Ultrasonic processing system having a piezoelectric force sensor

Patent metadata

Field	Value
Publication number	US-10046518-B2
Application number	US-201515503923-A
Country	US
Kind code	B2
Filing date	Nov 3, 2015
Priority date	Nov 11, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

The present invention concerns an apparatus for ultrasonic processing of materials having an ultrasonic processing system comprising an ultrasound generator, a converter, a sonotrode and a counterpart tool and a feed unit with which the sonotrode and the counterpart tool can be moved towards each other or away from each other, wherein there is provided a force sensor with which the force that the ultrasonic processing system exerts on the materials to be processed can be measured. To provide a corresponding ultrasonic processing apparatus which allows a greater processing speed it is proposed according to the invention that the force sensor is a piezoelectric sensor whose output is converted into an electrical voltage by means of a charge amplifier and that there is provided a control device which either when the ultrasonic processing is not performing material processing short-circuits the piezoelectric sensor or adds a time-varying force compensation unit to the value measured by the piezoelectric sensor.

First claim

The invention claimed is:

1. Apparatus for ultrasonic processing of materials having an ultrasonic processing system comprising an ultrasound generator, a converter, a sonotrode and a counterpart tool and a feed unit with which the sonotrode and the counterpart tool can be moved towards each other or away from each other, wherein there is provided a force sensor with which the force that the ultrasonic processing system exerts on the materials to be processed can be measured, characterised in that the force sensor is a piezoelectric sensor whose output is converted into an electrical voltage by means of a charge amplifier and that there is provided a control device which either when the ultrasonic processing is not performing material processing short-circuits the piezoelectric sensor or adds a time varying force compensation unit to the value measured by the piezoelectric sensor.

2. Apparatus as set forth in claim 1 characterised in that the sonotrode and/or the counterpart tool have a substantially cylindrical carrier surface having at least one raised portion and is rotatable so that during processing the raised portion rotates about the axis of rotation and during a sealing time comes into contact with the material web, wherein there is provided a trigger device which determines the position of the raised portion, wherein the control device is so adapted that it short-circuits the piezoelectric sensor in dependence on position determination.

3. Apparatus as set forth in claim 2 characterised in that the control device is so adapted that it short-circuits the piezoelectric sensor when the raised portion is not in contact with the material to be processed.

4. Apparatus as set forth in claim 3 characterised in that the control device is so adapted that it short-circuits the piezoelectric sensor when a predetermined period of time has expired.

5. Apparatus as set forth in claim 3 characterised in that the control device is so adapted that it short-circuits the piezoelectric sensor when the trigger device has registered a predetermined number of contacts between the material and the raised portion.

6. Apparatus as set forth in claim 1 characterised in that the control device both short-circuits the piezoelectric sensor when the ultrasonic processing system is not performing any material processing and also adds a time-varying force compensation value to the value measured by the piezoelectric sensor.

7. Apparatus as set forth in claim 1 characterised in that the force compensation value is derived from a previously performed measurement of the drift of the piezoelectric sensor.

8. Apparatus as set forth in claim 6 characterised in that the force compensation value is derived from a previously performed measurement of the drift of the piezoelectric sensor.

Assignees

• Herrmann Ultraschalltechnik Gmbh & Co Kg

Inventors

• Vogler Ulrich

Classifications

• B29C66/92211 Primary

  with special measurement means or methods · CPC title

• B29C66/1122

  Single lap to lap joints, i.e. overlap joints (B29C66/45, B29C66/472, B29C66/52272 take precedence) · CPC title

• B06B3/00 Primary

  Methods or apparatus specially adapted for transmitting mechanical vibrations of infrasonic, sonic, or ultrasonic frequency · CPC title

• B29C65/086

  using a rotary anvil · CPC title

• G01L1/16

  using properties of piezoelectric devices · CPC title