Method for patterning extrusion-molded plate and device for manufacturing same

Abstract

The present invention improves finishing accuracy when a composite pattern with a large height difference including a groove part (12) extending in an extrusion direction is formed on the surface of an extrusion-molded plate. A mouthpiece (51) of an extrusion molding machine is provided with a protruding part (52) for shaping the rough shape of the groove part (12), and a flat part (53) for shaping a main surface part (13) other than the groove part (12). The peripheral surface of a roller (70) installed on the downstream side of a discharge port (50) is provided with a protruding strip (72) that is continuous with the protruding part (52) of the mouthpiece (51) and shapes the finished shape of the groove part (12), and a pattern transfer part (73) that shapes a pattern of recesses and protrusions on the main surface part (13). The width of the protruding strip (72) is smaller than the width of the protruding part (52) of the mouthpiece (51). The installation height of the roller (70) is set so that, at the lowest position of the peripheral part of the roller (70), the height of the peripheral surface of the protruding strip (72) is the same as the height of the lower end surface of the protruding part (52) of the mouthpiece (51), and the height of the pattern transfer part (73) is smaller than the height of the flat part (53) of the mouthpiece (51).

Description

Method and apparatus for patterning extruded sheets

[0001] The invention disclosed in this application relates to a method for beautifully forming a grooved and uneven pattern on the surface of an extruded panel used as an exterior wall material or the like when manufacturing an extruded panel using a cement-based material or a clay-based material, and to a manufacturing apparatus for carrying out this method.

[0002] As a technique for forming a continuous relief pattern in the extrusion direction on the surface of an extruded sheet, for example, the "Method for Manufacturing an Extruded Sheet Having a Deep Embossed Pattern" described in Patent Document 1 is known. To create a relief pattern on the surface of an extruded sheet, it is common to press a roller with a pattern on its circumferential surface against it. However, the manufacturing method described in Patent Document 1 employs an endless belt that extends in the extrusion direction and rotates continuously in order to form a pattern with a long repeat span. An inclined groove is provided on the upper surface of the die of the discharge port of the extruder, and a guide box and pressure-adjustable press roller are arranged along the inclined groove. By synchronizing the rotation speed of the endless belt with the discharge speed of the raw sheet and bringing it into close contact with the surface of the raw sheet, a deep relief pattern (embossed pattern) can be formed with high precision.

[0003] However, the manufacturing method described in Patent Document 1 is configured to form a pattern with substantially uniform depth of irregularities on a flat surface raw plate. Therefore, in areas where the amount of material (mixed extruded material) moves between the recesses and protrusions of the pattern is large (for example, near deep grooves that are continuous in the extrusion direction), the material may move unevenly. When the belt detaches from the surface of the raw plate, chipping or cracking may occur in the stepped portion of that area, or deformation may occur during drying due to residual stress between the recesses and protrusions.

[0004] As a technique for forming such a complex pattern with a large height difference, the "Method for Manufacturing an Embossed Extruded Cement Board and Its Apparatus" described in Patent Document 2 is also known. The manufacturing method is shown in FIG. 3. The reference numerals in FIG. 3 are the same as those in Patent Document 2. In the manufacturing method described in this document, first, concave portions 31a and convex portions 31b are alternately provided in advance on the die 31 of the discharge port, and high platform-shaped ribs 33 and the rough shape of the concave portions 23b between the ribs 33 are formed on the surface of the green board 23 extruded from the discharge port. Next, an endless belt 37 provided with an embossing portion 37a for transferring a shallow concavo-convex pattern 43 to the surface of the rib 33 and a rib 37b for forming the finished shape of the concave portion 23b is further adhered, and the shapes of the rib 33 and the concave portion 23b are finished. Thus, even when forming a complex pattern with a large height difference, the amount of material movement between the convex portion and the concave portion can be reduced, and the finishing accuracy can be improved.

[0005] Japanese Patent Publication No. 1-23289, Japanese Unexamined Patent Application Publication No. 2006-007458 <000001-1><000001-2>According to the drawings in the said Patent Document 2, the manufacturing method described in the said patent document is such that the height difference of the embossing portion 43 and the rib 37b of the endless belt 37 provided on the downstream side thereof is set to be larger than that of the rough shapes of the rib 33 and the concave portion 23b formed on the surface of the green board 23 by the concave portion 31a and the convex portion 31b provided on the die 31 of the discharge port. When such an endless belt 37 is pressed against the surface of the green board 2 where the rough shapes of the rib 33 and the concave portion 23b are formed, as shown in the enlarged view in FIG. 3, a volume of material corresponding to the amount by which the bottom surface of the concave portion 23b is pushed down by the rib 37b of the endless belt 37 moves to the portion that raises the embossed pattern 43 on the surface of the rib 33. According to the verification by the applicant of the present application, when the amount of material movement in the height direction of the pattern is large in this way, it is still difficult to prevent molding defects at the corners, deformation during drying, cracking, etc., and improvement is required.

[0007] The invention disclosed in the present application is conceived based on such findings, and an object thereof is to provide a method for embossing an extruded plate and a manufacturing apparatus that can obtain high finishing accuracy even when forming a complex pattern with a large height difference.

[0008] The present invention provides a method for patterning an extruded sheet, wherein a mixture made of cement-based or clay-based material is extruded from the discharge port of an extruder, and while the uncured sheet is conveyed in the extrusion direction, the endless circumferential surface of a pattern transfer device installed downstream of the extruder is brought into close contact with the surface of the sheet to transfer a pattern formed on the circumferential surface to the sheet. The die positioned above the discharge port of the extruder is provided with a downward-facing convex portion that forms the rough shape of the grooves extending in the extrusion direction and a flat portion that forms the main surface portion other than the grooves, while the circumferential surface of the pattern transfer device is provided with the finished shape of the grooves continuous with the convex portion. The pattern transfer device is characterized by having a raised ridge and a pattern transfer section that forms an uneven pattern on the main surface, and by setting the width of the raised ridge to be smaller than the width of the protrusion of the die, and by adjusting the installation height of the pattern transfer device so that the height of the circumferential surface of the raised ridge at the lowest position of the circumferential part of the pattern transfer device is the same as the height of the lower end surface of the protrusion of the die, and the height of the pattern transfer section at the lowest position of the circumferential part of the pattern transfer device is lower than the height of the flat part of the die, thereby moving the kneaded material forming the raw plate in a direction that reduces the width of the grooves when the circumferential surface of the pattern transfer device is brought into close contact with the raw plate.

[0009] Furthermore, the extruded sheet manufacturing apparatus of the invention disclosed in this application comprises: an extruder that extrudes a mixture made of cement-based or clay-based material from the discharge port of an extruder to form an unhardened green sheet; a conveying device that conveys the green sheet in the extrusion direction; and a pattern transfer device installed downstream of the extruder that brings an endless circumferential surface into close contact with the surface of the green sheet and transfers a pattern formed on the circumferential surface to the green sheet, wherein the die positioned above the discharge port of the extruder has a downward-facing convex portion that forms the rough shape of a groove extending in the extrusion direction, and a flat portion that forms the main surface portion other than the groove While a portion is provided, the circumferential surface of the pattern transfer device is provided with a raised ridge that continuously forms the finished shape of the groove portion in the convex portion, and a pattern transfer portion that continuously forms an uneven pattern on the main surface portion. The width of the raised ridge is set to be smaller than the width of the convex portion of the nozzle, and the installation height of the pattern transfer device is set such that the height of the circumferential surface of the raised ridge at the lowest position of the circumferential surface of the pattern transfer device is the same as the height of the lower end surface of the convex portion of the nozzle, and the height of the pattern transfer portion at the lowest position of the circumferential surface of the pattern transfer device is lower than the height of the flat portion of the nozzle.

[0010] According to the extruded sheet patterning method and manufacturing apparatus configured as described above, even when forming a complex pattern with large height differences including grooves on the surface of the raw sheet, the finishing accuracy can be improved, making it less prone to cracking and deformation.

[0011] This is a cross-sectional view of the main part showing the schematic configuration of an extruded sheet manufacturing apparatus according to one embodiment of the invention disclosed in this application. This is an explanatory diagram of the pattern formation state in parts A to D of the manufacturing apparatus in Figure 1. This is an explanatory diagram of the pattern formation state by the extruded sheet manufacturing apparatus described in Patent Document 2.

[0012] Hereinafter, embodiments of the invention disclosed in this application will be described with reference to the drawings. Figure 1 shows a schematic configuration of an extruded sheet manufacturing apparatus (hereinafter simply referred to as the "manufacturing apparatus"), and Figure 2 shows the pattern formation state in parts A to D of the manufacturing apparatus in Figure 1. In the following, when describing the relative positional relationships and directions of operation of parts and components, the viewpoint in Figure 2, which is viewed from the downstream side of the extrusion direction (leftward in Figure 1) and perpendicular to the extrusion direction, will be used as the reference point to specify the vertical direction (height direction) and the horizontal direction (width direction).

[0013] The manufacturing apparatus comprises an extrusion molding machine 5 that extrudes a mixture 10 mainly consisting of cement-based materials and clay-based materials from a discharge port 50 to form an unhardened green sheet 1; a conveying device 6 that transports the extruded green sheet 1 substantially horizontally in the direction of extrusion; and a pattern transfer device 7 installed downstream of the extrusion molding machine 5 that transfers a pattern formed on an endless circumferential surface to the surface of the green sheet 1 by making it adhere to the surface of the green sheet 1.

[0014] The main body of the extrusion molding machine 5 is not significantly different from those described in, for example, Patent Documents 1 and 2, and is composed of a combination of a cylinder (not shown) surrounding the pumping passage for the kneaded material 10, a screw built into the pumping passage, upper and lower dies 51 and 55 for shaping and discharging the kneaded material 10 into a plate, and a hollow pin (intermediate ball) 56 for forming a hollow portion 11 in the green plate 1. The conveying device 6 is composed of, for example, a free roller (not shown) and a belt conveyor 61 that rotates an endless take-up belt with a drive motor, and the belt conveyor 61 is controlled via an appropriate control device to synchronize with the extrusion speed of the green plate 1.

[0015] In the exemplary embodiment, the pattern transfer device 7 employs a large-diameter metal roller 71 with a textured surface. However, a pattern transfer device of the type that rotates an endless belt extended in the extrusion direction, as described in Patent Documents 1 and 2, can also be used. In this specification, a device having such an endless surface that transfers a repetitive and continuous textured pattern is collectively referred to as a "pattern transfer device." The textured pattern may be configured to allow for the appropriate exchange of various types.

[0016] The manufacturing apparatus according to the invention disclosed herein is configured primarily to form multiple grooves 12 with a uniform cross-section that mimic joints extending linearly along the extrusion direction on the surface of an extruded sheet at appropriate intervals, and to transfer an uneven pattern with a smaller height difference than the grooves 12 onto a raised main surface portion 13 formed between the parallel grooves 12. The main surface portion 13 is intended to be formed with an uneven pattern that is not uniform in the extrusion direction (a pattern that changes in the vertical or horizontal direction relative to the extrusion direction), but it is of course also possible to form a pattern that is uniform in the extrusion direction.

[0017] The essential part of this invention lies in the dimensional and positional relationships of the shaping means provided on the die 51 positioned above the discharge port 50 of the extrusion molding machine 5 and on the circumferential surface of the metal roller (hereinafter simply referred to as "roller") 70 that constitutes the pattern transfer device 7.

[0018] A die 51, as shown in Figure 2A, is attached to the upper side of the discharge port 50 of the extrusion molding machine 5. This die 51 is provided with a downward-facing convex portion 52 that forms the rough shape of the groove portion 12 on the surface of the raw sheet 1 extruded from the discharge port 50, and a flat portion 53 without irregularities that forms the main surface portion 13 other than the groove portion 12. The convex portion 52 is formed to have an inverted isosceles trapezoidal cross-sectional shape that narrows downward in the direction perpendicular to the extrusion direction, and both sides and the lower end surface are finished smoothly. The flat portion 53 is also finished to be a smooth horizontal surface without irregularities. On the surface of the raw sheet 1 extruded from the discharge port 50 via this die 51, a rough groove portion 12 extending in the extrusion direction and a flat main surface portion 13 other than the groove portion 12 are formed. The dashed lines marked with "▽" in Figures 1 and 2 indicate the height of the flat portion 53 of the nozzle 51, that is, the height of the main surface portion 13 of the raw plate 1 before the pattern is formed.

[0019] A roller 70 is positioned downstream of the nozzle 51. The circumferential surface of the roller 70 is provided with a raised ridge 72 that forms the finished shape of the groove 12, continuous with the protrusion 52 of the nozzle 51, and a pattern transfer section 73 that continuously forms an uneven pattern on the main surface 13, both of which are provided continuously in the circumferential direction of the roller 70. The cross-sectional shape of the raised ridge 72 is approximately similar to the cross-sectional shape of the protrusion 52 of the nozzle 51, and its width is slightly smaller than the width of the protrusion 52 of the nozzle 51, and its height is slightly smaller than the height of the protrusion 52 of the nozzle 51. This "slight" difference is determined according to the height difference of the uneven pattern formed on the main surface 13 (the volume of material filling that height difference) and the cross-sectional dimensions of the groove 12, etc.

[0020] The roller 70 is installed with its circumferential surface close to the discharge port 50 of the extrusion molding machine 5. In the exemplary configuration, the upper surface of the die 51 of the discharge port 50 is formed to slope downward toward the extrusion side along the circumferential surface of the roller 70, and the roller 70 is installed such that the protrusions 72 of the roller 70 fit into the grooves 54 formed on the inclined surface. This allows the protrusions 72 of the roller 70 to smoothly enter the grooves 12 of the raw sheet 1 formed by the protrusions 52 of the die 51. The roller 70 is also equipped with a fine adjustment function that allows its installation height (distance from the raw sheet 1) to be optimized according to the height difference of the uneven pattern and the depth of the grooves 12.

[0021] Position A in Figures 1 and 2 indicates the area directly in front of the discharge port 50. At position A, the surface of the raw plate 1 is in close contact with the convex portion 52 and the flat portion 53 of the nozzle 51, forming the rough shape of the groove portion 12 and the main surface portion 13. However, the circumferential surface of the roller 70 is still located above the raw plate 1. When the roller 70 moves to position B, it first brings the raised portion of the uneven pattern provided on the pattern transfer portion 73 into contact with the main surface portion 13 of the raw plate 1. However, at this position, the circumferential surface of the convex ridge 72 of the roller 70 has not yet reached the bottom surface of the groove portion 12.

[0022] Then, as the roller 70 moves towards position C in Figures 1 and 2, that is, the lowest position on its periphery, the circumferential surfaces of the raised ridges 72 and the pattern transfer section 73 become lower. At position C, the height of the circumferential surface of the raised ridges 72 becomes the same as the height of the lower end surface of the protrusion 52 on the nozzle 51, and the circumferential surface of the raised ridges 72 comes into contact with the bottom surface of the groove 12. As the pattern transfer section 73 of the roller 70 moves to position C, it presses the entire raised and recessed pattern against the surface of the raw plate 1, pushing down the main surface 13 and forming the raised and recessed pattern at a position lower than the height of the flat section 53 marked with a "▽". At this time, the material of the main surface 13 pressed by the pattern transfer section 73 is pushed not downwards, but to the side of the main surface 13, that is, towards the groove 12. In this invention, the width of the protrusion 72 is set to be smaller than the width of the protrusion 52 on the die 51, so that the material pushed laterally is shaped into the finished shape of the groove 12 while reducing its width. The bottom surface of the groove 12 is carried over at the same height from the lower end surface of the protrusion 52 on the die 51 to the circumferential surface of the protrusion 72 on the roller 70, so the amount of material movement in the height direction is extremely small.

[0023] The raised ridges 72 and pattern transfer section 73 of the roller 70 detach from the raw plate 1 as they move past position C to position D in Figures 1 and 2, completing the pattern application to the raw plate 1. When the pressing force from the roller 70 is released, the pattern remains on the raw plate 1, making it less likely for residual stress to occur even in areas with height differences. In this way, when forming a pattern by pressing the surface of the raw plate 1, optimizing the positional and dimensional relationships between the raised portion 52 and flat portion 53 of the die 51 and the raised ridges 72 and pattern transfer section 73 of the roller 70 allows the pushed material to move laterally without force, reducing the width of the groove portion 12. This makes it possible to achieve high finishing accuracy and reduce cracking and deformation, even when forming complex patterns with large height differences. After the pattern application is completed, the extruded plate is completed through drying, curing, or firing processes depending on the type of material.

[0024] Furthermore, the technical scope of the invention disclosed in this application should not be interpreted restrictively by the exemplary embodiments, but rather conceptually based on the claims. The names of the components used in the claims and specification are for convenience to facilitate a concrete understanding of the invention, and the names do not unnecessarily limit the concept or properties of the components. When implementing the invention disclosed in this application, the detailed shape, dimensions, structure, material, quantity, combination form with other elements, relative positional relationship, etc., of components not specifically identified in the claims may be modified as appropriate, within the scope of using a substantially equivalent operating principle to that of the exemplary embodiment, or within the scope of obtaining substantially equivalent or better effects than those of the exemplary embodiment.

[0025] 1 Raw plate 10 Mixed material 11 Hollow section 12 Groove section 13 Main surface section 5 Extrusion molding machine 50 Discharge port 51 Die (upper) 52 Convex section 53 Flat section 54 Groove 55 Die (lower) 56 Hollow pin 6 Conveying device 61 Belt conveyor 7 Pattern transfer device 70 Roller 72 Convex strip 73 Pattern transfer section

Claims

1. A method for patterning an extruded sheet, comprising extruding a mixture of cement-based or clay-based materials from the discharge port of an extruder, transporting it in the extrusion direction as an unhardened sheet, and transferring a pattern formed on the surface of the sheet by bringing the endless circumferential surface of a pattern transfer device installed downstream of the extruder into close contact with the surface of the sheet, wherein the die positioned above the discharge port of the extruder is provided with a downward-facing protrusion for forming the rough shape of the grooves extending in the extrusion direction and a flat portion for forming the main surface portion other than the grooves, while the circumferential surface of the pattern transfer device is provided with a protruding ridge that is continuous with the protrusion for forming the finished shape of the grooves and a pattern transfer portion for forming an uneven pattern on the main surface, wherein the width of the protruding ridge is set to be smaller than the width of the protrusion of the die, and the height of the circumferential surface of the protruding ridge at the lowest position of the circumferential surface of the pattern transfer device is the same as the height of the lower end surface of the protrusion of the die. A method for patterning an extruded sheet, characterized in that the height of the pattern transfer portion at the lowest position of the periphery of the pattern transfer device is lower than the height of the flat portion of the die, thereby moving the kneaded material forming the raw sheet in a direction that reduces the width of the groove portion by the pressure when the periphery of the pattern transfer device is brought into close contact with the raw sheet.

2. An extruded sheet manufacturing apparatus comprising: an extruder for forming an unhardened sheet by extruding a mixture of cement-based or clay-based materials from the discharge port of an extruder; a conveying device for conveying the sheet in the extrusion direction; and a pattern transfer device installed downstream of the extruder for transferring a pattern formed on the surface of the sheet by bringing its endless circumferential surface into close contact with the surface of the sheet, wherein the die positioned above the discharge port of the extruder is provided with a downward-facing protrusion for forming the rough shape of the grooves extending in the extrusion direction and a flat portion for forming the main surface portion other than the grooves, while the circumferential surface of the pattern transfer device is provided with a protruding ridge that forms the finished shape of the grooves continuous with the protrusion and a pattern transfer portion that continuously forms an uneven pattern on the main surface, wherein the width of the protruding ridge is set to be smaller than the width of the protrusion of the die, An extruded sheet manufacturing apparatus characterized in that the installation height of the pattern transfer device is set such that the height of the circumferential surface of the protrusion at the lowest position of the circumferential portion of the pattern transfer device is the same as the height of the lower end surface of the protrusion in the die, and the height of the pattern transfer portion at the lowest position of the circumferential portion of the pattern transfer device is lower than the height of the flat portion in the die.

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