Note: Descriptions are shown in the official language in which they were submitted.
2081593
M~T~D AND INS~ATTATION FOR MANUFACTURING R~CTANGULAR
EN~ .T~n MAGNET WIRB WITH IN-LINE ROLLING AND D~TTTNG
This invention relates to a method and an installation
for manufacturing rectangular enamelled magnet wire. More
particularly, it relates to an improved method and
installation wherein the rolling and enamelling operations
are combined into an in-line rolling and enamelling system.
The conventional method for manufacturing rectangular
enamelled magnet wire has remained unchanged for many years
and it is fraught with many problems mostly connected with
the input of the rectangular bare conductor into the
enamelling machine. Essentially the conventional method
involves four separate operations, namely: (a) shaving;
(b) drawing; (c) rolling; and (d) enamelling.
Thus, the conventional installation for manufacturing
enamelled magnet wire comprises four separate machines
which operate independently of one another. These are:
(a) a rod shaving machine into which continuous cast and
rolled rod is fed from 4500 kg coils and wherein the
surface of the rod is shaved off to present a bright, clear
surface suitable for subsequent enamelling, and whereafter
the shaved rod is wound onto stems for subsequent drawing;
(b) a breakdown machine where the shaved stems are drawn
to predetermined size of round bare wire which is then
wound onto 76 cm (30") reels for subsequent rolling;
(c) a rolling mill where the round bare wire is rolled at
high speed to form rectangular bare wire of desired size
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which is then wound onto 76 cm (30") reels and stored for
enamelling; and
(d) and enamelling machine into which the rectangular bare
wire is fed and which comprises an annealer, a cooling zone
and an enamel oven where the enamel coats are applied in a
continuou~ manner until a predetermined thickness of
insulation is achieved.
The quality of the rolled or rectangular conductor
which is entering the enamelling operation is of paramount
importance and it is this factor that offers most
opportunities for significant problems in the conventional
installation.
The major problems are:
(a) Scrap
In the current system, a scrap allowance is introduced
at the rolling stage and because of the variety of sizes
produced, this allowance becomes scrap irrespective of
whether the enamelling process uses it or not.
(b) Continuity of production
At present, due to the batch processing methods
required when utilizing a high speed rolling mill, large
quantities of the entering round wire for the rolling mill
and of shaped wire for the enamelling machine are required
to achieve continuity of production.
(c) Remakes
Shaped remakes, especially in small quantities, have
the effect of making the conventional rolling mills very
inefficient because of high set-up time required.
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(d) Brazes
Currently all spools of shaped (rectangular) bare wire
are brazed together to facilitate the continuous operation
of the enamelling machine. This is not a totally
satisfactory solution, since the braze is weaker than the
parent metal and also the wire on the bottom of the spool
and the action of the brazing process often scratches the
wire and leads to test failures.
(e) Surface Ouality
Due to its capital cost, a conventional ~olling mill
is not normally used exclusively for producing wire for
enamelling purposes and consequently a compromise has to be
made to achieve a surface finish on the wire to satisfy
several purposes. This, although the most practical
procedure under the circll~stances, is not an ideal
situation for the best possible enamelling operation.
(f) Wire Cleanliness
In the conventional process, a residue of rolling
lubricant is inevitably left on the wire surface. When the
wire is then stored on the reels for at least several
hours, this lubricant dries on the wire and is very
difficult to clean off. If the enamelling is delayed
further, the rolled wire is subjected to a combination of
dust, dirt and metal oxidation, which often lead to test
failures in the enamelling process.
(g) Wire Damage
In the conventional rolling operation, the rolled wire
is spooled onto a steel reel. Even with perfect winding,
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damage to the wire is inevitable at the points where the
wire contacts the sides of the reel and where the windings
cross over. Also, during subsequent moving of the reels or
wire by lift truck and/or by hand, damage to the wire
occasionally occurs due to mishandling.
(h) Tension
Conventionally, a controlled, consistent tension on
the enamelling machine is difficult to achieve, especially
on smaller sizes. The changing weight of the spool and the
changing effective braking torque combine to give
inconsistent results which can produce test failures.
(i) Size Variations
A conventional rolling mill holds the wire size, with
minimum variation, when it reaches operating speed and
hence equilibrium. During the starting and stopping
operations, more variation in the wire size is introduced
and this can lead to inconsistencies in the enamelling
operation.
(j) Productivity
Because of the continual problems associated with the
current process, as mentioned above, the opportunity to
obtain productivity improvements in the conventional system
per se are very limited.
It is an object of the present invention to provide a
method and an installation for manufacturing rectangular
enamelled magnet wire, which will obviate the above
disadvantages of the conventional system.
Another object of the invention is to provide an
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improved method and installation wherein the rolling and
enamelling operations are combined into one and are
operated in-line as a single system or operation.
Other objects and advantages of the invention will
become apparent from the following description.
Thus, the method of the present invention for the
manufacturing of rectangular enamelled magnet wire,
comprises feeding a rod made of suitable metal, such as
copper, into a shaving machine and shaving the surface
layer of the rod to produce a bright, clean surface
suitable for subsequent enamelling, then coiling the shaved
rod onto stems for drawing, then drawing the shaved stems
to predetermined size of round, bare magnet wire and
coiling the same onto stems and finally rolling the round
bare magnet wire to form a rectangular bare magnet wire of
predetermined size and enamelling said rectangular magnet
wire by annealing the same, cooling and then passing
through and enamel oven where the enamel coats are applied
until a predetermined thickness of insulation is achieved,
the novel method being characterized in that the rolling
and enamelling are carried out in-line as a single,
continuous operation.
The speed of the overall in-line operation is
controlled by the speed of enamelling and the rolling speed
is adjusted accordingly. The rolling-enamelling operation
also includes a self-contained lubrication of the wire as
it is being rolled.
The installation in accordance with the present
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invention comprises: a shaving machine for shaving the
surface of the rod fed into said machine to produce a
bright, clean surface; a rod breakdown machine for drawing
the shaved rod to a predetermined round, bare magnet wire;
and an in-line rolling and enamelling system for
transforming the round, bare magnet wire into a magnet wire
of predetermined rectangular shape and enamelling the same
in a single continuous operation. The rolling section and
the enamelling section of the system operate in tandem with
one another.
The enamelling section comprises an annealer, followed
by a cooling zone and followed by an enamel oven and an
enamel capstan pulling the wire through the system. Also,
a dancer arrangement is provided within the rolling section
for controlling the speed of the rolling section relative
to the speed of the enamelling section which is controlled
by the enamel capstan which also provides a constant and
controlled tension. The rolling section further comprises
a self-contained lubrication unit to lubricate the wire.
Moreover, the rolling secti-on comprises a set of mill rolls
for achieving a particular surface finish, designed to
produce predetermined shaped wire for enamel application.
Thus, in accordance with this invention, in an
installation for manufacturing rectangular enamelled magnet
wire, there is provided an in-line rolling and enamelling
system for transforming round bare magnet wire supplied
thereto into a magnet wire of predetermined rectangular
shape in the rolling section of the system, and enamelling
2081593
said rectangular wire in a single continuous operation
within the enamelling section of the system positioned in
tandem to the rolling section.
The novel method and installation of the present
invention essentially obviates most if not all of the
disadvantages of the conventional system, thus:
(a) Scrap
The novel method and installation will eliminate the
need for scrap allowance and subsequent scrap by producing
the exact amount of shaped conductor required by the
enamelling operation.
(b) Continuity of Production
The novel system will require only a few stems of
entering round wire to function.
(c) Remakes
The invention will eliminate the need for rolling mill
remakes since the in-line operation will match the
requirements of the enamelling machine.
(d) Brazes
The in-line system utilizes a simple cold pressure
weld on the entering round wire. A cold weld is as strong
as the parent metal and any scratches on the wire will be
rolled out, thereby eliminating test failures.
(e) Surface Ouality
The in-line mill can be provided with a set of mill
rolls having a surface finish which is designed to produce
the desired shaped wire for enamel application.
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(f) Wire Cleanliness
The new in-line rolling-enamelling system, being
continuous, supplies a clean, dirt and dust free
rectangular bare wire into the enamelling section of the
machine, eliminating test failures for these reasons.
(g) Wire Damage
The in-line mill eliminates wire damage by eliminating
the need to spool the rolled wire.
(h) Tension
The in-line mill, through a dancer arrangement,
delivers a smooth, consistent, controlled tension onto the
enamelling machine, produced by the enamel capstan pulling
the wire through the system.
(i) Size Variations
The in-line mill will not have periods of
inconsistency producing size variations, because it reaches
equilibrium in a few seconds.
(j) Productivity
Productivity is increased because of elimination of a
separate stage in the overall process, with consequent
reduction in labour requirements.
The invention will now be described with reference to
the accompanying drawings, in which:
Fig. 1 is a schematic representation, in perspective,
of the conventional enamelled magnet wire manufacturing
practice and is labelled "PRIOR ART"; and
Fig. 2 is a schematic representation, in perspective,
of the preferred embodiment of an installation in
accordance with the present invention.
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Referring to Fig. 1, the PRIOR ART or conventional
system for manufacturing rectangular magnet core comprises
a rod shaving machine 10 into which continuous cast and
rolled rod 11 is fed from 4500 kg coils 12. The shaving
5 operation produces a bright, clean surface rod 13 which is
wound onto stems 14 for subsequent drawing. The drawing of
the shaved rod 13 is carried out on a rod breakdown machine
15 where the shaved rod is drawn to a bare round wire 16 of
desired size, which is wound on reels 17 for subsequent
rolling.
The round wire 16 is then transferred to the rolling
station and fed from reels 17 into a rolling mill 18 in
which it is rolled to a wire 19 of predetermined
rectangular size. The rolling operation is controlled by
the control panel 20 and once the bare rectangular wire 19
of desired size is produced, it is wound onto reels 21 and
stored for enamelling. The reels 21 are then transferred to
the enamelling station 22 wherein the rectangular wire 19
is first fed into an annealer 23, then goes through a
cooling zone 24 and then through the enamel oven 25 where
the enamel coats are applied in a continuous process until
the desired thickness of insulation is achieved. The
produced enamelled magnet wire 26 is drawn by a capstan 27
and wound onto reels 28 which are shipped to the customer.
As is obvious from the above description, the
conventional system comprises four distinct and separate
operations, namely: (a) shaving; (b) drawing; (c) rolling;
and (d) enamelling.
B
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The installation in accordance which the present
invention is illustrated in Fig. 2 in which the rod shaving
machine 30 is fed with rod 31 from coil 32 where it is
shaved in a similar manner as in the conventional operation
to form a shaved rod 33 with a bright, clean surface,
which is wound onto stems 34 for subsequent drawing. The
shaved rod is then drawn on a rod breakdown machine 35 to
a bare round wire 36 of desired size and then, unlike the
conventional process where 30" reels are used, the wire is
coiled onto stems 37 for the in-line rolling and enamelling
process. From stems 37 the round wire 36 is fed into the
in-line rolling-enamelling system 38 comprising, in tandem,
a rolling section 39 and an enamelling section 40. In the
rolling section 39 the round wire 36 is rolled into a
rectangular wire 41 which then passes through the annealer
42 where it is annealed prior to enamelling. Then the
annealed wire is cooled in the cooling zone 43 and then
passes through the enamel oven 44 where the enamel coats
are applied until the desired thickness of insulation is
achieved. Then the enamelled wire, which is drawn by enamel
capstan 45, is wound on reels 46 which are shipped to the
customer. The enamel capstan 45 controls the tension and
the speed of the wire in the rolling - enamelling system 38
and a dancer arrangement is provided in the rolling section
39 for maint~i ni ng the required speed in said rolling
section 39 relative to the speed of the enamelling section
40. Also there is provided a self-contained lubrication
unit within the rolling section 39 to lubricate the wire
being rolled.
This novel arrangement is particularly suitable for
use with a "mini" rolling mill which has been designed for
continuous operation periods of 12 months between
maintenance services or roll changes. Such unit is modular
and consists of two high powered mill stands 39a and 39b
with a powered edger unit 47 between the mill stands. It is
controlled by control panels 48. The drive of the mill is
usually specifically sized for small reductions and is
accurately co-ordinated, through a dancer arrangement, with
the enamel machine capstan 45.
The method and installation in accordance with the
present invention operate approximately 50% faster than
conventional systems and eliminate approximately 20% of the
manufacturing cost. As already discussed, losses caused by
set-up, run to length and bare wire related quality
problems are significantly reduced. However, the novel
system may not produce very satisfactory results with wires
of large width and/or thickness for which the conventional
system may still be the best process.
It should be understood that this invention is not
limited by the preferred embodiment described and
illustrated herein and that obvious modifications or
adaptations may readily be carried out by a person skilled
in the art. The scope of the invention should, therefore,
only be construed by reference to the appended claims.
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