Tool or tool part used in a process for molding a product from a pulp slurry

Abstract

This document discloses a tool or tool part (10, 20, 30, 40) for use in a process of molding products from a slurry. The tool or tool part (10, 20, 30, 40) includes a self-supporting tool wall portion having a product face (Fp) for contacting the product and a back face (Fb) on the opposite side of the wall relative to the product face (Fp). The tool wall portion presents a perforation provided by a plurality of channels (102) extending through the tool wall portion from the product face (Fp) to the back face (Fb). The channels (102) are straight or curved, having no more than one inflection point.

Description

[0001] This application is a divisional application of two other applications: one filed on December 22, 2014, with application number 201480084293.4, entitled "Tool or Tool Part, System Including Such Tool or Tool Part, Method of Producing Such Tool or Tool Part, and Method of Molding Products from Slurry"; and the other filed on December 22, 2014, with application number 2019113528348, entitled "Tool or Tool Part Used in a Process of Molding Products from Slurry". Technical Field

[0002] This disclosure relates to tools or tool parts for molding products from slurry. This disclosure also relates to methods of producing such tools and various uses of such tools or tool parts. Background Technology

[0003] Products are known to be molded from pulp by immersing a porous mold in a pulp and then drying and optionally pressing the molded product. Examples of such products are egg cartons, shock-absorbing packaging inserts and paper trays, paper cups, beverage trays, mushroom and berry boxes, and other forms of industrial, agricultural, and consumer packaging.

[0004] Porous slurry molding dies are made from woven wire cloth material, which is stretched to conform to the die surface. This type of die has some drawbacks in terms of the amount of twist or stretch that allows the woven wire cloth material to conform to the die surface. Other drawbacks include the wire cloth's tendency to tear. Using wire cloth also involves some limitations on the complexity of the products that can be molded. In particular, when the wire cloth is formed into the die, the holes in the cloth deform, making it impossible to control the distribution of the openings.

[0005] Another drawback is the cost of manufacturing such molds: since the fabric is usually not self-supporting, a metal backing specifically for the product being molded is required. Furthermore, these tools are prone to clogging and difficult to repair.

[0006] It is also known, for example, from US3067470, to provide porous slurry molds from small spheres that are sintered together to provide a porous body. This body can be made from polymeric materials as disclosed in US3067470. However, this type of mold has disadvantages not only in terms of the strength and limited temperature range over which they can be used, but also in the trade-off between surface quality and pressure drop: the finer the particles used at the surface, the smaller the channels, and therefore the greater the pressure drop.

[0007] WO2011059391A1 discloses a method for making slip molds by sintering particles of a metallic material such as bronze together. Although this type of mold can withstand higher temperatures compared to polymer-based molds, its manufacture involves a more difficult sintering process due to the need for higher temperatures. Furthermore, the finished mold possesses the same characteristics as molds made from polymer materials.

[0008] Therefore, several challenges remain regarding products manufactured from pulp molding: the desire to provide smoother surface textures to reduce energy consumption, to offer cheaper processes for mold making, and to provide durable molds that can withstand high temperatures. Improved quality control of the molding process is also desired. Summary of the Invention

[0009] The purpose of this disclosure is to provide an improved mold for molding products from slurry.

[0010] The present invention is defined by the appended independent claims, and embodiments are set forth in the appended dependent claims in the following description and drawings.

[0011] According to a first aspect, a tool or tool part is provided for use in a process of molding products from a slurry. The tool or tool part includes a self-supporting tool wall portion having a product face for contacting the product and a back face on the opposite side of the wall relative to the product face. The tool wall portion presents apertures provided by a plurality of channels extending through the tool wall portion from the product face to the back face. The channels are straight or curved, having no more than one inflection point.

[0012] For the purposes of this disclosure, the term "slurry" should be interpreted to include materials comprising fibers (e.g., cellulose, minerals, and starch) and combinations thereof. The slurry preferably has a liquid carrier, which may contain water.

[0013] The term "self-supporting" refers to a tool wall section that has sufficient rigidity and a sufficiently high melting point for the tool wall section, without requiring any support structure to maintain its shape during operation.

[0014] The product surface can be the molding surface in a slurry pick-up tool, the contact surface in a transfer tool, or the molding surface in a male or female pressing tool.

[0015] A curved channel can be curved in one or more planes.

[0016] The tools or tool parts conceived according to the present invention can provide efficient pickup, transfer or evaporation of slurries or molded products, while requiring less energy to generate a vacuum compared to the prior art.

[0017] Tools or tool parts may have a product surface, which may present a flat surface portion or a convex surface portion.

[0018] A convex surface portion can be convex in one or two mutually perpendicular planes.

[0019] The tool wall thickness at the convex surface portion can be smaller than that at the flat surface portion, preferably 30%-70% or 40%-60% smaller.

[0020] A convex surface portion can have a greater porosity than a flat surface portion.

[0021] Therefore, a vacuum is provided when needed.

[0022] The surface of a product can have both flat and concave sections.

[0023] A planar surface portion can exhibit greater porosity than a concave surface portion.

[0024] A concave surface portion can be concave in one or two mutually perpendicular planes.

[0025] The product surface may have a pair of surface portions that are generally planar and present an angle of 45° to 135° relative to each other, wherein the surface portion presenting the largest angle relative to the horizontal plane during the main operation of the tool or tool part has a greater porosity than the other surface portions.

[0026] "The main operation of the tool" is understood as a part of the tool's operation, during which it performs its primary function relative to the product to be molded. Therefore, for a pick-up tool, the primary function will be performed when the slurry is picked up by means of an applied vacuum. For a transfer tool, the primary operation will be performed when the slurry is transferred from the pick-up tool to the transfer tool. For a pressing tool, the primary operation will be the pressing operation.

[0027] At least some channels can present a channel opening area on the product surface, where the channel opening area is smaller than the corresponding channel opening area on the back side.

[0028] Therefore, the risk of congestion is reduced.

[0029] At least some of the channels can present a cross-section that tapers toward the product surface.

[0030] At least some of the channels may present a central axis that extends at an angle of 40-90 degrees relative to the product surface.

[0031] At least some of the channels may exhibit a curved central axis.

[0032] The product surface may present a first juxtaposed surface portion and a second juxtaposed surface portion, and the central axis of the channel opening at the first surface portion may extend at different angles relative to the product surface of the surface portion where they open, compared to the central axis of the channel opening at the second surface portion.

[0033] The void volume within a tool or tool part can be at least 20%, preferably at least 40%, at least 60%, or at least 80% of the total volume spanned by the tool or tool part.

[0034] Void volume is the volume formed by voids (i.e., not the volume of heaters, support bodies, etc.).

[0035] Therefore, enhanced vacuum distribution on the product surface is achieved, thereby reducing the demand for vacuum power.

[0036] At least some of the channels can have a length exceeding the wall thickness near the channel.

[0037] At least some of the product face openings in the channel can have a cross-section with a maximum width of 0.1-2 mm.

[0038] At least some of the channels may have at least one branch located between the product front and back.

[0039] The thickness of the tool wall is 0.2-20mm, preferably 0.3-15mm or 0.5mm-10mm.

[0040] The tool wall portion can be formed as a homogeneous material part, and the gap between the channels is less than 95%, preferably less than 99% or less than 99.9%.

[0041] Tools or tool parts may be formed from materials and have a wall thickness sufficient to enable the tool or tool part to be self-supporting during operation.

[0042] The back of the tool may be exposed to a chamber, preferably at least 70% or at least 90%, which is adapted to provide an air pressure different from the ambient pressure.

[0043] Tools or tool parts may form part of a tool selected from the following groups:

[0044] Pick-up tools are used to pick up slurry from a paste-like material.

[0045] A transfer tool used to receive a certain amount of slurry from another tool, and

[0046] A pressing tool used to press a certain amount of slurry to form a molded product.

[0047] The tool or tool part may include at least two tool wall portions that are interconnected, preferably movably interconnected.

[0048] According to a second aspect, a system for molding products from a slurry is provided, the system comprising at least one tool or tool part as described above, means for applying the slurry to the surface of the product, and means for drawing a vacuum and / or applying a pressure greater than the ambient air pressure from behind.

[0049] The system may also include a heating element disposed on the rear side of the tool wall portion and adapted to supply heat to the tool wall portion.

[0050] The heating element can be arranged in the heater section, which is spaced apart from the tool wall section.

[0051] The heater section can be integrally formed with the tool wall section.

[0052] The heater section can be formed from a separate part and contacts the tool wall section via at least one spacer element.

[0053] This separate component can be formed from a material different from that of the tool wall portion. The spacer element can be integrally formed with the tool wall portion or the heater portion. Preferably, the spacer element is positioned so as not to obstruct any passage. This can be facilitated by forming the spacer element on the rear of the tool wall portion.

[0054] Alternatively, the heating element can be integrated with the tool wall.

[0055] For example, the heating element can be recessed into the rear of the tool wall portion.

[0056] According to a third aspect, a method is provided for producing a tool or tool part for molding a product from a slurry, the method comprising providing material particles from which the tool or tool part is to be formed, layers of a plurality of said particles being continuously distributed at a target surface, and directing an energy source to a location corresponding to a cross-section of each distributed particle layer at the target surface in which the tool or tool part is to be produced, such that the powder particles are fused together.

[0057] The method may also include forming a tool wall portion having pores provided by a plurality of channels extending through the tool wall portion from the product side to the back side, wherein the channels are straight or curved and have no more than one inflection point.

[0058] According to a fourth aspect, a method for molding a product from a slurry is provided, the method comprising providing a mold as described above, applying a vacuum to the rear of the mold, and applying the slurry to the product face of the mold.

[0059] The method may also include using a mold to pick up the slurry from the slurry container.

[0060] The method may also include using a mold to press the slurry to form a product, thereby removing at least some of the solvent from the slurry. Attached Figure Description

[0061] Figures 1a-1d The process of forming a product from a slurry is illustrated schematically.

[0062] Figures 2a-2e The mold wall sections with different channel designs are schematically shown.

[0063] Figure 3 A portion of the mold wall is shown schematically.

[0064] Figure 4 A portion of the pressing mold according to the first embodiment is shown schematically.

[0065] Figure 5 A portion of the pressing mold according to the second embodiment is shown schematically.

[0066] Figure 6 A portion of the pressing mold according to the third embodiment is shown schematically. Detailed Implementation

[0067] Figure 1a A pickup tool 10 is schematically shown partially submerged in a container 1 holding the slurry 2. The pickup tool is mounted to a tool holder 11, which, together with the pickup tool, defines a vacuum chamber 12 connected to a pressure regulator P1. The pressure regulator may have the capability to selectively generate at least a partial vacuum (i.e., an air pressure below ambient air pressure) and / or an air pressure above ambient air pressure.

[0068] When the pickup tool is immersed in the slurry 2, the pressure regulator P1 can generate a vacuum, causing the slurry fibers 3 to adhere to the product surface of the pickup tool 10.

[0069] Figure 1b A pick-up tool 10 is schematically shown for transferring slurry fibers 3 to a transfer tool 20. The transfer tool can be connected to a second pressure regulator P2, which is capable of generating vacuum or air pressure. The transfer tool can also be mounted on a transfer tool holder 21 to define a vacuum chamber 22, which is connected to the second pressure regulator.

[0070] During the transfer of the slurry fiber 3 from the pick-up tool to the transfer tool, an air pressure greater than the ambient pressure can be generated by the first pressure regulator P1 to release the slurry fiber from the pick-up tool.

[0071] Alternatively, or as a supplement, a vacuum can be generated by a second pressure regulator P2, allowing the slurry fibers to be received by the transfer tool 20.

[0072] Figure 1c A drying apparatus is schematically shown, comprising a heat generator 5 and an energy supply E. This drying apparatus can be used to remove a sufficient amount of water from the slurry 3 to adjust it for further processing and / or to complete the formation of product 3'.

[0073] Figure 1d A pressing device is schematically shown, comprising a male pressing tool 30 and a female pressing tool 40. One or both pressing tools may be mounted on corresponding tool holders 31, 41 and connected to corresponding vacuum chambers 32, 42. The vacuum chambers may be connected to corresponding pressure regulators P3, P4.

[0074] One or two of the pressing tools may be equipped with heating elements 33, 43, which are powered by energy suppliers E1, E2 and optionally controlled by controller C. Heating can be achieved by electric heating elements, hot air or liquid, or induction.

[0075] The pressing tool and its associated tool holder are movable relative to each other between an open position and a pressing position. In the open position, a partially molded slurry product can be inserted. In the pressing position, the pressing tools apply pressure toward each other, thereby pressing the product 3 between the product faces of the respective tools 30, 40.

[0076] When in the suppressed position, heat can be supplied by one or both of heaters 33 and 43.

[0077] During the pressing step, one or two pressure regulators P3, P4 can provide a vacuum to assist in the removal of water vapor from product 3”.

[0078] As an alternative, one of the pressure regulators can provide a vacuum, while the other provides a pressure greater than the ambient air pressure.

[0079] Optionally, hot air or steam can be introduced through the mold during the pressing process. Figure 1d ).

[0080] It should be noted that two or more consecutive pressing steps may be used, for example, to gradually form all or part of the product 3”, and / or to apply additional features (e.g., coatings, decorations, etc.) to the product.

[0081] In one implementation scheme, based on existing information... Figure 1a , Figure 1b as well as Figure 1d The described execution steps.

[0082] In one embodiment, the pick-up tool 10 can directly transfer the slurry fibers to the drying device. This transfer can be assisted by a first pressure regulator P1, which generates an air pressure greater than the ambient air pressure. Therefore, in this embodiment, only based on what has already been said about Figure 1a and Figure 1c The described execution steps.

[0083] In another embodiment, the picking tool 10 can also be used as a pressing tool. Therefore, in this embodiment, only based on what has already been said about... Figure 1a and Figure 1d The described execution steps.

[0084] Figures 2a-2e The diagram schematically illustrates mold wall sections with different channel designs. Each mold wall has a product face (Fp) and a back face (Fb). The product face is the side of the mold that contacts the product, and the back face is the opposite side of the mold wall. The back face typically defines a portion of the vacuum chamber.

[0085] The thickness of the mold wall can range from 0.25 mm to 10 mm, preferably from 0.5 mm to 5 mm. The wall thickness can vary between different parts of the tool. Furthermore, tools with different functions can have different thicknesses.

[0086] The channel connects the product side to the back side Fb. The opening area of ​​the channel on the product side can, but does not need to, be smaller than the opening area of ​​the channel on the back side. Therefore, the channel can have a cross-sectional area that decreases from the back side towards the product side.

[0087] The channel presents a central axis, which can be defined as a line or curve extending through the centroid of each channel cross-section taken parallel to the product surface Fp.

[0088] Figure 2a The wall portion of a slurry mold having a pair of channels of the same size and configuration is schematically shown. The channels present a corresponding first channel portion with a constant channel cross-section and a corresponding second channel portion with a tapered cross-section.

[0089] Figure 2b The diagram schematically shows a wall portion of a slurry mold with a pair of channels that taper continuously from the rear toward the product surface Fp.

[0090] Figure 2a and Figure 2bThe channels and their respective central axes extend perpendicularly to the product surface Fp.

[0091] Figure 2c The diagram schematically illustrates a portion of the mold wall containing a slurry, the central axis of which extends relative to the product surface Fp at an angle other than a right angle. This angle can be in the range of 20-90 degrees, preferably 30-90 degrees or 60-90 degrees.

[0092] Figure 2c The channel can have a constant cross-sectional area or a cross-sectional area that decreases toward the product surface Fp.

[0093] The wall portion of the mold can present channels extending at different angles within the interval.

[0094] Figure 2d The diagram schematically illustrates a wall portion of a slurry mold with curved channels. Specifically, these curved channels can be curved in one plane, as shown, or in two orthogonal planes.

[0095] Figure 2d The channel can have a constant cross-sectional area or a cross-sectional area that decreases toward the product surface Fp.

[0096] Figure 2e The diagram schematically illustrates a wall portion of a slurry mold with a curved channel having an inflection point. Specifically, this curved channel can be curved in one plane, as shown, or in two orthogonal planes.

[0097] Figure 2e The channel can have a constant cross-sectional area or a cross-sectional area that decreases toward the product surface Fp.

[0098] It should be noted that a mold can be presented according to Figures 2a-2e One or more channels are formed. Specifically, the mold may include at least one wall portion and another wall portion, the at least one wall portion comprising, according to... Figures 2a-2e Any one of the formed channels, the other wall portion includes according to Figures 2a-2e Another channel formed in the middle.

[0099] refer to Figure 2d and Figure 2e The bending radius of the channel can be greater than 1 / 2 of the wall thickness at the channel, preferably greater than 3 / 4 of the wall thickness or greater than 1 / 1 of the channel wall thickness.

[0100] It should be noted that the channel may present a cross-section that varies along the length of the channel. The channel may present at least a portion having a circular, elliptical, or polygonal cross-section (e.g., square, triangle, pentagon, hexagon, heptagon, octagon, nonagon, decagon, uneconoid, dodecagon), or other polygons having interior angles from 60° to 180°.

[0101] Figure 3 A portion of the mold wall is schematically shown, with the product facing up / to the right and the back facing down / to the left.

[0102] Figure 3 The mold wall portion can present a horizontal mold wall portion Ph during the main operating phase of the mold, i.e., a horizontal mold wall portion at + / - 45°, preferably at + / - 30° or + / - 15°. This horizontal mold wall portion can be planar or substantially planar. For example, such a substantially planar mold wall portion can be curved so that it deviates from the plane by less than 10%, preferably less than 5%, in any direction along the plane.

[0103] The mold wall can also be a convex mold wall portion Pcx, that is, a mold wall portion with a convex product surface Fp.

[0104] It should be noted that the convex mold wall portion can be convex in one or two mutually orthogonal directions.

[0105] The mold wall portion can also be a vertical mold wall portion Pv during the main operating phase of the mold, i.e., a vertical mold wall portion at + / - 45°, preferably + / - 30° or + / - 15°. This vertical mold wall portion can be planar or substantially planar. For example, a substantially planar mold wall portion can be curved so that it deviates from the plane by less than 10%, preferably less than 5%, in any direction along the plane.

[0106] The mold wall portion can also be a concave mold wall portion Pcv, that is, a mold wall portion with a concave product surface Fp.

[0107] For the purposes of this disclosure, the term "porosity" is defined as the ratio of the channel opening area of ​​a predetermined wall portion to the total wall area (including the channel openings).

[0108] The aperture openings on the product side can have a main diameter of 0.25 mm to 2 mm. The aperture openings on the back side can have a main diameter of 0.3 mm to 4 mm.

[0109] Therefore, the opening area of ​​the pore at Fp on the product surface is 0.045-3.2 mm. 2Preferably, it is 0.045-2mm. 2 or 0.050-1mm 2 .

[0110] Therefore, the opening area of ​​the pore at Fb on the back side is 0.45-13 mm. 2 Preferably 0.1-5mm 2 or 0.3-2mm 2 .

[0111] Therefore, the ratio of the back opening area to the product front opening area can be approximately 1.1 to 6, preferably 1.2 to 5 or 1.4 to 4.

[0112] The convex mold wall portion Pcx can exhibit the highest porosity among all mold wall portions. Preferably, the convex mold wall portion can have a porosity of 10% to 90%, more preferably 20% to 60%.

[0113] The vertical mold wall portion Pv can exhibit a lower porosity than the convex mold wall portion Pcx. Preferably, the vertical mold wall portion can have a porosity of 15% to 80%, more preferably 25% to 60%.

[0114] The horizontal mold wall portion Ph can exhibit a lower porosity than the vertical mold wall portion Pv. Preferably, the horizontal mold wall portion Ph can have a porosity of 20% to 75%, more preferably 30% to 55%.

[0115] The concave mold wall portion Pcv can exhibit a lower porosity than the horizontal mold wall portion Ph. Preferably, the concave mold wall portion Pcv can have a porosity of 1% to 70%, more preferably 35% to 50%.

[0116] The mold described above can be produced in an additional manufacturing process, such as 3D printing. This additional manufacturing process may include the selective sintering of a powder material having particles with an average size of 1-50 micrometers, preferably 5-30 micrometers. During the sintering process, the powder material is completely melted by applying energy using a laser beam or electron beam.

[0117] The material used to manufacture the mold can be a metal or a metal alloy. Examples of such materials include, but are not limited to, titanium and titanium alloys, as well as aluminum, aluminum alloys, copper and copper alloys, bronze, brass, cobalt and chromium alloys, and stainless steel.

[0118] In an alternative, the material can be a polymer material, such as a plastic material.

[0119] This forming process enables the creation of a porous mold that presents well-defined channels connecting the product surface Fp and the back surface Fb. The material between the channels is homogeneous and at least 95%, preferably 99% or 99.9%, free of voids.

[0120] Refer to the above Figures 1a-1d It should be noted that, according to this disclosure, one or more of tools 10, 20, 30, and 40 may be formed.

[0121] Furthermore, it should be noted that, for example, the picking tool 10 and / or the transfer tool 20 may be formed with thinner walls than the pressing tools 30, 40 and / or made of a material with a lower melting point.

[0122] The tool can be manufactured as a complete tool or as at least two tool parts joined together by brazing, welding, gluing or fusion.

[0123] Furthermore, a tool can be configured as a pair of tool parts with a hinge mechanism connecting the tool parts. Tools configured in this way can allow for the production of even more complex products.

[0124] Figure 4 A portion of the pressing mold wall according to the first embodiment is schematically shown. Figure 4 This involves male molds, but it should be understood that the same design can be used for female molds.

[0125] The pressing mold has a mold wall 101 with a recess 1015, and the heating element 33 is arranged in the recess 1015. The mold wall 101 has a channel 102, which can be adjusted according to... Figure 2a-3 The public formation of any one of them.

[0126] Therefore, the recess and heating element can be formed from elongated leads for resistance heating or channels for conducting heat with liquid or gas. Alternatively, the recess can accommodate a magnetic material that can be heated by induction. This magnetic material can be formed as discrete islands or one or more elongated rods.

[0127] The recess and heating element can span all or part of the back surface. Therefore, the sections of the recess and heating element can be spaced apart from each other as needed.

[0128] The recesses 1015 may extend from their rear into the mold wall. Non-limiting examples of the distance they may extend into the mold wall may be approximately 3 / 4, 1 / 2, or 1 / 4 of the thickness of the mold wall at the relevant wall portion.

[0129] Because the recess opens towards the rear, the heating element 33 can be inserted after the mold wall portion has been produced. The heating element 33 can also be replaced if necessary.

[0130] In this embodiment, the back side Fb is open towards the vacuum chamber 32, where a vacuum can be drawn, such as... Figure 4 The arrow in the middle indicates this.

[0131] Figure 5 A portion of the pressing mold according to the second embodiment is shown schematically. Figure 5 This involves male molds, but it should be understood that the same design can be used for female molds.

[0132] The pressing die includes an outer portion 1011 and a heater portion 1013, with a gap 1021 provided between the outer portion 1011 and the heater portion 1013. A spacer 1012 extends between the heater portion and the outer portion, spanning the gap 1021.

[0133] The channel 102 of the external portion 1011 connects the product surface Fp to the back surface Fb. These channels can be configured according to... Figure 2a-3 The public formation of any one of them.

[0134] The back surface Fb2 of the heater section 1013 may have a recess 1015, in which the following can be determined according to... Figure 4 Any alternatives mentioned for arranging the heating element 33.

[0135] The back of the heater section 1013 can be opened toward the vacuum chamber 32.

[0136] Manifold channel 1022 also connects gap 1021 to the back surface Fb2 of heater section 1013. These manifold channels have a larger cross-section than channel 102, and the number of these manifold channels is less than that of channel 102. For example, the main width of manifold channel 1022 may be approximately 10 to 1000 times the main width of channel 102.

[0137] Furthermore, the number of manifold channels can be approximately 1 / 10 to 1 / 10000 of the number of channels 102. The total flow cross-section of the manifold channel 1022 can be equal to or greater than the total flow cross-section of the channel 102. For example, the total flow cross-section of the manifold channel 1022 can be approximately 100%-300% of the total flow cross-section of the channel 102.

[0138] The external part 1011, the heater part 1013 and the spacer 1012 can be formed as a whole.

[0139] Figure 6 A portion of a pressing mold according to a third embodiment is schematically shown. This embodiment is similar to... Figure 5In this implementation scheme, the mold wall presents an external portion 1011 integrally formed with the spacer 1012. The channel 102 can be formed regarding... Figure 2a-3 and Figure 5 The described channel.

[0140] exist Figure 6 In one embodiment, the heater portion 1013' and the optional spacer 1012 are formed as separate material pieces and are made of a different material than the outer portion 1011. The heating element can be coupled with... Figure 5 The same arrangement as that implemented in the heating section 1013 is implemented in the heater section.

[0141] In an alternative, the heating element 33 can be enclosed within the heating section 1013.

[0142] In any case, the manifold channel 1022 can be relative to Figure 5 The described manner extends through the heater section 1013'.

[0143] The heater section 1013' may include a body formed of a metallic material.

[0144] An insulator 1014 may be provided on the rear side of the heater section 1013'. The insulator may abut against the heater section 1013', or it may be slightly spaced from the heater section 1013', for example, to allow vacuum to be distributed from the inlet channel 1024 through the insulator 1014 to the manifold channel 1022.

[0145] Insulator 1014 can be formed from a rigid insulating material such as ceramic material.

[0146] Insulators can be enclosed in a housing, for example, to prevent them from being damaged.

[0147] Two pressing dies (e.g., male and female) can be provided with insulators. In this case, the insulators can substantially close the dies when they are placed together in the forming position, thereby reducing energy loss. A gap can be provided at the location where the dies meet to allow steam to escape. Alternatively or additionally, through holes can be provided in one or both insulators to allow steam to escape.

[0148] In embodiments where the additional body is arranged near the back of the mold, for example where heaters 1013, 1013' are provided, the spacer can transfer some of the pressure applied to the product surface to the additional body.

[0149] Typically, less than 95% (preferably less than 90%, less than 80%, less than 70%, less than 50%, less than 30%, or less than 10%) of the pressure applied to the product surface can be transferred to the additional body. The untransferred portion of the pressure can be absorbed by the mold due to its own rigidity.

[0150] Depending on the application during the pressing step, the pressure applied to the mold surface can be on the order of at least 100 kPa, at least 25 kPa, at least 450 kPa, at least 800 kPa, or at least 1 mPa.

[0151] The product's front and / or back surfaces may be surface-treated, such as ground or polished, anodized, or coated. This treatment may be provided, for example, to reduce the risk of corrosion compared to the material used to manufacture the mold. The surface treatment or coating may alternatively or additionally provide non-stick properties; for example, it may be more hydrophobic than the material used to manufacture the mold. As another option, the surface treatment or coating may provide a surface with increased hardness compared to the material used to manufacture the mold.

Claims

1. A tool for use in a process of molding a product from a pulp slurry, the tool comprising: a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion presenting porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein the product face presents a first porous surface portion and a second porous surface portion, and wherein the first porous surface portion presents a greater porosity than the second porous surface portion.

2. The tool of claim 1, wherein, The first porous surface portion is a convex surface portion and the second porous surface portion is a planar surface portion.

3. The tool of claim 1, wherein, The first porous surface portion is a planar surface portion and the second porous surface portion is a concave surface portion.

4. A tool for use in a process of molding a product from a pulp slurry, the tool comprising: a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion presenting porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein at least some of the channels present a cross-section tapering towards the product face, wherein the tool wall portion has a thickness of 0.5-10 mm, and wherein the tool wall portion is formed as a piece of homogeneous material with at least 99% void free between the channels.

5. The tool of claim 4, wherein, The tool wall portion is formed as a piece of homogeneous material with at least 99.9% void free between the channels.

6. The tool of claim 4 or 5, wherein, At least some of the channels present a channel opening area at the product face that is smaller than a corresponding channel opening area at the back face.

7. The tool of claim 4 or 5, wherein, The product face has a pair of surface portions that are generally planar and present an angle of 45-135° relative to each other, wherein the surface portion presenting the greatest angle relative to the horizontal plane during the main operation of the tool presents a greater porosity than the other surface portion.

8. The tool of claim 4 or 5, wherein, The product face presents juxtaposed first and second surface portions, and wherein the central axis of channel openings at the first surface portion extends at a different angle relative to the product face of the surface portion at which they open than the central axis of channel openings at the second surface portion.

9. A tool for use in a process of molding a product from a pulp slurry, the tool comprising: a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion presenting porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein the product face has a pair of surface portions that are generally planar and present an angle of 45°-135° relative to each other, wherein the surface portion that presents the greatest angle relative to horizontal during primary operation of the tool presents greater porosity than the other surface portion.

10. A tool part for use in a process of molding a product from a pulp slurry, the tool part comprising: a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion presents porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein the product face presents a first porous surface portion and a second porous surface portion, and wherein the first porous surface portion presents greater porosity than the second porous surface portion.

11. The tool part of claim 10, wherein, the first porous surface portion is a convex surface portion and the second porous surface portion is a planar surface portion.

12. The tooling part of claim 10, wherein, the first porous surface portion is a planar surface portion and the second porous surface portion is a concave surface portion.

13. A tool part for use in a process of molding a product from a pulp slurry, the tool part comprising: a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion presents porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein at least some of the channels present a cross-section that tapers towards the product face, wherein the tool wall portion has a thickness of 0.5-10 mm, and wherein the tool wall portion is formed as a piece of homogeneous material that is at least 99% void free between the channels.

14. The tooling part of claim 13, wherein, the tool wall portion is formed as a piece of homogeneous material that is at least 99.9% void free between the channels.

15. The tool part according to claim 13 or 14, wherein at least some of the channels present a channel opening area at the product face that is less than a corresponding channel opening area at the back face.

16. The tool part according to claim 13 or 14, wherein the product face has a pair of surface portions that are generally planar and present an angle of 45°-135° relative to each other, wherein the surface portion that presents the greatest angle relative to horizontal during primary operation of the tool part presents greater porosity than the other surface portion.

17. The tool part according to claim 13 or 14, wherein the product face presents juxtaposed first and second surface portions, and wherein a central axis of a channel opening at the first surface portion extends at a different angle relative to the product face of the surface portion at which it opens than a central axis of a channel opening at the second surface portion.

18. A tool part for use in a process of molding a product from a pulp slurry, the tool part comprising: a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion presents porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein at least some of the channels present a cross-section that tapers towards the product face, wherein the tool wall portion has a thickness of 0.5-10 mm, and wherein the tool wall portion is formed as a piece of homogeneous material that is at least 99% void free between the channels. the tool wall portion is formed as a piece of homogeneous material that is at least 99.9% void free between the channels. at least some of the channels present a channel opening area at the product face that is less than a corresponding channel opening area at the back face. the product face has a pair of surface portions that are generally planar and present an angle of 45°-135° relative to each other, wherein the surface portion that presents the greatest angle relative to horizontal during primary operation of the tool part presents greater porosity than the other surface portion. the product face presents juxtaposed first and second surface portions, and wherein a central axis of a channel opening at the first surface portion extends at a different angle relative to the product face of the surface portion at which it opens than a central axis of a channel opening at the second surface portion. a self-supporting tool wall portion having a product face for contacting the product and a back face on the other side of the tool wall portion relative to the product face, the tool wall portion exhibits porosity provided by a plurality of channels extending through the tool wall portion from the product face to the back face, wherein the channels are straight or curved with no more than one inflection point, wherein the product face has a pair of surface portions that are generally planar and exhibit an angle of 45°-135° relative to each other, wherein the surface portion that exhibits the greatest angle relative to horizontal during the primary operation of the tooling part exhibits greater porosity than the other surface portion.

Images