DE102019120854B4 - Manufacturing process and device as well as fiber-cast cups manufactured according to the manufacturing process - Google Patents

Abstract

Manufacturing process for cast fiber products in which a suction mold with a porous wall is immersed in a water-fiber mixture and a fiber layer is formed on the suction mold by sucking in the water, the suction mold being composed of at least two partial molds (1, 2, 3) and in order to separate the fiber layer from the suction mold, the partial molds (1, 2, 3) are separated from one another, characterized in that the partial molds (1, 2, 3) are placed on a carrier (4) which has at least one porous wall section (11 , 12, 13, 21, 22, 23).

Description

The invention relates to a manufacturing method according to the preamble of claim 1, a molded fiber cup according to this method and a manufacturing device according to the preamble of claim 8 for molded fiber products, wherein a suction mold with a porous wall is immersed in a water-fiber mixture and a fiber layer is formed on the suction mold by sucking in the water.

In the manufacture of products using the fiber casting process, water is sucked off using a suction mold, which is immersed in a mixture of fibers and water. For this purpose, the suction mold has at least one porous wall. During this process, the fibers are deposited on the porous wall of the immersed suction mold and follow its surface. The mostly thin-walled fiber body formed in this way is then dried.

A conventional molding tool for the production of fiber cast products is from the document DE 198 32 399 A1 known. The suction mold here consists of a three-dimensional support structure which supports a sieve-like, thin-walled body that forms the porous wall of the suction mold. Another form of suction is printed matter WO 2016/101976 A1 refer to. The pamphlets EP 1 015 696 B1 and DE 10 2017 219 812 A1 contain suggestions for the production of suction molds with porous wall sections in additive manufacturing processes (3D printing).

With the well-known suction molds, cast fiber products can be manufactured in various contours. However, it is difficult to produce cast fiber products with undercuts, since these usually cannot be removed from the suction mold without destroying the cast fiber product.

The pamphlets US 2004/0 011 489 A1 and DE 699 35 784 T2 describe processes for the production of hollow fiber bodies by means of two-part fiber casting molds. The pamphlet DE 879 355 B describes a process for the production of cup-like molded bodies made of cast fiber with molds which have movable wall sections for releasing the molded body.

The object of the invention is to propose a manufacturing method for cast fiber products which enables a greater variety of shapes for cast fiber products.

According to the invention, this object is achieved by the entirety of the features of claim 1 or claim 8.

The suction mold is composed of at least two part molds and the part molds are separated from one another in order to separate the fiber layer from the suction mold.

The fact that the suction mold is put together enables the manufacture of complex molded fiber cast products. The cast fiber products can have protrusions, undercuts, corners and edges. By separating the part molds, the undercuts can be released from the part molds, which is not possible with a contiguous suction mold.

In particular, to implement the proposed method, partial molds are manufactured from plastic or metal using the additive manufacturing method. Additive manufacturing processes such as 3D printing are easily suitable for the production of complex component geometries. In the additive manufacturing process, porous and solid wall sections can also be combined with one another as required.

In this way, complex shapes of a suction mold and its partial molds can be realized, which are put together so that the fibers are sucked out of the pulp in the predetermined areas of the porous surfaces of the suction molds and the water is directed to a central suction device.

An example of a complex form of a cast fiber product, described in detail below, is a cup with ribs on its outer wall and an annular bead in the bottom area. Such contours cannot be realized with the one-piece suction molds known up to now.

The suction mold can, for example, be composed of two partial molds if projections with undercuts are provided on two opposite sides of the cast fiber product. If several projections are provided on the cast fiber product distributed over the circumference, three or more partial molds combined with one another can also form the suction mold in practice.

The partial molds are placed on a carrier which has at least one porous wall section. In particular, at least one porous wall section of the partial mold can bear against a porous wall section of the carrier. The carrier can be connected to a suction device which generates a negative pressure on its rear side, which is conducted through the porous wall section to the side of the porous wall section of the carrier against which the partial mold rests. The negative pressure is transmitted to the porous wall section of the part mold. Water that is sucked in through the part mold passes through its porous part Wall section through into the porous wall section of the carrier and from there to the suction device. For example, the carrier can define a base section of the manufactured fiber cast product, the partial shapes defining wall sections of the fiber cast product. The suction device is connected to the carrier and sucks water through porous wall sections of the carrier. Some porous wall sections of the carrier can open into the pulp (water-fiber mixture) and attract a fiber layer. Other porous wall sections of the carrier can rest against porous wall sections of the partial mold and thus transfer the negative pressure from the suction device to the partial mold, which in turn sucks in fibers which are deposited as a layer on its surface.

By means of at least one connecting element, either a plurality of partial shapes or at least one partial shape can be connected to a carrier during suction. The connecting element stabilizes the suction mold formed by the part molds and optionally the carrier. The connecting element can for example be formed by a clamping collar in the case of partial molds which each form peripheral sections of the suction mold. Partial molds, which form several suction molds, can be connected by projections which are designed as pins and protrude into bores in the respective other mold part. Buckles or clips or notches can also be used as connecting elements. Furthermore, the molded parts can be designed to be complementary, so that they can be plugged into one another and are fixed to one another due to the negative pressure of the suction device.

In practice, in the production method according to the invention, a transfer mold can be pressed against the fiber layer in the suction mold. A transfer mold and shaping steps carried out by the transfer mold make it possible to realize precise shapes in the cast fiber product. On the one hand, pressing a transfer mold onto a fiber layer that is formed on the suction mold compresses the fiber layer and smooths the side of the cast fiber product facing away from the porous wall of the suction mold. Water can also be sucked off through the transfer mold, so that the fiber layer is sucked against a porous wall of the transfer mold by a negative pressure. The suction pressure acting on the fiber layer can increase the mechanical pressure with which the transfer mold is pressed against the fiber layer on the suction mold. Furthermore, the fiber layer can be heated in the transfer mold. This accelerates the drying of the cast fiber product.

• - die porösen Wandabschnitte der Teilformen und des Trägers bilden eine Mulde, in der sich eine schalenförmige Faserschicht ablagert;
• - die porösen Wandabschnitte der Teilformen und/oder des Trägers weisen Vertiefungen auf, so dass sich an der schalenförmigen Faserschicht Vorsprünge bilden;
• - die Vertiefungen haben die Form von Nuten, so dass die Vorsprünge die Form von Rippen aufweisen;
• - die Teilformen und/oder der Träger und/oder die Transferform wird durch ein additives Fertigungsverfahren hergestellt;
• - mehrere Teilformen benachbarter Saugformen werden einstückig als ein Bauteil zusammengefasst.

Furthermore, the following additional features can be implemented in practice in the production method according to the invention:

• - The porous wall sections of the part molds and the carrier form a trough in which a bowl-shaped fiber layer is deposited;
• the porous wall sections of the partial molds and / or of the carrier have depressions, so that projections are formed on the shell-shaped fiber layer;
• the recesses are in the form of grooves so that the projections are in the form of ribs;
• - The part molds and / or the carrier and / or the transfer mold is produced by an additive manufacturing process;
• - Several partial molds of adjacent suction molds are combined in one piece as one component.

A trough-shaped suction mold enables the production of a drinking vessel or other vessel for holding food. In particular, a drinking cup for warm drinks can be produced with the production method described here.

By assembling the suction mold from partial molds and, if necessary, a carrier, it is possible to provide depressions in the suction mold so that the shell-shaped fiber casting product has projections. In particular, the depressions can have the shape of grooves which run essentially in axial planes of the shell-shaped fiber cast product and are distributed around its circumference. Ribs form on the cast fiber product when the fibers are sucked in. The ribs increase the thermal insulation of a warm liquid in the bowl-shaped cast fiber product and reduce the risk that a consumer who is holding the cast fiber product in his hands will get burned.

As described at the outset, the part molds and carriers and in particular their porous wall sections can be produced from plastic materials or metals using an additive manufacturing process, in particular 3D printing. In additive manufacturing processes, the structure of the molded part can be implemented in thin layers, the layers optionally having closed material sections and porous material sections. In this way it is possible to produce porosities which lead from a certain surface, which is intended for sucking up the pulp, to another surface, to which a suction device is connected.

In practice, several partial molds of adjacent suction molds can be combined in one piece as a component. For example it is possible to produce a matrix with a large number of suction molds adjacent to one another. This matrix can be placed on a single carrier, which defines the bottom area of all fiber cast products produced. The matrix has several rows of mutually adjacent and identically shaped suction molds. The partial molds of the suction molds can be combined into blocks so that all partial molds of a series of suction molds form a block. It is important to ensure that all partial forms of a block are moved together. The suction molds are opened simultaneously and uniformly by moving a block. The consequence of this is that all partial molds that are combined to form a block are moved in the same direction during the opening movement.

The manufacturing method described above makes it possible, in particular, to manufacture a cast fiber cup which has a bowl-shaped or chalice-shaped shape and is characterized in that it has a plurality of ribs which extend in axial planes of the cup. Alternatively and / or additionally, the cup can have a bead opposite its edge, i.e. in the area of its bottom, which forms a contact surface. Alternatively and / or additionally, the cup can have a waterproof coating.

Finally, the invention relates to a device for producing cast fiber products with a suction mold which has a porous wall, the suction mold consisting of at least two partial molds. To achieve the above-mentioned object, the device has a carrier on which the partial molds (1, 2, 3) can be placed and which has at least one porous wall section (5, 6).

In practice, the production device can have the further features described above.

• 1 zeigt eine dreidimensionale Explosionsansicht einer erfindungsgemäßen Saugform mit Transferform und durch diese Form hergestelltem Faserguss-Becher.
• 2 zeigt eine Seitenansicht einer aus den in 1 gezeigten Teilen hergestellten Saugform ohne Transferform.
• 3 zeigt eine Draufsicht auf die Saugform aus 2 ohne Transferform.
• 4 zeigt eine zur 1 ähnliche Darstellung der Saugform mit Transferform und von der Transferform gelöstem Faserguss-Becher.
• 5 zeigt eine Seitenansicht des Faserguss-Bechers aus 4.

Further practical embodiments and advantages of the invention are described below in connection with the drawings.

• 1 shows a three-dimensional exploded view of a suction mold according to the invention with a transfer mold and a molded fiber cup produced by this mold.
• 2 FIG. 13 shows a side view of one of the FIGS 1 Parts shown produced suction mold without transfer mold.
• 3 FIG. 4 shows a top view of the suction mold from FIG 2 without transfer form.
• 4th shows a to 1 Similar representation of the suction mold with the transfer mold and the cast fiber cup detached from the transfer mold.
• 5 FIG. 13 shows a side view of the molded fiber cup from FIG 4th .

The particular in the 1 and 4th The recognizable suction form consists of three sub-forms 1 , 2 , 3 , which each make up a third of the circumference of the suction mold. The three partial forms 1 , 2 , 3 act with a carrier 4th together.

Any part shape 1 , 2 , 3 has an inner wall 11 , 12th , 13th on, which is porous. On the one hand in the area of the inner wall 11 , 12th , 13th On the other hand, opening pores open in the area of the base area 21 , 22nd , 23 of the partial forms 1 , 2 , 3 . The outward facing peripheral surface 31 , 32 , 33 of the partial forms 1 , 2 , 3 is designed to be closed. No pores open here. The pores allow water from the inner surfaces 11 , 12th , 13th to the base areas 21 , 22nd , 23 of the partial forms 1 , 2 , 3 be sucked.

The carrier 4th has an annular surface 5 on, which is also made porous. Below the ring surface 5 A negative pressure can be generated, so that fluids through the porous ring surface 5 can be sucked through. When the part forms 1 , 2 , 3 onto the porous ring surface of the carrier 4th are placed, a fluid will flow through the inner surface 11 , 12th , 13th of the partial forms 1 , 2 , 3 over their base 21 , 22nd , 23 and the ring surface 5 of the wearer 4th sucked and steps on the in 1 lower side of the carrier 4th the end. A suction device (not shown) can be arranged here, which draws in the water from the water-fiber mixture. The circumference of the ring area 5 is of an annular protrusion 20th surrounded by the ones on the carrier 4th attached part forms 1 , 2 , 3 to each other and to the wearer 4th aligns and fixes.

The end walls 7th in the circumferential direction, which run along an axial plane of the suction mold, can also be designed to be closed, so that no fluid flow from a partial mold 1 , 2 , 3 to the next one. Also the central area 6th of the wearer 4th is made porous, so that fiber material is sucked in here, which the floor 15th a mug 14th which is formed by the suction mold (cf. 5 ).

Any part shape 1 , 2 , 3 points on its porous inner surface 11 , 12th , 13th Ledges 8th on that by grooves 9 separated from each other. Accordingly, fiber material is deposited on the porous inner surface 11 , 12th , 13th the partial form 1 , 2 , 3 with ribs 17th in the wall areas of the cup 14th off that in the grooves 9 the partial form 1 , 2 , 3 lie. In the area of the end walls 7th joins the adjacent protrusions 8th an offset area that is half the width of a Has groove. In this way, also arise in the areas of the mutually abutting end walls 7th neighboring partial forms 1 , 2 , 3 Grooves 9 which lead to the formation of ribs 17th on the outside of the mug 14th to lead.

Due to the separable part forms 1 , 2 , 3 and also from the partial forms 1 , 2 , 3 detachable carrier 4th can be in the area of the ribs 17th of the cup made of cast fiber 14th and in the area of the upper edge 16 of the mug 14th and in the area of the contact area or the ground 15th of the mug 14th Undercuts arise. Due to the separability of the partial forms 1 , 2 , 3 and the wearer 4th can the mug 14th can be removed from the suction mold without being damaged.

the 2 shows the suction mold in its assembled configuration, in which it is dipped in pulp and placed on the in 2 back of the carrier shown below 4th is applied with a suction pressure. It can be seen that the partial forms 1 , 2 , 3 by a connecting element 10 are connected to each other. The connecting element 10 is a cuff made of a textile tape or a metal foil, which forms the part 1 , 2 , 3 firmly connects. Great forces have to go through the connecting element 10 not be applied because the part forms 1 , 2 , 3 by the negative pressure on the underside of the wearer 4th acts, contracted and against the wearer 4th to be pulled. Alternative connecting elements between the part molds 1 , 2 , 3 and optionally between the carrier 4th and the partial forms 1 , 2 , 3 can be provided. For example, resilient latching projections can engage in corresponding latching recesses which fix the parts in relation to one another.

In 4th is, after all, a form of transfer 18th to see which has a bell-shaped, downward protruding section 19th in the cup formed from the deposited fibers 14th is pushed in. By pressing the inside of the wall of the cup consisting of deposited fibers 14th smoothed. The bell-shaped section 19th can also consist of a porous wall so that moisture can be sucked off through it. Alternatively and / or in addition, the bell-shaped section 19th be heatable in order to dry the formed cup 14th to accelerate.

In the drawings there is schematically a prototype of a suction mold for a single cup 14th shown, which consists of several partial forms 1 , 2 , 3 and a carrier 4th and the one with a transfer form 18th cooperates. In practice, a large number of shapes can be combined to produce a large number of molded fiber products. A carrier can be formed which has a matrix of receptacles for a plurality of shapes, which are arranged in rows and columns adjacent to one another. In this case, partial forms 1 , 2 , 3 belonging to several suction forms can be combined into one unit. In this case, a connecting element can comprise the units with the several partial forms 1 , 2 , 3 connect which form the plurality of suction molds.

As mentioned, the partial forms 1 , 2 , 3 the porters 4th as well as the transfer form 18th can be produced by additive manufacturing processes (3D printing). Plastic is particularly suitable as a manufacturing material. Especially for the production of the transfer mold 18th however, a metal can also be used so that the transfer mold can transmit a higher pressing force.

Additive manufacturing processes make it possible to create pores or small channels in the part shapes 1 , 2 , 3 , the carrier 4th and the transfer form 18th bring in. In addition, it is possible to have closed sections, such as the end walls 7th and the outer peripheral surfaces 31 , 32 , 33 of the partial forms 1 , 2 , 3 to manufacture.

The features of the invention disclosed in the present description, in the drawings and in the claims can be essential both individually and in any combination for the implementation of the invention in its various embodiments. The invention is not restricted to the embodiments described. It can be varied within the scope of the claims and taking into account the knowledge of the competent person skilled in the art.

List of reference symbols

1

Partial form

2

Partial form

3

Partial form

4th

carrier

5

porous ring surface

6th

middle section

7th

Front wall

8th

head Start

9

Groove

10

Connecting element

11

porous inner surface

12th

porous inner surface

13th

porous inner surface

14th

cups

15th

floor

16

edge

17th

rib

18th

Transfer form

19th

bell-shaped section

20th

annular projection

21

Floor space

22nd

Floor space

23

Floor space

31

Circumferential surface

32

Circumferential surface

33

Circumferential surface

Claims (12)

Manufacturing process for cast fiber products in which a suction mold with a porous wall is immersed in a water-fiber mixture and a fiber layer is formed on the suction mold by sucking in the water, the suction mold being composed of at least two partial molds (1, 2, 3) and in order to separate the fiber layer from the suction mold, the partial molds (1, 2, 3) are separated from one another, characterized in that the partial molds (1, 2, 3) are placed on a carrier (4) which has at least one porous wall section (11 , 12, 13, 21, 22, 23). Manufacturing process according to Claim 1 , characterized in that at least one porous wall section (21, 22, 23) of the partial mold (1, 2, 3) rests against a porous wall section (5) of the carrier (4) and is sucked through the partial mold (1, 2, 3) Water is sucked through the porous wall section (5) of the carrier (4). Manufacturing method according to one of the preceding claims, characterized in that during suction at least one connecting element (10) connects the following elements to one another: - several partial molds (1, 2, 3); - At least one part shape (1, 2, 3) and a carrier (4). Manufacturing method according to one of the preceding claims, characterized in that a transfer mold (18) is pressed against the fiber layer formed in the suction mold. Manufacturing process according to Claim 4 , characterized by at least one of the following features: - water is sucked off through the transfer mold (18); - The fiber layer is heated in the transfer mold (18). Manufacturing method according to one of the preceding claims, characterized by at least one of the following features: - the porous wall sections of the part molds (1, 2, 3) and of the carrier (4) form a trough in which a shell-shaped fiber layer is deposited; - The porous wall sections (11, 12, 13) of the partial molds (1, 2, 3) and / or of the carrier (4) have depressions (9) so that projections (17) are formed on the shell-shaped fiber layer; - the recesses are in the form of grooves (9) so that the projections are in the form of ribs (17); - The part molds (1, 2, 3) and / or the carrier (4) and / or the transfer mold (18) is produced by an additive manufacturing process; - Several partial molds (1, 2, 3) of adjacent suction molds are combined in one piece as one component. Cast fiber cup (14) which is produced according to a method according to at least one of the preceding claims and has a bowl-shaped or goblet-shaped shape, characterized in that at least one of the following features has: - a plurality of ribs (17) extending in axial Extend levels; - a bead opposite its edge (16) which forms a contact surface; - a waterproof coating. Apparatus for the production of cast fiber products, with a suction mold which has a porous wall, the suction mold consisting of at least two part molds (1, 2, 3), characterized in that it has a carrier (4) on which the part molds (1, 2, 3) can be attached and which has at least one porous wall section (5, 6). Device according to Claim 8 , characterized in that at least one porous wall section (21, 22, 23) of an attached part mold (1, 2, 3) rests against a porous wall section of the carrier (4) so that sucked through the part mold (1, 2, 3) Water is sucked through the porous wall section (5) of the carrier (4). Device according to Claim 8 or 9 , characterized in that it has at least one connecting element (10) which connects the following elements to one another during suction: - several partial molds (1, 2, 3); - At least one part shape (1, 2, 3) and a carrier (4). Device according to one of the Claims 8 until 10 , characterized by a transfer mold (18) which can be pressed against a fiber layer formed in the suction mold. Device according to one of the Claims 8 until 11 , characterized by at least one of the following features: - the porous wall sections (11, 12, 13) of the partial molds (1, 2, 3) and of the carrier (4) form a trough in which a shell-shaped fiber layer is deposited; - The porous wall sections (11, 12, 13) of the partial molds (1, 2, 3) and / or of the carrier (4) have depressions (9) so that projections (17) are formed on the shell-shaped fiber layer; - the recesses are in the form of grooves (9) so that the projections are in the form of ribs (17); - The part molds (1, 2, 3) and / or the carrier (4) and / or the transfer mold (18) are produced by an additive manufacturing process; - Several partial molds (1, 2, 3) of adjacent suction molds are combined in one piece as one component.

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