JP2024004701A - Hydroponic panel and method for manufacturing hydroponic panel - Google Patents

Abstract

To provide a hydroponic panel that prevents a cultivation object from falling through a hole.SOLUTION: Provided is a hydroponic panel. In the panel, holes for the insertion of cultivation objects are provided to penetrate the panel vertically. Within each hole, an annular base face, and an upper side face extending from the outer edge of the base face to the top face, are provided. The base face and the upper side face are not parallel with each other.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hydroponic cultivation panel and a manufacturing method thereof.

Patent Document 1 discloses a hydroponic cultivation panel provided with a hole into which a cultivated product formed by planting a plant in a seedbed member is inserted.

Japanese Patent Application Publication No. 9-103203

In the panel of Patent Document 1, cultivated products are held in the holes by the frictional force between the seedbed member and the inner surface of the holes. However, in such a form, the frictional force tends to be insufficient, and in that case, there is a risk that the cultivated product may fall off.

The present invention has been made in view of these circumstances, and provides a hydroponic cultivation panel that can prevent cultivated plants from falling out of the holes.

According to the present invention, the following inventions are provided.
(1) A panel for hydroponic cultivation, wherein a hole into which a cultivated product is inserted is provided in the panel so as to pass vertically through the panel, and an annular base surface is provided in the hole. and an upper side surface extending from an outer edge of the base surface toward the upper surface, the base surface and the upper side surface being non-parallel.
(2) The panel according to (1), wherein the hole is provided with a lower side surface extending from the inner edge of the base surface toward the lower surface, and the base surface and the lower side surface The angle between the panels is between 20 and 90 degrees.
(3) The panel according to (2), wherein the lower side surface is a tapered surface that slopes so as to gradually expand in diameter toward the lower surface.
(4) A method for manufacturing a hydroponic cultivation panel, comprising a placement step, a molding step, and a post-processing step, and in the placement step, first and second molds that can be opened and closed with each other are opened. , a parison is arranged between the first and second molds, the first mold includes a first rib, the second mold includes a second rib, and the first and second ribs are opposed to each other. The diameter of the outer edge of the tip surface of the first rib is larger than the diameter of the outer edge of the tip surface of the second rib, and in the molding step, the With the parison in place, the first and second molds are closed and the first and second ribs are brought into contact with each other, thereby welding the opposing inner surfaces of the parison to each other to form a welded portion. A method in which a molded body is formed by molding into a panel shape, and in the post-processing step, the welded portion is removed to form a hole.
(5) The manufacturing method according to (4), wherein the welded portion is removed along the outer edge of the portion against which the tip end surface of the second rib is pressed.
(6) The method according to (4) or (5), wherein at least one of the tip end surface of the first rib and the tip end surface of the second rib is provided with an annular annular surface, and the inner side of the annular surface is provided with an annular annular surface. A recess is provided in the method.
(7) The method according to (6), wherein the annular surface is provided on both the distal end surface of the first rib and the distal end surface of the second rib, and the width of the annular surface of the first rib is The method is larger than the width of the annular surface of the second rib.

In the present invention, an annular base surface and an upper side surface non-parallel to the annular base surface are provided within the hole of the panel.
When the cultivated material is inserted into the hole in a compressed state, the cultivated material swells within the hole due to restoring force and is easily held by the base surface within the hole. For this reason, falling of cultivated products from the holes is suppressed.

FIG. 1A is a perspective view of the hydroponic cultivation panel 10, and FIG. 1B is an enlarged view of region B in FIG. 1A. 2A is a sectional view passing through the center of the panel 10 in the transverse direction of FIG. 1A, FIG. 2B is an enlarged view of region B in FIG. 2A, and FIG. 2C is a cross-sectional view of the panel 10 in FIG. 2B is a sectional view corresponding to FIG. 2B, showing a state where the panel 10 is floating on the nutrient solution 9. FIG. Note that FIG. 2B shows the structure of the panel 10 in detail, and in other figures, the panel 10 is shown in a simpler manner than in FIG. 2B. FIG. 3 is a sectional view showing a state after first and second resin sheets 5a and 5b are placed as a parison 5 between a first mold 21 and a second mold 22. FIG. Note that in FIGS. 3 to 10, for convenience of illustration, lines indicating parts deeper than the cross section are omitted. 4A is a cross-sectional view of the first rib 21a and second rib 22a taken out from FIG. 3, and FIG. 4B is a cross-sectional view of the ribs 21a and 22a of FIG. 4A butted against each other. FIG. 5 is a cross-sectional view showing a state after the resin sheets 5a, 5b are shaped using molds 21, 22 from the state shown in FIG. 4. FIG. 6 is a sectional view showing a state after the molds 21 and 22 are closed from the state shown in FIG. 5. FIG. 7A is a cross-sectional view of a portion near the ribs 21a and 22a extracted from FIG. 6, FIG. 7B shows a state in which the ribs 21a and 22a are removed from FIG. 7A, and FIG. The state after the welded portion 7 is removed along the outer edge 20h of the portion 20g against which the tip end surface 22g of the portion 22a is pressed is shown. FIGS. 8A to 8C correspond to FIGS. 7A to 7C, respectively, and show states in which the center positions C1 and C2 of the ribs 21a and 22a are shifted. 9A to 9C correspond to FIGS. 7A to 7C, respectively, and show comparative examples in which the outer edges 21h and 22h of the ribs 21a and 22a match. 10A, 10B and 10D correspond to FIGS. 9A to 9C, respectively, and in a comparative example in which the outer edges 21h and 22h of the ribs 21a and 22a are aligned, the center positions C1 and C2 of the ribs 21a and 22a are This shows the situation when a misalignment occurs. FIG. 10C is an enlarged view of region B in FIG. 10B, and FIG. 10E is an enlarged view of region E in FIG. 10D.

Embodiments of the present invention will be described below. Various features shown in the embodiments described below can be combined with each other. Further, the invention can be realized independently for each feature.

1. Hydroponic cultivation panel 10
The hydroponic cultivation panel 10 of one embodiment of the present invention shown in FIGS. 1 and 2 is used for hydroponic cultivation by being floated on a nutrient solution 9, as shown in FIG. 2C. The panel 10 is preferably constructed of a hollow resin molded body.

The panel 10 has a substantially rectangular shape, and has a short side dimension of, for example, 20 to 60 cm, a long side dimension of, for example, 50 to 100 cm, and a thickness of, for example, 20 to 40 mm. Specifically, the dimensions in the short side direction are, for example, 20, 25, 30, 35, 40, 45, 50, 55, and 60 cm, and are within the range between any two of the numerical values exemplified here. Good too. Specifically, the dimensions in the long side direction are, for example, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, and 100 cm, and the range is between any two of the numerical values exemplified here. It may be within. Specifically, the thickness of the panel 10 is, for example, 20, 25, 30, 35, 40 mm, and may be within a range between any two of the numerical values exemplified here. .

A hole 20 into which the cultivated product 4 is inserted is provided in the panel 10 so as to pass through the panel 10 in the vertical direction. It is preferable that the plant P is planted in the stopper 50 so that the cultivated product 4 can be easily held in the hole 20. It is preferable that the plug body 50 is elastically deformable and has water absorption properties, such as a sponge. The elastic force of the stopper 50 makes it possible to press the stopper 50 against the inner surface of the hole 20 and hold the cultivated product 4 in the hole 20.

The panel 10 is provided with a plurality of holes 20, and preferably the plurality of holes 20 are provided regularly. The distance between adjacent holes 20 is preferably 50 mm or more, for example. This interval is, for example, 50 to 150 mm, specifically, for example, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150 mm, and any of the numerical values exemplified here. It may be a range between the two or more than either.

The opening diameter D1 of the hole 20 on the upper surface 10a side is, for example, 20 to 40 mm, and the opening diameter D2 on the lower surface 10b side is, for example, 30 to 70 mm. In this specification, "opening diameter" and "diameter" mean a circular equivalent diameter.

Specifically, D1 is, for example, 20, 25, 30, 35, or 40 mm, and may be within a range between any two of the numerical values exemplified here. Specifically, D2 is, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70 mm, and may be within a range between any two of the numerical values exemplified here. D2/D1 is, for example, 1.1 to 3.0, specifically, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7. , 1.8, 1.9, 2.0, 2.5, 3.0, and may be within the range between any two of the numerical values exemplified here.

Inside the hole 20, an annular base surface 20a and an upper side surface 20i extending from an outer edge 20f of the base surface 20a toward the upper surface 10a are provided. The base surface 20a is provided so as to protrude toward the center of the hole 20 from the lower edge of the upper side surface 20i. Therefore, when the plug 50 is inserted into the hole 20 in a compressed state, the plug 50 expands within the hole due to the restoring force and is easily held by the base surface 20a inside the hole 20. Therefore, the plug body 50 is prevented from falling off from the hole 20. Note that instead of putting the plug 50 in a compressed state, a part of the plant P may be put in a compressed state and inserted into the hole 20. The explanation will be continued below, taking as an example the case where the plug body 50 is compressed and inserted into the hole 20.

The base surface 20a is preferably a flat surface, but may be a curved surface. The base surface 20a is preferably parallel to the top surface 10a of the panel 10, but may be non-parallel. The angle of the base surface 20a with respect to the upper surface 10a is, for example, -30 to 30 degrees, specifically, for example, -30, -25, -20, -15, -10, -5 , 0, 5, 10, 15, 20, 25, and 30 degrees, and may be within a range between any two of the numerical values exemplified here. Note that an angle is defined as positive when the inner edge 20b of the base surface 20a is inclined closer to the upper surface 10a than the outer edge 20f.

It is preferable that the upper side surface 20i is a tapered surface that slopes so as to gradually expand in diameter toward the upper surface 10a. The inclination angle γ of the upper side surface 20i with respect to the normal to the upper surface 10a is, for example, 0 to 30 degrees, preferably 5 to 20 degrees. Specifically, the inclination angle γ is, for example, 0, 5, 10, 15, 20, 25, or 30 degrees, and may be within a range between any two of the numerical values exemplified here. The base surface 20a and the upper side surface 20i are non-parallel, and the angle θ between the base surface 20a and the upper side surface 20i is, for example, 90 to 175 degrees, preferably 95 to 135 degrees. Specifically, the angle θ is, for example, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 155, 160, 165, 170, 175 degrees, where It may be within the range between any two of the numerical values exemplified.

The opening diameter of the hole 20 is the smallest at the inner edge 20b of the base surface 20a. The opening diameter D3 at the inner edge 20b is, for example, 15 to 35 mm, specifically, for example, 15, 20, 25, 30, 35 mm, and within the range between any two of the numerical values exemplified here. There may be. The diameter D4 of the outer edge 20f of the base surface 20a is, for example, 15.5 to 40 mm, specifically, for example, 15.5, 20, 25, 30, 35, and 40 mm, and any of the numerical values exemplified here. or within a range between the two. The width of the base surface 20a is, for example, 0.5 to 5 mm, preferably 1 to 3 mm. Specifically, this width is, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mm. Yes, it may be within the range between any two of the numerical values exemplified here. D1/D3 is, for example, 1.10 to 1.50, specifically, for example, 1.10, 1.15, 1.20, 1.25, 1.30, 1.35, 1.40. , 1.45, and 1.50, and may be within the range between any two of the numerical values exemplified here. The distance from the top surface 10a to the base surface 20a is, for example, 3 to 20 mm, specifically, for example, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20 mm, and is exemplified here. It may be within the range between any two of the above values.

Preferably, the hole 20 is provided with a lower side surface 20c extending from the inner edge 20b of the base surface 20a toward the lower surface 10b. The angle α between the base surface 20a and the lower side surface 20c is preferably 20 to 90 degrees, more preferably 35 to 75 degrees. Specifically, the angle α is, for example, 20, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 degrees, and is between any two of the numerical values exemplified here. may be within the range of In this case, since the angle α is a right angle or an acute angle, the protrusion 20d formed by the base surface 20a and the lower side surface 20c easily sinks into the plug body 50. Therefore, the plug body 50 is further prevented from falling off from the hole 20.

It is preferable that the lower side surface 20c is a tapered surface that slopes so as to gradually expand in diameter toward the lower surface 10b. Further, it is preferable that a tapered surface 20e having a smaller inclination angle with respect to the normal to the lower surface 10b than the lower side surface 20c is provided closer to the lower surface 10b than the lower side surface 20c. As a result, the volume of the hole 20 on the lower surface 10b side becomes larger than the inner edge 20b, making it easier to supply the nutrient solution and air to the plug body 50. Let β1 and β2 be the inclination angles of the lower side surface 20c and the tapered surface 20e with respect to the normal line of the lower surface 10b, β1-β2 is, for example, 15 to 45 degrees, and specifically, for example, 15, 20, 25 degrees. , 30, 35, 40, and 45 degrees, and may be within a range between any two of the numerical values exemplified here. β1 is, for example, 30 to 60 degrees, preferably 40 to 50 degrees. β2 is, for example, 5 to 25 degrees, preferably 10 to 20 degrees.

2. Method for manufacturing a panel 10 for hydroponic cultivation A method for manufacturing a panel 10 for hydroponic cultivation according to an embodiment of the present invention includes an arrangement step, a molding step, and a post-treatment step. Each step will be explained below.

2-1. Placement Step In the placement step, as shown in FIG. 3, the molds 21 and 22, which can be opened and closed with each other, are opened and the parison 5 is placed between the molds 21 and 22.

The first mold 21 includes a first rib 21a, and the second mold 22 includes a second rib 22a. The first rib 21a has a shape corresponding to the shape of a portion of the inner surface of the hole 20 that is closer to the upper surface 10a than the inner edge 20b, and the second rib 22a has a shape that corresponds to the shape of the portion of the inner surface of the hole 20 that is closer to the lower surface 10b than the inner edge 20b. It has a shape corresponding to the shape of the part. Therefore, a concave portion having a shape corresponding to the inner surface of the hole 20 is formed by the ribs 21a and 22a. The ribs 21a and 22a are arranged to face each other.

In this embodiment, as shown in FIG. 4, the diameter of the outer edge 21h of the tip surface 21g of the first rib 21a is larger than the diameter of the outer edge 22h of the tip surface 22g of the second rib 22a. By configuring the ribs 21a, 22a in this way, even if the center positions of the ribs 21a, 22a are misaligned, the welded portion 7 can be easily removed. This action and effect will be explained in more detail in "2-4. Comparison with Comparative Example". The tip surfaces 21g and 22g are preferably flat surfaces, but may be curved surfaces. The tip surfaces 21g and 22g are preferably perpendicular to the opening and closing direction of the molds 21 and 22 (left-right direction in FIG. 3), but may be non-perpendicular.

It is preferable that the first rib 21a is removably fixed to the first base 21b. The first rib 21a can be fixed by inserting the first mounting protrusion 21c into the first mounting hole 21e of the first base 21b. Since the first ribs 21a are removably fixed to the first base 21b, the number of first ribs 21a provided on the first mold 21 is variable. Therefore, the number of holes 20 can be easily changed by changing the number of first ribs 21a according to the specifications of the panel 10. The explanation here is the same for the second mold 22 ("first" is read as "second", and code "21" is read as "22").

The ribs 21a, 22a can be formed integrally with the bases 21b, 22b so as to be non-removable, but as in this embodiment, the ribs 21a, 22a are not integrated with the bases 21b, 22b. If the ribs 21a, 22a are not integrated with the bases 21b, 22b and are removable, the technical significance of applying the present invention is that the center positions of the ribs 21a, 22a tend to shift. This is particularly noticeable.

Parison 5 can be formed by extruding molten resin from an extrusion head (not shown). The parison 5 may be cylindrical or sheet-like. When the parison 5 is sheet-shaped, the parison 5 is composed of a pair of resin sheets 5a and 5b, for example. In this case, as shown in FIG. 3, resin sheets 5a and 5b are placed between the molds 21 and 22.

The resin constituting the parison 5 is preferably a thermoplastic resin such as polyolefin, and examples of the polyolefin include low density polyethylene, linear low density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof. It will be done.

2-2. Molding Process In the molding process, as shown in FIGS. 5 and 6, with the parison 5 disposed between the first mold 21 and the second mold 22, the molds 21 and 22 are closed, and the ribs 21a, 22a are butted against each other, the opposing inner surfaces of the parison 5 are welded together to form a welded part 7, and the parison 5 is formed into a panel shape to form a molded body 8. Examples of the molding method include blow molding, vacuum molding, and combinations thereof.

When the parison 5 is composed of resin sheets 5a and 5b, first, as shown in FIG. The resin sheet 5b is formed into a shape along the shaping surface 22f of the second mold 22 by vacuum suction using the second mold 22. Next, as shown in FIG. 6, the molds 21 and 22 are closed and the ribs 21a and 22a are brought into contact with each other, thereby welding the resin sheets 5a and 5b to each other to form a welded portion 7 and forming the resin sheet. A molded body 8 is formed by molding 5a and 5b into a panel shape.

2-3. Post-processing step In the post-processing step, as shown in FIG. 7, the welded portion 7 is removed from the molded body 8 to form the hole 20. The welded portion 7 may be removed within the molds 21, 22, or may be removed after the molds 21, 22 are opened and the molded body 8 is taken out.

The welded portion 7 is removed along the outer edge 20h of the portion 20g against which the tip end surface 22g of the second rib 22a is pressed, as shown in FIGS. 7B to 7C. As a result, a hole 20 having a shape corresponding to the outer edge 22h of the distal end surface 22g is formed. The welded portion 7 can be removed by cutting the welded portion 7 using a cutter or the like. The part 20g is a thin walled part where the parison 5 is crushed by the tip surfaces 21g and 22g, so the welded part 7 can be easily removed by cutting the welded part 7 along the part 20g. can do.

In the post-processing step, by performing various post-processing such as removing burrs 5c attached to the molded body 8, a desired panel 10 can be obtained as shown in FIG. 7C and FIGS. 1 and 2.

In the method of this embodiment, when shaping the resin sheets 5a, 5b, the ribs 21a, 22a first contact the resin sheets 5a, 5b, and then the other surfaces of the shaping surfaces 21f, 22f are Contact with the sheet. Therefore, the resin sheets 5a and 5b are hardly or not stretched at all in and around the areas where the tip surfaces 21g and 22g of the ribs 21a and 22a are in contact with each other, and are shaped by being stretched in other areas. . Therefore, the wall thickness of the side wall of the hole 20 tends to become large, and the wall thickness near the mating surfaces of the ribs 21a and 22a (near the inner edge 20b) tends to become particularly large. In addition, in the vicinity of the inner edge 20b, a protruding resin portion 20l (shown in FIG. 2B) that protrudes into the hollow part of the panel 10 is likely to be formed by the resin extruded when the ribs 21a and 22a are butted together, and from this point of view as well, the inner edge The wall thickness near 20b tends to be large. According to such a configuration, the strength near the inner edge 20b is increased, and the welding strength of the resin sheets 5a, 5b is also increased.

2-4. Comparison with Comparative Example In the configuration of the comparative example of the present invention, as shown in FIG. 9A, the center positions C1 and C2 of the ribs 21a and 22a are on the same straight line, and the outer edge 21h and the outer edge 22h are aligned. Then, in the post-processing step, as shown in FIGS. 9B to 9C, the welded portion 7 is removed along the outer edge 20h.

Such a configuration does not cause a problem if the center positions C1 and C2 of the ribs 21a and 22a are on the same straight line, but in reality, as shown in FIG. 10A, the center positions C1 and C2 of the ribs 21a and 22a are If the center position is shifted, the outer edges 21h and 22h may also be shifted, and as shown in FIGS. , 22g, a portion (non-thinned portion) 20j is provided. As shown in FIGS. 10D to 10E, when attempting to remove the welded portion 7 along the outer edge 20h, it is necessary to cut out the non-thin portion 20j, so the shape of the hole 20 may differ from the expected one. A problem arises in that it takes more time than usual to finish the cut surface 20k of the inner surface of the hole 20 so that it is smooth.

In this embodiment, such a problem is solved by making the diameter of the outer edge 21h of the tip surface 21g of the first rib 21a larger than the diameter of the outer edge 22h of the tip surface 22g of the second rib. In such a configuration, as shown in FIG. 8, when a deviation occurs in the center positions C1 and C2 of the ribs 21a and 22a, the outer edge 22h is prevented from protruding outside the outer edge 21h. , 22a are shifted, the welded portion 7 can be easily removed along the outer edge 20h because the entire outer edge 20h becomes a thin part.

Note that if the deviation between the center positions C1 and C2 of the ribs 21a and 22a is larger than the width between the outer edges 21h and 22h, the outer edges 22h may protrude from the outer edges 21h. It is preferable that the width between the ribs 21a and 22a is larger than the maximum value assumed as the deviation between the center positions C1 and C2 of the ribs 21a and 22a. For example, if the deviation between the center positions C1 and C2 of the ribs 21a and 22a is at most 1 mm, the width between the outer edges 21h and 22h may be, for example, 2 mm. The width between the outer edge 21h and the outer edge 22h corresponds to the width of the base surface 20a, and the width between the outer edge 21h and the outer edge 22h is, for example, 0.5 to 5 mm, preferably 1 to 3 mm. Specifically, this width is, for example, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 mm. Yes, and may be within the range between any two of the numerical values exemplified here.

As shown in FIG. 4, it is preferable that at least one of the distal end surface 21g of the first rib 21a and the distal end surface 22g of the second rib 22a is provided with annular annular surfaces 21i and 22i. In this case, the recesses 21j and 22j provided inside the annular surfaces 21i and 22i become the resin reservoir 23, and the resin extruded from the portion where the tip surfaces 21g and 22g are brought into contact can be stored in the resin reservoir 23.

It is preferable that the annular surfaces 21i and 22i are provided on both the distal end surface 21g of the first rib 21a and the distal end surface 22g of the second rib 22a. The width of the annular surface 21i is preferably larger than the width of the annular surface 22i. In this case, the diameter of the outer edge 21h of the distal end surface 21g of the first rib 21a is made larger than the diameter of the outer edge 22h of the distal end surface 22g of the second rib, and the resin reservoir 23 is easily enlarged.

4: Cultivated product 5: Parison 5a: Second resin sheet 5b: Second resin sheet 5c: Burr 7: Welded part 8: Molded body 9: Nutrient solution 10: Hydroponic cultivation panel 10a: Upper surface 10b: Lower surface 20: Hole 20a: Base surface 20b: Inner edge 20c: Lower side surface 20d: Protrusion 20e: Tapered surface 20f: Outer edge 20g: Part 20h: Outer edge 20i: Upper side surface 20j: Non-thin section 20k: Cut surface 20l: Protruding resin portion 21: First Mold 21a: First rib 21b: First base 21c: First mounting protrusion 21e: First mounting hole 21f: Shaping surface 21g: Tip surface 21h: Outer edge 21i: Annular surface 21j: Recess 22: Second mold 22a : Second rib 22b : Base 22c : Second mounting protrusion 22e : Second mounting hole 22f : Shaping surface 22g : Tip surface 22h : Outer edge 22i : Annular surface 22j : Recessed part 23 : Resin reservoir 50 : Plug body B : Area C1 : Center position C2 : Center position D1 : Opening diameter D2 : Opening diameter D3 : Opening diameter E : Area P : Plant α : Angle γ : Inclination angle θ : Angle

Claims (7)

A hydroponic cultivation panel,
A hole into which the cultivated product is inserted is provided in the panel so as to pass through the panel in the vertical direction,
An annular base surface and an upper side surface extending from an outer edge of the base surface toward the upper surface are provided in the hole,
The panel wherein the base surface and the upper side surface are non-parallel. The panel according to claim 1,
The hole is provided with a lower side surface extending from the inner edge of the base surface toward the lower surface,
The panel, wherein the angle between the base surface and the lower side surface is between 20 and 90 degrees. 3. The panel according to claim 2,
In the panel, the lower side surface is a tapered surface that slopes so as to gradually expand in diameter toward the lower surface. A method for manufacturing a hydroponic cultivation panel, the method comprising:
It includes a placement process, a molding process, and a post-processing process.
In the placement step, the first and second molds, which can be opened and closed with each other, are opened and the parison is placed between the first and second molds,
The first mold includes a first rib,
The second mold includes a second rib,
the first and second ribs are arranged to face each other,
The diameter of the outer edge of the tip surface of the first rib is larger than the diameter of the outer edge of the tip surface of the second rib,
In the molding step, the parison is placed between the first mold and the second mold, the first and second molds are closed, and the first and second ribs are brought into contact with each other. Welding the opposing inner surfaces of the parison to form a welded part, and forming the parison into a panel shape to form a molded body,
In the post-processing step, the welded portion is removed to form a hole. The manufacturing method according to claim 4,
In the method, the welded portion is removed along the outer edge of the portion where the tip end surface of the second rib is pressed. The method according to claim 4 or claim 5,
An annular annular surface is provided on at least one of the tip surface of the first rib and the tip surface of the second rib,
A recess is provided inside the annular surface. 7. The method according to claim 6,
The annular surface is provided on both the tip surface of the first rib and the tip surface of the second rib,
The width of the annular surface of the first rib is greater than the width of the annular surface of the second rib.