US 11,449,027 B2Granted

Method and a system for reducing vibrations in a mechanical processing for removal of chippings

AssigneeMandelli S.p.A.

InventorPaolo Albertelli

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Abstract

A method for reducing vibrations originating in a mechanical processing for removal of swarf comprising monitoring the vibration resulting from contact between the tool and workpiece, detecting the occurrence of a regenerative vibratory phenomenon, calculating the frequency of the phenomenon, estimating a value representing a resonance frequency of the machine as a function of the frequency of the phenomenon and determining a threshold value on the basis of the value. Also, comparing the operating speed of the mandrel with the threshold value and reducing the intensity of the phenomenon by a first reduction strategy based on correction of the operating speed of the mandrel being greater than the threshold value or by a second reduction strategy based on a continuous modulation which imparts an oscillation to the speed around the value of the operating speed, when the operating speed of the mandrel is less than the threshold value.

Claims18

Dependent claims

A method for reducing vibrations originating from a mechanical processing for removing swarf, the mechanical processing being carried out by a machine tool having a mandrel rotating at a relative operating speed on which is mounted a cutting tool having one or more cutting edges defining a plurality of characteristic frequencies of the machine tool, the method comprising the following steps:

monitoring a vibration which arises from a contact between the cutting tool and a workpiece;
measuring an occurrence of a regenerative vibratory phenomenon when the vibration exceeds a pre-set limit value or has a frequency content which is not related to the characteristic frequencies;
calculating a frequency of the vibratory phenomenon;
estimating a value representing a resonance frequency of the machine tool as a function of the frequency of the vibratory phenomenon;
determining a threshold value based on the value representing the resonance frequency;
comparing between a real-time value of the operating speed of the mandrel and the threshold value;
reducing an intensity of the vibratory phenomenon by an execution of:
a first reduction strategy based on a modification of the operating speed when the real-time value of the operating speed of the mandrel is greater than the threshold value;
a second reduction strategy based on a continuous modulation which imparts an oscillation to the operating speed about the real-time value, when the real-time value of the operating speed of the mandrel is less than the threshold value.

6 more elements

A system for reducing vibrations for a machine tool, comprising:

a sensor configured for monitoring a vibration which arises from a contact between a cutting tool and a workpiece being processed and providing a signal representing the vibration;
an interface configured to be placed in communication with a control unit of the machine tool;
a processing unit operatively connected with the sensor and the interface to exchange signals with the sensor and the interface and configured for:
comparing the signal representing the vibration with one or more pre-set reference parameters;
activating a method of reducing the vibration if the signal representing the vibration exceeds one or more pre-set reference parameters;
wherein at least one chosen from the interface and the processing unit is configured for:
calculating a frequency of the vibration;
estimating a value representing a resonance frequency of the machine tool as a function of the frequency of the vibration;
determining a threshold value based on the value representing the resonance frequency;
comparing a real-time value of an operating speed of a mandrel of the machine tool with the threshold value;
adopting a first reduction strategy based on a modification of the operating speed when the real-time value of the operating speed of the mandrel is greater than the threshold value,
adopting a second reduction strategy based on a continuous modulation which imparts an oscillation to the operating speed about the real-time value, when the real-time value of the operating speed of the mandrel is less than the threshold value.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/771,598Filed 7 Dec 2018
Priority: IT 10201700014300112 Dec 2017
Published: US 2020/0301390 A124 Sep 2020
Granted: 20 Sep 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G05B 19/19
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
G05B 19/182
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
G05B 19/414
Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to…
G05B 2219/37346
Measurements: cutting, chip quality