CA1115136A - Method of making perforated tubular member for perforating thermoplastic film - Google Patents
Method of making perforated tubular member for perforating thermoplastic filmInfo
- Publication number
- CA1115136A CA1115136A CA367,832A CA367832A CA1115136A CA 1115136 A CA1115136 A CA 1115136A CA 367832 A CA367832 A CA 367832A CA 1115136 A CA1115136 A CA 1115136A
- Authority
- CA
- Canada
- Prior art keywords
- tubular member
- protruberances
- cylinder
- radially outwardly
- perforated
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Landscapes
- Shaping Of Tube Ends By Bending Or Straightening (AREA)
Abstract
METHOD OF MAKING PERFORATED TUBULAR MEMBER
FOR PERFORATING THERMOPLASTIC FILM
Abstract A method is described for making a relatively thin wall perforated tubular member having a wall which is perforated by an array of radially inwardly tapered apertures. A pattern cylinder is formed with radially outwardly extending protruberances, these being tapered to radially outwardly disposed free ends and comprising an inside-out negative pattern for the desired array of perforations. Metal is then applied between the protruberances to form an inside-out perforated tubular member, which is longitudinally slitted, reverse rolled and longitudinally seamed along the slitted edges.
FOR PERFORATING THERMOPLASTIC FILM
Abstract A method is described for making a relatively thin wall perforated tubular member having a wall which is perforated by an array of radially inwardly tapered apertures. A pattern cylinder is formed with radially outwardly extending protruberances, these being tapered to radially outwardly disposed free ends and comprising an inside-out negative pattern for the desired array of perforations. Metal is then applied between the protruberances to form an inside-out perforated tubular member, which is longitudinally slitted, reverse rolled and longitudinally seamed along the slitted edges.
Description
: `
BACKGROUND OF THE INVENTION
The present invention relates to a method of making a perforated tubular member for perforating thermoplastic film and is a divisional of Canadian application Serial No. 288,940 filed October 19, 1977.
Apparatuses comprising varlous means for unwinding, forwarding, debossing or embossing, and/or perforating, and rewinding of a ribbon or web of thermoplastic film are disclosed in the prior art: see for instance, U.S. Patent Re. 23,910 issued December 14, 1954 to L. H. Smith et al;
U.S. Patent No. 3,054,148 issued September 18, 1962 to W. F. Zimmerli; and U.S. Patent No. 2,567,275 issued September 11, 1951 to R. Colombo. See also the German Offenlegungsschrift 2,409,496 which teaches the use of radially inwardly impinging hot air jets in combination with vacuum inside a cylinder having a perforated sur-face to cause a thermoplastic sheet passing therebetween to become perforated. Also, reference U.S. Patent No.
3,674,221 issued July 4, 1972 to Coenraad E. Riemersma.
The prior art also discloses various methods of making perforated members: see for instance U.S. Patent No.
3,453,712 issued July 8, 1969 to R. G. MacKendrick; U.S.
Patent No. 3,613,208 issued October 19, 1971 to H. A.
Seberg et al.; and U.S. Patent No. 3,247,579 issued April 26, 1966 to L. H. Cattermole et al.
: The prior art does not disclose, however, solutions to all of the problems associated with providing a method of and apparatus for uniformly embossing and perforating a web of thermoplastic material, or a method of making a suitable perforated tubular member for use in such an apparatus in the manner of or degree of the present invention.
. .
. The method of Serial No. 288,940 to continuously . deboss and perforate a running ribbon of smooth thermo-plastic film comprises the steps of: establishing and maintaining control of the running film by establishing and maintaining constant tension therein; isolating a portion of the film from the constant tension while it is in contacting relation with a perforated pattern surface;
heating the tension isolated portion of the film to raise its temperature to above its thermoplastic temperature;
: 10 applying a sufficiently great pneumatic differential pressure to the heated, tension isolated portion of the film to cause the film to be debossed and perforated in the image of the perforated pattern surface; and, cooling the debossed and perforated film to lower its temperature to below the thermoplastic temperature of the film before subjecting the film to downstream tension.
The apparatus embodiment of Serial No. 288,940 com-prises a debossing-perforating cylinder having a perforated tubular-shape wall having a radially outwardly facing surface. The apparatus further comprises a frame, means for rotating the cylinder at a controlled rate on its : axis of gyration, means for smoothing and forwarding the running ribbon of film under predetermined tension onto the radially outwardly facing surface of the tubular wall at a first fixed position with respect to the frame, means for leading debossed and perforated film from the cylinder : at a second fixed position with respect to the frame which is circumferentially spaced from the first fixed position, means intermediate the first and second fixed positions 30 for applying a sufficiently high level of vacuum to the film and for heating the film to a sufficiently high . .
,; .
:
temperature to deboss and perforate the film, means for cooling the film to a temperature below its thermoplastic temperature while maintaining virtually zero tension there-in, and means for thence forwarding the film from the perforating cylinder under a predetermined level of tension.
SUMMARY OF THE INVENTION
The present invention relates to a method of making a relatively thin wall perforated tubular member having a wall which is perforated by an array of radially inwardly tapered apertures. It comprises the steps of forming a pattern cylinder having a radially outwardly facing pattern surface comprising a multiplicity of radially outwardly extending protruberances. The protruberances are tapered - to radially outwardly disposed free ends and have a rad-ially extending height at least as great as the thickness of the desired perforated wall. The protruberances are so spaced and shaped that they comprise an inside-out negative pattern for the desired array of apertures in the desired perforated wall, and so that the composite of the spaces intermediate the protruberances comprises an inside-out negative pattern for the perforated tubular member. The pattern surface is then covered with sufficient metal to ; fill the spaces intermediate the protruberances to a depth at least as great as the desired thickness of the wall of the perforated tubular member. The metal covering is then converted into an inside-out tubular member by machining the radially outwardly facing area of the metal covering sufficiently to provide a uniform thickness thereof which is substantially equal to the desired thickness of the desired perforated wall, and by then disassociating the metal covering from the pattern cylinder. The inside-out perforatéd tubular member is then converted into the desired perforated tubular member by longitudinally slitting it, reverse rolling it into the desired tubular shape, and longitudinally seaming the slitting-formed-edges together in abutting relation. The apparatus may further comprise constant tension unwind means, constant tension winding means, and means for independently maintaining different levels of vacuum sub-jacent a plurality of circumferentially disposed sectorsof the perforated tubular member as the perforating cylinder rotates. Moreover, the perforated tubular member may be teflon coated to provide better film release characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particu-larly pointing out and distinctly claiming the sub]ect matter regarded as the present invention, it is believed the invention will be better understood from the following description taken in connection with the accompanying drawings in which:
Figure 1 is a perspective schematic view of an apparaus embodying the present invention.
Figures 2 and 3 are perspective fragmentary views of the bottom side (machine side) and the top side respect-ively of a debossed and perforated thermoplastic film.
Figure 4 is a fragmentary, enlarged scale, side ; elevational view of the debossing and perforating cylinder portion of the apparatus shown in Figure 1.
Figure 5 is an enlarged scale, longitudinal sectional view of the debossing-perforating cylinder of the apparatus shown in Figure 1.
Figure 6 is an end view of the debossing-perforating cylinder shown in Figure 5.
Figure 7-is a greatly enlarged scale, fragmentary portion of the end view of the debossing-perforating cylinder shown in Figure 5.
Figure 8 is a perspective view of the perforated tubular member of the debossing-perforating cylinder shown in Figures 5 through 7 inclusive.
Figure 9 is an enlarged scale, fragmentary view of the radially outwardly facing surface of the perforated tubular member shown in Figure 8.
Figure 10 is an enlarged scale, fragmentary sectional view taken along line 10-10 of Figure 9.
Figure ll is a longitudinal sectional view of a pattern cylinder used for making the perforated tubular member shown in Figure 8.
Figure 12 is an enlarged scale, fragmentary view of the , .
-pattern cylinder shown in Figure 11 after a multiplicity of radially outwardly extending conical protruberances have been formed on its radially outwardly facing surface.
~`Figure 13 is a view of the fragment of the pattern `cylinder shown in Figure 12 after its radially outwardly facing surface has been electroplated to a sufficient thickness to cover the protruberances thereon and to fill the spaces intermediate the protruberances.
Figure 14 is a view of the fragmentary portion of the plated pattern cylinder shown in Figure 13 after sufficient plating has been removed to truncate the conical protruber--30 ances and to provide a cylindrical surface which is concen-tric with the axis of gyration of the pattern cylinder.
Figure 15 is a fragmentary view of an inside-out perforated tubular member which is in fact the plating portion of the plated pattern cylinder shown in Figure 14 after the pattern cylinder per se has been disassociated therefrom as by chemical etching.
Figure 16 is a perspective view of the inside-out perforated tubular member resulting from the sequence of operations shown in Figures 11 through 15 inclusive.
Figures 17 through 20 are perspective views which lQ sequentially show longitudinally slitting, reverse rolling, and reseaming the inside-out tubular member shown in Figure 16 to convert it into the perforated tubular member shown in Figure 8.
Figure 21 is a fragmentary sectional view taken along line 21-21 of Figure 8.
Figure 22 is a view of the fragmentary portion of the pattern cylinder shown in Figure 12 after its conical protruberances have been uniformly truncated.
Figure 23 is a view of the fragmentary portion of the pattern cylinder shown in Figure 22 after the spaces intermediate the truncated conical protruberances have been filled with a metal as by electroplating.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention, apparatus 40, is shown in Figure 1 to include constant tension film supply means 41, debossing and perforating means 43, and constant tension film forwarding and winding means 45. The frame, bearings, supports and the like which must necessarily be provided with respect to the functional members of apparatus 40 are not shown in the figures or described in detail in order to simplify and more clearly depict and disclose the present invention, it being understood that such details would be obvious to persons of ordinary skill in the art of designing thermoplastic film converting machinery.
Briefly, apparatus 40, Figure 1, comprises means for continuously converting a ribbon of thermoplastic film 50 into a debossed and perforated film 51 by directing hot air jets against one surface of the film while applying vacuum adjacent the opposite surface of the film, and while maintaining sufficeint control of the film 50 to substantially obviate wrinkling and/or macroscopically distending the film. Thus, as will be more fully des-cribed hereinafter, apparatus 40 comprises means for maintaining constant machine direction tension in the film both upstream ànd downstream of a zone where the tempera-ture of the film is greater than the thermoplastic tempera-ture of the film but in which zone there is substantially zero machine-direction and transverse-machine-direction tension tending to macroscopically distend the film. The tension is required to control and smooth a running ribbon ;` of thermoplastic film; the zero tension zone results from the film in the zone being at a sufficiently high tempera-ture to enable debossing and perforating it through the use of heat and vacuum. Figure 1 also shows greatly enlarged scale perforations in film 51 to enable visually perceiving the nature of the difference between the imperforate film 50 and the debossed and perforated film 51 as more fully described hereinafter.
Figures 2 and 3 are perspective views of fragmentary portions of debossed and perforated film 51 of a thermo-plastic material such as polyethylene which has been converted from a plain film through the use of apparatus 40, Figure 1. Such a debossed and perforated film may be used, for example, as a topsheet in an absorptive structure having tapered capillaries 53. Such structures, including disposable diapers, incontinent pads, bandages, and the like, are disclosed in U.S. Patent No. 3,929,135 which was issued December 30, 1975 to lIugh Ansley Thompson.
Figure 4 is an enlarged scale end view of the debossing and perforating means 43, Figure 1, which includes a rotat-ably mounted debossing-perforating cylinder 55, a nonrotat-ing triplex vacuum manifold assembly 56 including seals 57, and hot air jet means; heaters 59. The triplex vacuum manifold assembly 56 comprises three manifolds designated 61, 62, and 63. Figure 4 also shows a freely rotatably ; mounted lead-on idler roll 65, a power rotated lead-off/
chill roll 66, and a soft-face (e.g., low density neoprene) roll 67 which is gear driven by the chill roll through gears 68, 69, Figure 1. Briefly, by providing means (not shown) for independently controlling the degree of vacuum in the three vacuum manifolds, a thermoplastic ribbon of film running circumferentially about a portion of the debossing-perforating cylinder 55 is sequentially subjected to a first level of vacuum in a first sector ST, Figure 4, a second level of vacuum in a second sector SP, and a third level of vacuum in a third sector SC. As will be described more fully hereinafter, the vacuum applied to the film in sector ST enables maintaining upstream tension in the film, vacuum in sector SP enables perforating the film when hot air is directed radially inwardly against the film, and vacuum in sector SC enables cooling the film to below its thermoplastic temperature and enables establishing down-stream tension therein. The nip 70 intermediate chill roll 66 and the soft-face roll 67 is only nominally loaded because high pressure would iron-out the debossments which are alternatively designated tapered capillaries 53, Figures 2 and 3. However, even nominal pressure in nip 70 helps the vacuum in sector SC to isolate downstream tension (e.g.: roll winding tension) from the debossing-perforating sector SP of the debossing-perforating cylinder 55, and enables the nip 70 to peel the debossed and perforated film from the debossing-perforating cylinder 55. Moreover, while vacuum drawn ambient air passing through the film in sector SC will normally cool the film to below its thermoplastic tempera-ture, the passage of coolant through the chill roll as indicated by arrows 73, 74 in Figure 1 will enable the apparatus to handle, for instance, thicker films, or be operated, for instance, at higher speeds.
Referring back to Figure , the constant tension film supply means 41 and the constant tension film forwarding and winding means 45 are substantially identical to and function substantially identically to the corresponding portions of the apparatus shown and described in U.S.
Patent No. 3,674,221.
Briefly, however, the constant tension film supply means 41 comprises means 75 for rotatably mounting a roll 76 of thermoplastic film, a first idler roll 78, a dancer assembly 79 having a swingably mounted, freely rotatable dancer roll 80, a second idler roll 78A, a Mount Hope Vari-Bow (Registered Trademark of Mount Hope Machinery Company, Taunton, Massachusetts 02780) smoothing roll 81, the film-lead-on idler roll 65, and feedback film tension control means 83 comprising a dancer elevation position sensor 84, .
an unwind tension controller 85, and a variable-torque unwind brake 86. When the film 50 is looped from the roll 76 to the debossing-perforating cylinder 55 as shown in Figure l, the film 50 is adhered to the first sector ST, Figure 4, of the debossing-perforating cylinder 55 by vacuum applied through manifold 61. Thus, the film 50 is pulled as the debossing-perforating cylinder rotates clockwise as indicated, while the tension control loop causes the unwind brake 86 to sufficiently resist unwind-ing the roll 76 of film 50 to establish and maintain aconstant predetermined level of tension in the film in the machine direction. This, in turn, enables the film 50 to be tensioned transversely as it is drawn over the Mount Hope Vari-Bow roll 81 whereby it is smoothed; i.e., made wrinkle free by having a transverse tension developed in the film as it runs over the arcuate-shape roll 81.
The tension in the film is reduced to zero, and the film is debossed and perforated as it passes over the second sector SP, Flgure 4, of the rotating debossing-perforating cylinder 55. Then, the film is adhered to thethird sector SC of the debossing-perforating cylinder 55 by vacuum applied to manifold 63 to enable the constant tension film forwarding and winding means 45 to again establish and maintain sufficient uniform tension in the film 51 to forward the film downstream under sufficient control to, for instance, wind the film to form a roll 90 of debossed and perforated film. In this event, the torque of the winding drive motor 91 is controlled by the dancer-roll-position-responsive sensor 92 connected via trapeze 93 to dancer roll 94 through the winding drive and tension controller 95 to establish and maintain a substantially , \
~: constant predetermined level of machine direction tension in film 51. To summarize, the first and third vacuum sectors, ST and SC respectively of the debossing-perforat-ing cylinder 55 enable maintaining substantially constant upstream and downstream tension respectively in a running ribbon of film while the intermediate portion oE the film adjacent the second vacuum sector SP of the debossing-perforating cylinder 55 is subjected to tension vitiating heat and vacuum to effect debossing and perforating the film.
- Weights 96, Figure 1, on the dancer trapeze arms, 97 and 98, enable independently adjusting the upstream and : downstream levels of tension: higher tensions by placing the weights 96 further from the dancer shafts 99,100; and lower tensions by moving the weights 96 toward~ the dancer - shafts 99,100.
Referring again to Figure 1, the debossing and perfor-ating means 43 comprises the rotatably mounted debossing-perforating cylinder 55, means 110 for rotating the cylinder 55 at a controlled peripheral velocity, thenon-rotating triplex vacuum manifold assembly 56 inside the debossing-perforating cylinder 55, means not shown for applying controlled levels of vacuum inside the three . vacuum manifolds 61, 62 and 63 comprising the triplex :. manifold assembly 56, and a plurality of air heaters 59.
The debossing perforating cylinder 55, Figures 5 and 6, comprises a cage 120, a support ring 121 and a thin wall perforated tubular member 122. The cage 120 comprises a multiplicity of circumferentially spaced longitudinally extending bars 123 which are tapered to relatively small, : radially outwardly facing lands 124, and the spaced bars 123 have vacuum communicating passageways 125 provided therebetween. The bars 123 also have radially inwardly facing lands 128 which corporately provide a cylindrical vacuum sealing surface against which the vacuum seals 57, Figure 4, are biased. Thus, as the debossing-perforating cylinder 55 rotates, Figure 4, its vacuum sealing surface slides over the seals 57 of the non-rotating triplex vacuum manifold assembly 56.
The end 130, Figure 5~ of the debossing-perforating cylinder 55 disposed remotely from its driven end is open in order to provide easy insertion/removal of the triplex vacuum manifold assembly 56. Therefore, in order to rotatably support the open end 130 of the cylinder 55, it is provided with a bearing-race support ring 121, Figure 5, which rides;on bearings, not shown, which are approp-riately secured to the apparatus frame, not shown.
Figure 7 shows the perforated tubular member 122 to comprise a thin wall 140 in contacting relation with the small lands 124 of the cage 120. The lands 124 are small -20 and the tubular member 122 is thin-walled because the preferred embodiment apparatus 40, Figure 1, is configured to deboss and perforate a relatively thin thermoplastic film such as low density polyethylene film to provide small tapered capillaries, Figures 2 and 3.
Figure 8 is a perspective view of the perforated tubular member 122 of the debossing-perforating cylinder 55 having a diameter D and length L. In the preferred embodiment apparatus, D is 8.914 inches (22.64 centimeters) and L is 21.50 inches (54.61 centimeters). Also, the member has a longitudinally extending seam, 176.
` Figure 9 is a radially inwardly facing, enlarged scale view of a fragmentary portion of the perforated tubular member 122, Figure 8,- and Figure 10 is a further enlarged scale sectional view taken along line 10-10 of Figure 9.
Thus, the perforated tubular member 122 of the preferred embodiment apparatus 40 comprises a thin wall 140 having a thickness T (from about .013 inches to about .014 inches), ` and having a closely packed array of tapered holes 141 therethrough. The holes 141, Figure 9, are circumferent-ially spaced (CS) .040 inches (0.102 centimeters) center-to-center, transversely spaced (TS) .0346 inches (0.088 centimeters) center-to-center, have base diameters (BD) of .040 inches (0.102 centimeters), and hole diameters (HD) of .013-.014 inches (0.0330 to 0.0356 centimeters). The holes 141, Figùre 10, have included angles A of 90 degrees, and included half angles B of 45 degrees. Thus, the perforated tubular member 122 of the preferred embodiment apparatus 40 has approximately four-hundred-thirty-five-thousand (435,000) holes 141 in it.
Heaters 59 of the preferred apparatus, Figures 1 and 4, are Model No. 33-HS which are available from Kamweld Products Company, Inc., 90 Access Road, P.O. Box 91, Norwood, Mass. 02062. When operated on 120 volts, they provide 900 watts of heat and cause a flow of 6-8 cfm to be heated approximately 243 degrees centigrade; substan-tially higher than the thermoplastic temperature of low ; density polyethylene.
METHOD OF DEBOSSING AND PERFORATING
A_RUNNING RIBBON OF THERMOPLASTIC FILM
In view of the foregoing description of the preferred apparatus embodiment of the present invention, the method ` need not be described exhaustively. Suffice it to say, - the method of the present invention to continuously deboss and perforate a running ribbon of smooth thermoplastic film comprises the steps of: establishing and maintaining control of the running film by establishing and maintaining constant tension therein; isolating a portion of the film from the constant tension while it is in contacting rela-tion with a perforated pattern surface; heating the tension isolated portion of the film to raise its temperature to above its thermoplastic temperature; applying a suffic~
iently great pneumatic differential pressure to the heated, tension isolated portion of the film to cause the film to be debossed and perforated in the image of the perforated pattern surface; and, cooling the debossed and perforated film to lower its temperature to below the thermoplastic temperature of the film before subjecting the film to downstream tension.
METHOD OF MAKING PERFORATED TUBULAR MEMBER
The method of the present invention of making the preferred embodiment perforated tubular member 122, Figure 8, is depicted sequentially in Figures 11 through 20.
Figure 11 is a longitudinal sectional view of a pattern cylinder 150 comprising a shell 151 and two end bells 152, 153, which end bells enable the pattern cylinder 150 to be rotated on its axis. With respect to the preferred method of the present invention, shell 151 comprises 6061-T6 aluminum which is readily embossible, and which can be etched away by a fifteen percent solution of hydrochloric acid (HCl) or caustic soda (NaOH).
Figure 12 is a fragmentary sectional view of the pat-tern cylinder 150 showing an array of radially outwardly s-~
extending conical protruberances 155 on the radially out-wardly facing portion or surface 156 of the shell 151.
Such protruberances 155 can be machined but in the preferred method they are formed by metal displacement as by knurling. That is, by a metal displacing operation rather than a metal removal operation.
- Figure 13 is a fragmentary view showing a covering 158 over the protruberances 155 which covering 158 is preferably eleetrodeposited nickel; for instance, GAR Pure Electroformed Nickel which has been deposited from GAR
Proprietary Sulfamate Eleetrolyte which is available from the GAR Electroforming Division of the Mite Corporation, Danbury, Conneeticut 06810.
Figure 14 shows a fragmentary sectional portion of the electroplated pattern cylinder 150 after it has been surface ground to a sufficiently small diameter to truncate the protruberances 155 to form circular lands 160 thereon having the same diameter DL as the holes 141 through the perforated tubular member 122 being made.
2Q The shell 151 is then sufficiently etched away to release the remaining eleetroplating 158R, Figure 15, whieh is in faet an inside-out perforated tubular member 122 and is designated 122A. This is aeeomplished for instance by a solution eomprising fifteen percent hydrochloric acid or caustic soda (NaOH) as stated hereinbefore.
Figure 16 is a perspective view of an inside-out perforated tubular member 122A which has been made by the method illustrated in Figures 11 through 15, and as described above. The inside-out perforated tubular member 122A is then turned right-side-out by the method depicted ~$3~
sequentially in Figures 17 through 20, to wit: the inside-out member 122A is slit longitudinally, Figure 17, along line 170 to provide slitting forrned edges 171, 172 and then, through the use of a cylindrical forming mandrel 175, is rerolled about the mandrel 175 to the desired tubular shape. The perforated tubular member 122 is then completed by joining the slitting-formed edges 171, 172 together to form a seam 176. Preferably, the seam 176 is formed by electron beam butt welding the slitting-formed edges 171, 172 together.
Thus, when the perforated tubular member 122 is removed from the mandrel 175, Figure 20, it is the member 122 as shown in Figure 8.
Figure 21 is a fragmentary sectional view of the per-forated tubular member 122, Figure 8, and shows the right-side-out finished member 122 as compared to the inside-out tubular member 122A, Figure 15.
ALTERNATE METHOD OF MAKING
PERFORATED TUBULAR MEMBER
Figures 22 and 23 show different steps of an alternate method of making the perforated tubular member 122, Figure 8, which method utilizes several of the same steps of the preferred method described hereinabove. In the alternate method, a pattern cylinder 150 is still prepared as shown in Figure 11, and is provided with radially outwardly extending protruberances 155, Figure 12. Next, however, rather than overplate as shown in Figure 13, the protruber-ances 155 are uniformly truncated, Figure 22, as by grind-ing while rotating the pattern cylinder 150 about its axis.
The pattern cylinder 150 is then provided with a ! 30 coating 258, Figure 23, as by electroplating with Nickel after coating the truncation-formed lands 160 of the protruberances 155 with a plating resist material. Then, the surface of the plating/cylinder is ground to level the plating to provide the configuration shown in Figure 14.
The perforated tubular member is completed by releasing the plating from the pattern cylinder 150, to provide the inside-out member 122A, Figures 15 and 16, and by turning it right-side-out, as shown in Figures 17 through 20.
APPARATUS OPERATION
10To operate apparatus 40, the film 50 is looped, as shown in Figure 1, from roll 76, over idler roll 78, under dancer roll 80, over idler roll 78A, over the Mount Hope Vari-Bow roll 81, under the lead-on idler roll 65, clock-wise about the debossing-perforating cylinder 55, under the lead-off/chill roll 66, through the nip 70 intermed-iate the lead-off/chill roll 66 and the soft-face roll 67, over idler roll 78B, under dancer roll 94, over idler rol]
78C, and thence onto a spool 200 on the roll winding shaft ` 201. The idler roll 78D is mounted so that it is gravit-ationally loaded against the top portion of the roll 90 being wound. The unwind tension control loop and the winding tension control loop are activated. The drive motor 202 is then operated by the drive controller 203 in response to operator inputs and in response to the feed-back tachometer 204 to rotate the debossing-perforating cylinder 55 at a predetermined peripheral speed, and the chill roll 66 at a slightly higher (slack obviating) peripheral speed. The tension control loops respond to establish and maintain their respective predetermined levels of tension (as determined by the positions of weights 96) substantially irrespective of the film ` velocity.
~3 ~
Air is then directed through heaters 59, Figure l, and electrical power is applied thereto whereby jets of hot air issue from the heaters 59 to form a virtual curtain of hot air directed radially inwardly towards sector SP, Figure 4, of the debossing-perforating cylinder 55. With sufficient levels of vacuum applied to sectors ST and SC
to isolate sector SP from upstream and downstream tension, vacuum applied to sector SP acts in concert with the hot - air jets to deboss and perforate the film.
When the preferred apparatus is used to deboss and perforate low density polyethylene having a thickness of .001 inches at 50 feet per minute, the upstream tension is adjusted to about 8 ounces per lineal inch, the downstream tension is adjusted to about 2 ounces per lineal inch, and the levels of vacuum applied to sectors ST, SP, and SC are 5, 15, and 5 inches of mercury respectively.
; While the preferred embodiment apparatus has been shown and described as comprising unwinding and winding means, and while the preferred method of making a perfor-ated tubular member has been described as comprising the steps of electroplating nickel over aluminum and etching - release, these limitations are not believed to be critical to t~e present invention. Indeed, while these and other aspects of the present invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made with-out departing from the spirit and scope of the present invention, and it is intended to cover in the appended claims all such changes that are within the scope of the invention.
. ~
BACKGROUND OF THE INVENTION
The present invention relates to a method of making a perforated tubular member for perforating thermoplastic film and is a divisional of Canadian application Serial No. 288,940 filed October 19, 1977.
Apparatuses comprising varlous means for unwinding, forwarding, debossing or embossing, and/or perforating, and rewinding of a ribbon or web of thermoplastic film are disclosed in the prior art: see for instance, U.S. Patent Re. 23,910 issued December 14, 1954 to L. H. Smith et al;
U.S. Patent No. 3,054,148 issued September 18, 1962 to W. F. Zimmerli; and U.S. Patent No. 2,567,275 issued September 11, 1951 to R. Colombo. See also the German Offenlegungsschrift 2,409,496 which teaches the use of radially inwardly impinging hot air jets in combination with vacuum inside a cylinder having a perforated sur-face to cause a thermoplastic sheet passing therebetween to become perforated. Also, reference U.S. Patent No.
3,674,221 issued July 4, 1972 to Coenraad E. Riemersma.
The prior art also discloses various methods of making perforated members: see for instance U.S. Patent No.
3,453,712 issued July 8, 1969 to R. G. MacKendrick; U.S.
Patent No. 3,613,208 issued October 19, 1971 to H. A.
Seberg et al.; and U.S. Patent No. 3,247,579 issued April 26, 1966 to L. H. Cattermole et al.
: The prior art does not disclose, however, solutions to all of the problems associated with providing a method of and apparatus for uniformly embossing and perforating a web of thermoplastic material, or a method of making a suitable perforated tubular member for use in such an apparatus in the manner of or degree of the present invention.
. .
. The method of Serial No. 288,940 to continuously . deboss and perforate a running ribbon of smooth thermo-plastic film comprises the steps of: establishing and maintaining control of the running film by establishing and maintaining constant tension therein; isolating a portion of the film from the constant tension while it is in contacting relation with a perforated pattern surface;
heating the tension isolated portion of the film to raise its temperature to above its thermoplastic temperature;
: 10 applying a sufficiently great pneumatic differential pressure to the heated, tension isolated portion of the film to cause the film to be debossed and perforated in the image of the perforated pattern surface; and, cooling the debossed and perforated film to lower its temperature to below the thermoplastic temperature of the film before subjecting the film to downstream tension.
The apparatus embodiment of Serial No. 288,940 com-prises a debossing-perforating cylinder having a perforated tubular-shape wall having a radially outwardly facing surface. The apparatus further comprises a frame, means for rotating the cylinder at a controlled rate on its : axis of gyration, means for smoothing and forwarding the running ribbon of film under predetermined tension onto the radially outwardly facing surface of the tubular wall at a first fixed position with respect to the frame, means for leading debossed and perforated film from the cylinder : at a second fixed position with respect to the frame which is circumferentially spaced from the first fixed position, means intermediate the first and second fixed positions 30 for applying a sufficiently high level of vacuum to the film and for heating the film to a sufficiently high . .
,; .
:
temperature to deboss and perforate the film, means for cooling the film to a temperature below its thermoplastic temperature while maintaining virtually zero tension there-in, and means for thence forwarding the film from the perforating cylinder under a predetermined level of tension.
SUMMARY OF THE INVENTION
The present invention relates to a method of making a relatively thin wall perforated tubular member having a wall which is perforated by an array of radially inwardly tapered apertures. It comprises the steps of forming a pattern cylinder having a radially outwardly facing pattern surface comprising a multiplicity of radially outwardly extending protruberances. The protruberances are tapered - to radially outwardly disposed free ends and have a rad-ially extending height at least as great as the thickness of the desired perforated wall. The protruberances are so spaced and shaped that they comprise an inside-out negative pattern for the desired array of apertures in the desired perforated wall, and so that the composite of the spaces intermediate the protruberances comprises an inside-out negative pattern for the perforated tubular member. The pattern surface is then covered with sufficient metal to ; fill the spaces intermediate the protruberances to a depth at least as great as the desired thickness of the wall of the perforated tubular member. The metal covering is then converted into an inside-out tubular member by machining the radially outwardly facing area of the metal covering sufficiently to provide a uniform thickness thereof which is substantially equal to the desired thickness of the desired perforated wall, and by then disassociating the metal covering from the pattern cylinder. The inside-out perforatéd tubular member is then converted into the desired perforated tubular member by longitudinally slitting it, reverse rolling it into the desired tubular shape, and longitudinally seaming the slitting-formed-edges together in abutting relation. The apparatus may further comprise constant tension unwind means, constant tension winding means, and means for independently maintaining different levels of vacuum sub-jacent a plurality of circumferentially disposed sectorsof the perforated tubular member as the perforating cylinder rotates. Moreover, the perforated tubular member may be teflon coated to provide better film release characteristics.
BRIEF DESCRIPTION OF THE DRAWINGS
While the specification concludes with claims particu-larly pointing out and distinctly claiming the sub]ect matter regarded as the present invention, it is believed the invention will be better understood from the following description taken in connection with the accompanying drawings in which:
Figure 1 is a perspective schematic view of an apparaus embodying the present invention.
Figures 2 and 3 are perspective fragmentary views of the bottom side (machine side) and the top side respect-ively of a debossed and perforated thermoplastic film.
Figure 4 is a fragmentary, enlarged scale, side ; elevational view of the debossing and perforating cylinder portion of the apparatus shown in Figure 1.
Figure 5 is an enlarged scale, longitudinal sectional view of the debossing-perforating cylinder of the apparatus shown in Figure 1.
Figure 6 is an end view of the debossing-perforating cylinder shown in Figure 5.
Figure 7-is a greatly enlarged scale, fragmentary portion of the end view of the debossing-perforating cylinder shown in Figure 5.
Figure 8 is a perspective view of the perforated tubular member of the debossing-perforating cylinder shown in Figures 5 through 7 inclusive.
Figure 9 is an enlarged scale, fragmentary view of the radially outwardly facing surface of the perforated tubular member shown in Figure 8.
Figure 10 is an enlarged scale, fragmentary sectional view taken along line 10-10 of Figure 9.
Figure ll is a longitudinal sectional view of a pattern cylinder used for making the perforated tubular member shown in Figure 8.
Figure 12 is an enlarged scale, fragmentary view of the , .
-pattern cylinder shown in Figure 11 after a multiplicity of radially outwardly extending conical protruberances have been formed on its radially outwardly facing surface.
~`Figure 13 is a view of the fragment of the pattern `cylinder shown in Figure 12 after its radially outwardly facing surface has been electroplated to a sufficient thickness to cover the protruberances thereon and to fill the spaces intermediate the protruberances.
Figure 14 is a view of the fragmentary portion of the plated pattern cylinder shown in Figure 13 after sufficient plating has been removed to truncate the conical protruber--30 ances and to provide a cylindrical surface which is concen-tric with the axis of gyration of the pattern cylinder.
Figure 15 is a fragmentary view of an inside-out perforated tubular member which is in fact the plating portion of the plated pattern cylinder shown in Figure 14 after the pattern cylinder per se has been disassociated therefrom as by chemical etching.
Figure 16 is a perspective view of the inside-out perforated tubular member resulting from the sequence of operations shown in Figures 11 through 15 inclusive.
Figures 17 through 20 are perspective views which lQ sequentially show longitudinally slitting, reverse rolling, and reseaming the inside-out tubular member shown in Figure 16 to convert it into the perforated tubular member shown in Figure 8.
Figure 21 is a fragmentary sectional view taken along line 21-21 of Figure 8.
Figure 22 is a view of the fragmentary portion of the pattern cylinder shown in Figure 12 after its conical protruberances have been uniformly truncated.
Figure 23 is a view of the fragmentary portion of the pattern cylinder shown in Figure 22 after the spaces intermediate the truncated conical protruberances have been filled with a metal as by electroplating.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A preferred embodiment of the present invention, apparatus 40, is shown in Figure 1 to include constant tension film supply means 41, debossing and perforating means 43, and constant tension film forwarding and winding means 45. The frame, bearings, supports and the like which must necessarily be provided with respect to the functional members of apparatus 40 are not shown in the figures or described in detail in order to simplify and more clearly depict and disclose the present invention, it being understood that such details would be obvious to persons of ordinary skill in the art of designing thermoplastic film converting machinery.
Briefly, apparatus 40, Figure 1, comprises means for continuously converting a ribbon of thermoplastic film 50 into a debossed and perforated film 51 by directing hot air jets against one surface of the film while applying vacuum adjacent the opposite surface of the film, and while maintaining sufficeint control of the film 50 to substantially obviate wrinkling and/or macroscopically distending the film. Thus, as will be more fully des-cribed hereinafter, apparatus 40 comprises means for maintaining constant machine direction tension in the film both upstream ànd downstream of a zone where the tempera-ture of the film is greater than the thermoplastic tempera-ture of the film but in which zone there is substantially zero machine-direction and transverse-machine-direction tension tending to macroscopically distend the film. The tension is required to control and smooth a running ribbon ;` of thermoplastic film; the zero tension zone results from the film in the zone being at a sufficiently high tempera-ture to enable debossing and perforating it through the use of heat and vacuum. Figure 1 also shows greatly enlarged scale perforations in film 51 to enable visually perceiving the nature of the difference between the imperforate film 50 and the debossed and perforated film 51 as more fully described hereinafter.
Figures 2 and 3 are perspective views of fragmentary portions of debossed and perforated film 51 of a thermo-plastic material such as polyethylene which has been converted from a plain film through the use of apparatus 40, Figure 1. Such a debossed and perforated film may be used, for example, as a topsheet in an absorptive structure having tapered capillaries 53. Such structures, including disposable diapers, incontinent pads, bandages, and the like, are disclosed in U.S. Patent No. 3,929,135 which was issued December 30, 1975 to lIugh Ansley Thompson.
Figure 4 is an enlarged scale end view of the debossing and perforating means 43, Figure 1, which includes a rotat-ably mounted debossing-perforating cylinder 55, a nonrotat-ing triplex vacuum manifold assembly 56 including seals 57, and hot air jet means; heaters 59. The triplex vacuum manifold assembly 56 comprises three manifolds designated 61, 62, and 63. Figure 4 also shows a freely rotatably ; mounted lead-on idler roll 65, a power rotated lead-off/
chill roll 66, and a soft-face (e.g., low density neoprene) roll 67 which is gear driven by the chill roll through gears 68, 69, Figure 1. Briefly, by providing means (not shown) for independently controlling the degree of vacuum in the three vacuum manifolds, a thermoplastic ribbon of film running circumferentially about a portion of the debossing-perforating cylinder 55 is sequentially subjected to a first level of vacuum in a first sector ST, Figure 4, a second level of vacuum in a second sector SP, and a third level of vacuum in a third sector SC. As will be described more fully hereinafter, the vacuum applied to the film in sector ST enables maintaining upstream tension in the film, vacuum in sector SP enables perforating the film when hot air is directed radially inwardly against the film, and vacuum in sector SC enables cooling the film to below its thermoplastic temperature and enables establishing down-stream tension therein. The nip 70 intermediate chill roll 66 and the soft-face roll 67 is only nominally loaded because high pressure would iron-out the debossments which are alternatively designated tapered capillaries 53, Figures 2 and 3. However, even nominal pressure in nip 70 helps the vacuum in sector SC to isolate downstream tension (e.g.: roll winding tension) from the debossing-perforating sector SP of the debossing-perforating cylinder 55, and enables the nip 70 to peel the debossed and perforated film from the debossing-perforating cylinder 55. Moreover, while vacuum drawn ambient air passing through the film in sector SC will normally cool the film to below its thermoplastic tempera-ture, the passage of coolant through the chill roll as indicated by arrows 73, 74 in Figure 1 will enable the apparatus to handle, for instance, thicker films, or be operated, for instance, at higher speeds.
Referring back to Figure , the constant tension film supply means 41 and the constant tension film forwarding and winding means 45 are substantially identical to and function substantially identically to the corresponding portions of the apparatus shown and described in U.S.
Patent No. 3,674,221.
Briefly, however, the constant tension film supply means 41 comprises means 75 for rotatably mounting a roll 76 of thermoplastic film, a first idler roll 78, a dancer assembly 79 having a swingably mounted, freely rotatable dancer roll 80, a second idler roll 78A, a Mount Hope Vari-Bow (Registered Trademark of Mount Hope Machinery Company, Taunton, Massachusetts 02780) smoothing roll 81, the film-lead-on idler roll 65, and feedback film tension control means 83 comprising a dancer elevation position sensor 84, .
an unwind tension controller 85, and a variable-torque unwind brake 86. When the film 50 is looped from the roll 76 to the debossing-perforating cylinder 55 as shown in Figure l, the film 50 is adhered to the first sector ST, Figure 4, of the debossing-perforating cylinder 55 by vacuum applied through manifold 61. Thus, the film 50 is pulled as the debossing-perforating cylinder rotates clockwise as indicated, while the tension control loop causes the unwind brake 86 to sufficiently resist unwind-ing the roll 76 of film 50 to establish and maintain aconstant predetermined level of tension in the film in the machine direction. This, in turn, enables the film 50 to be tensioned transversely as it is drawn over the Mount Hope Vari-Bow roll 81 whereby it is smoothed; i.e., made wrinkle free by having a transverse tension developed in the film as it runs over the arcuate-shape roll 81.
The tension in the film is reduced to zero, and the film is debossed and perforated as it passes over the second sector SP, Flgure 4, of the rotating debossing-perforating cylinder 55. Then, the film is adhered to thethird sector SC of the debossing-perforating cylinder 55 by vacuum applied to manifold 63 to enable the constant tension film forwarding and winding means 45 to again establish and maintain sufficient uniform tension in the film 51 to forward the film downstream under sufficient control to, for instance, wind the film to form a roll 90 of debossed and perforated film. In this event, the torque of the winding drive motor 91 is controlled by the dancer-roll-position-responsive sensor 92 connected via trapeze 93 to dancer roll 94 through the winding drive and tension controller 95 to establish and maintain a substantially , \
~: constant predetermined level of machine direction tension in film 51. To summarize, the first and third vacuum sectors, ST and SC respectively of the debossing-perforat-ing cylinder 55 enable maintaining substantially constant upstream and downstream tension respectively in a running ribbon of film while the intermediate portion oE the film adjacent the second vacuum sector SP of the debossing-perforating cylinder 55 is subjected to tension vitiating heat and vacuum to effect debossing and perforating the film.
- Weights 96, Figure 1, on the dancer trapeze arms, 97 and 98, enable independently adjusting the upstream and : downstream levels of tension: higher tensions by placing the weights 96 further from the dancer shafts 99,100; and lower tensions by moving the weights 96 toward~ the dancer - shafts 99,100.
Referring again to Figure 1, the debossing and perfor-ating means 43 comprises the rotatably mounted debossing-perforating cylinder 55, means 110 for rotating the cylinder 55 at a controlled peripheral velocity, thenon-rotating triplex vacuum manifold assembly 56 inside the debossing-perforating cylinder 55, means not shown for applying controlled levels of vacuum inside the three . vacuum manifolds 61, 62 and 63 comprising the triplex :. manifold assembly 56, and a plurality of air heaters 59.
The debossing perforating cylinder 55, Figures 5 and 6, comprises a cage 120, a support ring 121 and a thin wall perforated tubular member 122. The cage 120 comprises a multiplicity of circumferentially spaced longitudinally extending bars 123 which are tapered to relatively small, : radially outwardly facing lands 124, and the spaced bars 123 have vacuum communicating passageways 125 provided therebetween. The bars 123 also have radially inwardly facing lands 128 which corporately provide a cylindrical vacuum sealing surface against which the vacuum seals 57, Figure 4, are biased. Thus, as the debossing-perforating cylinder 55 rotates, Figure 4, its vacuum sealing surface slides over the seals 57 of the non-rotating triplex vacuum manifold assembly 56.
The end 130, Figure 5~ of the debossing-perforating cylinder 55 disposed remotely from its driven end is open in order to provide easy insertion/removal of the triplex vacuum manifold assembly 56. Therefore, in order to rotatably support the open end 130 of the cylinder 55, it is provided with a bearing-race support ring 121, Figure 5, which rides;on bearings, not shown, which are approp-riately secured to the apparatus frame, not shown.
Figure 7 shows the perforated tubular member 122 to comprise a thin wall 140 in contacting relation with the small lands 124 of the cage 120. The lands 124 are small -20 and the tubular member 122 is thin-walled because the preferred embodiment apparatus 40, Figure 1, is configured to deboss and perforate a relatively thin thermoplastic film such as low density polyethylene film to provide small tapered capillaries, Figures 2 and 3.
Figure 8 is a perspective view of the perforated tubular member 122 of the debossing-perforating cylinder 55 having a diameter D and length L. In the preferred embodiment apparatus, D is 8.914 inches (22.64 centimeters) and L is 21.50 inches (54.61 centimeters). Also, the member has a longitudinally extending seam, 176.
` Figure 9 is a radially inwardly facing, enlarged scale view of a fragmentary portion of the perforated tubular member 122, Figure 8,- and Figure 10 is a further enlarged scale sectional view taken along line 10-10 of Figure 9.
Thus, the perforated tubular member 122 of the preferred embodiment apparatus 40 comprises a thin wall 140 having a thickness T (from about .013 inches to about .014 inches), ` and having a closely packed array of tapered holes 141 therethrough. The holes 141, Figure 9, are circumferent-ially spaced (CS) .040 inches (0.102 centimeters) center-to-center, transversely spaced (TS) .0346 inches (0.088 centimeters) center-to-center, have base diameters (BD) of .040 inches (0.102 centimeters), and hole diameters (HD) of .013-.014 inches (0.0330 to 0.0356 centimeters). The holes 141, Figùre 10, have included angles A of 90 degrees, and included half angles B of 45 degrees. Thus, the perforated tubular member 122 of the preferred embodiment apparatus 40 has approximately four-hundred-thirty-five-thousand (435,000) holes 141 in it.
Heaters 59 of the preferred apparatus, Figures 1 and 4, are Model No. 33-HS which are available from Kamweld Products Company, Inc., 90 Access Road, P.O. Box 91, Norwood, Mass. 02062. When operated on 120 volts, they provide 900 watts of heat and cause a flow of 6-8 cfm to be heated approximately 243 degrees centigrade; substan-tially higher than the thermoplastic temperature of low ; density polyethylene.
METHOD OF DEBOSSING AND PERFORATING
A_RUNNING RIBBON OF THERMOPLASTIC FILM
In view of the foregoing description of the preferred apparatus embodiment of the present invention, the method ` need not be described exhaustively. Suffice it to say, - the method of the present invention to continuously deboss and perforate a running ribbon of smooth thermoplastic film comprises the steps of: establishing and maintaining control of the running film by establishing and maintaining constant tension therein; isolating a portion of the film from the constant tension while it is in contacting rela-tion with a perforated pattern surface; heating the tension isolated portion of the film to raise its temperature to above its thermoplastic temperature; applying a suffic~
iently great pneumatic differential pressure to the heated, tension isolated portion of the film to cause the film to be debossed and perforated in the image of the perforated pattern surface; and, cooling the debossed and perforated film to lower its temperature to below the thermoplastic temperature of the film before subjecting the film to downstream tension.
METHOD OF MAKING PERFORATED TUBULAR MEMBER
The method of the present invention of making the preferred embodiment perforated tubular member 122, Figure 8, is depicted sequentially in Figures 11 through 20.
Figure 11 is a longitudinal sectional view of a pattern cylinder 150 comprising a shell 151 and two end bells 152, 153, which end bells enable the pattern cylinder 150 to be rotated on its axis. With respect to the preferred method of the present invention, shell 151 comprises 6061-T6 aluminum which is readily embossible, and which can be etched away by a fifteen percent solution of hydrochloric acid (HCl) or caustic soda (NaOH).
Figure 12 is a fragmentary sectional view of the pat-tern cylinder 150 showing an array of radially outwardly s-~
extending conical protruberances 155 on the radially out-wardly facing portion or surface 156 of the shell 151.
Such protruberances 155 can be machined but in the preferred method they are formed by metal displacement as by knurling. That is, by a metal displacing operation rather than a metal removal operation.
- Figure 13 is a fragmentary view showing a covering 158 over the protruberances 155 which covering 158 is preferably eleetrodeposited nickel; for instance, GAR Pure Electroformed Nickel which has been deposited from GAR
Proprietary Sulfamate Eleetrolyte which is available from the GAR Electroforming Division of the Mite Corporation, Danbury, Conneeticut 06810.
Figure 14 shows a fragmentary sectional portion of the electroplated pattern cylinder 150 after it has been surface ground to a sufficiently small diameter to truncate the protruberances 155 to form circular lands 160 thereon having the same diameter DL as the holes 141 through the perforated tubular member 122 being made.
2Q The shell 151 is then sufficiently etched away to release the remaining eleetroplating 158R, Figure 15, whieh is in faet an inside-out perforated tubular member 122 and is designated 122A. This is aeeomplished for instance by a solution eomprising fifteen percent hydrochloric acid or caustic soda (NaOH) as stated hereinbefore.
Figure 16 is a perspective view of an inside-out perforated tubular member 122A which has been made by the method illustrated in Figures 11 through 15, and as described above. The inside-out perforated tubular member 122A is then turned right-side-out by the method depicted ~$3~
sequentially in Figures 17 through 20, to wit: the inside-out member 122A is slit longitudinally, Figure 17, along line 170 to provide slitting forrned edges 171, 172 and then, through the use of a cylindrical forming mandrel 175, is rerolled about the mandrel 175 to the desired tubular shape. The perforated tubular member 122 is then completed by joining the slitting-formed edges 171, 172 together to form a seam 176. Preferably, the seam 176 is formed by electron beam butt welding the slitting-formed edges 171, 172 together.
Thus, when the perforated tubular member 122 is removed from the mandrel 175, Figure 20, it is the member 122 as shown in Figure 8.
Figure 21 is a fragmentary sectional view of the per-forated tubular member 122, Figure 8, and shows the right-side-out finished member 122 as compared to the inside-out tubular member 122A, Figure 15.
ALTERNATE METHOD OF MAKING
PERFORATED TUBULAR MEMBER
Figures 22 and 23 show different steps of an alternate method of making the perforated tubular member 122, Figure 8, which method utilizes several of the same steps of the preferred method described hereinabove. In the alternate method, a pattern cylinder 150 is still prepared as shown in Figure 11, and is provided with radially outwardly extending protruberances 155, Figure 12. Next, however, rather than overplate as shown in Figure 13, the protruber-ances 155 are uniformly truncated, Figure 22, as by grind-ing while rotating the pattern cylinder 150 about its axis.
The pattern cylinder 150 is then provided with a ! 30 coating 258, Figure 23, as by electroplating with Nickel after coating the truncation-formed lands 160 of the protruberances 155 with a plating resist material. Then, the surface of the plating/cylinder is ground to level the plating to provide the configuration shown in Figure 14.
The perforated tubular member is completed by releasing the plating from the pattern cylinder 150, to provide the inside-out member 122A, Figures 15 and 16, and by turning it right-side-out, as shown in Figures 17 through 20.
APPARATUS OPERATION
10To operate apparatus 40, the film 50 is looped, as shown in Figure 1, from roll 76, over idler roll 78, under dancer roll 80, over idler roll 78A, over the Mount Hope Vari-Bow roll 81, under the lead-on idler roll 65, clock-wise about the debossing-perforating cylinder 55, under the lead-off/chill roll 66, through the nip 70 intermed-iate the lead-off/chill roll 66 and the soft-face roll 67, over idler roll 78B, under dancer roll 94, over idler rol]
78C, and thence onto a spool 200 on the roll winding shaft ` 201. The idler roll 78D is mounted so that it is gravit-ationally loaded against the top portion of the roll 90 being wound. The unwind tension control loop and the winding tension control loop are activated. The drive motor 202 is then operated by the drive controller 203 in response to operator inputs and in response to the feed-back tachometer 204 to rotate the debossing-perforating cylinder 55 at a predetermined peripheral speed, and the chill roll 66 at a slightly higher (slack obviating) peripheral speed. The tension control loops respond to establish and maintain their respective predetermined levels of tension (as determined by the positions of weights 96) substantially irrespective of the film ` velocity.
~3 ~
Air is then directed through heaters 59, Figure l, and electrical power is applied thereto whereby jets of hot air issue from the heaters 59 to form a virtual curtain of hot air directed radially inwardly towards sector SP, Figure 4, of the debossing-perforating cylinder 55. With sufficient levels of vacuum applied to sectors ST and SC
to isolate sector SP from upstream and downstream tension, vacuum applied to sector SP acts in concert with the hot - air jets to deboss and perforate the film.
When the preferred apparatus is used to deboss and perforate low density polyethylene having a thickness of .001 inches at 50 feet per minute, the upstream tension is adjusted to about 8 ounces per lineal inch, the downstream tension is adjusted to about 2 ounces per lineal inch, and the levels of vacuum applied to sectors ST, SP, and SC are 5, 15, and 5 inches of mercury respectively.
; While the preferred embodiment apparatus has been shown and described as comprising unwinding and winding means, and while the preferred method of making a perfor-ated tubular member has been described as comprising the steps of electroplating nickel over aluminum and etching - release, these limitations are not believed to be critical to t~e present invention. Indeed, while these and other aspects of the present invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications can be made with-out departing from the spirit and scope of the present invention, and it is intended to cover in the appended claims all such changes that are within the scope of the invention.
. ~
Claims (6)
1. A method of making a perforated tubular member having a relatively thin tubular wall of a metal which wall is perforated by an array of radially inwardly tapered apertures, said method comprising the steps of:
forming a pattern cylinder having a cylindrical surface and a multiplicity of protruberances extending radially outwardly from said cylindrical surface, said protruberances being tapered radially outwardly and having a radially extending height greater than the thickness of said wall, said protruberances being so spaced and shaped that they comprise an inside-out negative pattern for said array of apertures and so that the composite of the spaces intermediate said protruberances comprise an inside-out negative pattern for said member;
covering said cylindrical surface and filling said spaces with a coherent mass of said metal to provide a coating;
converting said coating into an inside-out said tubular member by machining the radially outwardly facing areas of said coating and said protruberances to truncate said protruberances to uniform heights equal to the thickness of said wall and to cause said coating to have a thickness equal to the desired thickness of said tubular wall;
disassociating said inside-out tubular member from said pattern cylinder;
converting said inside-out tubular member into said tubular wall by longitudinally slitting it, reverse rolling it into its ultimate tubular shape, and seaming the slitting-formed-edges together in abutting relation.
forming a pattern cylinder having a cylindrical surface and a multiplicity of protruberances extending radially outwardly from said cylindrical surface, said protruberances being tapered radially outwardly and having a radially extending height greater than the thickness of said wall, said protruberances being so spaced and shaped that they comprise an inside-out negative pattern for said array of apertures and so that the composite of the spaces intermediate said protruberances comprise an inside-out negative pattern for said member;
covering said cylindrical surface and filling said spaces with a coherent mass of said metal to provide a coating;
converting said coating into an inside-out said tubular member by machining the radially outwardly facing areas of said coating and said protruberances to truncate said protruberances to uniform heights equal to the thickness of said wall and to cause said coating to have a thickness equal to the desired thickness of said tubular wall;
disassociating said inside-out tubular member from said pattern cylinder;
converting said inside-out tubular member into said tubular wall by longitudinally slitting it, reverse rolling it into its ultimate tubular shape, and seaming the slitting-formed-edges together in abutting relation.
2. The method of claim 1 further comprising the step of coating the radially outwardly facing surface of said perforated tubular member with release enhancing material.
3. The method of claim 1 wherein said cylinder comprises a malleable metal, said protruberances are formed by knurl-ing the radially outwardly facing surface of said cylinder, said coating is formed by electrodepositing said metal; and said disassociating is accomplished by chemically etching said cylinder.
4. A method of making a perforated tubular member having a relatively thin tubular wall of a metal which wall is perforated by an array of radially inwardly tapered apertures, said method comprising the steps of:
forming a pattern cylinder having a cylindrical surface and a multiplicity of protruberances extending radially outwardly from said cylindrical surface, said protruber-ances being tapered radially outwardly and having a radially extending height greater than the thickness of said wall, said protruberances being so spaced and shaped that they comprise an inside-out negative pattern for said array of apertures and so that the composite of the spaces intermediate said protruberances comprise an inside-out negative pattern for said member;
uniformly truncating said protruberances to form radially outwardly facing lands thereon and to reduce their heights to the desired thickness of said wall;
covering said cylindrical surface but for said lands, and filling said spaces with a coherent mass of said metal to provide a coating;
converting said coating into an inside-out said tubular member by machining the radially outwardly facing areas of said coating to a thickness equal to the desired thickness of said tubular wall;
disassociating said inside-out tubular member from said pattern cylinder;
converting said inside-out tubular member into said tubular wall by longitudinally slitting it, reverse rolling it into its ultimate tubular shape, and seaming the slitting-formed-edges together in abutting relation.
forming a pattern cylinder having a cylindrical surface and a multiplicity of protruberances extending radially outwardly from said cylindrical surface, said protruber-ances being tapered radially outwardly and having a radially extending height greater than the thickness of said wall, said protruberances being so spaced and shaped that they comprise an inside-out negative pattern for said array of apertures and so that the composite of the spaces intermediate said protruberances comprise an inside-out negative pattern for said member;
uniformly truncating said protruberances to form radially outwardly facing lands thereon and to reduce their heights to the desired thickness of said wall;
covering said cylindrical surface but for said lands, and filling said spaces with a coherent mass of said metal to provide a coating;
converting said coating into an inside-out said tubular member by machining the radially outwardly facing areas of said coating to a thickness equal to the desired thickness of said tubular wall;
disassociating said inside-out tubular member from said pattern cylinder;
converting said inside-out tubular member into said tubular wall by longitudinally slitting it, reverse rolling it into its ultimate tubular shape, and seaming the slitting-formed-edges together in abutting relation.
5. The method of claim 4 further comprising the step of coating the radially outwardly facing surface of said perforated tubular member with release enhancing material.
6. The method of claim 4 wherein said cylinder comprises malleable metal, said protruberances are formed by knurling the radially outwardly facing surface of said cylinder, said coating is formed by electrodepositing said metal;
and said disassociating is accomplished by chemically etching said cylinder.
and said disassociating is accomplished by chemically etching said cylinder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA367,832A CA1115136A (en) | 1976-10-19 | 1980-12-31 | Method of making perforated tubular member for perforating thermoplastic film |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/733,961 US4151240A (en) | 1976-10-19 | 1976-10-19 | Method for debossing and perforating a running ribbon of thermoplastic film |
| US733,961 | 1976-10-19 | ||
| CA288,940A CA1111223A (en) | 1976-10-19 | 1977-10-18 | Method of and apparatus for debossing and perforating a running ribbon of thermoplastic film |
| CA367,832A CA1115136A (en) | 1976-10-19 | 1980-12-31 | Method of making perforated tubular member for perforating thermoplastic film |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1115136A true CA1115136A (en) | 1981-12-29 |
Family
ID=27165327
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA367,832A Expired CA1115136A (en) | 1976-10-19 | 1980-12-31 | Method of making perforated tubular member for perforating thermoplastic film |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1115136A (en) |
-
1980
- 1980-12-31 CA CA367,832A patent/CA1115136A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1111223A (en) | Method of and apparatus for debossing and perforating a running ribbon of thermoplastic film | |
| US4509908A (en) | Apparatus for uniformly debossing and aperturing a resilient plastic web | |
| US4364723A (en) | Apparatus for texturing a thermoplastic film | |
| US4441952A (en) | Method and apparatus for uniformly debossing and aperturing a resilient plastic web | |
| CA1133321A (en) | Method and apparatus for embossing and perforating a running ribbon of thermoplastic film on a metallic pattern roll | |
| US4214945A (en) | Method of making a perforated tubular member | |
| JP2502964B2 (en) | Method and apparatus for uniformly debossing and opening a moving plastic web using fixed support members in both forming areas | |
| US4741877A (en) | Uniformly debossing and aperturing a moving plastic web using stationary support member in forming area | |
| US4233017A (en) | Apparatus for debossing and perforating a running ribbon of thermoplastic film | |
| US6277224B1 (en) | Ultrasonic perforator and a method for performing an ultrasonic perforation | |
| FI77810B (en) | TREDIMENSIONAL FORMNINGSSTRUKTUR OCH KONTINUERLIGT FOERFARANDE FOER BILDANDE AV PRAEGLINGSMOENSTER PAO EN PLASTBANA OCH SAO BILDAT PLASTBANA. | |
| US3756884A (en) | W closed cells process and apparatus for producing laminanted structure having hollo | |
| EP0705785A2 (en) | Method and apparatus for preventing creases in thin webs | |
| US4747991A (en) | Method for debossing and selectively aperturing a resilient plastic web | |
| JPS60177900A (en) | High-speed manufacture of web of deboss/porous thermoplasticfilm | |
| JP2783883B2 (en) | No-mouth vacuum drum for web transport | |
| JPS62158017A (en) | Device and method of manufacturing thin tube | |
| JPS59188407A (en) | Manufacture of soft plastic film | |
| PT84836B (en) | Process and apparatus for the production of perforated films, in particular perforated bands of plastics material for sanitary products | |
| CA2105065A1 (en) | Apparatus and method for producing an elongate strip of material | |
| EP0018684B1 (en) | Disposable absorbent structure having a textured macroscopically perforated thermoplastic film topsheet | |
| CA1115136A (en) | Method of making perforated tubular member for perforating thermoplastic film | |
| JPS6363373B2 (en) | ||
| JPH01221223A (en) | Lining material for pipe line and its manufacture | |
| CA1282765C (en) | Apparatus and process for forming center unwindable rolls of perforatedplastic film |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |