JP4292858B2 - Material blowing method in rotary molding machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a molding machine for molding a molded product such as a hollow container, and in particular, a plurality of molds are arranged in an annular shape on a base, and the molds are fed in an annular shape along with the rotation of the base. The present invention relates to a material blowing method in a rotary molding machine that blows air into a material in a mold to form a molded product having a predetermined shape.
[0002]
[Prior art]
There is known a rotary molding machine in which a plurality of molds are annularly arranged on a base, and a molded product having a predetermined shape is molded while rotating the mold together with the base. Such a rotary type molding machine is used, for example, in a molding method of a molded product such as a hollow container, and in particular, a parison extruded from a die head is received by a pair of split molds, and the mold is closed. It is generally used for blow molding in which air is blown and then the mold is opened to take out a molded product (see, for example, Patent Document 1, Patent Document 2, and Patent Document 3).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 52-58671 (see detailed description of the invention in the specification)
[Patent Document 2]
JP 2000-296826 A (see column [0020] in the specification)
[Patent Document 3]
Japanese Unexamined Patent Publication No. 2000-313056 (refer to the detailed description of the invention in the specification)
[0004]
In such a rotary blow molding machine, a plurality of split molds are fixed to an annular rail, and each split mold is continuously opened and closed while moving in a ring, and the molded product is rotated while the annular rail is rotated once. The blow molding is completed by performing the process up to take-out. A rotary blow molding machine can mold a molded product with a large number of annular molds, for example, 8 to 14 split molds, so that it can be efficiently molded when mass-producing the same type of molded product. There is an advantage that can be.
[0005]
FIG. 9A is a front view of a main part of a rotary blow molding machine for forming a hollow container.
The rotary blow molding machine includes a molding unit 6 in which a plurality (eight in this embodiment) of molds 220 are arranged at equal intervals on the same circumference, and a predetermined position (station (1)) on the molding unit 6. ), The die head 5 for supplying the parison (material) P from the discharge port 5a, and the molded product take-out portion 8 for taking out the molded product from the mold 220 at a predetermined position (station (7)).
The molding unit 6 is configured by attaching the mold 220 to the annular base 61 at an equal interval, and the mold 220 and the base 61 are driven by the rotation driving unit 65 provided in the center of the base 61 as shown in FIG. Rotates in the clockwise direction.
[0006]
In the above rotary blow molding machine, the parison P is supplied from the die head 5 at the station (1), and the upper mold and the lower mold constituting the mold 220 are closed while moving from the station (1) to (2). At station (3), a blow nozzle 222 is inserted into the mold 220 from the radial direction of the rotation circumference of the base 61 as shown in FIG. 9B, and air is blown into the parison P. It is. By this air blowing, the parison P swells into a shape corresponding to the cavity 221 and is cooled while moving from the station (3) to (6), and is taken out by the molded product take-out section 8 at the station (7).
[0007]
By the way, in the conventional rotary blow molding machine described above, it is required to increase the rotational speed of the mold 220 in order to reduce the molding cost by improving the productivity. However, the rotational speed is increased as it is. As a result, there is a problem that the cooling time of the molded product cannot be sufficiently secured and this requirement cannot be met.
Therefore, even if the rotational speed of the mold is increased, the molded product can be sufficiently cooled, and a large improvement in productivity can be achieved at a low cost by simply making improvements to the current rotary molding machine. Development of technology that can be used is required.
[0008]
[Problems to be solved by the invention]
The present invention has been made in view of the above problems and requirements, and can sufficiently cool the molded product even when the rotational speed of the mold is increased, and can be easily applied to the current rotary molding machine. It is an object of the present invention to provide a material blowing method in a rotary molding machine that can be implemented only by making improvements.
[0009]
[Means for Solving the Problems]
Order to achieve the above object, the present invention is as described in claim 1, it is arranged in a ring on a base a plurality of molds, and sends the mold ring with the rotation of the base A material blowing method in a rotary molding machine that supplies a material from a material supply unit to the mold and blows air to the material at a predetermined position to form a molded product having a predetermined shape. as, in order to suppress the transfer of heat energy between Rutotomoni, and other fluids to be supplied to the mold and the cold air with cold air in the range of -30 ℃ ~-40 ℃, the low temperature An air flow path is prepared separately from the other fluid flow path, and between the other fluid supplied to the mold and / or another member on the low-temperature air flow path and the low-temperature air. In order to suppress the movement of the thermal energy of the low-temperature air This is a method in which heat is maintained by providing heat retaining means in part or all of the distribution channel .
It said cold air temperature is several tens of degrees lower temperature than the current air for blow (10 ° C. to 15 ° C. or so).
[0010]
According to this method, since the low-temperature air quickly cools the molded product, the molded product can be sufficiently cooled even if the rotational speed of the mold is increased.
Further, to suppress the transfer of heat energy between the other fluid and said cold air supplied to the mold, the other on the other fluid and / or flow path of the cold air supplied to the mold by inhibiting the transfer of thermal energy between the member and the low temperature air, it is possible to hold the temperature of the cold air supplied from a source of cold air at a constant, the ambient by cold air member or other The influence of the fluid can be prevented.
[0011]
In the current rotary mold, the mold 220 is opened at a station immediately before automatic removal, that is, in the station (6) in FIG. 9, so that the molded product can be manually removed. Therefore, the inventor of the present invention makes it unnecessary to manually take out the molded product and keeps the mold closed until immediately before the station (7) where the molded product is taken out by the molded product take-out device 8. The inventors found that the rotational speed of the mold can be further increased.
[0012]
That is, as described in claim 2 , the mold closing period in which the mold is closed can be a method in which the mold is rotated by 225 ° .
In addition, as described in claim 3 , the supply of the material by the rotary molding machine is a step of presetting the material supply start timing from the material supply unit based on the peripheral speed of the mold, when the discharge of material from the material supply unit is started, a step for advancing the material pulling means to the material supply section side, receives the material discharged from the material supply portion in the material pulling means, said mold The step of pulling the material in one direction at the same speed as or faster than the peripheral speed, and the material cutting after the discharge amount or discharge speed of the material reaches a preset amount or speed and cutting the material by means, with cutting the material, said material pulling means is retracted at a preset timing, the step of initiating the supply of material into the mold from the material supply unit The a material may be to adjust the timing for supplying the mold.
[0013]
According to a fourth aspect of the present invention, the material supply by the rotary molding machine includes a step of presetting a material supply stop timing based on a peripheral speed of the mold, and a mold rotation stop means. When operated, at the stop timing, the material cutting means is advanced to the material supply part side to cut the material, and the material pulling means is advanced to the material supply part side, and the mold rotation is stopped. A step of rotating a predetermined number of molds after the means is operated and taking out a molded product in the mold, and adjusting the timing of stopping the supply of the material to the mold .
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a blow molding method according to the present invention will be described with reference to the drawings.
FIG. 1 is an enlarged view of a main part of a rotary molding machine for carrying out the blow molding method of the present invention. FIG. 1 (a) is a longitudinal sectional view of a blow air supply part in the rotary molding machine. It is II sectional drawing of (a).
[0015]
A fluid passage hole 652 for supplying a cooling fluid (cooling water) to the mold 220 is formed through the rotation shaft 651 of the molding unit 6 on the axis of the central axis C. In addition, fluid (pressure oil) flow holes 653 for opening and closing the mold 220 are formed on concentric circles with the central axis C as the center, corresponding to each of the stations (1) to (8). Yes.
Air flow holes 664 for supplying blow air to the material in the mold 220 are formed away from the fluid flow holes 652 and 653, and are attached to the outer peripheral surface of the rotary shaft 651. The heat insulating member 661 made of resin or the like prevents the low temperature air flowing through the air circulation hole 664 from being heated by cooling water or pressurized oil, or the rotating shaft 651 from being adversely affected by the low temperature air.
[0016]
Eight air circulation holes 664 are formed at equal intervals in the peripheral wall of the cylindrical body 662 attached to the outer periphery of the heat insulating member 661 according to the number of molds 220. The cylindrical body 662 is connected to the rotating shaft 651 by a connecting member 669 and rotates integrally with the rotating shaft 651.
A coupler 663 is attached to one opening of the air circulation hole 664, and the blow nozzle 222 (see FIG. 9B) and the air circulation hole 664 are connected via the coupler 663.
[0017]
In addition, a ring-shaped rotating member 666 is attached to a portion where the other opening of the air circulation hole 664 is formed so as to be rotatable with respect to the cylindrical body 662 by a bearing 665. An air supply hole 667 communicating with the other opening of the air circulation hole 664 is formed at a position corresponding to a predetermined station (station {circle around (3)}) of the rotating member 666. When the mold 220 is positioned at the station (3), low temperature air is supplied from the air supply hole 667 to the air circulation hole 664.
The temperature of the low-temperature air supplied for blowing is between -30 ° C and -40 ° C, preferably about -35 ° C.
[0018]
The timing at which the low-temperature air is supplied from the air circulation hole 664 to the material in the mold 220 is the same as the conventional blow air supply timing.
In addition, an air pipe that supplies low-temperature air to the air circulation hole 664 and the air supply hole 667 and an air pipe that connects the air circulation hole 664 and the mold 220 are covered with a heat insulating material to keep the low-temperature air warm. preferable. Further, the bearing 665 provided at the contact portion between the rotating member 666 and the cylindrical body 662 is also preferably made of resin or ceramic having excellent heat insulation.
[0019]
According to the present invention, it is possible to increase the rotational speed of the mold 220 by about 10% to 15% by using the low temperature air of about −35 ° C. for blowing the material.
In the present invention, it is possible to further increase the rotational speed of the mold 220 by extending the mold closing period of the mold 220.
Hereinafter, specific means for extending the mold closing period of the mold 220 will be described.
[0020]
FIG. 2 is a front view of an essential part of an example of a rotary molding machine that can lengthen the mold closing period of the mold 220.
In the vicinity of the die head 5 as a material supply unit for supplying the parison to the mold 220, a timing adjusting device 7 for adjusting the supply timing of the parison supplied from the die head 5 to the mold 220 immediately after the start of the operation of the rotary molding machine. Is provided. The timing adjusting device 7 receives a base 71 fixed to a fixed portion of the rotary molding machine and a parison discharged from the discharge port 5a of the die head 5, and is faster than the discharge speed of the parison from the die head 5, preferably Is a conveyor 72 as material pulling means for pulling the parison in the lateral direction at the same speed as or faster than the peripheral speed of the rotating mold 220, and a parison cutting section for cutting the parison in the vicinity of the discharge port 5a. 73.
In this specification, “circumferential speed” refers to the speed in the tangential direction of the mold 220 on the rotational circumference R of the mold 220 passing through the center of the mold 220.
[0021]
The conveyor 72 supports a motor 721 that is movable in a forward direction approaching the die head 5 and a backward direction away from the die head 5 while being guided by a first guide rail 711 provided on the base 71. A pulley support member 727 extending from the housing to the die head 5 side in parallel with the first guide rail 711 and a rear end (right end in the figure) of the pulley support member 727 so as to be rotatable. A driving pulley 722 that is supported and rotated by driving of the motor 721, a driven pulley 723 that is rotatably supported by the front end (left end in the figure) of the pulley support member 727, the driving pulley 722, and the driven pulley 723 and a belt 724 wound around 723.
The forward / backward movement of the conveyor 72 in the front-rear direction is performed by a driving body 713 such as a motor provided on the base 71. Further, when the motor 721 is driven and the driving pulley 722 rotates, the belt 724 travels in the clockwise direction in FIG. 2 along with the rotation of the driven pulley 723.
[0022]
In the vicinity of the front end of the pulley support member 727, an inverted L-shaped support member 725 is erected, and a rotatable roller 726 is attached to the tip thereof. The roller 726 is positioned so as to be positioned almost directly below the discharge port 5a of the die head 5 when the roller 726 moves forward together with the motor 721 and the pulley support member 727, and is attached to the pulley support member 727. When 72 pulls the parison, it serves as a guide roller that changes the direction of the parison discharged from the discharge port 5a.
[0023]
The parison cutting unit 73 cuts the parison discharged from the die head 5 at a preset timing. The parison cutting portion 73 includes a saddle 731 capable of moving forward or backward toward the die head 5 along a second guide rail 712 parallel to the first guide rail 711 of the base 71, and a saddle via a bracket 733. A rod 735 that moves forward and backward in the same direction as the saddle 731 while being guided by a cylinder 732 attached to the saddle 731, a guide 738 provided in the saddle 731, and a guide hole formed in the bracket 733, and a front end of the rod 735 And a cutter 736 provided on the machine. Since the saddle 731 is connected to the casing of the motor 721, the saddle 731 is integrated with the conveyor 72 and moves forward or backward in the same direction.
[0024]
The piston rod 732a of the cylinder 732 can move forward and backward in the same direction as the forward and backward movement of the rod 735, and the tip of the piston rod 732a and the rear end of the rod 735 are connected by a connecting member 734. Therefore, when the cylinder 732 is driven and the piston rod 732a moves forward and backward, the rod 735 and the cutter 736 move forward or backward toward the die head 5 as the piston rod 732a moves.
[0025]
Next, the material supply procedure in this rotary molding machine will be described together with the operation of the timing adjusting device 7 with reference to FIGS. 3, 4 and 5.
FIG. 3 is a flowchart for explaining the material supply procedure, and FIGS. 4 and 5 are schematic views for explaining the operation of the timing adjusting device 7.
[0026]
First, the timing for supplying the parison discharged from the discharge port 5 a of the die head 5 to the mold 220, that is, the timing for retracting the conveyor 72 and the timing for cutting the parison by the cutter 736 in advance with respect to the rotation timing of the mold 220. Adjust it. For example, the motor driving pulses of the rotation driving unit 65 (see FIG. 9) that rotates the mold 220 are counted, and the best timing for moving the conveyor 72 backward is adjusted, and the timing for driving the cylinder 732 is adjusted. When the mold 220 enters the station {circle around (1)}, the conveyor 72 is moved backward at the timing at which the tip of the parison is accurately supplied to a predetermined position of the mold 220 to cut the parison. Set as follows.
In addition, a necessary and sufficient amount of parison can be supplied to the mold 220 of the station (1) before the mold 220 shifts from the station (1) to the station (2). As described above, the discharge amount (discharge speed) of the parison of the die head 5 is set in advance.
[0027]
The parison discharge timing and discharge amount obtained by the above procedure are unchanged as long as the same mold 220 and the same material parison are used. Therefore, even if the mold 220 is changed or the material of the parison is changed, the rotary molding machine can be operated immediately by simply setting the timing and the discharge amount determined in advance according to the mold 220 and the parison of the material. It is possible to start.
[0028]
As shown in FIG. 4A, in the initial state before the rotary molding machine starts operation, the conveyor 72 of the timing adjustment device 7 and the cutter 736 of the parison cutting unit 73 are in a retracted state separated from the die head 5. It has become.
When the operation of the rotary molding machine is started (step S10), the driving body 713 is driven to advance the conveyor 72 (step S11). As a result, as shown in FIG. 4B, the belt 724 and the roller 726 are positioned directly below the discharge port 5 a of the die head 5.
[0029]
Simultaneously with the advancement of the conveyor 72, the driving of the motor 721 is started and the belt 724 is caused to travel. As described above, it is preferable that the traveling speed of the belt 724 is the same as or slightly higher than the peripheral speed when the mold 220 rotates (step S12).
Thereafter, discharge of the parison P is started from the die head 5 (step S13). The parison P discharged from the die head 5 is pulled laterally by the belt 724 as shown in FIG. 4C (step S14). At this time, the roller 726 positioned directly below the discharge port 5a serves as a guide, and the parison P changes its direction by the roller 726, reaches the rear end of the conveyor 72 together with the belt 724, and is discharged from the machine.
[0030]
The discharge amount (discharge speed) of the parison P is detected by a sensor or the like (not shown). Then, when the discharge amount (discharge speed) of the parison reaches a preset value (step S15), the mold 220 of the rotary molding machine starts to rotate (step S16).
At the same time, the temperature rise of the cutter 736 is started (step S17). After the temperature of the cutter 736 is sufficiently raised, the cylinder 732 is driven as shown in FIG. Is cut with a cutter 736 (step S18). The cutting of the parison P by the cutter 736 is performed intermittently until a first blow button (not shown) for starting the supply of the parison P to the mold 220 is operated (steps S19 and S20).
[0031]
When the first blow button is operated (step S19), the parison P is cut by the cutter 736 at a preset timing, and the parison discharged from the discharge port 5a as shown in FIG. 5B. The parison cutting unit 73 and the conveyor 72 are moved back to a position where they do not interfere with P (step S21). Then, the parison is supplied from the die head 5 to the mold (step S22). The above timing is set in advance so that the tip of the parison P is accurately supplied to the predetermined position of the mold 220 of the station (1). Obtainable.
[0032]
According to the rotary molding machine of this embodiment, a complete molded product can be molded from the first shot, and an incomplete molded product or an adjusted product is not molded. It is not necessary to remove the molded product or the adjusted product. Therefore, there is an advantage that the mold closing period can be lengthened.
FIG. 6 is a timing chart showing the opening / closing timing of the mold 220. As shown in the drawing, the mold opening may be started at the end of the station (6), and the mold opening is performed more than the timing of mold opening in the conventional rotary molding machine shown in FIG. 9 (indicated by a two-dot chain line in FIG. 6). The mold closing period can be lengthened by the angle α.
[0033]
This indicates that the rotation speed of the mold 220 can be increased by the rotation angle α. In this embodiment, the angle of the mold closing period which was initially 205 ° could be extended to 225 ° (α = 20 °), and the rotation speed of the mold 220 could be increased by about 10%. .
Thus, in the rotary molding machine of this embodiment, the rotational speed of the mold 220 can be increased to increase the productivity of the molded product.
[0034]
Next, a procedure for preventing an incompletely molded product from being molded when the rotation of the mold 220 is stopped will be described.
As shown in FIG. 7A, when the mold 220 is rotated and the molded product is being molded, the conveyor 72 and the parison cutting portion 73 of the timing adjusting device 7 are in the retracted position, and the die head 5 The parison discharged from is supplied to the mold 220.
When, for example, an operator operates an operation button (die rotation stop means, not shown) for stopping the rotation of the mold 220 due to the production stop or the like, as shown in FIG. At the same timing, the conveyor 72 of the timing adjusting device 7 advances, and the parison discharged from the die head 5 is received by the belt 724.
[0035]
The advance timing of the conveyor 72, that is, the timing of stopping the parison supply to the mold 220 is set in advance so that a complete molded product is formed by the final shot including the end of the parison. As described in the first embodiment, for example, the timing is such that the motor driving pulse of the rotation driving unit 65 (see FIG. 9) that rotates the mold 220 is counted, and the mold 220 next to the last shot is counted. When entering the station (1), adjustment is made so that the parison is not supplied to the mold 220.
Even after the operation button is operated, the mold 220 continues to rotate for a while, and all molded products in the mold 220 are taken out by the molded product take-out section 8 (see FIG. 9) in the station (7). After that, it stops automatically.
[0036]
As in the first embodiment, the conveyor 72 is advanced so that the parison discharged from the die head 5 is received by the belt 724, and the cutter 736 is intermittently advanced / retracted from the discharge port 5a. The parison to be discharged may be cut. Further, when the operation button is operated, the cutter 736 may be advanced to cut the parison, and then the conveyor 72 may be advanced.
[0037]
FIG. 8 shows the temperature at the bottom of the bottle when the timing adjusting device, the material supply timing and the material supply stop timing shown in FIGS. 2 to 7 are used, and the low temperature air at a temperature of −35 ° C. is used as the blow air. This is a graph of the change in.
When blow with low temperature air is not performed, that is, with high temperature (about 11 ° C.) air, the temperature gradually rises after the bottle is taken out from the mold 220. It seems that the heat of the part moves to the bottom when the bottle is taken out from the mold 220.
[0038]
On the other hand, in the case of using the low temperature air, it can be seen that the cooling by the low temperature air is efficiently performed, and the temperature rise after the bottle is taken out from the mold 220 is hardly observed. This indicates that the rotation speed of the mold 220 can be increased by about 20% to 25% from the state where the mold closing period of the mold 220 is not extended and the low temperature air is not blown.
Thus, in the present invention, the rotational speed of the mold 220 can be increased by 20% or more simply by using low-temperature air and extending the mold closing period, and productivity can be improved.
[0039]
Although preferred embodiments of the present invention have been described, the present invention is not limited to the above-described embodiments.
For example, in the above description, the low temperature air is supplied to the mold 220 from the outer peripheral side of the rotary shaft 651 without passing through the rotary shaft 651, but the low temperature air is supplied to the mold 220 through the inside of the rotary shaft 651. May be supplied. In this case, a resin or ceramic coating excellent in heat insulation may be formed on the inner peripheral surface of the low-temperature air circulation hole. In addition, as an example of extending the mold closing period, the timing of supplying the material to the mold 220 and adjusting the timing of stopping the material supply have been described as examples, but the mold closing is performed by other means. As long as the period can be extended, the means is not necessarily limited to the means described in the above embodiment.
[0040]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to increase the rotational speed of the mold by about 10% to 15% simply by making a simple improvement to the current rotary molding machine. In addition, by extending the mold closing period, the mold rotation speed can be improved by about 20% to 25%, and the productivity of the molded product can be increased.
[Brief description of the drawings]
FIG. 1 is a front view of an essential part of an embodiment of a rotary molding machine used for carrying out the present invention.
FIG. 2 is a front view of an essential part of an example of a rotary molding machine capable of extending the mold closing period of the mold.
FIG. 3 is a flowchart for explaining a material supply procedure by the timing adjustment device of FIG. 2;
FIG. 4 is a schematic diagram for explaining the operation of the timing adjustment device of FIG. 2;
FIG. 5 is a schematic diagram for explaining the operation of the timing adjustment device continued from FIG. 4;
6 is a timing chart for explaining a mold closing period of the mold when the timing adjusting device of FIG. 2 is used. FIG.
7 is an operation diagram illustrating a procedure for stopping supply of material by the timing adjustment device of FIG. 2; FIG.
FIG. 8 is a diagram for explaining the effect of the present invention when low-temperature air and the timing adjustment device of FIG. 2 are used.
FIG. 9A is a front view of a main part of a conventional rotary blow molding machine for forming a hollow container, and FIG. 9B is an enlarged view showing a state of blow at the station (3). .
[Explanation of symbols]
65 Rotation Drive Unit 651 Rotating Shaft 652, 653 Fluid Flow Hole 661 Heat Insulation Member 662 Tubular Body 663 Coupler 664 Air Flow Hole 665 Bearing 666 Rotation Member

Claims (4)

A plurality of molds are annularly arranged on a base, and the molds are annularly sent along with the rotation of the base, and a material is supplied from the material supply unit to the molds. A material blowing method in a rotary molding machine that blows air to form a molded product of a predetermined shape,
As air for blowing Rutotomoni using low temperature air in the range of -30 ℃ ~-40 ℃,
In order to suppress the movement of thermal energy between the other fluid supplied to the mold and the low temperature air, a flow path of the low temperature air is prepared separately from the flow path of the other fluid, In order to suppress the movement of thermal energy between the other fluid supplied to the mold and / or other members on the low-temperature air distribution path and the low-temperature air, a part of the low-temperature air distribution path Alternatively, a material blowing method in a rotary molding machine, characterized in that all of them are provided with a heat retaining means . 2. The material blowing method in the rotary molding machine according to claim 1 , wherein a mold closing period in which the mold is closed is a period in which the mold is rotated by 225 [deg .]. Based on the peripheral speed of the mold, the supply of the material by the rotary molding machine pre-sets the material supply start timing from the material supply unit, and material discharge from the material supply unit is started. when that includes the steps of advancing the material pulling means to the material supply section side, it receives the material discharged from the material supply portion in the material pulling means, than the peripheral speed and the same speed or the circumferential speed of the mold A step of pulling the material in one direction at a high speed, a step of cutting the material by the material cutting means after a discharge amount or discharge speed of the material reaches a preset amount or speed, and a material with cutting the said material pulling means is retracted at a preset timing, and a step of initiating the supply of material into the mold from the material supply unit, to supply material into the mold Blowdown of the material in the rotary molding machine according to claim 1 or 2, characterized in that to adjust the timing. The supply of the material by the rotary molding machine is a step of presetting the material supply stop timing based on the peripheral speed of the mold, and when the mold rotation stop means is operated, at the stop timing, A step of cutting the material by advancing the material cutting means toward the material supply unit, and advancing the material pulling means toward the material supply unit; and a predetermined number of molds after the mold rotation stopping means is operated 4. The method according to claim 1 , further comprising: a step of rotating the mold and taking out a molded product in the mold, and adjusting a timing of stopping the supply of the material to the mold. A material blowing method in the rotary molding machine described.

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