Title of Invention	A CUTTING TOOL INSERT WITH BUILT-IN PROVISION FOR DETECTING FLANK WEAR OF A PREDETERMINED VALUE
Abstract	A cutting tool insert with built-in provision for detecting flank wear of a predetermined value, comprising a rake face, a flank face and a cutting., edge, wherein the region of the flank face below the cutting edge is stepped to form an additional edge, whereby the cutting edge of the said ^insert normally projects outwardly, beyond the additional edge; and wherein the said region is structurally weakened, such that whenever flank , wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge comes 'Into contact with the work surface, to cause a fracture of the insert at the said region and thus result in sudden release of acoustic energy detectable by an acoustic sensor.

Title of Invention

A CUTTING TOOL INSERT WITH BUILT-IN PROVISION FOR DETECTING FLANK WEAR OF A PREDETERMINED VALUE

Abstract

A cutting tool insert with built-in provision for detecting flank wear of a predetermined value, comprising a rake face, a flank face and a cutting., edge, wherein the region of the flank face below the cutting edge is stepped to form an additional edge, whereby the cutting edge of the said ^insert normally projects outwardly, beyond the additional edge; and wherein the said region is structurally weakened, such that whenever flank , wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge comes 'Into contact with the work surface, to cause a fracture of the insert at the said region and thus result in sudden release of acoustic energy detectable by an acoustic sensor.

Full Text	This invention relates to a cutting tool insert with built-in provision for detecting flank wear of a predetermined value. In automated manufacturing, reliable monitoring of tool wear remains one of the important issues. Monitoring techniques known to the art are either direct or indirect. Direct monitoring techniques measure the tool wear parameters directly and are usually off-line. On the other hand, indirect techniques measure parameters like cutting forces or vibration, which are related to tool wear. These techniques are on-line, but often the relation between measured parameters and the wear is poor, leading to the necessity for multiple sensors and artificial neural network based solutions. The known art includes pneumatic sensing of flank wear in which the gap between a point on the flank face of the cutting tool and the rotating transient surface is measured using a pneumatic gauge. Touch trigger probes have also been employed to measure tool wear on site. ^Attempts have been made to detect tool flank wear reaching a limiting value by implanting a speck of radioactive element on the flank face at a specified distance below the cutting edge. As the flank wear reaches the limiting value the radio active element is removed by friction contact with the work piece. Thus the presence or absence of the radioactive element could indicate whether the tool had worn to the limit or not. Also known to the art is the ultrasonic transmitter-receiver pair employed to measure flank wear, by comparing signals reflected by the nose tip and the worn flank of the insert. This invention, however, proposes a cutting tool insert with a built-in provision for giving a positive, perceptible, indication of the flank wear having reached a predetermined value. The flank wear is also detectable by a known acoustic sensor. Other features of this invention will be apparent from the following further description thereof given hereunder. The cutting tool insert, according to this invention, comprises a rake face, a flank face and a cutting edge, wherein the region of the flanV face below the cutting edge is stepped to form an additional edge, whereby the cutting edge of the said insert normally projects outwardly, beyond the additional edge; and wherein the said region is structurally weakened, such that whenever flank wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge comes into contact with the work surface, to cause a fracture of the insert at the said region and thus result in sudden release ot acoustic energy detectable by an acoustic sensor. Reference will now be made to the accompanying drawings to illustrate, by way of example, and not by way of limitation, one of various possible embodiments of the cutting tool insert proposed herein. In the drawingsi Fig. 1 illustrates the embodiment with its rake face, flank face and additional edge Fig.2 illustrates the said embodiment with its cutting edge (unworn) in contact with the work surface Fig.3 illustrates the said embodiment with its cutting edge (worn out to the predetermined extent) and the additional edge just coming into contact with the work surface. and Fig. 4 illustrates another view of the said embodiment with its cutting edge (unworn) in contact with the work surface The cutting tool insert I illustrated will be seen to have the rake face R, the flank face F and a cutting edge C. The region E of the flank face F below the cutting edge C is stepped at S to form an additional edge A whereby the cutting edge C of the said insert normally projects outwardly, beyond the additional edge A. The stepped region E is structurally weakened, such that whenever flank wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge A comes into contact with the work surface W, to cause a fracture of the insert at the weakened region £ and thus result in sudden release of acoustic energy. This energy is detectable by a knovn acoustic emission sensor mounted close to the cutting edge c under the tool holder. The signals from the sensor are amplified and used to activate an alarm (audio or visual) for indicating to the operator that predetermined flank wear has taken place. Even after the alarm has been activated, the turning operation can still go on at the cutting edge C, if the operator so wishes. On the other hand, the said signals can, alternatively or additionally, be used to activate a switching circuit to stop the machine either immediately or after a predetermined interval of time. One of several ways of structurally weakening the region E is by providing a recess T just beneath the said region. We Claim: 1. A cutting tool insert with built-in provision for detecting flank wear of a predetermined value, comprising a rake face, a flank face and a cutting edge, wherein the region of the flank face below the cutting edge is stepped to form an additional edge, whereby the cutting edge of the said insert normally projects outwardly, beyond the additional edge; and wherein the said region is structurally weakened, such that whenever flank wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge comes into contact with the work surface, to cause a fracture of the insert at the said region and thus result in sudden release of acoustic energy detectable by an acoustic sensor. 2. A cutting tool insert as claimed in Claim 1 wherein a recess is provided just beneath the the region to structurally weaken it. 3. A cutting tool insert with built-in provision for detecting flank wear of a predetermined value substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

Full Text

This invention relates to a cutting tool insert with built-in provision for detecting flank wear of a predetermined value.
In automated manufacturing, reliable monitoring of tool wear remains one of the important issues.
Monitoring techniques known to the art are either direct or indirect. Direct monitoring techniques measure the tool wear parameters directly and are usually off-line. On the other hand, indirect techniques measure parameters like cutting forces or vibration, which are related to tool wear. These techniques are on-line, but often the relation between measured parameters and the wear is poor, leading to the necessity for multiple sensors and artificial neural network based solutions.
The known art includes pneumatic sensing of flank wear in which the gap between a point on the flank face of the cutting tool and the rotating transient surface is measured using a pneumatic gauge. Touch trigger probes have also been employed to measure tool wear on site.

^Attempts have been made to detect tool flank wear reaching a limiting value by implanting a speck of radioactive element on the flank face at a specified distance below the cutting edge. As the flank wear reaches the limiting value the radio active element is removed by friction contact with the work piece. Thus the presence or absence of the radioactive element could indicate whether the tool had worn to the limit or not.
Also known to the art is the ultrasonic transmitter-receiver pair employed to measure flank wear, by comparing signals reflected by the nose tip and the worn flank of the insert.
This invention, however, proposes a cutting tool insert with a built-in provision for giving a positive, perceptible, indication of the flank wear having reached a predetermined value. The flank wear is also detectable by a known acoustic sensor.
Other features of this invention will be apparent from the following further description thereof given hereunder.

The cutting tool insert, according to this invention, comprises a rake face, a flank face and a cutting edge, wherein the region of the flanV face below the cutting edge is stepped to form an additional edge, whereby the cutting edge of the said insert normally projects outwardly, beyond the additional edge; and wherein the said region is structurally weakened, such that whenever flank wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge comes into contact with the work surface, to cause a fracture of the insert at the said region and thus result in sudden release ot acoustic energy detectable by an acoustic sensor.
Reference will now be made to the accompanying
drawings to illustrate, by way of example, and not
by way of limitation, one of various possible
embodiments of the cutting tool insert proposed
herein. In the drawingsi
Fig. 1 illustrates the embodiment with its rake
face, flank face and additional edge
Fig.2 illustrates the said embodiment with its
cutting edge (unworn) in contact with the work

surface
Fig.3 illustrates the said embodiment with its cutting edge (worn out to the predetermined extent) and the additional edge just coming into contact with the work surface.
and
Fig. 4 illustrates another view of the said embodiment with its cutting edge (unworn) in contact with the work surface
The cutting tool insert I illustrated will be seen to have the rake face R, the flank face F and a cutting edge C.
The region E of the flank face F below the cutting edge C is stepped at S to form an additional edge A whereby the cutting edge C of the said insert normally projects outwardly, beyond the additional edge A.
The stepped region E is structurally weakened, such that whenever flank wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge A comes into contact with the work surface W, to cause a

fracture of the insert at the weakened region £ and thus result in sudden release of acoustic energy. This energy is detectable by a knovn acoustic emission sensor mounted close to the cutting edge c under the tool holder.
The signals from the sensor are amplified and used to activate an alarm (audio or visual) for indicating to the operator that predetermined flank wear has taken place. Even after the alarm has been activated, the turning operation can still go on at the cutting edge C, if the operator so wishes.
On the other hand, the said signals can, alternatively or additionally, be used to activate a switching circuit to stop the machine either immediately or after a predetermined interval of time.
One of several ways of structurally weakening the region E is by providing a recess T just beneath the said region.

We Claim:
1. A cutting tool insert with built-in provision for detecting flank wear of a predetermined value, comprising a rake face, a flank face and a cutting edge, wherein the region of the flank face below the cutting edge is stepped to form an additional edge, whereby the cutting edge of the said insert normally projects outwardly, beyond the additional edge; and wherein the said region is structurally weakened, such that whenever flank wear, during use of the said insert on a work surface, reaches a predetermined value, the additional edge comes into contact with the work surface, to cause a fracture of the insert at the said region and thus result in sudden release of acoustic energy detectable by an acoustic sensor.
2. A cutting tool insert as claimed in Claim 1 wherein a recess is provided just beneath the the
region to structurally weaken it.
3. A cutting tool insert with built-in provision
for detecting flank wear of a predetermined value
substantially as herein described with reference

to, and as illustrated in, the accompanying drawings.

Documents:

1219-mas-1999 abstract duplicate.pdf

1219-mas-1999 abstract.pdf

1219-mas-1999 claims duplicate.pdf

1219-mas-1999 claims.pdf

1219-mas-1999 correspondence-others.pdf

1219-mas-1999 correspondence-po.pdf

1219-mas-1999 description (complete) duplicate.pdf

1219-mas-1999 description (complete).pdf

1219-mas-1999 drawings duplicate.pdf

1219-mas-1999 drawings.pdf

1219-mas-1999 form-1.pdf

1219-mas-1999 form-19.pdf

1219-mas-1999 form-26.pdf

« Previous Patent

Next Patent »

Patent Number

201014

Indian Patent Application Number

1219/MAS/1999

PG Journal Number

30/2009

Publication Date

24-Jul-2009

Grant Date

Date of Filing

23-Dec-1999

Name of Patentee

INDIAN INSTITUTE OF TECHNOLOGY,

Applicant Address

IIT P.O., CHENNAI 600 036.

Inventors:

#	Inventor's Name	Inventor's Address
1	MARIAPPAN MURUGAN	INDIAN INSTITUTE OF TECHNOLOGY, IIT P.O., CHENNAI 600 036.
2	VASUDEVAN PILLAI RADHAKRISHNAN	INDIAN INSTITUTE OF TECHNOLOGY, IIT P.O., CHENNAI 600 036.

PCT International Classification Number

G05B19/405

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA