CA1219420A - Method and apparatus for manufacturing magnet wire - Google Patents
Method and apparatus for manufacturing magnet wireInfo
- Publication number
- CA1219420A CA1219420A CA000496799A CA496799A CA1219420A CA 1219420 A CA1219420 A CA 1219420A CA 000496799 A CA000496799 A CA 000496799A CA 496799 A CA496799 A CA 496799A CA 1219420 A CA1219420 A CA 1219420A
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- conductor
- die
- coated
- coating
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Abstract
A magnet wire consisting of a conductor and an essentially concentric continuous coating thereon. Wherein the coating has been applied to a desired thickness in a single pass. The conductor having been passed through a chamber comprising a stationary entrance die and an exit die the chamber being filled with a heated flowable coating material under pressure, with the conductor centered in a throat portion of the exit die.
Description
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~AC~G20UND OF ~HE I~VENTION
_, . . .
Th~ invention relates to magnet ~ire and a method and apparatus for manufacturing magnet wire, and more particularly/ to a method and apparatus for applying a coating of flowable resin material on a continuously moving filament to a desired thickness in a single pass.
Magnet wire has been conventionally manufactured by passing a bare copper or aluminum conductor or a previously insulated copper or aluminum conductor through a bath of liquid enamel (a solution of resin material in a solvent thereof) and through an oven for driving off the solvent from the enamel and/or curing the resin, leaving a resin coat on the conductor.
The application of a coat of material to a filament . . , ~ .
from solution accounts for all of the magnet wire manufactured today. While some materials using today's technology can only be applied from solution, the cost of the solvent expended in applying resin materials from solution is usually significant. The machinery used in this process is also higly complex and expensive, although the machinery cost is usually not a factor since most of such machinery has been in use for a considerable number of yearsO Still, the original cost of such machinery is significant for new installations.
In addition to the cost of machinery and the solvent expended by such a process, there is the cost of providing and maintaining pollution control equipment;
since recently both Federal and State laws have required that the oven stack gases of such machines be essentially stripped of solvent before exhausting the gases to the atmosphere. While various methods of - 3 ~
r~ ~ 2~%~
burning the vaDorized solv~-nt and/or re~claiming the solvent have been pro?osed, ~11 such methods result in further expense to the manufacturer.
Additionally, the application of a layer of material to a filament from solution usually requires several successive coats in order to result in a concentric coat of a desired thickness. For example, six coats may be required for a 3 mil coating, although in specific applications as many as 24 coats have been required. Also, multiple coats of certain materiais cannot be applied successfully from solution due to a lack of good adhesion and wetting between coats.
It therefore has been desirable for some time to provide an improved method of manufacturing magnet wire which eliminates the use of solvent. Also, it would be additionally highly desirble to provi~e an improved method of manufacturing magnet wire which would utilize an apparatus of simple design. Also, it would be highly desirable to provide a method of manufacturing magnet wire which would allow the wire to be drawn, coated and spooled in a continuous operation; conventionally the wire is drawn, annealed if necessary, spooled; and then coated and spooled again for shipment. Additionally, it would be highly desirable to provide a method and apparatus which can successfully apply multiple layers of materials which have heretofore not been possible.
Finally, it would be highly desirable to provide an improved method and apparatus for manufacturing magnet wire which would not require the use of solvent or pollution control apparatus, or be limited to materials requiring an oven cure, or require multiple coats to obtain a coating of the required continuity and concentricity.
` ' ~Z~L~420 ~ ??-~ ~ coâtin9s of ~esinous ;raterial by e~tr~sion is su~stlntially less com~on than apply`ing coatings from sOlUtion, ~ince conventional extrusion processes are extremel~ ited. Coatings of 4 mils and less are either ext.e~ely difficult to apply or impossible to apply by conventional extrusion processes. Also, the number of materials which are successfully applied by conventional extrusion processes are extremely limited.
~olyvinyl chloride, polyethylene, polypropylene and various elastomeric rubbers comprise 99% of the materials ap?lied by extrusion. These materials are not used in a true magnet wire application, i.e. an electrical winding, the turns of which are insulated to provide low voltage, mechanical, and thermal protection bet~een turns, and do not possess m,agnet wire properties. In contrast, these materials are conventionally used in lead wire or hooX-up wire applications which must protect against the full imput line voltage of an electrical device. Conventionally, extrusion is used in the production of only cables, building wire, and lead or hook-up wire.
~hile the apparatus used in conventional extrusion processes is relatively simple when compared to a conventional wire coating tower, and the extrusion process can be carried out continuously whereby the filament may be drawn, coated and spooled in a continuous operation, still, a conventional extrusion apparatus is not without problems. Conventional extruders include a centezing die, a material reservoir and a sizing die. The centering die mechanically centers the filament in the sizing die, the sizing die determines the exterior dimensions of the coated filament and the thickness of the coat applied to the 12~L~4Z~ , ~. , filament. The pri~ary problem ~ssociâted with extrusion apparatus is the .~ear on t~e centering die. Since the centering die used to cent:er the filament within the sizing die, the centering die rnust be finely adjusted to achieve a concentric coa~ing and must be replaced periodically due to the wear resulting from the contact between the filament and the die. Centering dies tend to be expensive even when made of hardened steel; but because of the wear tha~ occurs, diamond centering dies have been consiaered, but not widely used.
Therefore it ~ould be highly desirable to ?rovice an improved method and apparatus for T,an~facturing mmagnet wire which -~ould have all vf the benefits of an extrusion process but none of the disadvantages. Such a method and apparatus would lower the cost of the machinery to manufacture magnet wire and would eliminate the need for solvent, lower manufacturing costs, conserve raw materials and energy, eliminate the need for pollution control apparatus, require less expensive and simpler machinery than now is conventional, and allow for continuous operation from wire drawing to final shipment without being limited to materials from solution or oven cures.
SUMMARY O~ LHE INVENTION
It is therefore a primary object of this invention to provide an improved method and apparatus for manufacturing magnet wire.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire which does not require solutions of insulation material and therefore eliminates the~need for solvents, pollution control equipment or for ~ 94~:~ f reclaiming solvents from the ~,anufact~ring process, lowers the cost of ~T,anuf~cturing ~t leàst proportionally to the cost of solvent, and conserves energy at least to the degree that energy is required to remove solvents from the irsulation material.
It is also another object of this invention to provide an improved method and apparatus for manufacturing magnet wire which is not limited to the use of ir.sulation material solutions or materials reauiring c~ring after application.
It is another object of this invention to provide a me.hod and apparatus for manufacturing ~agnet wire which does not req~ire multiple coats to obtain the re~uired concentricity and/or continuity.
It is another object of this invention to provide an improved method and a?paratus for manufacturing magnet wire in which a coating material can be applied to a continuously moving elongated filament to a desired thickness in a single pass.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire by which magnet wire can be manufactured at speeds which are limited only by filament pay-off and take-~p devices.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire by which a coat of resin material may be applied to an elongated continuously moving filament to a desired single thickness in a single pass whereby the filament may be drawn or otherwise formed, coated and spooled in a continuous operation.
It is another object of this invention to provide an improved method and apparatus for manufacturing ~21~
magnet wire which completely eliminates or substantially reduces the use of solvents thereby eliminating the cost of solvents and the need Eor pollution control equipment or to reclaim the solvents from the manufacturing process.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire which completely eliminates the need of highly complex machinery or dies which experience high wear and must be replaced periodically.
It is another object of this invention to provide an improved method and apparatus of manufacturing magnet wire which has all of the advantages of a conventional extrusion process but is not limited in the thinness of the coating applied to the filament by such a process.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire having- all of the advantages of a conventional extru-sion process but none of the disadvantages.
In the broader aspects of the invention, there is provided a magnet wire comprising: an elongated conductor and an essentially concentric and continuous coating super-imposed on said conductor, said coating being applied to a desired thickness in a single pass, said coating being applied in accordance with the following steps:
a. passing said conductor through a stationary entrance dieat a speed in excess of 100 feet per minute, b. passing said conductor through a stationary exit die at a speed in excess of 100 feet per minute, said exit die having a throat portion, an entranceopening ~2:19~0 larger than said throat portion interconnected by a converging interior wall thereby defining a die cavity between said throat portion and said opening and said conductor and said wall, said entrance die and exit die defining and partially enclosing a die chamber there-between, said conductor in said dies being spaced from said dies, c. filling said die chamber with a flowable material including less than about 5% weight solvent at a temperature above the melting point thereof, d. raising the pressure of said material within said die chamber above atmospheric pressure, e. passing said conductor through said die chamber thereby applying said flowable material onto said conductor, f. centering said conductor in said throat portion of said exit die solely with said material in said die chamber, g. wiping the excess of said material from said conductor leaving an essentially concentric coat of said material on said conductor of a thickness meeting the requirements of ANSI/NEM~ Standards Publication No.
MW1000-1977.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be 19~ f bes~ ~nderstood by reference to the fellowiny description of the invention ~aken in conjunction with the accompanying drawinss wherein:
Fig. 1 is a perspective, fragmentary and diagramatic view of the apparatus of the invention;
Fig. 2 is a cross-sectional view of the coating die of the invention, taken substantially along the Section Line 2-2 of Fig. 1;
Fig. 3 is a front ?lan view of the coating die of the invention taken substantially along the Section Line 3-3 of Fig. l; and Fig. 4 is a cross-sectional vi2w of Lhe coating die of the invention taXen substantially along the Section Line 4-4 of Fig. 2.
DESCRIPTION OF A SPECIFIC Ei~BODIMENT
.
~PPARATUS
Referring to the drawings, and specifically Fig. 1, the apparatus of the invention will be described. The apparatus 10 generally consists of a filament pay-out device 12, a filament heater 14, a coating material dispenser 16, a coating die 18, a hardener 20, and a filament take-up device 22. As shown in Fig. 1, the filament 24 is broXen at 26, at 28, and at 30. At the filament break 26, when the apparatus of the invention is used to manufacture magnet wire, conventional wire drawing apparatus may be inserted. Thus, an oversized filament 24 may be reduced to the desired size by the drawing equipment prior to coating the filament. The filament heater 14 in a specific embodiment in which magnet wire is being manufactured by the apparatus of the invention may include an annealer whereby the ~219420 effects ~f drawing the wire or stretching t;~e ~ire T,ay be eliminated. In ot~er s?ecific embo~iments in which magnet wire is being "anufactured by the ap2aratus of the invention, additional coating dies 18 and hardeners 20 may be inserted at 28 such that successive coats of different coating materials may be applied to the ~ilament in a continuous manner.
The term "filament" is used herein for all strand ma.erials. Filaments thus include both copper and aluminum conductors and insulated copper and aluminum conductors which prior to the application of a coat of material by the apparatus and method of the invention have been lnsulated with a base coat of insulating material~ a tape of insulating material ei-her spirally or longitudinally wrapped on the conductor, or other conventional insulating materials, and other strand materials desirably coated. While the specific embodiments herein described primarily relate to the manufacture of magnet wire, the apparatus of the invention is thought to have utility in coating all sorts of filaments other than conductors or insulated conductors in the production of magnet wire.
The term "flowable material" is used herein for the general class of coating ma.erials applied by the method and apparatus of the invention. Again, while the specific embodiments herein described refer to meltable coating materials which can be hardened by cooling the material to ambient temperatures, other coating materials which are flowable at elevated temperatures and pressures are contemplated as being within the seneral class of materials which can be applied by the method and apparatus of the invention. These materials include materials which are initially flowable but later ~LZ~9420 , f hardened by curing or therrnosetting ~ne -aterial and also coating materials whicn ;,ay i~c~uce 1~ a a~u~ 5 by weight of solvent to render ~hem ~~'owarl -nd l,ter hardenable by driving the solvent from thP ma.erial. In the manufacture of magnet wire, several different materials can be applied by the method and a?pâratus of the invention. These include but are not limited to polyamides such as Nylon, pol~-ethylene terepnthalates, polybutylene terephthalates, polyethyle,es, poly?henylene sulfide, ?olycarbonates, ?ol~-prop~lenes, polyethersulfone, ?olyether imiaes, polyet:r,er etherketone, polysulphones, epoxvs, flurocarbor.s including ethylene-chlorotrifluoroethylene and hylene tetrafluoroethylene polyvinyi fo.m21, phenox~s, polyvinyl butyrol, polyamide-imide, polyesters and com~inations thereof.
The filament pay-out device 12 includes a spool 32 on which the filament 24 desirably coated is stored.
The spool 32 is mounted on spindle 34 of the pay-out device 12 so as to freely rotate in the direction of the arrow 36. 02eratively associated with the spool 32 is a brake 38 which restrains the rotation of the spool 32 as the filament 24 is being pulled therefrom by the take-up device 22 so as to prevent entanglements. In accordance with the method of the invention, it is highly possible that in a magnet wire manufacturing plant where conductors are being rolled, drawn or otherwise reduced in size to desirable conductor from ingots, the pay-out device 12 can be com?letely eliminated, since the remaining apparatus can be used to coat conductors continuously in a single pass as the conductor is supplied from such rolling and drawing apparatus. The reels 32 in this instance can be the reels upon which bare copper and aluminum conductors are now transported from the rolling and drawing operations to the magnet 0 f wire manufacturing alants. In all ins~r~ceJ wriere ~ho t~xe-up device 12 is elimir.at~d and rolling ~nd dr_~ing ?erations are substit~ted therefore, an anneâler is an essential part of the apparatus in order to eliminate the effects of working the conductor during the rolling and drawing operations.
Filament heater 14 is an essential part of the aP?aratUS OL the invention to be used in the perfGr~ance o- the method of the invention. A filament hea.er may be used solely to raise the tem?erature of the filament ?rir to the a??lication of the coating material or may be an annealer if har~d bare wire is used or to further reduce the effects of the aforementioned rolling and d-awing process, if required. Thus, in a specific embodiment, the filament heater 14 may consist of an annealer, or may consist of a filament heater. In the s?ecific filament heater embodiment 14 illustrated in Fig. 1, the filament heater comprises a resistance coil 40 being generally tubular in shape and having opposite 0~2n ends 42 and 44. The filament or conductor 24 is trai..ed bet~een the pay-out device 12 and the take-up device 22 through the coil 40. ~he filament heater 14 is also provided with a control 46 by which the temperature of the conductor 24 can be controlled. The filament heater 14 may also include a filament temperature measuring device such as a radiation pyrometer. Hereinafter in specific examples, the approximate wire temperatures reported herein are measured by such a device.
The ccating die 18 is illustrated in Figs. 1 through 4. The coating die 18 incl~des an entrance die 61, an exit die 62 and a die block 64. Entrance die 61 is mounted in the forward portion of die block 64 by 1219~20 f-screws 66. ~xit die 62 is ,"~n' ed in t~e .-arhdrd portion of die block 64 by screws 66'. ceDardting entrance die 61 and exit die 62 is an interior ?assage 65. Die block 54 is provided with heater bores 68 in which heaters 70 are positioned. In a specific embodiment, each heater 70 may be a tubular ca1rod heater. Additionally, the die block 64 is provided with a thermocouple bore 72 therein in which a thermocouple 74 ~shown only in Eig. 4) may be positioned.
F~rthermore, die block 64 is provi2ed ~ith a nozzle bore 75 therein to which the nozzle 54 of material applicator 16 is connected. Hereinafter, die temperatures are reported witn regard to specific examples; these die temperatures are measured by thermocoupie 74. Heaters 70 are connected by suitable conductors to a heater 76.
~eater 76 is provided with paired controls 78 whereby the temperature of the entrance die 61 and the exit die 62 each can be elevated above ambient te.~~erature ~for each die) and controlled, respectiveiy, as desired.
Referring to ~ig. 2, the entrance die 61 is shown in cross-section to include an entrance opening 80, a throat 82 and a converging interior wall 84 which interconnects the throat 82 and the entrance opening 80 of the entrance die 61. Entrance die 61 also has an exit op2ning 86 and a diveraing interior wall 88 interconnecting the throat 82 and the exit op~ning 86.
In a specific embodi~ent, the entrance die 61 can be constructed as illustrated in a two-piece fashion having a central piece 90 including a throat portion of harder and more wear-resistant material, and ex,erior piece 90' which includes both the e-ntrance opening 80 and the exit opening 86.
1,~ 2~:) f-The exit die 62 is -l~o s~own in cross-~ection to include an entrance o??ninq q2, a throat 93 and a converging interior wall 9~ whicn interconnects the throat 93 and the entrance opening 92 of the exit die 62. Converging interior wall 94 partially defines a die chamber 95 as will be mentioned hereinaf~er. Exit die 62 also has an exit opening 96 and a diverging interior wall 97 that interconnects the throat 93 and the e~it opening 96. In a specific ~mbo2iment, the exit die 62 can be constructed as illustrated in a two~?iece fashion having a central piece 98 including a Lhroat portion or harder and more wear resistant ma,erial than the exterior piece 98' which includes both the entrance opening 92 -nd exit opening 96.
In a speciric embodim?nt, the converging wall 84 and 94 define an angle A with conductor 24 of about 5 to about 40 degrees and throats 82 and 93 are tapered from converging ~alls 84 and 94 to diverging wall ~8 and 97 so as to define an angle with the conductor 24 of about 1 to about 2 degrees.
The flowable material applicator 16 has a chute 48 by which the material is supplied to the applicator, a material reservoir 50 in which the material may be stored, and a positive displacement pump 52 which pressurizes reservoir 50 and dispenses the flcwable material through a nozzle 54. ~hen using melts or other temperature responsive flowable materials, reservoir 50 is provided with a heater and a control device 56 by which the temperature of the naterial in the reservoir can be controlled. An additional control device 58 is associated with the positive displacement pump 52 to control the amount of flowable material passing through nozzle 54. In a specific embodiment, the fluid material 121~34ZO
a?plicator 16 ;nay ~e an extrusion ap?aratus havir.g the 'eatures above .'escri~ed. ~n t.,o~e ~p?lic2tiGns in which the flo~able .material is rendered more .lowable i~y the use of a small portion of sollJent, both the coating material and the solvent mav be fed into the applicator via the chute 48 and the reservoir 50 may be ?rovided with a mixing apparatus having associated therewith a separate control Ç0~ .
The central die cr.amber 95 is co;nple'elv detined by the diverging W311 88 of entrance die 61, the converging interior wall 94 o- exlt die 62, and the walls OL
interior passaae 65 of die block 54, Die chamber 95 is ?ositioned between ~hroat 82 and throat 93. The nozzle 54 is connected to no~zle bore 75 so that coating material in reservoir 50 may be injected into the central die chamber 99 under pressure by material applicator 16. The filament or conductor 24 is trained between the pay-out device 12 and the 'ake-up device 22 through the entrance die 61, the central die chamber 95, and the exit die 62, The hardener 20 functions to harden the coat of material on the filament or conductor 24 prior to spooling the ccated filament or maanet wire by the take-up device 22. The hardener 20 as illustrated inc'udes a trough 100 having opposite open ends 102 and 104. The trough is positioned such that the filament or conductor 24 can be trained to enter the open end 102, pass through the trouqh 100, and exit the open end 104.
Also as shown, the trough 100 is slGped downwardly toward the open end 102 and provided with a source of cooling fluid, such as water 108, adjacent open end 104 and a drain 110 adjacent open end 102. In many specific - :L6 -~Z1~20 ~ "
embodiments, a water quench utilizing ti1e structure of the hard-ener 20 is desired. In other specific embodiments, a quench is not required and thus, the cooling fluid is not used. In these embodiments, either a ~low of ambient air or refrigerated air (where available) is trained on the coated conductor or filament 24.
In specific embodiments in which multiple coats of dif-ferent materials are being applied to the filament or conductor 24 by successive spaced apart coating dies 18, the particular coating die used depends on the material to be applied and maybe either the coating die 18 having an entrance die 61 and an exit die 62 as disclosed herein or the coating die disclosed in United States Patent No. 4,393,809. The particular coating die used depends on the material to be applied. Each of the coating dies will have a material applicator 16 associated therewith and may have a hard-ener 20 associated therewith. The term "coating station" is used herein to refer to the assemblage of a material applicator 16, a coating die, and a hardener 20. In these embodiments, there will be a plurality of spaced apart coating stations between the pay-out device 12 and the take-up device 22.
The take-up device 22 in many respects is similar to the pay-out device 12. The take-up device 22 comprises a reel 32 on which the coated filament or conductor 24 is spooled for ship-ment. Thus, reels 32 may be the conventional spools on which coated filaments are conventionally shipped. Spools 32 are mount-ed for rotation on a spindle 34 so as to be driven in the direc-tion of the arrow 112. Operatively connected to the spool 32 is a spool driver 114 which drives the spool 32 and thereby pulls the filament or conductor 24 from the spool or reel 32 of the pay-out device 12.
THE :I_THOD
The method of the invention will r,ow be described.
~eference to Figs. 1 through 4 will be ref-rr2d to and the terms "flowable material" and "filament~ will be used as above defined. This description of the method of the invention will also specifically refer to the manufacture of magnet wire in a single p25S whereby the filament or conductor is drawn or otherwise formed, coated and s ooled in a continuous operation.
A continuous supply of the filament or conductor 24 is provided either by the pay-out device 12 as illustrated in Fig. 1 or from a rolling and drawin~
operation. If sup?lied from a rolling and drawing operation, the conductor 24 is alw~ys annealed to remove all effects of the rolling and drawing operation.
The filament or conductor 24 is then heated, if desired. Whether or not the rilament 24 is heated is dependant upon the coating material utilized and the wire properties desired. Thus/ the filament 24 may be heated by the heating device 14 to a temperature from about ambient temperature to about the decomposition temperature of the coating material. In most applications utilizing a melt or a heat-responsive flowable material in which the coat of material is desirably adhered to the filament or conductor 24, the filament or conductor is heated to a temperature from just below to about the melting point of the coating material. In most applications utilizing a melt or a heat-responsive flowable material in which the adhesion of the coat of material to the filament or conductor 24 is not required, the filament or conductor 24 is maintained from about the ambient temperature to slightly above the ambient temperature.
~ L9~0 The central die ch~mber 99 is then filled with a flowable ~iaterial, The flowable "ateriàl is stored in the material reservoir 50 at a flowable te.~?erature and pressure and is injected into the central die cnamber 99 by ap?licator 16. Once the central die chamber 99 has been filled with material, the flowable material contained therein will assume the pressure of the flowable coating material in the reservoir 5C. Pump 52 must have an adequate capacit~ to ,main~ain pressures up to about 2000 psi in reservoir 50 and cr.amber 99. 3y control 58, the res?onsiveness to pressure changes desired can be controlied. By controls 56 and 78, the tel!perature of the material in the reservoir 50 and c;.amber 99 can be controlled. The pressurized temperature of the flowable material in the central die chamber 99 must be carefully controlled for several reasons. First, if the pressure and/or temperature of the rlowable material in the central die chamber 99 is too great, the flowable coating material .-nay have the tendency to leak in significant quantities from the central die chamber 99 through throat 82, although the filament passing through throat 82 will allow operating pressures higher than that at which the flowable material will leak from opening 80 when the filament is stationary in openihg 80. Any significant leakage of flowable coating macerial from the die block 64 is not preferred. Secondly, both the pressure and temperature of the flowable material relate to the viscosity and/or flow characteristics of the flowable material, and must be such that the viscosity and/or flow characteristics of t;~e flowable material perforrns its centering function relative to the exit die 62 and produces a concentric ~2~947~0 coating as will be subse~ently discus~sed, wets the Cil~ment ~o be coated, ~nd suitably adheres to t~e filament. Thirdly, if the pressure and the tem?erature of the flowable material is too low, excessive filament stretching may occur rrom die 18 excessively resisting the movement of filament therethrough. It is for these reasons, that the applicator 16 is provided ~ith controls 56, 58, and 60.
The coating material is then applied to the filament or conductor 24 by passing the same through die 18. The coating mat2rial within the die chamber runctions to center the filament or conductor 24 ~ithin he throat portions 82 and 93 of dies 51 and 62. In all ins,ances known to the applicants whereln the central die chamber 99 is properly filled with coating material 115 and the temperature and pressure therein are properly controlled, filaments or cond~lctors 24 that are coated by the method and apparatus of the invention have a surprisingly concentric and continuous coat of coating material thereon. Conversely, in all situations in which the central die cha~ber 99 is not properly filled, and/or the tempera.ure and pressure therein is not properly controlled, a non-concentric and discontinuous coat of coating material is applied to the filament or conductor 24. Thus, the proper filling of the central die chamber 99 with coating material, the .-ontrol of the temperature and pressure of the coating material therein are essential to the method of the invention. Coating materials of various types have been successfully applied in accordance with the method of the invention by the above-described ap?aratus at viscosities from about 5,000 cps to 200,000 cps.
Applicant does not completely understand the actions of the flowable material within the central die chamber 99 which results in filaments having coatings of per-fect concentricity and continuity thereon. The coating material contained within the central die chamber 99 is believed to have movement adjacent the throat 83 of the exit die 62.
This movement may be somewhat similar to the movement of the annular or toroidal support 120 as described in United States Patent No. 4,393,809.
The throat portion 82 of the entrance die 61 prevents the flowable material within the die chamber 99 from leaking from die 18 through die 61. Depending upon the flow properties of the coating material, throat portion 82 will have a diameter of about 3 mil to about 15 mil larger than the diameter of filament 24.
The throat portion 93 of the exit die 62 regulates the thickness of the coat of coating material left on the filament or conductor 24 exiting the coating die 18.
The size of the throat portion 93 of the exit die 62 varies in accordance with the size of the filament or conductor 24, and the desired thickness of the coat of coating material to be applied thereon. The method of the invention has been sucess-fully used with filaments ranging from about 30 AW gauge to about 3/8" rod. Conductors of rectangular cross-sections and of other cross-sections can also be coated by the method and apparatus of the invention so that as long as the throat portions 82 and 93 of the entrance die 61 and exit die 62, respectively, can be provided in a geometrically similar shape. Coatings from about 1/2 mil to about 16 mils thick can be applied by the method of the invention. Depending upon the flow properties of the coating material, the throat portion 93 of the exit die ~ 94;2C) f 62 wil~ have a dia,ieter in most c_ses from a~out the desired diameter to about 2 mils laraer ~han thP desired diameter of the ccated filament or conductor 24 of magnet wire.
The coated filament or conductor 24 is then passed through the hardener 20 in order to harden the coating material thereon. ~hile the structure of the hardener 20 and the function thereof has been described hereinabove, it should be emphasized here that the operation of the hardener 20 depends greatly upon the coating material used. Either a water ~uench or an air quench may be utilized. Additionally, in those flowable ma'erials in which sma~l amounts of solvent are used to aid in the properties of the flowabl2 material, the hardener 20 may take the form of a filament heater 14, or a conventional curing oven (not shown). In all cases, the type of hardener 20 utili~ed and the temperature of the cooling liquid, air or other fluid utilized will depend both on the coating material and the speed at which the coated filament passes through the hardener 20.
The o?eration and function o' the take-up device 22 was described hereinabove. ~owever, the speed at which the take-up device 22 was driven W25 not mentioned. The driver 114 is not limited in any way by the method of the invention. The speed at which the driver 114 drives the spool 32 of the take-up device 22, in the embodiment illustrated in Fig. 1 utilizing both pay-out 12 and take-up 22 devices, is solely limited by the pay-out 12 and take-up 22 devices themselves when applying any of the ccating materials mentioned herein. '~'hen the pai~-out device 12 is eliminated and conventional rolling and drawing operations are substituted therefore, the speed at ~hich the take-up device 22 is driven by the ~ ~L2194~:0 f driver l14 is solely li~ited bv the '_Xe-up device 22, itself.
Specific e.Yamples in wnich conductors of ~arious sizes have been coated with coating ..,aterial such as above mentioned in accordance ~ith the method of this invention are tabulated in Table 1. Table l solely relates to the production of magnet wire. Table 1 tabulates all of the essential properties of the coating material and the conductor, all of the essential process conditions, and all of the essential physical and el-ctrical ?roperties of thè ,magnet -~ire produced in this specific ex mple in accordance with the method of the in~ention utiliz ng the apparatus described h~reinabove.
~ he magnet wire produced by the apparatus of the in~ention in accordance with the method of the invention meets all of the re~uirements of magnet wire made by other existing commercial processes. Table l ta~ulates the physical and electrical properties of various magnet wires manufactured in accGrdance with the method of the inJention utilizing the a??aratus of the in~-ention. A
surprising characteristic of all magnet wires made in accordance with the method of the in-~ention utilizing the a??aratus of the in~entiGn is the cGncer,tricity or the coating .~?plied to the conductor and the continuity thereof. ~oth the concentricity and continuity are a surprising result when compared to magnet wires made by other existing commercial processes, without regard to the means by which the conductor or fil~ment 24 is centered within the coating die 18. .~agnet wire produced by other commercial processes, such as the ~2~L13~
application of coatings from solution, periodically result in non-concentric coatings and non-continuous coatings. In fact, the continuity of coatings applied from solution is such that reliance upon a single coating of magnet wire insulation is un-heard of; and for this reason and others, multiple coatings are used as above mentioned. Magnet wire having a single coat is a commercial reality due to the concentricity and thickness of the coatings that can be applied by the apparatus and method of the invention.
The invention provides an improved method and appara-tus for applying coatings of a flowable material concentrically to a moving elongated filament. In the manufacture of magnet wire, the method and apparatus of the invention is an improve-ment over conventional methods of manufacturing magnet wire.
By the invention, insulation can be applied to a continuously moving elongated conductor, concentrically, to a desired thick-ness in a single pass. Materials can be applied by the inven-tion which can not be applied by the method and apparatus disclosed in United States Patent No. 4,393,809 above mentioned.
The speed is limited only by the pay-off and take-up devices.
The conductor can be drawn or otherwise formed, coated, and spooled in a continuous operation which completely eliminates or substantially reduces the use of solvents, thereby eliminat-ing the cost of solvents and the need for pollution control equipment. The apparatus of the invention completely eliminates the need for highly complex machinery or dies which experience high wear and must be replaced periodically. The improved method and apparatus of the invention has all of the advantages of 9~
a conventional extrusion process but nore of the disadvantages.
While there have been described above the principles of this invention in connected with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.
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~AC~G20UND OF ~HE I~VENTION
_, . . .
Th~ invention relates to magnet ~ire and a method and apparatus for manufacturing magnet wire, and more particularly/ to a method and apparatus for applying a coating of flowable resin material on a continuously moving filament to a desired thickness in a single pass.
Magnet wire has been conventionally manufactured by passing a bare copper or aluminum conductor or a previously insulated copper or aluminum conductor through a bath of liquid enamel (a solution of resin material in a solvent thereof) and through an oven for driving off the solvent from the enamel and/or curing the resin, leaving a resin coat on the conductor.
The application of a coat of material to a filament . . , ~ .
from solution accounts for all of the magnet wire manufactured today. While some materials using today's technology can only be applied from solution, the cost of the solvent expended in applying resin materials from solution is usually significant. The machinery used in this process is also higly complex and expensive, although the machinery cost is usually not a factor since most of such machinery has been in use for a considerable number of yearsO Still, the original cost of such machinery is significant for new installations.
In addition to the cost of machinery and the solvent expended by such a process, there is the cost of providing and maintaining pollution control equipment;
since recently both Federal and State laws have required that the oven stack gases of such machines be essentially stripped of solvent before exhausting the gases to the atmosphere. While various methods of - 3 ~
r~ ~ 2~%~
burning the vaDorized solv~-nt and/or re~claiming the solvent have been pro?osed, ~11 such methods result in further expense to the manufacturer.
Additionally, the application of a layer of material to a filament from solution usually requires several successive coats in order to result in a concentric coat of a desired thickness. For example, six coats may be required for a 3 mil coating, although in specific applications as many as 24 coats have been required. Also, multiple coats of certain materiais cannot be applied successfully from solution due to a lack of good adhesion and wetting between coats.
It therefore has been desirable for some time to provide an improved method of manufacturing magnet wire which eliminates the use of solvent. Also, it would be additionally highly desirble to provi~e an improved method of manufacturing magnet wire which would utilize an apparatus of simple design. Also, it would be highly desirable to provide a method of manufacturing magnet wire which would allow the wire to be drawn, coated and spooled in a continuous operation; conventionally the wire is drawn, annealed if necessary, spooled; and then coated and spooled again for shipment. Additionally, it would be highly desirable to provide a method and apparatus which can successfully apply multiple layers of materials which have heretofore not been possible.
Finally, it would be highly desirable to provide an improved method and apparatus for manufacturing magnet wire which would not require the use of solvent or pollution control apparatus, or be limited to materials requiring an oven cure, or require multiple coats to obtain a coating of the required continuity and concentricity.
` ' ~Z~L~420 ~ ??-~ ~ coâtin9s of ~esinous ;raterial by e~tr~sion is su~stlntially less com~on than apply`ing coatings from sOlUtion, ~ince conventional extrusion processes are extremel~ ited. Coatings of 4 mils and less are either ext.e~ely difficult to apply or impossible to apply by conventional extrusion processes. Also, the number of materials which are successfully applied by conventional extrusion processes are extremely limited.
~olyvinyl chloride, polyethylene, polypropylene and various elastomeric rubbers comprise 99% of the materials ap?lied by extrusion. These materials are not used in a true magnet wire application, i.e. an electrical winding, the turns of which are insulated to provide low voltage, mechanical, and thermal protection bet~een turns, and do not possess m,agnet wire properties. In contrast, these materials are conventionally used in lead wire or hooX-up wire applications which must protect against the full imput line voltage of an electrical device. Conventionally, extrusion is used in the production of only cables, building wire, and lead or hook-up wire.
~hile the apparatus used in conventional extrusion processes is relatively simple when compared to a conventional wire coating tower, and the extrusion process can be carried out continuously whereby the filament may be drawn, coated and spooled in a continuous operation, still, a conventional extrusion apparatus is not without problems. Conventional extruders include a centezing die, a material reservoir and a sizing die. The centering die mechanically centers the filament in the sizing die, the sizing die determines the exterior dimensions of the coated filament and the thickness of the coat applied to the 12~L~4Z~ , ~. , filament. The pri~ary problem ~ssociâted with extrusion apparatus is the .~ear on t~e centering die. Since the centering die used to cent:er the filament within the sizing die, the centering die rnust be finely adjusted to achieve a concentric coa~ing and must be replaced periodically due to the wear resulting from the contact between the filament and the die. Centering dies tend to be expensive even when made of hardened steel; but because of the wear tha~ occurs, diamond centering dies have been consiaered, but not widely used.
Therefore it ~ould be highly desirable to ?rovice an improved method and apparatus for T,an~facturing mmagnet wire which -~ould have all vf the benefits of an extrusion process but none of the disadvantages. Such a method and apparatus would lower the cost of the machinery to manufacture magnet wire and would eliminate the need for solvent, lower manufacturing costs, conserve raw materials and energy, eliminate the need for pollution control apparatus, require less expensive and simpler machinery than now is conventional, and allow for continuous operation from wire drawing to final shipment without being limited to materials from solution or oven cures.
SUMMARY O~ LHE INVENTION
It is therefore a primary object of this invention to provide an improved method and apparatus for manufacturing magnet wire.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire which does not require solutions of insulation material and therefore eliminates the~need for solvents, pollution control equipment or for ~ 94~:~ f reclaiming solvents from the ~,anufact~ring process, lowers the cost of ~T,anuf~cturing ~t leàst proportionally to the cost of solvent, and conserves energy at least to the degree that energy is required to remove solvents from the irsulation material.
It is also another object of this invention to provide an improved method and apparatus for manufacturing magnet wire which is not limited to the use of ir.sulation material solutions or materials reauiring c~ring after application.
It is another object of this invention to provide a me.hod and apparatus for manufacturing ~agnet wire which does not req~ire multiple coats to obtain the re~uired concentricity and/or continuity.
It is another object of this invention to provide an improved method and a?paratus for manufacturing magnet wire in which a coating material can be applied to a continuously moving elongated filament to a desired thickness in a single pass.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire by which magnet wire can be manufactured at speeds which are limited only by filament pay-off and take-~p devices.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire by which a coat of resin material may be applied to an elongated continuously moving filament to a desired single thickness in a single pass whereby the filament may be drawn or otherwise formed, coated and spooled in a continuous operation.
It is another object of this invention to provide an improved method and apparatus for manufacturing ~21~
magnet wire which completely eliminates or substantially reduces the use of solvents thereby eliminating the cost of solvents and the need Eor pollution control equipment or to reclaim the solvents from the manufacturing process.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire which completely eliminates the need of highly complex machinery or dies which experience high wear and must be replaced periodically.
It is another object of this invention to provide an improved method and apparatus of manufacturing magnet wire which has all of the advantages of a conventional extrusion process but is not limited in the thinness of the coating applied to the filament by such a process.
It is another object of this invention to provide an improved method and apparatus for manufacturing magnet wire having- all of the advantages of a conventional extru-sion process but none of the disadvantages.
In the broader aspects of the invention, there is provided a magnet wire comprising: an elongated conductor and an essentially concentric and continuous coating super-imposed on said conductor, said coating being applied to a desired thickness in a single pass, said coating being applied in accordance with the following steps:
a. passing said conductor through a stationary entrance dieat a speed in excess of 100 feet per minute, b. passing said conductor through a stationary exit die at a speed in excess of 100 feet per minute, said exit die having a throat portion, an entranceopening ~2:19~0 larger than said throat portion interconnected by a converging interior wall thereby defining a die cavity between said throat portion and said opening and said conductor and said wall, said entrance die and exit die defining and partially enclosing a die chamber there-between, said conductor in said dies being spaced from said dies, c. filling said die chamber with a flowable material including less than about 5% weight solvent at a temperature above the melting point thereof, d. raising the pressure of said material within said die chamber above atmospheric pressure, e. passing said conductor through said die chamber thereby applying said flowable material onto said conductor, f. centering said conductor in said throat portion of said exit die solely with said material in said die chamber, g. wiping the excess of said material from said conductor leaving an essentially concentric coat of said material on said conductor of a thickness meeting the requirements of ANSI/NEM~ Standards Publication No.
MW1000-1977.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be 19~ f bes~ ~nderstood by reference to the fellowiny description of the invention ~aken in conjunction with the accompanying drawinss wherein:
Fig. 1 is a perspective, fragmentary and diagramatic view of the apparatus of the invention;
Fig. 2 is a cross-sectional view of the coating die of the invention, taken substantially along the Section Line 2-2 of Fig. 1;
Fig. 3 is a front ?lan view of the coating die of the invention taken substantially along the Section Line 3-3 of Fig. l; and Fig. 4 is a cross-sectional vi2w of Lhe coating die of the invention taXen substantially along the Section Line 4-4 of Fig. 2.
DESCRIPTION OF A SPECIFIC Ei~BODIMENT
.
~PPARATUS
Referring to the drawings, and specifically Fig. 1, the apparatus of the invention will be described. The apparatus 10 generally consists of a filament pay-out device 12, a filament heater 14, a coating material dispenser 16, a coating die 18, a hardener 20, and a filament take-up device 22. As shown in Fig. 1, the filament 24 is broXen at 26, at 28, and at 30. At the filament break 26, when the apparatus of the invention is used to manufacture magnet wire, conventional wire drawing apparatus may be inserted. Thus, an oversized filament 24 may be reduced to the desired size by the drawing equipment prior to coating the filament. The filament heater 14 in a specific embodiment in which magnet wire is being manufactured by the apparatus of the invention may include an annealer whereby the ~219420 effects ~f drawing the wire or stretching t;~e ~ire T,ay be eliminated. In ot~er s?ecific embo~iments in which magnet wire is being "anufactured by the ap2aratus of the invention, additional coating dies 18 and hardeners 20 may be inserted at 28 such that successive coats of different coating materials may be applied to the ~ilament in a continuous manner.
The term "filament" is used herein for all strand ma.erials. Filaments thus include both copper and aluminum conductors and insulated copper and aluminum conductors which prior to the application of a coat of material by the apparatus and method of the invention have been lnsulated with a base coat of insulating material~ a tape of insulating material ei-her spirally or longitudinally wrapped on the conductor, or other conventional insulating materials, and other strand materials desirably coated. While the specific embodiments herein described primarily relate to the manufacture of magnet wire, the apparatus of the invention is thought to have utility in coating all sorts of filaments other than conductors or insulated conductors in the production of magnet wire.
The term "flowable material" is used herein for the general class of coating ma.erials applied by the method and apparatus of the invention. Again, while the specific embodiments herein described refer to meltable coating materials which can be hardened by cooling the material to ambient temperatures, other coating materials which are flowable at elevated temperatures and pressures are contemplated as being within the seneral class of materials which can be applied by the method and apparatus of the invention. These materials include materials which are initially flowable but later ~LZ~9420 , f hardened by curing or therrnosetting ~ne -aterial and also coating materials whicn ;,ay i~c~uce 1~ a a~u~ 5 by weight of solvent to render ~hem ~~'owarl -nd l,ter hardenable by driving the solvent from thP ma.erial. In the manufacture of magnet wire, several different materials can be applied by the method and a?pâratus of the invention. These include but are not limited to polyamides such as Nylon, pol~-ethylene terepnthalates, polybutylene terephthalates, polyethyle,es, poly?henylene sulfide, ?olycarbonates, ?ol~-prop~lenes, polyethersulfone, ?olyether imiaes, polyet:r,er etherketone, polysulphones, epoxvs, flurocarbor.s including ethylene-chlorotrifluoroethylene and hylene tetrafluoroethylene polyvinyi fo.m21, phenox~s, polyvinyl butyrol, polyamide-imide, polyesters and com~inations thereof.
The filament pay-out device 12 includes a spool 32 on which the filament 24 desirably coated is stored.
The spool 32 is mounted on spindle 34 of the pay-out device 12 so as to freely rotate in the direction of the arrow 36. 02eratively associated with the spool 32 is a brake 38 which restrains the rotation of the spool 32 as the filament 24 is being pulled therefrom by the take-up device 22 so as to prevent entanglements. In accordance with the method of the invention, it is highly possible that in a magnet wire manufacturing plant where conductors are being rolled, drawn or otherwise reduced in size to desirable conductor from ingots, the pay-out device 12 can be com?letely eliminated, since the remaining apparatus can be used to coat conductors continuously in a single pass as the conductor is supplied from such rolling and drawing apparatus. The reels 32 in this instance can be the reels upon which bare copper and aluminum conductors are now transported from the rolling and drawing operations to the magnet 0 f wire manufacturing alants. In all ins~r~ceJ wriere ~ho t~xe-up device 12 is elimir.at~d and rolling ~nd dr_~ing ?erations are substit~ted therefore, an anneâler is an essential part of the apparatus in order to eliminate the effects of working the conductor during the rolling and drawing operations.
Filament heater 14 is an essential part of the aP?aratUS OL the invention to be used in the perfGr~ance o- the method of the invention. A filament hea.er may be used solely to raise the tem?erature of the filament ?rir to the a??lication of the coating material or may be an annealer if har~d bare wire is used or to further reduce the effects of the aforementioned rolling and d-awing process, if required. Thus, in a specific embodiment, the filament heater 14 may consist of an annealer, or may consist of a filament heater. In the s?ecific filament heater embodiment 14 illustrated in Fig. 1, the filament heater comprises a resistance coil 40 being generally tubular in shape and having opposite 0~2n ends 42 and 44. The filament or conductor 24 is trai..ed bet~een the pay-out device 12 and the take-up device 22 through the coil 40. ~he filament heater 14 is also provided with a control 46 by which the temperature of the conductor 24 can be controlled. The filament heater 14 may also include a filament temperature measuring device such as a radiation pyrometer. Hereinafter in specific examples, the approximate wire temperatures reported herein are measured by such a device.
The ccating die 18 is illustrated in Figs. 1 through 4. The coating die 18 incl~des an entrance die 61, an exit die 62 and a die block 64. Entrance die 61 is mounted in the forward portion of die block 64 by 1219~20 f-screws 66. ~xit die 62 is ,"~n' ed in t~e .-arhdrd portion of die block 64 by screws 66'. ceDardting entrance die 61 and exit die 62 is an interior ?assage 65. Die block 54 is provided with heater bores 68 in which heaters 70 are positioned. In a specific embodiment, each heater 70 may be a tubular ca1rod heater. Additionally, the die block 64 is provided with a thermocouple bore 72 therein in which a thermocouple 74 ~shown only in Eig. 4) may be positioned.
F~rthermore, die block 64 is provi2ed ~ith a nozzle bore 75 therein to which the nozzle 54 of material applicator 16 is connected. Hereinafter, die temperatures are reported witn regard to specific examples; these die temperatures are measured by thermocoupie 74. Heaters 70 are connected by suitable conductors to a heater 76.
~eater 76 is provided with paired controls 78 whereby the temperature of the entrance die 61 and the exit die 62 each can be elevated above ambient te.~~erature ~for each die) and controlled, respectiveiy, as desired.
Referring to ~ig. 2, the entrance die 61 is shown in cross-section to include an entrance opening 80, a throat 82 and a converging interior wall 84 which interconnects the throat 82 and the entrance opening 80 of the entrance die 61. Entrance die 61 also has an exit op2ning 86 and a diveraing interior wall 88 interconnecting the throat 82 and the exit op~ning 86.
In a specific embodi~ent, the entrance die 61 can be constructed as illustrated in a two-piece fashion having a central piece 90 including a throat portion of harder and more wear-resistant material, and ex,erior piece 90' which includes both the e-ntrance opening 80 and the exit opening 86.
1,~ 2~:) f-The exit die 62 is -l~o s~own in cross-~ection to include an entrance o??ninq q2, a throat 93 and a converging interior wall 9~ whicn interconnects the throat 93 and the entrance opening 92 of the exit die 62. Converging interior wall 94 partially defines a die chamber 95 as will be mentioned hereinaf~er. Exit die 62 also has an exit opening 96 and a diverging interior wall 97 that interconnects the throat 93 and the e~it opening 96. In a specific ~mbo2iment, the exit die 62 can be constructed as illustrated in a two~?iece fashion having a central piece 98 including a Lhroat portion or harder and more wear resistant ma,erial than the exterior piece 98' which includes both the entrance opening 92 -nd exit opening 96.
In a speciric embodim?nt, the converging wall 84 and 94 define an angle A with conductor 24 of about 5 to about 40 degrees and throats 82 and 93 are tapered from converging ~alls 84 and 94 to diverging wall ~8 and 97 so as to define an angle with the conductor 24 of about 1 to about 2 degrees.
The flowable material applicator 16 has a chute 48 by which the material is supplied to the applicator, a material reservoir 50 in which the material may be stored, and a positive displacement pump 52 which pressurizes reservoir 50 and dispenses the flcwable material through a nozzle 54. ~hen using melts or other temperature responsive flowable materials, reservoir 50 is provided with a heater and a control device 56 by which the temperature of the naterial in the reservoir can be controlled. An additional control device 58 is associated with the positive displacement pump 52 to control the amount of flowable material passing through nozzle 54. In a specific embodiment, the fluid material 121~34ZO
a?plicator 16 ;nay ~e an extrusion ap?aratus havir.g the 'eatures above .'escri~ed. ~n t.,o~e ~p?lic2tiGns in which the flo~able .material is rendered more .lowable i~y the use of a small portion of sollJent, both the coating material and the solvent mav be fed into the applicator via the chute 48 and the reservoir 50 may be ?rovided with a mixing apparatus having associated therewith a separate control Ç0~ .
The central die cr.amber 95 is co;nple'elv detined by the diverging W311 88 of entrance die 61, the converging interior wall 94 o- exlt die 62, and the walls OL
interior passaae 65 of die block 54, Die chamber 95 is ?ositioned between ~hroat 82 and throat 93. The nozzle 54 is connected to no~zle bore 75 so that coating material in reservoir 50 may be injected into the central die chamber 99 under pressure by material applicator 16. The filament or conductor 24 is trained between the pay-out device 12 and the 'ake-up device 22 through the entrance die 61, the central die chamber 95, and the exit die 62, The hardener 20 functions to harden the coat of material on the filament or conductor 24 prior to spooling the ccated filament or maanet wire by the take-up device 22. The hardener 20 as illustrated inc'udes a trough 100 having opposite open ends 102 and 104. The trough is positioned such that the filament or conductor 24 can be trained to enter the open end 102, pass through the trouqh 100, and exit the open end 104.
Also as shown, the trough 100 is slGped downwardly toward the open end 102 and provided with a source of cooling fluid, such as water 108, adjacent open end 104 and a drain 110 adjacent open end 102. In many specific - :L6 -~Z1~20 ~ "
embodiments, a water quench utilizing ti1e structure of the hard-ener 20 is desired. In other specific embodiments, a quench is not required and thus, the cooling fluid is not used. In these embodiments, either a ~low of ambient air or refrigerated air (where available) is trained on the coated conductor or filament 24.
In specific embodiments in which multiple coats of dif-ferent materials are being applied to the filament or conductor 24 by successive spaced apart coating dies 18, the particular coating die used depends on the material to be applied and maybe either the coating die 18 having an entrance die 61 and an exit die 62 as disclosed herein or the coating die disclosed in United States Patent No. 4,393,809. The particular coating die used depends on the material to be applied. Each of the coating dies will have a material applicator 16 associated therewith and may have a hard-ener 20 associated therewith. The term "coating station" is used herein to refer to the assemblage of a material applicator 16, a coating die, and a hardener 20. In these embodiments, there will be a plurality of spaced apart coating stations between the pay-out device 12 and the take-up device 22.
The take-up device 22 in many respects is similar to the pay-out device 12. The take-up device 22 comprises a reel 32 on which the coated filament or conductor 24 is spooled for ship-ment. Thus, reels 32 may be the conventional spools on which coated filaments are conventionally shipped. Spools 32 are mount-ed for rotation on a spindle 34 so as to be driven in the direc-tion of the arrow 112. Operatively connected to the spool 32 is a spool driver 114 which drives the spool 32 and thereby pulls the filament or conductor 24 from the spool or reel 32 of the pay-out device 12.
THE :I_THOD
The method of the invention will r,ow be described.
~eference to Figs. 1 through 4 will be ref-rr2d to and the terms "flowable material" and "filament~ will be used as above defined. This description of the method of the invention will also specifically refer to the manufacture of magnet wire in a single p25S whereby the filament or conductor is drawn or otherwise formed, coated and s ooled in a continuous operation.
A continuous supply of the filament or conductor 24 is provided either by the pay-out device 12 as illustrated in Fig. 1 or from a rolling and drawin~
operation. If sup?lied from a rolling and drawing operation, the conductor 24 is alw~ys annealed to remove all effects of the rolling and drawing operation.
The filament or conductor 24 is then heated, if desired. Whether or not the rilament 24 is heated is dependant upon the coating material utilized and the wire properties desired. Thus/ the filament 24 may be heated by the heating device 14 to a temperature from about ambient temperature to about the decomposition temperature of the coating material. In most applications utilizing a melt or a heat-responsive flowable material in which the coat of material is desirably adhered to the filament or conductor 24, the filament or conductor is heated to a temperature from just below to about the melting point of the coating material. In most applications utilizing a melt or a heat-responsive flowable material in which the adhesion of the coat of material to the filament or conductor 24 is not required, the filament or conductor 24 is maintained from about the ambient temperature to slightly above the ambient temperature.
~ L9~0 The central die ch~mber 99 is then filled with a flowable ~iaterial, The flowable "ateriàl is stored in the material reservoir 50 at a flowable te.~?erature and pressure and is injected into the central die cnamber 99 by ap?licator 16. Once the central die chamber 99 has been filled with material, the flowable material contained therein will assume the pressure of the flowable coating material in the reservoir 5C. Pump 52 must have an adequate capacit~ to ,main~ain pressures up to about 2000 psi in reservoir 50 and cr.amber 99. 3y control 58, the res?onsiveness to pressure changes desired can be controlied. By controls 56 and 78, the tel!perature of the material in the reservoir 50 and c;.amber 99 can be controlled. The pressurized temperature of the flowable material in the central die chamber 99 must be carefully controlled for several reasons. First, if the pressure and/or temperature of the rlowable material in the central die chamber 99 is too great, the flowable coating material .-nay have the tendency to leak in significant quantities from the central die chamber 99 through throat 82, although the filament passing through throat 82 will allow operating pressures higher than that at which the flowable material will leak from opening 80 when the filament is stationary in openihg 80. Any significant leakage of flowable coating macerial from the die block 64 is not preferred. Secondly, both the pressure and temperature of the flowable material relate to the viscosity and/or flow characteristics of the flowable material, and must be such that the viscosity and/or flow characteristics of t;~e flowable material perforrns its centering function relative to the exit die 62 and produces a concentric ~2~947~0 coating as will be subse~ently discus~sed, wets the Cil~ment ~o be coated, ~nd suitably adheres to t~e filament. Thirdly, if the pressure and the tem?erature of the flowable material is too low, excessive filament stretching may occur rrom die 18 excessively resisting the movement of filament therethrough. It is for these reasons, that the applicator 16 is provided ~ith controls 56, 58, and 60.
The coating material is then applied to the filament or conductor 24 by passing the same through die 18. The coating mat2rial within the die chamber runctions to center the filament or conductor 24 ~ithin he throat portions 82 and 93 of dies 51 and 62. In all ins,ances known to the applicants whereln the central die chamber 99 is properly filled with coating material 115 and the temperature and pressure therein are properly controlled, filaments or cond~lctors 24 that are coated by the method and apparatus of the invention have a surprisingly concentric and continuous coat of coating material thereon. Conversely, in all situations in which the central die cha~ber 99 is not properly filled, and/or the tempera.ure and pressure therein is not properly controlled, a non-concentric and discontinuous coat of coating material is applied to the filament or conductor 24. Thus, the proper filling of the central die chamber 99 with coating material, the .-ontrol of the temperature and pressure of the coating material therein are essential to the method of the invention. Coating materials of various types have been successfully applied in accordance with the method of the invention by the above-described ap?aratus at viscosities from about 5,000 cps to 200,000 cps.
Applicant does not completely understand the actions of the flowable material within the central die chamber 99 which results in filaments having coatings of per-fect concentricity and continuity thereon. The coating material contained within the central die chamber 99 is believed to have movement adjacent the throat 83 of the exit die 62.
This movement may be somewhat similar to the movement of the annular or toroidal support 120 as described in United States Patent No. 4,393,809.
The throat portion 82 of the entrance die 61 prevents the flowable material within the die chamber 99 from leaking from die 18 through die 61. Depending upon the flow properties of the coating material, throat portion 82 will have a diameter of about 3 mil to about 15 mil larger than the diameter of filament 24.
The throat portion 93 of the exit die 62 regulates the thickness of the coat of coating material left on the filament or conductor 24 exiting the coating die 18.
The size of the throat portion 93 of the exit die 62 varies in accordance with the size of the filament or conductor 24, and the desired thickness of the coat of coating material to be applied thereon. The method of the invention has been sucess-fully used with filaments ranging from about 30 AW gauge to about 3/8" rod. Conductors of rectangular cross-sections and of other cross-sections can also be coated by the method and apparatus of the invention so that as long as the throat portions 82 and 93 of the entrance die 61 and exit die 62, respectively, can be provided in a geometrically similar shape. Coatings from about 1/2 mil to about 16 mils thick can be applied by the method of the invention. Depending upon the flow properties of the coating material, the throat portion 93 of the exit die ~ 94;2C) f 62 wil~ have a dia,ieter in most c_ses from a~out the desired diameter to about 2 mils laraer ~han thP desired diameter of the ccated filament or conductor 24 of magnet wire.
The coated filament or conductor 24 is then passed through the hardener 20 in order to harden the coating material thereon. ~hile the structure of the hardener 20 and the function thereof has been described hereinabove, it should be emphasized here that the operation of the hardener 20 depends greatly upon the coating material used. Either a water ~uench or an air quench may be utilized. Additionally, in those flowable ma'erials in which sma~l amounts of solvent are used to aid in the properties of the flowabl2 material, the hardener 20 may take the form of a filament heater 14, or a conventional curing oven (not shown). In all cases, the type of hardener 20 utili~ed and the temperature of the cooling liquid, air or other fluid utilized will depend both on the coating material and the speed at which the coated filament passes through the hardener 20.
The o?eration and function o' the take-up device 22 was described hereinabove. ~owever, the speed at which the take-up device 22 was driven W25 not mentioned. The driver 114 is not limited in any way by the method of the invention. The speed at which the driver 114 drives the spool 32 of the take-up device 22, in the embodiment illustrated in Fig. 1 utilizing both pay-out 12 and take-up 22 devices, is solely limited by the pay-out 12 and take-up 22 devices themselves when applying any of the ccating materials mentioned herein. '~'hen the pai~-out device 12 is eliminated and conventional rolling and drawing operations are substituted therefore, the speed at ~hich the take-up device 22 is driven by the ~ ~L2194~:0 f driver l14 is solely li~ited bv the '_Xe-up device 22, itself.
Specific e.Yamples in wnich conductors of ~arious sizes have been coated with coating ..,aterial such as above mentioned in accordance ~ith the method of this invention are tabulated in Table 1. Table l solely relates to the production of magnet wire. Table 1 tabulates all of the essential properties of the coating material and the conductor, all of the essential process conditions, and all of the essential physical and el-ctrical ?roperties of thè ,magnet -~ire produced in this specific ex mple in accordance with the method of the in~ention utiliz ng the apparatus described h~reinabove.
~ he magnet wire produced by the apparatus of the in~ention in accordance with the method of the invention meets all of the re~uirements of magnet wire made by other existing commercial processes. Table l ta~ulates the physical and electrical properties of various magnet wires manufactured in accGrdance with the method of the inJention utilizing the a??aratus of the in~-ention. A
surprising characteristic of all magnet wires made in accordance with the method of the in-~ention utilizing the a??aratus of the in~entiGn is the cGncer,tricity or the coating .~?plied to the conductor and the continuity thereof. ~oth the concentricity and continuity are a surprising result when compared to magnet wires made by other existing commercial processes, without regard to the means by which the conductor or fil~ment 24 is centered within the coating die 18. .~agnet wire produced by other commercial processes, such as the ~2~L13~
application of coatings from solution, periodically result in non-concentric coatings and non-continuous coatings. In fact, the continuity of coatings applied from solution is such that reliance upon a single coating of magnet wire insulation is un-heard of; and for this reason and others, multiple coatings are used as above mentioned. Magnet wire having a single coat is a commercial reality due to the concentricity and thickness of the coatings that can be applied by the apparatus and method of the invention.
The invention provides an improved method and appara-tus for applying coatings of a flowable material concentrically to a moving elongated filament. In the manufacture of magnet wire, the method and apparatus of the invention is an improve-ment over conventional methods of manufacturing magnet wire.
By the invention, insulation can be applied to a continuously moving elongated conductor, concentrically, to a desired thick-ness in a single pass. Materials can be applied by the inven-tion which can not be applied by the method and apparatus disclosed in United States Patent No. 4,393,809 above mentioned.
The speed is limited only by the pay-off and take-up devices.
The conductor can be drawn or otherwise formed, coated, and spooled in a continuous operation which completely eliminates or substantially reduces the use of solvents, thereby eliminat-ing the cost of solvents and the need for pollution control equipment. The apparatus of the invention completely eliminates the need for highly complex machinery or dies which experience high wear and must be replaced periodically. The improved method and apparatus of the invention has all of the advantages of 9~
a conventional extrusion process but nore of the disadvantages.
While there have been described above the principles of this invention in connected with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of the invention.
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Claims (16)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A magnet wire comprising: an elongated conductor and an essentially concentric and continuous coating superimposed on said conductor, said coating being applied to a desired thickness in a single pass, said coating being applied in accordance with the following steps:
a. passing said conductor through a stationary entrance die at a speed in excess of 100 feet per minute, b. passing said conductor through a stationary exit die at a speed in excess of 100 feet per minute, said exit die having a throat portion, an entrance opening larger than said throat portion interconnected by a con-verging interior wall thereby defining a die cavity between said throat portion and said opening and said conductor and said wall, said entrance die and exit die defining and partially enclosing a die chamber therebetween, said conductor in said dies being spaced from said dies, c. filling said die chamber with a flowable material including less than about 5% weight solvent at at temperature above the melting point thereof, d. raising the pressure of said material within said die chamber above atmospheric pressure, e. passing said conductor through said die chamber thereby applying said flowable material onto said conductor, f. centering said conductor in said throat portion of said exit die solely with said material in said die chamber, g. wiping the excess of said material from said conductor leaving an essentially concentric coat of said material on said conductor of a thickness meeting the requirements of ANSI/NEMA Standards Publication No.
MW1000-1977.
a. passing said conductor through a stationary entrance die at a speed in excess of 100 feet per minute, b. passing said conductor through a stationary exit die at a speed in excess of 100 feet per minute, said exit die having a throat portion, an entrance opening larger than said throat portion interconnected by a con-verging interior wall thereby defining a die cavity between said throat portion and said opening and said conductor and said wall, said entrance die and exit die defining and partially enclosing a die chamber therebetween, said conductor in said dies being spaced from said dies, c. filling said die chamber with a flowable material including less than about 5% weight solvent at at temperature above the melting point thereof, d. raising the pressure of said material within said die chamber above atmospheric pressure, e. passing said conductor through said die chamber thereby applying said flowable material onto said conductor, f. centering said conductor in said throat portion of said exit die solely with said material in said die chamber, g. wiping the excess of said material from said conductor leaving an essentially concentric coat of said material on said conductor of a thickness meeting the requirements of ANSI/NEMA Standards Publication No.
MW1000-1977.
2. The coated conductor of Claim 1 wherein said conductor is chosen from the group consisting of bare copper and aluminum conductors, and coated copper and aluminum conductors.
3. The coated conductor of Claim 1 wherein said entrance die and exit die are held in a die block, said die block and said entrance and exit dies defining said die chamber, and wherein said filling step comprises passing said material through a passage in said die block, said passage fluidly connecting said die chamber with a material reservoir.
4. The coated conductor of Claim 1 wherein said wiping step includes the step of passing said conductor through said exit die, said exit die having a size relationship with the size of said conductor controlling the thickness of the coating material on said conductor.
5. The coated conductor of Claim 1 wherein said centering step includes the step of controlling the viscosity of said material within said die chamber.
6. The coated conductor of Claim 1 wherein said centering step includes the step of controlling the pressure of said material within said die chamber.
7. The coated conductor of Claim 1 wherein said flowable material is a heat softenable material, and said centering step includes the step of controlling the temperature of said dies.
8. The coated conductor of Claim 1 wherein said flowable material is a heat softenable material, and said centering step includes the step of controlling the temperature of said conductor.
9. The coated conductor of Claim 1 wherein said centering step includes the step of causing movement of said material within said die chamber.
10. The coated conductor of Claim 1 wherein said conductor is of a group consisting of bare copper and aluminum conductors, and insulated conductors having a base insulation previously applied.
11. The coated conductor of Claim 1 wherein said material is of the group consisting of Nylon, polyethylene terephthalates, polybutylene terephthalates, polyethylenes, polyphenylene sulfide, polycarbonates, polypropylenes, polyethersulfone, polyether imides, polyether etherketone, polysulphones, epoxys, fluorocarbons including ethylene-chlorotrifluoroethlene and ethlene tetrafluoroethylene, polyvinyl formal, phenoxys, polyvinyl butyrol, polyamide-imide, polyesters and combinations thereof.
12. The coated conductor of Claim 1 wherein said material in said die chamber has a viscosity from about 5,000 cps to about 200,000 cps.
13. The coated conductor of Claim 1 wherein said conductor is from about 30 AWG gauge to about 3/8" rod.
14. The coated conductor of Claim 1 wherein said centering step includes the step of controlling the pressure of said material within said die chamber.
15. The coated conductor of Claim 1 wherein said material pressure is below about 2000 psi.
16. The coated conductor of Claim 1 wherein said entrance die is small enough to prevent leakage of said material from said die chamber while said conductor is passing therethrough at said material pressure and large enough to allow said leakage when said conductor is stationary in said entrance die at said material pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000496799A CA1219420A (en) | 1983-09-01 | 1985-12-03 | Method and apparatus for manufacturing magnet wire |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000435917A CA1204570A (en) | 1983-09-01 | 1983-09-01 | Method and apparatus for manufacturing magnet wire |
| CA000496799A CA1219420A (en) | 1983-09-01 | 1985-12-03 | Method and apparatus for manufacturing magnet wire |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000435917A Division CA1204570A (en) | 1983-09-01 | 1983-09-01 | Method and apparatus for manufacturing magnet wire |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1219420A true CA1219420A (en) | 1987-03-24 |
Family
ID=4125998
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000435917A Expired CA1204570A (en) | 1983-09-01 | 1983-09-01 | Method and apparatus for manufacturing magnet wire |
| CA000496799A Expired CA1219420A (en) | 1983-09-01 | 1985-12-03 | Method and apparatus for manufacturing magnet wire |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000435917A Expired CA1204570A (en) | 1983-09-01 | 1983-09-01 | Method and apparatus for manufacturing magnet wire |
Country Status (1)
| Country | Link |
|---|---|
| CA (2) | CA1204570A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7973122B2 (en) | 2004-06-17 | 2011-07-05 | General Cable Technologies Corporation | Polyamideimide compositions having multifunctional core structures |
-
1983
- 1983-09-01 CA CA000435917A patent/CA1204570A/en not_active Expired
-
1985
- 1985-12-03 CA CA000496799A patent/CA1219420A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7973122B2 (en) | 2004-06-17 | 2011-07-05 | General Cable Technologies Corporation | Polyamideimide compositions having multifunctional core structures |
Also Published As
| Publication number | Publication date |
|---|---|
| CA1204570A (en) | 1986-05-20 |
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