Abstract: An ultrasonic welding system includes a motion control system that is coupled to and that causes controlled movement of an ultrasonic welding stack, in accordance with control inputs that are based on one or more control signals that are received from one or more sensors. The motion control system initiates a welding operation, subsequent to which an initial motion delay occurs until a predetermined condition is satisfied. Subsequently, in response to the predetermined condition being satisfied, the ultrasonic welding stack is caused to move in accordance with a weld profile. Subsequently, in response to an occurrence of a predetermined delay initiating condition, the ultrasonic welding stack is caused to stop motion and to maintain a stationary position. Subsequently, in response to an occurrence of a predetermined delay terminating condition, motion of the ultrasonic welding stack is resumed in accordance with the weld profile.

Abstract: A vibration welding system and method having an operating vibration frequency of 260 Hz or higher. A pressing action between two workpieces is effected by directly controlling, with a control system and a sensor, the relative positions of the workpieces during some or all of the weld cycle, or by controlling the speed between the workpieces during some phase of the weld cycle and controlling the force between the workpieces during other phases. An external control device can be coupled to a control system, to produce an input signal to adjust the speed of relative motion between the workpieces, the force therebetween, or both speed and force based on the input signal.

Abstract: An ultrasonic welding system includes an ultrasonic welding stack that is movable to initiated a welding operation. A plurality of sensors measure respective control variables and output control signals corresponding, respectively, to the control variables. A motion control system is coupled to and causes controlled movement of the welding stack, including initiating the welding operation. The motion control system determines, based on the control signals, control inputs such that any motion of the welding stack, subsequent to the initiating, is initially delayed until the control signals satisfy a predetermined condition. In response to the predetermined condition being satisfied, the motion control system causes the welding stack to move in accordance with a weld profile.

Abstract: An ultrasonic welding system includes a controller, an electrically powered linear actuator driving a movable element to which an ultrasonic welding stack is mounted to move linearly and apply a controlled force and/or speed to a workpiece. A sensor measures a control variable and outputs to the controller a signal corresponding thereto. Based on this signal, the controller causes the linear actuator movable element to apply through the ultrasonic welding stack a predetermined positive initial force at an initiation of a welding operation and to limit a linear displacement of the ultrasonic welding stack to a predetermined initial displacement until the dynamic signal output from the sensor indicates that a sensed variable satisfies a predetermined condition. Based on the signal relating to the satisfied predetermined condition, the controller moves the ultrasonic welding stack in accord with a default weld profile or a weld profile selected from available weld profiles.

Abstract: A vibration welding system has a pair of electromagnets coupled to a first workpiece support for effecting reciprocating movement of the first workpiece support relative to a second workpiece support, and an electrical drive system coupled to the electromagnets for successively energizing and de-energizing the electromagnets out of phase with each other to effect the reciprocating movement of the first workpiece support. The drive system includes a source of DC current; multiple controllable electronic switching devices for controllably coupling the source to, and de-coupling the source from, each of the electromagnets; current sensors coupled to the electromagnets and producing signals representing the currents supplied to the electromagnets; and control circuitry coupled to the electronic switching devices and receiving the signals produced by the current sensors for turning the switching devices on and off to control the energizing and de-energizing of the electromagnets.

Abstract: A vibration welding system has a pair of electromagnets coupled to a first workpiece support for effecting reciprocating movement of the first workpiece support relative to a second workpiece support, and an electrical drive system coupled to the electromagnets for successively energizing and de-energizing the electromagnets out of phase with each other to effect the reciprocating movement of the first workpiece support. The drive system includes a source of DC current; multiple controllable electronic switching devices for controllably coupling the source to, and de-coupling the source from, each of the electromagnets; current sensors coupled to the electromagnets and producing signals representing the currents supplied to the electromagnets; and control circuitry coupled to the electronic switching devices and receiving the signals produced by the current sensors for turning the switching devices on and off to control the energizing and de-energizing of the electromagnets.

Abstract: A vibration welding system has a pair of electromagnets coupled to a first workpiece support for effecting reciprocating movement of the first workpiece support relative to a second workpiece support, and an electrical drive system coupled to the electromagnets for successively energizing and de-energizing the electromagnets out of phase with each other to effect the reciprocating movement of the first workpiece support.

Abstract: An ultrasonic welding method includes pressing an ultrasonic welding stack mounted for linear movement against a first workpiece using an electrical servo motor, applying a predetermined initial load to the first workpiece, and initiating a weld, comprising outputting energy from the ultrasonic welding stack to the first workpiece. The method includes sensing, with at least one sensor, a control variable, outputting a signal corresponding to the sensed control variable to a controller, simultaneously outputting energy from the ultrasonic welding stack to the first workpiece and maintaining a weld distance at or near zero until the signal corresponding to the sensed control variable satisfies a predetermined condition, and applying a controlled force, speed, or a combination thereof to said first workpiece with an electrically powered linear actuator to urge the first workpiece against a second workpiece to which the first workpiece is to be joined following satisfaction of the predetermined condition.

Abstract: A vibration welding system has a pair of electromagnets coupled to a first workpiece support for effecting reciprocating movement of the first workpiece support relative to a second workpiece support, and an electrical drive system coupled to the electromagnets for successively energizing and de-energizing the electromagnets out of phase with each other to effect the reciprocating movement of the first workpiece support.

Abstract: An ultrasonic welding method includes the acts of pressing an ultrasonic welding stack mounted for linear movement against a first workpiece using an electrical servo motor, applying a predetermined initial load to the first workpiece, and initiating a weld, the initiating of the weld comprising outputting energy from the ultrasonic welding stack to the first workpiece.

Abstract: An ultrasonic welding system includes an ultrasonic welding stack mounted for linear movement and for applying a controlled force, speed, or a combination of force and speed to a first workpiece to press the first workpiece against a second workpiece to which the first workpiece is to be joined, and an electrically powered linear actuator coupled to the ultrasonic welding stack for moving the stack while applying a controlled force, speed, or a combination of force and speed to said stack, the actuator including an electrical servo motor producing rotational mechanical motion and an integrated converter for converting the rotational motion into linear motion. In one specific implementation, a controller is coupled to the linear actuator for controlling the force applied by said actuator to the ultrasonic welding stack, and a sensor is coupled to the servo motor for producing a signal related to the torque produced by the servo motor and supplying that signal to the controller.

Abstract: An ultrasonic welding method includes the acts of pressing an ultrasonic welding stack mounted for linear movement against a first workpiece using an electrical servo motor, applying a predetermined initial load to the first workpiece, and initiating a weld, the initiating of the weld comprising outputting energy from the ultrasonic welding stack to the first workpiece.

Abstract: An ultrasonic generator comprising an input module for receiving a power signal. An output module for outputting an ultrasonic signal is also included in the generator. A motherboard is coupled to both the input module and the output module. The motherboard includes a digital controller adapted to control the input module and the output module.

Abstract: An ultrasonic welding probe power supply for powering more than one ultrasonic welding probe with power is provided. The power supply is adapted to provide power only to one welding probe at a time. A ringdown period is monitored between termination of provision of power to a first probe and the initiation of provision of power to a second probe during which provision of power to the second probe is disabled. Circuitry is provided within an ultrasonic welding probe controller to monitor probe activity and to control the interval between termination of provision of power to one probe and the initiation of provision of power to a second probe so that efficient and safe switching is made among ultrasonic probes.

Abstract: A mount for a vibration structure includes a ring having a flexural portion defining an arcuate mounting surface terminating at a free distal end and secured to an arcuate bearing surface on a flange of the vibration structure in coaxial bearing engagement therewith, the flexural portion having a radial stop surface spaced from the distal end and contacting an end surface of the vibration structure flange. Attachment structure on the mounting ring is adapted for attachment to an associated support. The flexural portion is resonant at the resonant frequency of the vibration structure and is shaped and dimensioned for flexing sufficient to accommodate movement of the bearing surface at resonance.

Abstract: An ultrasonic generator has an output circuit for delivering ultrasonic power to a load through a transducer, the generator having an amplitude control input coupled to the output of a comparator, the inputs of which are coupled to a user interface circuit. The output circuit produces voltage and current signals which are applied to a multiplier in the interface circuit, which produces a power signal applied to an error input of the comparator, the interface circuit also having a signal processor which receives a user-input reference and applies it to a reference input of the comparator. The output of the comparator regulates the power output of the generator to the reference level, and is also coupled to an indicator circuit for providing an visual indication of whether or not the apparatus is in regulation.

Abstract: A pre-stressed, sandwich-type, ultrasonic transducer assembly includes front and rear mass members having stacked therebetween alternating piezoelectric members and electrode members, with each of the members having surfaces which are substantially flat except for minute surface irregularities. Thin, soft, aluminum foil washers are respectively disposed between the facing surfaces of adjacent members of the stack. At least one bolt joins the front and rear mass members to subject it to a compressive pre-load, under which load the washers deform to follow the surface irregularities of the adjacent member surfaces and thereby fill inter-element voids created by such irregularities.

Abstract: A compliant workpiece support assembly for a microrobotic apparatus for aligning three workpieces and welding them into an assembled package, includes a lower support assembly having a ball and socket joint with a polymer ball seat cast around the ball. The ball has a radial bore containing a lower collet axially movable in the bore to grip one of the workpieces. The other two workpieces are held in telescoping arrangement, respectively in inner and outer collets of an upper support assembly, the collets being disposed coaxially one within the other and respectively having camming housings for opening and closing the collets. The outer collet housing supports the entire upper support assembly and is axially driven so that when the outer collet bottoms on the outer workpiece the continued movement of the outer housing closes the collet to grip the workpiece. The inner collet is closed over the inner workpiece by a pneumatic piston.

Abstract: A portable foldable overhead projector includes a housing having a front opening communicating with an interior cavity, and a bottom aperture communicating with the cavity and closable by a pair of pivoting doors which, when open, support the housing on support legs and accommodate movement of a mirror inside the housing between stowed and use positions. In the use position the mirror reflects light from a source through a transmitting stage in the top wall of the housing which forms a pivoting door to provide further access to the cavity. A mast pivots along the outside of the housing and carries a foldable projection head assembly on a rack and pinion mechanism. When the mast is lowered the rack and pinion can be operated to move the folded projection head assembly through the front opening into the cavity for storage.