Method for controlling an ultrasonic machining process

Abstract

Invention relating to a method for controlling an ultrasonic machining, in which an ultrasonic vibration is transmitted via a sonotrode into the material to be machined. During the first machining interval, a first welding variable of the group S, consisting of the frequency f and the amplitude ü of the ultrasonic vibration, the force F, which the sonotrode exerts on the material to be machined, the power P, which the generator delivers, and the speed v, with which the sonotrode is moved in the direction of the material to be machined, is kept constant until a first target variable of the group Z adopts a predetermined value. During an adjoining second machining interval, a second welding variable of the group S is kept constant until a second target variable of the group Z adopts a predetermined value, wherein the first and the second target variable differ.

Claims

.[.1. Method for controlling an ultrasonic machining process, in which an ultrasonic vibration of the frequency f is transmitted with the aid of a sonotrode made to carry out an ultrasonic vibration under a pressure into the material to be machined, wherein, during a first machining interval, a first welding variable of the group S, consisting of the frequency f of the ultrasonic vibration, the amplitude ü of the ultrasonic vibration of the sonotrode, the force F, which the sonotrode exerts on the material to be machined, the power P, which the generator delivers, and the speed v, with which the sonotrode is moved in the direction of the material to be machined, f is kept constant) until a first target variable of the group Z, consisting of the force F, the power P, the welding time t since the beginning of this machining interval, during which the excited sonotrode transmits the ultrasonic vibration under pressure into the material to be machined, the welding path s, which the sonotrode has covered since the beginning of the machining interval, and the energy E, calculated from the product of P and t, adopts a predetermined value, and, during a second machining interval, which adjoins the first machining interval, a second welding variable of the group S is kept constant until a second target variable of the group Z adopts a predetermined value, wherein the first and the second target variable differ..].

.[.2. Method according to claim 1, characterised in that the first and the second welding variable are the same..].

.[.3. Method according to claim 2, characterised in that the first and the second welding variable are the force F, which the sonotrode exerts on the product to be machined..].

4. .[.Method according to any one of claims 1 to 3, characterised in that,.]. .Iadd.Method for controlling an ultrasonic machining process, in which an ultrasonic vibration of the frequency f is transmitted with the aid of a sonotrode made to carry out an ultrasonic vibration under a pressure into the material to be machined, wherein, during a first machining interval, a first welding variable of the group S, consisting of the frequency f of the ultrasonic vibration, the amplitude ü of the ultrasonic vibration of the sonotrode, the force F, which the sonotrode exerts on the material to be machined, the power P, which the generator delivers, and the speed v, with which the sonotrode is moved in the direction of the material to be machined, is kept constant until a first target variable of the group Z, consisting of the force F, the power P, the welding time t since the beginning of this machining interval, during which the excited sonotrode transmits the ultrasonic vibration under pressure into the material to be machined, the welding path s, which the sonotrode has covered since the beginning of the machining interval, and the energy E, calculated from the product of P and t, adopts a predetermined value, and, during a second machining interval, which adjoins the first machining interval, a second welding variable of the group S is kept constant until a second target variable of the group Z adopts a predetermined value, wherein the first and the second target variable differ, and wherein .Iaddend.during the first machining interval, a third target variable of the group Z is detected and the second target variable is selected depending on the result of the detection.

5. Method according to claim 4, .[.characterised in that.]. .Iadd.wherein .Iaddend.the third target variable is the welding time t.

.[.6. Method according to any one of claims 1 to 3, characterised in that the first machining interval ends when the first target variable adopts the predetermined value or when a fourth target variable of the group Z adopts a predetermined value..].

7. .[.Method according to any one of claims 1 to 3, characterised in that.]. .Iadd.Method for controlling an ultrasonic machining process, in which an ultrasonic vibration of the frequency f is transmitted with the aid of a sonotrode made to carry out an ultrasonic vibration under a pressure into the material to be machined, wherein, during a first machining interval, a first welding variable of the group S, consisting of the frequency f of the ultrasonic vibration, the amplitude ü of the ultrasonic vibration of the sonotrode, the force F, which the sonotrode exerts on the material to be machined, the power P, which the generator delivers, and the speed v, with which the sonotrode is moved in the direction of the material to be machined, is kept constant until a first target variable of the group Z, consisting of the force F, the power P, the welding path s, which the sonotrode has covered since the beginning of the machining interval, and the energy E, calculated from the product of P and the welding time t since the beginning of this machining interval, during which the excited sonotrode transmits the ultrasonic vibration under pressure into the material to be machined, adopts a predetermined value, and, during a second machining interval, which adjoins the first machining interval, a second welding variable of the group S is kept constant until a second target variable of the group Z adopts a predetermined value, wherein the first and the second target variable differ, and wherein .Iaddend.an upper and/or lower limit .[.optionally depending on the welding time t.]. is predetermined for the first and/or the second target variable and, when the upper limit is exceeded or the lower limit is fallen below, the machining interval is ended and a transition is made into the next machining interval or the welding process is discontinued .Iadd.wherein the upper and/or the lower limit is dependent on the welding time.Iaddend..

8. .[.Method according to any one of claims 1 to 3, characterised in that.]. .Iadd.Method for controlling an ultrasonic machining process, in which an ultrasonic vibration of the frequency f is transmitted with the aid of a sonotrode made to carry out an ultrasonic vibration under a pressure into the material to be machined, wherein, during a first machining interval, a first welding variable of the group S, consisting of the frequency f of the ultrasonic vibration, the amplitude ü of the ultrasonic vibration of the sonotrode, the force F, which the sonotrode exerts on the material to be machined, the power P, which the generator delivers, and the speed v, with which the sonotrode is moved in the direction of the material to be machined, is kept constant until a first target variable of the group Z, consisting of the force F, the power P, the welding time t since the beginning of this machining interval, during which the excited sonotrode transmits the ultrasonic vibration under pressure into the material to be machined, the welding path s, which the sonotrode has covered since the beginning of the machining interval, and the energy E, calculated from the product of P and t, adopts a predetermined value, and, during a second machining interval, which adjoins the first machining interval, a second welding variable of the group S is kept constant until a second target variable of the group Z adopts a predetermined value, wherein the first and the second target variable differ, and wherein .Iaddend.during a third machining interval, which adjoins the second machining interval, a third welding variable of the group S is kept constant until a fifth target variable of the group Z adopts a predetermined value, wherein the second and the fifth target variable differ.

9. Method according to claim 8, .[.characterised in that.]. .Iadd.wherein .Iaddend.more than three machining intervals are provided, during which, in each case, a welding variable of the group S is kept constant until, in each case, a target variable of the group Z adopts a predetermined value.

.Iadd.10. Method according to claim 4, wherein the first and the second welding variable are the same. .Iaddend.

.Iadd.11. Method according to claim 10, wherein the first and the second welding variable are the force F, which the sonotrode exerts on the product to be machined. .Iaddend.

.Iadd.12. Method according to claim 7, wherein the first and the second welding variable are the same. .Iaddend.

.Iadd.13. Method according to claim 12, wherein the first and the second welding variable are the force F, which the sonotrode exerts on the product to be machined. .Iaddend.

.Iadd.14. Method according to claim 8, wherein the first and the second welding variable are the same. .Iaddend.

.Iadd.15. Method according to claim 14, wherein the first and the second welding variable are the force F, which the sonotrode exerts on the product to be machined. .Iaddend.

.Iadd.16. Method for controlling an ultrasonic machining process, in which an ultrasonic vibration of the frequency f is transmitted with the aid of a sonotrode made to carry out an ultrasonic vibration under a pressure into the material to be machined, wherein, during a first machining interval, a first welding variable of the group S, consisting of the frequency f of the ultrasonic vibration, the amplitude ü of the ultrasonic vibration of the sonotrode, the force F, which the sonotrode exerts on the material to be machined, the power P, which the generator delivers, and the speed v, with which the sonotrode is moved in the direction of the material to be machined, is kept constant until a first target variable of the group Z, consisting of the force F, the power P, the welding time t since the beginning of this machining interval, during which the excited sonotrode transmits the ultrasonic vibration under pressure into the material to be machined, the welding path s, which the sonotrode has covered since the beginning of the machining interval, and the energy E, calculated from the product of P and t, adopts a predetermined value, and, during a second machining interval, which adjoins the first machining interval, a second welding variable of the group S is kept constant until a second target variable of the group Z adopts a predetermined value, wherein the first and the second target variable differ, wherein said first target variable and a fourth target variable of the group Z are detected during the first machining interval, and wherein the first machining interval ends when the first target variable adopts the predetermined value or wherein the first machining interval ends also when the fourth target variable of the group Z adopts a predetermined value, whichever occurs first. .Iaddend.

.Iadd.17. Method according to claim 16, wherein the first and the second welding variable are the same. .Iaddend.

.Iadd.18. Method according to claim 17, wherein the first and the second welding variable are the force F, which the sonotrode exerts on the product to be machined. .Iaddend.

Description

(1) Further advantages, features and application possibilities become clear with the aid of the following description of a preferred embodiment and the associated FIGURE. In the drawing:

(2) FIG. 1 shows a flow chart of a preferred embodiment.

(3) FIG. 1 shows a flow chart of a preferred embodiment of the method according to the invention. The first machining interval starts in step 1. The machining time t0 is measured in step 2. This measurement is merely used to determine the starting time.

(4) The sonotrode is then pressed with the predetermined force F.sub.1 onto the workpiece to be machined in step 3. The force F is selected as the welding variable. It is obvious that instead of the force F, a different welding variable of the group S could have also been selected.

(5) In step 4, the machining time t is measured. The machining time t is the target variable which has been selected for the first machining interval. A check is now made in step 5 whether since the beginning of the machining time measurement in step 2 a predetermined time interval t1 has already been exceeded or not. If the predetermined time period t1 has not yet been exceeded, the method continues with step 3, i.e. the sonotrode continues to be pressed with the predetermined force F.sub.1 onto the workpiece to be machined and, in step 4, the machining time t is measured again until the predetermined time period t1 has been reached. In this case, the first machining interval ends in step 6. In step 7, the second machining interval starts. The welding path s0 is measured here in step 8, i.e. the position of the sonotrode relative to the workpiece or a counter-tool, on which the workpiece is positioned.

(6) In step 9, the sonotrode is now pressed with a predetermined force F.sub.2 onto the workpiece to be machined. Ultrasonic machining takes place.

(7) In step 10, the welding paths is measured again. A check is now made in step 11 whether, since the beginning of the measurement in step 8, the sonotrode has moved relative to the workpiece by a distance which is greater than the predetermined welding path s1. If the predetermined welding path s1 has not yet been reached, the process is continued with step 9. If the desired welding path s1 has been reached, the second machining interval ends in step 12.

(8) Since the machining method according to the invention provides the division of the machining into at least two machining intervals, the target variables being selected differently, a very good welding result can be achieved.