System and method for screen of fibrous component forming mold

Abstract

A method of forming a forming mold screen includes providing a mold plate defining a plate profile and a mold center point. And the screen is arranged on the mold plate. A retainer plate secured to the mold plate defines an opening having a retainer center point substantially aligned with the mold center point. A screen is disposed between the mold plate and the retainer plate and substantially defines a plane. A nested punch unit inserted into the opening includes an inner punch and an outer punch disposed around the inner punch. The inner and outer punches are aligned along an axis that is substantially aligned with the retainer plate center point. Pressing the screen with the nested punch unit includes pressing the screen with an inner punch and then pressing the screen with an outer punch.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application was filed as a PCT international application on June 13, 2023, and claims the benefit and priority of U.S. patent application No. 63 / 352,819 filed on June 16, 2022, and claims the benefit and priority of U.S. patent application No. 63 / 358,338 filed on July 5, 2022, the disclosures of which are incorporated herein by reference in their entirety.

[0003] introduce

[0004] Pollution caused by single-use plastic containers and packaging materials is now a recognized global problem. Replacing single-use packaging with biodegradable and compostable materials has been proposed as a way to reduce plastic pollution. However, for a new environmentally friendly alternative to be successful, it must be competitive with the existing plastic technology it is replacing, both in terms of cost and performance.

[0005] As a quick background, molded pulp (also called molded fiber) has been used to make containers, pallets, and other packaging since the 1930s. Pulp can be produced from recycled materials, such as old newsprint and corrugated boxes, or it can be produced directly from trees and other plant fibers. Today, molded pulp packaging is widely used in electronics, household goods, automotive parts, medical products, and food packaging.

[0006] The mold is made by machining a metal tool into the mirror image of the finished part. Holes are drilled into the tool and a screen is then mounted on its surface. A vacuum is drawn through the holes while the screen prevents pulp from clogging the holes. Damage to the screen during its formation can cause pulp to be drawn into the vacuum holes and adversely affect the process and the finished part. Summary of the invention

[0007] On the one hand, the technology relates to a method for forming a forming mold screen, the method comprising: providing a mold plate, the mold plate defining a plate contour and a mold center point; setting the screen on the mold plate; fixing a retainer plate to the mold plate, wherein the retainer plate defines an opening, the opening having a retainer center point substantially aligned with the mold center point, and wherein the screen is set between the mold plate and the retainer plate, and wherein the screen substantially defines a plane; inserting a nested punch unit into the opening, wherein the nested punch unit includes an inner punch and an outer punch arranged around the inner punch, and wherein the inner punch and the outer punch are aligned along an axis substantially aligned with the retainer center point; and pressing the screen using the nested punch unit, wherein pressing the screen with the nested punch unit includes pressing the screen with the inner punch and then pressing the screen with the outer punch. In an example, the nested punch unit includes at least one intermediate punch disposed between the inner punch and the outer punch, and wherein pressing the screen with the nested punch unit includes pressing the screen with at least one intermediate punch after pressing the screen with the inner punch and before pressing the screen with the outer punch. In another example, pressing the screen with the nested punch unit includes moving the inner punch toward the plate contour while substantially maintaining the position of the outer punch relative to the plate contour. In yet another example, pressing the screen with the nested punch unit includes deforming the interior of the screen with the inner punch. In yet another example, pressing the screen with the nested punch unit includes maintaining pressure on the screen with the inner punch while deforming the screen with the outer punch.

[0008] In another example of the above aspects, pressing the screen using the nested punch unit includes bottoming the inner punch against the screen and the die plate before pressing the screen with the outer punch. In an example, bottoming the inner punch substantially prevents the inner punch from further deforming the screen. In another example, the nested punch unit includes a pressing profile that is substantially similar to the plate profile. In yet another example, pressing the screen using the nested punch unit includes bottoming the outer punch against the screen and the die plate. In yet another example, the method also includes removing the screen from between the retainer plate and the die plate, and trimming the screen.

[0009] In another aspect, the technology relates to a method for deforming a substantially flat screen, the method comprising: disposing a substantially flat screen between a die plate including a profile and a retainer plate defining an opening, the opening having a retainer center point substantially aligned with a center point of the profile; and sequentially deforming the screen with a plurality of punches, wherein the plurality of punches are substantially centered along an axis aligned with the center point of the profile, and wherein the plurality of punches include an inner punch and an outer punch, and wherein the inner punch deforms the screen first, and wherein the outer punch deforms the screen last. In an example, the method further comprises applying pressure to the screen with the inner punch during the deformation of the screen by the outer punch. In another example, the pressure applied by the inner punch to the screen is at least partially applied by a first spring. In yet another example, the first spring biases the inner punch away from the outer punch. In another example, the plurality of punches further comprises an intermediate punch between the inner punch and the outer punch, and wherein the intermediate punch deforms the screen after the inner punch and before the outer punch.

[0010] In another example of the above aspects, the method further includes applying pressure to the screen with the intermediate punch during the process of the outer punch deforming the screen. In an example, the pressure applied by the intermediate punch to the screen is at least partially applied by the second spring. In another example, the second spring biases the intermediate punch away from the outer punch.

[0011] In another aspect, the technology relates to a system for deforming a screen, the system comprising: a die plate defining a profile and a die center point; a retainer plate defining an opening having a retainer center point substantially aligned with the die center point; and a nested punch unit comprising an inner punch, an outer punch disposed about the inner punch, and a first spring biasing the inner punch away from the outer punch, wherein the inner punch and the outer punch are aligned along an axis substantially aligned with the retainer center point, wherein the nested punch unit comprises a deforming surface that is substantially a mirror image of the profile. In an example, the inner punch is at least partially slidably engaged with the outer punch. In another example, the nested punch unit further comprises: at least one intermediate punch disposed between the inner punch and the outer punch, a second spring biasing the intermediate punch away from the outer punch, and wherein the first spring biases the inner punch away from the intermediate punch; in yet another example, the inner punch is at least partially slidably received by the intermediate punch, and the intermediate punch is at least partially slidably received in the outer punch. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Various aspects of at least one example will be discussed below with reference to the accompanying drawings, which are not drawn to scale. The drawings are included to provide illustration and further understanding of the various aspects and examples, and are incorporated into and constitute a part of the specification, but are not intended to limit the scope of the particular examples. The drawings and the rest of the specification are used together to explain the principles and operations of the various aspects and examples described and claimed. In the drawings, each identical or nearly identical component shown in each figure is represented by the same reference numeral. For clarity, not every component will be labeled in every figure.

[0013] Figure 1A and Figure 1B A perspective view and a partially enlarged perspective view of a forming mold of a molded fiber component manufacturing system are respectively shown.

[0014] Figure 2A and Figure 2B An exploded perspective view and an exploded cross-sectional perspective view of a system for deforming a screen are shown, respectively.

[0015] Figure 2C A cross-sectional view of a nested punch unit is shown.

[0016] Figures 3A-3H Example systems for deforming a screen and methods of deforming a screen are shown.

[0017] Figures 4A-4E Another example system for deforming a screen and method of deforming a screen are shown.

[0018] Figure 5 A method of forming a forming die screen is shown.

[0019] Figure 6 Another method of forming a forming die screen is shown.

[0020] Fig. 6A Shown with Figure 6 Optional operations related to the method shown. DETAILED DESCRIPTION

[0021] Before disclosing and describing a production line for producing a molded fiber product, it should be understood that the present disclosure is not limited to the specific structures, process steps or materials disclosed herein, but also extends to equivalents recognized by ordinary technicians in the relevant art. It must be noted that, as used in this specification, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a "step" or "operation" may include multiple steps or operations, and reference to the "production" or "product" of a step or operation should not be considered to be all products.

[0022] Various embodiments of the technology described below relate to the manufacture of fiber-based or pulp-based products for use within and outside the food and beverage industries. The fiber-based products are suitable for replacing their plastic counterparts in a wide variety of applications, such as: frozen, refrigerated, and non-refrigerated foods; medical, pharmaceutical, and biological applications; microwaveable food containers; beverages; edible and non-edible liquids; materials that release water, oils, and / or water vapor during storage, transportation, and preparation (e.g., cooking); horticultural applications, including consumables and landscape / gardening plants, flowers, herbs, shrubs, and trees; single-use or disposable storage and dispensing utensils (e.g., paint trays, food trays, brush handles, shipping protective covers); products (including human and animal food such as fruits and vegetables); salads; prepared foods; packaging for meat, poultry and fish; lids; cups; bottles; guides and separators for handling and displaying the foregoing; trim pieces for packaging, storing and transporting electronics, mirrors, artwork and other fragile parts; buckets; tubing; industrial, automotive, marine, aerospace and military parts such as gaskets, spacers, seals, cushions and the like; and related dies, screen forms, formulations, processes, chemical formulations, tools, slurry dispensing, chemical monitoring, chemical injection, and related systems, devices, methods and techniques for making the foregoing.

[0023] A prior art production line for making molded fiber parts or products is described in Chinese Patent Application No. 201711129438.X, entitled "Flexible Production Line for Producing Pulp Molded Products" (hereinafter referred to as the "'438 Application"), the entire contents of which are hereby incorporated by reference. The '438 Application generally describes a forming station that includes a forming mold with a screen disposed on the forming mold. The forming mold produces a wet part by immersing a first mold in a trough of fiber slurry, extracting fibers through a vacuum channel in the mold until a desired amount of fibers are collected on the screen, and then removing the mold with the attached fiber layer from the slurry. In the system described in the '438 Application, the forming station also subjects the wet part to a forming operation in which the first mold with the attached fiber layer is pressed into a second mold after being removed from the slurry. This forming operation removes some moisture from the wet part and contours the surface of the wet part opposite the first mold. In the production line of the '438 application, after the molded fiber parts are manufactured in the molding station, they are then pressed in the pressing station. The pressing stations can be multiple pressing stations running in parallel. In one example of the '438 application, four pressing stations are used. Each of the four pressing stations in the '438 application includes a single pressing device. After pressing, the parts are sent to the stacking station. The molding station, pressing station and stacking station are arranged in a circle around a robot located in the center that controls an extendable robotic arm. The robot and the robotic arm are configured to remove the molded parts from the molding station and transfer them to any one of the four pressing stations. The robotic arm is also configured to remove the pressed parts from any one of the pressing stations and transfer them to other pressing stations or stacking stations. Although the application describes some basic components and stations of the molded fiber part manufacturing production line, it unfortunately exposes some inefficiencies.

[0024] The present application is directed to a new method for manufacturing a screen for use in conjunction with a forming die at a forming station. In an example, a flat plate of a woven wire mesh is gradually formed in stages using a set of punches and dies. Unlike single-stage forming, multi-stage forming allows forming to proceed from the center portion of the screen toward the periphery. This center-to-outward approach helps prevent wrinkles and minimizes the degree of deformation of the openings between the meshes because the screen can be gradually formed. To achieve this, a set of concentric punches or presses are sequentially advanced into the die system. Once the interior of the screen is deformed, the press maintains pressure on the interior of the screen while deforming the exterior, so that the previously deformed portion of the screen can be fixed while the rest of the screen is deforming. This operation of limiting the movement of the deformed portion of the interior of the screen while pressing the exterior portion of the screen allows the outer edge of the screen to be pulled inward, and as the outer portions of the screen are pressed and deformed, the mesh is prevented from being stretched, which may cause poor performance when the screen is installed on the forming die. First, the screen is placed over the die opening and secured with a press plate and a series of screws, bolts, or other fasteners. In other examples, the weight of the press plate may be sufficient to hold the screen in place. The screen is not held tightly between the die plate and the press plate; rather, the screen is held loosely so that deformation of the screen pulls the edges of the screen inward toward the center. The punches are nested and then pressed into the screen using a press (e.g., a hydraulic, pneumatic, or electric press), starting with the innermost punch and working outward. The resulting screen has little to no wrinkles, folds, or excessive weave deformation. Screens made in this way can be trimmed along the outer edges, or left flat so that they can be secured with the rings of a more common forming die.

[0025] In another example, the press applies pressure to multiple punches sequentially. Figure 3E As depicted, a rigid spring is provided, which in combination applies pressure to the innermost punch as the press applies force to the plunger which directly drives the middle punch. When the inner punch reaches maximum depth, the spring is compressed as the middle punch is forced downward by continued pressure on the plunger. Just before reaching maximum depth, the outer punch grabs the plunger to deform the screen along the perimeter. In this way, wrinkles and folds are reduced or eliminated, and the mesh does not close. Some slight ripples may be present along the perimeter area of ​​the screen, but this is outside the area used for forming.

[0026] In the example, screens were formed using 40 mesh and 60 mesh materials by the above method, and then placed one on top of the other and installed in a forming mold tool kit designed specifically for these screens. The tool includes a porous mold body that supports the screens while facilitating vacuum flow. The screens are placed on top of this body, first with 40 mesh and then with 60 mesh as the outermost layer. Subsequently, the tool is placed into the fiber slurry at the forming mold station and the slurry is collected. The tool is then placed into the fiber slurry at the forming mold station and the slurry is collected. The formed part does not have any major problems such as thin spots or tears, and can be cleanly removed from the mold. In addition, the degree of shape restoration is comparable to that of conventionally manufactured screens.

[0027] In another example, the nested punch unit is increased from three punches to four punches. The number of punches depends largely on the number of ridge features in the part. In the example coffee cup lid, four stages may be required, but for a flip-top container, fewer stages may be required. The outer edge of the die is dished-out, which helps collect more slurry. When combined with the rest of the tool, this creates a gripping skirt geometry that holds the part to the mating container. Sharp corners are also softened.

[0028] In the example nested punch unit, a set of three springs are designed into the punch stack, with the spring weight roughly doubling at each stage. Likewise, when downward force is applied (provided by the pressing device), the springs transfer that force to the screen. As the forming process progresses, each punch bottoms out and maintains pressure as the subsequent punch compresses the spring. The resulting screen is smoother, with almost no wrinkles along the perimeter, no signs of tearing, and even less force required to form (indicating lower stress on the screen). The screen is again installed into the quick-change die and lowered into the molded fiber slurry. This configuration accumulates more slurry along the skirt to better form the gripping skirt features at the hot press.

[0029] Figure 1A and Figure 1B A stereoscopic view and a partially enlarged stereoscopic view of a mold 100 used in a molding station are shown respectively. Figure 1A and Figure 1BThe forming mold 100 is formed from a machined unitary component 102. The unitary component 102 has a cavity mold 104 formed therein, and in the example shown, the cavity mold 104 includes an integral trimmer 106 that defines the outermost extent of a molded fiber product (not shown) formed using the mold 100. As described above, one or more vacuum channels formed in the component 102 can be communicatively coupled to ports 110 on the surface of the cavity 104 to extract liquid from the partially molded fiber component under vacuum during a pressing operation. Figure 1A and Figure 1B The mold 100 in the figure is intended to illustrate the complex mold shapes that may be formed in a production line, such as those shown in the '438 application. A screen must also be formed to cover the mold 100, and the screen is generally similar in contour to the mold 100 itself. During the molding process, the pulp slurry is sucked onto the screen under the action of a vacuum for the initial molding of the molded part. Complex molds may require equally complex screens, and the formation of any screen (especially complex screens) requires significant deformation of the originally flat screen to obtain a final shape factor suitable for use. Any type of deformation (especially complex deformations, or deformations required to manufacture particularly tall molded fiber parts) may damage the screen, resulting in gaps between the screen wires that are larger than acceptable, or causing wrinkles, creases, or other conditions that result in poor appearance of the molded fiber product, and these conditions may be affected by failure points.

[0030] Therefore, the technology described herein adopts a multi-stage or nested pressing unit to form a screen in multiple stages. The nested pressing unit containing multiple individually actuated pressing devices is used to form the screen in a segmented manner, rather than in a single pressing operation. In the example, the formation process of the completed screen is as follows: First, the innermost part of the screen is deformed with the first (innermost) part of the press unit. After that, the second part arranged on the outside of the first part of the screen is deformed with the second (middle) part of the pressing unit, and the second part of the pressing unit is positioned adjacent to the first part and surrounds the first part. Thereafter, the third part of the screen arranged on the outside of the second part is deformed with the third part (also referred to as the middle part) of the pressing unit, and the third part of the pressing unit is positioned adjacent to the second part and surrounds the second part. This multi-stage deformation operation continues until the outermost pressing device in the nested pressing unit (positioned adjacent to the last middle part of the pressing unit and surrounding the last middle part) deforms the outermost part of the screen. During each individual deformation process, pressure is maintained on the deformed portion of the screen by the corresponding pressing portion of the nested pressing unit. This helps to ensure that the screen material is pulled inwards from the free outer edges of the screen, rather than stretching the more centrally located portion of the screen.

[0031] The nested pressing unit can be formed by any number of independently actuated pressing devices. In the example, each independent pressing device can be actuated by applying pressure only to the independent pressing device. In other examples, each pressing device can be biased away from adjacent pressing devices by a spring or other biasing member. Each spring may have an elastic force, which is calculated as a compression provided according to the resistance provided at each stage of the screen deformation. In other words, in the nested pressing unit including a spring between two independent pressing devices, when the middle pressing device of the nested pressing unit deforms the screen, the spring can resist the deformation (that is, the elastic force of the spring is greater than the inherent elastic force of the screen material to resist deformation). Once the central part of the screen is completely deformed, the elastic force of the spring is calculated to be less than the inherent elastic force of the remaining screen material to deform again. These spring coefficients can be calculated according to the needs of any number of independent pressing devices in the nested pressing unit.

[0032] Figure 2A and Figure 2B An exploded perspective view and an exploded cross-sectional perspective view of a system 200 for deforming a screen are shown, respectively. Figure 2C A cross-sectional view of a nested punch unit 208 forming part of the system 200 is shown. Figure 2A , Figure 2B will with Figure 2C The system 200 includes a mold plate 202, the mold plate 202 including a contoured surface 202a and a center point disposed along an axis A. For illustrative purposes, Figure 2A and Figure 2B , the completed screen 204 is shown between the die plate 202 and the retainer plate 206, which defines an opening 206a and a retainer center point also arranged along the axis A. The nested punch unit 208 is configured to be accommodated in the opening 206a. The nested punch unit 208 includes a center punch or inner punch 208-1, an intermediate punch 208-2, and an outer punch 208-3. The outer punch 208-3 also includes a guide 208b that interacts with the opening 206a. The outer punch 208-3 also allows relative sliding of the punches 208-1 and 208-2. As described herein, the plunger 208a presses the center punch 208-1 and the intermediate punch 208-2 (the plunger 208a is integrally formed with them). As described herein, the spring 208 c disposed between the inner punch 208 - 1 and the middle punch 208 - 2 partially controls the actuation of the nested punch unit 208 .

[0033] In the example, when the plunger 208a is pressed, the elastic force of the spring 208c is greater than the inherent elastic force of the screen 204, which enables the screen 204 to be deformed downward and deformed between the inner punch 208-1 and the contour surface 202a of the die plate 202. As described in more detail herein, pressing the plunger 208a causes the spring 208c and the inner punch 208-1 to move forward together within the guide 208b until the inner punch 208-1 bottoms out (e.g., reaches the end of its range of motion), so that the screen 204 is tightly pressed between the contour surface 202a of the die plate 202 and the inner punch 208-1. At this stage, the plunger 208a moves further downward, causing the intermediate punch 208-2 to move forward as the spring 208c is compressed between the inner punch 208-1 and the intermediate punch 208-2. Thus, the middle punch 208-2 deforms the outer portion of the screen 204, while at the same time, the spring 208c also maintains a compressive force on the inner punch 208-1 and that portion of the screen 204. The plunger 208a and the middle punch 208-2 may move forward while deforming the portion of the screen 204 below them until the middle punch 208-2 bottoms out. Further deformation functions of the nested pressing unit will be Figure 2C is described in the context of .

[0034] Figure 2C A cross-sectional view of a nested punch unit 208 is shown, for example, Figure 2A and Figure 2B As shown. Each of the inner punch 208-1, the middle punch 208-2, and the outer punch 208-3 includes a pressing profile 210-1, 210-2, 210-3, respectively. Each pressing profile 210-1, 201-2, 210-3 can be substantially similar to a related portion of the contour surface 202a of the die plate 202, for example, the contour surface 202a (such as Figure 2A and 2B As shown in Figure 2CAs shown, as described above, pressing the plunger 208a downward moves the inner punch 208-1 forward together with the spring 208c and the intermediate punch 208-2 integral with the plunger 208a. Once the inner punch 208-1 hits the bottom, further downward movement of the plunger 208a compresses the spring 208b to maintain pressure on the portion of the screen that is deformed by the inner punch 208-1, while the pressing profile 210-2 of the intermediate punch 208-2 deforms the screen. Continued pressing of the plunger 208a causes the shoulder 212 of the outer punch 208-3 to contact the flange 214 of the plunger 208a to move the outer punch 208-3 forward. In this example configuration, the outer punch 208-3 performs a crimping function. Once the punches 208 - 1 , 208 - 2 , 208 - 3 bottom out, deformation is terminated and the completed screen can be removed for further processing, such as trimming.

[0035] Figure 3A-3H An example system 300 for deforming a screen 302 and a method of deforming a screen 302 are shown. The figures will be described together, and not all features must be depicted or labeled in all figures. The system 300 includes a mold plate 304 that includes a contoured surface 306 and a plurality of mating receivers 307 around the perimeter of the contoured surface 306. The contoured surface 306 approximates the shape of both the mold to which the finished deformed screen is to be mounted and the finished molded fiber part. Figure 3B As shown, the screen 302 is placed on the mold plate 304 to cover the contour surface 306 of the mold plate 304. In this position, the screen 302 actually defines a flat reference plane above the contour surface 306. Figure 3C , a retainer plate 308 is disposed on top of the screen 302. The retainer plate 308 may be secured to the mold plate 304 by a plurality of mechanical fasteners (e.g., bolts or screws, not shown) that are inserted into a plurality of fastener openings 310 to extend into mating receiving portions 307 of the mold plate 304. The retainer plate 308 defines an opening 312 that may include a center point centered on the contoured surface 306 disposed along the axis A.

[0036] exist Figure 3D In the embodiment, a nested punch unit 314 is provided. In this example, the nested punch unit 314 is structurally similar to Figure 2A-2C The guide 316 of the nested punch unit 314 is inserted into the opening 312 and at least lightly placed on the screen 302 while being supported by the die plate 304, such as Figure 3E In this figure, the screen 302 still maintains its initial planar shape before being subjected to any deformation. Figure 3F The first stage of the pressing operation is shown, in which the plunger 318 of the nested punch unit 314 is shown pressed against the die plate 304. The spring 320 provides a greater elastic force than the inherent elastic force of the screen 302 during deformation, so when the plunger 318 is pressed down, the inner punch 322 is kept pressed down. This causes the screen 302 to deform between the die plate contour 306 and the pressing contour 324 of the inner punch 322; once the inner punch 322 bottoms out, the deformation of the screen 302 between the inner punch 322 and the die plate contour 306 is complete. Figure 3F Also shown is a portion 302a of the screen 302 that is not deflected downwardly into the die plate 304 below the inner punch 322, but which has not yet been formed because it has not yet been deformed by any corresponding part punch or profile. Thus, this portion 302a generally corresponds to that portion of the screen that is pulled inwardly from its outer edge when the interior of the screen 302 is pressed and formed. Figure 3F 'yes Figure 3F FIG. 1 is an enlarged partial view of the system, more clearly depicting the complex die plate contour 306 and the corresponding pressing contour 324 of the inner punch 322 . Figure 3F Also shown is the pressing profile 326 of the intermediate punch 328, and the portion 302a of the screen 302 that is pulled into the die plate 304 before the actual pressing and forming of the profile.

[0037] Figure 3G The completion of the second stage of deformation of the screen 302 is shown, with the middle punch 328 bottoming out at the contour 306 of the die plate 304. In this case, the spring 320 is also fully compressed so that when the inner punch 322 presses the screen 302, the portion 302a of the screen 302 that has been pulled down into the die plate 304 is pressed and formed. Figure 3G Also shown is the situation where the plunger 318 contacts the outer punch 329 so as to force the outer pressing profile 331 into the screen 302 to curl the screen 302. Figure 3H , the nested punch unit and the retainer plate have been removed from the system 300. The deformed screen 302 is removed from the mold plate and may have a peripheral portion 330 that may be trimmed or removed from around the completed deformed screen 332. It can be seen that because the edges of the screen 302 are not tightly held between the retainer plate 308 and the mold plate 304, the completed deformed screen 332 includes an inwardly pulled edge 334, wherein the screen 302 is pulled inwardly during the deformation process without undesirable stretching of the mesh. The completed deformed screen 322 can then be attached to an associated mold for forming a molded fiber part.

[0038] Figure 4A-4EAnother example system 400 for deforming a screen 402 and a method of deforming a screen is shown. Figures 3A-3H As in the example of , the system 400 includes a die plate 404 with a die plate profile 406. A retainer plate 408 is secured to the die plate 404 by fasteners inserted through openings 407, 410 and includes a guide 416 integral therewith. The nested punch unit 414 includes an inner punch P1, a second (middle) punch P2, a third (middle) punch P3, and an outer punch P4 integral with a plunger 418. Each of the punches P1-P4 is biased away from an adjacent punch by a spring S1, S2, S3. When the plunger 418 is depressed, the spring force of each spring S1, S2, S3 causes the force to bias adjacent punches P1, P2, P3, P4 away from each other until the punch associated with a particular spring S1, S2, S3 bottoms out (respectively) at the profile 406 of the die plate 404. For example, in Figure 4A In FIG. 4 , before the plunger 418 is depressed, all springs S1, S2, S3 bias the punches P1, P2, P3 away from the punch P4. Figure 4B In the embodiment of the present invention, the punch P1 has almost bottomed out, executing the first stage of deformation of the screen 402, but the spring S1 has not yet been compressed. This causes the portion 302a of the screen 302 adjacent to the screen 302 disposed between the punch P1 and the die plate 304 to be pulled in.

[0039] exist Figure 4C , punch P1 has bottomed out. As punch P2 moves downward, the further downward force on plunger 418 compresses spring S1 until spring S1 is fully compressed and punch P2 bottoms out. As punch P3 moves downward, the further downward force on plunger 418 compresses spring S2. Figure 4D In the embodiment, the punch P3 has bottomed out, thereby fully compressing the spring S2. When the punch P4 moves downward, the further downward force on the plunger 418 compresses the spring S3. Figure 4E In the embodiment of the present invention, the punch P4 has bottomed out, thereby fully compressing the spring S3. As each punch P1, P2, P3, P4 sequentially deforms the relevant portion of the screen 402, the punch P1, P2, P3, P4 that has previously bottomed out maintains pressure on the screen 402 on those portions that have already been deformed, thereby preventing the deformed portions from being pulled outward from the center of the screen 402. Instead, the outer portions of the screen 302 are pulled further inward until the entire compression operation is completed.

[0040] Figure 5A method 500 of forming a forming die screen is shown. The method 500 begins at operation 502, where a substantially flat screen is positioned between a die plate and a retainer plate. Examples of such a die and retainer plate are described herein. However, in general, the die plate will include a profile and the retainer plate will define an opening having a retainer plate center point substantially aligned with a center point of the profile. In operation 504, sequentially deforming the screen is performed with a plurality of punches. In an example, the sequentially deforming includes sequentially deforming the screen with a plurality of punches that are substantially centered along an axis aligned with the center point of the profile. As shown in FIG. Figure 5 As shown, operation 504 includes multiple sub-operations depending on the number of punches. In an example, the multiple punches include an inner punch and an outer punch, and the inner punch and the outer punch are actuated sequentially so that the inner punch deforms the screen first, operation 506. Depending on the configuration of the deformation system, the pressure applied by the inner punch on the screen is at least partially applied by a first spring, which can bias the inner punch away from an adjacent punch (if used, the adjacent punch can be an outer punch or an intermediate punch).

[0041] Figure 5 Method 500 contemplates the use of an optional intermediate punch when forming a screen. Whether one or more intermediate punches are used, or an outer punch is used, when any adjacent punch is used to deform the screen, operation 508 is performed to apply pressure to the screen with the inner punch. In operation 510, deformation of the screen is performed using the intermediate punch. The pressure applied by the intermediate punch on the screen can be at least partially applied by a second spring, which can bias the intermediate punch away from an adjacent punch (e.g., an outer punch). The dashed box 512 indicates that operations 508 and 510 are performed simultaneously. As described above, this prevents the already deformed screen mesh material from being pulled outward when the exterior of the screen is pressed and deformed. Once the screen is fully deformed by the intermediate punch, both the inner punch and the intermediate punch apply pressure to the screen, operation 514. The screen is then deformed by the outer punch (operation 516), and operation 516 is performed substantially simultaneously with operation 514 (as shown in dashed box 518). Therefore, in Figure 5 In the method shown, the outer punch finally deforms the screen after the inner punch and then the intermediate punch have deformed the screen in sequence. Any number of intermediate punches may be included to sequentially deform the screen, depending on the requirements or desires of a particular application.

[0042] Figure 6Another method 600 for forming a forming die screen is shown. The method 600 begins at operation 602, where a die plate defining a plate contour and a die center point is provided. Examples of such a die plate are shown and described herein. At operation 604, a screen is placed on the die plate. The screen is oversized relative to the area of ​​the die plate contour so as to provide sufficient material to fully deform during the processing described herein. In its initial configuration, before any deformation process has been performed, the screen substantially defines a plane. The method continues at operation 606, where a retainer plate is secured to the die plate. Examples of such a retainer plate are described herein; in the examples, the retainer plate defines an opening having a retainer center point substantially aligned with the die center point. Once the retainer plate is placed, the screen is between the die plate and the retainer plate. At this point, the retainer plate is secured to the die plate as described herein. At operation 608, a nested punch unit is inserted into the opening. A variety of different configurations of nested punch units are described herein, which will be apparent to those skilled in the art. In one example, the nested punch unit includes at least an inner punch and an outer punch arranged around the inner punch. It may also include one or more intermediate punches located between the inner punch and the outer punch. No matter how many punches are used, the punches can be aligned along an axis that is substantially aligned with the center point of the retainer plate.

[0043] In operation 610, pressing the screen with the nested punch unit is performed. In an example, this operation includes pressing the screen with the inner punch and then pressing the screen with the outer punch, which allows the screen to deform and the edges of the screen to be pulled inward into the die plate without significant separation or stretching of the mesh. Fig. 6A Further operations related to operation 610 are described in the context of Figure 6 Description, once pressing operation 610 is completed, just carry out operation 612, promptly take out the screen from between retainer plate and mold plate.After this, can trim the edge of screen, operation 614.

[0044] Fig. 6A Shown with Figure 6 Optional operations related to method 600. That is, Fig. 6A As shown in the above Figure 6Optional operations that can be performed during the pressing operation 610 in . One or more of these optional operations can be performed as part of the pressing operation 610. For example, operation 620 considers moving the inner punch toward the plate contour while substantially maintaining the position of the outer punch relative to the plate contour. In operation 622, the inner part of the screen is deformed with the inner punch. After such an operation, operation 624 can be performed, in which the inner punch is bottomed against the screen and the die plate before the outer punch is used to press the screen. In the example, pressing the screen with the nested punch unit can also include operation 626, in which the inner punch is used to maintain pressure on the screen while the outer punch is used to deform the screen. Operations 624 and 626 help prevent further deformation of the pressed, deformed portion of the screen during any subsequent pressing operation of the pressing position around the inner punch. In a nested punch including an intermediate punch, operation 628 can be performed after operation 622; that is, the screen is pressed with at least one intermediate punch. The bottoming out and holding pressure operations described in the context of the inner punch may also be performed by any number of intermediate punches included in the nested punch. Any number of intermediate punches may be used as needed to perform the deformation operation until operation 630, when the screen is pressed with at least one outer punch. The outer punch may also be used to perform the deformation and bottoming operations. Any number of intermediate punches may be used as needed to perform the deformation operation until operation 630, when the screen is pressed with at least one outer punch. The outer punch may also be used to perform the deformation and bottoming operations.

[0045] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the technology are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0046] It will be apparent that the systems and methods described herein are well suited for achieving the purposes and advantages set forth above, as well as those inherent to the systems and methods themselves. Those skilled in the art will recognize that the methods and systems of this specification may be implemented in a variety of ways and are therefore not limited by the exemplary embodiments and examples described above. In this regard, any number of features of the various embodiments described herein may be combined into a single embodiment, and alternative embodiments having fewer or more than all of the features described herein are possible.

[0047] Although various embodiments have been described for the purpose of the present disclosure, various changes and modifications may be made, which are fully within the intended scope of the present disclosure. Many other changes that are easily conceivable to those skilled in the art may also be made, and these changes are included in the spirit of the present disclosure.

Claims

1. A method for forming a forming mold screen, the method comprising: providing a mold plate defining a plate contour and a mold center point; placing a screen on the mold plate; securing a retainer plate to the mold plate, wherein the retainer plate defines an opening having a retainer center point substantially aligned with the mold center point, and wherein the screen is disposed between the mold plate and the retainer plate and the screen substantially defines a plane; inserting a nested punch unit into the opening, wherein the nested punch unit includes an inner punch and an outer punch disposed around the inner punch, and wherein the inner punch and the outer punch are aligned along an axis that is substantially aligned with a center point of the retainer; and The mesh is pressed with the nested punch unit, wherein pressing the mesh with the nested punch unit includes: pressing the mesh with the inner punch and then pressing the mesh with the outer punch.

2. The method according to claim 1, wherein: The nested punch unit includes at least one intermediate punch arranged between the inner punch and the outer punch, and wherein, pressing the screen with the nested punch unit includes: pressing the screen with the at least one intermediate punch after pressing the screen with the inner punch and before pressing the screen with the outer punch.

3. The method according to claim 1, wherein: Pressing the screen with the nested punch unit includes moving the inner punch toward the plate contour while substantially maintaining the position of the outer punch relative to the plate contour.

4. The method according to claim 1, wherein: Pressing the screen with the nested punch unit includes deforming an interior of the screen with the inner punch.

5. The method according to claim 4, wherein: Pressing the mesh with the nested punch unit includes maintaining pressure on the mesh with the inner punch while deforming the mesh with the outer punch.

6. The method according to claim 1, wherein: Pressing the screen with the nested punch unit includes bottoming the inner punch against the screen and the die plate before pressing the screen with the outer punch.

7. The method according to claim 6, wherein: Bottoming the inner punch substantially prevents the inner punch from further deforming the screen.

8. The method according to claim 1, wherein: The nested punch unit includes a pressing profile that is substantially similar to the plate profile.

9. The method according to claim 6, wherein: Pressing the screen with the nested punch unit includes bottoming the outer punch against the screen and the die plate.

10. The method according to claim 9, further comprising: removing the screen from between the retainer plate and the mold plate; as well as The screen is trimmed.

11. A method of deforming a substantially flat screen, the method comprising: disposing the substantially flat screen between a mold plate including a contour and a retainer plate defining an opening, the opening having a retainer center point substantially aligned with a center point of the contour; as well as The screen is deformed sequentially using a plurality of punches, wherein the plurality of punches are substantially centered along an axis aligned with a center point of the profile, and wherein the plurality of punches include inner punches and outer punches, and wherein the inner punches deform the screen first, and wherein the outer punches deform the screen last.

12. The method according to claim 11, further comprising: During the process of the outer punch deforming the screen, pressure is applied to the screen by the inner punch.

13. The method according to claim 12, wherein: The pressure exerted by the inner punch on the screen is at least partially exerted by a first spring.

14. The method according to claim 13, wherein: The first spring biases the inner punch away from the outer punch.

15. The method according to claim 14, wherein: The plurality of punches further includes an intermediate punch between the inner punch and the outer punch, and wherein the intermediate punch deforms the screen after the inner punch and before the outer punch.

16. The method according to claim 15, further comprising: During the process of the outer punch deforming the screen, the middle punch is used to apply pressure to the screen.

17. The method according to claim 16, wherein: The pressure exerted by the intermediate punch on the screen is at least partially exerted by a second spring.

18. The method according to claim 17, wherein: The second spring biases the intermediate punch away from the outer punches.

19. A system for deforming a screen, the system comprising: a mold plate, which defines the contour and the mold center point; a retainer plate defining an opening having a retainer center point substantially aligned with the mold center point; as well as A nested punch unit comprising an inner punch, an outer punch disposed about the inner punch, and a first spring biasing the inner punch away from the outer punch, wherein the inner punch and the outer punch are aligned along an axis substantially aligned with a center point of the retainer, wherein the nested punch unit comprises a deformed surface substantially mirroring the profile.

20. The system of claim 19, wherein: The inner punch is at least partially slidably engaged with the outer punch.

21. The system of claim 19, wherein: The nested punch unit also includes: at least one intermediate punch disposed between the inner punch and the outer punch; and A second spring biases the intermediate punch away from the outer punch, and wherein the first spring biases the inner punch away from the intermediate punch.

22. The system of claim 21, wherein: The inner punch is at least partially slidably received by the intermediate punch, and the intermediate punch is at least partially slidably received in the outer punch.

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