Method for controlling an ultrasonic machining process

• US 8,702,883 B2
• Filed: 07/12/2013
• Issued: 04/22/2014
• Est. Priority Date: 07/18/2012
• Status: Expired

• Current Assignee: Herrmann Ultraschalltechnik GmbH & Co. KG
• Original Assignee: Herrmann Ultraschalltechnik GmbH & Co. KG
• Inventors: Herrmann, Thomas, Aust, Volker
• Primary Examiner(s): SELLS, JAMES D
• Application Number:
  US13/940,743
• Publication Number:
  US 20140020816A1
• Time in Patent Office: 284 Days
• Field of Search: 156/64, 156/73.1, 156/358, 156/359, 156/366, 156/580, 156/580.2
• US Class Current: 156/64
• CPC Class Codes: B23K 20/10 making use of vibrations, e.g. ultrasonic welding
• CPC Class Codes: B29C 65/08 using ultrasonic vibrations non-plastics element to plastics elements B29C65/645
• CPC Class Codes: B29C 66/92445 by steps
• CPC Class Codes: B29C 66/93431 the speed being kept constant over time
• CPC Class Codes: B29C 66/942 by measuring the time
• CPC Class Codes: B29C 66/9512 by controlling their vibration frequency
• CPC Class Codes: B29C 66/9516 by controlling their vibration amplitude
• CPC Class Codes: B29C 66/961 involving a feedback loop mechanism, e.g. comparison with a desired value

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 value 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 value 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, 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 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 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.

8. Method according to any one of claims 1 to 3, characterised in that 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 value differ.

9. Method according to claim 8, characterised in that 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.