Abstract:
A closed-loop ultrasonic welding apparatus for sealing or welding thermoplastic material on a continuous basis wherein the material to be welded (10,12) is fed through a weld station (14) comprising a horn (18) and anvil (16). The apparatus includes means for providing a first signal (30) commensurate with a desired ultrasonic energy density in the material when welded, a second signal (42) responsive to the feed speed of the material through the weld station (14), and a third signal commensurate with the power coupled by a power supply (22) via a transducer (26) and the horn (18) to the material (10,12) at the weld station (14). Control means (32) receive the first, second and third signals and produce an error signal, which is responsive to the difference between the desired energy density and the actual energy density coupled to the material. After being subjected to further processing the error signal is converted to a control signal for controlling the output from said power supply and/or controlling the engagement force between the horn and material. Hence, the welding apparatus causes a predetermined energy density in the welded material irrespective of disturbances or changes in feed speed, engagement force between the horn and material, or the material itself.
Abstract:
An ultrasonic processing method and apparatus are disclosed wherein during the processing time interval the motional amplitude of the resonating horn and thereby the power to the workpiece is changed responsive to the production of a control signal. The control signal is process related and generated, in a typical example, when there is sharp rise in the power curve. In another example, the power is changed responsive to a changing dimension of the workpiece. In typical examples, the control signal reduces the motional amplitude for the remaining time interval.
Abstract:
PURPOSE: Simultaneous amplitude and force profiling is provided to improve decrease weld cycle time and increase weld strength with accompanying improvements in cosmetic appearances and weld reliability. CONSTITUTION: A motional amplitude and horn engaging force are varied in accordance with predetermined profiles or in response to process related control signals over the weld cycle. And the motional amplitude and horn engaging force are increased for the initial portion of the weld cycle to accelerate the preheating and melting of workpieces in the region of the weld line to be formed, and then, after this initial portion of the weld cycle, gradually decreased to complete the weld formation. Full control of bond line temperature and squeeze flow of the melt within the weld is provided by simultaneous variation of the motional amplitude and engaging force of the horn.
Abstract:
The present invention concerns an ultrasonic welding installation comprising an ultrasonic vibration unit having a sonotrode and a converter, wherein the sonotrode and the converter are arranged in mutually adjacent relationship along a longitudinal axis and the ultrasonic vibration unit can be caused to resonate with an ultrasonic vibration in the direction of the longitudinal axis with a wavelength λ/2, wherein there is provided a holder for holding the ultrasonic vibration unit. To provide an ultrasonic welding installation which allows simple and quick highly precise adjustment of the sealing surfaces of the sonotrode relative to the anvil it is proposed according to the invention that the holder has an angle positioning device, wherein the angle positioning device and the ultrasonic vibration unit are of such a configuration that they can be connected together in positively locking relationship so that a rotation of the ultrasonic vibration unit about the longitudinal axis is prevented by the positively locking connection and a relative movement between the ultrasonic vibration unit and the holder in the direction of the longitudinal axis is not prevented.
Abstract:
A control device for reducing and homogenizing welding residual stress by acoustic waves, comprising: a fixing tool having two rows of through holes; a plurality of ultrasonic transducers each having a body and a conical horn transmitting portion at a lower end of the body, wherein lower ends of the horn transmitting portions are fixedly connected with flanges, the horn transmitting portions of the ultrasonic transducers extend into respective through holes of the fixing tool to be in contact with welded parts below the fixing tool, the flanges are fixed to the fixing tool by bolts, and the two rows of through holes are arranged both sides of a welding seam of the welded parts; and a driving device for driving the ultrasonic transducers to operate. A corresponding control method is also provided. The control device can be used to control residual stress at the welding seam of steels.
Abstract:
The invention relates to a sonotrode (100; 100′; 100″), comprising a sonotrode body (10; 10′; 10″), which has at least one contact region (12; 12′; 12″) for applying high-frequency mechanical vibrations, introduced at at least one introduction region (14; 14′; 14″) of the sonotrode body (10; 10′; 10″) by a vibration unit, to at least one workpiece (200; 200′; 200″) or material or to a further tool acting thereon, and a heat dissipation device, by means of which heat can be dissipated from the contact region.
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 to effect reciprocating movement of the first workpiece support.