Device for processing workpieces

Abstract

A device for processing workpieces uses ultrasound, with an resonant system comprising an ultrasound generator, an ultrasound sonotrode, and an anvil, wherein a workpiece is processed between the anvil and the ultrasound sonotrode. The ultrasound generator comprises a regulation means which has a regulation member connected upstream of the ultrasound generator to receive a feedback signal from the resonant system and to generate a regulation variable which is supplied to the ultrasound generator. A connecting point is provided between the regulation member and the ultrasound generator, at which the regulation variable of the regulation member is linked to a process variable from the processing procedure.

Description

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a diagram of the regulation process; and

FIG. 2 shows an oscillation curve of the amplitude in case of a disturbance.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a diagram of a regulation device, in which reference numeral 10 designates an resonant system which has an ultrasound generator 12, a booster 14, an ultrasound sonotrode 16 and an anvil 18, wherein the ultrasound sonotrode 16 and the anvil 18 represent the tool for processing a workpiece 20.

Parameters and signals (u) from this resonant system 10 are supplied to a regulation means 24 via a return path 22. This regulation means 24 has a PID controller 26. The regulation means 24 generates a regulation variable (s) which is supplied to the resonant system 10 and, in particular, to the ultrasound generator 12. The resonant system 10 with regulation means 24 forms a regulated, electrical and mechanical resonant circuit 28, as is disclosed in prior art.

Reference numeral 30 designates a processing procedure, in particular, a welding process outside of the resonant circuit 28, since it is not directly influenced by the electrical and mechanical variables. This processing procedure 30 is connected to a force sensor 32 which detects the course of the welding force. The force sensor 32 determines a process variable (p) which is supplied to a scaling unit 34. This scaling unit 34 provides a scaled process variable (p′) which is supplied to a connecting point 36. This connecting point 36 is located between the regulation means 24 and the resonant system 10, such that not only the scaled process variable (p′) is supplied to the connecting point 36, but also the regulation variable (s). The connected variables (p′) and (s) are supplied to the resonant system 10 and, in particular, to the ultrasound generator 12.

It is clearly shown that in the inventive system, a variable that is generated outside of the resonant circuit 28, i.e. the process variable (p), is supplied to the resonant system 10.

FIG. 2 shows the time dependence of the amplitude (A), wherein 38 indicates a disturbance signal. In conventional systems, the dependence of the amplitude signal 40 shows strong fluctuations with overswinging, wherein in the inventive system, the amplitude signal 42 is regulated much more quickly to the original value. One can also see that the regulation frequency is shorter than in a conventional system, in particular half.

Claims

1. A device for processing a workpiece using ultrasound, the device comprising: an ultrasound generator;an ultrasound sonotrode cooperating with said ultrasound generator;an anvil, wherein the workpiece is processed between said anvil and said ultrasound sonotrode, said generator, sonotrode and anvil forming a resonant system;means for generating a feedback signal from said resonant system;a regulation means having a regulation member and connected upstream of said ultrasound generator, said regulation means receiving said feedback signal and generating a regulation variable;means for extracting a process variable in response to processing of the workpiece; andconnecting means disposed between said regulation member and said ultrasound generator to link said regulation variable to said processing variable and to subsequently pass said regulation variable to said ultrasound generator.

2. The device of claim 1, wherein said process variable is a processing force of said ultrasound sonotrode.

3. The device of claim 1, wherein said process variable is a processing temperature of a tip of said ultrasound sonotrode.

4. The device of claim 1, wherein said process variable is a signal that detects or reflects deformation of said resonant system.

5. The device of claim 1, wherein said process variable is a predetermined signal that synchronously accompanies processing of the workpiece.

6. The device of claim 1, wherein in said regulation means has a PID controller.

7. The device of claim 1, further comprising a scaling element or a proportional controller for the process variable, disposed upstream of said connecting point means.

8. The device of claim 7, wherein said scaling element is an adaptive system.

9. The regulation means of the device for processing a workpieces of claim 1.