Abstract: In a process for repairing electronic device packages, the problem of removing solder remnants on substrate bonding pads is solved by, first etching a pattern in silicon and metallizing the pattern to make a silicon wick. The solder remnants on the bonding pads are melted, and the etched pattern of the silicon wick is brought into contact with the remnants to remove them by capillary action. It is often convenient to heat the silicon wick so that solder remnants melt when the wick is brought into contact with them.

Abstract: A system and method of interconnecting a first tape automated bonding frame to a substrate so as to facilitate replacement by a second automated bonding frame. The automated bonding frame is formed to include a plurality of signal leads having a pattern of outer lead ends. A semiconductor chip is attached to the inner lead ends of the frame. Connection sites are formed on the substrate to correspond to the pattern of outer lead ends. The substrate bonds of the connection sites to the substrate have a first bonding strength. The outer lead ends are then attached to the connection sites to achieve a second bonding strength less than the first bonding strength. Thus, an application of force on the outer lead ends tends to separate the outer lead ends from the connection sites while leaving the substrate bonds intact. Preferably, the tensile strength of the signal leads is less than both of the above-described bonding strengths.

Abstract: A desoldering vat includes a narrow, elongated, solder pot filled with liquid solder which actually extends slightly above the pot due to the meniscus, and is used to desolder the multiple pins of electronic components, especially elongated components such as edge connectors, which could be as long as 14", with three rows of pins. Adjustable braces on both sides of the pot allow the worker to rest a circuit board against the brace and pot such that the depending pins of the pass-through pins of the components extend into the solder, with the solder in most instances touching the bottom of the printed circuit board. All the pins of the component are thus heated to molten solder temperature at once, permitting the easy removal of the component from the top of the board.

Abstract: Apparatus for rapidly and precisely removing and replacing surface mount devices without disturbance to nearby devices on a printed circuitboard, the invention utilizes a multiple nozzle arrangement wherein nozzles arranged for reciprocating motion one each along each edge of a surface mount device direct low velocity hot gas against bond joint locations along the respective edges of the surface mount device, thereby to melt the bonding agent mounting the device to the circuitboard. The multiple nozzle arrangement of the present system thus allows removal and/or replacement of devices of widely varying dimensions without the need for changes in nozzle size such as is inherent in prior art hot gas rework stations.

Abstract: A solder well configured to abut and enclose the though hole pattern on a printed circuit board to allow the reflow of solder and removal of a multipin electronic component without affecting the integrity of adjacent solder joints of components disposed within or adjacent the through hole pattern.

Abstract: A method and apparatus are described for the removal of solder mounted surface mount electronic components which includes the removal of old solder, broken leads, and the electronic component without damaging other devices on the substrate. A desoldering braid is shaped to cover each of the electronic component's outer lead bonds without contacting the component's base. The desoldering braid is heated and brought in contact with the bonds until the solder flows into the desoldering braid and any broken outer leads attach to the desoldering braid. Upon removal of the desoldering braid the electronic component can be lifted off the surface. The desoldered solder joints will contain a thin uniform coating of solder less than approximately 50 micro inches thick. This allows for removal and replacement of solder mounted electronic components with leads on center lines spaced less than 0.020 inches.

Abstract: A solder bridge between leads of a microelectronic circuit is removed by projecting a laser beam onto the solder bridge with sufficient power to cause the solder forming the bridge to melt and to flow onto a wicking tool placed into contact with the solder bridge. The wicking tool is removed during the heating to remove the solder and debridge the leads. Microelectronic leads having a width of the order of 4 mils and a pitch of the order of 8 mils may be debridged easily using the invention.

Abstract: A technique is provided for desoldering circuit components employing a desoldering aid that fits like a cap on a standard size rectangular circuit component. The aid has a rectangular top of high thermal conductivity metal substantially the same size as the circuit component. At least a pair of integral sides along opposite edges of the top are bent normal to the top and are not further apart than the outside of the electrical leads on the opposite sides of the circuit component for good thermal contact therewith. The depth of the inside of the box is greater than the height of the top of the component so that there is no contact between the top of the box and the top of the component. The top of the box over the component is heated sufficiently to melt solder on the electrical leads. The box and component can then be lifted together from the printed circuit board.

Abstract: The front of a new steel strip is welded to the tail of a strip being formed in a continuous pipe mill or the like at an improved splice station. The ends of the strips are sheared to match and are clamped on a carriage movable in the longitudinal direction of the strips. A pair of pinch rolls downstream from the carriage for holding the tail of the strip in the mill can be translated in a direction transverse to the strip for aligning the tail with the front of the new strip of metal. Movement of the pinch rolls and carriage bring the ends of the strips into alignment and abutment. An automatic welder on the carriage butt welds the seam between the ends of the strips. A milling cutter traverses across the welded seam for removing excess weld bead to prevent damage to rolls in the forming mill.

Abstract: An electronic circuit board rework and repair system having a carriage manually movable to successive station positions and having a table thereon movable along mutually orthogonal axes for positioning of a circuit board clamped to the table. At a first station, a circuit board is loaded onto the table, and a microscope can be swung into position for inspection of the loaded board. At a second station, an intended component or circuit board site can be aligned by way of a visual image of the component and site, and the table locked in position. At a third station, the selected component or circuit board site is automatically in alignment with a programmable heater for selected heating of the component contacts and removal of the component by a pickup probe associated with the heater. The system is calibrated such that there is alignment between a visually established position at the second station and that component position under the heater at the third station.

Abstract: A support apparatus for use during disassembly and reassembly of a vehicular radiator is provided. The support apparatus includes vertically adjustable and rotatable generally horizontal supports and rotatable supports. Adjustable heating elements provide for use of the support apparatus with various size radiators.

Abstract: Described herein is a slag removing apparatus suitable for use on a padi-welding machine, which permits automation of the pad-welding operation and which essentially includes: a C-shaped roller holder located beneath a movable welding torch and provided with a rotational drive mechanism for a roller to be padded; a pair of extension arms horizontally extended on the open side of the roller holder and fixed in vertically adjustable positions; a guide rail support member provided with a rack and bridged between the extension arms in parallel relation with the rotational axis of the roller drive mechanism and detachably at least at one end thereof; a carriage having on a rockable plate a drive motor and a pinion disengageably meshed with the rack and movable along the support member; an inclined mount plate provided on the carriage with a predetermined angle of inclination; and a vibrational beating mechanism holding at least one needle bundle with the fore end thereof in face-to-face relation with the welding s

Abstract: A pallet for conveying a plurality of ceramic leadless chip carriers (LCC) through an automated wave soldering machine. The pallet includes recesses formed to receive and contain the LDD's with the lid of the LCC facing into the recess. This results in protecting the lids from the molten solder. Additionally, the recesses are formed in a diamond orientation with a solderable pin placed at the trailing apex of each recess. Both the pin and the diamond orientation prevents solder build up on the trailing conductive pads, resulting in enhancing the coplanarity of the solder on the pads.

Abstract: A solder reflow machine for removing and replacing electronic components of the pin-grid array type having a large number of leads soldered into a very densely populated printed circuit board. The machine utilizes a heat-transfer liquid and a vacuum to remove the component from the board. The printed circuit board is positioned with the component facing downwardly. A tank containing the heat-transfer liquid is located below the printed circuit board. The apparatus includes a solder reflow head which has a component-engaging vacuum plate with a central opening that is in communication with a vacuum source through a pipe which is pulled downwardly to remove the component. The component is surrounded by a wall in combination with the bottom of the printed circuit board and seals off the liquid flow path.

Abstract: A method for removing excess solder from a printed circuit board is practiced by mixing a quantity of ceramic beads with an oil to form a fluidized bed mixture. The fluidized bed mixture is heated to a temperature above the melting point of a solder on the printed circuit board. A surface of the printed circuit board to be cleaned is placed in contact with the heated fluidized bed and agitated against the bed to remove excess solder.

Abstract: A bobbin assembly for a soldering/desoldering device may be readily produced by utilization of a heater assembly comprising an electrically insulating tape having an etched foil heater in the form of serpentine comprising a plurality of coextensive side by side parallel leg portions bonded to one side thereof. The bobbin assembly is formed by wrapping the heater assembly about a cylindrical bobbin with the heater leg portions parallel to the bobbin axis so as to form a first insulating layer in contact with the bobbin, a layer comprising the heater in contact with the first layer and a second insulating layer in contact with the heater. A wire is then wound about the entire assembly, in a helical manner, to hold all elements in place. Additionally, a dissimilar metal lead may be spot welded to the bobbin to form a thermocouple junction used for sensing the bobbin assembly temperature.

Abstract: A large-diameter welded steel pipe having a straight seam and tab plates attached to its ends as extensions of the seam is laid along a setting line with the seam upward. An apparatus for treating the ends of such a pipe has a tab plate cutting unit and a bead removing unit. The tab plate cutting unit cuts the tab plates off with a torch. The bead removing unit removes the weld beads on the inner surface of the ends of the pipe by cutting them with a rotary cutter.

Abstract: A soldering tip has a sleeve (10) with an insert (14) therein, both formed of good heat conducting material. An annular passage between the sleeve (10) and the insert (14) enables travel of solder therein by capilliary action when heat is applied to the tip and the latter contacts solder. The insert (14) is movable outwardly of the sleeve (10) to discharge solder in the annular passage from the tip.

Abstract: A method of solder leveling in printed circuit boards or other circuitized substrates. Flux is first applied to the surface of the substrate to be soldered. Molten solder is then applied to the fluxed surface after which the soldered substrate is cooled to a temperature below 300.degree. F. Molten solder is then again applied to the previously soldered surface of the substrate. This last step results in leveling the solder first applied to the substrate, including removal of any solder balls which had been formed over recessed pins and flush filling of passage holes formed in the substrate. The method can be performed without regard to the surface condition of the substrate, the composition of flux and solder, whether the substrate is of the thin film type or of the thick film type, nor whether dip soldering or wave soldering techniques are used. The invention also incompasses the end product resulting from use of the method.

Abstract: An equipment for the manufacture of ring members for vehicle wheels starting from metal plate strip cut lengths, which mainly comprises a cylinder bending station formed by a calender, a welding station formed by two discontinuous type welding machines with rollers (which carry out a so-called "ecrease" welding in which the overall lap joint thickness is reduced plastically to about the thickness of one of the lapped end edges), each having a grasping device, intended for grasping the workpiece, movable between an extracted position, in which it extends into the bending station to grasp the workpiece lying therein, and a retracted position, and a rolling station which comprises a pair of rollers, one of which is driven; the welding station is arranged to move, during the welding step, between a first position, in which the first welding machine faces the bending station, and a second position, in which it faces the subsequent rolling station, and the two welding machines alternate in the two mentioned positio

Abstract: The method and apparatus is disclosed to reduce the size of weld flash located at the junction of two workpieces each having a cylindrical contour and which have been butt-welded together. This method and apparatus employ roller members which positively feed the butt-welded workpieces through a slot opening smaller in width than the original diameter of the weld flash. In the preferred embodiment, a roller is spaced apart from the stationary block member to establish the slot opening while the workpieces are rotated while being fed through the opening in order to exert sufficient mechanical force with the sides of the slot opening to reduce the diameter of the weld flash by compaction during passage therethrough.

Abstract: A gas pressure welding machine comprises a movable clamp means for clamping one of reinforcing rods to be joined together, a stationary clamp means for clamping the other reinforcing rod, a punching die for punching-shearing a bulge being formed around a joint portion of the reinforcing rods, and a key connection mechanism for detachably connecting the movable clamp means and the punching die, whereby the reinforcing rods are subjected to pressure butt welding to form a bulge around a joint portion thereof and the bulge is immediately punching-sheared under red heat by the punching die.

Abstract: An apparatus for removing lap soldered circuit packages from the module to which they are soldered is presented. The module is placed over the apparatus with the circuit package on the underneath side. A nozzle of the apparatus is raised so as to be centered below the circuit package, and a heated gas is directed over the lap soldered leads for a predetermined time. When the solder melts, gravity causes the circuit package to fall away from the module. The falling package is caught and held by the nozzle. The nozzle is then lowered away from the module, and as it is lowered, push rods protrude upwardly through the nozzle to support the circuit package and lift it out of the nozzle, thereby positioning the nozzle for easy and safe handling.

Abstract: A solder/desolder tool has a heater block supporting a handle at its upper end and a heating plate at its lower end. The heating plate is thermally engaged by heating elements housed in the heater block. An array of pin relief apertures are formed in the heating plate. Retractable clamps are pivoted to the heater block for clamping a leadless chip against the heating plate. The leadless chip has an array of input/output sockets corresponding to the array of pin relief apertures. A method is disclosed for soldering the chip sockets to a corresponding array of pins supported by a PC board. According to the method, solder balls are loaded in the chip sockets, and the chip is then secured in the tool to reflow the solder balls to form solder plugs. The solder plugs are then set upon the upper ends of the pins and melted by the heating plate so that solder joints are formed between the pins and sockets. The chip is released from the tool to allow the solder joints to cool.

Abstract: Apparatus for manufacturing wheel rim blanks from flat metal strip includes a plurality of work stations through which the metal strip passes to produce a cylindrical ring having a longitudinal axis and a welded joint. The work stations include a strip feed station, a cylinder forming station, a joint orientation station, a joint welding station and finishing stations. The work stations are arranged in a generally Z-shaped configuration with end legs extending in opposite directions from opposite ends of a transverse connecting leg. The strip feed station is located along one end leg, while the finishing stations are arranged along the other end leg. The ring forming, joint orientation and joint welding stations are aligned in succession along the connecting leg. The ring members are received in upwardly open U-shaped supports at the finishing stations and are moved in arcuate paths from the welding station through the finishing stations by an overhead conveyor device.

Abstract: An unsoldering tip for an electrical apparatus for unsoldering of soldering joints and for removing the solder consists of an electrical resistance wire being designed for being connected to an electrical voltage source at its both ends and becoming heated on current flow therethrough. The resistance wire comprises two legs which partially extend in parallel relation and have there a small distance between 0.1 and 0.3 mm. Both these legs are electrically connected one with the other at one end. At that area, where both these legs extend in parallel relation and with a small distance one from the other, a bend of about 180.degree. is provided, where an enlargement of the small distance is provided to form an enlarged open area or arcuate configuration for receiving the joint to be unsoldered, with the maximum spacing between the legs in the enlarged area being between approximately 0.8 and 1.2 mm.

Abstract: A tool for removing soldered IC packages comprises a block of heat-conducting material having a plurality of cylinder-shaped holes with parallel axes; a plurality of heat-conducting rods, each of which has one end that slides in a respective one of said holes; an insulator containing the block having a lid with another plurality of holes which are aligned with at least some of the rods in the block; and means for moving the rods that align with the holes in the lid partway through such holes by distances of unequal length so they can conduct heat from the block to respective I/O pins on the package that lie in multiple planes.

Abstract: A holder for electrically heated temperature controlled soldering instruments includes a hollow housing having a forward portion for sealingly engaging the handle shoulder of the soldering instrument. The forward end of the housing is so arranged that the handle end of the instrument is higher than the tip with the instrument held downwardly at an angle with respect to the central axis of the housing. A hollow cone having an inner heat-reflecting surface is disposed in the housing about the tip. The housing and cone may be evacuated to reduce heat losses. A locking element is pivoted to the forward end of the housing and biased into its closed position to lock the instrument in the holder. The locking element is so designed that the instrument pushes the element into its open position upon insertion. The locking element opens when the operator pulls the instrument out with his finger adjacent the forward end of the housing. The holder includes means on its top for securing thereto another tool.

Abstract: By providing a multi-faced, heat conducting element incorporating projecting heat insulating material in juxtaposed, spaced relationship to the heat conducting element, a unique, inexpensive, readily produced solder pot is achieved for use in removing and replacing multi-pinned components mounted on printed circuit boards. In the preferred embodiment, the multi-faced heat conducting element incorporates a plurality of different faces, with each face corresponding to the pin configuration of a particular multi-pinned component, thereby achieving a single solder pot which can be employed for a plurality of different multi-pinned components. Furthermore, the preferred embodiment incorporates the heat insulating material formed as side panels, mounted at each end of the multi-faced element, with the heat insulating material possessing overall dimensions which expand upon heating to become greater than the outer dimensions of the multi-faced element.

Abstract: A reworking tool for ceramic substrate hybrid circuits has a metal base for sitting on a heated surface, a support member support above the base and a pillar of heat conductive material attached to the base and extending up through an aperture in the support member. The top surfaces of pillar and support member are in a common plane. By this means a "hot spot" is produced at the top of the pillar and a hybrid circuit positioned on the support member can be so positioned that a particular component position is resting on the top of the pillar. Solder at this component position will melt and a component can be removed, or a component added or a component removed and another placed in position. Lateral sliding of the hybrid circuit laterally on the support member enables the solder to solidify.

Abstract: A desoldering tip, adapted to be attached to a standard pencil soldering iron, is formed with a recess adapted to closely fit over a leadless component soldered and adhered with an adhesive to a printed circuit board. Solder present in the recess attaches the component to the tool by molecular attraction. Once the solder and adhesive are melted, the component is readily lifted from the board with the tool. The component is then ejected from the tool.

Abstract: A solder removing device is disclosed for absorbing solder which has been rendered molten by the application of heat, including an open-mesh structure comprising a strand and formed by knitting, as a primary example, at least the surface of the strand being metallic and receptive to solder flux (and indeed being coated with solder flux rendering it more capable of wetting with molten solder). The open-mesh structure enables the device to absorb solder more freely and in greater quantities than can prior braided devices in which the multiple strands are contiguous.

Abstract: An isolator device to electrically insulate and isolate a separate component in a circuit board arrangement to allow for relatively fast and convenient diagnostic inspection of a circuit to locate failed components. The device has an isolator sleeve with a cavity which receives the lead of the component while the lead is in situ on the board. The component lead is electrically insulated from the board circuitry to permit separate testing of the component's integrity.

Abstract: A stand and method for disassembling structures, such as automobile radiators, by separation of first and second parts thereof that are joined by a meltable bonding medium such as solder. The disassembly stand is of a simple frame construction that is provided with an adjusting platform for raising, lowering, and supporting the structure to be separated and clamps for freely suspending the structure with its joint to be separated located so as to be acted upon by a room-shaped heating structure, according to a preferred embodiment. In accordance with an aspect of the method, opposed forces are caused to act upon the parts to be separated while the joint by which they are connected is simultaneously heated along substantially the entire length thereof.

Abstract: An apparatus for internal flash removal is intended for use in pipe manufacture and comprises a hollow supporting bar inserted into a pipe being welded and carrying an oxygen duct with a main nozzle and a cooled ferrite-holder. An additional nozzle having an oxygen conduit common with the main nozzle is arranged downstream of the main nozzle in the direction of welding. The main and the additional nozzles have oval outlets of different clear openings and are arranged at different acute angles to the weld in the same plane passing through the pipe axis and the weld. The apparatus ensures a quality weld surface finish inside the pipe.

Abstract: An improved process and apparatus for continuous production of welded tubes is disclosed wherein a metal strip material is formed into a tubular form, the longitudinal edges thereof welded, and the welded seam cold worked by the application of a high frequency pulsating force to each area of the seam, while it is supported and widened from within.

Abstract: A solder removing device is disclosed including fibres of temperature-resistant non-metallic material, such as a synthetic polymeric material, for example FEP or PTFE, which are coated with a metal rendering them more receptive to solder flux. The metallized fibres are coated with solder flux rendering them more capable of wetting with molten solder, interstices between the fibres serving to absorb molten solder by capillary attraction.

Abstract: Apparatus and method for rework dressing a chip site on a substrate prior to rejoining a chip by solder reflow. A compliant mask is aligned and placed on the substrate so that remnant solder columns on chip site pads protrude through holes in the mask. A brush mechanically removes excess solder and dresses any remaining solder columns to uniform shapes and volumes.

Abstract: A vacuum insulated container is constituted by a double-walled receptacle wherein the space between the walls is substantially evacuated to provide vacuum insulation. The outer wall is provided with an opening therein which is used during manufacture to provide access to the space between the walls so that the space may be evacuated. A stopper- or plug-like portion fills the opening after the container has been evacuated and is permanently joined or bonded to the surfaces of the opening thereby providing a sealing to maintain the vacuum in the space between the walls.

Abstract: Tinning of a plurality of solder bonding surfaces is accomplished by feeding a predetermined length of solder into each of the plurality of pre-heated surfaces. The apparatus provides for the measurement of the solder wire during a non-tinning portion of the machine operating cycle, thereby conserving cycle time.

Abstract: Apparatus for aligning and setting the gap between two rail-ends prior to joining these two ends by fish plating or welding and possibly dressing the weld, comprises a rigid horizontal frame of open structure overlapping the two rails and providing an access area around the two ends to be joined. Two main presses and two end presses are mounted in line on the frame and arranged so that the two main presses are located between the end presses. Each combination of a main press and an end press serves to grip one of the two rails to be joined. The gap setting means can be locked on the two rails and has rams for moving the rails together or apart. Weld dressing means for eliminating the weld bead formed after a weld joining operation comprises a dressing tool movable by the aforesaid rams. The apparatus is especially for use in laying or reconditioning railway lines.

Abstract: A chipper head is removably affixed to the holder head of a welding rod holder in an area spaced from and opposite the point of support of a welding rod whereby the welding rod holder functions as a combination welding rod holder and chipper hammer.

Abstract: A device for removing a solder alloy from a solid soldered joint comprising a multiplicity of metallic strands formed into an elongated wick operable to effect the solder removal through the application of an end portion thereof to the joint in heat exchange relation to a heat source so that when the solder alloy is rendered molten by the heat source it will flow by capillary action from the joint into the applied end portion of the wick, the improved step of each metallic strand of the wick having its exterior surface coated with solidified solder alloy having a melting point substantially below the melting point of tin prior to being formed into the wick so that when the end portion thereof is applied to the joint in heat exchange relation with the heat source as aforesaid the solid solder alloy of the coating on the strands of the applied end portion when rendered molten by the heat source mixes with the molten solder alloy from the joint flowing by capillary action into the applied end portion of the wick

Abstract: A method and apparatus are provided for replacing a commutator on a starter armature in which radially extending, circumferentially spaced commutator contact wires are interspaced between and soldered to mating contact wires on the armature. A heated platen includes at least one receiving hole through which the commutator is placed so that the soldered connection between the commutator and armature contact wires rests against the platen to thereby melt and remove the solder. The commutator is secured in a chuck while the armature is driven away from the stationary commutator. Thereafter, a novel tool spreads the rotor contact wires radially outwardly which permits a subsequent and new commutator to be positioned over the armature shaft so that the new commutator contact wires are interspaced between the armature contact wires. The contact wires between the new commutator and the armature are then soldered together by dipping the assembly into a solder pot heated by the platen.

Abstract: A desoldering wick formed of tin-coated copper strands braided together. The wick is coated with a flux solution which includes a coloring agent such as a dye. In use, the extent to which molten solder has traveled along the wick is visually indicated by a color demarcation line between the portion of the wick still having colored flux thereon and the portion of the wick from which the colored flux has been discharged. The latter portion can then be cut off and discarded.

Abstract: The present invention relates to portable, semiautomatic apparatus for aligning and removing solid state multicontact electrical circuit devices, e.g. DIP (dual-in-line package) chips from printed circuit panels or boards so as to prepare the board for new or replacement chip insertion and soldering.

Abstract: A metal wick to be used for the absorption of molten solder is deoxidized and flux coated by a process that does not involve the application of heat to the wick or the flux. In one embodiment the wick is cleaned by heating in a reducing atmosphere and is then immersed in a coating bath containing a solution of a rosin flux in an organic solvent. On leaving the bath the welted wick enters a low-pressure chamber in which the solvent rapidly evaporates at room temperature. In another embodiment the deoxidized wick is coated with comminuted solid resin by electro-static means.

Abstract: In desoldering soldered joints, an electrically conductive wick or braid, used to absorb molten solder from the joint, is connected to a ground conductor of the circuit of which the joint forms a part, thus preventing possible damage to voltage-sensitive circuit components, for example FET's. A solder-absorbent conductive wick is provided with connecting means for connection either directly or through an intermediate conductor with a ground conductor of a circuit in which a joint is to be desoldered by the aid of the wick. Connection to the circuit conductor may be by way of a first electrical connector portion mating with a second connector portion on a circuit board carrying the circuit. The first connector portion may be mounted on a jig or locating fixture arranged to receive the circuit board.

Abstract: The longitudinal welding seam of a tube is subjected to flexing to obtain strengthening by up and down bending followed by one or multiple stage rolling which in turn is followed by sizing.

Abstract: A solder removing device is disclosed for absorbing solder which has been rendered molten by the application of heat, including an open-mesh structure comprising a strand and formed by knitting, as a primary example, at least the surface of the strand being metallic and receptive to solder flux (and indeed being coated with solder flux rendering it more capable of wetting with molten solder). The open-mesh structure enables the device to absorb solder more freely and in greater quantities than can prior braided devices in which the multiple strands are contiguous.