Dynamic slot die

Abstract

The present invention relates to a dynamic slot die which includes a die body a fluid inlet, a first portion and a second portion, a manifold in fluid communication with said fluid inlet and formed within said die body, a feed slot formed between said first portion and said second portion configured to deliver coating fluid from the manifold to a substrate, and an adjustment mechanism operable to translate the first portion relative to the second portion such that the feed slot size varies.

Description

DYNAMIC SLOT DIETECHNICAL FIELDThe present invention relates to a dynamic slot die and a coating system comprising a dynamic slot die and a monitoring device.BACKGROUND

[0001] Slot die coating is a widely used technique in various industries for applying thin, uniform layers of material onto a substrate. The process involves the controlled extrusion of a fluid through a narrow, rectangular slot onto a moving substrate. This method is used in manufacturing processes such as the production of batteries, displays, and thin-film solar cells.

[0002] Despite its advantages, traditional slot die coating systems face several challenges that can impact the quality and consistency of the coated layer. These challenges include variations in coating thickness, edge effects, and the occurrence of defects such as streaks or air entrainment.

[0003] Inconsistent flow distribution across the slot and blockages can result in non-uniform coatings. Current solutions while effective to some extent, significantly increase the complexity and cost of the equipment.

[0004] Therefore, there is a need for improvements in slot die technology that can enhance the uniformity of coating. The present invention addresses at least some of the flaws with the prior art.SUMMARY OF INVENTION

[0005] Aspects and embodiments of the invention provide a dynamic slot die, a coating system and a method of use of a dynamic slot die as claimed in the appended claims.

[0006] According to an aspect of the present invention there is provided a dynamic slot die comprising: a die body comprising a fluid inlet, a first portion and a second portion; a manifold in fluid communication with said fluid inlet and formed within said die body; a feed slot formed between said first portion and said second portion configured to deliver coating fluid from the manifold to a substrate; an adjustment mechanism operable to translate the first portion relative to the second portion such that the feed slot size varies.

[0007] The present invention provides a dynamic slot die which can be adjusted prior to or during use to change the size of the feed slot. If the substrate is being monitored, then when the coating uniformity changes the feed slot size can be dynamically varied during use to improve the coating uniformity. In addition, if a blockage is detected by an operative or implied by flow rate variations through the feed slot, then the adjustment mechanism can be used to increase the feed slot size at least until the blockage is relieved, then the adjustment mechanism can return the feed slot to the size before the blockage was detected.

[0008] In an embodiment, the die body further comprises a block within said manifold, wherein said block forms part of said feed slot.

[0009] The block can be used in various ways during a coating procedure, for example choosing an optimised shape or length of the block changes the feed slot and as such varies a parameter of the fluid applied to the substrate such as a width, thickness or shape.

[0010] In an embodiment, the die body includes a recess for said block.

[0011] Forming a recess in the die body ensures that a fluid tight seal can be achieved, preferably the seal can be enhanced using a gasket. Preferably the gasket is formed around a perimeter of the block.

[0012] In an embodiment, the die body includes a raised lip which forms a fluid tight seal with said recess and said block other than at said feed slot.

[0013] In an embodiment, said block protrudes from said die body.

[0014] In embodiments in which the block protrudes from the die body, the block and / or a combination of the block and the gasket can be used as a meniscus guide by protruding from the slot die lips (the end of the feed slot).

[0015] In an embodiment, said block comprises a gasket formed around said block.

[0016] The gasket can be used to provide or enhance a fluid tight seal between the various components of the dynamic slot die and can also be used to form a part of a meniscus guide. The meniscus guide can be used to control and stabilise the liquid meniscus between the slot die and the substrate, enhancing the uniformity of the coating thickness.

[0017] In an embodiment, the gasket is formed of one of nitrile rubber, silicone rubber, polyurethane, fluorocarbon (FKM, FPM,PTFE), compressed fibres.

[0018] In an embodiment, the block is attached to the first portion or the second portion and the other of the first portion and the second portion comprises the fluid inlet.

[0019] In an embodiment, the dynamic slot die comprises a plurality of adjustment mechanisms each being independently operable to alter the relative position and / or angle of the first portion relative to the second portion such that at least one of the shape or volume of the feed slot and / or the manifold varies.

[0020] By varying not just the size of the feed slot but also the shape / angle as well as the size, shape and angle of the manifold the dynamic slot die can be amended to vary the parameters of the fluid flowing from the feed slot during a dispense operation. This includes varying a shape of the feed slot in response to a segment or portion or area of a fluid applied to a substrate being too thin or too thick or having a high variability or decreased uniformity. For example, actuating a first of the plurality of the adjustment mechanisms may be associated with increasing or decreasing a thickness of a certain segment of the fluid being applied and thereby improving a uniformity of the fluid on the substrate.

[0021] In an embodiment, the adjustment mechanism comprises a screw mechanism configured to convert a rotational movement into a linear movement which moves said first portion and said second portion such that they are translated relative to each other.

[0022] A screw mechanism or preferably a plurality of screw mechanisms as the adjustment mechanism allows the user to actuate the adjustment mechanism in a continuous and easily controlled manner. Each of the plurality of screw mechanisms may have the same ratio of rotational to linear movement or some may have greater or lower ratios for different functions. For example, one of the screw mechanisms may have a significantly larger ratio such that a blockage can be removed rapidly.

[0023] In an embodiment, the screw mechanism is configured such that one rotation of the screw mechanism results in less than 5 millimetres of linear movement or less than 1 millimetre of linear movement.

[0024] In an embodiment, at least one of the first portion and second portion includes at least one dowel and the other of the first portion and the second portion includes at least one bore for receiving said dowel.

[0025] By providing a dowel (which may be a cylindrical rod, a square peg, or any other straight rod) along which the first portion / the second portion can travel during relative motion provides a guide for the motion to ensure that the motion is smooth and does not deviate excessively from a predetermined path.

[0026] According to an aspect of the present invention there is provided a coating system for coating a substrate with a fluid comprising the dynamic slot die as described above, the coating system further comprising: a fluid supply connected to said fluid inlet; a positioning mechanism to move the substrate relative to the dynamic slot die and a monitoring device configured to detect a parameter relating to the fluid applied to the substrate.

[0027] Using a monitoring device in concert with the dynamic slot die allows a user or a controller to monitor the flow of fluid being applied to the substrate for changes in the profile, thickness or uniformity. The adjustment mechanism can then be used to return the parameter to the correct value.

[0028] In an embodiment, the parameter is indicative of at least one of a thickness, a profile, a uniformity, a width of the fluid applied to the substrate.

[0029] In an embodiment, the monitoring device is configured to generate a signal when said parameter is exceeding or subceeding (being lower than) a predetermined value.

[0030] In an embodiment, said signal causes a controller to at least one of: generate an alert for a user; increase or decrease the speed of the positioning mechanism; operate the adjustment mechanism.

[0031] In an embodiment, said monitoring device comprises at least one of a vision system, 2D laser trigonometry, optical profilometry, profilometry, ultrasonic thickness measurement, infrared thermography, magnetic thickness gauge, spectroscopic reflectometry, operator visual observation.

[0032] In an embodiment, said monitoring device detects said parameter at a plurality of locations of said fluid on said substrate and causes a controller to operate the adjustment mechanism in response to the parameter varying between said segments to reduce said variation.

[0033] According to an aspect of the present invention there is provided a method of using a dynamic slot die comprising: inserting a fluid via the fluid inlet; using the adjustment mechanism to change the shape of the feed slot.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGSTo easily identify the discussion of any particular element or act, the most significant digit or digits in a reference number refer to the figure number in which that element is first introduced.FIG. 1 illustrates an expanded view of a dynamic slot die in accordance with an embodiment of the present invention.

[0034] FIG. 2 illustrates a first portion of a die body in accordance with one embodiment of the present invention.

[0035] FIG. 3 illustrates a second portion of the die body in accordance with one embodiment of the present invention.

[0036] FIG. 4A illustrates a screw mechanism in accordance with one embodiment of the present invention.

[0037] FIG. 4B illustrates a dowel in accordance with one embodiment of the present invention.

[0038] FIG. 5A illustrates a block in accordance with one embodiment of the present invention.

[0039] FIG. 5B illustrates a gasket in accordance with one embodiment of the present invention.

[0040] FIG. 6 illustrates a coating system in accordance with one embodiment of the present invention.DETAILED DESCRIPTION

[0041] FIG. 1 illustrates a dynamic slot die 100 comprising a first portion 102, and a second portion 104 which together form a die body. The first portion includes a fluid inlet and an internal manifold which fluidly connects the fluid inlet to a feed slot. The second portion 104 includes a plurality of screw mechanisms 108a - 108c which form an adjustment mechanism operable to alter the size and / or shape of a feed slot.

[0042] Screw mechanisms 108b and 108c are offset from a central line which passes through the attachment bore 106 and the feed slot. By rotating one of the adjustment mechanisms more than the other the shape of the feed slot varies. Beneficially, if a left hand side, for example, of the fluid applied to the substrate falls below a required parameter such as thickness, then theleft screw mechanism 108b could be employed to increase the distance between the first portion 102 and the second portion 104 and thereby increasing the size of the feed slot disproportionately at the left side more than the other and as such increase the thickness of the left hand side.

[0043] A plurality of dowels 116a - 116c are provided which move within bores provided in the second portion 104 to maintain alignment between the first and the second portion.

[0044] The feed slot is formed between a block 112 attached to the second portion 104 and a section of the first portion 102 which is bounded by a raised lip 114. A gasket 110 is provided around said block to create a fluid tight seal between the first portion and the second portion.

[0045] Retainer bolts 118a & 118b may be used to attach an elastomeric retainer to the dynamic slot die 100. The elastomeric retainer is used to oppose the movement of the first and second portions away from each other with tension generated in the retainer as they move apart. Further retainer bolts and a further elastomeric retainer may be present on the opposing side of the die body to the retainer bolts 118a & 118b.

[0046] Other associated coating equipment can be mounted to the dynamic slot die 100 using attachment bore 106 or the dynamic slot die may be mounted upon said other equipment. To prevent the screw mechanism 108a - 108c from sliding away from the die body a grub screw 120a, 120b is used to retain each of the screw mechanisms. A further grub screw may be present for the remaining screw mechanism.

[0047] The block 112 is held in place by a block retainer 122 which may be one or more bolts, screws or other retaining means.

[0048] FIG. 2 illustrates the first portion 102 in accordance with an embodiment of the present invention. The first portion 102 includes a plurality of dowel bores 202a - 202d for accepting the plurality of dowels 116a - 116c. The first portion 102 includes a fluid inlet for accepting fluid from a hose or tube. The fluid inlet is in fluid communication with a fluid bore 204 via a manifold within the first portion. The raised lip 114 and the block 112 create a fluid volume which is in fluid communication with the fluid bore 204. The fluid inlet may be located on the opposing side of the first portion 102 with a manifold connecting the fluid inlet to the fluid bore 204. The volume and the shape of the fluid volume varies as the first and second portion move relative to each other.

[0049] FIG. 3 illustrates a second portion 104 comprising a recess 302 for accepting the block112 and an attachment recess 304 which accommodates attachment means which attach theblock 112 within the recess 302. The second portion 104 includes a plurality of screw mechanism bores 306a - 306c which accept a spindle or linear actuator 402 of the screw mechanism(s) as well as a plurality of dowel bores 308a - 308c.

[0050] FIG. 4A illustrates a screw mechanism 400 according to an embodiment of the present invention which converts a rotation of the thimble 404 into a linear movement of a linear actuator 402 or spindle. The screw mechanism 400 includes a scale 406 and rotation of the thimble 404 drives the linear actuator 402. The screw mechanism 400 which forms at least a part of the adjustment mechanism may be a micrometre configured such that one rotation of the screw mechanism results in less than 5 millimetres of linear movement or less than 1 millimetre of linear movement.

[0051] FIG. 4B illustrates a dowel 408 in accordance with an embodiment of the present invention. The dowel 408 may have a radius which is smaller than a radius of the dowel bores such that the dowel can slide within the dowel bore and such that the first portion and the second portion can be at an angle relative to each other. The shape and size of the dowel 408 may be configured such that the feed slot can be changed in size and shape by a predetermined maximum amount.

[0052] FIG. 5A illustrates a block 502 which is attached to the second portion of the die body. The block 502, in conjunction with the raised lip forms a volume which extends the manifold through which the fluid flows during use of the dynamic slot die. The block 502 includes a gasket receiving groove 504 for a gasket 110 which is retained by the gasket receiving groove 504 to form a fluid tight seal between the block 502 and the raised lip.

[0053] The block 502 includes an attachment portion 506 which has a number of bores 508a & 508b equal to the number of block retainers 122.

[0054] A meniscus guide 510 is used to control the meniscus of the fluid being applied to the substrate. The meniscus is the curve seen at the edge of the fluid surface, resulting from surface tension. The meniscus guide 510 helps stabilize this curve by confining the flow to a precise area and preventing unwanted spreading or fluctuations. The meniscus guide 510 helps prevent coating defects such as streaks, waves, or air bubbles that can occur if the meniscus becomes unstable or irregular.

[0055] FIG. 5B illustrates a gasket 110 which is generally in the shape of the gasket receiving groove 504 and is used to create a fluid tight seal between the raised lip and the block 112.

[0056] FIG. 6 shows a coating system 600 which includes the dynamic slot die 100 as described above. The coating system 600 includes a fluid supply 602 which provides the fluid 612 to be applied to the substrate 606 to the fluid inlet of the dynamic slot die 100.

[0057] The substrate 606 is moved into position by a positioning mechanism 610 which moves in a direction of travel 608.

[0058] The coating system 600 further includes a monitoring device 604 which may include at least one of a vision system, 2D laser trigonometry, optical profilometry, profilometry, ultrasonic thickness measurement, infrared thermography, magnetic thickness gauge, spectroscopic reflectometry.

[0059] The monitoring device 604 may be a plurality of monitoring devices which monitor a parameter of the fluid 612 applied to the substrate 606. The parameter may be one of a thickness, a profile, a uniformity, a width of the fluid applied or being applied to the substrate. The parameter may be monitored continuously or discretely and variations in the parameter may cause a signal or a alarm to be generated when the parameter exceeds, subceeds or varies by a predetermined value. The signal generated may vary used by a controller to vary the adjustment mechanism in order to change a size or shape of the feed slot and the internal volume in order to vary the flow rate and flow characteristics of the fluid.

[0060] All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0061] Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0062] The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed. The claims should not be construed to cover merely the foregoing embodiments, but also any embodiments which fall within the scope of the claims.

[0063] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0064] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0065] The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.The following list of clauses should not be confused with the claims.1. A dynamic slot die comprising: a die body comprising a fluid inlet, a first portion and a second portion; a manifold in fluid communication with said fluid inlet and formed within said die body; a feed slot formed between said first portion and said second portion configured to deliver coating fluid from the manifold to a substrate; an adjustment mechanism operable to translate the first portion relative to the second portion such that the feed slot size varies.2. The dynamic slot die of clause 1 wherein the die body further comprises a block within said manifold, wherein said block forms part of said feed slot.3. The dynamic slot die of clause 1 or 2 wherein the die body includes a recess for said block.4. The dynamic slot die of clause 3 wherein the die body includes a raised lip which forms a fluid tight seal with said recess and said block other than at said feed slot.5. The dynamic slot die of any one of clauses 2 to 4 wherein said block protrudes from said die body.6. The dynamic slot die of any one of clauses 2 to 5 wherein said block comprises a gasket formed around said block.7. The dynamic slot die of any one of clauses 1 to 6 wherein the block is attached to the first portion or the second portion and the other of the first portion and the second portion comprise the fluid inlet.8. The dynamic slot die of any one of clauses 1 to 7 comprising a plurality of adjustment mechanisms each being independently operable to alter the relative position and / or angle of the first portion relative to the second portion such that at least one of the shape or volume of the feed slot and / or the manifold varies.9. The dynamic slot die of any one of clauses 1 to 8 wherein the adjustment mechanism comprises a screw mechanism configured to convert a rotational movement into a linear movement which moves said first portion and said second portion such that they are translated relative to each other.10. The dynamic slot die of clause 9 wherein the screw mechanism is configured such that one rotation of the screw mechanism results in less than 5 millimetres of linear movement or less than 1 millimetre of linear movement.11. The dynamic slot die of any one of clauses 1 to 10 wherein at least one of the first portion and second portion includes at least one dowel and the other of the first portion and the second portion includes at least one bore for receiving said dowel.12. A coating system for coating a substrate with a fluid comprising the dynamic slot die of any preceding clause, the coating system further comprising: a fluid supply connected to said fluid inlet; a positioning mechanism to move the substrate relative to the dynamic slot die anda monitoring device configured to detect a parameter relating to the fluid applied to the substrate.13. The coating system of clause 12 wherein the parameter is indicative of at least one of a thickness, a profile, a uniformity, a width of the fluid applied to the substrate.14. The coating system of clause 12 or 13 wherein the monitoring device is configured to generate a signal when said parameter is exceeding or subceeding a predetermined value.15. The coating system of clause 14 wherein said signal causes a controller to at least one of: generate an alert for a user; increase or decrease the speed of the positioning mechanism; operate the adjustment mechanism.16. The coating system of any one of clauses 12 to 15 wherein said monitoring device comprises at least one of a vision system, 2D laser trigonometry, optical profilometry, profilometry, ultrasonic thickness measurement, infrared thermography, magnetic thickness gauge, spectroscopic reflectometry.17. The coating system of any one of clauses 12 to 16 wherein said monitoring device detects said parameter at a plurality of locations of said fluid on said substrate and causes a controller to operate the adjustment mechanism in response to the parameter varying between said segments to reduce said variation.18. A method of using the dynamic slot die of any of clauses 1 to 11 or the coating system of any of clauses 12 to 17 comprising: providing a substrate to be coated; inserting a fluid via the fluid inlet; using the adjustment mechanism to change the shape of the feed slot.

Claims

CLAIMS1. A dynamic slot die comprising: a die body comprising a fluid inlet, a first portion and a second portion; a manifold in fluid communication with said fluid inlet and formed within said die body; a feed slot formed between said first portion and said second portion configured to deliver coating fluid from the manifold to a substrate; an adjustment mechanism operable to translate the first portion relative to the second portion such that the feed slot size and / or the manifold volume varies.

2. The dynamic slot die of claim 1 wherein the die body further comprises a block within said manifold, wherein said block forms part of said feed slot.

3. The dynamic slot die of claim 1 or 2 wherein the die body includes a recess for said block.

4. The dynamic slot die of claim 3 wherein the die body includes a raised lip which forms a fluid tight seal with said recess and said block other than at said feed slot.

5. The dynamic slot die of any one of claims 2 to 4 wherein said block protrudes from said die body.

6. The dynamic slot die of any one of claims 2 to 5 wherein said block comprises a gasket formed around said block.

7. The dynamic slot die of any one of claims 2 to 6 wherein the block is attached to the first portion or the second portion and the other of the first portion and the second portion comprise the fluid inlet.

8. The dynamic slot die of any one of claims 1 to 7 comprising a plurality of adjustment mechanisms each being independently operable to alter the relative position and / or angle of the first portion relative to the second portion such that at least one of the shape or volume of the feed slot and / or the manifold varies.

9. The dynamic slot die of any one of claims 1 to 8 wherein the adjustment mechanism comprises a screw mechanism configured to convert a rotational movement into a linearmovement which moves said first portion and said second portion such that they are translated relative to each other.

10. The dynamic slot die of claim 9 wherein the screw mechanism is configured such that one rotation of the screw mechanism results in less than 5 millimetres of linear movement or less than 1 millimetre of linear movement.

11. The dynamic slot die of any one of claims 1 to 10 wherein at least one of the first portion and second portion includes at least one dowel and the other of the first portion and the second portion includes at least one bore for receiving said dowel.

12. A coating system for coating a substrate with a fluid comprising the dynamic slot die of any preceding claim, the coating system further comprising: a fluid supply connected to said fluid inlet; a positioning mechanism to move the substrate relative to the dynamic slot die and a monitoring device configured to detect a parameter relating to the fluid applied to the substrate.

13. The coating system of claim 12 wherein the parameter is indicative of at least one of a thickness, a profile, a uniformity, a width of the fluid applied to the substrate.

14. The coating system of claim 12 or 13 wherein the monitoring device is configured to generate a signal when said parameter is exceeding or subceeding a predetermined value.

15. The coating system of claim 14 wherein said signal causes a controller to at least one of: generate an alert for a user; increase or decrease the speed of the positioning mechanism; operate the adjustment mechanism.

16. The coating system of any one of claims 12 to 15 wherein said monitoring device comprises at least one of a vision system, 2D laser trigonometry, optical profilometry, profilometry, ultrasonic thickness measurement, infrared thermography, magnetic thickness gauge, spectroscopic reflectometry.

17. The coating system of any one of claims 12 to 16 wherein said monitoring device detects said parameter at a plurality of locations of said fluid on said substrate and causes a controllerto operate the adjustment mechanism in response to the parameter varying between said segments to reduce said variation.

18. A method of using the dynamic slot die of any of claims 1 to 11 or the coating system of any of claims 12 to 17 comprising: providing a substrate to be coated; inserting a fluid via the fluid inlet; using the adjustment mechanism to change the shape of the feed slot.

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