OF MICROFLUIDIC DEVICES

Field of the Invention

The present invention relates to the field of microfluidic devices having microchannels, and particularly relates to a method and apparatus for continuous formation of such microfluidic devices.

Background of the Invention

Microfluidic devices, often referred to as "lab-on-a-chip" devices, have been applied to many applications, primarily in the life sciences, for testing various biochemical systems in a protected environment provided by microchannels formed in the microfluidic devices. Microfluidic devices are generally provided with one or more enclosed microchannels extending between apertures that communicate with the exterior of the microfluidic device. The apertures form inlet ports for liquid samples to be introduced to the microchannels. Microfluidic devices have traditionally been formed utilising silicon, glass or quartz substrates, utilising micromachining by way of a masking and etching process, followed by bonding an additional layer of material to the substrate so as to encapsulate the microchannels formed in the substrate surface. The substrate materials utilised are relatively expensive, particularly when high volume production is required. The processes of microchannel production are also relatively complicated and expensive.

The use of plastic substrates, which are less expensive than the other earlier used substrates has also been proposed, however the discrete manufacturing processes, which include embossing and laser micromachining, have not been particularly efficient for large production volumes.

Object of the Invention

It is the object of the present invention to overcome or at least substantially ameliorate at least one of the above disadvantages.

Summary of the Invention

There is disclosed herein a method for continuous formation of microfluidic devices comprising the steps of:

(a) advancing a first continuous web through a groove forming station; (b) at said groove forming station, forming a groove in a first face of said first continuous web;

(c) advancing said first continuous web through an aperture forming station;

(d) at said aperture forming station, forming an aperture extending through a thickness of said first continuous web at or adjacent each end of said groove; (e) advancing said first continuous web and a second continuous web through a laminating station;

(f) at said laminating station, laminating said first face of said first continuous web to a first face of said second continuous web, thereby forming a laminated web;

(g) advancing said laminated web through a cutting station; (h) at said cutting station, cutting a microfluidic device from a portion of said laminated web including said apertures and groove; and

(i) repeating steps (b), (d), (f) and (h) at successive portions of said first continuous web as said first continuous web passes through said groove forming station, said aperture forming station, said laminating station and said cutting station. The first continuous web may include an adhesive layer forming said first face of said first continuous web, said groove being formed in said adhesive layer. The first continuous web may comprise said adhesive layer and a flexible plastic film. Steps (c) and (d) may precede steps (a) and (b). Step (b) may comprise the sub-steps of: i) locating a wire adjacent said first face of said first continuous web; ii) laminating said first face of said first continuous web to a sacrificial web with said wire located therebetween, pressing said wire into said first face of said first continuous web; iii) delaminating said sacrificial web from said first face of said first continuous web; and iv) removing said wire from said first face of said first continuous web, leaving said groove formed in said first face of said first continuous web.

At step (d), said apertures may be punched through said first continuous web.

At step (d), said apertures may alternatively be cut through said first continuous web.

At step (b), said groove may be formed in said first continuous web by passing said first continuous web through a pair of opposing groove forming rollers, one of said groove forming rollers having a groove forming projection formed on a circumferential surface thereof.

At step (b), said groove may alternatively be cut into said first face of said first continuous web.

At step (f), said first face of said first continuous web may be laminated to said second continuous web by passing said first and second continuous webs between a pair of heated laminating rollers.

The second continuous web may comprise a flexible plastic film.

The first continuous web may be advanced through said groove forming station from a first continuous web supply roller. The second continuous web may be advanced through said laminating station from a second continuous web supply roller.

Subsequent to step (h) said laminated web is typically wound onto a receiving roller.

The method may further comprise prior to step (e), the step of depositing an electrode formed of a layer of conductive material on either said first face of said first continuous web or said first face of said second continuous web, said electrode being aligned with said groove. The electrode may be formed of a metallic layer.

Steps (a), (c), (e) and (g) may be carried out continuously.

Steps (a), (c), (e) and (g) may alternatively be carried out intermittently, said first continuous web being stopped to carry out steps (b), (d), (f) and (h). Steps (b), (d), (f) and (h) are typically carried out simultaneously at successive portions of said first continuous web whilst said first continuous web is stopped.

There is further disclosed herein a method for continuous formation of microfluidic devices comprising the steps of: (a) advancing a first continuous web through a groove forming station;

(b) at said groove forming station, forming a groove in a first face of said first continuous web;

(c) advancing a second continuous web through an aperture forming station;

(d) at said aperture forming station, forming two apertures extending through a thickness of said second continuous web;

(e) advancing said first continuous web and said second continuous web through a laminating station; (f) at said laminating station, laminating said first face of said first continuous web to a first face of said second continuous web with said apertures aligned with said groove at or adjacent each end of said groove;

(g) advancing said laminated web through a cutting station; (h) at said cutting station, cutting a microfluidic device from a portion of said laminated web including said apertures and groove; and

(i) repeating steps (b), (f) and (h) at successive portions of said first continuous web as said first continuous web passes through said groove forming station, said laminating station and said cutting station and repeating step (d) at successive portions of said second continuous web as said second continuous web passes through said aperture forming station.

The first continuous web may include an adhesive layer forming said first face of said first continuous web, said groove being formed in said adhesive layer. The first continuous web may comprise said adhesive layer and a flexible plastic film.

At step (d), said apertures may be punched through said second continuous web. At step (d), said apertures may alternatively be cut through said second continuous web.

At step (b), said groove may be formed in said first continuous web by passing said first continuous web through a pair of opposing groove forming rollers, one of said groove forming rollers having a groove forming projection formed on a circumferential surface thereof.

At step (b), said groove may alternatively be cut into said first face of said first continuous web.

At step (f), said first face of said first continuous web may be laminated to said second continuous web by passing said first and second continuous webs between a pair of heated laminating rollers.

The second continuous web may comprise a flexible plastic film. The first continuous web may be advanced through said groove forming station from a first continuous web supply roller.

The second continuous web may be advanced through said aperture forming station from a second continuous web supply roller.

Subsequent to step (h) said laminated web is typically wound onto a receiving roller. The method may further comprise prior to step (e), the step of depositing an electrode formed of a layer of conductive material on either said first face of said first continuous web or said first face of said second continuous web, said electrode being aligned with said groove. The electrode may be formed of a metallic layer.

Steps (a), (c), (e) and (g) may be carried out continuously. There is still further disclosed herein an apparatus for continuous formation of microfluidic devices comprising: a groove forming station for forming a groove in a first face of a first continuous web; an aperture forming station for forming an aperture through a thickness of said first continuous web; a laminating station for laminating the first face of the first continuous web to a first face of a second continuous web; and a cutting station for cutting a microfluidic device from a portion of the laminating web including the aperture and groove; and a drive for advancing the first continuous web through said groove forming station, said aperture forming station, said laminating station and said cutting station.

The groove forming station may comprise a pair of opposing groove forming rollers, one of said groove forming rollers having a groove forming projection formed on a circumferential surface thereof. The groove forming station may alternatively comprise a groove cutting device.

The laminating station may comprise a pair of opposing heated laminating rollers.

The aperture forming station may comprise a pair of aperture forming rollers, one of said aperture forming rollers having a pair of punches projecting from a circumferential surface thereof. In one embodiment, said groove forming station comprises: a wire locating sub-station for locating a wire adjacent the first face of the first continuous web;

an auxiliary laminating sub-station for laminating the first face of the first continuous web to a sacrificial web with the wire located therebetween; a delaminating sub-station for delaminating the sacrificial web from the first face of the first continuous web; a wire removal station for removing the wire from the first face of the first continuous web.

There is yet further disclosed herein an apparatus for continuous formation of microfluidic devices comprising: a groove forming station for forming a groove in a first face of a first continuous web; an aperture forming station for forming an aperture through a thickness of a second continuous web; a laminating station for laminating the first face of the first continuous web to a first face of the second continuous web; and a cutting station for cutting a microfluidic device from a portion of the laminating web including the aperture and groove; and a drive for advancing the first continuous web through said groove forming station, said laminating station and said cutting station and for advancing the second continuous web through said aperture forming station, said laminating station and said cutting station. The groove forming station may comprise a pair of opposing groove forming rollers, one of said groove forming rollers having a groove forming projection formed on a circumferential surface thereof.

The groove forming station may alternatively comprise a groove cutting device.

The laminating station may comprise a pair of opposing heated laminating rollers. The aperture forming station may comprise a pair of aperture forming rollers, one of said aperture forming rollers having a pair of punches projecting from a circumferential surface thereof.

Brief Description of the Drawings

Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:

Figure 1 is a perspective view of a first embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 2 is a perspective view of a microfluidic device formed using the method and apparatus of Figure 1.

Figure 3 is a cross-sectional view of the microfluidic device of Figure 2 taken at Section 3-3. Figure 4 is a perspective view of a second embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 5 is a perspective view of a third embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 6 is a perspective view of a fourth embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 7 is a perspective view of a fifth embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 8 is a cross-sectional view of a microfluidic device formed using the method and apparatus of Figure 7. Figure 9 is a side elevation view of a sixth embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 10 is a partial side elevation view of a seventh embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 11 is a perspective view of an eighth embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figure 12 is a perspective view of a ninth embodiment of a method and apparatus for continuous formation of microfluidic devices.

Figures 13a to 13d are each cross-sectional views depicting formation of a microfluidic device at various stages of the method and apparatus of Figure 12.

Detailed Description of the Drawings

A first embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 1. A first continuous web 1 is provided on a first continuous web supply roller 2. The first continuous web 1 may comprise a flexible plastic film, such as polyester, which may be transparent if the end use of the mircofluidic device requires visual inspection of the microchannel formed therein. Here the first continuous web 1 comprises an adhesive layer 3 forming the first face Ia of the first continuous web 1 and a polyester plastic film 4 forming the second face Ib of the first

continuous web 1. The adhesive layer 3 is here formed of a polyethylene adhesive. A typical thickness of the first continuous web 1 is approximately 100 micrometres, comprising 40 micrometres for the adhesive layer 3 and 60 micrometres for the plastic film 4. It is also envisaged that the first continuous web 1 may be formed of a thin metal 5 film, such as aluminum, or a thin metal layer mounted on a thin plastic film.

The first continuous web 1 is advanced to a groove forming station 5. The groove forming station 5 here comprises a pair of opposing groove forming rollers 6, 7. Here the groove forming rollers 6, 7 have a diameter of approximately 2 cm and length of approximately 34 cm, but various sizes may be used as suitable. The first groove forming o roller 6 has a groove forming projection 8 formed on its circumferential surface. The groove forming projection 8 extends perpendicularly to the longitudinal axis of the first groove forming roller 6. As the first continuous web 1 advances between the groove forming rollers 6, 7, the groove forming projection 8 presses into the adhesive layer 3, forming a longitudinally extending groove 9 having an arc length of approximately 460 s micrometres.

The first continuous web 1 is then advanced through an aperture forming station 10. The aperture forming station 10 here comprises a pair of opposing aperture forming rollers 11, 12. The first aperture forming roller 11 is provided with two aperture forming punches 13. The aperture forming punches 13 are spaced about the circumference of the 0 first aperture forming roller 11 a distance equal to the length of the groove 9. The first aperture forming roller 11 is in register with the first groove forming roller 6 such that, as the first continuous web 1 passes between the aperture forming rollers 11, 12, apertures 14 are punched through the thickness of the first continuous web 1 at or adjacent each opposing end of the groove 9. s A second continuous web 15 is provided on a second continuous web supply roller

16. The second continuous web 15 may be formed of a flexible plastics material, again such as polyester, or may comprise a thin metallic film if desired. Here the second continuous web is formed of a polyester film approximately 60 micrometres thick, however thicknesses up to or beyond 100 micrometres would be typical. 0 Both the first and second continuous webs 1, 15 are advanced through a laminating station 17. Here the laminating station 17 comprises a pair of heated laminated rollers 18, 19 that are heated to a temperature of approximately 100° to 110° C. As the first and second continuous webs 1, 15 pass between the laminating rollers 18, 19, the heat and

pressure from the laminating rollers 18, 19 acting on the first and second continuous webs 1, 2 activates the adhesive layer 3 of the first continuous web 1 so as to bond the first face Ia of the first continuous web 1 with the first face 15a of the second continuous web 15, thereby forming a laminated web 20. Whilst, in the first embodiment, the first and second continuous webs 1, 15 are laminated at the laminating station 17 by an adhesive bonding process, with the first continuous web 1 being provided with an adhesive layer 3, it is envisaged that other known laminating processes might be utilised, including plastic welding of two plastic film continuous webs (with the adhesive layer being omitted). It is also envisaged that other thermal energy generation means to laminate the first and second webs 1, 15, such as friction welding, welding using ultrasonic waves, laser heating or electromagnetic wave heating (including RF heating) may be utilised. It is also envisaged that plastic to metal and metal to metal laminating methods might be utilised where one or both continuous webs 1, 15 are formed of a metallic film. Continuous bonding may also be utilised for the laminated process. Where no adhesive layer 3 is utilised on either of the first and second continuous webs 1, 15 the groove 9 may be formed directly in the first face of either of the first and second continuous webs 1, 15.

The laminated web 20 is next advanced through a cutting station 21. The cutting station 21 comprises a pair of opposing cutting rollers 22, 23. The first cutting roller 22 is provided with an arrangement of cutting projections 24. As the laminated web 20 passes through the cutting rollers 22, 23, the cutting projections 24 cut a rectangular shape around the groove 9 and apertures 14 previously formed, provided a discrete microfluidic device 25. The microfluidic device 25 cut out of the laminated web 20 falls into a collection receptacle 26 or a collection hopper, chute or the like. The remaining section of the laminated web 20, having a cut out region where the microfluidic device 25 is cut from, is wound onto a receiving roller 27. The receiving roller 27 will typically be driven by a drive unit 28 which acts to draw the laminated web 20 and first and second continuous webs 1, 15 through the various above described stations. The above described process is a continuous process, with a groove 9 being formed in successive portions of the first continuous web 1 for every successive full rotation of the first and second groove forming rollers 6, 7, with apertures 14 similarly being formed in successive portions of the first continuous web 1 as the first continuous web 1 passes

through the rotating aperture forming rollers 11, 12. Microfluidic devices 25 are similarly cut from the laminated web 20 at successive portions of the laminated web 20 as it passes through the cutting rollers 22, 23.

Referring to Figures 2 and 3, a discrete microfluidic device 25 formed using the above method and apparatus of the first embodiment may have a length of the order of 6 cm and width of the order of 3 cm. The groove 9 formed in the adhesive layer 3 forms a microchannel 29 which has its opposing ends communicating with the exterior of the microfluidic device 29 via the apertures 14 formed at each opposing end of the groove 9. The microchannel 29, formed from a groove 9 with an arc length of 460 micrometres, that is partially flattened during the lamination process, has a depth of about 15 micrometres and a width of about 143 micrometres.

A second embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 4. The same reference numerals are used to depict the features of the second embodiment that are common with that of the first embodiment. The second embodiment is generally the same as the first embodiment, except that the aperture forming station 10' comprises a first laser cutting device 30 which is programmed to cut the apertures 14 in the first continuous web 1 at each opposing end of each successive groove 9. Similarly, the cutting station 21' comprises a second laser cutting device 31 programmed to cut discrete rectangular microfluidic devices 25 from the laminated web 20 as it passes through the cutting station 21'. Rather than using laser cutting devices, water cutting devices, or any other suitable cutting means, are also envisaged. Further, rather than pressing the groove 9 into the first face Ia of the first continuous web 1, the groove 9 is cut into the first face Ia of the first continuous web 1 at the groove forming station 5' by a groove cutting device 58, here in the form of a third laser cutting device. The third laser cutting device 58 is typically a low power or modulated laser configured to cut through the first continuous web 1 to the desired depth. Other cutting devices, such as water cutting devices may alternatively be utilised as desired.

A third embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 5. This method and apparatus is identical to that of the first embodiment, except that the aperture forming station 10 is located upstream of the groove forming station 5. Accordingly, the apertures 14 are formed in the first continuous web 1 at a distance apart equal to the length of the groove 9 to be

subsequently formed in the first face Ia of the first continuous web 1, with the groove forming rollers 6, 7 being maintained in register with the aperture forming rollers 11, 12 such that the groove 9 extends between the apertures 14, providing the same end result as the first embodiment.

5 A fourth embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 6. The fourth embodiment is identical to the first and third embodiments, except that the aperture and groove forming stations are combined into a single station 32 formed of a pair of opposing aperture and groove forming rollers 33, 34. The groove forming projection 8 and aperture forming punches 13

I ₀ are both formed on the first aperture and groove forming roller 33 such that the groove 9 and apertures 14 are formed in a single pass through the aperture and groove forming rollers 33, 34.

A fifth embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 7. The fifth embodiment is identical to the first is embodiment, except that the aperture forming station 10 is arranged such that the second continuous web 15 is advanced therethrough, with the apertures 14 being formed extending through the thickness of the second continuous web 15 by the punches 13 on the first aperture forming roller 11. The first and second aperture forming rollers 11, 12 are maintained in register with the groove forming rollers 6, 7 such that, when the first o and second continuous webs 1, 15 are laminated as they pass through the laminating station 17, the apertures 14 in the second continuous web 15 align with or adjacent the ends of the groove 9 formed in the first continuous web 1. The resulting cross section of a microfluidic device 25' formed is depicted in Figure 8, with the apertures 14 extending through the thickness of the second web 15 to communicate with the microchannel 29 5 formed by the groove 9.

A sixth embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 9. In the sixth embodiment, the various processing steps are carried out intermittently. The first continuous web 1 is first advanced from the first continuous web supply roller 2 to a groove forming station 5" in 0 the form of a groove forming press having a fixed press base plate 35 and a displaceable die 36 having a groove forming projection 8 protruding therefrom. The first continuous web 1 is stopped when a portion of the first continuous web 1 is located at the groove forming station 5" between the base plate 35 and die 36. The die 36 is driven toward the

base plate 35 so as to press into the adhesive layer 3 of the first continuous web 1, forming a groove 9. The die 36 is then retracted.

The first continuous web 1 is then advanced to the aperture forming station 10". The aperture forming station 10" is in the form of an aperture forming press comprising a base plate 37 and an aperture forming die 38 having two aperture forming punches 13. The first continuous web 1 stops between the base plate 37 and aperture forming die 38, and the aperture forming die 38 is driven towards the base plate 37 so as to cut apertures 14 in the first continuous web 1 at or adjacent each opposing end of the groove 9. The aperture forming die 38 is then retracted. As per the second embodiment, a laser cutting device might be used rather than the aperture forming die 38.

The first continuous web 1 and second continuous web 15 (provided on the second continuous web supply roller 16) are then advanced to a laminating station 17" in the form of opposing heated plates 39, 40. The first and second continuous webs 1, 15 are stopped between the heated plates 39, 40. The heated plates 39, 40 are then driven toward each other so as to laminate the first faces Ia, 15a of the first and second continuous webs 1, 15 before the heated plates 39, 40 are released. The laminated web 20 formed by the laminating process is then advanced to a cutting station 21', which is here in the form of a laser cutting device 31 the same as that of the second embodiment described above in relation to Figure 4. The discrete microfluidic devices 25 are cut from the laminated web 20 at the cutting station 21 ' and drop into a collection receptacle 26. The remaining laminated web 20 is wound onto a receiving roller 27 as described above.

The various stations are arranged such that each of the groove forming, aperture forming, laminating and cutting stations operate on successive portions of the first and second continuous webs 1, 15 each time that the webs are stopped. In a similar manner to the third and fourth embodiments, the groove and aperture forming stations 5" and 10" may either be combined into a single base plate and die or have their positions interchanged such that the groove forming station 5" follows the aperture forming station 10". Also, the aperture forming station 10" may be arranged to form apertures in the second continuous web 15 in a similar manner to the fifth embodiment described above.

A seventh embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted, in part, in Figure 10. The seventh embodiment is a modification of the sixth embodiment described above, with the addition of an electrode

deposition station 41 between the first continuous web supply roller 2 and the groove forming station 5". A mesh screen 42 is applied to the first face Ia of the first continuous web 1. The mesh screen 42 is provided with a mask 43 providing open areas 44. A roller 45 then rolls a metallic paste across the mask 43, and screen 42, depositing metallic films forming electrodes 46, in the shape of each cutout 44, on the first face of the first continuous web 1. The electrode deposition station 41 will be in register in relation to the groove forming station 5" typically such that the electrodes 46 overlap the ends of the groove 9 subsequently formed, enabling the application of a voltage to a liquid located in the microchannel 29, in use. The aperture forming station 10" will typically be arranged to form the apertures 14 in the second continuous web 15, rather than cutting through the electrodes 46 on the first continuous web 1. The electrode deposition station 41 may deposit electrodes each formed of a layer of other conductive material such as carbon film or conductive plastic film.

The electrodes 46 may alternatively be utilised to provide electrical connection between liquids in separate microchannels.

An eighth embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 11. The eighth embodiment is identical to the first embodiment, except that the groove forming projection 8 of the first groove forming roller 6 is arranged to form two grooves 9' that join in a Y-shape, with three aperture forming punches 13 being formed on the first aperture forming roller 11 so as to form three apertures 14 corresponding to the ends of the grooves 9', thereby enabling three separate liquids to be injected into the microchannels 29' formed by the grooves for subsequent mixing and reaction. It is further envisaged that various other arrays of grooves and apertures may be formed, including various s-shape bends as desired so as to form elongate microchannels on a relatively small microfluidic device.

A ninth embodiment of a method and apparatus for continuous formation of microfluidic devices is depicted in Figure 12. In the ninth embodiment, the aperture forming station 10, laminating station 17 and cutting station 21 are identical to those of the first embodiment. The groove forming station 5"', however, is divided into three sub-stations. A sacrificial web 47 is provided on a sacrificial web roller 48 and advanced to a wire locating sub-station 49 where a wire 50 is located between the first continuous web 1 and the sacrificial web 47, typically by a robotic device or similar. The wire 50 may suitably be formed of a length of copper wire having a diameter of the order of 600

micrometres. The first continuous web 1 and sacrificial web 47, with the wire 50 located therebetween, is then passed through an auxiliary laminating sub-station 51 comprising first and second auxiliary heated rollers 52, 53. The auxiliary heated rollers 52, 53 are typically heated to a temperature of approximately 11O ⁰ C. The auxiliary heated rollers 52, 53 laminate the first face Ia of the first continuous web 1 to the sacrificial web 47, with the wire 50 sandwiched therebetween, such that the auxiliary lamination process presses the wire 50 into the adhesive layer 3 of the first continuous web 1, thereby forming a groove 9 in the adhesive layer 3.

The laminated assembly of the first continuous web 1 and sacrificial web 47 then passes to a delamination sub-station 54 where the sacrificial web 47 is delaminated from the first continuous web 1. The delamination sub-station comprises a sacrificial web receiving roller 55 and opposing sharp-edged guides 56, 57 located on opposing sides of the first continuous web 1. The first guide 56 is disposed downstream of the sacrificial web receiving roller 55 adjacent the first continuous web second face Ib. The first continuous web 1 is deflected about the sharp edge of the first guide 56, resulting in the wire 50 peeling from the first face Ia of the first continuous web 1. The beveled sharp edge of the second guide 57 guides the separated leading end of the wire 50 away from the first continuous web 1, thereby ensuring that the wire 50 is removed from the first face Ia of the first continuous web 1, leaving the open groove 9. The first continuous web 1 bearing the groove 9 then advances through the aperture forming station 10, laminating station 17 and cutting station 21 in the same manner as described above in relation to the first embodiment.

Figures 13a to 13b depict formation of the microchannel 29 at various stages through the above described method of the ninth embodiment. Figure 13a depicts the assembly of the first continuous web 1 (comprising the adhesive layer 3 and plastic film 4), wire 50 and sacrificial web 47 between the wire locating sub-station 49 and the auxiliary laminating sub-station 51. Figure 13b depicts the assembly between the auxiliary laminating sub-station 51 and the delaminating sub-station 54. Figure 13c depicts the first continuous web 1 between the aperture forming station 10 and the laminating station 17, particularly showing the groove 9 formed in the adhesive layer 3. Figure 13d depicts the first continuous web 1 and second continuous web 15 immediately prior to the laminating station 17. Figure 13e depicts the laminated web 20 downstream of the laminating station 17, particularly showing the microchannel 29.

The person skilled in the art will appreciate that various features of each of the above described embodiments may be readily interchanged or modified as desired.