Abstract: The invention relates to a device and method for increasing the speed and increasing the stability of the welding pin in friction stir welding with the following device features: a) a tool drive has a retaining flange for a cone-shaped tool cover with a union nut; b) an annular retaining ring surrounds a pin shank with a tool shoe secured to the diameter of the retaining ring, wherein the tool shoe has a smoothing and compressing surface in the region of the pin tip for smoothing the weld seam, wherein the pin shank has the width of the tool shoe; c) the pin tip has an annular friction surface which surrounds a screw conveyor for the output of material transport from the pin tip, which has a thread running in the opposite direction to the thread of the pin tip.

Abstract: A friction stir additive manufacturing device configured to join a first work-piece and a second work-piece is provided. In one aspect, the device includes a rotating spindle configured to deposit a filler material over a weld line as the device is advanced along an interface between the first work-piece and the second work-piece. The device also includes a deposition head configured to receive at least a portion of the spindle, the deposition head configured to remain stationary relative to the rotating spindle. The deposition head includes a first semi-cylindrical portion having an inner radius and an outer radius relative to a first axis, and a second semi-cylindrical portion having an inner radius and an outer radius relative to a second axis that is perpendicular to the first axis. The second semi-cylindrical portion can include a chamfered inner surface configured to define a weld profile.

Abstract: This disclosure relates to a friction stir welding tool insert comprising a polycrystalline cubic boron nitride, PCBN, composite material with a textured surface layer. The textured surface layer comprises a pre-defined repeating pattern.

Abstract: This disclosure relates to a two-piece friction stir welding (FSW) tool insert. The tool insert has a longitudinal axis of rotation and comprises a stirring pin and an annular shoulder coaxially mounted about the stirring pin. The stirring pin and annular shoulder each comprise polycrystalline cubic boron nitride. The annular shoulder is a thin disc with a thickness of 1 to 12 mm and the shoulder comprises a tapered, central aperture, through which the stirring pin protrudes.

Abstract: A friction stir welding tool for a machine tool having a frame and a spindle rotatable relative to the frame. The friction stir welding tool includes a pin, a shoulder, and a drive shaft connectable to the spindle to set the pin and shoulder in rotational motion about a rotation axis, wherein the shoulder is rotatable relative to the pin about the rotation axis. To obtain different speeds of the pin and shoulder in a simple and robust manner, a planetary transmission having a ring gear, a planet carrier, and a sun gear is connected to the drive shaft, pin, and shoulder. The pin or the shoulder is connected to the planet carrier so that the pin and shoulder are set in rotation about the rotation axis at different rotational speeds, but in the same rotation direction, by driving the drive shaft by the spindle.

Abstract: A friction stir spot welding apparatus includes a pin member formed in a solid cylindrical shape, a shoulder member formed in a hollow cylindrical shape, the pin member being inserted in the shoulder member, a rotary actuator that rotates the pin member and the shoulder member on an axis that is in agreement with an axial center of the pin member, and a linear actuator that linearly moves each of the pin member and the shoulder member along the axis. A tip-end part of the shoulder member is formed in a tapered shape.

Abstract: Disclosed are rotating tools for double-sided friction stir welding that are applied to double-sided friction stir welding, which is a technique for welding two metal plates by rotating a pair of rotating tools, which oppose each other, in opposite directions, a double-sided friction stir welding apparatus that uses the rotating tools, and a double-sided friction stir welding method. A pair of rotating tools for double-sided friction stir welding that are used in double-sided friction stir welding, which is a technique for welding metal plates by using a pair of rotating tools that are each disposed on one of first and second surfaces of an unwelded portion of the metal plates such that the rotating tools rotate in opposite directions, include end portions each of which is formed in a circular and planar shape. The end portions are each made of a material harder than the metal plates.

Abstract: A method of forming a rod feedstock for titanium stir friction welding additive manufacturing may comprise: mixing a plurality of powdered metals comprising titanium, iron, vanadium, and aluminum to produce a powder blend; at least one of die pressing the powder blend to form a die pressed powder or continuously powder rolling the powder blend to form a die pressed powder; and sintering the powder blend to form a rod feedstock having a cross-sectional profile.

Abstract: The invention relates to a work interface accessory, comprising an external body having a wall delimiting a recess for the introduction of a rotating portion of the friction stir welding head, an upper plate comprising fastening portions against the head, a central rotating shaft projecting to carry a work tool, the shaft comprising an internally toothed coupling sleeve to allow the shaft to be driven in rotation, when an externally toothed ring gear of the rotating portion of the head rotates in the sleeve.

Abstract: A friction stir joining device includes a tool, a rotary driver, a linear-movement driver, and a control device. The control device is adapted to (A) dispose so that a first member opposes to the tool, and the first member, a second member and a third member are located in this order, (B) control the linear-movement driver and the rotary driver so that a tip-end part of the tool presses a joined part of a to-be-joined object while the tool is rotated, (C) control the linear-movement driver and the rotary driver so that the third member softened extends above an upper surface of the second member, and the tip-end part of the tool reaches a first position, and (D) control the linear-movement driver and the rotary driver so that the tool is drawn out from the joined part while the tool is rotated.

Abstract: A friction stir welding tool holder is provided and includes: a tool holder cone, an end thereof is connected to the rotating spindle, a cone flow channel is formed therein, the cone flow channel has a valve, and the tool holder cone further has a tool locking ring, and the tool locking further has a tool accommodation groove axially arranged and a thermal sensing slot laterally arranged; a cutting tool, axially movable relative to the tool holder cone, where the cutting tool is arranged in the tool accommodation groove and has a machining end protruding from the tool accommodation groove; a torque transmission system, arranged between the tool holder cone and the cutting tool to transmit torque from the tool holder cone to the cutting tool; and a thermal sensor, inserted in the thermal sensing slot to sense a temperature of the cutting tool at any time.

Abstract: Methods, systems, and apparatuses for component manufacturing are provided. A component may be manufactured via an extrusion of loose substrate material into a unitary tubing. Features may be added to the tubing via friction stir additive manufacturing to manufacture a component. In this manner, a component may be manufactured from titanium alloys while processing challenges such as iron segregation or material loss through machining are ameliorated. Such a component may replace steel or other high strength components and further exhibits corrosion resistance.

Abstract: In a method of applying a weld to a target surface, a guide rail arrangement is attached to the target, the guide rail arrangement including at least one guide rail. A weld head carriage having a carriage housing, a rail follower assembly, and a sonotrode is movably mounted to the guide rail arrangement so that the follower assembly engages each guide rail for movement there-along. The weld head carriage is positioned adjacent the target surface, feedstock material is deposited onto the target surface, and the sonotrode is extended to engage the deposited feedstock material and apply a welding force to the feedstock material and the target. Relative movement between the carriage and the guide rail arrangement is initiated and ultrasonic vibrations are conducted into the feedstock material and the target, thereby welding the feedstock material to the target surface.

Abstract: In a double-acting friction stir spot welding device or a double-acting friction stir spot welding method, a pin member and a cylindrical shoulder member that rotates around the axis of the pin member are used as rotary tools, and a clamp member that has a cylindrical shape positioned so as to surround the outside of the shoulder member and is configured to press a workpiece from an obverse surface with an annular pressing surface of the distal end is used as a holding jig. The clamp member has an inclined surface that is adjacent to the inner edge portion of the pressing surface and inclined so as to reduce the inner diameter of the clamp member toward the back side as viewed from the pressing surface.

Abstract: A first plastic part is fixtured in a first fixture, and a second plastic part is fixtured in a second fixture for welding to each other. The first plastic part can be independently moved relative to the second plastic part in each of three directions: 1) linearly in a direction parallel with a z-axis, 2) linearly in a direction parallel with an x-axis, and 3) circularly in a circular arc about an axis parallel with a y-axis.

Abstract: The present invention relates to a friction stir welding head including a central pin shaft, a peripheral shoulder part, a shaft for driving in rotation the part and the shaft about the axis, the shaft being integral in rotation with the part and being free in translation with respect to the part along the axis, the head including an external interface part intended to be secured to a rotary spindle of the machine, a device for transmitting the rotation of the shaft about the axis of rotation from the part and a device for driving in translation the shaft along the axis from the motor during the rotation of the shaft and of the part.

Abstract: A method of forming an internal channel within a workpiece. In an embodiment, the method includes (a) rotating a tool about a central axis, wherein the tool includes: a shoulder; a pin extending axially from the shoulder; and a flange mounted to the pin that is spaced from the shoulder along the central axis. In addition, the method includes (b) moving the tool across the workpiece in a radial direction with respect to the central axis during (a). Further, the method includes (c) engaging the shoulder of the tool with an outer surface of the workpiece during (a) and (b), (d) submerging the pin and the flange within the workpiece during (a) and (b); and (e) forming the internal channel with the flange during (a) and (b).

Abstract: A split-type friction stir welding head with an adjustable stirring pin length includes a stirring head housing, where a clamping handle and a detachable stirring pin are successively mounted in the stirring head housing towards a welding direction, the clamping handle is provided with external threads on a periphery thereof and in drive connection with an adjusting plate through threads, the adjusting plate is limited, fixed and mounted in the stirring head housing, and a pore-diameter-adjustable aperture shoulder is mounted between a bottom of the stirring head housing and the detachable stirring pin in order to compensate for an outside gap between a stirring pin channel of the stirring head housing and the detachable stirring pin.

Abstract: A method for making a container for retaining anesthetic agent. The method includes creating two or more parts each having a mating surface, where the container is formed when the mating surfaces of the two or more parts are coupled together, and where a first part of the two or more parts is formed of a material having pores defined within the mating surface thereof. The method further includes processing the mating surface of the first part via friction stir welding to reduce the pores defined therein. The method further includes coupling the two or more parts together such that the mating surfaces contact to create the container configured to retain the anesthetic agent therein.

Abstract: A shoulder-angle-adjustable friction stir welding head suitable for a fillet joint includes a stirring head body. A front end of the stirring head body is mounted with a movable shoulder, a stirring pin channel is arranged on the movable shoulder, and the stirring pin channel may allow a stirring pin of the stirring head body to pass through. The present disclosure can respond to welding tasks of the fillet joint of different angles and enlarges an application scope of the friction stir welding head in a manner that the front end of the stirring head body is mounted with the movable shoulder, the stirring pin channel is arranged on the movable shoulder, the stirring pin channel is used for allowing the stirring pin of the stirring head body to pass through, and the angle of the movable shoulder is adjusted.

Abstract: A stir pin includes a base end portion configured to be held rotatably about a first axis, a stirring portion provided to project from a shoulder member to be rotatable about the first axis together with the base end portion, and an intermediate portion including a second portion connected to the stirring portion to be rotatable about the first axis together with the stirring portion and having a second diameter passing through the first axis, and a first portion provided between and connected to the base end portion and the second portion to be rotatable about the first axis together with the base end portion and the second portion. The first portion has an end surface to which the second portion is connected and which has a maximum diameter larger than the second diameter. The end surface has a ring-shaped receiving surface configured to receive a material waste.

Abstract: A method for joining or machining, in particular a friction stir welding method, using an apparatus, in which a tool, in particular a friction stir welding tool, is driven via a spindle with a spindle axis. To achieve high process reliability, even when the method is applied in poorly accessible positions, an adapter, in particular an angle head, is arranged between the spindle and the tool so that the tool axis about which the tool rotates does not coincide with the spindle axis. A force acting on the spindle is measured and the method is controlled depending on the force measured at the spindle. The apparatus for joining or machining, in particular for friction stir welding, includes a headstock with a spindle, which can be rotated about a spindle axis and a tool, in particular a friction stir welding tool, which can be driven about a tool axis by the spindle.

Abstract: The invention provides a retractable friction stir welding spindle, aims at the deficiencies and defects of the existing friction stir welding spindle technology, that is, when the welding is finished, the stirring needle leaves a keyhole at the end of the weld seam, which affects the forming performance of the workpiece, the overall structure design of the spindle is complicated with many transmission chains and low reliability which is difficult to realize modularization. The retractable friction stir welding spindle includes an electric spindle system and a retracting mechanism. The electric spindle system includes stirring shaft shoulder, hilt, front end cover, hollow spindle, motorized spindle shell, motor rotor, motor stator, tail end cover, etc. The retracting mechanism includes stirring needle, connecting ball head and electric cylinder. The invention has the advantages of simple structure and can be mainly divided into two modules to improve reliability and integrity.

Abstract: A method for joining dissimilar metals according to the embodiment is a method for butt-joining, using frictional heat, a first member having a plate shape and containing first metal and a second member having a plate shape and containing second metal having a melting point higher than that of the first metal. The method for joining dissimilar metals includes: overlapping an end portion of the second member on an end portion of the first member; and pressurizing the second member toward the first member by bringing a rotating joining tool having a protruding portion at a tip end into contact with an overlapping portion of the second member with the first member. When the second member is pressurized toward the first member, the tip end of the rotating joining tool is not in contact with the first member.

Abstract: A friction stir welding apparatus includes a welding tool that includes a shoulder and a probe supported by the shoulder, is inserted into a plurality of welding target members, and moves while rotating to weld the plurality of welding target members, a spindle motor that is coupled to the welding tool to rotate the welding tool in a predetermined direction, a welding head that supports the spindle motor, and an apparatus body that supports the welding head, applies a drive signal to the spindle motor, and moves the welding tool along a welding line while rotating the welding tool.

Abstract: The invention relates to a device and method for increasing the speed and increasing the stability of the welding pin in friction stir welding with the following device features: a) a tool drive (1) has a retaining flange (2) for a cone-shaped tool cover (3) with a union nut (4); b) an annular retaining ring (12) surrounds a pin shank (6) with a tool shoe (7) secured to the diameter of the retaining ring (12), wherein the tool shoe (7) has a smoothing and compressing surface (11) in the region of the pin tip (10) for smoothing the weld seam, wherein the pin shank has the width of the tool shoe (7); c) the pin tip (10) has an annular friction surface (9) which surrounds a screw conveyor (8) for the output of material transport from the pin tip (10), which has a thread running in the opposite direction to the thread of the pin tip (10).

Abstract: The present application relates to a friction stir welding tool insert comprising a polycrystalline cubic boron nitride, PCBN, composite material with a textured surface layer. The textured surface layer comprises a pre-defined repeating pattern.

Abstract: The invention makes available a tool for friction stir welding, which makes it possible, with reduced effort, to connect two panel elements that butt up against one another with one another by means of friction stir welding, in the case of which a tunnel is formed in the region of the abutting side surfaces, by means of recesses formed in the manner of a channel in the side surfaces in question.

Abstract: A method for a model-based open-loop and closed-loop control of an internal combustion engine includes the steps of: determining, via a combustion model, injection system setpoint values for controlling injection system actuators, according to a setpoint torque; adapting, during an operation of the internal combustion engine, the combustion model according to a model value, the model value being calculated from a first Gaussian process model for representing a base grid and a second Gaussian process model for representing adaptation data points; determining, by an optimizer, a minimized measure of quality by changing the injection system setpoint values within a prediction horizon, and, in an event that the minimized measure of quality is found, the injection system setpoint values are set as critical for adjusting an operating point of the internal combustion engine; and monitoring the model value in respect of a monotony which is predefined.

Abstract: A dissimilar metal welding method includes a preparing step and a working step. In the preparing step, a pin member is moved to a second metal material while being rotated, and a tool body is driven such that the tool body is moved in a direction away from the second metal material while being rotated. In the working step, a through-hole is formed in the second metal material by the pin member, and then a distal end of the pin member is dug into the first metal material to a predetermined depth position in the first metal material.

Abstract: The present invention discloses an electromagnetic pulse-aided friction stir lock welding processing device and method, which comprises an upper die body and a lower die body. The upper end of the lower die body is provided with a frustum-shaped settling tank. The lower end of the upper die body is provided with a tip inserted into the settling tank, an outer wall of the tip is fitted with an inner wall of the settling tank, a gap for placing parts to be processed is arranged between the upper die body and the lower die body.

Abstract: An object of the present invention is to provide a joining method by which metal members can be suitably joined to each other. The present invention is characterized by including a friction stirring process in which the first metal member, the second metal member, and the auxiliary member are joined to one another by moving the rotary tool along the inner corner portion in a state where the tip side pin which is being rotated is inserted into the inner corner portion, is in contact with the first metal member, the second metal member, and the auxiliary member, and an outer circumferential face of the base side pin is pressed against the auxiliary member.

Abstract: Provided are a friction stir welding apparatus and a friction stir welding method that achieve highly accurate and highly reliable joining while minimizing an effect of bending of a pressing force receiving portion (carrying table) as a result of a press by a joining tool unit. The friction stir welding apparatus joins joining target members by friction stir welding. The friction stir welding apparatus is characterized by including: an apparatus main body; a control device that controls an operation of the friction stir welding apparatus; a C-shaped frame connected to the apparatus main body via a first vertical movement drive mechanism unit; a holder unit connected to one end of the C-shaped frame via a second vertical movement drive mechanism unit; and a joining tool held by the holder unit.

Abstract: A bonding device for joining together a first member (3), an intermediate member (4), and a second member (3) which are layered as a laminated assembly includes a probe (12, 41), an anvil (11, 11b, 11c, 11d), a shoulder member (13,13a, 61,64,68), a drive mechanism (14) configured to rotate the probe around the central axial line and move the probe toward and away from the second member along the central axial line, and an electric power supply (15) electrically connected to the anvil and the shoulder member to conduct electric current through the laminated assembly via the anvil and the shoulder member.

Abstract: The present invention is characterized by including a primary joining process to perform friction stirring to a first butted portion by moving a stirring pin one round around a sealing body with a predetermined depth along a set moving route set at an inner position relative to an outer peripheral side face in a state that only the stirring pin of a rotary tool being rotated is inserted into the sealing body and that an outer face of the stirring pin is slightly in contact with a step side face of a peripheral wall step portion. In the primary joining process, after only the stirring pin being rotated is inserted into a starting position set at a position on an inner side relative to the set moving route, the stirring pin is gradually inserted to the predetermined depth while an axis of the rotary tool is moved to a position on the set moving route.

Abstract: A dissimilar metal welding method includes a preparing step and a working step. In the preparing step, a pin member is moved to a second metal material while being rotated, and a tool body is driven such that the tool body is moved in a direction away from the second metal material while being rotated. In the working step, a through-hole is formed in the second metal material by the pin member, and then a distal end of the pin member is dug into the first metal material to a predetermined depth position in the first metal material.

Abstract: A method of friction-stir welding, FSW, a joint J, for example a T joint and/or a lap joint, between a first workpiece W1 and a second workpiece W2, is described.

Abstract: A method is provided for producing a common connecting opening in two components, at least one of which is made from a plastically deformable material. In the method, at least the edge region of a first prefabricated opening of the first component is softened in order subsequently to introduce a mandrel which displaces the material softened by the heating so that a common connecting opening having a predetermined diameter is obtained.

Abstract: A device for performing a method for producing a lamination pack, wherein in the method laminations are cut from an electric strip or sheet; the laminations are placed on top of each other to form a lamination stack; the laminations are connected by material fusion to each other by: locally plasticizing a material of the laminations in an edge region of the laminations by generating friction heat by a tool; mixing the locally plasticized material, at least of the laminations neighboring each other, with the tool; and allowing the plasticized material to cool and fuse the laminations in the edge region to form the lamination pack. The device has a punch press and/or a receptacle for one or a plurality of lamination stacks. The device further has a welding tool that is rotatably driven about an axis of the welding tool and moveable transverse to the axis of rotation.

Abstract: Provided is a method for manufacturing a liquid-cooled jacket, to reduce the size of a recessed groove on a surface of a metal member and also to reduce roughness of a jointed surface. The method includes: a placing step of placing a sealing body on a jacket body, a first main joining step of performing friction stirring by moving a main joining rotary tool around to a first overlapped portion, and a second main joining step of performing friction stirring to a second overlapped portion. The main joining rotary tool has a base-end-side pin and a tip-end-side pin. A taper angle of the base-end-side pin is greater than a taper angle of the tip-end-side pin and a stairs-like pin step portion is formed on an outer circumferential surface of the base-end-side pin.

Abstract: A liquid cooling jacket is produced by forming a first butted portion where a step side face of a peripheral wall portion and an outer peripheral side face of a sealing body butt each other and a third butted portion where a step side face of a support pillar portion and a hole wall of the hole portion of the sealing body portion butt each other with a gap, and friction-stirring by inserting a tip side pin and a base side pin of a primary joining rotary tool that is rotating into the sealing body and moving the primary joining rotary tool along the third butted portion with an outer circumferential face of the tip side pin being kept off the step side face while having a second aluminum alloy of the sealing body flow into the gap.

Abstract: A welding and deburring system is provided for joining first and second work pieces to one another. The system includes a friction stir welding tool for joining the first and second work pieces to one another at a weld. The system further includes a deburring tool attached to the friction stir welding tool and removing a material flash generated at the weld. The system further includes one or more nozzles disposed in a fixed position relative to the friction stir welding tool, with the nozzles directing a cryogenic fluid to at least one of the friction stir welding tool, the deburring tool, the first work piece, the second work piece, and the weld.

Abstract: A method for manufacturing a liquid-cooling jacket (1) where heat transfer fluid flows in a hollow part (14) defined by a jacket body (2) and a sealing body (3) includes: an overlapping process in which the sealing body (3) is placed on an end surface (11a) of a peripheral wall part (11) in such a way that the end surface (11a) and a back surface of the sealing body (3) are overlapped each other to form a first overlapped part (H1); and a primary joining process in which primary joining is performed by friction stirring in such a way that a rotary tool (FD) is moved once around a recessed part (13) along the first overlapped part (H1).

Abstract: A process control system and a method for process control of a solid-state additive manufacturing system capable of performing various additive processes, such as joining, additive manufacturing, coating, repair and others, are disclosed. The process control system is capable of simultaneous measuring, monitoring and controlling multiple process variables, viz. material temperature, actuator down force, tool force (or torque), tool position, tool angular and transverse velocity, spindle torque (angular velocity), filler flow rate, filler composition, track width, inert gas flow rate and others. A feeding system for continuous supply of filler material to the solid-state additive manufacturing system is also disclosed. The filler material can be in a form of a powder, granules, briquettes, beads, flakes, wires, rods, films, scrap pieces, sheets, blocks or their combinations.

Abstract: A method for operating a double-action friction stir welding device including a welding tool having a pin member and a shoulder member, a projection/retraction mechanism for causing the pin member to project/retract relative to the shoulder member, a rotation mechanism for rotating a welding tool, and an advancing/retracting mechanism for advancing/retracting the welding tool, the method including cleaning at least one of the outer circumferential surface of the pin member and the inner circumferential surface of a through hole of the shoulder member on the basis of the level of an adhesion parameter correlated with the degree of adhesion of the material of a welding object, caused by friction stir welding, on the outer circumferential surface of the pin member and the inner circumferential surface of the through hole of the shoulder member.

Abstract: The invention relates to a solder ball feeding device, comprising a solder ball reservoir for receiving an amount of solder balls and a metering device for dispensing a metered feeding amount of solder balls to a discharge device, wherein the metering device comprises an ultrasound device and a dispensing nozzle with a dispensing cannula, the ultrasound device serving to apply vibrations to the dispensing nozzle, and the solder ball reservoir or the dispensing nozzle of the solder ball reservoir being provided with a pressure connection which serves to introduce a pressurized gas into the solder ball feeding device.

Abstract: The invention concerns a method for joining a metal component and a polymer component, and a structure comprising said components. In the method, an extrusion die plate with a through hole is placed between the metal component and the polymer component. A probe is rotated and plunged across the thickness of the metal component and eventually through said through hole of the extrusion die plate, thereby extruding a part of the metal component through said through hole of the extrusion die plate into the polymer component. The probe has a rotation axis having an offset to the centre of the through hole during the rotating and plunging action.

Abstract: A method of at least partially filling an opening in a workpiece made of metal, the opening being at least partially defined by one or more opening walls having one or more opening wall surfaces. The method includes providing an insert bondable with the workpiece, the insert having one or more insert engagement surfaces formed for engagement with the opening wall surface. The opening wall surface and the insert engagement surface are heated to a hot working temperature. The insert is subjected to an engagement motion, to move the insert engagement surface relative to the opening wall surface. While the insert is subjected to the engagement motion, the insert is also subjected to a translocation motion to move the insert at least partially into the opening, for engaging the insert engagement surface with the opening wall surface, for at least partially creating a metallic bond between the insert and the workpiece.

Abstract: A reciprocating welding device using a microcontroller to control a stepper motor to control a welding head for the stationary welding of a workpiece, the microcontroller allowing for adjustment of the welding head reciprocating stroke speed, the width of each stroke, and a pause from 0-1 second at the sides to control the wash of the welding edges, having a manipulator, the welding head and the oscillator contained in a single unit and provided on a multiple adjustment portable stand.

Abstract: A welding apparatus is suitable for welding polymeric materials, and particularly but not exclusively those that may be thin or brittle. A welding apparatus is provided for welding polymeric materials along a weld zone of the polymeric material. The welding apparatus has a carrier for supplying heat to the weld zone to cause melting of the polymeric material, wherein the heating element is arranged to reciprocate relative to the carrier between a retracted and an extended configuration, such that as the element moves from the retracted to the extended configuration the heating element melts and penetrates the surface of the polymeric material. The carrier also has a trailing contact surface trailing the heating element along the weld zone arranged to constrain molten polymeric material in the weld zone. The heating element is also arranged to reciprocate relative to the trailing contact surface.