Pellet manufacturing device and pellet manufacturing method

Abstract

The present invention suppresses the occurrence of variations in the diameter of a strand during a preparation stage before the manufacturing of pellets begins. A pellet manufacturing device 10 comprises an extrusion part 20, a grip part 42, a movement part 50, and a strand cutter 56. The extrusion part 20 extrudes a molten resin R as a string-like strand S. The grip part 42 grips the strand S extruded from the extrusion part 20. The movement part 50 moves the grip part 42. The strand cutter 56 cuts the strand S conveyed by the movement of the grip part 42.

Description

Pellet manufacturing device and pellet manufacturing method

[0001] The present disclosure relates to a pellet manufacturing apparatus and a pellet manufacturing method.

[0002] Patent Document 1 discloses a pellet manufacturing apparatus in which strands discharged from a die are solidified in a cooling tank and then sent to a strand cutter where they are cut.

[0003] Japanese Patent Application Laid-Open No. 2022-134497

[0004] Patent Document 1 does not disclose a configuration for bringing the tip of the strand to the strand cutter in the preparation stage before starting pellet production. If a user manually transports the strand to the strand cutter and then starts production, the magnitude of the external force acting on the strand may vary depending on the user's skill, which may result in variations in strand diameter. Therefore, there is room for improvement in strand handling in the preparation stage before starting pellet production.

[0005] The present disclosure has been made to solve such problems, and aims to suppress the occurrence of variations in strand diameter in the preparation stage before the start of pellet production.

[0006] In one embodiment of the pellet manufacturing apparatus, the gripping unit grips the strand extruded from the extrusion unit, and the moving unit moves the gripping unit.

[0007] A pellet manufacturing method according to one embodiment includes a step of gripping a strand extruded from an extrusion section with a gripping section, and a step of moving the strand to a cutting section by moving the gripping section with a moving section.

[0008] According to the pellet manufacturing device of the present disclosure, it is possible to suppress variations in the diameter of the strands in the preparation stage before the start of pellet manufacturing.

[0009] According to the pellet manufacturing method of the present disclosure, it is possible to suppress the occurrence of variations in the diameter of the strands in the preparation stage before the start of pellet manufacturing.

[0010] 1 is a front view showing a pellet manufacturing apparatus according to an embodiment of the present disclosure. FIG. 1 is a block diagram of the pellet manufacturing apparatus of FIG. 1. FIG. 2 is a front view showing a state in which pellets are manufactured using the pellet manufacturing apparatus of FIG. 1. FIG. 3 is a plan view showing a state in which molten resin is extruded from a die of the pellet manufacturing apparatus of FIG. 1 to form strands. FIG. 4 is an enlarged front view of a conveying section of the pellet manufacturing apparatus of FIG. 1. FIG. 5 is an enlarged front view of an upstream support section of the pellet manufacturing apparatus of FIG. 1. FIG. 6 is an enlarged front view of a downstream support section of the pellet manufacturing apparatus of FIG. 1. FIG. 7 is a front view showing a state in which an operation check is being performed before pellet manufacturing starts in the pellet manufacturing apparatus of FIG. 1. FIG. 8 is a front view showing a state in which an operation of conveying a strand before pellet manufacturing starts in the pellet manufacturing apparatus of FIG. 1 has started. FIG. 9 is a front view showing a state in which an operation of conveying a strand before pellet manufacturing starts in the pellet manufacturing apparatus of FIG. 1 is in the middle of the operation of conveying a strand before pellet manufacturing starts. FIG. 10 is a front view showing a state in which the operation of conveying a strand has finished in the pellet manufacturing apparatus of FIG. 1. FIG. 11 is a front view showing a pellet manufacturing apparatus of Modified Example 1. FIG. 12 is a cross-sectional view showing a conveying section of a pellet manufacturing apparatus of Modified Example 2.

[0011] The present embodiment will be described below with reference to the accompanying drawings. Note that the same reference numerals are used to designate components having the same functions, and repeated description will be omitted.

[0012] [Configuration of the pellet manufacturing apparatus] Figure 1 shows a pellet manufacturing apparatus 10 according to this embodiment. Figure 2 shows a block diagram of each component of the pellet manufacturing apparatus 10. As shown in Figure 1, the pellet manufacturing apparatus 10 is installed on a floor 2 of a factory. In the following, each direction will be defined and the arrangement of each component will be described assuming that the floor 2 is a horizontal plane. A pedestal 14, which will be described later, is provided on the floor 2. The pedestal 14 has an upper surface 14A.

[0013] As shown in Fig. 2, the pellet production apparatus 10 includes an extrusion unit 20, a control unit 30, a gripping unit 42, a moving unit 50, and a strand cutter 56. The pellet production apparatus 10 also includes an operation panel 12, an upstream cutter 16, a cooling unit 60 (Fig. 1), a water tank position detection unit 82, a water tank position changing unit 86, a support unit 110 (Fig. 1), and a measurement unit 130. Components other than those shown in Fig. 2 will be described later.

[0014] The operation of the pellet manufacturing apparatus 10 is started, stopped, and set by a user through an operation panel 12. The operation panel 12 is, for example, a touch panel, and allows information to be input and displayed.

[0015] 8, in the pellet manufacturing apparatus 10, pre-extrusion of the strand S is performed as one of the preparation steps before starting the production of the pellets P (FIG. 3). The pre-extrusion of the strand S will be described later.

[0016] 9, in the pellet manufacturing apparatus 10, as one of the preparation stages before starting to manufacture the pellets P, the strand S extruded from the extrusion unit 20 is cooled in the cooling unit 60 and is transported to the strand cutter 56 by the gripping unit 42 and the moving unit 50. Note that the transport of the strand S by the gripping unit 42 and the moving unit 50 is performed after the strand S has been provisionally extruded.

[0017] 3, in the pellet manufacturing apparatus 10, when the production of pellets P is started, the strand S extruded from the extrusion section 20 is conveyed while being cooled in the cooling section 60, and is cut by the strand cutter 56 to form pellets P. In this way, the production of pellets P using the pellet manufacturing apparatus 10 includes two stages: a pre-production preparation stage and a production stage.

[0018] In the following description of the pellet manufacturing apparatus 10, the horizontal direction from the extrusion unit 20 toward the strand cutter 56 is referred to as the Y direction. The direction perpendicular to the Y direction and vertical to the Z direction is referred to as the X direction.

[0019] The Y direction is an example of a conveying direction of the strand S. The X direction is an example of a crossing direction that intersects with the Y direction. The tip side of the arrow Y corresponds to the downstream side of the conveying direction of the strand S. The base end side of the arrow Y corresponds to the upstream side of the conveying direction of the strand S. The tip side of the arrow Z corresponds to the upper side in the vertical direction. The base end side of the arrow Z corresponds to the lower side in the vertical direction. The tip side of the arrow X corresponds to the front side of the pellet manufacturing apparatus 10. The base end side of the arrow X corresponds to the back side of the pellet manufacturing apparatus 10. The specific configuration of the pellet manufacturing apparatus 10 will be described below.

[0020] <Extrusion Section> As shown in Fig. 1 , the extrusion section 20 includes a drive section 22, a cylinder 24, an injection section 27, a die 28, and an upstream cutter 16. The drive section 22 is configured to include, for example, a motor and a reducer. The cylinder 24 is a hollow member extending with the Y direction as its axial direction. A screw 25 is provided in the hollow section of the cylinder 24, and a heater 26 is provided on the outer surface or inside thereof. The screw 25 is disposed with the Y direction as its axial direction, and is rotated by the drive section 22. The number of screws 25 may be either one or more.

[0021] The feed section 27 is connected to the interior of the cylinder 24. The resin material used to make the pellets P (FIG. 3) is fed into the feed section 27. Examples of the resin material include thermoplastic resins. Examples of the thermoplastic resins that can be used include polyethylene, polypropylene, polyamide, polyethylene terephthalate, polyimide, polyether ether ketone, polystyrene, polyvinyl chloride, polycarbonate, polymethyl methacrylate, acrylonitrile butadiene styrene resin, polybutylene terephthalate resin, and biodegradable resins (PLA, PBS, PBAT). These resins may be used alone or as a mixture of multiple types.

[0022] The operation of the extrusion section 20 is controlled by a control section 30 (FIG. 2), which will be described later. The raw material fed into the cylinder 24 is kneaded by the rotation of the screw 25 and melted by the heat from the heater 26. The melted resin material (hereinafter referred to as molten resin R) is transferred to a die 28.

[0023] As shown in FIG. 4 , the die 28 has a plurality of through holes 28A formed at intervals in the X direction. The molten resin R is extruded from the through holes 28A to form string-like strands S. In other words, the extrusion unit 20 extrudes the molten resin R as string-like strands S. Note that FIG. 4 shows, as an example, three strands S (S1, S2, S3) extruded from the extrusion unit 20. As viewed from above in the Z direction, the X-direction diameter of strand S1 is defined as W1, the X-direction diameter of strand S2 is W2, and the X-direction diameter of strand S3 is W3. The respective sizes of the diameters W1, W2, and W3 are measured by a measuring unit 130 ( FIG. 2 ), which will be described later.

[0024] 2, the control unit 30 is a personal computer, and includes a CPU (Central Processing Unit) 32 and a memory 34. The CPU 32 and the memory 34 are connected to a common bus 33. The CPU 32 executes programs stored in the memory 34, thereby realizing various processes of the pellet manufacturing apparatus 10.

[0025] The control unit 30 can transmit and receive information to and from the operation panel 12, the upstream cutter 16, the extrusion unit 20, the gripping unit 42, the moving unit 50, the strand cutter 56, the upstream shower 64, the downstream shower 66, the water tank position detection unit 82, and the water tank position change unit 86. Furthermore, the control unit 30 can transmit and receive information to and from the roller lifting unit 92, the temperature measurement unit 102, the temperature change unit 104, the upstream drive unit 114, the downstream drive unit 124, and the measurement unit 130.

[0026] <Gripping Section> As shown in Fig. 5, the gripping section 42 has a support frame 44, bearings 45A and 45B, a pair of rollers 46, and a bearing drive section 49. The support frame 44 has a vertical wall section 44A that stands upright in the Z direction. Two vertical wall sections 44A are provided with a gap in the X direction. Note that Fig. 5 shows one vertical wall section 44A. The bearing 45A is fixed to the vertical wall section 44A. The bearing 45B is provided on the vertical wall section 44A so as to be movable upward and downward in the Z direction. The bearing 45B is located above the bearing 45A in the Z direction.

[0027] The roller pair 46 includes a lower roller 47 and an upper roller 48. The lower roller 47 is disposed with its axial direction aligned with the X direction. Both ends of the lower roller 47 in the X direction are rotatably supported by bearings 45A. The lower roller 47 has an outer peripheral surface 47A. The upper roller 48 is disposed with its axial direction aligned with the X direction. Both ends of the upper roller 48 in the X direction are rotatably supported by bearings 45B. The upper roller 48 has an outer peripheral surface 48A. Both the lower roller 47 and the upper roller 48 are driven rollers that are not driven by a motor. The distance between the uppermost portion of the outer peripheral surface 47A in the Z direction and the lowermost portion of the outer peripheral surface 48A in the Z direction is defined as nip distance d. The portion of the roller pair 46 where nip distance d is obtained is defined as nip portion N.

[0028] As an example, the bearing drive unit 49 includes a cam 49A and a motor 49B that rotates the cam 49A. The cam 49A is rotatably mounted on the vertical wall portion 44A. A portion of the cam 49A supports the bearing 45B. The operation of the motor 49B is controlled by the control unit 30 ( FIG. 2 ). By changing the rotation angle of the cam 49A, the bearing 45B moves upward or downward in the Z direction. In other words, by the bearing drive unit 49 driving the bearing 45B, the upper roller 48 can move upward or downward in the Z direction. Then, by moving the upper roller 48 upward or downward in the Z direction, the nip distance d can be changed.

[0029] As an example, the nip distance d includes a nip distance d1 when the strand S is sandwiched between the lower roller 47 and the upper roller 48, and a nip distance d2 (>d1) when the upper roller 48 is separated from the strand S. The nip distances d1 and d2 are preset in the control unit 30 ( FIG. 2 ). The nip distance d1 is preset so that the pressure force acting on the strand S in the Z direction falls within an allowable range when the roller pair 46 sandwiches the strand S. In other words, the nip distance d1 is preset so that deformation of the strand S falls within an allowable range. Furthermore, the nip distance d1 is preset so that a force (conveying force) that pulls the strand S downstream in the Y direction acts on the strand S when the moving unit 50 moves.

[0030] The fact that the strand S is sandwiched between the roller pair 46 is included in the fact that "the strand S is gripped by the gripping portion 42." In other words, the gripping portion 42 grips the strand S extruded from the extrusion portion 20 (FIG. 1).

[0031] <Moving Unit> As shown in FIG. 5, the moving unit 50 is provided on a support frame 77 (FIG. 1), which will be described later. The moving unit 50 is configured, for example, as an electric linear actuator. The moving unit 50 includes a guide rail 52 and a carriage 54. The guide rail 52 extends in the Y direction. The carriage 54 is guided by the guide rail 52, allowing it to move back and forth along the Y direction. A vertical wall portion 44A is fixed to the carriage 54. As a result, the moving unit 50 supports the gripping portion 42 so that it can move in the Y direction. The operation of the moving unit 50 is controlled by the control unit 30 (FIG. 2).

[0032] Here, the gripping unit 42 and the moving unit 50 constitute the conveying unit 40. That is, the conveying unit 40 grips the strand S and conveys the strand S toward a strand cutter 56 (FIG. 1) described below. The gripping unit 42 may grip the strand S at any time before, at the same time as, or after the moving unit 50 starts to move.

[0033] 3, the upstream cutter 16 is located downstream in the Y direction relative to the die 28 and upstream in the Y direction relative to a camera 132, which will be described later. The upstream cutter 16 includes a blade portion 17 that is movable in the Z direction. The blade portion 17 moves in the Z direction relative to the strand S, thereby enabling the strand S to be cut. The upstream cutter 16 may cut the strand S, for example, when the operation of the extrusion portion 20 is confirmed in the preparation stage or when the production of the pellets P is completed.

[0034] <Strand cutter> As shown in Figure 3, the strand cutter 56 is an example of a cutting unit that cuts the strand S transported by the movement of the gripping unit 42. The strand cutter 56 has a main body 57, a strand receiving unit 58, and a rotary blade 59. The main body 57 is installed on the floor surface 2. The strand receiving unit 58 is provided on the upstream side of the main body 57 in the Y direction. The strand receiving unit 58 has an upper roller 58A and a lower roller 58B, which are an example of a pair of rotating members.

[0035] The upper roller 58A and the lower roller 58B are each rotatable with the X direction as their axial direction. The upper roller 58A and the lower roller 58B sandwich the strand S and rotate to transport the strand S. The rotary blade 59 is provided inside the main body 57 so as to be rotatable with the X direction as its axial direction.

[0036] The rotational movement of the upper roller 58A and the lower roller 58B and the rotational movement of the rotary blade 59 are controlled by the control unit 30 (FIG. 2). The strand cutter 56 receives the strand S conveyed by the gripping unit 42 at the strand receiving unit 58. The strand cutter 56 then cuts the strand S by the rotation of the rotary blade 59. The strand S cut by the rotary blade 59 is discharged to the outside as a plurality of pellets P.

[0037] 3, the cooling section 60 is located between the extrusion section 20 and the strand cutter 56, and cools the strand S. Specifically, the cooling section 60 has an upper cooling section 62 located above the strand S in the Z direction, and a lower cooling section 72 located below the upper cooling section 62 in the Z direction.

[0038] (Upper Cooling Section) The upper cooling section 62 has an upstream shower 64 and a downstream shower 66. The upstream shower 64 ejects water WT, which is an example of a liquid. The upstream shower 64 also ejects the water WT toward a portion of the strand S that is downstream in the Y direction from a portion photographed by a camera 132 (described later) and upstream in the Y direction from a portion gripped by the gripping section 42. In other words, the upstream shower 64 is an example of an upstream cooling section that is located between the extrusion section 20 and the gripping section 42 and cools the strand S. The strand S hardens when cooled by the water WT.

[0039] The downstream shower 66 is located downstream in the Y direction relative to the upstream shower 64 and above the strand S in the Z direction. As an example, the downstream shower 66 is provided at three locations spaced apart in the Y direction. Furthermore, the downstream shower 66 is capable of ejecting water WT (FIG. 10) toward the strand S at multiple locations in the X direction.

[0040] (Lower Cooling Section) The lower cooling section 72 has a water tank 74, an immersion roller 96, a water tank position detection section 82, a water tank position change section 86, a roller lifting section 92, a temperature measurement section 102, and a temperature change section 104 (FIG. 2).

[0041] The water tank 74 is placed on the top surface 14A via a water tank position changer 86. The water tank 74 has a rectangular bottom wall 75 whose dimension in the Y direction is larger than its dimension in the X direction, and a side wall 76 that stands upright above the bottom wall 75 in the Z direction. In other words, the water tank 74 is formed in a box shape that opens upward in the Z direction and extends in the Y direction. The water tank 74 is an example of a storage tank that stores water WT. A support frame 77 extending in the Y direction is attached to the side wall 76. Furthermore, guide frames 93 and 94, which will be described later, are attached to the side wall 76.

[0042] The cooling water (water WT) flows from the downstream side to the upstream side in the moving direction of the strand S, and the water temperature is adjusted so that the temperature on the upstream side becomes the set temperature.

[0043] <Water Tank Position Detector> As shown in Fig. 3, the water tank position detector 82 is an example of a position detector. The water tank position detector 82 detects the position of the water tank 74 in the Y direction relative to the position of the extrusion unit 20 in the Y direction. Specifically, the water tank position detector 82 has a laser transmitter 83 and a laser receiver 84. The laser transmitter 83 is attached to the upstream end of the water tank 74 in the Y direction. The laser transmitter 83 emits laser light LT downward in the Z direction.

[0044] The laser receiver 84 is fixed to the floor surface 2 so that the surface that receives the laser light LT is located at the upper end in the Z direction. When the laser receiver 84 receives (receives) the laser light LT, it detects that the upstream end of the water tank 74 in the Y direction is located at the upstream end in the Y direction of its movable range. When the laser receiver 84 does not receive the laser light LT, it is determined that the water tank 74 is located in a position shifted downstream in the Y direction. The downstream position of the water tank 74 in the Y direction can be detected based on the amount of operation of the water tank position change unit 86, which will be described later, etc.

[0045] It should be noted that bottom wall 75 is not necessarily positioned along a horizontal plane (X-Y plane). For this reason, an acceleration sensor may be provided in water tank 74 as water tank position detection unit 82. That is, the inclination of water tank 74 relative to the horizontal plane may be measured based on the output of the acceleration sensor, and the position of water tank 74 in the Y and Z directions may also be detected. In this way, detecting the position of water tank 74 also includes detecting the angle of water tank 74.

[0046] <Water Tank Position Changing Unit> As shown in FIG. 3 , water tank position changing unit 86 is an example of a position changing unit. Water tank position changing unit 86 is provided on bottom wall 75 and placed on top surface 14A. Water tank position changing unit 86 changes the Y-direction position of water tank 74 based on the Y-direction position detection result of water tank position detection unit 82. As an example, water tank position changing unit 86 includes an upstream drive roller 87A, a downstream drive roller 87B, and multiple driven rollers 87C. The operation of water tank position changing unit 86 is controlled by control unit 30 ( FIG. 2 ).

[0047] When the upstream drive roller 87A is rotated, the water tub 74 is moved upstream in the Y direction. When the downstream drive roller 87B is rotated, the water tub 74 is moved downstream in the Y direction by a preset distance. A plurality of driven rollers 87C supports the water tub 74 so that it can move in the Y direction.

[0048] <Roller Elevating Unit> As shown in Figure 3, the roller elevating unit 92 has guide frames 93 and 94, multiple elevating frames 95, and multiple immersion rollers 96. The guide frames 93 and 94 are attached to the side wall portion 76 and extend in the Z direction. The elevating frame 95 extends in the Y direction. Both ends of the elevating frame 95 in the Y direction are supported by the guide frames 93 and 94. The guide frames 93 and 94 and the elevating frame 95 are configured as linear actuators. In other words, the elevating frame 95 can rise and fall in the Z direction.

[0049] The multiple immersion rollers 96 are an example of immersion members, and each extends with its axial direction aligned in the X direction. The multiple immersion rollers 96 are arranged at intervals in the Y direction. Both ends of the multiple immersion rollers 96 in the X direction are rotatably supported by multiple lifting frames 95. The multiple immersion rollers 96 are lowered in accordance with the lowering operation of the lifting frames 95, thereby coming into contact with the strand S and immersing the strand S in the water WT in the water tank 74. In this way, the multiple immersion rollers 96 are positioned between the extrusion section 20 and the strand cutter 56, and are configured to immerse the strand S in the water WT.

[0050] <Temperature Measurement Unit> As shown in Fig. 3, the temperature measurement unit 102 is provided in the water tank 74. The temperature measurement unit 102 measures the temperature of the water WT contained in the water tank 74. The measured temperature data is sent to the control unit 30 (Fig. 2).

[0051] <Temperature Changing Unit> As shown in Fig. 3, the temperature changing unit 104 has a tank 105, a pipe 106, a pump 107, a heater 108, and a cooler 109. Water WT is stored inside the tank 105. The pipe 106 connects the inside of the tank 105 to the inside of the water tank 74. The pump 107 pumps up the water WT from the tank 105 and sends it to the pipe 106. The heater 108 is provided so as to be able to heat the water WT in the tank 105. The cooler 109 is provided so as to be able to cool the water WT in the tank 105.

[0052] The temperature changing unit 104 changes the temperature of the water WT based on the temperature T1 ( FIG. 2 ) measured by the temperature measuring unit 102. For example, if the preset temperature range is a range of temperature T2 or higher and temperature T3 or lower ( FIG. 2 ) and temperature T1 is lower than temperature T2, the temperature changing unit 104 operates the heater 108 to heat the water WT. On the other hand, if temperature T1 is higher than temperature T3, the temperature changing unit 104 operates the cooler 109 to cool the water WT. In this way, the heated or cooled water WT is supplied to the water tank 74, thereby changing (adjusting) the temperature of the water WT in the water tank 74.

[0053] 3 , the support section 110 is located between the extrusion section 20 and the strand cutter 56, and supports the strand S. Specifically, the support section 110 has an upstream support section 112 and a downstream support section 122.

[0054] (Upstream Support Portion) As shown in Fig. 6 , the upstream support portion 112 includes an arm member 113, an upstream drive portion 114, a support roller 115, and a connecting pin 116. The arm member 113 is a plate member that is rectangular when viewed from the X direction. Two arm members 113 are provided spaced apart in the X direction, but Fig. 6 shows only one arm member 113. One axial end of the arm member 113 is connected to the corner portion 76A by the connecting pin 116. The corner portion 76A is a portion that is located at the upstream end of the side wall portion 76 in the Y direction and at the upper end in the Z direction.

[0055] The upstream drive unit 114 includes a motor and a gear, and rotates the arm member 113 around the connecting pin 116. In other words, the arm member 113 is an example of a displacement member, and is provided so that its position relative to the strand S can be changed. The support roller 115 is rotatably provided at the other end of the arm member 113 in the axial direction. The support roller 115 has an outer circumferential surface 115A. The support roller 115 supports the strand S by having a portion of the outer circumferential surface 115A come into contact with the strand S. Note that when it is not necessary to support the strand S, the arm member 113 is rotated downward in the Z direction, and the support roller 115 is retracted downward in the Z direction.

[0056] (Downstream Support Portion) As shown in Fig. 7 , the downstream support portion 122 includes an arm member 123, a downstream drive portion 124, a support roller 125, and a connecting pin 126. The arm member 123 is a plate member that is rectangular when viewed from the X direction. Two arm members 123 are provided spaced apart in the X direction, but Fig. 7 shows only one arm member 123. One axial end of the arm member 123 is connected to the corner portion 76B by the connecting pin 126. The corner portion 76B is a portion that is located at the downstream end of the side wall portion 76 in the Y direction and at the upper end in the Z direction.

[0057] The downstream drive unit 124 includes a motor and a gear, and rotates the arm member 123 around the connecting pin 126. In other words, the arm member 123 is an example of a displacement member, and is provided so that its position relative to the strand S can be changed. The support roller 125 is rotatably provided at the other end of the arm member 123 in the axial direction. The support roller 125 has an outer circumferential surface 125A. The support roller 125 supports the strand S by having a portion of the outer circumferential surface 125A come into contact with the strand S. Note that when it is not necessary to support the strand S, the arm member 123 is rotated downward in the Z direction, and the support roller 125 is retracted downward in the Z direction.

[0058] <Measurement Unit> The measurement unit 130 will be described with reference to Figures 1, 2, and 4. The measurement unit 130 includes, for example, a camera 132 and a calculation unit 134. The measurement unit 130 measures the diameter W of the strand S in the X direction. The calculation unit 134 may be incorporated into the control unit 30 (Figure 2).

[0059] The camera 132 photographs the strand S extruded from the die 28 from above in the Z direction. The image information acquired by the camera 132 is sent to the calculation unit 134. The calculation unit 134, like the control unit 30, has a CPU, memory, etc. The calculation unit 134 then performs binarization processing on the image information to calculate the diameter W1 of the strand S1, the diameter W2 of the strand S2, and the diameter W3 of the strand S3. Furthermore, the calculation unit 134 calculates the average values ​​of the diameters W1, W2, and W3. The calculated average value information is sent to the control unit 30.

[0060] The control unit 30 controls the movement speed of the moving unit 50 based on the diameter W of the strand S in the X direction measured by the measuring unit 130. Specifically, the control unit 30 controls the movement speed of the moving unit 50 to decrease when the average value of the diameter W of the strand S in the X direction is smaller than a preset value. Furthermore, the control unit 30 controls the movement speed of the moving unit 50 to increase when the average value of the diameter W of the strand S in the X direction is larger than a preset value. The control unit 30 controls the movement speed of the moving unit 50 to maintain the movement speed when the average value and the preset value for the diameter W of the strand S in the X direction are approximately equal.

[0061] [Operation of the Pellet Manufacturing Apparatus] In the pellet manufacturing apparatus 10, after the start of an operation is selected on the operation panel 12 (FIG. 2), each process (step) described below is automatically performed until the stop of the operation is selected. Each process is performed by the CPU 32 reading, developing, and executing a program from the memory 34.

[0062] As shown in Figure 8, in the pellet manufacturing apparatus 10, a preliminary extrusion process of the strand S is performed as a preparation stage before the start of production. At this time, the water tank 74 is positioned close to the strand cutter 56. The gripping unit 42 is positioned at a position (start position) closest to the upstream support unit 112. In this state, the extrusion unit 20 extrudes the molten resin R as the strand S. The extruded strand S is photographed by the camera 132 and cooled by the upstream shower 64.

[0063] The control unit 30 performs image analysis (for example, analysis based on color differences) based on the information captured by the camera 132. This determines whether or not there is any foreign matter (such as dust) in the strand S. If there is any foreign matter in the strand S, the operation of the pellet manufacturing device 10 is stopped, and a warning message is displayed on the operation panel 12 (FIG. 2). On the other hand, if there is no foreign matter in the strand S, the extrusion of the strand S is stopped, and the extruded strand S is cut by the upstream cutter 16. The cut strand S falls and is collected in a container. Then, the process proceeds to the next step.

[0064] It should be noted that the "foreign matter" in the strand S refers to any matter that may affect the operation of the strand cutter 56, and specifically refers to solid matter such as metal powder that may wear down the strand cutter 56. Gel-like matter, unmelted matter, and the like are not required to stop the extrusion of the strand S, and are therefore not included in the "foreign matter."

[0065] As shown in Figure 9, the water tank position change unit 86 operates to move the water tank 74 upstream in the Y direction. The movement of the water tank 74 is stopped when the laser receiver 84 receives the laser light LT. Next, the molten resin R is extruded from the extrusion unit 20 as a string-like strand S (an example of a process for extruding the strand S). At this time, the upstream drive unit 114 (Figure 2) is driven, causing the upstream support unit 112 to support the strand S.

[0066] As shown in Figure 5, the extruded strand S passes between the lower roller 47 and the upper roller 48, which has retreated upward, and advances downstream in the Y direction. When the length L1 (Figure 10) of the portion of the strand S extending (protruding) downstream from the gripping portion 42 reaches a preset length in the Y direction, the cam 49A is rotated. This lowers the position of the upper roller 48, causing the strand S to be sandwiched between the roller pair 46 (an example of a process in which the strand S is gripped by the gripping portion 42).

[0067] The force with which the gripping portion 42 grips the strand S is kept to the minimum force that allows the strand S to move downstream in the Y direction. Therefore, even if the strand S is deformed by the operation of the gripping portion 42, the deformed portion of the strand S is limited to the portion gripped by the gripping portion 42. In other words, the portion not gripped by the gripping portion 42 is less likely to be deformed.

[0068] 10 , after the strand S is gripped by the gripping unit 42, the moving unit 50 moves the gripping unit 42 toward the strand cutter 56. At this time, a plurality of downstream showers 66 spray water WT onto the strand S, thereby cooling the strand S. In this manner, the strand S moved by the moving unit 50 is moved (transported) in a harder state than before cooling. The gripping unit 42 that has gripped the strand S is moved to the strand cutter 56 (an example of a process in which the gripping unit 42 is moved by the moving unit 50 to transport the strand S to the strand cutter 56).

[0069] 11 , when the gripping unit 42 reaches the downstream end of the guide rail 52 ( FIG. 5 ) in the Y direction, the downstream drive unit 124 ( FIG. 2 ) is driven, causing the downstream support unit 122 to support the strand S. Then, the leading end (downstream end) of the strand S enters the strand receiving unit 58 as the moving unit 50 moves. In this way, the leading end of the strand S is transferred to the strand receiving unit 58. When the leading end of the strand S reaches the strand cutter 56, the transport of the strand S in the preparation process is completed.

[0070] As shown in Figure 5, the upper roller 48 is moved upward in the Z direction before the plurality of immersion rollers 96 (Figure 11) start to descend. In other words, the nipped state of the strand S at the nip portion N is released. Then, the gripping portion 42 is moved by the moving portion 50 to the upstream end (start position) of the guide rail 52 in the Y direction.

[0071] As shown in Figure 3, after the strand S has been transferred to the strand receiving section 58, the roller lifting section 92 performs a lowering operation. As a result, the strand S is immersed in the water WT in the water tank 74 by the multiple immersion rollers 96 and cooled. The operation of the multiple downstream showers 66 is stopped. Then, the manufacturing process begins. Specifically, the extrusion and movement of the strand S is resumed, and the strand S is cut by the strand cutter 56 (an example of a process in which the strand cutter 56 cuts the strand S). As a result, multiple pellets P are formed. The formed multiple pellets P are collected.

[0072] As described above, according to the pellet manufacturing apparatus 10, in the preparation stage before the production of pellets P, the gripping unit 42 grips the strand S extruded from the extrusion unit 20. The moving unit 50 moves the gripping unit 42. As a result, the strand S is automatically transported to the strand cutter 56. When the production of pellets P starts, the strand cutter 56 cuts the strand S, thereby producing a plurality of pellets P. In this way, by automating the transport of the strand S to the strand cutter 56 in the preparation stage before the start of the production of pellets P, variation in the external force acting on the strand S is suppressed, and therefore variation in the diameter W of the strand S can be suppressed.

[0073] According to the pellet manufacturing apparatus 10, when there is a possibility that the tensile force acting on the strand S in the Y direction will become greater than necessary, the roller pair 46 is driven to rotate, thereby reducing the frictional force acting on the surface where the roller pair 46 contacts the strand S. This makes it possible to prevent the tensile force acting on the strand S from becoming greater than necessary.

[0074] According to the pellet manufacturing apparatus 10, the cooling section 60 cools the strand S, thereby promoting hardening of the strand S. This makes it possible to suppress deformation of the strand S during transport.

[0075] According to the pellet manufacturing apparatus 10, the cooling section 60 has an upstream shower 64. This allows the strand S, which is at a relatively high temperature immediately after being extruded from the extrusion section 20, to be hardened by cooling with the upstream shower 64, thereby preventing deformation of the strand S during transport.

[0076] According to the pellet manufacturing apparatus 10, the strand S is immersed in the water WT in the water tank 74 between the extrusion section 20 and the strand cutter 56. The temperature of the immersed strand S is reduced by heat exchange with the water WT. This allows the strand S to be cooled in a shorter time than when the strand S is cooled by air.

[0077] According to the pellet manufacturing apparatus 10, the water tank position detection unit 82 detects the position of the water tank 74 relative to the position of the extrusion unit 20. Then, the water tank position change unit 86 changes the position of the water tank 74 based on the detection result of the position of the water tank 74 detected by the water tank position detection unit 82. For example, if the position of the water tank 74 is too far from the position of the extrusion unit 20, the water tank 74 is moved closer to the extrusion unit 20. If the position of the water tank 74 is too close to the position of the extrusion unit 20, the water tank 74 is moved away from the extrusion unit 20. In this way, the distance between the extrusion unit 20 and the water tank 74 can be automatically managed.

[0078] According to the pellet manufacturing apparatus 10, the temperature change unit 104 changes the temperature of the water WT based on the temperature measured by the temperature measurement unit 102. For example, if the temperature of the water WT rises due to a change in the temperature of the environment in which the pellet manufacturing apparatus 10 is installed, the temperature of the water WT can be lowered using the cooler 109. If the temperature of the water WT drops, the temperature of the water WT can be raised using the heater 26. This makes it possible to manage the temperature of the water WT.

[0079] According to the pellet manufacturing apparatus 10, the support section 110 supports the strand S between the extrusion section 20 and the strand cutter 56. This makes it possible to prevent the strand S from being deformed during transport toward the strand cutter 56.

[0080] According to the pellet manufacturing apparatus 10, when the positions of the arm members 113, 123 in the Y and Z directions are changed relative to the strand S so that the support unit 110 can support the strand S, the support rollers 115, 125 come into contact with the strand S. Now, suppose that the positions of the arm members 113, 123 continue to be changed even after the support rollers 115, 125 come into contact with the strand S. In this case, the contact positions of the support rollers 115, 125 with the strand S change in the circumferential direction as the support rollers 115, 125 rotate. This reduces the frictional force acting on the strand S compared to a configuration in which the support rollers 115, 125 do not rotate, thereby preventing the strand S from being pulled by the support unit 110.

[0081] According to the pellet manufacturing apparatus 10, the measuring unit 130 measures the diameter W of the strand S in the X direction. The control unit 30 controls the rotation speed of the strand cutter 56 (upper roller 58A, lower roller 58B ( FIG. 3 )) based on the diameter W of the strand S in the X direction measured by the measuring unit 130. For example, if the diameter W of the strand S in the X direction is smaller than a preset diameter, the control unit 30 reduces the rotation speed of the upper roller 58A and the lower roller 58B. This reduces the tension acting on the strand S in the conveying direction, causing the diameter of the strand S in the X direction to approach the preset diameter.

[0082] On the other hand, if the diameter W of the strand S in the X direction is larger than the set diameter, the control unit 30 increases the rotation speed of the upper roller 58A and the lower roller 58B. This increases the tension acting in the Y direction, which is the transport direction of the strand S, and causes the diameter W of the strand S in the X direction to approach the set diameter (the diameter W becomes smaller). In this way, the diameter W of the strand S in the X direction can be made to approach the set diameter.

[0083] According to the pellet manufacturing method of the present embodiment, in a preparation stage before the production of pellets P, the gripping unit 42 grips the strand S extruded from the extrusion unit 20. The moving unit 50 moves the gripping unit 42. As a result, the strand S is automatically transported to the strand cutter 56. When production starts, the strand cutter 56 cuts the strand S, thereby producing a plurality of pellets P. In this way, by automating the transport of the strand S to the strand cutter 56 in the preparation stage before the start of pellet production P, variation in the external force acting on the strand S is suppressed, and therefore variation in the diameter W of the strand S can be suppressed.

[0084] According to the pellet manufacturing apparatus 10 or pellet manufacturing method of this embodiment, the transport of the strand S to the strand cutter 56 is automated in the preparation stage before the start of the production of the pellets P. Therefore, compared to a configuration in which a skilled engineer manually adjusts the operating conditions of the apparatus after observing the resin temperature and the state of the strand being discharged from the strand die, it is possible to optimize the operating conditions and improve the quality of the pellets P. By optimizing the operating conditions, it is possible to suppress the generation of waste in the early stages of molding the strand S. By improving the quality of the pellets P, it is possible to strand low-viscosity resins.

[0085] It goes without saying that the present disclosure is not limited to the above-described embodiment, and may be embodied in various different forms within the scope of the technical concept thereof. Hereinafter, various modifications of the pellet manufacturing apparatus 10 of this embodiment will be described. Components similar to those of the pellet manufacturing apparatus 10 will be assigned the same reference numerals and will not be described again.

[0086] <Modification 1> FIG. 12 shows a pellet manufacturing apparatus 140. The pellet manufacturing apparatus 140 has a base 142 instead of the water tank 74 and the water tank position changing unit 86 ( FIG. 1 ). In other words, the pellet manufacturing apparatus 140 is an apparatus in which the strand S is not immersed in water WT. The strand S extruded from the extrusion unit 20 is cooled by the water WT from the upstream shower 64 and then moved to the strand cutter 56 by the moving unit 50 while being gripped by the gripping unit 42. The strand S is further cooled by receiving the water WT from the downstream shower 66 while being moved by the moving unit 50. This allows the strand S to reach the strand cutter 56 in a hardened state, thereby suppressing deformation of the strand S during the preparation stage before production. In other words, similar to the pellet manufacturing apparatus 10 ( FIG. 1 ), variation in the diameter W of the strand S can be suppressed during the preparation stage before the start of pellet production. After production begins, the strand S is cut by the strand cutter 56 to produce pellets P. In this way, a pellet manufacturing apparatus 140 without a water tank 74 may be used.

[0087] <Modification 2> Fig. 13 shows a conveying unit 150. The conveying unit 150 is provided in place of the conveying unit 40 (Fig. 1) of the pellet manufacturing apparatus 10. The conveying unit 150 has a gripping unit 152 and a moving unit 50. The gripping unit 152 includes a support block 154, a movable block 156, and a block driving unit 158. The block driving unit 158 ​​includes a motor and gears. The operation of the block driving unit 158 ​​is controlled by the control unit 30 (Fig. 2).

[0088] The support block 154 is fixed to the carriage 54. A plurality of grooves 155 are formed in the support block 154. The grooves 155 are open upward in the Z direction and extend in the Y direction. When viewed from the Y direction, the grooves 155 are formed in an inverted trapezoid shape having one bottom surface 155A and two inclined surfaces 155B.

[0089] The movable block 156 is positioned above the support block 154 in the Z direction. The movable block 156 can be raised and lowered in the Z direction by a block driver 158. A plurality of grooves 157 are formed in the movable block 156. The grooves 157 are open downward in the Z direction and extend in the Y direction. When viewed from the Y direction, the grooves 157 are formed in a trapezoidal shape having one bottom surface 157A and two inclined surfaces 157B.

[0090] The strand S extruded from the extrusion unit 20 (FIG. 1) enters the multiple grooves 155 and is supported by the support block 154. Then, as the movable block 156 descends, the strand S is sandwiched between the bottom surface 155A, the inclined surface 155B, the bottom surface 157A, and the inclined surface 157B. In other words, the strand S is gripped by the gripping unit 152. The gripped strand S is moved in the Y direction by the moving unit 50. In this way, the gripping unit 152 may have a configuration in which the strand S is gripped by a non-rotating clip-like member.

[0091] <Other Modifications> The pellet manufacturing apparatus 10, 140 may not have the downstream shower 66. Furthermore, if the hardened state of the strand S extruded from the extrusion section 20 is such that the strand S can be moved (conveyed), the upstream shower 64 may not be provided. The pellet manufacturing apparatus 10, 140 may have a fixed water tank 74 and may not have the water tank position detection unit 82 or the water tank position change unit 86. The cooling unit 60 may not have the temperature measurement unit 102 or the temperature change unit 104. In other words, the temperature of the water WT in the water tank 74 does not need to be changed.

[0092] The pellet manufacturing apparatus 10, 140 may not be provided with the support unit 110. The support unit 110 may not have the arm members 113, 123 or the support rollers 115, 125. For example, a pad that is movable in the Z direction or a direction intersecting the Z direction may be provided, and the position of the pad may be changed to change the position of the strand S. The measuring unit 130 may not be provided, and the moving unit 50 may be moved at a preset speed. The cutting unit is not limited to one having a rotary blade 59 like the strand cutter 56, but may also be one having a blade that rises and falls in the Z direction.

[0093] DESCRIPTION OF SYMBOLS 2 Floor surface, 10 Pellet manufacturing device, 12 Operation panel, 14 Base, 14A Upper surface, 16 Upstream cutter, 17 Blade portion, 20 Extrusion portion, 22 Drive portion, 24 Cylinder, 25 Screw, 26 Heater, 27 Feeding portion, 28 Die, 28A Through hole, 30 Control portion, 33 Bus, 34 Memory, 40 Conveying portion, 42 Grip portion, 44 Support frame, 44A Vertical wall portion, 45A Bearing, 45B Bearing, 46 Roller pair, 47 Lower roller, 47A Outer circumferential surface, 48 Upper roller, 48A Outer circumferential surface, 49 Bearing drive portion, 49A Cam, 49B Motor, 50 Moving portion, 52 Guide rail, 54 Carriage, 56 Strand cutter, 57 Main body portion, 58 Strand receiving portion, 58A Upper roller, 58B Lower roller, 59 Rotary blade, 60 Cooling section, 62 Upper cooling section, 64 Upstream shower, 66 Downstream shower, 72 Lower cooling section, 74 Water tank, 75 Bottom wall section, 76 Side wall section, 76A Corner section, 76B Corner section, 77 Support frame, 82 Water tank position detection section, 83 Laser transmitter, 84 Laser receiver, 86 Water tank position change section, 87A Upstream drive roller, 87B Downstream drive roller, 87C Follower roller, 92 Roller lifting section, 93 Guide frame, 94 Guide frame, 95 Lifting frame, 96 Immersion roller, 102 Temperature measurement section, 104 Temperature change section, 105 Tank, 106 Pipe, 107 Pump, 108 Heater, 109 Cooler, 110 Support section, 112 Upstream support section, 113 Arm member, 114 Upstream drive unit, 115 Support roller, 115A Outer periphery, 116 Connecting pin, 122 Downstream support unit, 123 Arm member, 124 Downstream drive unit, 125 Support roller, 125A Outer periphery, 126 Connecting pin, 130 Measuring unit, 132 Camera, 134 Calculating unit, 140 Pellet manufacturing device, 142 Base, 150 Conveying unit, 152 Grip unit, 154 Support block, 155 Groove, 155A Bottom surface, 155B Inclined surface, 156 Movable block, 157 Groove, 157A Bottom surface, 157B Inclined surface, 158 Block drive unit, d Nip interval, d1 Interval, d2 Interval, L1 Length, LT Laser light, N Nip unit, P Pellets, R Molten resin, S Strand, S1 Strand, S2 strand, S3 strand, T1 temperature, T2 temperature, T3 temperature,W1 diameter, W2 diameter, W3 diameter, WT water,

Claims

1. A pellet manufacturing device comprising: an extrusion unit that extrudes molten resin material as a string-like strand; a gripping unit that grips the strand extruded from the extrusion unit; a movement unit that moves the gripping unit; and a cutting unit that cuts the strand transported by the movement of the gripping unit.

2. The pellet manufacturing apparatus according to claim 1, wherein the gripping section has a pair of rotatable rollers that pinch the strand.

3. The pellet manufacturing apparatus according to claim 1, further comprising a cooling section located between the extrusion section and the cutting section for cooling the strand.

4. The pellet manufacturing apparatus according to claim 3, wherein the cooling section has an upstream cooling section located between the extrusion section and the gripping section for cooling the strand.

5. A pellet manufacturing apparatus as described in claim 3, wherein the cooling section comprises: a storage tank for storing a liquid; and an immersion member located between the extrusion section and the cutting section for immersing the strand in the liquid.

6. The pellet manufacturing apparatus as described in claim 5, further comprising: a position detection unit that detects the position of the storage tank relative to the position of the extrusion unit; and a position change unit that changes the position of the storage tank based on the detection result of the position of the storage tank detected by the position detection unit.

7. The pellet manufacturing apparatus as described in claim 5, wherein the cooling section has: a temperature measuring section that measures the temperature of the liquid; and a temperature changing section that changes the temperature of the liquid based on the temperature measured by the temperature measuring section.

8. The pellet manufacturing apparatus according to claim 1, further comprising a support section positioned between the extrusion section and the cutting section and supporting the strand.

9. The pellet manufacturing apparatus according to claim 8, wherein the support portion comprises: a displacement member arranged so as to be able to change its position relative to the strand; and a support roller rotatably arranged on the displacement member and supporting the strand.

10. A pellet manufacturing apparatus as described in any one of claims 1 to 9, wherein the cutting unit has a pair of rotating members that clamp the strand and rotate while transporting the strand, and further comprises: a measuring unit that measures the diameter of the strand in a cross direction that intersects with the transport direction; and a control unit that controls the rotational speed of the pair of rotating members based on the diameter of the strand measured by the measuring unit.

11. A pellet manufacturing method comprising the following steps: (a) a step of extruding molten resin material as a string-like strand from an extrusion section; (b) a step of gripping the strand extruded from the extrusion section with a gripping section; (c) a step of transporting the strand to a cutting section by moving the gripping section with a moving section; and (d) a step of cutting the strand by the cutting section.

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