional dimensions; (4) dynamic compatibility with feedstocks of varying materials and/or stiffness; (5) dynamic measurement of the feedstock cross-sectional dimension; (6) prevention or reduction of feedstock slippage from the gap; and (7) increasing life span of the rollers. For example, the measured reaction force may adjust the master or slave feeding system control, e.g. wire feed speed. The speed adjustment and control may be in real-time and may be continuous. The real-time closed-loop feedback system may prevent at least some of print failures due to failed feedstock feeding to improve print quality.
Additionally, the force sensor may predict and prevent sparks, which significantly reduce to print quality.

[00101] The system may comprise an optical sensor to measure the diameter of at least a portion of the feedstock before the at least the portion of the feedstock is fed through the assembly comprising the preload roller, the driver roller, and the gap adjusting mechanism that adjusts the size of the gap between the two rollers. The optical sensor may be configured between the assembly and the feedstock source. The optical sensor and the assembly may be operatively coupled to the controller. In an example, the optical sensor may be a camera that captures an image of the at least the portion of the feedstock and calculates the approximate diameter of the at least the portion of the feedstock. According to the calculated diameter of the at least the portion of the feedstock, the controller may direct the gap adjusting mechanism to adjust the gap between the two rollers, thereby maintaining the forces exerted on the feedstock approximately constant.

[00102] In some cases, the preload roller may comprise a rotary sensor (e.g., a resolver, encoder, etc.) that is operatively coupled to the controller. Examples of the encoder include an optical encoder and a rotary encoder. The encoder may be an auxiliary encoder.
The rotary sensor of the preload roller may provide position and/or speed feedback. In some cases, the controller may use the rotary sensor to track rotation of preload roller and determine a length of the feedstock that is fed through the gap between the preload roller and the driver roller. In some cases, the controller may detect when the preload roller rapidly stops rotating, which may indicate slippage of the feedstock away from the gap.

[00103] In some cases, the preload roller may comprise a force sensor to measure a contact force between the preload roller and the feedstock. The outer shell of the preload roller may comprise an encoder disc that is responsive to an exerted pressure, and the inner shell of the preload roller may comprise an encoder sensor that can measure and record the response of the encoder disc to the exerted pressure. For example, the outer shell of the preload roller may comprise a piezoelectric disc that generates piezoelectricity in response to an applied pressure by the feedstock. The inner shell of the preload roller may comprise an encoder sensor that can measure and record the change in the piezoelectricity of the preload roller while the feedstock is fed through the assembly towards or away from the guide. A sudden drastic drop in the piezoelectricity may indicate a slippage of the feedstock from the gap between the preload roller and the driver roller.

[00104] Other characteristics analyzed may comprise one or more elements selected from the group consisting of travel direction, voltage, characteristic profiles with changing feed rates for X, Y, and Z travel, feeding and retraction of the wire, power loss during print, comparison of WFS data to other sensor data, impulse response, step response of at least a portion of the 3D
print, layer-layer characteristics during print, hot and cold ends of the part, lifting pen, layer layer patterns, parallel offsets, middle offsets, arbitrary offsets, perpendicular patterns, arbitrary patterns. The parameter may be the total mass of the wire feeder and rigidity and damping changes to its mounting.

[00105] FIG. 19 schematically illustrates an example of wire feeding method ("method") 1901. This method may be used with other methods of the present disclosure. In operation 1910, the method 1901 comprises activating a 3D printing system. The 3D printing system may comprise one or more components of the system for printing the 3D object, as provided herein.
In an example, the 3D printing system has one or more components of the sensor assembly 200, as illustrated in FIG. 2.

[00106] With continued reference to FIG. 19, in operation 1920, a wire (e.g., a feedstock) is supplied through a groove in a roller (e.g., a driver roller) of the 3D
printing system. Next, in operation 1930, one or more parameters of the wire (or associated with the wire) associated with passage of the wire through a guide towards a support of the 3D printing system may be adjusted. In operation 1940, a force (e.g., a reaction force) exerted on the wire by the support may be measured. Next, in operation 1950, a measured force (or a plurality of measured forces at one position on the wire in contact with the support) may be compared to a threshold, and a determination is made as to whether the force is below the threshold.

[00107] The threshold may be a pre-determined threshold value or range of the force. The threshold may be a force acceptable by the wire without experiencing significant damage (e.g., deformation or cut). The threshold may be a force acceptable by the support without experiencing a significant damage (e.g., deformation or cut). The threshold may be specific for a type of material the wire is made of Alternatively or in addition to, the threshold may be a common threshold for different types of materials that different wires are made of.

[00108] In operation 1950, when the measured force exerted on the wire is above the threshold ("NO"), the method 1901 may comprise adjusting, in operation 1930, the one or more parameters (e.g., wire feed speed, distance between wire tip and previously printed portion of the 3D object) of the wire (or associated with the wire) associated with passage of the wire through the guide towards the support, such that the force exerted on the wire is decreased.
Alternatively, in operation 1950, when the measured force exerted on the wire is equal to or below the threshold ("YES"), the method 1901 may comprise using, in operation 1960, an actuator (e.g., an actuator coupled to the driver roller) to direct the wire through the groove and towards the guide. The guide may be part of a print head of the 3D printing system. In operation 1970, the method 1901 may further comprise supplying electrical current from the guide through the wire and to the support (or vice versa), under conditions sufficient to melt the wire when the wire is in contact with the support or a portion of a 3D object.

[00109] In another aspect, the present disclosure provides a method for printing a three-dimensional (3D) object adjacent to a support (e.g., base), comprising receiving in computer memory a computational representation of the 3D object, and using a print head to initiate printing of the 3D object by, (i) directing at least one feedstock through a feeder towards the support and (ii) flowing electrical current through the at least one feedstock and into the support, or vice versa. Next, the at least one feedstock may be subjected to heating upon flow of electrical current through the at least one feedstock and into the support, or vice versa, which heating is sufficient to melt at least a portion of the at least one feedstock. At least one layer of the at least the portion of the at least one feedstock, or the at least the portion of the at least one feedstock, may be deposited adjacent to the support in accordance with the computational representation of the 3D object, thereby printing the 3D object.

[00110] A
relative position of at least one end of the at least one feedstock (e.g., a tip of a wire) may be changed with respect to the at least one layer. A size of the at least the portion of the at least one feedstock may be controllable relative to the feedstock during deposition.

[00111] The method may further comprise repeating the deposition of at least one layer of the at least the portion of the at least one feedstock, or the at least the portion of the at least one feedstock, one or more times to deposit and shape additional portion(s) of the at least one feedstock or at least one other feedstock adjacent to the support.
Force Analysis

[00112] The back-force at the wire may be measured by isolating the force of friction coming through the sheath (F3-2) from the force that the feed hob imposes on the wire (F2-1). The force that the gantry imparts on the print head may not be measured. A subset of the equations in tables 1 and 2 may be analyzed and manipulated to assess adaptability of such measurements.
The equations may be manipulated on the left, so that the position of each variable is consistent.
On the right, a factor applied to each equation is presented. This factor may be derived empirically. The algebra can be preserved here, as one true equation may be added to another true equation any number of times.
Table 1 Equation Note Sum of forces on the wire (in Fiz = F4_1 + F2_1 + F3_1z = 0 the Z direction) Sum of forces on the wire (in Fix = F3-1X + F5-1 =
the X direction) F1A = F4-1 + F2-1 + F3-1Z +F3_1X + F5-1 +
W1 = 0 Sum of axial wire forces Sum of forces on the extruder F2 = F6_2 ¨ F2_1 + F3_2 + W2 = 0 (Z direction) Sum of forces on the sheath F3Z = ¨F3-1Z ¨ F3-2 + W3 =
(in the Z direction) Sum of forces on the sheath F3X = ¨F3-1X + F7-3 =
(in the X direction) F3A = ¨F3_2 ¨ F3_1z ¨ F3_1x ¨ F7_3 ¨ W3 = 0 Sum of axial sheath forces Table 2 Value Status F4-1 Unknown, Backforce (value of interest) F3-1X Unknown, force of the sheath on the wire (horizontal) F3-1Z Unknown, force of the sheath on the wire (vertical) F5-1 Unknown, force the spool applies to the wire F7_3 Unknown, force of ground on the sheath F2-1 Known if measured, force the hob applies to the wire F6-2 Known if measured, force of gantry on extruder.
F3_2 Known if measured, force of the sheath on the extruder.
Known if assumed constant, weight of the wire W2 Known if assumed constant, weight of the extruder.
W3 Known if assumed constant, weight of the sheath.
Table 3 Equation Factor F2_1 + 0 + F3_iz + F4_1 + 0 + 0 + 0 + 0 = ¨W1 2 0 + F3_ix+0+0+Fs_i+0+0+0=0 1 F2_1 + F3_ix + F3_iz + F4_1 + F5_1 + 0 + 0 + 0 = ¨W1 -1 0 + 0 ¨ F3_iz + 0 + 0 ¨ F3_2 + 0 + 0 = ¨W3 2 0 ¨ F3_ix+0+0+0+0+0+F7_3=0 1 0 ¨ F3_1x ¨ F3_iz + 0 + 0 ¨ F3_2 + 0 + F7_3 += ¨W3 -1

[00113] The equations in table 3, once multiplied by their respective factors, can be expressed as the dot product of two matrices equated to one another. Once the equations are expressed in a matrix as in equation 3, the columns can be summed to create another equation.
This process may be a quicker way of adding these equations or merging them by substitution. The factors applied to each equation can be modified until an equation is in the correct terms. In this example, the force between the wire and the part ( F4-1 ) can be deduced if the force applied by the hob to the wire (F2-1) is measured and the force applied by the sheath to the extruder ( F3-2) is measured.

01 0 0 1 0 0 0 F3 ix 0 0 -2 0 0 -2 0 0 = F4 1 =-2W3 0 1 1 001 0-1 F3 2, flir3 (Equation 3)

[00114] The factors may be manipulated until there is one value in the 1st, 4th, 6th column, the relationships of interest is between F2-1, F4-1, and F3-2. This demonstrates that the force between the wire and the part can be the force that the hob imparts on the wire, minus the force that the sheath imparts on the extruder, plus the unsupported weight of the wire and the unsupported weight of the sheath.
1 0 0 1 0 - 1 0 0 = [Forces] = ¨W1 ¨W3 (Equation 4) F2-1 + F4-1 ¨ F3-2 = ¨W1 ¨ W3 (Equation 5) F4-1 = ¨F2_1 + F3_2 ¨ W1 ¨ W3 (Equation 6)

[00115] In some cases, the back-force on the wire may be determined by measuring the force that the gantry applies to the print head (F6-2) and taring a weight of one or more printing components. The one or more printing components may be selected from the group consisting of sensor, frame system, mount plate, drive motor, driver roller, preload motor, and preload roller.
The equations as mentioned above may be adjusted to as verification of this measurement. For example, the equations may be manipulated on the left, so that the position of each variable remains consistent. On the right of the tables, a factor applied to each equation is shown. This factor may be derived empirically.

Table 4 Equation Factor F2_1 + 0 + F3_iz + F4_1 + 0 + 0 + 0 + 0 = ¨V171 1 0+F3_1x+0+0+F5_1+0+0+0=0 -1 F2-1 + F3-1X + F3-1Z + F4-1 + F5_1 + 0 + 0 + 0 = ¨W1 1 ¨F2_1 + 0 + 0 + 0 + 0 + F3_2 + F6_2 + 0 = ¨W2 2 0¨F3_ix+0+0+0+0+0+F7_3 =0 -1 1001161 The equations above, once multiplied by their respective factors, can be expressed as the dot product of two matrices equated to another. Once the equations are expressed in a matrix in equation 7, the columns may be summed to create another equation.
The factors applied to each may be modified until an equation is in the correct terms. In this case, the force between the wire and the part (F4-1) may be deduced if the force applied from the gantry to the extruder (F6-2) is measured and weights of system components are determined.

¨ 2: 1 1 0-1 0 0-1 0 0 0 F3 I X' 0 1 1 1 1 1 0 0 0 F3 1Z ¨1 -2 0 0 0 0 2 2 0 F4 1 = -2W2 0 -1 -1 0 0 -1 0 1 F ¨

(Equation 7) [00117] The factors may be manipulated until there is a value in the 4th and 7th column, as the relationship between F4-1 and F6-2 are of interest.
0 0 0 2 0 0 2 0 = [Forces] = ¨2W1 ¨ 2W2 ¨ 2W3 (Equation 8) 2(F4_1 + F6_2) = ¨2(W1 + W2 + W3) (Equation 9) F4-1 = -(F6-2 + W1 + W2 + W3) (Equation 10) [00118] The force between the wire and the part may be the force that the gantry imparts on the extruder, minus the weight of the extruder, the unsupported weight of the wire and the sheath.
Wire Force Sensing Modeling [00119] The performance of a system may be characterized and the load on the sensors and/or feedstock, e.g. wire, may be measured in isolation from the motors and rollers. The wire force sensing modeling can determine whether decreasing the sensor weight may result in improved performance on the sensors. In some cases, the modeling can estimate performance of the sensors so that sensor performance is not compromised with additional weight.
[00120] The WFS system may be modeled as a linear time invariant (LTI) -lumped parameter system. Using standard ordinary differential equations (ODEs), and their solutions, the WFS may be analyzed and then optimized using the mass (m), spring constant (k), and damping ratio (b). The optimized values form and b may be m = 0.3 kg and b =182 (N*s)/m. The WFS
may be sensitive enough to distinguish the difference between different quality of prints.
[00121] The mechanical, electrical, thermal, or fluidic systems may be analyzed by creating an LTI lumped parameter system. In the case of the WFS system, it can be represented accurately by an underdamped, second order mass-spring-damper model (m ¨ k ¨ b model). The spring constant may be calculated using the strain gauge specification sheets and the mounting brackets. The damping constant may be tuned to match the exponential decay of the test data.
The mass of the system can be directly measured. FIG. 3 shows a representation of the m ¨ k ¨ b model 300 used for analysis. The representation is a mass (m) 305, spring (k) 310, damper (b) 315 lumped parameter model, with a force input and direction 320.
[00122] In one example, the mass of the wire feeder was measured to be 0.47kg.
The spring constant (kT) is a composite spring comprising three strain gauge springs (ksGeg =3 *ksG) in a series with the mounting bracket (km). Equation 11 shows the formula for the total spring constant kT, which may be a function of the strain gauge and mounting bracket constants.
ksGeg *km kT = (Equation 11) (ksGeq+km) [00123] Conducting a force balance generates the ODE for the m ¨ k ¨ b model.
Equations 12 and 13 show the solution to this ODE for the underdamped case, in regular and polar form respectively.
x(t) = * 1 ¨ e't * (cos(cod * t) + * sin(cod * t)) (Equation 12) kT &id x(t) = * (1 * e't * sin (co d * t + a tan (=))) (Equation 13) kT COcl [00124] The damping ratio (b) and mounting spring constant (km) may be tuned to match the response of testing data. The WFS may be tested under a variety of conditions to generate the characteristic second order response. The exponential decay constant, and the frequency of oscillation from the data can be used to set b and km. After the model is tuned, the sensed force, e.g. the strain gauge force, can be calculated in response to a step input.
FIG. 4 shows an example step response of the strain gauge force reading, which matches experimental data.
[00125] The response time ttpeak, land settling time @settle) may be calculated as a function of (t peak) the damped natural frequency and the exponential decay rate, respectively.
Equations 14 and 15 show these formulas, which can be used to optimize this response.
n.
tpeak:= ¨wc1= 0.01S (Equation 14) ¨1 tsettle := 7 * ln(0.02) = 0.317 s(E quation 15) [00126] Once the model is representative of the data collected during testing, the m, k, and b parameters can be tuned to optimize the response. In this case, tpeak __. ic adequate (less than ¨0.015 _ s), but the tsettle is more than ten times the target of 0.02 s. The tsettle may be reduced without increasing t significantly. This can be analyzed using a graph of t _peak _peak and tsettle as a function of b, for various m. The spring constant, k, is not in question because tsettle, is not a function of k.
FIG. 5 shows the graph used for such optimization, and FIG. 6 shows a theorized optimized step response. In FIG. 5, tsettle is represented by dotted lines and tpeak __. ic represented by solid lines as a _ function of b, for m=0.2 kg, 0.3 kg, 0.4 kg, and 0.47 kg. The intersection points between the dotted line and solid line represents the optimal response. For example, when m is 0.3kg, the intersection is t = 0.013 (<0.015). The optimal values are m=0.3 kg and b=182 (N*s)/m. FIG. 6 illustrates the optimized step response of sensed force for a step input of 10 N and tpeak and t settte = 0.013 seconds.
Computer systems [00127] FIG. 7 shows a computer system 701 that is programmed or otherwise configured to communicate with and regulate various aspects of a 3D printer of the present disclosure. The computer system 701 can communicate with a power source, one or more actuators, or one or more sensors of the 3D printer. The computer system 701 can direct the power source to supply electrical current to a feedstock for use in printing a 3D object. The computer system 701 may also be programmed to communicate with one or more feedstock feeding assemblies. Each feedstock feeding assembly may comprise a driver roller, preload roller, and one or more sensors and the computer system 701 can be programmed to communicate with the driver roller, preload roller, and sensors independently or simultaneously. The computer system 701 can accelerate, decelerate, maintain at a given speed of a plurality of rotating speeds, or control the amount of power applied to the wire feeding assembly. The computer system 701 can be programmed to use the sensors to measure a reaction force of the wire.
[00128] The computer system 701 can be an electronic device of a user or a computer system that is remotely located with respect to the electronic device. The electronic device can be a mobile electronic device.
[00129] The computer system 701 includes a central processing unit (CPU, also "processor"
and "computer processor" herein) 705, which can be a single core or multi core processor, or a plurality of processors for parallel processing. The computer system 701 also includes memory or memory location 710 (e.g., random-access memory, read-only memory, flash memory), electronic storage unit 715 (e.g., hard disk), communication interface 720 (e.g., network adapter) for communicating with one or more other systems, and peripheral devices 725, such as cache, other memory, data storage and/or electronic display adapters. The memory 710, storage unit 715, interface 720 and peripheral devices 725 are in communication with the CPU 705 through a communication bus (solid lines), such as a motherboard. The storage unit 715 can be a data storage unit (or data repository) for storing data. The computer system 701 can be operatively coupled to a computer network ("network") 730 with the aid of the communication interface 720. The network 730 can be the Internet, an internet and/or extranet, or an intranet and/or extranet that is in communication with the Internet. The network 730 in some cases is a telecommunication and/or data network. The network 730 can include one or more computer servers, which can enable distributed computing, such as cloud computing. The network 730, in some cases with the aid of the computer system 701, can implement a peer-to-peer network, which may enable devices coupled to the computer system 701 to behave as a client or a server.
[00130] The CPU 705 can execute a sequence of machine-readable instructions, which can be embodied in a program or software. The instructions may be stored in a memory location, such as the memory 710. The instructions can be directed to the CPU 705, which can subsequently program or otherwise configure the CPU 705 to implement methods of the present disclosure.
Examples of operations performed by the CPU 705 can include fetch, decode, execute, and writeback.
[00131] The CPU 705 can be part of a circuit, such as an integrated circuit.
One or more other components of the system 701 can be included in the circuit. In some cases, the circuit is an application specific integrated circuit (ASIC).
[00132] The storage unit 715 can store files, such as drivers, libraries and saved programs.
The storage unit 715 can store user data, e.g., user preferences and user programs. The computer system 701 in some cases can include one or more additional data storage units that are external to the computer system 701, such as located on a remote server that is in communication with the computer system 701 through an intranet or the Internet.
[00133] The computer system 701 can communicate with one or more remote computer systems through the network 730. For instance, the computer system 701 can communicate with a remote computer system of a user. Examples of remote computer systems include personal computers (PC) (e.g., portable PC), slate or tablet PC's (e.g., Apple iPad, Samsung Galaxy Tab), telephones, Smart phones (e.g., Apple iPhone, Android-enabled device, Blackberry ), or personal digital assistants. The user can access the computer system 701 via the network 730.
[00134] Methods as described herein can be implemented by way of machine (e.g., computer processor) executable code stored on an electronic storage location of the computer system 501, such as, for example, on the memory 710 or electronic storage unit 715. The machine executable or machine readable code can be provided in the form of software. During use, the code can be executed by the processor 705. In some cases, the code can be retrieved from the storage unit 715 and stored on the memory 710 for ready access by the processor 705. In some situations, the electronic storage unit 715 can be precluded, and machine-executable instructions are stored on memory 710.
[00135] The code can be pre-compiled and configured for use with a machine having a processer adapted to execute the code, or can be compiled during runtime. The code can be supplied in a programming language that can be selected to enable the code to execute in a pre-compiled or as-compiled fashion.

[00136] Aspects of the systems and methods provided herein, such as the computer system 501, can be embodied in programming. Various aspects of the technology may be thought of as "products" or "articles of manufacture" typically in the form of machine (or processor) executable code and/or associated data that is carried on or embodied in a type of machine readable medium. Machine-executable code can be stored on an electronic storage unit, such as memory (e.g., read-only memory, random-access memory, flash memory) or a hard disk.
"Storage" type media can include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. All or portions of the software may at times be communicated through the Internet or various other telecommunication networks. Such communications, for example, may enable loading of the software from one computer or processor into another, for example, from a management server or host computer into the computer platform of an application server. Thus, another type of media that may bear the software elements includes optical, electrical and electromagnetic waves, such as used across physical interfaces between local devices, through wired and optical landline networks and over various air-links. The physical elements that carry such waves, such as wired or wireless links, optical links or the like, also may be considered as media bearing the software. As used herein, unless restricted to non-transitory, tangible "storage" media, terms such as computer or machine "readable medium" refer to any medium that participates in providing instructions to a processor for execution.
[00137] Hence, a machine readable medium, such as computer-executable code, may take many forms, including but not limited to, a tangible storage medium, a carrier wave medium or physical transmission medium. Non-volatile storage media include, for example, optical or magnetic disks, such as any of the storage devices in any computer(s) or the like, such as may be used to implement the databases, etc. shown in the drawings. Volatile storage media include dynamic memory, such as main memory of such a computer platform. Tangible transmission media include coaxial cables; copper wire and fiber optics, including the wires that comprise a bus within a computer system. Carrier-wave transmission media may take the form of electric or electromagnetic signals, or acoustic or light waves such as those generated during radio frequency (RF) and infrared (IR) data communications. Common forms of computer-readable media therefore include for example: a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or digital versatile disk - read only memory (DVD-ROM), any other optical medium, punch cards paper tape, any other physical storage medium with patterns of holes, a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM) and erasable programmable read-only memory (EPROM), a FLASH-EPROM, any other memory chip or cartridge, a carrier wave transporting data or instructions, cables or links transporting such a carrier wave, or any other medium from which a computer may read programming code and/or data. Many of these forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to a processor for execution.
[00138] The computer system 701 can include or be in communication with an electronic display 735 that comprises a user interface (UI) 740 for providing, for example, (i) activate or deactivate a 3D printer for printing a 3D object, (ii) determine a reaction force exerted by the support against the at least one wire, or (iii) determine a wire feed speed or amount of power applied to the wire feeding assembly. Examples of UI' s include, without limitation, a graphical user interface (GUI) and web-based user interface.
[00139] Methods and systems of the present disclosure can be implemented by way of one or more algorithms. An algorithm can be implemented by way of software upon execution by the central processing unit 705. The algorithm can, for example, (i) determine a reaction force exerted by the support against the at least one wire, or (ii) dynamically change the wire feed speed or amount of power applied to the wire feeding assembly for printing a 3D object.
EXAMPLES
[00140] The examples below are illustrative and non-limiting Example 1 [00141] Prior to printing the 3D object, a calibration procedure may be used by suspending a known weight from a piece of fed wire. The calibration of the WFS
can be performed as a system, instead of individually for each strain gauge. The system may self calibrate. The calibration range may be in the compression state of the strain gauges, while the primary forces exerted by the wire back force may be in the tension regime of the strain gauges.
First, it may be determined whether calibrating each strain gauge separately is required, or if the WFS may be calibrated as a system. FIG. 8 shows three sensors' individual readings in volts and the sum (bottom most curve) of the three sensors for a series of loads. This test may be performed on a test fixture. Based on this test, the simplified calibration procedure of adding the sensor readings of each strain gauge may be used, allowing for work with one output (summed voltage) that may result in less noise than the individual sensor readings.
This may be due to the averaging of individual sensor noise. In some cases, using three sensors can result in less noise than using one sensor.
[00142] FIG. 9 is the second calibration of the system, a more detailed version of FIG 8.
This calibration is performed once using a WFS on the printer. Each load is measured three times and with capacity for additional loads to be used, e.g. focusing on near zero load. Additionally, more samples are used in determining the degree of variation. For tests on the test fixture, the calibration from FIG. 8 is used. For tests on the 3D printer, the calibration from FIG. 9 is used.
The strain gauges are retightened while on the 3D printer, which may have changed the intercept of the calibration. The slope of the calibration may not be altered significantly.
Example 2 [00143] FIG. 10 shows the system response while the feeder motor is powered but stationary and a hammer is used to hit the wire tip into the contact tip. The testing illustrates how quickly the system would respond and how quickly to review data and use it in the control system. From the data, the response time (plotted as peaks and troughs) of the WFS is 0.0038s.
Response time may be defined as the time to reach the first peak. The 2%
settling time of the WFS is 0.1089s. The 2% settling time limits are plotted as horizontal lines.
Example 3 [00144] FIG. 11 and FIG. 12 show measurements as a wire is driven through a wire feeder and illustrates the sensor noise in determining the type of sensor filtering required in a control system. FIG. 11 illustrates measurements of a friction load applied to the wire. Alternatively, in FIG. 12, the wire is freely driven. Both these tests are performed on the test fixture and the data is obtained from the WFS. The line is a 100-point moving average of the data and an effective low pass filter of the system response. The average delta from the moving average in Table 5 and Table 6 is the average of each data point minus the 100-point moving average.
The maximum value in these tables is the maximum distance a data point is from the moving average. The standard deviation is calculated over that noted stretch of the data. Based on the results shown in Table 5 and Table 6, the system noise is not affected by the load. The baseline sensor noise is around 0.12N and the current wire driver contributes 0.73N additional noise to measurements.

Table 5 Sample Time Range 5.2 to 5.7 15 to 17 Ave. Delta to Moving Average 1.432 0.158 Max 4.439 0.890 STD Dev 0.847 0.120 Table 6 Sample Time Range 3.9 to 5.9 1 to 3 Ave. Delta to Moving Average 1.202 0.167 Max 3.850 0.865 STD Dev 0.882 0.125 Example 4 [00145] FIG. 13 illustrates test data from printing a line while changing the extrusion ratio. The extrusion ratio is the starting cross-sectional area of the wire divided by the cross-sectional area of the wire after extrusion. FIG. 14 shows the result of the test print, roughly lined up with FIG. 13. For this test, the feed rate is constant and set to 4000 mm/min. Each segment of the line where a feed rate change occurred is marked by a vertical line.
Various segments are illustrated. Segment 1305 has an extrusion ratio of 1. Segment 1310 has an extrusion ratio of 1.15. Segment 1315 has an extrusion ratio of 1.3. Segment 1320 has an extrusion ratio of 1.45.
Segment 1325 has an extrusion ratio of 1.6. Segment 1330 has an extrusion ratio of 1.75.
Segment 1335 has an extrusion ratio of 0. Segment 1325 prints the smoothest (in FIG. 14), the standard deviation is 0.510 N with an average load of 0.379N. The standard deviation may be compared to recorded data from the same test where there is no motion (0.014N) and where there is noise while moving the gantry at the same speed without printing (0.822N).
The graph illustrates that a different response in data correlates to a different response in the actual print.
When noise is first observed in the printing process, the printing parameter in the control system may be adjusted. However, in some cases, various noises may result from the resultant print.

[00146] The segment of the test while moving but not printing (bottom curve) is shifted below the printing test data (top curve) for comparison. The top curve has a clear pattern with multiple frequencies while being larger in magnitude than the bottom curve (the clean print).
Example 5 [00147] FIG. 15 illustrates a pair of tests 1520 and 1525 stacked on top of one another during printing of corner turns in portions of an object. The printer initiates printing at 1505 for 40 mm in one direction, then turns 900 at 1510 and prints another 40 mm until the print stops at 1515. Of the trials performed, none shows a definitive signal at the corner turn. The sensors may not detect a specific response from turning as this movement may not affect the axial forces. The noises in FIG. 15 may be purely a measure of print quality. As a result, when analyzing resultant noise from a print, that from a printing head changing direction may not need to be filtered from the resultant noise.
Example 6 [00148] FIG. 16 and FIG. 17 are a series of tests in which the wire is pushed with a specified feed length into a solid piece of metal. FIG. 16 shows the amount of force read by the sensors. In some cases, there may be system movement from the other printing components, e.g. load cells.
As a result, when the wire is pushed down, the system is not fully rigid. As shown in FIG. 17, the feed rate indicates that a ramp loading of the WFS occurred rather than a step load. During the 2 mm feed test, there is an audible skip. The current wire feeder slips at about 30 Newtons (N) based on this data. In other examples, the wire feeder slips a little higher at about 35N-45N.
[00149] Curve 1605 illustrates a situation in which a quantity of the wire is extruded such that that the wire pushes into the plate and the amount of force remains constant.
In curve 1610, a greater quantity of the wire is extruded and more force is detected as the wire is pushed at a higher force into the plate. Next, additional wire 1615 is extruded until the force is sufficiently high such that the wire slips in the preload system. When a peak force is observed, the wire undergoes a slipping action and subsequently settles to a lower force. FIG. 17 is an enlargement between regions 4 and 5 on the x-axis of FIG 16.
Example 7 [00150] FIG. 18 illustrates signal from the process of filling a hole when repairing a portion of the 3D object. A hole may be formed in a piece of metal and the wire may be directed toward the hole. The wire may be heated over time and may melt as it hits the bottom of the hole when current passes through the wire. When the wire initially hits the bottom at 1805, it is a cold piece of metal and a spike in the force occurs. Then, the force drops off quickly as the wire melts.
Another few millimeters of wire may be extruded and repeated at various start points 1810, 1815, and 1820. The successive peaks 1810, 1815, and 1820 are smaller than the first peak 1805 because following each deposition more molten metal develops and the metal temperature increases. Once the hole is filled, the deposition of molten wire ends as the wire is pushing against the hard metal, resulting in the largest spikes at 1825.
[00151] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is therefore contemplated that the invention shall also cover any such alternatives, modifications, variations or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

Claims

WHAT IS CLAIMED IS:

1. A method for printing at least a portion of a three-dimensional (3D) object adjacent to a support, or a deposited portion of said 3D object, comprising:
(a) directing a first portion of at least one wire toward and in contact with said support, or said deposited portion of said 3D object, in accordance with at least one parameter;
(b) upon contacting said at least one wire with said support, or said deposited portion of said 3D object, using one or more sensors to generate a signal(s) indicative of a reaction force exerted by said support, or said deposited portion of said 3D
object, against said at least one wire, to provide a measured value;
(c) adjusting said at least one parameter in response to said measured value to provide at least one adjusted parameter; and (d) bringing a second portion of said at least one wire toward and in contact with said support, or said deposited portion of said 3D object, in accordance with said at least one adjusted parameter.

2. The method of claim 1, wherein said at least one parameter is adjusted when said reaction force exceeds a threshold value.

3. The method of claim 1, further comprising subjecting said second portion of said at least one wire to heating upon flow of electrical current through said at least one wire and into said support, or said deposited portion of said 3D object, or vice versa, which heating is sufficient to melt said second portion of said at least one wire.

4. The method of claim 3, further comprising depositing said second portion of said at least one wire on said support, or said deposited portion of said 3D object, thereby forming said at least said portion of said 3D object.

5. The method of claim 1, wherein said first portion of said at least one wire is directed through a wire feeding assembly.

6. The method of claim 5, wherein said at least one parameter is selected from the group consisting of a wire feed speed, distance between a tip of said at least one wire and said support or said deposited portion of said 3D object, distance between said tip of said at least one wire and said at least said portion of said 3D object, amount of power applied to said wire feeding assembly, amount of current applied to said wire feeding assembly, and amount of voltage applied to said wire feeding assembly.

7. The method of claim 5, wherein said one or more sensors are kinematically mounted to hold said wire feeding assembly.

8. The method of claim 5, wherein said wire feeding assembly comprises a supporting wire guide and a wire feeder, wherein said supporting wire guide accepts said at least one wire from said wire feeder and directs said at least one wire towards said support, or said deposited portion of said 3D object.

9. The method of claim 8, wherein said supporting wire guide is in contact with said wire feeder.

10. The method of claim 1, wherein said one or more sensors comprise one or more strain gauges.

11. The method of claim 1, wherein prior to (a), said one or more sensors is calibrated.

12. The method of claim 1, wherein (b) comprises measuring said reaction force in isolation from an upstream tension of said at least one wire.

13. The method of claim 1, wherein said first portion of said at least one wire is directed using a print head, and wherein (b) comprises (i) determining an applied force applied by a gantry to said print head, and (ii) removing a weight of one or more printing components from said applied force to determine said reaction force.

14. The method of claim 13, wherein said one or more printing components is selected from the group consisting of sensor, frame system, mount plate, drive motor, driver roller, preload motor, and preload roller.

15. The method of claim 1, further comprising, prior to (a), selecting said at least one parameter.

16. The method of claim 1, wherein said support is a platform.

17. The method of claim 1, wherein said support is a previously deposited portion of said 3D
object.

18. The method of claim 1, wherein said support is a sacrificial object.

19. A system for printing at least a portion of a three-dimensional (3D) object adjacent to a support or a deposited portion of said 3D object, comprising:
a support configured to hold said at least said portion of said 3D object;
a source configured to hold at least one wire, which at least one wire is usable for said printing of said at least said portion of said 3D object;
one or more sensors configured to generate a signal(s) indicative of a reaction force of said support, or said deposited portion of said 3D object, against said at least one wire;

a power supply configured to flow electrical current through said at least one wire and said support, or said deposited portion of said 3D object; and a controller operatively coupled to said power supply, wherein said controller is configured to:
i. direct a first portion of said at least one wire toward and in contact with said support, or said deposited portion of said 3D object, in accordance with at least one parameter;
ii. upon contacting said at least one wire with said support, or said deposited portion of said 3D object, receive said signal(s) from said one or more sensors indicative of said reaction force exerted by said support, or said deposited portion of said 3D
object, against said first portion of said at least one wire to provide a measured value;
iii. adjust said at least one parameter in response to said measured value to provide at least one adjusted parameter; and iv. direct a second portion of said at least one wire toward and in contact with said support, or said deposited portion of said 3D object, in accordance with said at least one adjusted parameter.

20. The system of claim 19, further comprising a wire feeding assembly comprising a supporting wire guide and a wire feeder, wherein said supporting wire guide accepts said at least one wire from said wire feeder and directs said at least one wire towards said support, or said deposited portion of said 3D object.

21. The system of claim 20, wherein said one or more sensors are kinematically mounted to hold said wire feeding assembly.

22. The system of claim 20, wherein said supporting wire guide is in contact with said wire feeder.

23. The system of claim 19, wherein said one or more sensors comprise one or more strain gauges.

24. The system of claim 19, wherein said controller is configured to direct flow of electrical current through said second portion of said at least one wire and into said support or said deposited portion of said 3D object, or vice versa, to subject said second portion of said at least one wire to heating, which heating is sufficient to melt said second portion of said at least one wire.

25. The system of claim 24, wherein said controller is configured to direct said second portion of said at least one wire to be deposited on said support or said deposited portion of said 3D object, thereby forming said at least said portion of said 3D object.

26. The system of claim 19, wherein said controller is configured to measure said reaction force of said at least one wire in isolation of an upstream tension of said at least one wire.

27. The system of claim 19, wherein said controller is configured to adjust said at least one parameter when said reaction force exceeds a threshold value.

28. The system of claim 19, wherein said support is a platform.

29. The system of claim 19, wherein said support is a previously deposited portion of said 3D
object.

30. The system of claim 19, wherein said support is a sacrificial object.