JP2011098498A - Resin feeder, injection molding machine, and resin molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin feeder which can uniformly carry out preheating of resin pellets in resin molding, an injection molding machine, and a method for manufacturing a resin molding. <P>SOLUTION: The resin feeder 5 conveys the resin pellets P and supplies the resin pellets P to the injection molding machine 3. The resin feeder 5 has a rotary cylinder 25 that extends in the conveyance direction (the axis A direction) of the resin pellets P, holds the resin pellets P inside, and set rotatably around a cylinder axis (A); a screw part 37 for moving the resin pellets P in the rotary cylinder 25 in the cylinder axis (A) direction; a band heater 41 heating the inside of the rotary cylinder 25; and a rotation control part 35 rotating the rotary cylinder 25 in the positive and reverse directions around the cylinder axis (A). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin supply device, an injection molding device, and a method for manufacturing a resin molded product.

  Conventionally, the technique of the following patent document 1 is known as a technique of this field. In the resin molding apparatus of this document, while the resin material in the conveyance path is fed by a feed screw, a high-temperature inert gas is passed through the conveyance path to preheat the resin material. Further, it is disclosed that the mechanism of softening the resin material by this preheating shortens the screw length of the molding machine and reduces the shearing action acting on the resin material from the screw.

JP-A-7-52185

  In resin molding, it may be necessary to preheat the resin pellets and dry them before they are put into a resin molding machine. However, if a method of rotating the feed screw as in Patent Document 1 within the central axis of the conveyance path is adopted, the resin pellets are fed forward while being collected in the lower part of the conveyance path by gravity. For this reason, unevenness is likely to occur in heating, for example, a part of the resin pellet is locally heated. If heating unevenness occurs, molding defects due to insufficient drying of the resin pellets occur, or smooth conveyance is hindered due to the weldability of the resin pellets that have been heated too much, resulting in poor supply of resin pellets. May occur.

  In view of the problems as described above, an object of the present invention is to provide a resin supply device, an injection molding device, and a method for manufacturing a resin molded product that can uniformly perform preheating of resin pellets in resin molding. .

  The resin supply apparatus of the present invention is a resin supply apparatus that conveys resin pellets and supplies the resin pellets to a resin molding machine, and extends in the conveyance direction of the resin pellets. A rotating cylinder provided rotatably, and a helical cylinder provided around the cylinder axis on the inner side of the rotating cylinder, and rotated around the cylinder axis together with the rotating cylinder to cause the resin pellets to move in the cylinder axis direction. And a rotation control unit that rotates the rotating cylinder in both forward and reverse directions around the cylinder axis.

  According to this resin supply device, the resin pellets to be conveyed are accommodated in the rotating cylinder and conveyed in the cylinder axis direction. Since the rotating cylinder is rotated in both forward and reverse directions around the cylinder axis, the resin pellets are oscillated in the rotating cylinder and conveyed while being stirred. Moreover, a resin pellet is moved to a cylinder axial direction by a screw part rotating with a rotation cylinder. Since the resin pellets are efficiently stirred as the rotating cylinder rotates forward and backward, the heat in the rotating cylinder by the heating means is uniformly applied to each particle of the resin pellets. Therefore, the preheating of the resin in the resin molding can be performed uniformly.

  The screw portion may extend in a spiral shape along the inner wall surface of the rotating cylinder. According to this configuration, since the screw portion extends along the inner wall surface and is located at the peripheral portion in the rotating cylinder shaft, the periphery of the rotating shaft can be hollow. Therefore, the resin pellets are more efficiently agitated along with the forward and reverse rotations of the rotating cylinder, and the preheating of the resin in the resin molding can be performed more uniformly.

  Further, the rotation control unit may repeatedly perform a cylinder rotation cycle for rotating the rotating cylinder so that a total rotation angle of forward rotation is larger than a total rotation angle of reverse rotation. According to this configuration, the resin pellets can be moved in the cylinder axis direction at every cylinder rotation cycle, and the conveyance of the resin pellets in the cylinder axis direction is realized.

  Specifically, the cylinder rotation cycle includes a reciprocating rotation step in which forward and reverse rotations of the rotating cylinder are alternately reciprocated at least once, and a forward rotation step in which normal rotation is performed after the reciprocating rotation step. It is good.

  The injection molding apparatus of the present invention includes any one of the above-described resin supply apparatuses, and an injection molding machine that obtains a resin molded product by injection molding the resin pellets supplied from the resin supply apparatus. It is characterized by. In this injection molding apparatus, the resin pellets that have been uniformly preheated can be smoothly supplied to the injection molding machine by any of the above-described resin supply apparatuses. Therefore, by supplying resin pellets that have been dried well to the injection molding machine, molding defects can be reduced and the quality of the molded product can be improved.

  The method for producing a resin molded product according to the present invention includes housing resin pellets inside a cylinder, heating the cylinder, and rotating the cylinder in both forward and reverse directions around a cylinder axis. A resin conveying step of conveying in the cylinder axis direction, and an injection molding step of introducing the resin pellets fed from the cylinder into the injection molding machine to obtain a resin molded product by injection molding. A screw portion is provided on the inner side of the body and is provided in a spiral shape around the cylinder axis so as to rotate around the cylinder axis together with the cylinder and move the resin pellets in the cylinder axis direction. And

  According to this manufacturing method, the conveyed resin pellet is accommodated in the cylinder and is conveyed in the cylinder axis direction. Then, since the cylinder is rotated in both forward and reverse directions around the cylinder axis, the resin pellet is oscillated in the cylinder and conveyed while being stirred. Moreover, a resin part is moved to a cylinder axial direction by a screw part rotating with a cylinder. Since the agitation of the resin pellet accompanying the forward / reverse rotation of the cylinder is efficiently performed, the heat in the cylinder by the heating means is uniformly applied to each particle of the resin pellet. Therefore, the preheating of the resin in the injection molding can be performed uniformly. As a result, well-dried resin pellets are smoothly supplied to the injection molding machine, molding defects can be reduced, and the quality of the molded product can be improved.

  ADVANTAGE OF THE INVENTION According to this invention, the resin supply apparatus, the injection molding apparatus, and the manufacturing method of a resin molded product which can perform uniformly the preheating of the resin pellet in resin molding can be provided.

It is sectional drawing which shows one Embodiment of the injection molding apparatus of this invention. It is a partially broken perspective view which shows the principal part of the resin supply apparatus of FIG. It is a disassembled perspective view which shows the principal part of the resin supply apparatus of FIG. (A)-(e) is sectional drawing which took and showed the state which the rotating cylinder and screw part of FIG. 1 rotate in the cross section orthogonal to the cylinder axis A direction. FIG. 2 is a cross-sectional view showing a rotating cylinder and a screw part in FIG. It is sectional drawing which shows the modification replaced with the screw part of FIG. It is a disassembled perspective view which shows the principal part of the resin supply apparatus of FIG.

  Hereinafter, preferred embodiments of a resin supply device, an injection molding device, and a method of manufacturing a resin molded product according to the present invention will be described in detail with reference to the drawings.

  As shown in FIG. 1, the injection molding apparatus 1 is an apparatus for manufacturing a resin product by an injection molding method. The injection molding apparatus 1 includes an injection molding machine 3 that performs product injection molding, and a resin supply device 5 that supplies resin pellets P to the injection molding machine 3 at a constant speed.

  The resin pellet P used here is mainly a commercially available cylindrical granular resin pellet, but may be a pulverized resin regenerated from a resin product, for example.

  The injection molding machine 3 is a known in-line screw type injection molding machine, and includes an injection unit 7 that melts and injects a resin, and a molding unit 9 that molds the injected resin with a mold. Granular resin pellets P are introduced into the injection unit 7 from the hopper 11. When the resin pellet P is bitten by the rotating screw 13, the resin pellet P receives heat from the surroundings while being sent forward, and the resin pellet P is softened and deformed by the shearing force from the inner wall surface of the heating cylinder 15. obtain. Further, the fiber dispersion of the resin proceeds by the swirling flow in the groove of the screw 13, and finally the molten resin having a uniform and good flow is prepared and prepared in front of the screw 13. Then, the molten resin is pushed forward by the advance of the screw 13, whereby the molten resin is injected from the nozzle 17 at the tip to the molding unit 9. The molding unit 9 has a mold and a mold clamping mechanism for clamping the mold, and a resin molded product molded by the mold and cooled and solidified is taken out as a product by opening the mold with the mold clamping mechanism.

  The resin supply device 5 is a device that transports the resin pellet P horizontally while heating it, and throws the resin pellet P into the hopper 11 of the injection molding machine 3 at a constant speed. The resin supply device 5 includes a cylindrical outer cylinder housing 21 that extends horizontally and a pellet introduction portion 23 provided at the rear end of the outer cylinder housing 21. A hopper 27 that opens upward in a trumpet shape is provided at the top of the pellet introducing portion 23. Resin pellets P are supplied from the hopper 27 to the resin supply device 5.

  Further, as shown in FIGS. 2 and 3, a rotating cylinder 25 having a cylindrical shape coaxial with the outer cylinder casing 21 is built in the outer cylinder casing 21. The resin pellet P supplied from the hopper 27 passes through the hollow portion inside the rotating cylinder 25 and is conveyed to the hopper 11 of the injection molding machine 3. That is, the hollow portion of the rotating cylinder 25 constitutes the transport path 26 for the resin pellet P. Specifically, the resin pellets P in the hopper 27 move downward in the pellet introduction part 23 by gravity and are introduced into the rotary cylinder 25 through the pellet inlet 25a provided on the rear end surface of the rotary cylinder 25. Is done. As will be described in detail later, the resin pellet P moves forward in the rotary cylinder 25 and falls from the pellet outlet 25b opened at the tip of the cylindrical surface of the rotary cylinder 25, and the outer cylinder housing The hopper 11 is charged through the pellet supply port 5 a opened at 21.

  The rotating cylinder 25 is supported by the outer cylinder casing 21 so as to be rotatable around a cylindrical axis A. A shaft 28 protruding rearward of the pellet introducing portion 23 is directly connected to the rear end surface of the rotating cylinder 25, and a pulley 29 is attached to the rear end portion of the shaft 28. A motor 31 is provided below the pellet introducing portion 23, and the motor 31 rotates the pulley 29 via the belt 33. In addition, the resin supply device 5 includes a rotation control unit 35 that transmits a drive signal to the motor 31 and controls the rotation of the motor 31. The rotation control unit 35 can rotate the motor 31 forward and backward by a drive signal. For example, a computer can be used as such a rotation control unit 35. With such a configuration, the rotating cylinder 25 rotates around the cylinder axis A in both the forward and reverse directions under the control of the rotation control unit 35.

  As shown in FIGS. 2 and 3, a screw portion 37 is installed inside the rotating cylinder 25 in a range from the pellet inlet 25 a to the pellet outlet 25 b. The screw portion 37 is a coil spring-like member that extends in a spiral around the cylinder axis A along the inner wall surface 25 c of the rotating cylinder 25. The screw part 37 is fixed to the rotating cylinder 25 and rotates around the cylinder axis A together with the rotating cylinder 25. Further, the screw portion 37 is inscribed in the inner wall surface 25c with almost no gap. As shown in FIG. 4, when viewed in parallel to the cylinder axis A, the screw portion 37 is predetermined from the inner wall surface 25c toward the cylinder axis A. Standing up at the height of

  Further, since the screw part 37 extends spirally along the inner wall surface 25c, the conveying path 26 inside the rotary cylinder 25 has a shape of a virtual cylinder 37s (FIG. 3) inscribed in the screw part 37. A hollow portion 39 is formed. Here, the screw part 37 is provided as a separate member from the rotating cylinder 25 and is detachably fixed to the rotating cylinder 25 by, for example, screwing. The screw portion 37 can be extracted from the rotating cylinder 25 in the direction of the cylinder axis A by releasing the fixation with the rotating cylinder 25. With this configuration, maintenance of the inner wall surface 25c of the rotating cylinder 25 and the screw portion 37 is facilitated. The screw portion 37 may be integrally formed on the inner wall surface 25c of the rotating cylinder 25.

  Due to the presence of the screw part 37, the screw part 37 is rotated together with the rotation of the rotary cylinder 25 around the cylinder axis A, and the resin pellet P moves in the direction of the cylinder axis A. In the following description, rotation of the rotating cylinder 25 in which the resin pellet P moves forward toward the pellet outlet 25b is referred to as “forward rotation”, and the rotating cylinder in which the resin pellet P moves backward toward the pellet inlet 25a. The rotation of the body 25 is referred to as “reverse rotation”. The rotating cylinder 25 swings and agitates the resin pellets P in the transport path 26 by repeating a rotation cycle set in advance by the rotation control unit 35.

  The rotation cycle is set such that the total rotation angle of the forward rotation is larger than the total rotation angle of the reverse rotation in one cycle. For example, the rotation cycle is set so as to include a reciprocating rotation step in which forward / reverse rotation of the rotating cylinder 25 is alternately reciprocated at least once, and a forward rotation step in which normal rotation is performed after the reciprocating rotation step. In this case, for example, the rotational speed of the rotating cylinder 25, the number of forward / reverse rotations of the rotating cylinder 25 in the reciprocating rotation step, the number of reciprocations in the reciprocating rotation step, and the number of rotations in the forward rotation step are set items. Become.

An example of a specific rotation cycle in this case is as follows. For example, each setting item can be set as follows: rotation speed = 3 rotations per second,
Number of forward rotations in the reciprocating rotation step = 1 rotation,
Number of reverse rotations in the reciprocating rotation step = 1 rotation,
Number of reciprocations in the reciprocating rotation step = 3 reciprocations,
Number of rotations in the normal rotation step = 2 rotations,
And so on. In this case, the rotating cylinder 25 repeats one forward rotation and one reverse rotation alternately at a rotation speed of 3 rotations per second without interposing a resting state. A series of rotational operations in which such forward and reverse alternating rotations are performed three times and then two forward rotations in the forward rotation step are further added is set as one cycle. According to such setting, the resin pellets P are transported forward at a desired speed as a result of repeating the forward and backward movements in the transport path 26 by repeating the rotation cycle.

  Further, the resin supply device 5 includes a band heater 41 arranged so as to be wound around the outer peripheral surface of the outer cylinder housing 21. Due to the heat generated by the band heater 41, the transport path 26 for the resin pellets P inside the rotating cylinder 25 is heated. The resin pellet P is transported through the transport path 26 while being heated and roasted by heat transfer from the inner wall surface 25c and heated air in the transport path 26. Accordingly, the resin pellets P discharged from the pellet outlet 25b have a certain high temperature, and the resin supply device 5 can supply the resin pellets P having a certain high temperature to the injection molding machine 3.

  Based on the above-described configuration of the injection molding apparatus 1, the resin pellets P are accommodated in the conveyance path 26 inside the rotary cylinder 25, the inside of the rotary cylinder 25 is heated, and the rotary cylinder 25 is forward and backward around the cylinder axis A. The resin feeding device 5 performs a resin transporting process for transporting the resin pellets P in the direction of the cylinder axis A while rotating in both directions. The injection molding machine 3 performs an injection molding process in which the resin pellets P delivered from the rotary cylinder 25 are introduced into the injection molding machine 3 and injection molded to obtain a resin molded product. Thus, in the injection molding apparatus 1, a resin molded product is manufactured by the resin conveying step and the injection molding step.

  Then, the effect which the injection molding apparatus 1 provided with the resin supply apparatus 5 show | plays is demonstrated.

  As described above, the resin supply device 5 conveys the resin pellets P in the rotating cylinder 25 while rotating the rotating cylinder 25 alternately forward and backward. As shown in FIGS. 4 (a) to 4 (e), by rotating the rotating cylinder 25 alternately forward and reverse, the resin pellets P in the rotating cylinder 25 are dragged by the inner wall surface 25c and rise / drop. Is repeated in the circumferential direction, and thus is carried and heated while being effectively swung and agitated in the rotating cylinder 25.

  Here, if the rotation direction of the rotating cylinder 25 is set to one direction, the mutual positions of the resin pellets P are unlikely to change, so the particles of the resin pellets P move in a relatively stationary group. Easy to do. In this case, with the softening of the surface of the resin pellet P particles, the particles are likely to be welded together to form a scour (pellet lump), and the resin pellet P may not be efficiently stirred.

  On the other hand, in this resin supply device 5, since the rotation direction of the rotating cylinder 25 is switched alternately between forward and reverse, each particle of the resin pellet P is caused by rocking and stirring in the rotating cylinder 25. It hardly stays at the same position on the inner wall surface 25c or the surface of the screw part 37 for a long time, and the resin pellet P is hardly welded to the inner wall surface 25c or the like. Moreover, since each particle | grain of the resin pellet P hardly contacts the same particle for a long time, time for the resin pellet P to weld is not given, and a pellet lump is hard to generate | occur | produce. Therefore, the resin pellets P are efficiently stirred.

  Further, since the screw part 37 extends spirally along the inner wall surface 25 c of the rotating cylinder 25, the screw part 37 is located at the peripheral edge of the transport path 26. Therefore, the shaft of the screw portion 37 does not exist in the vicinity of the cylinder axis A, and a hollow portion 39 is formed in the center of the conveyance path 26. Therefore, the rise and fall of the resin pellet P accompanying the forward and reverse rotation of the rotating cylinder 25 is not hindered by the shaft or the like, and as a result, the resin pellet P is more efficiently stirred.

  By such agitation of the resin pellet P, heat in the rotating cylinder 25 by the band heater 41 is uniformly applied to each particle of the resin pellet P, and the preheating of the resin pellet P can be performed uniformly. As a result, the resin pellets P that have been uniformly preheated can be supplied to the injection molding machine 3. Then, the resin pellets P that are well dried are supplied to the injection molding machine 3, so that molding defects are reduced and the quality of the molded product can be improved.

  Further, in heating the resin pellet P by the resin supply device 5, it is considered that the higher the temperature is, the closer the dried state of the resin pellet P is, and as a result, the effect of improving the quality of the molded product is high. That is, from the viewpoint of improving the quality of the molded product, the temperature of the resin pellet P heated by the resin supply device 5 is preferably higher. However, if the temperature of the resin pellet P becomes high, problems such as the softened resin pellet P being welded to the inner wall surface 25c of the rotating cylinder 25 and the resin pellets P being easily welded to each other are likely to occur.

  On the other hand, as described above, since the resin pellet P is efficiently stirred in the resin supply device 5, even when the resin pellet P is softened to some extent, the resin pellet P is hardly welded to the inner wall surface 25c. Since welding between the pellets hardly occurs, the temperature of the resin pellet P can be easily increased, and the effect of improving the quality of the molded product can be enhanced. For example, in this case, the base resin of the resin pellet P exceeds the softening point, and the resin pellet P can be heated to such a degree that it can be easily crushed when grasped with pliers or the like. For example, when the resin base material of the resin pellet P is a polypropylene resin, it can be heated to about 135 ° C.

  For example, when using resin pellets P based on polyamide resin or polycarbonate resin, it is essential to predry the resin pellets P before supplying them to the injection molding machine 3. In the case of using such resin pellets P, the resin supply device 5 can perform high-temperature drying immediately before plasticizing the resin pellets P, so that the drying effect is improved. Also, in other resins, the final drying temperature can be increased by about 20 to 30 ° C. from the conventional drying temperature, and since it can be dried at a uniform temperature without unevenness, molding trouble due to insufficient drying can be reduced. For example, in the case where a pulverized material of PET resin is used as the resin pellet, almost complete drying is possible by heating and conveying the resin supply device 5, and defective products in the molded product are reduced.

  Further, as shown in FIG. 5, when the lower half of the conveyance path 26 is viewed from above, the conveyance path 26 corresponds to the pitch of the screw portions 37 and a plurality of small chambers r <b> 1 arranged in the cylinder axis A direction. , R2, r3,..., Rn,. The resin pellets P are subdivided and stored in each small room rn. From this state, when forward and reverse rotation of the rotating cylinder 25 is performed, the hollow portion 39 (see FIGS. 2 to 4) is formed in the center of the transport path 26 as described above, so that the resin pellet P can easily jump to the adjacent small room by passing through the hollow portion 39 when rising and falling.

  Each time the forward / reverse rotation of the rotating cylinder 25 is repeated, the amount of the resin pellets P stored in the small chambers r1, r2, r3,... Is averaged. Therefore, the closer to the pellet outlet 25b, the smaller the amount of the resin pellets P is divided into the small chambers r1, r2, r3,. This means that by repeating the rotation cycle of the rotating cylinder 25, an accurate and constant amount of resin pellets P with small variations is discharged from the pellet supply port 5a. Therefore, the rotation speed of the rotating cylinder 25 can be accurately controlled by the motor 31 and the rotation control unit 35, and the supply speed of the resin pellet P from the pellet supply port 5a to the hopper 11 (per unit time). ) Can be controlled at a constant speed with high accuracy.

  As a result, the supply rate of the resin pellets P to the hopper 11 can be accurately matched to the consumption rate (consumption per unit time) of the resin pellets P in the injection molding machine 3. Therefore, there is no need for the high temperature resin pellets P to stay in the hopper 11, and the possibility that the resin pellets P are welded to the hopper 11 or the particles of the resin pellets P are welded to each other is reduced. Therefore, the possibility that the resin pellets P cannot be supplied due to the so-called bridge phenomenon can be reduced.

  In addition, since the particle shape of the commercially available resin pellet is cylindrical, if the small-sized injection molding machine 3 having a shallow groove of the screw 13 is used, if the resin pellet P at room temperature is supplied to the hopper 11, the resin pellet P Could not be bitten by the screw 13, and the resin pellet P could not be introduced into the heating cylinder 15. On the other hand, in the injection molding apparatus 1, since the heated and softened resin pellets P are supplied to the hopper 11, the resin pellets P are deformed into the heating cylinder 15 even when the groove of the screw 13 is somewhat shallow. Can be sent. As described above, the injection molding apparatus 1 can use the resin pellets P that cannot be conventionally used in the small injection molding machine 3.

  In addition, when the base resin of the resin pellet P is ABS resin, acrylic resin, polyamide (nylon) resin, etc., according to the conventional method, these resin pellets are dried with hot air for 3 to 6 hours at 80 ° C. It is performed in a dryer, and after being dried, it is supplied to an injection molding machine. Further, when the base resin of the resin pellet P is an engineering plastic such as polycarbonate resin, PPS, PBT, etc., according to the conventional method, after being dried at 120 ° C. under drying conditions for 4 to 8 hours, an injection molding machine To be supplied. At this time, it takes a long time to set a temperature within a safe range in order to avoid local oxidation and alteration due to thermal decomposition, and to uniformly dry the whole. On the other hand, since the injection molding apparatus 1 continuously supplies the resin pellets P to the injection molding machine 3 while heating them, it is not necessary to heat even unnecessary resin pellets that are not used, and the thermal efficiency is high.

  Moreover, since the resin pellet P can avoid local overheating by the rocking | fluctuation by the rotating cylinder 25, it can raise preset temperature. Thereby, it can dry from the surface to a deep place compared with the past. When the transport amount of the resin pellets P is large, it is necessary to optimize the set temperature according to the increase / decrease of the transport amount, such as increasing the set temperature because the temperature at the outlet is lowered. As a general temperature setting, the pellet surface temperature at the outlet of the resin supply device 5, that is, the supply port of the injection molding machine 3 is increased by 10 to 30 ° C. with respect to the set temperature in the hot air dryer of the conventional method. Is possible. It is possible to adjust the surface temperature of the resin pellet P discharged from the pellet supply port 5a by appropriately adjusting the output of the band heater 41 or appropriately adjusting the setting items of the rotation cycle in the rotation control unit 35. is there.

  The present invention is not limited to the embodiment described above. For example, in the embodiment, the coil spring-shaped screw portion 37 is employed as the axial conveying means, but instead of this, a screw portion 137 as shown in FIGS. 6 and 7 may be employed. The screw portion 137 includes a shaft 137a extending on the cylinder axis A and a spiral flight 137b installed around the shaft 137a.

  The screw portion 137 is fixed to the rotating cylinder 25 and rotates around the cylinder axis A together with the rotating cylinder 25. Further, the flight 137 b of the screw part 137 is circumscribed on the inner wall surface 25 c of the rotating cylinder 25. Here, the screw part 137 is provided as a separate member from the rotating cylinder 25 and is detachably fixed to the rotating cylinder 25 by, for example, screwing. The screw portion 137 can be removed from the rotating cylinder 25 in the direction of the cylinder axis A by releasing the fixation with the rotating cylinder 25, facilitating maintenance. Even if such a screw part 137 is used, the resin pellets P can be fed in the direction of the cylinder axis A by the rotation of the rotary cylinder 25.

DESCRIPTION OF SYMBOLS 1 ... Injection molding apparatus, 3 ... Injection molding machine (resin molding machine), 5 ... Resin supply apparatus, 25 ... Rotating cylinder, 25a ... Inner wall surface of rotating cylinder, 35 ... Rotation control part, 37 ... Screw part, 41 ... band heater (heating means), 137 ... screw part, A ... cylindrical shaft, P ... resin pellet.

Claims (6)

A resin supply device that conveys resin pellets and supplies the resin pellets to a resin molding machine,
A rotating cylinder that extends in the conveying direction of the resin pellets, accommodates the resin pellets inside, and is rotatably provided around a cylinder axis;
A screw part provided in a spiral shape around the cylinder axis inside the rotary cylinder and rotating around the cylinder axis together with the rotary cylinder and moving the resin pellet in the cylinder axis direction;
Heating means for heating the rotating cylinder;
A resin supply apparatus comprising: a rotation control unit configured to rotate the rotating cylinder body in both forward and reverse directions around the cylinder axis.   The resin supply device according to claim 1, wherein the screw portion extends spirally along an inner wall surface of the rotating cylinder. The rotation control unit
3. The resin according to claim 1, wherein a cylinder rotation cycle for rotating the rotating cylinder is repeatedly performed so that a total rotation angle of forward rotation is larger than a total rotation angle of reverse rotation. Feeding device. The cylinder rotation cycle is:
4. The resin supply according to claim 3, comprising: a reciprocating rotation step in which forward and reverse rotations of the rotating cylinder are alternately reciprocated at least once; and a forward rotation step in which normal rotation is performed after the reciprocating rotation step. apparatus. The resin supply device according to any one of claims 1 to 4,
An injection molding machine for obtaining a resin molded product by injection molding the resin pellets supplied from the resin supply device;
An injection molding apparatus comprising: Resin pellets are accommodated inside the cylinder, the resin pellet is conveyed in the cylinder axis direction while heating the cylinder and rotating the cylinder in both forward and reverse directions around the cylinder axis; and
An injection molding step of introducing the resin pellets fed from the cylindrical body into the injection molding machine to obtain a resin molded product by injection molding;
With
A screw part is provided inside the cylinder so as to spiral around the cylinder axis and rotate around the cylinder axis together with the cylinder to move the resin pellets in the cylinder axis direction. A method for producing a resin molded product characterized by the above.

Images