Wire-sawing machine

Details Wire-sawing machine Wire-sawing machine

2000-01-21

2001-05-29

Hail, III, Joseph J. (Department: 3723)

Stone working

Sawing

Reciprocating

C125S021000, C451S005000

Reexamination Certificate

active

06237585

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a wire-sawing machine which can previously inhibit rupture of a wire used for slicing an ingot.
2. Brief Description of the Prior Art
After top and tail parts are cut off an ingot produced by a pulling method or the like, the ingot is ground at its periphery, subjected to orientation flat processing and then sliced to wafers of predetermined thickness. Although an inner blade slicer has been used so far for such ingot-slicing, it can not well cope with enlarged of wafers. Therefore, a wire saw using a piano wire has been widely adopted in response to an intensified demand for wafers enlarged in size.
A conventional wire-sawing machine has three grooved rollers
1
-
3
, one of which (the roller
3
) is coupled to a drive motor
4
, as shown in
FIG. 1. A
wire
5
is pulled out from a reel
6
, passed around the grooved rollers
1
to
3
multiple times and then wound on another reel
7
. A tensioner
8
applies a tension to the wire
5
. Thus, the wire travels in a stretched state along a travel path around the grooved rollers
1
to
3
.
An ingot
9
to be sliced is fixed to a holder
10
using a proper adhesion jig and located at a position between the grooved rollers
1
and
2
. The ingot
9
is sliced to a plurality of wafers by cutting motion of the wire
5
. During slicing, slurry
11
is supplied from a slurry tank
12
through a supply tube
13
to a nozzle
14
, sprayed onto the wire
5
, collected in a pan
15
and then returned to the slurry tank
12
, in order to promote the cutting motion. The slurry
11
is cooled by circulation between the slurry tank
12
and a heat exchanger
16
.
The wire
5
is sent out form the reel
6
through deflector rollers
18
to the grooved rollers
1
to
3
, used for slicing the ingot
9
during one way passing along a direction d
1
, forwarded through other deflector rollers
18
to another reel
7
, and then wound on the reel
7
, as shown in FIG.
2
. The wire
5
may be bi-directionally forwarded, instead. That is, a travel of the wire
5
along a direction d
2
together with the travel along the direction d
1
is periodically repeated in the manner such that the wire
5
is successively wound on the reel
7
as a whole.
A tension is applied to the wire
5
in order to slice the ingot
9
under stable conditions. Such a tension is applied by the pendulum-type tensioner
8
(shown in FIG.
1
), a balance weight
17
(shown in
FIG. 2
) or a powder clutch (not shown). For instance, the wire
5
is sent along a travel path around a dancer roller
19
provided between the inlet-side deflector roller
18
and the outlet-side deflector roller
18
. The dancer roller
19
supports a balance weight
17
for application of a predetermined tension.
The tension applied to the wire occasionally increases during travelling of the wire
5
. Especially, increase of tension likely occurs when a travelling direction of the wire
5
is switched as d
1
→d
2
or d
2
→d
1
. An increasing part of the tension is somewhat absorbed by upward turning of the tensioner (FIG.
1
), upward motion of the dancer roller
19
(
FIG. 2
) or rotation of a powder clutch (not shown). However, abrupt increase of the tension is not compensated for with such motion of the tensioner
8
, the dancer roller
19
or the powder clutches.
Such abrupt increase of the tension, i.e. abnormal tension, causes rupture of the wire
5
regardless of such tension-controlling means as the tensioner
8
, the dancer roller
19
or the powder clutch. When the wire
5
is broken, wire-sawing operation is inevitably interrupted. In addition, a lot of works and time are required for detaching the broken wire
5
and stretching a new wire
5
, resulting in reduction of productivity.
SUMMARY OF THE INVENTION
The present invention aims at operation of a wire-sawing machine under stable conditions by judging a sign predicting abnormal increase of a tension applied to a wire and performing proper action such as operation-stop or tension relaxation in order to previously prevent rupture of the wire.
The newly proposed wire-sawing machine includes:
a plurality of grooved rollers having a plurality of grooves for travel paths of an ingot-slicing wire on peripheries thereof,
a wire reel for sending a new wire through deflector rollers to the grooved rollers,
another wire reel for winding a wire sent out from the grooved rollers through other deflector rollers,
a tensioner for applying a predetermined tension to the travelling wire,
a tension sensor for detecting a tension applied to the wire, provided at a position between the grooved rollers and the deflector rollers,
calculating and judging circuits to which a detected value of the tension applied to the wire is inputted for judging a sign predicting abnormal increase of the tension from a fluctuating gap of the tension, a fluctuation velocity of the tension and/or an acceleration of the tension, and
a controller to which a signal predicting abnormal increase of the tension is inputted from the calculating and judging circuits for outputting an operation-stop signal or an alarm in response to the predicting signal.
A sign predicting abnormal increase of said tension may be represented by vertical motion of a dancer roller which applies a tension to the wire. In this case, abnormal increase of the tension is predicted from a fluctuation gap of the vertical motion, a fluctuation velocity of the vertical motion and/or acceleration of the vertical motion. The fluctuation of the tension of the wire may be combinatively used with vertical displacement of the dancer rollers for getting a predicting sign with a high reliability.


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patent: 3831576 (1974-08-01), Mech
patent: 5564409 (1996-10-01), Bonzo et al.
patent: 5715807 (1998-02-01), Toyama et al.
patent: 5829424 (1998-11-01), Hauser
patent: 5907988 (1999-01-01), Kiuchi et al.
patent: 63-062655 (1988-03-01), None
patent: 63-260757 (1988-10-01), None
patent: 01177958 (1989-07-01), None
patent: 09094755 (1997-04-01), None
patent: 10119031 (1998-05-01), None
patent: 10193340 (1998-07-01), None

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