Abstract:
A method for testing the integrity of a stack during ultrasonic welding, includes the steps of: (i) ultrasonically welding two or more work pieces with a stack, the stack including a convertor and a horn; (ii) measuring a frequency profile based on a vibration of the horn during the welding step; and (iii) comparing the measured frequency profile to a standard frequency profile to obtain an error rate, the error rate being indicative of a difference between the measured frequency profile and the standard frequency profile. A system employing the aforementioned method is also provided.
Abstract:
An electrical waveform generator for driving an electromechanical load includes a digital signal processor connected to a waveform generator component in turn connected to an amplifier section with a filter network, the latter being connected to sensing and conditioning circuit componentry that is in turn connected to analog-to-digital converter circuitry. A digital memory stores digitized voltage and current waveform information. The processor determines a phase difference between voltage and current waveforms, compares the determined phase difference to a phase difference command and generates a phase error or correction signal. The processor also generates an amplitude error signal for inducing the amplifier section to change its output amplitude to result in a predetermined amplitude error level for a respective one of the voltage and current waveforms.
Abstract:
The present invention relates to an output stage for adapting an AC voltage signal of an ultrasound generator to a converter connectable to the output stage, wherein the output stage has two input terminals for receiving the AC voltage produced by the ultrasound generator and two output terminals for outputting an adapted AC voltage, as well as an output transformer with a primary coil having a number n1 turns and a secondary coil with a number n2 turns, the output transformer having a main inductance LH as well as a leakage inductance Lσ, the two input terminals being connected to one another via the primary coil and the two output terminals being connected to one another via the secondary coil. In order to disclose an output transformer, which allows an economical and uncomplicated adaptation of a generator output to the converter input, it is proposed according to the invention that a filter capacitor CP is provided, which either connects the two output terminals in parallel to the secondary coil or connects an output terminal to a tap of the secondary coil or is connected to a filter coil with n3 turns, which is inductively coupled to the primary and the secondary coil.
Abstract:
The invention relates to a torsion sonotrode, comprising two mutually opposing end faces (S1, S2) and a circumferential surface (U) which surrounds a torsion axis (T) and on which at least one working surface (A1, A2, A3, A4) is provided at a radial distance from the torsion axis (T).
Abstract:
The invention relates to a torsion sonotrode, comprising two mutually opposing end faces (S1, S2) and a circumferential surface (U) which surrounds a torsion axis (T) and on which at least one working surface (A1, A2, A3, A4) is provided at a radial distance from the torsion axis (T).
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.
Abstract:
The invention utilizes a multiple frequency ultrasound generator driving a multiple frequency harmonic transducer array to improve cleaning and processing effects while eliminating damage to parts being cleaned. An AC switch and circuitry to modify the output of an ultrasound generator in combination with techniques such as random AM and FM signals are used to produce ultrasound waves that have no single frequency components which eliminates exciting parts being cleaned into resonance. Generator signals that increase cavitation efficiency and that have successive time periods with predominately stable cavitation and predominantly transient cavitation further improve the performance of the cleaning or processing systems.
Abstract:
The invention utilizes a multiple frequency ultrasound generator driving a multiple frequency harmonic transducer array to improve cleaning and processing effects while eliminating damage to parts being cleaned. An AC switch and circuitry to modify the output of an ultrasound generator in combination with techniques such as random AM and FM signals are used to produce ultrasound waves that have no single frequency components which eliminates exciting parts being cleaned into resonance.
Abstract:
A method and apparatus for determining the resonance frequency for a vibration welder are described. The vibration frequencies at a predetermined vibration level and on both sides of the resonance frequency are derived and are then used to determine and operate the vibration welder at the resonance frequency. In one embodiment the vibration frequency of the vibration welder is swept up from one side of the resonance point and the vibration amplitude is monitored and a first frequency at a particular vibration amplitude is determined. The same sweeping is done from the other side of the resonance point and a second frequency determined for the same vibration amplitude reference level but on the other side of the resonance frequency. The two measured frequencies are then combined to yield the resonance frequency which can then be used to operate the vibration welder.
Abstract:
An ultrasonic processing method is disclosed wherein during the processing time interval the motional amplitude and engaging force of the resonating horn and thereby the power and engaging pressure to the workpiece is varied to improve weld strength and decrease weld cycle time. The variation in motional amplitude and engaging force may be in response to a process condition such as a change in dimensions of the workpiece, a sharp rise in the transducer power curve, or in response to the lapse of a predetermined time interval.