WO2015159420A1

WO2015159420A1 - Method for manufacturing hollow body from multilayer sheet and manufacturing system

Info

Publication number: WO2015159420A1
Application number: PCT/JP2014/061015
Authority: WO
Inventors: 真介後藤; 加藤　晴男; 淳一鵜飼; 浩司田村
Original assignee: 株式会社エムジーモールド
Priority date: 2014-04-18
Filing date: 2014-04-18
Publication date: 2015-10-22

Abstract

Provided are a manufacturing method and a manufacturing system for a hollow body in which adequate bonding strength can be obtained even when using multilayer sheets and draw-down during heating can be limited. A hollow body obtained from multilayer sheets is manufactured using multiple steps including: a high-inside-temperature double-sided heating step for disposing a pair of multilayer sheets next to each other so as to face each other in the vertical direction and heating from the outside using a first heat source while heating from the inside using a second heat source at a higher temperature than the first heat source; a one-sided heating step for heating only from the outside using the first heat source or a double-sided heating step for heating from the outside using the first heat source and heating from the inside using the second heat source at a temperature at or below the first heat source; and a molding step for molding the pair of multilayer sheets that has passed through the high-inside-temperature double-sided heating step and the one-sided heating step or the double-sided heating step.

Description

Manufacturing method and manufacturing system for hollow body made of multilayer sheet

The present invention relates to a method and system for manufacturing a hollow body made of a multilayer sheet.

In recent years, resin materials having a lightweight hollow structure have been used in place of conventional metal materials in electrical parts, machine parts, automobile components, etc., and their molded products and molding methods have been proposed. Has been.

As an example of a method for producing a resin molded product having a hollow structure, a twin composite molding method has been proposed (see Patent Document 1). In this molding method, for example, a pair of resin sheets are opposed to each other in the vertical direction, and the resin sheet is softened by heating with a heat source disposed outside (upper and lower) of these resin sheets, and then a pair of gold sheets Molding that forms a pair of resin sheets along the upper and lower molds by evacuating from the suction holes provided in the mold surface between the molds and injecting compressed air between the pair of resin sheets Is the law.

Incidentally, it has recently been proposed to use a multilayer sheet having a plurality of functions as the resin sheet constituting the hollow body. For example, a resin-made hollow air duct is used inside the interior panel of a vehicle such as an automobile to connect the air blowing port and the air intake port of an air conditioner or the like. A two-layer structure in which a foamed resin layer that prevents condensation due to temperature differences and abnormal noise due to contact with peripheral devices during vibration and a rigid resin layer with rigidity that can maintain its shape well The thing is proposed (refer patent document 2).

JP 2006-205831 A JP 2001-239824 A

However, when a hollow body made of a resin sheet having a multilayer structure as described above is to be manufactured by a conventional molding method, it is configured to heat from the outside of the resin sheet disposed oppositely, and thus is provided at the inner edge. In other words, the heating of the bonded portion, in other words, the melting of the surface layer portion of the opposing surface may be insufficient, and it is difficult to obtain sufficient bonding strength. In addition, because of the multilayer structure, the thermal conductivity of each layer of the resin sheet is different or the thickness increases, so the inner layer is not heated sufficiently, and the resin sheet has sufficient followability to the mold. It is difficult to obtain.

Also, in order to solve these problems, if the heating temperature is increased or the heating time is lengthened, the drawdown of the resin sheet increases. If the drawdown becomes large, the resin sheet arranged on the upper side cannot follow the upper mold surface of the mold, or the resin sheet arranged on the lower side may come into contact with the heat source during heating. Arise.

The present invention has been made in view of the circumstances as described above, and even when a multilayer sheet is used, a higher bonding strength can be obtained than before, and a hollow body that can suppress drawdown during heating can be produced. Methods and manufacturing systems are provided.

In order to solve the above-mentioned problems, a method for producing a hollow body made of a multilayer sheet according to the present invention includes a pair of multilayer sheets arranged side by side so as to face each other, heated from the outside by a first heat source, and inside To a second heat source, and a forming step for forming the pair of multilayer sheets that have undergone the heating step.

In another method for producing a hollow body comprising a multilayer sheet according to the present invention, a pair of the multilayer sheets are arranged side by side so as to face each other, heated from the outside by a first heat source, and heated from the inside by a second heat source. An inner high-temperature double-sided heating step in which heating is performed at a temperature higher than one heat source; a single-sided heating step in which the pair of multiphase sheets that have undergone the inner high-temperature double-sided heating step are heated from the outside only by the first heat source; And a molding step of molding the pair of multilayer sheets that have undergone the step.

Still another method for producing a hollow body comprising a multilayer sheet according to the present invention comprises a pair of multilayer sheets arranged side by side so as to face each other, heated from the outside by a first heat source and from the inside by a second heat source. An inner high-temperature double-sided heating step in which heating is performed at a temperature higher than one heat source; and the pair of multilayer sheets that have undergone the inner high-temperature double-sided heating step are heated from the outside by the first heat source and from the inside by the second heat source. It includes a double-sided heating step of heating at a temperature of 1 heat source or less and a forming step of forming the pair of multilayer sheets that have undergone the double-sided heating step.

In the above configuration, in the one-side heating step, the second heat source can be retracted to a position that is laterally removed from the position where the multilayer sheet faces.

In the heating process, the inner high-temperature double-sided heating process, and the double-sided heating process, the second heat source can be disposed closer to the multilayer sheet disposed on the lower side of the pair of multilayer sheets.

The hollow body manufacturing system according to the present invention includes a sheet holding mechanism that arranges a pair of multilayer sheets so as to face each other, a first heat source that heats outer surfaces of the pair of multilayer sheets, and the pair of pairs. A heating device having a second heat source for heating the inner surface of the multilayer sheet, a transport mechanism for transporting the pair of multilayer sheets, a molding device having a pair of molding dies, and a control unit, An inner high-temperature double-sided heating process in which the first heat source heats the outer surfaces of the pair of multilayer sheets and the second heat source heats the inner surfaces of the pair of multilayer sheets at a higher temperature than the first heat source; Heating only the outer surfaces of the pair of multilayer sheets, or causing the first heat source to heat the outer surfaces of the pair of multilayer sheets and the second heat source to the pair of multilayer sheets. Double-sided heat treatment for heating the inner surface of the sheet at a temperature lower than the first heat source, and conveying the pair of multilayer sheets heated by the first heat source and the second heat source to the conveying mechanism between the pair of molds. And a forming process for causing the forming apparatus to form the pair of multilayer sheets transported by the transport mechanism by the pair of forming dies.

The manufacturing system includes a retracting mechanism for retracting the second heat source from a position where the pair of multilayer sheets face each other to a position deviated laterally, and the control unit is configured to perform the one-side heating process, In the heat treatment, the retracting mechanism can be configured to retract the second heat source to a position off the side.

In the manufacturing system, the second heat source may be arranged closer to the multilayer sheet disposed on the lower side of the pair of multilayer sheets.

According to the above-described method and system for producing a hollow body made of a multilayer sheet, the bonding strength of the edges of the pair of multilayer sheets can be improved, and the drawdown during heating can be suppressed.

The schematic side view which illustrates the manufacturing system of the hollow body which consists of a multilayer sheet concerning the present invention It is AA sectional drawing of FIG. 1, Comprising: The schematic which shows an internal high temperature double-sided heating process Schematic showing a single-sided heating process in which the second heat source is in the retracted position in the manufacturing system of FIG. FIG. 1 is a schematic view showing a state in which a pair of two-layer sheets are arranged in a mold in the manufacturing system of FIG. FIG. 1 is a schematic diagram showing a state in which the manufacturing system of FIG. FIG. 1 is a schematic view showing a state where the mold is clamped and compressed in the manufacturing system of FIG. 1. FIG. 1 is a schematic view showing a state in which the mold is opened in the manufacturing system of FIG. Sectional drawing which shows the hollow molded product shape | molded with the manufacturing system of FIG. The block diagram which shows the electrical constitution of the manufacturing system of FIG. The flowchart which shows the process which a control part performs in the manufacturing system of FIG.

In the method for producing a hollow body composed of the multilayer sheet of the present invention, for example, from both the outside and inside both sides of the multilayer sheet opposed in the vertical direction, from the outside by the first heat source, and from the inside by the second heat source, Since heating is performed, the entire pair of multilayer sheets is heated to a good state in a short time.

Here, if a pair of multilayer sheets is heated slowly from both sides to the temperature required to form and weld the hollow body, there is a concern that the sheets become too soft and the drawdown increases. Further, if the heating temperature is set low in order to suppress the drawdown, there is a concern that the transferability at the time of molding and the bonding strength are insufficient.

However, as described above, when a process / process (inner high-temperature double-sided heating process / process) is performed in which heating from the inside by the second heat source is performed at a higher temperature and in a shorter time than heating from the outside by the first heat source, In particular, since the surface layer portion is heated so as to be baked by the second heat source, the bonded portion is in a good molten state, and high bonding strength can be obtained. Further, the inner side of the inner surface layer portion is not heated too much, and a certain degree of hardness is maintained, so that drawdown can be suppressed.

On the other hand, in addition to the inside high-temperature double-sided heating process (process), the single-sided heating process (process) that heats only from the outside, or the double-sided heating process (process) that heats from the outside and heats from the inside to below the outside In addition, since the entire sheet can be heated, transferability and shaping at the time of molding can be secured.

According to such a configuration, the entire sheet can be heated in a short time as compared to a configuration in which the entire sheet is heated from the outside or slowly from both sides over time, and the inner side from the inner surface layer portion is the sheet. Since it is not overheated until just before the whole is heated, and a certain degree of hardness can be maintained during heating, the drawdown of the multilayer sheet during heating can be reduced. In addition, since the inner joint portion can be surely brought into a good molten state, the joint strength can be increased as compared with the conventional case.

In the above configuration, when the single-sided heating step (processing) is performed, the inner second heat source can be retracted to a position deviated laterally from the position where the multilayer sheet faces. This prevents the multilayer sheet from coming into contact with the second heat source disposed in a narrow space between the pair of multilayer sheets even when the multilayer sheet disposed on the upper side of the pair of multilayer sheets is drawn down. Can increase the safety of the device.

Further, in the heating step (treatment), the inner high-temperature double-sided heating step (treatment) and the double-sided heating step (treatment), the inner second heat source may be arranged near the multilayer sheet arranged on the lower side of the pair of multilayer sheets. it can.

In general, since heat generated from the heat source flows upward, in order to bring the multilayer sheet disposed on the upper side of the second heat source and the multilayer sheet disposed on the lower side into a similar heating state, The heat source is preferably disposed near the multilayer sheet disposed on the lower side. Moreover, when doing in this way, even when the multilayer sheet arrange | positioned at the upper side draws down, the risk that the multilayer sheet contacts a 2nd heat source can be reduced.

Hereinafter, with reference to FIG. 1 to FIG. 10, a case where the manufacturing method and manufacturing system of a hollow body made of a multilayer sheet according to the present invention is applied to a two-layer duct mounted on a vehicle will be described.

FIG. 8 is a cross-sectional view showing a two-layer duct 10 (an example of a hollow body). This two-layer duct 10 has a two-layer structure of an outer layer 10A made of foamed resin and an inner layer 10B made of hard resin laminated inside the outer layer 10A. The two-layer duct 10 is formed in a cylindrical body having an air flow passage 10C formed therein.

The two-layer duct 10 is manufactured from a two-layer sheet 11. The two-layer sheet 11 is heat-insulating, for example, on one surface side of a foamed resin sheet 12 (constituting the outer layer 10A) such as foamed polyethylene or foamed polypropylene. The two-layer sheet 11 is more rigid than the foamed resin sheet 12 and preferably has a shape as a duct. For example, a hard resin layer 13 such as polyethylene or polypropylene (which constitutes the inner layer 10B) is laminated.

More specifically, the two-layer sheet 11 is obtained by laminating a hard resin layer 13 made of polypropylene having higher rigidity than the foamed resin sheet 12 on one surface side of the foamed resin sheet 12 made of polypropylene and expanded 25 to 40 times. It is composed of The thickness of the foamed resin sheet 12 is greater than the thickness of the hard resin layer 13. For example, the thickness of the foamed resin sheet 12 is set to 5 mm, and the thickness of the hard resin layer 13 is set to about 0.2 to 0.4 mm. This two-layer sheet 11 is manufactured in advance and wound into a roll.

It should be noted that the combination of the resin types of these layers can be either the same type or different types. For example, the heat insulating layer (foamed resin sheet 12) can be the inner layer 10B, and the rigid layer (hard resin layer 13) can be the outer layer 10A.

FIG. 1 is a schematic view showing the entire manufacturing system 20 of the two-layer duct 10 described above, and FIG. 9 is a block diagram showing an electrical configuration of the manufacturing system 20. The manufacturing system 20 holds the two-layer sheet 11. Sheet holding mechanism 21, transport mechanism 24 for transporting the held two-layer sheet 11, heating device 30 for heating the transported two-layer sheet 11, and molding for molding the heated two-layer sheet 11 The apparatus 40, the cutter 46, the control part 50 which controls each part, the operation part 53, and the display part 54 are provided. In this manufacturing system 20, the double-layer sheet 11 is conveyed from the left side to the right side in FIG. In the following description, the right side of FIG.

The sheet holding mechanism 21 of the manufacturing system 20 includes a number of clamps 22 each having a compression spring 22B attached between a pair of clamping

plates

22A and 22A, and a guide 23. As shown in FIG. 2, the clamp 22 clamps the edge of the two-layer sheet 11 in the pressed state, and in the released state, the pair of sandwiching

plates

22A and 22A are separated by the compression spring 22B. The sheet 11 can be arranged between them, or can be pulled out between them. The clamping plate 22 </ b> A located on the lower side of the multiple clamps 22 is configured as a part of two pairs of transport chains 25 described later. The guide 23 provided along the transport chain 25 is pressed or released.

The transport mechanism 24 includes two pairs of annular transport chains 25, a sprocket 26 that is provided behind the heating device 30 and in front of the molding device 40 and hangs the transport chain 25, and a drive motor (not shown) that drives the sprocket 26 to rotate. It has. The transport chain 25 is disposed outside the both edges of the two-

layer sheets

11 and 11 that extend in the direction along the transport direction (the left-right direction in FIG. 1) of the two-layer sheet 11 and face the top and bottom. The held two-layer sheet 11 can be transported along the transport direction. The transport chain 25 is movable by driving a drive motor. In addition, the transport chain 25 is configured to transport the double-layer sheet 11 from the rear of the heating device 30 to the front of the molding device 40, and then change the direction to return to the rear of the heating device 30.

The heating device 30 includes a heating chamber 31 that accommodates a first heat source 32 and a second heat source 33 to be described later. Inside the heating chamber 31, the two-layer sheet 11 held by the clamp 22 is transported. 25 is carried in and passed through.

The heating chamber 31 includes a first heating unit 34 and a second heating unit 35 that are provided side by side in the conveyance direction of the double-layer sheet 11 (the left-right direction in FIG. 1). The first heating unit 34 is located between the pair of

first heat sources

32, 32 located outside the pair of two-

layer sheets

11, 11 that are vertically opposed to each other and the pair of two-layer sheets 11, 11 (inside). And a second heat source 33 located therein. More specifically, as shown in FIGS. 1 and 2, a first heat source 32A disposed above the upper two-layer sheet 11A and a first heat source disposed below the lower two-layer sheet 11B. 32B and a second heat source 33 disposed between the upper two-layer sheet 11A and the lower two-layer sheet 11B. The second heating unit includes only a pair of

first heat sources

32A and 32B located above and below the pair of two-

layer sheets

11 and 11.

The first heat source 32 is composed of a plurality of block-shaped medium-wavelength infrared heaters, and these infrared heaters are arranged side by side in a plurality of rows so as to face each other vertically. The plurality of infrared heaters can be individually adjusted in output. The heating irradiation distance from each first heat source 32 to the pair of two-

layer sheets

11, 11 conveyed between the upper and lower

first heat sources

32, 32 is the upper two layers from the upper first heat source 32 </ b> A. The distance to the sheet 11A is set to be shorter than the distance from the lower first heat source 32B to the lower two-layer sheet 11B.

For example, the heating irradiation distance from the first heat source 32 to the two-layer sheet 11 is 150 mm on the upper side and 250 mm on the lower side. The surface temperature of the first heat source 32 is set to about 400 degrees.

On the other hand, the second heat source 33 is preferably one that quickly rises in temperature after the power is turned on, and a carbon heater, a halogen heater, or the like can be used. Specifically, a plurality of rod-shaped carbon heaters are arranged side by side along the conveying direction of the double-layer sheet 11 (left-right direction in FIG. 1). The plurality of carbon heaters can be individually adjusted in output.

The second heat source 33 is disposed near the sheet 11B disposed on the lower side of the pair of two-

layer sheets

11A and 11B. For example, the heating irradiation distance from the second heat source 33 to the two-

layer sheets

11 and 11 is 150 mm on the upper side and 50 mm on the lower side (see FIG. 2). The surface temperature of the second heat source 33 is set to about 1000 degrees.

The upper surface of the lower first heat source 32B and the upper surface of the second heat source 33 of the upper and lower first heat sources 32 and the upper surface of the second heat source 33 are prevented from contacting the heat source of the two-layer sheet 11 when the two-layer sheet 11 is drawn down. A safety net (not shown) is provided.

The second heat source 33 is provided with a retraction mechanism 36. The retraction mechanism 36 is configured to move the second heat source 33 in the horizontal direction from the conveyance path of the two-layer sheet 11 after the second heat source 33 is heated by the second heat source 33 and the power is turned off. , Away from the side of the two-layer sheet 11. The second heat source 33 is integrally connected to an opening / closing door 31B that closes an opening 31A provided in the heating chamber 31, and is opened / closed by a driving device such as an air cylinder (not shown) connected to the opening / closing door 31B. At the same time, it can be retracted from the opening 31A to the outside of the heating chamber 31 (see FIG. 3).

Also, a draw-down detection sensor (not shown) is installed on the upper surface side of the first heat source 32B and the second heat source 33 on the lower side, and the two-

layer sheets

11B and 11A are likely to draw down by heating and come into contact with the heat source. When it becomes, it is set so that the power source of the heat source is automatically turned off.

The forming apparatus 40 has a pair of upper and lower vacuum forming dies 41 and 42. Both vacuum forming dies 41, 42 have

concave mold surfaces

41A, 42A capable of shaping the duct shape in the double-layer sheet 11, and these

mold surfaces

41A, 42A are for vacuuming (not shown). A plurality of suction holes are formed. Further, an air hole (not shown) communicating from the outside is provided between the pair of

mold surfaces

41A and 42A, and compressed air can be press-fitted into the

molds

41 and 42 in a closed state through the air holes.

As shown in FIG. 9, the control unit 50 includes a central processing unit (hereinafter referred to as CPU) 51 and a memory 52. The memory 52 includes, for example, a ROM, a RAM, and the like, and various programs such as a program for executing each manufacturing process described later are stored in the ROM. The CPU 51 controls each part of the manufacturing apparatus 20 according to a program read from the ROM. In addition to the ROM and RAM, the storage medium storing the various programs may be a non-volatile memory such as a CD-ROM, a hard disk device, or a flash memory.

The operation unit 53 has a plurality of buttons, and various input operations and setting operations can be performed by the user. The display unit 54 includes a liquid crystal display, a lamp, and the like, and can display various setting screens and operation states of the apparatus.

Next, a method for manufacturing the two-layer duct 10 will be described. FIG. 10 is a flowchart showing a process performed by the control unit 50 for a first region to be described later of the two-layer duct 10 of the present embodiment.

First, the pair of two-

layer sheets

11 and 11 are pulled out from the pair of winding

rolls

27 and 27 with the hard resin layers 13 and 13 facing each other in the up-and-down direction, and are vertically moved through the pair of

delivery rollers

28 and 28. Send out in parallel in the direction. Further, both edge portions along the conveying direction of the two-

layer sheets

11 and 11 are inserted between the clamping

plates

22A and 22A of the clamp 22 in the released state, and the conveying chain 25 is slightly advanced to be clamped between the clamping

plates

22A and 22A. . Thereby, a pair of two-layer sheet | seats 11 and 11 are each hold | maintained in the tension | tensile_strength state facing up and down.

The two-

layer sheets

11 and 11 are set so as to be intermittently sent out for each region formed in a forming step described later. Hereinafter, for the sake of explanation, the first region, the second region, and the third region will be referred to in order from the front side (the right side in FIG. 1) in the conveyance direction of the double-layer sheet 11.

When the user presses the manufacturing start button of the operation unit 53, the control unit 50 performs the process shown in FIG.

The control unit 50 activates the transport mechanism 24 to transfer the two-

layer sheets

11 and 11 held by the clamp 22 between the

first heat sources

32 and 32 and the second heat source 33 in the heating chamber 31, respectively. It is conveyed by. Further, the second heat source 33 is inserted into the heating chamber 31 through the opening 31A (S1).

In the heating chamber 31, the

first heat sources

32A and 32B are always on, and the entire heating chamber 31 has a temperature atmosphere of about 400 degrees. After the two-

layer sheets

11 and 11 are carried into the heating chamber 31 and the entire first region reaches the first heating unit 34 (between the first heat source 32 and the second heat source 33), the two-

layer sheet

11 and 11 are temporarily stopped, and the second heat source 33 is turned on for 6 seconds (inner high temperature double-sided heating step) (S2). The surface layer portion inside the two-layer sheet 11, 11 (hard resin layer 13) is heated so as to be baked by the high-temperature second heat source 33, and is in a good molten state.

Thereafter, the second heat source 33 is turned off (S3), the retracting mechanism 36 is activated, and the second heat source 33 is separated from the two-

layer sheets

11 and 11 from the opening 31A of the heating chamber 31. Retreating outside (see FIG. 3) (S4). In addition, the heating by the 1st heat source 32 is continued (one side heating process).

After the entire first region of the two-

layer sheets

11, 11 reaches the first heating unit 34, the time required for the molding process described later (21 seconds in the present embodiment) has elapsed, and then the two-

layer sheets

11, 11 Is again transported forward by the transport chain 25 (S5). As a result, the first region of the two-

layer sheets

11, 11 proceeds to the second heating unit 35, and the second region is carried into the first heating unit 34. Then, the first region is made to reach the second heating unit 35, and the second region is made to reach the first heating unit 34, and then temporarily stopped at that position (21 seconds). Accordingly, the first region is further heated only from the outer

first heat sources

32A and 32B (one-side heating step).

In addition, the magnitude | size of the drawdown of the two-layer sheet 11 in these heating processes can be reduced greatly compared with the structure heated only from the outside or the same conditions from the outside and the inside.

In the heating device 30, the second heat source 33 is set to be turned off and at the same time retracted to the side of the two-layer sheet 11. Therefore, even when the two-layer sheet 11 is drawn down, the second heat source 33 is turned off. It does not contact the heat source 33 and is excellent in safety. In addition, since the two-layer sheet 11 and the first heat source 32 below are sufficiently separated from each other, there is a low possibility that they will come into contact even when drawn down.

It should be noted that the time and temperature when the inner high-temperature double-sided heating step and the single-sided heating step are performed are not particularly defined, and can be arbitrarily set according to the constituent material of the sheet, the thickness of each layer, and the like.

Next, the first region of the pair of two-

layer sheets

11 and 11 that has been heated by the heating device 30 through the heating process is conveyed to the forming device 40 (S6). When the first region is reached between the vacuum forming dies 41 and 42 of the forming apparatus 40, the two-

layer sheets

11 and 11 are temporarily stopped. At this time, the second region has reached the second heating unit 35 and the third region has reached the first heating unit 34.

As shown in FIG. 4, the forming apparatus 40 is activated for the first region of the two-

layer sheets

11, 11 that are conveyed and stopped between the pair of open vacuum forming dies 41, 42, and then vacuumed. The

molds

41 and 42 are clamped (S7). Then, the parting lines of the vacuum forming dies 41 and 42 are first abutted against the two-

layer sheets

11 and 11, and between the upper die 41 and the upper sheet 11 </ b> A, and between the lower die 42 and the lower sheet 11 </ b> B. A sealed space is formed between each. In this state, when vacuum suction is performed from a plurality of suction holes provided in the mold surfaces 41A and 42A, the air in the sealed space is discharged, and the two-

layer sheets

11 and 11 warmed by the heating process follow the mold surface. Suction into shape (see FIG. 5).

At this time, even if the two-

layer sheets

11 and 11 are drawn down, the parting lines of the

molds

41 and 42 come into contact with the surfaces of the two-

layer sheets

11 and 11 to form a sealed space. Therefore, the air in the sealed space is discharged and the two-layer sheets 11 can be brought into close contact with the mold surfaces 41A and 42A.

Then, while maintaining the vacuum suction state, the parting lines of the pair of molding dies 41 and 42 are brought closer to each other, but they are pressed against each other and clamped. By the mold clamping, the shapes of the molding dies 41 and 42 are formed on the two-

layer sheets

11 and 11, and the edge portions of both the two-

layer sheets

11 and 11 are joined.

Finally, gas is blown from the air nozzle 45 (blow needles φ6 to φ12) between the pair of the two-

layer sheets

11 and 11 arranged in the mold surfaces of the molds 41 and 42 (0.4 Mpa to 0). .7 Mpa) to inject compressed air. Arbitrary gases, such as air, nitrogen, a carbon dioxide gas, are used as gas. Thereby, the two-

layer sheets

11 and 11 are reliably pressed against the

molds

41 and 42 and cooled (see FIG. 6).

When the molding by the molding apparatus 40 is completed in this way and the first region of the pair of two-

layer sheets

11 and 11 to which the edge portions are welded is cooled (S8), the pair of molding dies 41 and 42 are removed. Open (S9). After the above forming process is completed, when the transport chain 25 is driven again and the first region of the two-

layer sheets

11 and 11 is sent out from the forming device 40 (S10), the first region is removed from the clamp 22. Is done. Further, the second region of the two-

layer sheets

11 and 11 is advanced between the pair of

molds

41 and 42. Then, after the molding completion portion (first region) of the fed two-

layer sheets

11 and 11 is separated from the second region by the cutter 46 (S11), excess peripheral portions and burrs are removed with a three-dimensional Thomson blade. Trimming is performed to obtain a two-layer duct 10 (see FIG. 8) (S12).

According to such a two-layer duct manufacturing method, the entire sheet can be warmed up in a short time as compared to the conventional configuration in which the entire sheet is warmed up only from the outside as in the prior art. The inner side of the surface layer of the surface) is not overheated until just before the entire sheet is heated, and a certain degree of hardness can be maintained during heating, so that the drawdown of the two-layer sheet during heating can be reduced. In addition, since the inner joint portion can be surely brought into a good molten state, sufficient joint strength can be obtained as compared with the conventional case.

Further, according to the manufacturing apparatus 20 described above, in the heating apparatus 30, the second heat source 33 is set to be turned off, and at the same time, retracted to a position away from the side of the two-layer sheet 11, Even when the two-layer sheet 11 is drawn down, it does not come into contact with the second heat source 33 and is excellent in safety. In addition, since the two-layer sheet 11 and the first heat source 32 below are sufficiently separated from each other, the possibility that they are in contact with each other even when drawn down is safe.

The present invention is not limited to the embodiment described above according to the drawings, and for example, the following embodiment is also included in the technical scope of the present invention.

(1) In the above embodiment, the pair of sheets has a two-layer structure including a foamed resin sheet having heat insulation and a hard resin layer having rigidity, and both are made of polypropylene. Polyethylene or the like can also be used. Different types of materials can also be combined. Further, contrary to the above-described embodiment, a configuration may be adopted in which a rigid layer is disposed on the outer layer side and a heat insulating layer is disposed on the inner layer side.

(2) In addition, the sheet is not limited to a two-layer structure, and may have three or more layers.

(3) In the above embodiment, the medium wavelength infrared heater is used as the first heat source. However, other types of heaters such as a far infrared heater may be used.

(4) In the above embodiment, the carbon heater is used as the second heat source. However, other heaters that rise quickly can be used. For example, a halogen heater using tungsten as a filament can be used.

(5) In the above embodiment, the single-sided heating step is performed after the inner high-temperature double-sided heating step, but the double-sided heating step can be performed instead of the single-sided processing step.

(6) The second heat source may be a fixed configuration that does not retract.

(7) The irradiation distance from the first heat source and the second heat source to the two-layer sheet is not limited to the above embodiment, and can be arbitrarily set depending on the material and thickness of the two-layer sheet. Moreover, it can also be set as the structure which sets the irradiation distance of an upper side and a lower side equally.

(8) The transport mechanism and the holding mechanism are not limited to the above embodiment.

(9) In the above embodiment, the second heat source 33 and the open / close door 31B are integrally connected and the open / close door 31B is retracted from the heating chamber 31. However, the second heat source 33 and the open / close door 31B are separately provided. The opening / closing door 31B may be configured to have only the opening / closing function of the opening 31A, and the second heat source 33 may be directly provided with a retraction mechanism.

(10) In the above-described embodiment, the control unit 50 is configured to execute each step shown in FIG. 10 by one CPU 51. However, the present invention is not limited to this, and the control unit 50 is configured by a plurality of CPUs. A configuration for executing the steps, a configuration for executing each step shown in the figure only by a hardware circuit such as ASIC (Application Specific Integrated Circuit), or a configuration for executing each step shown in the figure by the CPU and the hardware circuit. it can.

(11) In the above embodiment, the control unit 50 is configured to execute each process. However, a configuration in which the user performs the operation by himself / herself may be employed.

10 Double-layer duct 11 Double-layer sheet (multi-layer sheet)
DESCRIPTION OF SYMBOLS 12 Outer layer 13 Inner layer 20 Manufacturing system 21 Sheet holding mechanism 24 Conveyance mechanism 30 Heating device 32 First heat source 33 Second heat source 36 Retraction mechanism 40 Molding device 41 Upper die 42 Lower die 50 Control unit

Claims

A method for producing a hollow body made of a multilayer sheet, wherein the pair of multilayer sheets are arranged side by side so as to face each other, and heating is performed from the outside by a first heat source and from the inside by a second heat source; and And a forming step of forming the pair of multilayer sheets that have undergone the heating step.
A method for producing a hollow body made of a multilayer sheet, wherein a pair of multilayer sheets are arranged so as to face each other, heated from the outside by a first heat source, and heated from the inside by a second heat source to a temperature higher than that of the first heat source. An inner high-temperature double-sided heating step for heating at a time, a single-sided heating step for heating the pair of multilayer sheets that have undergone the inner-side high-temperature double-sided heating step by the first heat source only from the outside, The manufacturing method of the hollow body which consists of a multilayer sheet | seat characterized by including the formation process of shape | molding a multilayer sheet | seat.
A method for producing a hollow body made of a multilayer sheet, wherein a pair of multilayer sheets are arranged so as to face each other, heated from the outside by a first heat source, and heated from the inside by a second heat source to a temperature higher than that of the first heat source. An inner high-temperature double-sided heating step in which heating is performed at a temperature, and the pair of multilayer sheets that have undergone the inner-side high-temperature double-sided heating step are heated from the outside by the first heat source and at a temperature lower than the first heat source by the second heat source from the inside A method for producing a hollow body comprising a multilayer sheet, comprising: a double-sided heating step in which heating is performed, and a molding step in which the pair of multilayer sheets that have undergone the double-sided heating step are molded.
The method for producing a hollow body made of a multilayer sheet according to claim 2, wherein, in the one-side heating step, the second heat source is retracted to a position deviated laterally from a position where the pair of multilayer sheets face each other.
5. The method according to claim 1, wherein, in the heating step, the inner high-temperature double-side heating step, and the double-side heating step, the second heat source is disposed closer to the multilayer sheet disposed on the lower side of the pair of multilayer sheets. A method for producing a hollow body comprising a multilayer sheet according to one item.
A hollow body manufacturing system comprising a multilayer sheet, a sheet holding mechanism for arranging a pair of multilayer sheets so as to face each other in the vertical direction, a first heat source for heating the outer surfaces of the pair of multilayer sheets, and the pair A heating device having a second heat source for heating the inner surface of the multilayer sheet, a transport mechanism for transporting the pair of multilayer sheets, a molding device having a pair of molding dies, and a control unit, An inner high-temperature double-sided heat treatment for causing the first heat source to heat the outer surfaces of the pair of multilayer sheets and causing the second heat source to heat the inner surfaces of the pair of multilayer sheets at a higher temperature than the first heat source; Heating the outer surfaces of the pair of multilayer sheets, or heating the outer surfaces of the pair of multilayer sheets to the first heat source and the pair of heat sources to the second heat source. A double-sided heating process for heating the inner surface of the layer sheet at a temperature equal to or lower than the first heat source, and the pair of multilayer sheets heated by the first heat source and the second heat source on the transport mechanism between the pair of molds. A hollow made of a multilayer sheet characterized by having a configuration in which a conveyance process to convey and a molding process in which the pair of multilayer sheets conveyed by the conveyance mechanism to the molding apparatus are molded by the pair of molds are performed. Body manufacturing system.
And a retraction mechanism for retreating the second heat source from a position where the pair of multi-layer sheets face each other to a side position, and the control unit is configured to perform the one-side heat treatment. Then, the hollow body manufacturing system according to claim 6, wherein the retracting mechanism retracts the second heat source to a position off the side.
The system for producing a hollow body made of a multilayer sheet according to claim 6 or 7, wherein the second heat source is disposed near the multilayer sheet disposed on the lower side of the pair of multilayer sheets.