Precision feed and guide system for sub-100 micron thickness metal foil sheets

Abstract

The present disclosure relates to the manufacture of expanded metal mesh, and more particularly to a novel feed and guide system which may be used for advancing (pushing) very thin metal foil sheets (about 12.5μm to about 100μm thickness) in a metal foil expanding apparatus.

Description

Docket P04124-WO2ORD

[0001] TITLE

[0002] PRECISION FEED AND GUIDE SYSTEM FOR SUB-100 MICRON THICKNESS METAL FOIL SHEETS

[0003] BACKGROUND OF THE DISCLOSURE

[0004] (1) Field of the Invention: The instant invention generally relates to the manufacture of expanded metals, and more particularly to a novel feed and guide system for advancing sub- 100 micron thickness (<100pm) metal foil sheets in an expanding machine.

[0005] (2) Description of Related Art: Metal expanding is a metal forming process initially developed in 1884 in which a blade with defined tooth pitch reciprocates up and down and left and right, to slit a metal sheet and create predictable, repeatable well-defined openings as the metal sheet advances through the expander (see Fig. 1).

[0006] Expanded metal has diverse applications as structural components, energy absorbing materials, filters, and electrodes for battery applications. Properties include high strength and rigidity, mass efficiency, and high porosity. Expanded metal is highly economical due to its production directly from sheet metal with near zero waste material. For this reason, in addition to the predictable, repeatable nature of expanded metal openings, components utilizing metal foam, porous sinters, or woven metal wire often become replaced by expanded-metal components when possible.

[0007] At present, standard expanding technology is limited to expanding blades having a tooth pitch down to about 1 mm.

[0008] As metal expanding techniques progress to smaller pore sizes and thinner metal sheets and foils, there is a need for a precision feed and guide system that can handle the unique dynamic characteristics of advancing very thin metal foils in an expanding machine.

[0009] SUMMARY OF THE DISCLOSURE

[0010] The instant invention relates to the manufacture of expanded metal mesh, and more particularly to a novel feed and guide system which may be used for advancing (pushing) very thin metal foil sheets (about 12.5qm to about lOOqm thickness) in a metal foil expanding apparatus.Docket P04124-WO2ORD

[0011] Titanium is identified herein as an exemplary material, but it should be understood that the disclosure and system are applicable to any metal foil with the same dimensional thicknesses.

[0012] As can be appreciated by one skilled in the art, the subject thin foils will be expanded with sub-millimeter size tooth blades for very small pore sizes and thus advanced in small increments for uniform hole or pore distribution. In the present disclosure, it is contemplated that the metal foil materials may need to be advanced in increments between about 10pm and about 100pm with about 0.1pm accuracy.

[0013] The expanding mechanism generally comprises a stationary lower blade mount and lower fixed blade paired with a toothed upper blade held in a reciprocating expanding head which moves up and down and side to side (see arrows) cooperating with the fixed lower blade to expand a metal sheet passing through the expanding head.

[0014] The feed and guide system may comprise a lower drive roller paired with an upper follower roller, upper and lower forward guide platens cooperating to define a forward guide channel forward of the roller pair, and upper and lower rearward guide platens cooperating to define a rearward guide channel leading into the roller pair.

[0015] The drive and follower rollers comprise ultra-thin titanium drum walls (low inertia)designed to reduce weight and associated rotational inertia. Because the foil materials are so thin, any slight movement of the foil that is not intended will affect expanding accuracy and pore opening distribution.

[0016] The bottom roller is driven to advance (or push) the foil sheet through the guide platens by an ironless core motor which has virtually or entirely no backlash or inertia. The rotor core does not contain any iron, resulting in a lightweight, low inertia design that provides high acceleration and smooth motion, ideal for applications requiring precise and dynamic movement. The coreless motor eliminates "cogging" effects and allows for high speeds and accuracy.

[0017] The forward and rearward guide platen assemblies are constructed in relatively the same configuration, albeit in reverse orientation to closely align with the input and output sides of the drive rollers.

[0018] The lower forward and rearward guide platens are fixed in position on opposing output and input sides of the drive roller. The trailing and leading edges adjacent to the drive rollerDocket P04124-WO2ORDmirror the circumferential profile of the roller for a close fit and create a very narrow nip opening therebetween in which the foil material is engaged by the rollers.

[0019] The upper forward and rearward guide platens are seated into the guide channels and have peripheral side shoulder portions which overlap the sidewalls of the lower guide platens. The trailing and leading edges adjacent to the upper follower roller mirror the circumferential profile of the roller for a close facing fit and create a very narrow nip opening therebetween in which the foil material is engaged by the rollers. This interfitting arrangement creates a narrow guide slot to guide the metal foil therein and allows the upper guide platens to slide along the feed axis relative to the lower platens.

[0020] To initially feed the metal foil into the nip, the upper platens are removed for access to the guide channel on both the input and output sides of the nip. Reassembly of the upper platens in the proper spaced locations is critical to functionality, and in this regard, the system provides an alignment system to insure repeatability of the assembly position of the upper guide platens.

[0021] To insure the upper platens are normally biased downward and toward the rollers, the upper surfaces of the sidewalls of the lower platens and the lower surfaces of the shoulder portions of the upper platens are provided with magnet pairs wherein the opposing magnetic poles are axially offset to create a biased attraction of the upper platens toward the drive rollers. To set the upper platen locations, i.e. fix or stop forward / rearward movement of the upper platens, each upper and lower platen pair is provided with symmetric adjustment stops on each side of the guide channels (adjacent the magnets). In each of the side walls of the lower platens, a 254 thread per inch adjustment screw is seated in threaded bushing which is set in a longitudinal bore in the end wall. The end of the adjustment screw includes a stop flange at the terminal end thereof. An adjustment key extends through the upper platen into a slotted opening in the upper surface of the lower platen sidewall into the interior of the longitudinal bore where it can engage with the stop flange.

[0022] In operation, the upper platen is biased toward the roller until the key engages the stop flange. Rotation of the adjustment screw moves the stop flange forward and rearward to set the biased position of the upper platen. Each full rotation of the adjustment screw provides (,1mm or 100pm) of linear adjustment and a near infinite adjustability with less than full rotations.Docket P04124-WO2ORD

[0023] BRIEF DESCRIPTION OF THE DRAWING FIGURES

[0024] While the specification concludes with claims particularly pointing out and distinctly claiming particular embodiments of the instant invention, various embodiments of the invention can be more readily understood and appreciated from the following descriptions of various embodiments of the invention when read in conjunction with the accompanying drawings in which:

[0025] Fig. 1 is an illustration of an exemplary metal mesh expanding apparatus;

[0026] Fig. 2 is a cross-sectional illustration of the feed and guide system of the present invention for feeding a metal foil to a reciprocating expanding head;

[0027] Figs. 3-5 are perspective illustrations of the feed and guide system from various viewing angles;

[0028] Fig. 6 is an exploded perspective illustration of the feed and guide system;

[0029] Fig. 7 is a top view illustration thereof;

[0030] Fig. 8 is a cross-sectional view thereof taken along line 8-8 of Fig. 7 and illustrating one of the internal platen alignment mechanisms along with the biasing magnet pairs;

[0031] Fig. 9 is a perspective illustration of a threaded adjustment stops of the alignment mechanism; and

[0032] Figs. 10, 10A and 10B are enlarged illustrations of the ramped entry slot between the upper and lower rear platens.

[0033] DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0034] Certain exemplary embodiments will now be described to provide an overall understanding of the principles of the structure, function, manufacture, and use of the device and methods disclosed herein. One or more examples of these embodiments are illustrated in the accompanying drawings. Those skilled in the art will understand that the devices and methods specifically described herein and illustrated in the accompanying drawings are nonlimiting exemplary embodiments and that the scope of the present invention is defined solely by the claims. The features illustrated or described in connection with one exemplary embodiment may be combined with the features of other embodiments. Such modifications and variations are intended to be included within the scope of the present disclosure. Further, in the present disclosure, like-numbered components of the embodiments generally haveDocket P04124-WO2ORDsimilar features, and thus within a particular embodiment each feature of each like-numbered component is not necessarily fully elaborated upon. Additionally, to the extent that linear or circular dimensions are used in the description of the disclosed systems, devices, and methods, such dimensions are not intended to limit the types of shapes that can be used in conjunction with such systems, devices, and methods. A person skilled in the art will recognize that an equivalent to such linear and circular dimensions can easily be determined for any geometric shape. Further, to the extent that directional terms like top, bottom, up, or down are used, they are not intended to limit the systems, devices, and methods disclosed herein. A person skilled in the art will recognize that these terms are merely relative to the system and device being discussed and are not universal.

[0035] Unless otherwise specified, when referring to a numerical value, the term “about” is intended to be construed as including a range of values within + / -10% of the value being referred to.

[0036] Referring now to Figs. 1-10B, the instant invention relates to the manufacture of expanded metal mesh, and more particularly to a novel feed and guide system generally indicated at 10 which may be used for advancing (pushing) very thin metal foil sheets (12.5pm to 100pm thickness) (see exemplary metal sheet generally illustrated in Fig. 1) in an expanding machine.

[0037] Titanium metal is identified herein as an exemplary material for the metal foil sheets, but it should be understood that the disclosure and system are applicable to any metal foil with the same dimensional thicknesses.

[0038] As can be appreciated by one skilled in the art, the subject thin foils may be expanded with sub-millimeter size toothed blades for very small pore sizes and thus advanced in small increments for uniform hole or pore distribution. In the present disclosure, it is contemplated that the metal foil materials may need to be advanced in increments between about 10pm and about 100pm with 0.1pm accuracy.

[0039] An arrangement of an exemplary expanding mechanism 100 and the present feed and guide system 10 are illustrated in a cross-sectional view in Fig. 2. The expanding mechanism 100 generally comprises a stationary lower blade mount 102 and fixed blade 104 paired with a toothed upper blade 106 mounted on a reciprocating head 108 which moves up and down andDocket P04124-WO2ORDside to side (see arrows) cooperating with the fixed blade 104 to expand a metal sheet (not shown) passing through the expanding mechanism.

[0040] Referring to Fig. 3-7, the feed and guide system 10 may comprise a lower drive roller 12 paired with an upper follower roller 14, upper and lower forward guide platens 16, 18 cooperating to define a forward guide channel 20 forward of the roller pair, and upper and lower rearward guide platens 22, 24 cooperating to define a rearward guide channel 26 leading into the roller pair (See Fig. 6).

[0041] The drive and follower rollers 12, 14 comprise ultra-thin titanium drum walls to reduce weight and associated inertia from rotation. Because the foil materials are so thin, any slight movement of the foil that is not intended will affect expanding accuracy. The bottom roller 12 is driven to advance (or push) the foil through the guide 20, 26 by an ironless core motor 28 which has very little to no backlash or inertia (See Fig. 7). The rotor core does not contain any iron, resulting in a lightweight, low inertia design that provides high acceleration and smooth motion, ideal for applications requiring precise and dynamic movement. The coreless motor 28 eliminates "cogging" effects and allows for high speeds and accuracy. Exemplary ironless core motors 28 are available from Maxon Motorstm.

[0042] The forward and rearward guide platen assemblies are constructed in relatively the same configuration, albeit in reverse orientation to closely align with the input and output sides of the drive rollers.

[0043] The lower forward and rearward guide platens 18, 24 are fixed in position on opposing output and input sides of the roller pair 12, 14. The trailing and leading edges 18A, 24A adjacent to the drive roller pair 12, 14 mirror the circumferential profile of the roller 12 for a close fit and create a very narrow nip opening therebetween in which the foil material is engaged by the rollers 12, 14.

[0044] The upper forward and rearward guide platens 16, 22 are received over the lower platens 18, 24 and have peripheral interfitting side shoulder portions which overlap the sidewalls of the lower guide platens 18, 24. The trailing and leading edges 16A, 22A adjacent to the upper follower roller 14 mirror the circumferential profile of the roller 14 for a close facing fit and create a very narrow nip opening therebetween in which the foil material is engaged by the rollers. This interfitting arrangement creates a narrow guide slot to guide the metal foil thereinDocket P04124-WO2ORDand allows the upper guide platens 16, 22 to linearly slide along the foil feed path relative to the lower platens 18, 24.

[0045] In order to initially feed the metal foil into the nip, the upper platens 16, 22 will need to be removed for access to the guide channels 20, 26 on both sides of the nip (See Fig. 6). The foil cannot be fed from the input end. Reassembly of the upper platens 16, 22 in the proper spaced locations will be critical to functionality. In this regard, the system provides an alignment system to insure repeatability of the proper assembly position of the upper guide platens 16, 22.

[0046] Referring now to Figs. 8 and 9, to insure the upper platens 16, 22 are normally biased downward and toward the rollers 12, 14 , the upper surfaces of the sidewalls of the lower platens 18, 24 and the lower surfaces of the shoulder portions of the upper platens 16, 22 are provided with magnet pairs 30A, 30B wherein the opposing magnetic poles are axially offset to create a biased attraction of the upper platens 16, 22 toward the drive rollers 12, 14 (See Fig. 8) (8 sets of magnets in total with two pair on each side of the guide platens, both front and rear). Fig. 8 represents one of the four alignment systems with 2 sets of magnets 30.

[0047] To set the location, i.e. fix or stop forward / rearward movement of the upper platens 16,22, each upper and lower platen pair is provided with symmetric adjustment stops generally indicated at 32 on each side of the guide channels (adjacent the magnets 30).

[0048] In each of the side walls of the lower platens 18, 24, a 254 Thread Per Inch (TPI)adjustment screw 34 is seated in threaded bushing 36 which is set in a longitudinal bore 38 in the end wall. The end of the adjustment screw 34 includes a stop flange 40 at the terminal end thereof. An adjustment key 42 extends through the upper platen 16, 22 into a slotted opening in the upper surface of the lower platen 18, 24 into the interior of the longitudinal bore 38 where it can engage with the stop flange 40. The adjustment screw may have a TPI range of 100 TPI to 300 TPI to provide precise linear adjustment.

[0049] In operation, the upper platens 16, 22 is / are biased toward the rollers 12,14 until the key(s) 42 engages the stop flange(s) 40. Rotation of the adjustment screw 34 moves the stop flange 40 forward and rearward to set the desired biased position of the upper platen(s) 16, 22. Each full rotation of the 254 TPI adjustment screw 34 provides (,1mm or 100pm) of linear adjustment and a near infinite adjustability with less than full rotations.Docket P04124-WO2ORD

[0050] Referring to Fig. 10, the rearward guide channel 26 in the model as illustrated has a height of 25pm with a ramped entry gap of 303 pm. Dimensional aspects of the guide channel and entry gap may vary with the thickness of the foil being utilized.

[0051] While there is shown and described herein certain specific structures embodying various embodiments of the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.

Claims

Docket P04124-WO2ORDWhat is claimed is:

1. A feed and guide system for sub- 100 micron metal foils comprising:a lower drive roller paired with an upper follower roller;an ironless core drive motor coupled to the lower drive roller;a lower forward fixed guide platen;an upper forward guide platen slidably movable relative to the lower forward fixed guide platen along a foil feed path, said upper and lower forward guide platens interfitting and cooperating to define a forward output guide channel forward of the roller pair,a lower rearward fixed guide platen;an upper rearward guide platen slidably movable relative to the lower rearward fixed guide platen along the foil feed path, said upper and lower rearward guide platens interfitting and cooperating to define a rearward input guide chanel rearward of the roller pair, wherein the upper forward and rearward guide platens are removable from the lower forward and rearward guide platens for initial feeding of a foil sheet into the guide channels, a plurality of complementary magnet pairs mounted in corresponding facing relation in opposing surfaces of the upper and lower, forward and rearward guide platens wherein opposing magnetic poles of the complementary magnet pairs are axially offset to create a biased attraction of the forward and rearward upper platens toward the rollers; and symmetric left and right adjustment stops in each of the forward and rearward upper and lower guide platens to fix respective forward and rearward sliding movement of the upper guide platens relative to the lower guide platens.

2. The feed and guide system of claim 1, wherein trailing and leading edges of the guide platens mirror a circumferential profile of the corresponding moted drive or follower roller.

3. The feed and guide system of claim 1, wherein each of the adjustment stops comprises a threaded adjustment screw with a stop flange mounted in the lower guide platen and an associated key received in the upper guide platen configured and arranged to engage with the stop flange of the adjustment screw.Docket P04124-WO2ORD4. The feed and guide system of claim 2, wherein each of the adjustment stops comprises a threaded adjustment screw with a stop flange mounted in the lower guide platen and an associated key received in the upper guide platen configured and arranged to engage with the stop flange of the adjustment screw.

5. The feed and guide system of claim 3 wherein the threaded adjustment screw includes at least 100 threads per inch.

6. The feed and guide system of claim 5 wherein the threaded adjustment screw includes at least 200 threads per inch.

7. The feed and guide system of claim 4 wherein the threaded adjustment screw includes at least 100 threads per inch.

8. The feed and guide system of claim 7 wherein the threaded adjustment screw includes at least 200 threads per inch.

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