Systems and methods for modifying parts using synchronized ultrasonic transducers

Abstract

Ultrasonic systems and methods for sealing complex interfaces or for metal forming. Complex interfaces, such as mountain tops, include multiple various layers on the interface, or elliptical or circular nozzles with complex geometries. An example system includes two ultrasonic horns, which are arranged opposite to the gap and the interface is disposed between the two ultrasonic horns. The frequency and phase of the ultrasonic energy are synchronized while the energy is applied while the interface is pressed between the jaws, and uniform energy is applied to both sides of the interface. Another example system includes two ultrasonic transducers that are synchronized in frequency and phase and are used to mechanically vibrate the horns to facilitate sealing or welding the interface or to assist in the metal forming process.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. patent application No. 16 / 863,662, filed on April 30, 2020, and U.S. patent application No. 17 / 074,252, filed on October 19, 2020, each of which is incorporated herein by reference in its entirety. Background Art

[0003] Certain types of packaging or containers may have complex sealing interfaces, with varying numbers of layers sealed along the sealing interface. In some applications, the seal must be airtight, airtight, or must contain liquids without leakage. Conventional techniques for sealing these interfaces are cumbersome and expensive, and may require multiple passes over the same interface to complete the seal, which takes a long time for each item to be sealed. Several preparations or manipulations of the item and / or its sealing interface must also be performed before the seal is formed. These preparations or manipulations introduce additional delays into the sealing process.

[0004] Typically, these items may be composed of or coated with plastic film or polyethylene material (e.g., liquid paperboard), such as pillow wrap, flow wrap, and cartons or other containers, such as milk cartons with so-called gable tops. To seal these items, traditional methods may require different machines to seal different materials, take a relatively long time, and may require multiple passes to create a leak-proof seal, suffer from inconsistent sealing, and may produce substandard seals that create channel leaks, generate scrap, cannot accommodate certain seal shapes, particularly narrow seals, and require extensive maintenance due in part to their complexity and number of moving parts.

[0005] In traditional ultrasonic welding, an ultrasonic stack is energized and the part is pressed between the stack and a fixed anvil. This single stack configuration is challenging for certain applications where the part has multiple layers or other unusual geometries and multiple passes over the same part may be required to produce a high-quality seal or weld.

[0006] Gable tops and other packaging sealing applications with an uneven number of layers (such as 4-2-4-5 layers, spanning the width of the interface to be sealed) exemplify the shortcomings of using a single-stack welder. Assuming that each carton layer absorbs or attenuates approximately 10% of the applied ultrasonic energy / amplitude, when conventional welding passes through 4-5 layers, only approximately 50% of the ultrasonic energy / amplitude remains in the final layer, which is insufficient to produce a reliable seal. If the force, amplitude, or time are increased to compensate for this energy loss, there is a risk of over-welding two layers and potentially burning the outer surface, leaving a visual mark on the product.

[0007] Circular or oval interfaces, such as nozzles or ports, are very challenging to seal using traditional ultrasonic welding techniques. Conventional techniques typically require many welding heads (e.g., up to four) and multiple repetitive movements of the welding heads, e.g., three or more steps, to seal these types of parts. These configurations are large, complex, and introduce delays in the manufacturing process by requiring multiple repetitive ultrasonic movements to perform their welding or sealing tasks. Therefore, a solution that addresses these and other problems is needed. Various aspects of the present disclosure are directed to using ultrasonic energy in a single-pass application to meet these and other requirements, thereby creating a seal on a part with a gabled top, such as a carton.

[0008] Parts made of metal can be deformed using dies to deform the metal into a desired shape. Examples include wire drawing, deep drawing, rolling, extrusion, and forging processes. Some conventional processes utilize lubricants applied externally to the die-part interface to facilitate deformation of the metal through the die. Conventional processes can leave marks on the surface of the metal deformed by the die, and the throughput of the forming process is a function of the speed and force with which the metal can be deformed when forced through the die. There is a need for better solutions for metal forming processes.

[0009] Pillow-shaped bags or bags, or similar containers, can be made from flexible materials such as plastic or nonwoven film, polyester printed onto aluminum and then laminated onto polyethylene, metals including aluminum, foil, fabric, film, polyethylene-coated fiberboard, or liquid paperboard. When placed on rollers, the sections between adjacent bags need to be sealed to securely contain the contents of the bag or bag. Conventional processes typically seal the bag and then cut the sections between adjacent bags to singulate the pouches. First, these double-sealing, post-cutting actions introduce latency into the overall bag assembly and the throughput of the sealing process. Second, the rollers must pause long enough to form a seal between adjacent pouches, and throughput is a direct function of how quickly the seal can be formed. Accelerating this sealing process will increase throughput. Performing the sealing and cutting operations simultaneously or nearly simultaneously will further increase throughput. Summary of the Invention

[0010] According to one aspect of the present disclosure, an ultrasonic welding system for sealing multiple layers of a part together includes: a first ultrasonic welding stack including a first horn having a first welding surface and a second ultrasonic welding stack including a second horn having a second welding surface opposite the first welding surface to define a gap therebetween, wherein the gap is configured to receive the part therein for sealing along a portion of the part; an actuator assembly operably coupled to the first and second ultrasonic welding stacks and configured to move the first welding surface relative to the second welding surface; and one or more controllers operably coupled to the first and second ultrasonic welding stacks and the actuator assembly, the one or more controllers operably configured to cause the actuator assembly to urge the first and second welding surfaces of the first and second horns toward each other until contacting the part, and thereby apply first ultrasonic energy to the part via the first horn and second ultrasonic energy to the part via the second horn such that the frequency and phase of the first and second ultrasonic energies are synchronized when the first and second ultrasonic energies are simultaneously applied on both sides of the part, thereby sealing the part along the portion.

[0011] The frequency may be between 15 kHz and 70 kHz. The part may be a chevron having a different number of layers arranged transversely to the longitudinal direction of the chevron. Alternatively, the part may be a chevron having a different number of layers arranged transversely to the longitudinal direction of the chevron. The amplitude of the first ultrasonic energy may be the same as or different from the amplitude of the second ultrasonic energy.

[0012] The system may also include a first generator generating a first ultrasonic energy and a second generator generating a second ultrasonic energy, wherein the first generator is designated as a master generator that automatically locks feedback from the first ultrasonic weld stack to itself using a phase-locked loop and instructs the second generator, acting as a slave generator, to match its own phase and frequency feedback to the phase and frequency generated by the first generator.

[0013] The part can be constructed of a material including a polymer film, a thermoplastic material, a nonwoven material, a metal foil, or a metal. The part is a pillow-shaped package having an end portion having a varying number of layers arranged transversely to a longitudinal direction of the end portion. The part can include a varying number of layers, the varying number of layers including a first number of layers in a first portion of the portion and a second number of layers in a second portion of the portion along the portion to be sealed, the first number being different from the second number.

[0014] The device can be a pillow pack or a carton or a bag. The part is the spout to be sealed to the bag.

[0015] The first horn may be a rotary horn, and the second horn may be a rotary horn. The controller may also be configured to rotate the first horn and the second horn at the same rotational speed while applying synchronized first and second ultrasonic energies to the part.

[0016] The first generator may include a first output portion and a second output portion, the first output portion being operably connectable to the first transducer and the second output portion being operably connectable to the second transducer. The first transducer is operably connectable to the first welding head and the second transducer is operably connectable to the second welding head.

[0017] The area of the parts joined by remote field welding may be at least 1 / 4 inch or 6 mm from the first welding surface of the first welding head or from the second welding surface of the second welding head.

[0018] According to another aspect of the present disclosure, an ultrasonic welding method for sealing multiple layers of a part together includes the following steps: moving a first welding surface of a first welding head toward an opposite second welding surface of a second welding head to close a gap between the first welding surface and the second welding surface until the first welding surface and the second welding surface contact the part to be sealed along a portion of the part to be sealed; in response to contacting the part, applying first ultrasonic energy to the part through the first welding head, and applying second ultrasonic energy to the part through the second welding head, so that the frequencies and phases of the first ultrasonic energy and the second ultrasonic energy are synchronized when the first ultrasonic energy and the second ultrasonic energy are simultaneously applied to both sides of the part, thereby sealing the part along the portion, and the first welding head and the second welding head are arranged to point at each other.

[0019] The method may further include, in response to sealing the layers together, retracting the first horn relative to the second horn to release the part. The frequency may be between 15 kHz and 70 kHz. The movement may be caused by a rotational motion of the first horn rotating at the same speed as the rotational motion of the second horn.

[0020] The amplitude of the first ultrasonic energy can be the same as or different than the amplitude of the second ultrasonic energy.Also contemplated are devices having at least one seal applied by the methods disclosed herein.

[0021] According to another aspect of the present invention, an ultrasonic welding or metal forming system is disclosed. The system includes a synchronized ultrasonic transducer and comprises: an ultrasonic transducer assembly including a horn having a first part-engaging surface, a second transducer arranged to transmit ultrasonic energy into the horn, and a first transducer; a gap configured to receive a part therein to receive ultrasonic energy from the first and second transducers at an interface through the horn; an actuator assembly operably coupled to the ultrasonic transducer assembly and configured to move the part relative to the gap; and one or more controllers operably coupled to the ultrasonic transducer assembly and the actuator assembly, the one or more controllers operably configured to cause the actuator assembly to urge the part toward the gap until the part is pressed against the first part-engaging surface and thereby apply first ultrasonic energy to the part through the horn via the first transducer and second ultrasonic energy to the part through the horn and via the second transducer, such that the first and second ultrasonic energies are synchronized in frequency and phase when the first and second ultrasonic energies are applied to the part.

[0022] When the first and second ultrasonic energies are applied to the horn by the first and second transducers, the first part-engaging surface of the horn may vibrate back and forth. The vibration of the first part-engaging surface may cause deformation of the part as it moves relative to the gap. This deformation may be a change in the metallic structure of the part, which may be composed of metal, or the deformation may be the sealing of multiple layers of the part to form a seal.

[0023] The horn may have a second part-engaging surface. The system may also include an anvil having a first surface and a second surface. The one or more controllers may be configured to move the first surface of the anvil and the first part-engaging surface of the horn toward each other, and to move the second surface of the anvil and the second part-engaging surface toward each other, thereby creating the first seal and the second seal while the first ultrasonic energy and the second ultrasonic energy are applied to the horn by the first transducer and the second transducer.

[0024] The system may further include a blade disposed relative to the anvil between the first and second surfaces of the anvil. The one or more controllers may be configured to actuate the blade to cut the part along a portion between the first and second seals while or after forming the first and second seals.

[0025] When the first and second ultrasonic energies are applied to the horn by the first and second transducers, the first and second part-engaging surfaces of the horn may vibrate back and forth. The vibrations of the first and second part-engaging surfaces may be in a direction orthogonal to the direction of motion of the part. Alternatively, the vibration direction of the horn may be transverse to the direction of motion of the part relative to the gap.

[0026] The horn may have a second part-engaging surface coplanar with the first part-engaging surface. The system may also include an anvil having a first surface and a second surface coplanar with the first surface of the anvil. The one or more controllers may be configured to move the horn and the anvil toward each other to simultaneously create a first seal and a second seal separated by an inner sealing gap when the first ultrasonic energy and the second ultrasonic energy are applied to the horn by the first transducer and the second transducer.

[0027] The system may also include a blade disposed relative to the anvil between the first and second surfaces of the anvil, wherein one or more controllers are configured to actuate the blade to cut the part in the gap within the seal while or after forming the first and second seals. The horn may be a resonant horn. The part may be a wire drawn through the die using the ultrasonic transducer system disclosed herein.

[0028] According to another embodiment, a method of vibrating a horn relative to a part contacting the horn using synchronized ultrasonic transducers is disclosed. The method includes: receiving a part in a gap defined at least in part by a horn of an ultrasonic transducer assembly, the ultrasonic transducer assembly including the horn, a first transducer, and a second transducer, each of the first transducer and the second transducer being arranged to transmit ultrasonic energy into the horn, the horn having a first part-engaging surface; moving the part toward the gap via an actuator assembly operably coupled to the ultrasonic transducer assembly until the part contacts the first part-engaging surface; and, in response to the part contacting the first part-engaging surface, applying a first ultrasonic energy to the part via the horn via the first transducer and a second ultrasonic energy to the part via the horn via the second transducer simultaneously, such that the first ultrasonic energy and the second ultrasonic energy are applied to the part in a synchronized manner in frequency and phase.

[0029] When the first and second ultrasonic energies are applied to the horn by the first and second transducers, the first part engaging surface of the horn can vibrate back and forth. The vibration of the first part engaging surface can cause the part to deform when the part moves relative to the gap.

[0030] The deformation is a change in the metal structure of the part. The part may be made of metal. The deformation may be a sealing of multiple layers of the part to form a seal.

[0031] The horn may have a second part-engaging surface. The method may further include moving the first surface of the anvil and the first part-engaging surface of the horn toward each other, and simultaneously moving the second surface of the anvil and the second part-engaging surface toward each other, thereby creating the first seal and the second seal while the first and second ultrasonic energies are applied to the horn by the first and second transducers.

[0032] The method may further include, in response to simultaneously forming the first and second seals, actuating a blade disposed relative to the anvil between the first and second surfaces of the anvil to cut the part along a portion between the first and second seals.

[0033] The method may also include: when the first ultrasonic energy and the second ultrasonic energy are transmitted into the welding head by the first transducer and the second transducer, the welding head and the anvil move toward each other, thereby simultaneously generating a first sealing portion and a second sealing portion separated by an internal sealing gap, and the welding head has a second part bonding surface that is coplanar with the first part bonding surface.

[0034] The method may further include actuating a blade to cut the part at the inner seal gap in response to simultaneously creating the first seal and the second seal, the blade being disposed relative to the anvil between the first and second surfaces of the anvil.

[0035] The welding head may include a cutting blade. The first part-engaging surface may be a cutting edge. The cutting blade may be configured to vibrate back and forth when the first ultrasonic energy and the second ultrasonic energy are applied to the cutting blade by the first transducer and the second transducer. The height of the cutting blade may be less than the thickness of the part through which the cutting blade cuts. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is a diagram of an ultrasonic welding system used to seal multiple layers of a part together.

[0037] Figure 2 Shown is a pillow pack and the number of different layers to be sealed along its ends to form a hermetically sealed pack.

[0038] Figure 3A Various configurations of cartons are shown, illustrating the number of folds required to form the multiple layers in the gabled top of the carton.

[0039] Figure 3B A close-up view of the top of the chevron is shown, illustrating the different layers that exist along the width, height, and depth dimensions of the chevron.

[0040] Figure 4A An exemplary ultrasonically welded stack is shown with dual horns positioned directly opposite each other to define a gap between which the part is inserted to seal all the layers together.

[0041] Figure 4B Shown Figure 4A Ultrasonic welded stack with the horns closed together. For ease of illustration to show the horns, the parts to be sealed have been removed from between the horns.

[0042] Figure 5AA dual stack setup is shown configured to perform a "scrub" welding action using synchronized ultrasonic energy applied by the respective welding heads of each stack.

[0043] Figure 5B is a cross-sectional view showing the respective side welding surfaces of two horns abutting each other to seal a part interposed therebetween using synchronized ultrasonic energy applied simultaneously by both horns.

[0044] Figure 5C An example configuration is shown for performing a scrubbing-type welding action using synchronized ultrasonic energy applied simultaneously to opposing welding tips.

[0045] Figure 5D Shown Figure 5C The same configuration as shown in , except that the two horns are spaced a distance apart so as to receive in the gap therebetween the interface of the parts to be sealed or joined together using simultaneous ultrasonic energy applied simultaneously to the dual horns.

[0046] Figure 6A Another example configuration for sealing or joining a nozzle or non-planar structure to a part using synchronized ultrasonic energy applied simultaneously to dual opposing horns is shown.

[0047] Figure 6B is a top perspective view of the top welding surface of a bottom one of the horns showing a groove pattern corresponding to a nozzle or non-planar structure to be joined using synchronized ultrasonic energy applied simultaneously to dual opposing horns.

[0048] Figure 6C yes Figure 6A Shown is a front view of two welding heads with a feature such as a nozzle inserted between the opening between the two welding heads when the two welding heads are pressed against each other.

[0049] Figure 7 are example waveforms of ultrasonic energy applied to the first and second horns that are synchronized in frequency and phase according to aspects of the present disclosure.

[0050] Figure 8A is a front view of a dual rotary horn configuration whose frequency, phase, and angular velocity are synchronized with welding or sealing together layers of a part, such as those comprised of a nonwoven material.

[0051] Figure 8B yes Figure 8A The rear view of the dual rotary welding head structure is shown.

[0052] Figure 9A An ultrasonically assisted wire drawing process using multiple synchronized ultrasonic transducers is shown.

[0053] Figure 9BAn ultrasonically assisted metal deep drawing process using multiple synchronized ultrasonic transducers is shown.

[0054] Figure 9C An ultrasonically assisted metal extrusion process using multiple synchronized ultrasonic transducers is shown.

[0055] Figure 9D An ultrasonically assisted metal forging process using multiple synchronized ultrasonic transducers is shown.

[0056] Figure 9E An ultrasonically assisted metal rolling process using multiple synchronized ultrasonic transducers is shown.

[0057] Figure 10 Exemplary vertical form, fill and seal (VFFS) packaging systems and horizontal form, fill and seal (HFFS) packaging systems are shown, into which any of the ultrasonic welding systems disclosed herein may be incorporated.

[0058] Figure 11A is a perspective view of an ultrasonically assisted "cut and seal" assembly having dual ultrasonic transducers that apply synchronized ultrasonic energy to a weld head using a "scrubbing" motion to seal one or more interfaces on a part.

[0059] Figure 11B yes Figure 11A A side view of the ultrasonically assisted cutting and sealing assembly is shown.

[0060] Figure 11C yes Figure 11A A perspective view of an ultrasonically assisted cutting and sealing assembly is shown with the components positioned between the horn and anvil.

[0061] Figure 11D yes Figure 11C A perspective view of an ultrasonically assisted cutting and sealing assembly is shown where a part is pressed between a horn and anvil to simultaneously form two sealing interfaces on the part.

[0062] Figure 11E yes Figure 11D A side view of the ultrasonically assisted cutting and sealing assembly is shown.

[0063] Figure 11F yes Figure 11E An enlarged side view of the ultrasonically assisted cutting and sealing assembly is shown to illustrate the two sealing interfaces between the horn and the anvil, and the blade within the anvil cutting the part to separate the leading portion from the remainder of the advancing roll.

[0064] Figure 12 yes Figures 11A to 11FColor illustration of a finite element analysis (FEA) of an ultrasonically welded stack assembly used in , having a horn between dual transducers arranged to inject ultrasonic energy into the horn.

[0065] Figure 13A is a perspective view of an ultrasonically assisted "cut and seal" assembly having dual ultrasonic transducers applying synchronized ultrasonic energy to a resonant horn that captures a roll having multiple layers between the horn and anvil.

[0066] Figure 13B yes Figure 13A A perspective cutaway view of an ultrasonically assisted "cut and seal" assembly is shown to illustrate a blade positioned between an anvil adjacent a horn, the anvil having a corresponding opening or slot to receive the blade therein when actuated into the horn to cut a part disposed between the horn and the anvil.

[0067] Figure 13C Shown Figure 13A and Figure 13B Two color illustrations of the FEA analysis of the horn shown in to illustrate the exaggerated direction of bending or movement of the horn when different phases of ultrasonic energy are delivered into the horn from the dual transducers from opposite sides of the horn.

[0068] Figure 14A is a perspective view of an ultrasonically assisted "cut and seal" assembly having dual ultrasonic transducers applying synchronized ultrasonic energy to a resonant horn that captures a roll having multiple layers between the horn and anvil.

[0069] Figure 14B Shown Figure 14A Two color illustrations of the FEA analysis of the horn shown in to illustrate the exaggerated direction of bending or movement of the horn when different phases of ultrasonic energy are delivered into the horn from opposite sides of the horn from dual transducers.

[0070] 15A is a top or bottom view of a cutting blade sandwiched between two ultrasonic weld stack assemblies, the transducers of the ultrasonic weld stack assemblies outputting synchronized ultrasonic energy into the cutting blade.

[0071] 15B is a side view of the cutting blade and ultrasonically welded stack assembly shown in FIG. 15A .

[0072] Figure 16A is a perspective view of a rotatable resonant cutting blade sandwiched between two ultrasonic welding stack assemblies, the transducers of which output synchronized ultrasonic energy into the cutting blade, which operates like a resonant horn.

[0073] Figure 16B yes Figure 16A A side view of the cutting blade assembly is shown.

[0074] Figure 16C yes Figure 16A An end view of the cutting blade assembly is shown.

[0075] Figure 17A yes Figure 16A A perspective view of a rotatable cutting blade assembly is shown cutting through a thick block of matter, such as food.

[0076] Figure 17B yes Figure 17A An end view of the rotatable cutting blade assembly is shown with the dual ultrasonic weld stack assembly visible.

[0077] Figure 17C yes Figure 17A A side view of the rotatable cutting blade assembly is shown.

[0078] Figure 18A is a functional illustration of a cutting blade configured to cut through a substance having a thickness T1 from either the top or bottom of the cutting blade surface.

[0079] Figure 18B is a functional illustration of a cutting blade configured to cut through a material having a thickness T2 >> T1 and also greater than the height of the cutting blade.

[0080] Figure 18C is a functional illustration of a cutting blade showing how the cutting blade can be rotated to cut a block of material at least twice per complete rotation of the cutting blade. DETAILED DESCRIPTION

[0081] The surprising result discovered by the inventors disclosed herein is that a very good seal (air and liquid proof) can be formed using a dual horn that delivers energy at ultrasonic frequencies when the frequency and phase of the dual horns are synchronized. As used herein, the phase is synchronized when the two waveforms are aligned at 0 degrees ("push-push") or 180 degrees ("push-pull"). Any other angle is considered asynchronous. Advantageously, only one pass is required to form the seal, and the seal can be formed in as little as one second or less by a single application of ultrasonic energy (e.g., 0.35 seconds). The seal does not leak and works particularly well when the interface to be sealed has a complex number of layers to be sealed together. For example, a so-called mountain top on a milk carton or the like may have a sealed interface that includes two layers at one end of the interface, up to four layers at another portion of the interface, and possibly five layers at the other end of the interface, depending on how the carton blank is folded. The sealing problem becomes particularly challenging when attempting to seal across an interface where different layers exist in different portions along the area of the interface to be sealed.

[0082] Examples of these complex interfaces to be sealed can be found in Figure 2 、 Figure 3A 、 Figure 3B and Figure 6C Seen in.

[0083] Ultrasonic transducers are devices that convert energy into sound, typically in the form of ultrasonic vibrations—sound waves with frequencies above the normal range of human hearing. One of the most common types of ultrasonic transducers in modern use is the piezoelectric ultrasonic transducer, which converts electrical signals into mechanical vibrations. Piezoelectric materials, traditionally crystalline structures and ceramics, are materials that generate a voltage in response to applied mechanical stress. Because this effect also works in reverse, a voltage applied to a sample of piezoelectric material will generate mechanical stress within the sample. Consequently, properly designed structures made from these materials can bend, expand, or contract when an electric current is applied to them.

[0084] Many ultrasonic transducers are tuned structures that include a piezoelectric ("piezoresistive") ceramic ring. The piezoelectric ceramic ring is typically made of a material such as lead zirconium titanate ceramic (more commonly known as "PZT"), which exhibits a proportional relationship between the applied voltage and the mechanical strain (e.g., thickness) of the ring. The electrical signal is typically provided at a frequency that matches the resonant frequency of the ultrasonic transducer. In response to this electrical signal, the piezoelectric ceramic ring expands and contracts to produce large-amplitude vibrations. For example, a 20 kHz ultrasonic transducer typically produces a peak-to-peak (pp) amplitude of 20 microns. The electrical signal is typically provided by a power supply as a sine wave, which conditions the signal to produce consistent amplitude mechanical vibrations and protect the mechanical structure from excessive strain or sudden changes in amplitude or frequency.

[0085] Typically, the ultrasonic transducer is connected to an optional ultrasonic amplifier and sonotrode (often also referred to as a "weld head" in the ultrasonic welding industry). Both the amplifier and sonotrode are typically tuned to have a resonant frequency that matches the resonant frequency of the ultrasonic transducer. The optional ultrasonic amplifier, which is structured to allow for mounting of the ultrasonic transducer assembly (or "stack"), is typically a tuned half-wave component configured to increase or decrease the amplitude of the vibrations passing between the converter (transducer) and the sonotrode (weld head). The amount of increase or decrease in amplitude is referred to as "gain." The sonotrode structure, typically a tapered metal rod, is configured to amplify the amplitude of the oscillating displacement provided by the ultrasonic transducer, thereby increasing or decreasing the ultrasonic vibrations and distributing them over the desired work area.

[0086] Typically, all mechanical parts used in an ultrasonic transducer assembly must be configured to operate at a single resonant frequency close to or at the desired operating frequency. Furthermore, the ultrasonic transducer assembly must often operate with a vibratory motion parallel to the assembly's principal axis (i.e., central longitudinal axis). The power supply for the stack typically operates as part of a closed-loop feedback system that monitors and regulates the applied voltage and frequency.

[0087] For certain applications, particularly those involving welding thermoplastic parts together, ultrasonic welding technology is highly desirable due to its consistency (particularly when the motion of the stack is controlled by a servo-driven motor), speed, weld quality, and other advantages. The inventors have discovered that utilizing dual horns to synchronously apply ultrasonic energy to a complex interface having multiple layers across the area to be sealed surprisingly produces an excellent airtight and hermetic seal in a single pass by matching the phase and frequency of the energy delivered by the two horns and applying the energy on either side of the complex interface. The power to each horn is controlled by an ultrasonic generator that delivers consistent and reliable energy to the horns even in noisy environments. An example of such an ultrasonic generator suitable for use in conjunction with the systems and methods described herein is disclosed in U.S. Patent No. 7,475,801, which is incorporated herein by reference in its entirety, and a suitable ultrasonic generator is available under the brand name iQ TM Commercially available from Dukane. Each welding head can be made by iQ TMAn ultrasonic generator or similar generator capable of outputting a consistent and reliable ultrasonic energy signal through the horn to one or more parts to be welded or joined is driven. Because the components and structure of the ultrasonic generator are well known to those skilled in ultrasonic welding, a detailed description thereof is omitted for the sake of brevity, as such a detailed description is not necessary for understanding the invention disclosed herein. Each horn (or technically, the transducer of the horn) can be powered by a separate power supply, or can be powered by a single power supply with independently controllable dual power outputs. With higher energy amplitudes, the entire pass or cycle time from applying force to the horns 106, 108 to removing ultrasonic energy can be very fast, for example, 0.35 seconds or even faster.

[0088] The force applied to the parts to be sealed can be adjusted within a reasonable range, such as + / - 50% of the nominal value for each size of machine or part. The geometry, material, and desired end product of the part dictate the choice of operating frequency (for example, as a general rule, lower frequency and higher amplitude for larger parts, higher frequency and lower amplitude for smaller parts). In ultrasonic welding, three parameters essentially need to be adjusted to achieve a high-quality, consistent weld for a specific part: a) amplitude; b) force; and c) weld time (the time the ultrasonic energy is applied to the part). Most applications require a short weld time to maximize production, particularly in packaging applications that fill and seal hundreds or thousands of packages per hour. The amplitude is typically limited by the stress in the welding head, so there is a practical limit to how high the amplitude can be set. This leaves a residual force, but increasing the force quickly results in a good weld. Too much force can restrict the movement of the ultrasonic stack and damage or even break it. Alternatively, the stack can become stuck, similar to the jaws closing against a brick wall. If the brick wall does not yield, the stack's movement will be difficult to maintain. Mountain-shaped tops require greater force, while pillow-shaped packages require less force applied by the welding head. Thin films will require different amplitude and force ratios, which may also be based on material and speed requirements. The systems and methods disclosed herein allow for greater flexibility and significantly open the process window, meaning the process becomes less sensitive to common production variables and more robust than conventional methods.

[0089] Figure 1 is an ultrasonic welding system 100 for sealing together multiple layers of a part 110. The system 100 includes two ultrasonically welded stacks (e.g., Figure 4A and Figure 4B), the ultrasonic weld stack includes a first transducer 102 and a second transducer 104. The system 100 includes a first horn 106 having a first weld surface 106a opposite a second weld surface 108a of a second horn 108, thereby defining a gap 112 between the first weld surface 106a and the second weld surface 108a. The gap 112 is configured to accommodate a part 110 having a different number of layers therein that will be sealed along a portion of the part 110. For ease of illustration, Figure 1 1 shows a portion of a part 110 to be sealed in an exaggerated and slightly expanded form, thereby showing, from left to right, the different numbers of layers present in this example part 110. In reality, when present in the gap 112, these layers will press against each other. Figure 1 Starting from the left side of the figure, as shown by the dotted line, the first portion of the part 110 to be sealed has four layers, followed by the second portion having only two layers, followed by the third portion having four layers, and finally the fourth portion having five layers. This type of interface can typically be found in a structure having a structure such as Figure 3A Found in the carton with the gable top shown. Figure 3A The exemplary carton is shown in a fully assembled configuration, folded in half, and fully unfolded into a flat starting configuration. In the latter configuration, the complexity of the folds and layers can be seen at the top of the flat carton, where there are five sections 340a to 340f. When these five sections are folded to form the mountain-shaped top 334, the five sections produce a Figure 1 The illustrated interface has multiple layers. The area of the horns 106, 108 that contacts the part to be sealed is referred to herein as the "weld surface," meaning the weld surface is the contact surface of the horn that contacts the part and through which ultrasonic energy is transferred to the interface of the part to be sealed to weld (or seal) the interface. The ultrasonic energy passes through the horn, exits the weld surface, and enters the part in contact with the corresponding horn weld surface. Each weld surface 106a, 108a of the horns 106, 108 physically contacts a different area of the part to be welded (the sealing interface of the part), for example, in the case of a mountain top, on either side of the mountain top formed when all layers are sealed together.

[0090] The interface to be sealed may have a different number of layers not only in its width but also in its height, e.g. Figure 3B Here, as shown in the figure, at least five parts 350a, 350b, 350c, 350d, 350e need to be sealed together to form an airtight seal. For example, along Figure 3BThe illustrated interface 110, 310, along its elongated width dimension, has four sections, starting from left to right with four layers 350b, followed by two layers 350c, then four layers 350d, and terminating with five layers 350e. However, above these sections along the height dimension, there is an elongated section 350a with only two layers. Thus, taken along the height dimension (which is transverse to the longitudinal direction of the gable top 310), there is only one section in the middle of the interface 310 where two layers exist in the area to be sealed. Elsewhere, there are different numbers of layers above and below the corresponding section of the interface 310 to be sealed. This type of gable top 334 is particularly difficult to seal because the number of layers varies across its width, height, and depth (due to varying thicknesses of the different layers). Traditional adhesive-free methods are time-consuming and require multiple passes along the interface, or simply do not produce an airtight seal that prevents all liquid from escaping. The carton 330 may also sometimes include a plastic spout 332 protruding from the gable top to facilitate pouring. The gable top 334 can be opened on a milk carton for pouring out the liquid contents of the carton 334. The present invention is particularly suitable for sealing gable tops that have many different layers in all three dimensions.

[0091] Another type of part having a similar type of interface to be sealed is a pillow pack 230, such as Figure 2 As shown, the pillow-shaped package has a top or end that is similar to a mountain-shaped top. The pillow-shaped package is usually first joined at a first seam extending longitudinally along the package, and this seam presents an area with multiple layers. The end 210 of the pillow-shaped package 230 also has multiple layers, as shown in the legend. In this configuration, sometimes referred to as 4-2-4-2-4, there are four layers in the first part of the end 230, followed by two layers, then four layers, then two layers, and finally four layers. Thus, different numbers of layers are arranged in the longitudinal direction of the mountain-shaped top 210 of the pillow-shaped package 230. Similarly, this type of part with different numbers of layers has special challenges to sealing. The synchronous double welding head / stacking portion configuration of the present disclosure can seal the pillow-shaped package so that the pillow-shaped package is airtight without any leakage. Figure 2 The pillow packaging shown and Figure 3A The illustrated carton 330 may be made from a polymer film or a thermoplastic material.

[0092] Another type of part having an interface that can be sealed using the invention disclosed herein is a fluid-filled pouch having a valve or pierceable sealing element that can be pierced, for example, by a straw, such as described in U.S. Patent Application Publication No. 20040161171A1. 5A to 5D An exemplary system configured to seal a fluid-filled pouch using the ultrasonic technology disclosed herein is shown and described. ®Selling popular types of pouches. Combined Figures 6A to 6C An example system configured to seal a part having a spout using the ultrasonic techniques disclosed herein is shown and described.

[0093] In a liquid-filled pouch, when liquid is already present in the pouch before the pouch is sealed, the simultaneous ultrasonic energy from the dual horns generates vibrations at the interface that push the liquid away from the interface area, further aiding in creating a hermetic seal. In other words, a surprising benefit of applying dual simultaneous ultrasonic energy to a liquid-filled part is that the vibrations generated by applying energy from both sides of the interface to be sealed tend to vibrate away any liquid droplets present around the interface, allowing the layers of the interface to seal together without trapping liquid therebetween and risking leaks. Microscopic leaks also present health and respiratory risks, allowing bacteria or other pathogens to enter the sealed bag or mold to form around the seal. Additional advantages can be seen in the simultaneous dual horn configuration disclosed herein by forming a hermetic seal in a single pass of the dual horns, where liquid is dislodged by vibrations generated by applying ultrasonic energy from both sides of the opening of the liquid-filled bag at the interface before sealing.

[0094] Back to Figure 1 The system includes an actuator assembly 116 operably coupled to the ultrasonic weld stack ( Figure 4A and Figure 4B ), and is configured to move a first welding surface 106a of the first welding head 106 relative to a second welding surface 108a of the second welding head 108. The movement of the welding heads 106, 108 together can be assisted by respective frames 130, 132, to which the respective welding heads 106, 108 are coupled, the frames 130, 132 forming part of an actuator assembly that moves the welding heads 106, 108 together and apart from each other. One movement in which the welding heads 106, 108 are clamped together to the part to be sealed and then separated after ultrasonic energy is applied to the part is referred to as a single pass or cycle. The actuator assembly 116 can include one or more motors, such as servo motors. The two welding surfaces 106a, 108a are directly opposite each other and form mutually parallel planes that are orthogonal to the orientation of the welding heads 106, 108. The two welding heads 106, 108 can be viewed as moving toward each other like a jaw that opens and closes so that their exposed end welding surfaces 106a, 108a contact the corresponding opposing surfaces of the parts or part interfaces to be sealed. The corresponding ultrasonic energy transmitted from the transducers 102, 104 to the welding heads 106, 108, synchronized in frequency and phase, is output in opposite directions along the same dimension. Each of the dual ultrasonic welding stacks can include an optional booster 140, 142, such as Figure 4AAs shown, the boosters amplify the energy emitted from the transducers 102, 104 before entering the welding heads 106, 108. Likewise, the presence of the boosters 140, 142 is optional and Figure 5A and Figure 6A The configurations shown in lack the intensifier. In these configurations, the transducers 102, 104 are mounted directly to the welding heads 506, 508 ( Figure 5A ) and welding heads 606, 608 ( Figure 6A ).

[0095] A controller 120, which may be one or more controllers, is operably coupled to the ultrasonic welding stack and the actuator assembly 116. The controller 120 is configured to cause the actuator assembly 116 to push the first welding surface 106a and the second welding surface 108a of the welding heads 106, 108 toward each other until contact is made with the part 110. A predetermined force may be applied to the welding heads 106, 108 to substantially clamp the part 110 between the welding surfaces 106a, 108b and hold the folded layers together. For example, the maximum force applied by the welding heads on the part 110 may be set at 4500N, but will depend on the application including the thickness of the interface and the materials to be joined together. The controller 120 applies a first ultrasonic energy to the part 110 via the output of the first welding head 106 and applies a second ultrasonic energy to the part 110 via the output of the second welding head 108 such that when the first ultrasonic energy and the second ultrasonic energy are simultaneously applied to both sides of the part 110, the frequency and phase of the first ultrasonic energy and the second ultrasonic energy are synchronized, thereby aligning the weld, such as in FIG. Figure 3B The layers 350a, 350b, 350c, 350d, 350e shown in FIG are sealed together. As mentioned above, an exemplary ultrasonic generator suitable for generating ultrasonic energy into the welding head through a transducer is described in U.S. Patent No. 7,475,801 and is available from Dukane at any iQ TM The ultrasonic generator was purchased commercially.

[0096] Synchronization of two ultrasonic generators can be achieved by providing a communication connection between the two generators so that the outputs of the two generators to the transducers 102 and 104 are synchronized in frequency and phase. Alternatively, a generator such as that described in the aforementioned patent can be modified to provide two outputs that are synchronized in frequency and phase and provided to the respective transducers 102 and 104. The generators (whether separate generators or integrated via dual outputs) can be arranged in a master-slave relationship, with one of the generators designated as the master generator. A phase-locked loop (PLL) is used to automatically lock the phase of the master generator to the feedback of its ultrasonic stack, and the master generator instructs the slave generator via the communication connection to simulate the same phase at zero crossings (0 or 180 degrees) and ignores the slave generator's own phase and frequency feedback. This allows the phase of the slave generator to drift in the same manner as the master generator. For example, due to thermal effects, phase drift may occur, thus allowing the phase to be synchronized in the two transducers 102, 104 by locking the phase of the slave generator to the master generator (and thus by implying frequencies corresponding to zero crossings of the phase of the ultrasonic energy signal).

[0097] Figure 7 Example waveforms of synchronized ultrasonic energy applied to the first and second transducers 102, 104 are shown, and are not drawn to scale. Synchronous, as used herein, means that the energy has the same frequency f1 and phase. The amplitude A can be the same for both horns or different. Depending on the thickness of the part closest to the horns 106, 108 and the application, a different amplitude can be applied by the first horn 106 relative to the second horn 108. Just as the frequency f1 is matched in the two horns 106, 108, the phases of the two energies are also synchronized in time so that the zero crossings and peaks of the energy over time coincide at the same time, as shown in FIG. Figure 7 As shown by the dashed line in . The frequency f1 of the energy generated in one horn 106 (or transducer 102) can be within 3 Hz of the energy generated in the other horn 108 (or transducer 104). Using two synchronized horns reduces the energy attenuation through multiple layers, such as when sealing a gable top, by half, compared to a single horn configuration. For example, in a single-stack configuration, ultrasonic energy must pass through 4-5 layers of the gable top, resulting in up to approximately 50% ultrasonic energy / amplitude attenuation or loss. In contrast, when using synchronized dual horns according to the present disclosure, the energy from one horn only passes through 2 or 2.5 layers (the energy from the other side similarly only passes through half the number of layers compared to a single-stack configuration), resulting in energy / amplitude losses of only approximately 20-25%, resulting in a high-quality weld or seal without burning layers or creating any visual artifacts on the outer surface of the sealed interface.

[0098] It has been found that the frequency of the ultrasonic energy delivered to the horns 106, 108 by the two transducers 102, 104 is between approximately 15-70 kHz (e.g., ±10%). Particularly effective results have been seen at 15 kHz, 20 kHz, and 30 kHz. The frequency and phase of the ultrasonic energy delivered to the horns 106, 108 by the two transducers 102, 104 to seal the part are synchronized in time so that the peak amplitude of the ultrasonic energy is delivered simultaneously to both sides of the part to be sealed. The amplitude of the ultrasonic energy can be independently controlled on the two transducers 102, 104. Frequencies of 20-35 kHz are particularly suitable for sealing smaller or thinner packages, while higher frequencies can be used to seal larger or thicker packages.

[0099] exist 5A to 5D An exemplary "scrubbing" configuration is shown in FIG. In this configuration, two transducers 102, 104 are synchronized in frequency and phase as in the previous configuration, but the horns 506, 508 are positioned so that their sides touch, pressing against the interface of the parts to be sealed, such as a thin film with a thickness ranging from 10-20 μm or even exceeding 100 μm, or a thin nonwoven membrane whose thickness may vary along the length of the interface. The thickness may vary by ±2 μm at unpredictable locations along the length of the interface. Thus, while the energy application may be uniform, the thickness of the interface (e.g., the interface may consist of only two layers being sealed together) may vary along the length of the sealed interface, creating the risk of small leaks in the seal or resulting in an uneven weld. When frequency- and phase-synchronized ultrasonic energy is delivered to the horns 506, 508 via the transducers 102, 104, the so-called scrubbing action balances out the slight mechanical Y-axis motions caused by the vibrations of the two horns 506, 508 relative to each other. These vibrations create very short, rapid back and forth motions in the horns 506, 508, similar to a scrubbing motion, which has been found to produce very high quality hermetic seals where the interface has a non-uniform thickness, such as when the interface is a thin or nonwoven membrane. 5A to 5D The configuration shown in also allows for more gentle control of the amplitude and force applied to the thin interface and allows for a wider processing window.

[0100] exist Figure 5AIn FIG, each of the two ultrasonic weld stacks includes a transducer 102, 104 and a horn 506, 508. The horns 506, 508 are positioned adjacent to each other, with their respective side weld surfaces 506a, 508a moving toward each other. These weld surfaces 506a, 508a are parallel to the YZ plane and extend a length along the Z axis. Ultrasonic energy is applied along the Y axis by the transducer 102, and ultrasonic energy is applied in the opposite direction along the Y axis by the second transducer 104. The side surfaces 506a, 508a vibrate against each other when a part is positioned between them and ultrasonic energy of synchronized frequency and phase is applied simultaneously by the horns 506, 508. A thin film or nonwoven material forms a hermetic seal with only a single pass of ultrasonic energy through the horns 506, 508. Only two horns 506, 508 and one pass are required to produce a consistent hermetic seal without burning, visual artifacts, or microscopic leaks. While films or nonwovens have been described in these examples, the scrubbing aspects disclosed herein also work with welding metal films, metal foils, or thin metals, or any combination of films, nonwovens, or metals. For example, scrubbing is particularly effective when sealing metals together, but also when sealing dissimilar materials together, such as sealing a nonwoven to a metal film or foil.

[0101] exist Figure 5B , a close-up of the two side weld surfaces 506a, 508a can be seen from the weld heads 506, 508. Compared to the flat side weld surface 508a, the weld surface 506a extends away to form a smaller exposed surface area. In this way, when the part 110 is positioned between the two weld heads 506, 508, the side weld surface 506a acts as a "scrubber" as it moves rapidly back and forth in the Y-axis direction under the influence of ultrasound. Figure 5C An exemplary configuration can be seen in FIG, where horns 506, 508 are in contact with one another. Part 110, which may be, for example, a bag with an open end that needs to be sealed, has the open end positioned between horns 506, 508. This "scrubs" the two layers of the interface as ultrasonic energy is applied from opposite sides. The mechanical action combined with the heat generated by the ultrasonic energy synergistically creates a hermetic seal without artifacts or microscopic leaks. Figure 5DThe horns 506, 508 are shown spaced apart. The interface 110 of the parts is located in the gap between the two side weld surfaces 506a, 508a, which are urged toward each other along the X-axis until the side weld surfaces 506a, 508a contact opposite sides of the interface 110. When ultrasonic energy is applied to the horns 506, 508 via the transducers 102, 104, forces are applied to the horns 506, 508, generating minute mechanical vibrations known as a scrubbing action along the melt of the interface 110, where the weld surfaces 506a, 508a are pressed against. Once the horns 506, 508 are retracted, a hermetic seal exists at the interface 110 of the parts, requiring only one pass or movement of the horns 506, 508 and one simultaneous application of ultrasonic energy.

[0102] Figures 6A to 6C Another synchronized dual weld head configuration is shown in FIG, which is suitable for sealing parts with complex geometries, such as plastic or metal spouts for liquid bags, pillows, or containers. Here, the two transducers 102, 104 are positioned relative to the second contour weld head 608 and the first contour weld head 606 having an opening 612 ( Figure 6C ) to receive therein the part 332 to be sealed. The ends of the welding tips 606, 608 have a knurled surface 608b (at Figure 6B ) to clamp around a part 332 (which may be a circular nozzle, for example), which translates to a ribbed weld surface 608a that receives the circular (or oval) part 332. Another weld head 608 has the same weld surface, so that the weld heads are pressed against each other, the part 332 is held in place, and the evenly applied energy is evenly distributed around the part to produce a consistent weld. Contour weld heads 606, 608 can be shaped to match the contour of any part geometry, including circular, oval, or any irregular geometry.

[0103] exist Figure 8A and Figure 8B Another dual horn structure is schematically shown in FIG. The two horns 806, 808 are of the rotary type, and those familiar with ultrasonic welding technology will understand the rotary horn and how to drive the rotary horn, and the details of the rotary horn are irrelevant to the understanding of this configuration. An example of a configuration including a rotary horn and a fixed anvil is shown in U.S. Patent No. 10,479,025, issued on November 19, 2019, entitled "Apparatus for fabrication an elastic nonwoven material", the entire contents of which are incorporated herein by reference. Based on the concepts disclosed herein, it is proposed that Figure 8ATwo rotating horns 806, 808 are shown, wherein the two horns 806, 808 contact both sides of a part 810 having multiple layers 840a, 840b (although more than two are contemplated), such as a part having multiple layers of nonwoven material to be joined or sealed together, and the part passes between the two horns 806, 808 as the horns rotate at the same angular velocity ω1. As disclosed herein, the frequency and phase of the respective ultrasonic energies applied to the horns 806, 808 are synchronized to produce a high quality seal or joint of the layers 840a, 840b of the part 810 in one pass through the horns 806, 808. As the part 810 passes between the horns 806, 808, forces may be applied to the layers 840a, 840b of the part 810 between the horns 806, 808. For ease of illustration, Figure 8A and Figure 8B The physical separation between layers 840a, 840b is exaggerated in FIG to illustrate how layers 840a, 840b are connected together by dual rotating horns 806, 808 driven by respective transducers 102, 104. Each of the transducers 102, 104 is powered by a respective output of one or more ultrasonic generators, as described above, which generate ultrasonic energy outputs to both transducers 102, 104 that are synchronized in both frequency and phase. Thus, in this configuration, the angular velocity ω1 of the horns and the frequency and phase of the ultrasonic energy applied to each horn are synchronously matched.

[0104] The layers 840a, 840b of the part 810 are drawn between the two horns 806, 808, which are rotating at the same angular velocity as when ultrasonic energy having the same frequency and phase is simultaneously applied to both horns 806, 808. By simultaneously applying frequency and phase matched ultrasonic energy to the two horns 806, 808, the amplitude of the energy is reduced compared to a configuration having only one energized stack, which results in higher throughput (e.g., in excess of 2000 feet per minute) while expanding the process window.

[0105] Also disclosed herein is an ultrasonic welding method for sealing multiple layers of a part together (forming a to-be-sealed interface). The method includes moving a first welding surface of a first horn toward an opposing second welding surface of a second horn to close a gap between the first and second welding surfaces until the first and second welding surfaces contact a part, such as a part having different layers along a portion of the part to be sealed. In response to contacting the part, the method applies first ultrasonic energy, output by the first horn, and second ultrasonic energy, output by the second horn, to the portion of the part between the two horns, synchronizing the frequencies and phases of the first and second ultrasonic energies and simultaneously applying the first and second ultrasonic energies to both sides of the part, thereby sealing the layers together. The respective output tips of the first and second horns are arranged to point toward each other. Importantly, closing and retracting the horns only occurs once to seal the interface without causing any burns, visual artifacts, or leaving any air or liquid leaks along the interface. In contrast, conventional methods require multiple weld head movements (e.g., three or more) to create a seal, are time consuming, and increase the risk of burning portions of the interface or creating undesirable visual artifacts, particularly in thinner areas of the interface (e.g., when sealing a mountain top).

[0106] Aspects of the present disclosure can also be applied to so-called far-field welding, in which the area to be welded is located at a physical distance from the horn output or surface, where ultrasonic energy is transferred from the solid substrate to an area outside the horn. In many applications, the location of the joint relative to the horn contact area can be critical, as the ultrasonic energy must penetrate the material to reach the desired melting zone. Near-field and far-field welding refer to the distance over which the ultrasonic energy is transferred from the horn contact point to the joint interface. For example, when the distance between the horn output or surface and the joint interface to be welded is 1 / 4 inch (6 mm) or less, the weld is considered near-field. Conversely, when the distance is greater than 1 / 4 inch (6 mm), the weld is considered far-field. Whenever possible, welding near-field is always preferred. This is because far-field welding requires higher-than-normal amplitudes, longer weld times, and higher forces to achieve comparable near-field welds. Generally speaking, far-field welding is recommended only for amorphous resins, which transmit energy better than semi-crystalline resins. However, the dual horn configuration disclosed herein expands the application of far-field welding because energy is applied simultaneously from both sides of the interface.

[0107] The dual horn aspects disclosed herein may also be applied to ultrasonically assisted wire drawing processes or ultrasonically assisted metal forming processes. Conventional metal drawing or forming processes contemplate the use of a single ultrasonic energy source applied to a hard steel die, for example, as the wire or metal is pulled through the die. The pulling forces are very high, and eventually the die becomes dull and requires replacement. The present disclosure contemplates applying ultrasonic energy that is synchronized in frequency and phase to both sides of the die while the wire or metal is pulled through the die by an external pulling force. The energy creates vibrations in the die that cause the die to act as a lubricant, thereby reducing the force required to draw the wire through the die. The die would need to be replaced at longer intervals, thereby increasing the throughput of processes involving wire drawing or metal forming.

[0108] Figures 9A to 9E An example of an ultrasonic assisted metal forming process using synchronized ultrasonic energy is shown. For convenience, "ultrasonic welding system" as used herein includes systems such as Figures 9A to 9E Ultrasonic assisted metal forming processes are shown. Although these processes do not weld parts together in the traditional or conventional sense, they operate using the synchronized frequency principles disclosed herein and are encompassed within the umbrella of ultrasonic welding systems. Figure 9A An exemplary configuration of a wire drawing system 900 is shown having a die 902 having a plurality of ultrasonic welding stacks (including transducers and horns) 904a, 904b, 904c, 904d that apply ultrasonic energy at a frequency and phase synchronized with the respective portions of the die 902. In this example, the die 902 operates as a horn that mechanically oscillates back and forth in a vibratory motion in response to the ultrasonic energy imparted into the die by the transducers 904a, 904b, 904c, 904d. Wire drawing and metal forming systems are well known in the art, and configurations of wire drawing and metal forming systems are well known to those skilled in the art and are not reproduced here for ease of discussion. The basic configuration includes a die 902 of some kind ... Figure 1In the example shown, the wire 910 is formed such that when a wire having an initial gauge or thickness is drawn through the gap 915 in the die, typically by drawing, the gap 915 of the die 902 has a starting diameter that is larger than the ending diameter, so that the diameter of the wire 910 is reduced to the desired gauge or thickness (912) as it is drawn through the die 902. As the wire 910 is drawn through the gap 915 of the die 902, the wire 910 is pressed against the first part engaging surface 915 and the second part engaging surface 917 of the die 902. Here, the concept of the present invention is to apply energy to the die 902 (non-resonant parts in this ultrasonic embodiment) using synchronized (in frequency and in phase) ultrasonic welding stacks, causing the parts of the die 902 to mechanically vibrate, resulting in a number of benefits compared to conventional wire drawing techniques that do not use frequency synchronized ultrasonic energy. An example of a method for applying ultrasonic vibrations to a non-resonant part is disclosed in US Pat. No. 9,993,843, entitled “Adapter for Ultrasonic Transducer Assembly,” which is incorporated herein by reference in its entirety.

[0109] exist Figure 9A In the illustrated assembly 900, there are four ultrasonic welding stacks 904a, 904b, 904c, and 904d including transducers, which are arranged around the mold to apply energy to the mold 902 at the transducer locations. In actual applications, these ultrasonic welding stacks can be deployed in pairs (e.g., 904a and 904d, or 904b and 904c). In other words, although Figure 9AFour ultrasonic weld stacks are shown, but it is contemplated that a single pair of stacks, such as 904a and 904d, could be used instead. Again, in one embodiment, the energy is fully synchronized in frequency and phase, as shown in the example waveforms in the figure. In other embodiments, it may be advantageous to synchronize only the frequency, but with two or more different phases, among the four ultrasonic weld stacks 904a, 904b, 904c, and 904d. While the representative waveforms shown in the figure are shown as having the same frequency and phase as one another, it should be understood that the phases between any of the transducers may be different or asynchronous. The synchronized energy applied via transducers 904a, 904b, 904c, and 904d through the die 902 (operating as a non-resonant part) causes the die 902 to mechanically vibrate rapidly (at or near the frequency of the ultrasonic energy), thereby causing the wire to act as a lubricant as it is drawn through the gap 915 of the die 902. Compared to conventional techniques, the required pulling force is also less because the rapidly vibrating "lubricated" die 902 allows the wire 910 to be pulled through the die more quickly and with less force and without the use of liquid or wet lubricants. This type of wire drawing is referred to as dry wire drawing because no lubricant or liquid is used at the wire-die interface to facilitate the drawing process. The metal wire 910 drawn by this method advantageously has an excellent smooth surface finish with few or no defects, and results in faster drawing speeds, lower drawing forces, and reduces or eliminates the need for any external lubricant at the wire-die interface. The wire 910 can be made of copper, aluminum, or any other conductive metal or metal alloy, and can be solid or stranded.

[0110] Back to Figure 9AWhen viewing the figure, the direction of wire stretching is from left to right, with the thicker portion of wire 910 being stretched through the input portion of gap 915 of die 902 to produce a thinner portion of wire 912 to the right of the output portion of die 902. Four ultrasonic welding stacks 904a, 904b, 904c, and 904d are positioned around die 902. When these transducers apply ultrasonic energy through die 902, die 902 acts as a mechanical vibration horn. Top die 904a is positioned adjacent to the top surface of die 902, while bottom die 904d is positioned adjacent to the bottom surface of die 902. Top die 904a and bottom die 904d are arranged to direct their respective ultrasonic energies toward each other and toward wire 910 being drawn through die 902. This energy is synchronized in frequency and, optionally, in phase. In addition, two additional transducers 904b and 904c are positioned on the end faces of die 902, above and below the output portion of die 902. These transducers 904b, 904c direct their respective ultrasonic energies parallel to each other and in a direction opposite to the direction of travel of the wire 910 through the die 902. This creates a field of coordinated ultrasonic energy within the die 902 that all vibrate at the same frequency, which causes the surface interface between the die 902 and the wire 910 to mechanically vibrate rapidly and uniformly in multiple directions. Without synchronized frequencies, the vibrations within the die would be non-uniform, which would cause the wire to have undesirable surface artifacts as it is pulled through the die and / or experience different mechanical stresses or strains or non-uniform deformation along its diameter as it is pulled through the die, thereby causing one side of the wire to be pulled out at a different rate than the other side of the wire.

[0111] Figure 9B FIGURE 9 illustrates another ultrasonically assisted metal forming process 920 in which a metal part 930 undergoes a deep drawing process with the assistance of a die 922 and a punch 926. Three ultrasonic transducers 924a, 924b, and 924c are arranged on the die 922 and punch 926 to facilitate the deep drawing operation on the part 930. In this example, an ultrasonic stack 924c is arranged adjacent to the punch 926 and directs ultrasonic energy in the same direction as the punch moves to complete the deep drawing process on the part 930. Two other ultrasonic weld stacks 924a and 924b are arranged adjacent to opposing surfaces of the die 922 so that the energy of each of the ultrasonic weld stacks 924a and 924b is directed toward each other and toward the part 930 being punched through the die interface. The ultrasonic frequencies of the transducers 924a, 924b, and 924c are synchronized, and optionally, their phases may also be synchronized. Alternatively, the phase of the ultrasonic energy applied by transducer 924c through punch 926 may be out of phase with respect to the synchronous phase of the energy applied by transducers 924a, 924b to opposite sides of die 922. Part 930 is received in gap 925 of die 922, which is similar to Figure 9AThe die 902 shown in FIG. 1 operates as a non-resonant portion of the stack 924a, 924b. Die 922 has a first part-engaging surface 935 and a second part-engaging surface 937 that contact part 930 as it undergoes the deep drawing process. The synchronous vibration of die 922 causes the part to vibrate back and forth relative to the die at first and second part-engaging surfaces 935, 937 (as well as other part-engaging surfaces in contact with the die), primarily those surfaces that are subject to deformation or bending during the deep drawing process.

[0112] Extrusion-type ultrasonic assisted metal forming process 940 Figure 9C , where when a metal part 950 is squeezed through a gap 945 in a die 942, the metal part 950 is squeezed through the die 942 by a ram 946 which applies a pushing force to the metal part 950. Figure 9A In the assembly shown, four ultrasonic weld stacks 944a, 944b, 944c, 944d are arranged around the output portion of the die 942, and the ultrasonic energy output of the ultrasonic weld stacks 944a, 944b, 944c, 944d is synchronized in frequency and optionally in phase. The physical arrangement of the ultrasonic weld stacks 944a, 944b, 944c, 944d in this assembly 940 is similar to that of the Figure 9A . The arrows indicate the direction of the respective ultrasonic energies output from the transducers of the stacks 944a, 944b, 944c, 944d and provided through the die 942 as the part 950 is pressed through the die 942 by the impact force of the ram 946. At least four part-engaging surfaces 955a, 955b, 957a, 957b of the die 942 come into contact with respective surfaces of the part 950 as it undergoes the metal forming process.

[0113] Forging type ultrasonic assisted metal forming process 960 Figure 9D , where a metal part 970 is subjected to a compressive force by a mold 962. Four ultrasonic welding stacks 964a, 964b, 964c, 964d comprising transducers are arranged adjacent to portions of the mold 962, and the ultrasonic energy of the ultrasonic welding stacks 964a, 964b, 964c, 964d is synchronized in frequency and optionally in phase. The top transducer 964a is arranged adjacent to the top surface of the top of the mold 962 and directs its energy downward toward the part 970. The bottom transducer 964c is arranged adjacent to the bottom surface of the bottom of the mold 962 and directs its energy upward toward the part 970 and toward the top transducer 964a. Figure 9DAs shown, a first side transducer 964d is positioned adjacent to the left side of the bottom of die 962 and directs its energy into die 962 from left to right, as shown. A second side transducer 964b is positioned adjacent to the right side of the top of die 962 and directs its energy into die 962 from right to left, in the opposite direction from first side transducer 964d. Part 970 is positioned in gap 965 and contacts at least first part-engaging surface 975 and second part-engaging surface 977 of die 962. When ultrasonic energy is applied to the horn or die 962, the die again behaves like an ultrasonically non-resonant part / horn. This configuration produces a consistent and uniform vibration profile at the die-part interface, allowing for uniform compression at a faster rate than conventional metal forging processes.

[0114] Rolling ultrasonic assisted metal forming process 980 Figure 9E , wherein a part 990 is subjected to rolling forces by two rollers 982a and 982b. Part 990 passes through a gap 985 between rollers 982a and 982b in the direction of arrow A, thereby reducing its cross-sectional area. Part 992 contacts a first part-engaging surface 995 of top roller 982a and a second part-engaging surface 997 of bottom roller 982b. A first ultrasonic stack 984a is configured to abut top roller 982a, while a second ultrasonic stack 984b is configured to abut bottom roller 982b. Ultrasonic stacks 984a and 984b are positioned to output their respective ultrasonic energy in a direction B that is transverse or perpendicular to the direction of arrow A. This process 980 produces a smoother rolling operation without the use of external lubricants and does not produce artifacts on the surface of part 990 as it is pulled through rollers 982a and 982b.

[0115] Figure 10 Two example configurations of two packaging systems are shown, in which any of the ultrasonic welding systems disclosed herein may be incorporated. It will be readily understood by those skilled in the packaging arts that the machine may be oriented so that packages or pouches or bags or other containers filled with substances (food, liquids, powders, etc.) are formed in either a horizontal or vertical direction. A packaging system arranged horizontally is referred to as a horizontal form, fill and seal (HFFS) packaging system, and a packaging system arranged vertically is referred to as a vertical form, fill and seal (VFFS) packaging system. The implementations and embodiments disclosed herein may be oriented horizontally or vertically and are equally applicable to both HFFS and VFFS packaging systems. In Figure 10In the left figure of FIG, an example VFFS packaging system 1000a is shown. In the right figure, an example HFFS packaging system 1000b is shown. It is reiterated that this shows one example configuration of many configurations, and those familiar with packaging technology will understand that other configurations will be different. Figure 10 These examples are provided for ease of discussion to illustrate that the ultrasonic welding systems herein can be incorporated into packaging system processes to seal and optionally cut parts into individual parts that are filled with a substance.

[0116] An exemplary VFFS packaging system 1000a includes a roll of film 1002 that is conveyed in a vertical direction by a roller system toward a forming tube 1006, with product 1004 or any other substance filling a pouch or bag or container formed from the film before entering a sealing unit 1012 that optionally cuts the film to separate the parts and thereby separate them from the roll of film 1002. Any of the ultrasonic welding systems disclosed herein, particularly but not limited to those discussed in the subsequent figures, may be incorporated as a Figure 10 A sealing unit 1012 is shown in the VFFS packaging system shown.

[0117] Exemplary HFFS packaging system 1000b includes a roll of film 1020 that passes through a series of rollers 1022 toward a forming box 1030, where the film is folded to form pouches or other containers to hold a product or substance 1026 that is conveyed to forming box 1030 by a belt conveyor 1024. The product or substance 1026 enters forming box 1030 to be loosely contained therein until its top can be sealed by fin sealing rollers 1034. The pouches 1048 or packages to be formed enter end sealer and cutter assembly 1040, where the sides of the pouches are sealed and cut to singulate the packages or pouches 1050 before being conveyed to a discharge conveyor 1042. In order to singulate the packages 1048 to be formed on both open sides, the sealer and cutter assembly 1040 needs to make two passes as the packages 1048 to be formed pass through assembly 1040. For example, assembly 1040 is rotatable and is part of any of the ultrasonic welding systems disclosed herein that can be replaced. The ultrasonic welding systems herein overcome many of the drawbacks present in conventional sealer and cutter assemblies, including requiring only a single pass, resulting in higher quality hermetic seals, and increased production volume of singulated packages 1050.

[0118] Figure 11A A perspective view of an ultrasonically assisted "cut and seal" assembly 1100 is shown having synchronized ultrasonic energy applied to a horn 1110 (e.g., Figure 121102 having multiple layers between the horn 1110 and the anvils 1114a, 1114b. This configuration utilizes the "scrubbing" action described herein and is particularly effective in sealing two or more films in the roll 1102 together. Figure 11A 、 Figure 11B 、 Figure 11C 、 Figure 11D 、 Figure 11E 、 Figure 11F and Figure 12 , Figure 11A 、 Figure 11B 、 Figure 11C 、 Figure 11D 、 Figure 11E 、 Figure 11F and Figure 12 The diagram shows how the horn 1110, transducers 1112a, 1112b, and anvils 1114a, 1114b cooperate to apply ultrasonic energy to the roll 1102 to apply a scrubbing action, while simultaneously sealing the roll in the portion between two adjacent parts 1104 of the roll 1102 at two locations, while also optionally performing a cutting operation to cut the area between the two sealed portions. Similarly, while these exemplary configurations are shown in a horizontal orientation suitable for a HFFS packaging system, these examples are equally applicable to a VFFS packaging system and can be oriented vertically. Those familiar with thin film packaging systems will readily appreciate that orientation is immaterial to the implementation of the novel and inventive concepts herein.

[0119] In this example, a plurality of pouches or bags 1104d, 1104e, 1104f are formed from a roll 1102, formed between two layers of film or other material 1104a, 1104b, and need to be sealed, such as after they have been filled with contents (e.g., liquid, food, powder, etc.). So-called pillow pouches or bags are well known in the packaging industry, and traditionally, pillow pouches or bags are formed along a continuous roll, then heat-sealed, and then subsequently cut to singulate the pouches from the roll into individual items. Only those configurations and apparatus relevant to practicing the claimed invention are described herein, as it is assumed that those skilled in the packaging arts, and particularly those skilled in the art of pillow pouch packaging, will be very familiar with the machinery used to fill, seal, and cut the roll into individual pouches.

[0120] The present disclosure improves upon the art of pillow pouch packaging by introducing at least two ultrasonic transducers 1112a, 1112b that apply frequency and phase synchronized ultrasonic energy to the horn 1110. An example of such a configuration may be found at Figure 11A11. Transducers 1112a, 1112b are positioned relative to horn 1110 such that they direct their respective ultrasonic energy toward each other into the horn in a direction transverse to the direction of travel of web 1102 (e.g., from left to right as indicated by arrow X). As web 1102 travels in the X direction between anvils 1114a, 1114b and horn 1110, anvils 1114a, 1114b or horn 1110, or both, move toward each other to sandwich web portion 1102a therebetween. Figure 11C A portion 1102a of the roll is shown almost ready to be clamped between the horn 1110 and the anvils 1114a, 1114b. Figure 11D In FIG. 1 , it can be seen that the portion 1102a of the roll is clamped in a U-shape between the welding head 1110 and the anvils 1114a, 1114b. Figure 11D As shown, by moving the anvils 1114a, 1114b in the directions of arrows A and B, the anvils 1114a, 1114b are clamped together, and the horn 1110 is rapidly vibrated up and down in the bidirectional directions indicated by arrows C. This rapid up and down mechanical motion of the horn is caused by the synchronized ultrasonic energy applied by the transducers 1112a, 1112b (see Figure 12 The FEA analysis in FIG. 10 ) causes a first welding head interface 11120a and a second welding head interface 1120b (in FIG. Figure 11E 1102) performs a "scrubbing" action on the portion of the web 1110 trapped between the interfaces 1120a, 1120b and the respective anvils 1114a, 1114b, thereby simultaneously creating two seals in a single pass (e.g., on the back of the leading pouch 1104d on the web 1102 and in front of the next pouch 1102c). The advancing web 1102 need only pause for application of ultrasonic energy before resuming sealing the next advancing pouch 1104c. This rapid motion simultaneously creates uniform seals along the portion 1102a of the web 1102 at two locations between the layers of the web 1102. Figure 11E As shown, a gap or slot 1130b is formed in the end 1122 of the horn 1110 which can accommodate an optional blade 1116 having a sharp tip 1124 which can cut a portion 1140 of the roll 1102 while two seals are formed at the horn interface or part engaging surfaces 1120a, 1120b. Figure 11F1102 ). This dual action is referred to as "cutting and sealing" because the two operations occur simultaneously, thereby increasing roll throughput and singulation or individualization of the pouches or bags. The portion between the two seals is referred to as the inner sealing gap 1102a. Anvil 1114a has a surface 1123 that presses against portion 1104 of roll 1102 adjacent to first part-engaging surface 1120a of horn 1110. Anvil 1114b also has a surface 1125 that presses against portion 1104 of roll 1102 adjacent to second part-engaging surface 1120b of horn 1110.

[0121] Figure 12 This is a color-coded illustration of a finite element analysis (FEA) of the horn 1110 as dual transducers 1112a and 1112b transmit synchronized ultrasonic energy into the horn 1110. The stress and strain in the metal of the horn 1110 causes it to rapidly expand and contract, creating a scrubbing action that allows the interfaces 1120a and 1120b to move back and forth rapidly. This friction generates uniform heat energy, which rapidly creates an airtight seal at the interfaces 1120a and 1120b at two locations on the coil simultaneously. For ease of illustration, the deformation of the metal is exaggerated in this model.

[0122] Figure 13A is a perspective view of an ultrasonically assisted “cut and seal” assembly 1300 having dual ultrasonic transducers 1312a, 1312b applying synchronized ultrasonic energy to a resonant horn 1310 that captures a roll, such as roll 1102, having multiple layers between the horn 1310 and anvil 1314. Figure 14A is a perspective view of an ultrasonically assisted "cut and seal" assembly 1400 having dual ultrasonic transducers 1412a, 1412b applying synchronized ultrasonic energy to a resonant horn 1410 that captures a roll, such as roll 1102, having multiple layers between the horn 1410 and anvil 1414. As shown by comparison Figure 13A and Figure 14A It can be seen that, Figure 13A The resonance horn 1310 in FIG. 1 has short grooves 1311 and 1313 formed along the end edges of the horn 1310. Figure 13C As shown, a resonant horn with short slots near the output face has nodes (areas of minimal motion) near the inside of the slots and anti-nodes (areas of maximum motion) on the outer surface of the horn. This motion produces Figure 13C Back and forth scrubbing motion as shown. Figure 14AThe resonant horn 1410 in FIG. 1 has an elongated slot 1411 formed along the body of the horn 1410, but the other components 1300 and 1400 are identical. An optional blade 1316 is shown in the anvil 1315, which can be used to perform a cutting operation in the space between adjacent sealing interfaces, which space is defined by the gap 1322 between the fingers of the horn 1310 and the anvil 1314, as shown in FIG. Figure 13B shown. Figure 13C Two FEA images of the horn 1310 are shown as out-of-phase ultrasonic energy is applied to the body of the horn 1310 via dual transducers 1312a, 1312b. While the deformation or displacement of the horn 1310 has been exaggerated for ease of illustration, the images illustrate how the horn 1310 rapidly moves back and forth in the directions of arrows A and B to create a scrubbing action on its end surface. When pressed against anvil 1314, the combination of the scrubbing action, which generates heat contributed by the ultrasonic energy, and the mechanical force applied to the membrane between the horn 1310 and anvil 1314, creates a hermetic seal at the interface of the membrane being scrubbed. This seal can be created by actuating the horn in and out, or by continuously rotating the horn so that it contacts the membrane twice per rotation.

[0123] Figure 14A Shown Figure 13A Two FEA images of a resonant horn 1410 are shown. Again, the distortion is exaggerated to illustrate the direction of motion or distortion of the horn 1410 as out-of-phase ultrasonic energy passes through the body of the horn 1410 via dual transducers 1412a, 1412b, which deliver ultrasonic energy having synchronized frequencies toward each other into the horn 1410. Grooves 1411 are slightly deformed to allow for mechanical motion of the horn 1410, referred to herein as scrubbing, on the end faces of the horn 1410 before they are pressed against anvil 1414. The horn 1410 can be driven in and out or continuously rotated so that it contacts the membrane twice per rotation. Figure 14B The longer one creates a node (the area with the least activity) and passes through the slot. Figure 14B As shown, anti-nodes (areas of maximum motion) appear on the output face of the horn, creating a back-and-forth scrubbing action.

[0124] FIG15A is a top or bottom view of a prior art cutting blade 1502 sandwiched between two ultrasonically welded stack assemblies 1512a, 1512b. FIG15B is a side view of the cutting blade 1502 and ultrasonically welded stack assemblies 1512a, 1512b shown in FIG15A. The cutting blade 1502 has two cutting edges 1524a, 1524b having a sharpness configured to cut through a substance such as a block of food. The type of substance is not important to the present disclosure. A disadvantage of this prior art approach is that the cutting blade 1502 is subject to multiple nodes (areas of minimal motion activity) along the axis of the blade 1502 (and the cutting edges). As a result, there will be very poor cutting at and near these nodes. Next, in Figure 16A 、 Figure 16B 、 Figures 16C to 18A 、 Figure 18B 、 Figure 18C The embodiment shown in Figure 15A eliminates these undesirable nodes along the cutting edge, and guarantees the consistent amplitude along the cutting edge of the cutting blade.In addition, the cutting blade 1502 shown in Figure 15 A and Figure 15B is not suitable for cutting the material whose thickness is equal to or greater than the height of the cutting blade 1502.

[0125] Figure 16A 1 is a perspective view of a rotatable resonant cutting blade 1602 of a synchronized cutting assembly 1600 sandwiched between two ultrasonic welding stack assemblies 1612a, 1612b, the respective transducers of which output synchronized ultrasonic energy (frequency and phase) into the cutting blade 1602, which operates like a resonant horn. Figure 16B yes Figure 16A A side view of the cutting blade assembly 1600 is shown. 16a. Figure 16C yes Figure 16A An end view of the cutting blade assembly 1600 is shown. In this example, the cutting blade 1602 has a Figure 11A The long slot shown in the welding head 1110 of FIG. 1602 can be configured to rotate about an axis passing through the stack 1612a, 1612b and the cutting blade 1602. An example of such rotation is shown in FIG. 17A to 17CAs the cutting blade 1602 cuts through the material, the two stacking section assemblies 1612a, 1612b simultaneously introduce synchronized ultrasonic energy into the cutting blade 1602, causing the blade 1602 to vibrate in a push-pull manner toward one stacking section 1612a and away from the other stacking section 1612b, and in a push-pull manner away from one stacking section 1612a and toward the other stacking section 1612b. In addition to producing a consistent, uniform amplitude along the cutting edges 1624a, 1624b of the cutting blade 1602, the blade 1602 has the additional advantage of being able to cut through material with a thickness exceeding the height of the blade 1602. An example of this embodiment is shown in FIG. Figure 17A 、 Figure 17B and Figure 17C Shown in.

[0126] Figure 17A yes Figure 16A A perspective view of a rotatable cutting blade assembly 1600 is shown cutting through a thick block of matter 1700, such as food. Figure 17B yes Figure 17A An end view of the rotatable cutting blade assembly 1600 is shown, wherein the dual ultrasonic weld stack assemblies 1612a, 1612b are visible. Figure 17C yes Figure 17A A side view of the rotatable cutting blade assembly 1600 is shown. The entire cutting blade assembly 1600, along with the blade stacks 1612a, 1612b, can be configured to rotate about an axis passing through the blade stacks 1612a, 1612b and the blade 1602, which facilitates cutting through thick materials, even materials having a thickness exceeding the height of the blade 1602. As the blade 1602 slices or cuts through the material 1700 due to the push-pull vibrations exerted simultaneously by the synchronized energy stacks 1612a, 1612b, the blade 1602 can rotate slightly to ensure that the cut is straight and to accommodate the non-flat profile of the blade 1602.

[0127] Figure 18A 1 is a functional diagram of a cutting blade 1602 configured to cut through a substance 1800 having a thickness T1 from either a top or bottom cutting blade surface 1624a, 1624b. In this example, T1 is less than the height of the blade 1602, and either cutting surface 1624a, 1624b of the cutting blade 1602 can cut the substance 1800 while cutting the substance 1800 into portions 1850a, 1850b, 1850c, and so on.

[0128] Figure 18Bis a functional illustration of a cutting blade 1602 configured to cut through a substance 1802 having a thickness T2 >> T1 and also greater than the height of the cutting blade 1602. This embodiment illustrates that the synchronized ultrasonic stacks herein can be utilized to apply synchronized ultrasonic energy to a cutting blade having a height less than the thickness of the substance being cut to produce segmented pieces of substance 1852a, 1852b, 1852c, etc.

[0129] Figure 18C 1 is a functional diagram illustrating how the cutting blade 1602 can be rotated to cut a mass of material 1804 at least twice per rotation of the cutting blade 1602 to produce segmented masses of material 1804a, 1804b, 1804c. During a first half of the rotation, one of the cutting blade edges 1624a cuts through the object 1804, and during a second half of the rotation, the other cutting blade edge 1624b cuts through the object 1804. The thickness of the material 1804 is less than half the height of the cutting blade 1602 to ensure that the rotation of the blade 1602 does not interfere with the passing material 1804 moving relative to the blade 1602.

[0130] While some materials suitable for sealing or welding using the simultaneous dual-horn ultrasonic energy application disclosed herein have been described herein, including plastics and nonwoven films, the present disclosure contemplates sealing or welding together other types of the same or different materials, including pouches made of polyester printed onto aluminum and then laminated to polyethylene, metals including aluminum, metal foils, fabrics, films, polyethylene-coated fiberboard, or liquid paperboard, among others.

[0131] Advantages of the systems and methods disclosed herein include:

[0132] Increased process speed: Compared to conventional ultrasonic welding techniques that require multiple cycles and applications of ultrasonic energy, the systems and methods herein require only one cycle to create a hermetic seal for a variety of packages, geometries, and materials.

[0133] Sealing through same or dissimilar materials: A hermetic seal is formed by a single application of synchronized ultrasonic energy imparted by two opposing horns, regardless of the uniformity of the material or its thickness.

[0134] Consistent, repeatable welding results with a wider process window: Because both weld heads apply the same ultrasonic energy (same frequency and phase) simultaneously, this effectively doubles the amplitude of the energy, enabling a wider process window than conventional techniques.

[0135] In the production area, the process is greener (ultrasonic welding requires much less energy than heat sealing techniques): compared to heat sealing techniques that require the application of heat energy to create a seal, ultrasonic energy uses less energy by comparison, creating a seal in seconds, such as 0.35 seconds or even faster.

[0136] Enables the use of new materials, including bioplastics and materials with poor welding compatibility: The dual horn arrangement, synchronized with frequency and phase, and optionally combined with a scrubbing action generated by the horn vibrations, significantly expands the available combinations of materials, interfaces and geometries that can be used to produce consistently high quality seals or welds.

[0137] Reduced waste and delays; improved yields: Conventional technologies produce inconsistent seals, sometimes with tiny leaks, or can create burns or other visual artifacts, requiring parts to be discarded, reducing overall yield.

[0138] Narrower seals result in material savings: the interface or area to be sealed can be considerably smaller than with conventional techniques, allowing less overall material to be used. When sealing or welding millions of parts, a small reduction in material per part can result in a significant reduction in overall material.

[0139] Eliminate channel leaks: Conventional techniques can create tiny leaks that can pose a risk of air, pathogens, and / or mold, but the system and method of the present invention eliminates leaks without creating any visual artifacts and without causing burns at the interface of the seal.

[0140] Reducing the complexity of the manufacturing process, such as welding a spout to a pouch, can be accomplished in a single pass or cycle using this technology. By comparison, the same spout-to-pouch weld currently requires three passes or cycles using conventional ultrasonic welding technology.

[0141] Eliminates liquid or product contamination in the joint area due to ultrasonic energy (vibration) from the ultrasonically welded stack. Also eliminates liquid content between two joints on vertical or horizontal packaging machines where liquid is undesirable (for example, in brick carton assembly lines).

Claims

1. An ultrasonic welding system for sealing together multiple layers of a part, the system comprising: a first ultrasonic weld stack and a second ultrasonic weld stack, the first ultrasonic weld stack including a first horn and the second ultrasonic weld stack including a second horn, the first horn having a first weld surface and the second horn having a second weld surface opposite the first weld surface to define a gap between the first weld surface and the second weld surface, wherein the gap is configured to receive a part therein to be sealed along a portion of the part; an actuator assembly operably coupled to the first ultrasonic weld stack and the second ultrasonic weld stack and configured to move the first weld surface relative to the second weld surface; One or more controllers operably coupled to the first ultrasonic welding stack, the second ultrasonic welding stack, and the actuator assembly, the one or more controllers operably configured to: The actuator assembly pushes the first welding surface of the first welding horn and the second welding surface of the second welding horn toward each other until contact is made with the part, and thereby applies a first ultrasonic energy to the part via the first welding horn and a second ultrasonic energy to the part via the second welding horn, such that the frequency and phase of the first ultrasonic energy and the second ultrasonic energy are synchronized when the first ultrasonic energy and the second ultrasonic energy are simultaneously applied to both sides of the part, thereby sealing the part along the portion.

2. The system of claim 1, wherein: The frequency is between 15 kHz and 70 kHz.

3. The system of claim 1, wherein: The part is a gable top having a different number of layers arranged across a longitudinal direction of the gable top.

4. The system of claim 1, wherein: The part is a gabled top having a different number of layers arranged across a direction transverse to a longitudinal direction of the gabled top.

5. The system of claim 1, wherein: The amplitude of the first ultrasonic energy is different from the amplitude of the second ultrasonic energy.

6. The system of claim 1 , further comprising a first generator for generating the first ultrasonic energy and a second generator for generating the second ultrasonic energy, wherein The first generator is designated as a master generator, which automatically locks to feedback from the first ultrasonic weld stack using a phase locked loop and instructs the second generator, acting as a slave generator, to match its own phase and frequency to those of the first generator.

7. The system of claim 1, wherein: The parts are made from materials including polymer films, thermoplastics, nonwovens, foils, or metals.

8. The system of claim 1, wherein: The part is a pillow-shaped package having an end portion with a different number of layers arranged across the longitudinal direction of the end portion.

9. The system of claim 1, wherein: The part comprises different numbers of layers along the portion of the part to be sealed including: a first number of layers in a first portion of the part; and a second number of layers in a second portion of the part, the first number being different from the second number.

10. The system of claim 1, wherein: The part in question is the spout to be sealed to the pouch.

11. The system of claim 1, wherein: The first horn is a rotary horn and the second horn is a rotary horn, and the controller is further configured to rotate the first horn and the second horn at the same rotational speed while applying the synchronized first and second ultrasonic energies to the part.

12. The system of claim 6, wherein: The first generator includes a first output operatively connected to a first transducer and a second output operatively connected to a second transducer, the first transducer operatively connected to the first welding head and the second transducer operatively connected to the second welding head.

13. The system of claim 7, wherein: The area of the parts to be joined by remote field welding is at least 1 / 4 inch or 6 mm away from the first welding surface of the first welding head or the second welding surface of the second welding head.

14. A method of ultrasonic welding for sealing together multiple layers of a part, the method comprising the steps of: moving a first welding surface of a first welding head toward an opposing second welding surface of a second welding head to close a gap between the first welding surface and the second welding surface until the first welding surface and the second welding surface contact the part to be sealed along a portion of the part to be sealed; In response to contacting the part to be sealed, first ultrasonic energy is applied to the part to be sealed by the first welding head, and second ultrasonic energy is applied to the part to be sealed by the second welding head, so that the frequency and phase of the first ultrasonic energy and the second ultrasonic energy are synchronized when the first ultrasonic energy and the second ultrasonic energy are simultaneously applied to both sides of the part to be sealed, thereby sealing the part to be sealed along the portion, and the first welding head and the second welding head are arranged to point at each other.

15. The method of claim 14, further comprising retracting the first horn relative to the second horn to release the part in response to sealing the layers together.

16. The method of claim 14, wherein: The frequency is between 15 kHz and 70 kHz.

17. The method of claim 16, wherein: The movement is caused by a rotational movement of the first welding head rotating at the same speed as the rotational movement of the second welding head.

18. The method of claim 14, wherein: The amplitude of the first ultrasonic energy is different from the amplitude of the second ultrasonic energy.

19. A packaging device having at least one seal applied by the method of claim 14.

20. The packaging device according to claim 19, wherein The packaging device is a pillow-shaped package.

21. An ultrasonic welding system or metal forming system having a plurality of synchronized ultrasonic transducers, comprising: an ultrasonic transducer assembly comprising a horn, a first transducer, and a second transducer, the first transducer and the second transducer being arranged to transmit ultrasonic energy into the horn, the horn having a first part-engaging surface; a gap configured to receive a part therein to receive ultrasonic energy from the first transducer and the second transducer at an interface through the horn; an actuator assembly operably coupled to the ultrasonic transducer assembly and configured to move the part relative to the gap; one or more controllers operably coupled to the ultrasonic transducer assembly and the actuator assembly, the one or more controllers operably configured to: The actuator assembly is caused to push the part toward the gap until the part is pressed against the first part engagement surface, thereby applying first ultrasonic energy to the part through the horn via the first transducer and applying second ultrasonic energy to the part through the horn via the second transducer, such that the frequency and phase of the first ultrasonic energy and the second ultrasonic energy are synchronized when the first ultrasonic energy and the second ultrasonic energy are applied to the part.

22. The system of claim 21, wherein: When the first ultrasonic energy and the second ultrasonic energy are applied to the horn through the first transducer and the second transducer, the first part engaging surface of the horn vibrates back and forth.

23. The system of claim 22, wherein: Vibration of the first part engagement surface causes deformation of the part as the part moves relative to the gap.

24. The system of claim 23, wherein: The deformation is a change in the metallic structure of the part, the part being made of metal, or wherein the deformation is a sealing of multiple layers of the part to form a seal.

25. The system of claim 21, wherein: The horn has a second part engaging surface, the system further includes an anvil having a first surface and a second surface, and the one or more controllers are configured to move the first surface of the anvil and the first part engaging surface of the horn toward each other, and to move the second surface of the anvil and the second part engaging surface toward each other, thereby simultaneously generating a first seal and a second seal when the first ultrasonic energy and the second ultrasonic energy are transmitted to the horn through the first transducer and the second transducer.

26. The system of claim 25, further comprising a blade disposed between the first surface and the second surface of the anvil relative to the anvil, the one or more controllers being configured to actuate the blade to simultaneously cut the part along a portion between the first seal and the second seal when or after the first seal and the second seal are generated.

27. The system of claim 25, wherein: When the first ultrasonic energy and the second ultrasonic energy are applied to the welding head through the first transducer and the second transducer, the first part engaging surface and the second part engaging surface of the welding head vibrate back and forth, and wherein the direction of motion of the vibration of the first part engaging surface and the second part engaging surface is orthogonal to the direction of motion of the part, and wherein the phase of the first ultrasonic energy is 180 degrees out of phase with the phase of the second ultrasonic energy.

28. The system of claim 22, wherein: The vibration direction of the welding head is transverse to the movement direction of the part relative to the gap.

29. The system of claim 21, wherein: The welding head has a second part engaging surface coplanar with the first part engaging surface, and the system also includes an anvil having a first surface and a second surface coplanar with the first surface of the anvil. The one or more controllers are configured to move the welding head and the anvil toward each other so as to simultaneously generate a first seal portion and a second seal portion separated by an inner sealing gap when the first ultrasonic energy and the second ultrasonic energy are applied to the welding head through the first transducer and the second transducer.

30. The system of claim 29 further comprises a blade disposed between the first surface and the second surface of the anvil relative to the anvil, the one or more controllers being configured to actuate the blade while or after the first and second sealing portions are generated, thereby simultaneously cutting the part in the inner sealing gap.

31. The system of claim 21, wherein: The horn is a resonant horn.

32. The system of claim 21, wherein: The part is a wire stretched through a die using the ultrasonic welding system of claim 21.

33. The system of claim 21, wherein: The horn includes a cutting blade, and the first part engaging surface is a cutting edge, the cutting blade being configured to vibrate back and forth when the first ultrasonic energy and the second ultrasonic energy are applied to the cutting edge via the first transducer and the second transducer.

34. The system of claim 33, wherein: The height of the cutting blade is less than the thickness of the part through which the cutting blade cuts.

35. A method of using synchronized ultrasonic transducers to vibrate a horn relative to a part contacting the horn, the method comprising the steps of: receiving a part in a gap defined at least in part by a horn of an ultrasonic transducer assembly, the ultrasonic transducer assembly comprising the horn and first and second transducers, each of the first and second transducers being arranged to transmit ultrasonic energy into the horn, the horn having a first part-engaging surface; moving the part toward the gap via an actuator assembly operably coupled to the ultrasonic transducer assembly until the part contacts the first part engagement surface; In response to the part contacting the first part engaging surface, first ultrasonic energy is applied to the part through the horn via the first transducer, and second ultrasonic energy is simultaneously applied to the part through the horn via the second transducer, such that the frequencies and phases of the first and second ultrasonic energies are synchronized when applying the first and second ultrasonic energies to the part.

36. The method of claim 35, wherein: When the first ultrasonic energy and the second ultrasonic energy are applied to the horn through the first transducer and the second transducer, the first part engaging surface of the horn vibrates back and forth.

37. The method of claim 36, wherein: Vibration of the first part engagement surface causes deformation of the part as the part moves relative to the gap.

38. The method of claim 37, wherein: The deformation is a change in the metallic structure of the part, the part being made of metal, or wherein the deformation is a sealing of multiple layers of the part to form a seal.

39. The method of claim 35, wherein: The welding head has a second part engaging surface, and the method further comprises the steps of: The first surface of the anvil and the first part engaging surface of the horn are moved toward each other, and the second surface of the anvil and the second part engaging surface of the horn are moved toward each other, thereby simultaneously generating a first seal and a second seal when the first ultrasonic energy and the second ultrasonic energy are applied to the horn through the first transducer and the second transducer.

40. The method of claim 39, further comprising the steps of: In response to simultaneously forming the first and second seals, a blade disposed relative to the anvil between the first and second surfaces of the anvil is actuated to cut the part along a portion between the first and second seals.

41. The method of claim 35, further comprising the steps of: When the first ultrasonic energy and the second ultrasonic energy are applied to the horn through the first transducer and the second transducer, the horn and the anvil are moved toward each other, thereby simultaneously generating a first seal portion and a second seal portion separated by an inner sealing gap, and the horn has a second part engaging surface that is coplanar with the first part engaging surface.

42. The method of claim 41 , further comprising the steps of: In response to simultaneously creating the first and second seals, a blade is actuated to cut the part at the inner seal gap, the blade being disposed relative to the anvil between a first surface and a second surface of the anvil.

43. The method of claim 35, wherein: The first part engaging surface is a cutting blade configured to vibrate back and forth when the first ultrasonic energy and the second ultrasonic energy are applied to the cutting blade via the first transducer and the second transducer.

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