US3757077A - S of focalized laser rays apparatus for cutting slivers of continuous textile filaments by mean - Google Patents

S of focalized laser rays apparatus for cutting slivers of continuous textile filaments by mean Download PDF

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Publication number
US3757077A
US3757077A US00126787A US3757077DA US3757077A US 3757077 A US3757077 A US 3757077A US 00126787 A US00126787 A US 00126787A US 3757077D A US3757077D A US 3757077DA US 3757077 A US3757077 A US 3757077A
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Prior art keywords
track
sliver
windows
length
track means
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US00126787A
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English (en)
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F Siclari
F Magnoni
G Bianucci
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SNIA Viscosa SpA
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SNIA Viscosa SpA
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
    • D01G1/00—Severing continuous filaments or long fibres, e.g. stapling
    • D01G1/02—Severing continuous filaments or long fibres, e.g. stapling to form staple fibres not delivered in strand form
    • D01G1/025—Severing continuous filaments or long fibres, e.g. stapling to form staple fibres not delivered in strand form by thermic means, e.g. laser
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/14—Working by laser beam, e.g. welding, cutting or boring using a fluid stream, e.g. a jet of gas, in conjunction with the laser beam; Nozzles therefor
    • B23K26/1462—Nozzles; Features related to nozzles

Definitions

  • This invention generally relates to the problem of cutting textile and in particular synthetic continuous filaments into more or less short fibres in order to obtain so called tuft fibres adapted for further spinning and twisting operations, as required for producing fibrous textile yarns.
  • all artificial and synthetic fibres are produced in the form of continuous filaments extruded through spinnerets and then suitably drawn or otherwise processed, said filaments being gathered and advanced in the form of slivers (wherein said filaments are arranged parallel and close to, but not connected with each other), consisting of a very large number (usually many thousand) of filaments.
  • slivers or more exactly all filaments thereof are cut into preestablished lengths to form said tuft fibres which are then forwarded to conventional processes in order to obtain a rove whereon spinning and twisting operations are carried out.
  • the most modern techniques for producing artificial and synthetic filaments allow the attainment of very high sliver feeding speeds, of the order of several hundred meters per minute, and a trend to further increase said speeds can also be noticed. Since the filaments to be converted into tuft fibres are to be cut into very short lengths (of about 40 mms for a so called cotton cut, and about 70-90 mms for a woollen cut), the cutting frequency may attain very high values, of the order of several thousand cuts per minute and therefore of many hundred cuts per second.
  • a cutting operation is carried-out on filament slivers by mechanical means and in particular by suitable shear blades or knives that act on the sliver in a point intermediate between two points thereof wherein the filaments are retained or anchored.
  • Such action is usually performed by engaging and advancing the sliver between counterrotating members, generally in the form of suitably grooved rollers, metal chains or the like.
  • the filaments are thus engaged between the sharp corners of slots or grooves of said rotary members, one or both of which may comprise edges of a resilient material in order to ensure the adherence and detainment of filaments.
  • an air stream or other suitable means draws away the thus obtained tuft fibres.
  • the artificial filaments and in particular the synthetic ones as e.g. polyester filaments may be rather hard and then cause a very quick wear of blade or knive cutting edges, which results in a necessity to frequently replace the cutting tools and thus to stop the cutting equipment.
  • said blades or knives may become further worn due to the possible presence of acidic components in the filaments, when obtained from spinning rayon or regenerated cellulose.
  • An object of this invention is to provide, in the field of cutting slivers consisting of a very high number of single filaments and advancing at very high linear speeds, a method by which already known drawbacks and restrictions of prior art mechanical cutting systems are wholly overcome.
  • a more specific object of this invention is to find and industrially carry-out'the scientific principle of obtaining a very high and strictly localized thermal action by means of focalized laser rays (coherent monochromatic light energy).
  • thermoplastic filament ends may stick with each other and this occurrence is not considered as harmful; on the contrary, at least from certain viewpoints said sticking action may be considered as suitable in that it stabilizes the cut fabric edges.
  • a laser radiation when focalized in an essentially rectangular window having a major side directed crosswise to the sliver feeding direction and longer than the sliver width, as well as a minor side of a few microns only, and when said radiation is applied in the form of pulses having a pulse duration of a few millionth of second, is able to sharply and thoroughly I cut all filaments in the sliver, with a complete removal of material in front of said window and without causing undesirable melting phenomena in the zones adjacent to the cut as well as welding phenomena on the fibres closely contacting with one another during said cutting operation.
  • the method according to this invention consists in feeding a filament sliver at a required linear speed, between two counter-rotating feeding elements, and in particular between parallel and closely adjacent lengths of two endless chain tracks, at least one of which is formed with windows uniformly spaced at intervals equal to the length or to a submultiple of the length of fibres into which the filaments are to be cut, and in directing on said sliver a pulsed laser ray focalized toward the plane wherein the sliver is lying, in synchronism with the passage of said windows across the point wherein the sliver feeding direction intersects the direction of said laser ray.
  • Laser pulses synchronized with the passage of said windows can be obtained by placing a suitable intercepting device, e.g. in the form of a suitably perforated rotating disk, in the path of rays continuously emitted by a generator, or preferably by providing a pulse generator having a frequency synchronized with that of said cutting cycle, and more precisely a frequency as follows:
  • a laser ray source that emits a radiation having a wavelength corresponding to one of the ab sorption bands of the polymer forming the filaments to be cut, and preferably corresponding to the more relevant absorption band.
  • Said absorption bands are generally very narrow and it has been ascertained that changes in the laser ray wavelength, even of fractions of microns, may considerably affect the cut efficiency.
  • the cut operation may be performed at a high speed and without any harmful fibre sticking.
  • said method also comprises to blow an inert gas and in particular nitrogen against sliver points directly upstream and downstream the cut line, in order to ensure an instantaneous heat removal from the filament and fibre zones directly adjacent to said out (wherein the filament material is melted or more exactly volatilized), as well as to ensure that the cutting operation be made in an environment wherein no oxidation phenomena due to the presence of atmospheric oxygen may occur.
  • FIG. 1 is a perspective view of the whole equipment
  • FIG. 2 is an enlarged detailed view of the cutting zone of said equipment.
  • the shown equipment comprises a laser generator, generally designated by the numeral and operating to emit a ray through a window 12, having a few millimeters light diameter, in a direction as indicated by the dot and dash line 14.
  • Said generator comprises suitable focalizing systems well known in the art and therefore not shown, by which said laser ray is focalized or concentrated at a pre-established focal length in the form of a flat and lengthened beam, directed toward a rectangular window 16 (see FIG. 2), having a major side slightly longer than the width of the sliver 18 to be cut.
  • the sliver 18 is fed at a linear speed V between two counter-rotating endless chain tracks 20 and 22 having parallely fitted sections located at a right angle in respect to the laser ray direction 14.
  • Said endless chain tracks are guided at a linear speed V by pairs of pulleys 24, 26 and 28 and 30, respectively, at least one pulley of each pair being suitably driven.
  • Said tracks 20 and 22 may be in the form of metal bands or non-metallic material bands, and are supported in such a manner as to show parallel and approached lengths 20 and respectively 22', leaving a space therebetween to ensure the engagement of sliver 18 in a suitable planar arrangement for cutting operations thereon.
  • At least the track 20 is formed with a plurality of windows 32, having a width and a height greater than the corresponding dimensions of window 16 wherein said laser ray is focalized, said windows 32 being spaced at intervals D equal to the greatest common factor between the lengths of tuft fibres into which the filaments of sliver 18 are to be cut.
  • the whole equipment is assembled in such a way that the vertical lengths of track 20, which obviously run in opposite directions, show aligned windows 32 when crossing the laser ray.
  • said laser ray is pulsed (or pulsatorily intercepted) in synchronism with the passage of said windows 32 in alignment relationship with said ray direction 14.
  • the whole equipment is obviously assembled and pre-set in such a manner that the plane wherein said sliver l8 lies, between said approached track lengths, is coincident with the plane wherein the laser ray is focalized within said essentially rectilinear window 16.
  • the sliver portions that are left uncovered by said windows 32 are struck by the laser ray, as focalized in 16 and are accurately and sharply sheared across a minimum height, owing to very small height of window 16 wherein the ray is focalized, as well as to very short pulse duration.
  • said laser pulses are synchronized at a frequency corresponding to the passage of windows 32, the filaments of sliver 18 are cut into tuft fibres having a length D.
  • said pulses shall be synchronized at a frequency such as to operate only when a corresponding multiple of windows 32 is passed across said direction 14.
  • the laser ray energy in excess to that absorbed for the volatilization of filaments may be taken-up by the downstream located track length 22.
  • it can be formed with windows and a suitably cooled screen is then fitted behind the same and in the laser ray direction 14 to take-up said residual energy.
  • the equipment comprises further a device 34, that is connected to a suitable source of pressurized nitrogen and is formed with slit nozzles 36 and 38 through which blade-shaped nitrogen jets are directed against the sliver 18, above and below the striking point of said laser ray.
  • the equipment comprises also means wherein the tuft fibres are collected when discharged in a direction F from said feeding tracks, such means being diagrammatically exemplified by a collecting container 40; as well as means for cooling said tracks, safety and protection means for the zone traversed by said laser ray, and so on.
  • a sliver formed by 10,000 polyester filaments each having a count of 1.5 deniers and thus with a total sliver count of 15,000 deniers was cut in tuft fibres.
  • Said sliver was fed at a speed of 500 m/min. and cotton-cut sheared.
  • the track 20 was fonned with windows at intervals D or 40 mms, and laser pulses having a wavelength of about 8 microns and focalized as in 16 over a width of 20 mms were sent therethrough at a frequency of about 208 pulses per second in such a manner that the sliver 18 was struck approximately at the center of each window 32.
  • Another sliver was similarly sheared into woolen-cut tuft fibres mm and mm long by means of laser rays having a frequency equal to a half and respectively to a third of the above stated one. A sharp and constant cutting action was obtained, with a very small portion of welded fibres that is due to faults in the previously carried-out filament drawing and thermosetting operations.
  • Apparatus for cutting a sliver of textile filaments into textile tufts comprising first and second endless track means, means mounting said track means for rotation, at least a portion of said first track means being positioned in a plane parallel to and adjacent at least a portion of said second track means for holding a length of sliver therebetween, means for rotating said track means, said means for rotating said track means moving said portions of said track means in the same direction, whereby said length of sliver is also moved in said same direction in a plane parallel to said first mentioned plane; said first track having a plurality of win dows therein for exposing a portion of said sliver, each of said windows having a width larger than that of said sliver and a height of a few microns so that the entire width of said portion of said sliver can be exposed in said windows; means for generating a beam of laser radiation positioned adjacent said track means; and means for focusing said beam onto a part of said first track means where said portion of said track means is adjacent
  • Apparatus as claimed in claim 1 including means for emitting said beam of laser radiation in pulses having a pulse duration shorter than one thousandth of a second.
  • Apparatus as claimed in claim 3 comprising means for blowing a jet of an oxidation preventing gas towards points located directly upstream and downstream of the part of said first track struck by said laser beam.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Mechanical Engineering (AREA)
  • Textile Engineering (AREA)
  • Treatment Of Fiber Materials (AREA)
  • Preliminary Treatment Of Fibers (AREA)
  • Laser Beam Processing (AREA)
US00126787A 1970-03-26 1971-03-22 S of focalized laser rays apparatus for cutting slivers of continuous textile filaments by mean Expired - Lifetime US3757077A (en)

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IT2249370 1970-03-26

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US3757077A true US3757077A (en) 1973-09-04

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US (1) US3757077A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
BE (1) BE764751A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2114483B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
FR (1) FR2085142A5 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1312188A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
NL (1) NL7007649A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4302654A (en) * 1979-06-11 1981-11-24 Bennett William T Microperforation of cigarette tipping paper by use of laser beam
US5069735A (en) * 1990-06-04 1991-12-03 Milliken Research Corporation Apparatus for producing sealed edge knit wiping cloths
DE4301575A1 (en) * 1992-01-24 1993-07-29 Fraunhofer Ges Forschung Laser cutting of wire and strip - over hollow rotating cylinder housing a focussing unit
US5878464A (en) * 1996-04-16 1999-03-09 White; Homer S. Apparatus and method for converting continuous tow fibers into a staple length
WO1999059766A1 (en) * 1998-05-18 1999-11-25 Lear Corporation Laser fiber chopper

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DD95521A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) * 1972-02-04 1973-02-12
EP0097618A1 (fr) * 1982-06-17 1984-01-04 Battelle Memorial Institute Procédé pour sectionner, par laser, un filament ou une fibre textile en matériau thermoplastique
DE4100925C2 (de) * 1991-01-15 1996-08-01 Poly Id Ag Verfahren zur Behandlung von Faserstücken

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4302654A (en) * 1979-06-11 1981-11-24 Bennett William T Microperforation of cigarette tipping paper by use of laser beam
US5069735A (en) * 1990-06-04 1991-12-03 Milliken Research Corporation Apparatus for producing sealed edge knit wiping cloths
DE4301575A1 (en) * 1992-01-24 1993-07-29 Fraunhofer Ges Forschung Laser cutting of wire and strip - over hollow rotating cylinder housing a focussing unit
US5878464A (en) * 1996-04-16 1999-03-09 White; Homer S. Apparatus and method for converting continuous tow fibers into a staple length
WO1999059766A1 (en) * 1998-05-18 1999-11-25 Lear Corporation Laser fiber chopper

Also Published As

Publication number Publication date
BE764751A (fr) 1971-08-16
GB1312188A (en) 1973-04-04
FR2085142A5 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1971-12-17
NL7007649A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1971-09-28
DE2114483B2 (de) 1979-03-01
DE2114483A1 (de) 1971-11-11

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