JP3418498B2 - Equipment for supplying resin raw materials to injection molding machines - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for supplying a resin raw material to an injection molding machine, and more particularly, to switching production of an injection molded article by exchanging a resin raw material. In this case, the present invention relates to a measure for preventing a resin material after production from being mixed into a resin material to start production. 2. Description of the Related Art Conventionally, for example, Japanese Unexamined Patent Publication No. 7-314488
As disclosed in Japanese Patent Laid-Open Publication No. H07-163, an air blow type removing device is installed at the end of the cylinder, and in the process of melting and injecting the resin raw material directly supplied from the hopper into the cylinder, the gap between the screw end and the cylinder is removed. There is known an injection molding machine in which resin dust clogged in a gap is taken out of a cylinder by a reversing operation of a screw, and the above-mentioned removing device is operated to blow off the resin dust. On the other hand, resin materials are not supplied directly from the hopper into the cylinder as described above. For example, different types of resin materials (a resin material serving as a main material of an injection molded product and a coloring material for coloring the same) are used. There is also an injection molding machine in which mixing is carried out in the course of conveying the raw material conveying system, and the mixed raw material is supplied to a cylinder. [0004] When a resin material is supplied to a cylinder of an injection molding machine via a material conveying system, as in the latter case, the resin material which has been previously produced is charged with static electricity or the like. If it remains on the raw material transport system due to this, it may be mixed into the resin raw material during the subsequent production and adversely affect the quality, and some measures are desired. [0005] Therefore, it is conceivable to install a vibrating device in the raw material transporting system to remove the resin material remaining on the raw material, and to install the vibrating device over the entire raw material transporting system, the equipment cost is increased. Will soar. [0006] On the other hand, the installation of the former removing device is different from the application site, that is, in the former case, the first is to remove the resin debris in relation to the reversing operation of the screw of the injection molding machine. However, it is difficult to apply this as it is to the raw material transport system. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to remove a resin material adhered and remaining on a material transporting system path by a simple and inexpensive means, thereby providing a new resin material. It is an object of the present invention to prevent old resin raw materials from being mixed into the product and to effectively prevent the occurrence of defects in injection molded products. [0008] In order to achieve the above object, according to a first aspect of the present invention, there is provided a raw material transport system for transporting a resin raw material and supplying it to an injection molding machine. It is assumed that a resin raw material supply device to the injection molding machine is used. Then, pressurized air supply means for supplying pressurized air into the raw material transport system is connected to the raw material transport system. And
An air introduction pipe connected to the pressurized air supply means at a plurality of locations in the conveyance direction of the raw material conveyance system; an opening / closing means interposed between the air introduction pipes to open and close the air introduction pipes; When a new type of resin material is replaced with another type of resin material instead of the preceding type of resin material for the conveyance path, the preceding type resin material remaining in the material conveyance path is sequentially transferred from the upstream side of the material conveyance path. Control means for controlling the opening / closing means of each of the air introduction pipes so as to be scattered with a time difference. According to the first aspect of the present invention, the old resin raw material adhering and remaining in the raw material transport system due to static electricity or the like is replaced with another type of resin material in the raw material transport system in place of the preceding resin raw material. When a new resin material is to be replaced, the compressed air is forcibly blown off from the upstream side of the raw material transport system by the pressurized air for each air introduction pipe that is opened and closed with a time difference from the upstream side of the raw material transport system. It is scattered to the downstream side of the transport path and collected. Therefore, the old resin raw material is not mixed with the new resin raw material supplied to the injection molding machine, and defects such as different colors and materials are not generated in the injection molded product. In addition, it is only necessary to provide a simple structure in which pressurized air is supplied from a plurality of points in the conveying direction of the raw material conveying system via the air introduction pipe, and the raw material resin is sieved throughout the entire raw material conveying system. The pressurized air supply means is simpler and less expensive than when a dropping vibration device is installed. Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 show a resin raw material supply apparatus according to an embodiment of the present invention.
Is configured to supply a resin raw material to the injection molding machine 3 via a raw material conveying system path 5. The resin raw material supply device 1 includes a first raw material tank 7 for supplying a pellet-shaped resin material such as polypropylene as a resin raw material to the raw material transport system 5 at an upstream end of the raw material transport system 5. I have. Instead of polypropylene, other types of pellet-like resin materials such as polyvinyl chloride are exchangeably charged into the first raw material tank 7. A feed cylinder 11 as a casing having a feed screw 9 having a shaft extending in the horizontal direction is connected to the bottom of the first raw material tank 7 on the downstream side of the raw material transporting path 5. I have. A feed screw 9 is provided at one axial end (left side in the figure) of the feed cylinder 11.
There is provided a motor 13 for rotating the motor 13 around its axis. The feed screw 9 and the motor 13 constitute a feed device 12 that feeds the resin material falling from the first raw material tank 7 downstream (from left to right in the figure) of the raw material transport system path 5. ing. At the bottom right end of the feed cylinder 11,
The upstream end of the first transfer pipe 5a of the raw material transfer path 5 is connected. The downstream end of the first transport pipe 5a is
a, which is connected to a first hopper 15 having a first vacuum generator 14 for generating a negative pressure (vacuum) in the first transfer pipe 9 and feeds the resin material fed from the feed cylinder 11 by the feed screw 9 to the first transfer pipe. The suction is performed up to the first hopper 15 via 5a. A dryer 17 is provided at the bottom of the first hopper 15.
The resin material sucked by the first vacuum generator 14 is dropped from the first hopper 15 to the dryer 17 to be dried. The upstream end of the second transport pipe 5b of the raw material transport path 5 is connected to the bottom of the dryer 17. The downstream end of the second transfer pipe 5b is connected to a second hopper 21 provided with a second vacuum generator 19 for generating a negative pressure in the second transfer pipe 5b.
, And sucks the resin material dried by the dryer 17 to the second hopper 21 via the second transport pipe 5b. The second hopper 21 includes a cylindrical tank portion 21a located on the upper side and a funnel-shaped hopper portion 21b located on the lower side. And the second
A second material tank 23 is provided on the bottom of the hopper 21 (the lower surface of the hopper 21 b) via the third transfer pipe 5 c of the material transfer path 5.
Are connected. The upper end of the second raw material tank 23 is connected to a downstream end of a fourth transport pipe 5d of the raw material transport system path 5. The upstream end of the fourth transport pipe 5d is connected to the bottom of a third raw material tank 25 that stores a pellet-shaped coloring material as a resin raw material for coloring the resin material. Between the second raw material tank 23 and the third raw material tank 25, the coloring material in the third raw material tank 25 is
A suction device 27 for transferring by suction through the transfer pipe 5d is provided. The coloring material in the third raw material tank 25 is
The upstream end of the fourth transport pipe 5d can be supplied via an open / close valve (not shown) that can be opened and closed.
The suction amount (supply amount) of the coloring material is kept uniform. Into the second raw material tank 23, the resin material sucked to the second hopper 21 and dropped from the bottom thereof and supplied, and the third raw material tank 25 sucked by the suction device 27 and supplied. A stirrer (not shown) for stirring the colorant is provided therein. The mixed raw material (resin material and coloring material) stirred by the stirrer is provided as a resin raw material to the injection molding machine 3. At the bottom of the second raw material tank 23 (stirrer), a cylinder 33 for injecting the resin material into a chamber (not shown) of an injection molding machine 3 for molding an injection molded product having a desired shape from the resin material. Is the fifth transfer pipe 5e of the raw material transfer path 5
It is provided continuously through. The cylinder 33 is configured as an injection unit 35 internally provided with a kneading screw (not shown) having a shaft extending in the horizontal direction.
The resin raw material (mixed raw material) falling from the second raw material tank 23 is heated and melted by a motor 37 provided at one axial end (left side in the figure) of No. 3, and the melted resin raw material is kneaded by a kneading screw. The injection is performed into the chamber of the injection molding machine 3. In this case, the first raw material tank 7,
Feed cylinder 11 (feed screw 9), first hopper 15
(First vacuum generator 14), dryer 17, second hopper 21
The (second vacuum generator 19), the second raw material tank 23 (stirrer), the third raw material tank 25, the suction device 27, and the transport pipes 5a to 5e constitute the resin raw material supply device 1. As a characteristic part of the present invention, a pressurized air supply means 41 for supplying pressurized air into the raw material transport system 5 is provided in the resin raw material supply device 1 (raw material transport system 5).
Is connected. The pressurized air supply means 41 includes a first air introduction pipe 45 whose upstream end is connected to an air pump 43. The downstream end of the first air introduction pipe 45 is connected to the tank 21a of the second hopper 21 via a first opening / closing valve 47 as opening / closing means. The upstream end of the second air introduction pipe 49 is connected to the first air introduction pipe 45 upstream of the first opening / closing valve 47.
9 is connected to the hopper 21b of the second hopper 21 via a second on-off valve 51 (opening / closing means). The first air introduction pipe 45 upstream of the first on-off valve 47 and downstream of the second air introduction pipe 49 has a third
The upstream end of the air introduction pipe 53 is connected, and the downstream end of the third air introduction pipe 53 is connected to the downstream side of the suction device 27 via a third opening / closing valve 55 (opening / closing means). Further, the first air introduction pipe 4 upstream of the second air introduction pipe 49 is provided.
5 is connected to the upstream end of a fourth air introduction pipe 57, and the downstream end of the fourth air introduction pipe 57 is connected to the third raw material tank 25.
Is connected via a fourth opening / closing valve 59 (opening / closing means). The first to fourth on-off valves 47, 51, 55, 59
Are controlled to open and close with a time lag by a control device 61 as control means.
When the air pumps 51, 55, and 59 are opened, the pressurized air from the air pump 43 is appropriately supplied to the downstream side to supply the second hopper 21 (the tank 21a and the hopper 21b), the suction device 27 and the third
First to fourth air introduction pipes 45, 49, 53 in the conveying direction of the raw material conveying path 5 so as to forcibly blow away the resin raw material (resin material and coloring material) attached to the raw material tank 25 and the like by static electricity or the like. , 57 are controlled. On the other hand, the first to fourth air introduction pipes 45,
49,53,57 are on-off valves 47,51,55,59
Is controlled so as to prohibit the supply of pressurized air when the valve is closed. The upstream end of the fifth air introduction pipe 63 is connected to the first air introduction pipe 45 upstream of the fourth air introduction pipe 57. The fifth air introduction pipe 63 is provided with a fifth on-off valve 65 in the middle thereof, and the downstream side of the fifth on-off valve 65 is branched into two. A downstream end, the feed cylinder 11 of the feeding axial end feeding portion directly toward the vicinity of feeding cylinder 11 the pressurized air inlet port 63a for supplying pressurized air into the screw 9, feed cylinder as 63b for these branches 11 are open near both ends in the axial direction.
The fifth opening / closing valve 65 is opened / closed by an opening / closing operation switch (not shown). When the fifth opening / closing valve 65 is opened, pressurized air from the air pump 43 is sent to the vicinity of one axial end of the screw 9. First pressurized air inlet 63
a (left side in FIG. 2) and the second pressurized air inlet 63b (left side in FIG. 2) near the other end in the axial direction, and adhere to and remain on both ends of the feed screw 9 in the axial direction. The resin material (resin material) is forcibly blown off. On the other hand, when the fifth on-off valve 65 is closed, the supply of pressurized air from both pressurized air introduction ports 63a and 63b is prohibited. In this case, when the fifth on-off valve 65 is opened, the feed screw 9 is rotated by the motor 13 so that the resin raw material adhering and remaining on both ends in the axial direction of the feed screw 9 can be smoothly blown off. Next, for the raw material transporting path 5, a new resin material such as a pellet-shaped polyvinyl chloride is replaced by a new one instead of the pellet-shaped resin material such as the preceding type of polypropylene, and the type of the coloring material is also changed. Opening / closing control of the first to fourth opening / closing valves 47, 51, 55, 59 by the control device 61 when newly replacing, that is, replacing with a resin material in which a new resin material (polyvinyl chloride) and a new coloring material are combined. Will be described based on the time chart shown in FIG. 3, and the opening and closing operation of the fifth on-off valve 65 will be described. In this case, the opening / closing control or opening / closing operation of each of the on-off valves 47, 51, 55, 59, 65 is performed before the replacement with another kind of resin raw material such as new polyvinyl chloride and the preceding type is placed in the raw material conveying system 5. After the resin material such as polypropylene has been used up. First, the preceding kind of resin material (resin material) adhering and remaining due to static electricity or the like is scattered and collected on the upstream side of the material transfer system path 5. That is, the fifth opening / closing valve 65 is opened by the opening / closing operation switch, and the motor 13 is driven to rotate the feed screw 9. Thus, first toward the vicinity of both axial ends of the feed screw 9, the second pressurized air inlet 63a, 63b pressurized air is supplied directly into the feed cylinder 11 from the axial direction of the feed screw 9 The screw 9 feeds the preceding kind of resin material remaining on both ends.
Can be efficiently blown off by the pressurized air in combination with the rotation and can be scattered and supplied to the downstream side of the first transport pipe 5a. The preceding type of resin material fed to the downstream side of the first transport pipe 5a is The first hopper 15, the dryer 17, the second hopper 21, the second raw material tank 23, and the injection unit 35 according to the resin transport system path 5.
And is scattered and collected by the injection molding machine 3. In this case, the fifth
The opening time and the number of times of the opening / closing valve 65 are arbitrary, but are performed twice at intervals of about ten and several seconds. On the other hand, the scattering recovery of the preceding type of resin raw material adhering and remaining on the downstream side of the raw material transporting path 5 is performed in synchronization with the scattering recovery on the upstream side of the raw material transporting path 5. That is, according to the time chart shown in FIG. 3, first, the first opening / closing valve 47 is opened to open the tank portion 2 of the second hopper 21 at the most upstream position on the downstream side of the raw material conveying system path 5.
1a, pressurized air is introduced through the first air introduction pipe 45,
The resin material adhering to the tank portion 21a due to static electricity or the like is blown off and scattered and fed to the hopper portion 21b side, and is closed after a lapse of a predetermined time (ten and several seconds). After the first on-off valve 47 is closed, the second on-off valve 51 is immediately opened, and the tank portion 21 of the second hopper 21 is opened.
a Pressurized air is introduced into the hopper 21b immediately downstream from the hopper 21b through the second air introduction pipe 49, and the resin material remaining on the hopper 21b is blown off by static electricity or the like, and is blown to the second material tank 23 side. It is scattered and fed, and is closed after a lapse of a predetermined time. After the closing of the second on-off valve 51, the third on-off valve 55 is immediately opened, and pressurized air is introduced to the downstream side of the suction device 27 through the third air introduction pipe 53. The coloring material adhered and remaining on the side is blown away by the static electricity or the like, and is scattered and fed to the second raw material tank 23 side. After the third on-off valve 55 is closed, the fourth on-off valve 59 is immediately opened, and pressurized air is introduced into the second raw material tank 23 via the fourth air introduction pipe 57, and the second raw material tank Residual raw material adhered and left to the nozzle 23 is blown off and scattered and fed to the injection unit 35 side, and the same is closed after a lapse of a predetermined time. In this case, the first to fourth on-off valves 47, 5
The opening / closing control of 1, 55, 59 is performed twice in accordance with the time chart of FIG. 3, and together with the scattering recovery on the upstream side of the raw material transport path 5, the preceding species of the preceding species on the downstream side of the raw material transport path 5 are combined. The resin material is reliably scattered and collected, and the preceding type resin material is reliably scattered and collected up to the injection molding machine 3. In this case, the first to fourth air introduction pipes 45, 49, 53, 57
The supply timings of the pressurized air from the feed passages are not overlapped with each other, that is, the raw material transport system passage is performed twice in the order from the first introduction pipe 45 to the second, third, and fourth air introduction pipes 49, 53, and 57. 5. As a result, the preceding kind of resin raw material (mixed raw material obtained by mixing a pellet-like resin material such as polypropylene and an old coloring material) remaining and attached to the raw material transporting path 5 due to static electricity or the like is removed from the upstream side. The material is forcibly blown off from the inside of the raw material transport system path 5 by the pressurized air supplied with a time difference in order, and is scattered and collected on the injection molding machine 3 side.
Therefore, another kind of new pellet-shaped resin material such as polyvinyl chloride supplied to the first raw material tank 7 and the third
Even if the raw material tank 25 is replaced with a resin material obtained by combining a new coloring material supplied to the second raw material tank 23 via the fourth conveying pipe 5d by the suction device 27 with the suction device 27, the new resin raw material is replaced with a resin of the preceding type. The raw material does not mix in the raw material transport system path 5, and it is possible to prevent the occurrence of defects in the injection molded product molded by the injection molding machine 3. Further, the pressurized air supply means 41 is provided at a plurality of locations in the transport direction of the raw material transport system path 5 with the first to fifth on-off valves 4.
It has a simple configuration in which pressurized air is supplied from the first to fifth air introduction pipes 45, 49, 53, 57, 63 with appropriate time lags via 7, 51, 55, 59, 65, and the raw material transport system The pressurized air supply means 41 can be provided simply and inexpensively as compared with the case where a vibration device or the like for sifting the raw material resin is installed over the entire area. It should be noted that the present invention is not limited to the above embodiment, but includes various other modifications. For example, in the above-described embodiment, the pressurized air is supplied to the feed cylinder 11 at the bottom of the first raw material tank 7 from the pressurized air introduction ports 63a and 63b opened near both ends in the axial direction of the feed screw 9. The pressurized air introduction port is opened only at one end near the axial end of the feed screw and near the other end, and the pressurized air is directly fed into the feed cylinder toward one axial end of the screw. It may be supplied only by Further, in the above-described embodiment, the case where the resin material is newly replaced with a combination of the type of the resin material and the type of the colorant has been described. However, only the type of the resin material or only the type of the colorant is replaced. May be used, in particular,
In the case where only the type of the coloring material is newly replaced, the preceding type of resin raw material may be scattered by the pressurized air only on the downstream side of the raw material transport system path.
Only the on / off control of the on / off valve is performed. Further, in the above embodiment it has been performed by opening and closing control twice of the first to fourth on-off valve 47,51,55,59, and not the particular number of opening and closing control is defined, For example, the number of times of opening / closing control may be one as long as the opening time during which the pressurized air is sufficiently supplied, and the opening / closing of the first to fourth opening / closing valves depending on the structure on the downstream side of the raw material transport system path. It goes without saying that the control may be repeated three or more times. On the other hand, the opening / closing operation of the fifth opening / closing valve 65 is not limited to two times, and is similarly performed once or three times.
Needless to say, it may be repeated more than once. As described above, according to the apparatus for supplying a resin raw material to the injection molding machine according to the first aspect of the present invention, the opening / closing means of the air introduction pipe is opened / closed with a time lag from the upstream side of the raw material conveying system. Controlling and forcibly blowing off the old resin raw material remaining in the raw material transport system from the upstream side of the raw material transport system and collecting it scattered downstream, thereby mixing the old resin raw material with the new resin raw material And the occurrence of defective injection molded articles can be prevented. In addition, the pressurized air supply means can be provided simply and inexpensively by connecting the air introduction pipe to the raw material conveying system path via the openable and closable controllable open / close means to constitute the pressurized air supply means. [0040]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an overall configuration of a resin raw material supply device according to an embodiment of the present invention. FIG. 2 is a vertical sectional side view of a feed cylinder. FIG. 3 is a time chart illustrating a supply timing of pressurized air depending on a time difference between first to fourth on-off valves. [EXPLANATION OF SYMBOLS] 3 injection molding machine 5 material conveying system path 7 first material tank (material tank) 9 feed screw 11 feeding the cylinder (casing) 41 pressurized air supply means 45,49,53,57,63 first To fifth air introduction pipe (air introduction pipe) 47, 51, 55, 59 first to fourth opening / closing valves (opening / closing means) 61 control device (control means)

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuo Matsuda 2-31-25 Kabeminami, Asakita-ku, Hiroshima-shi, Hiroshima Prefecture Nishikawa Chemical Co., Ltd. (56) References JP-A-7-40416 JP-A 7-60794 (JP, A) JP-A 7-1444 (JP, A) JP-A 52-77377 (JP, A) JP-A 64-44108 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B29C 31/00-31/10 B29C 45/00-45/84

Claims (1)

(1) An apparatus for supplying a resin raw material to an injection molding machine provided with a raw material conveyance system for conveying a resin raw material and supplying the resin raw material to the injection molding machine, wherein: The system path is connected to pressurized air supply means for supplying pressurized air into the material transfer path, and the pressurized air supply means is connected to the air connected to a plurality of points in the transfer direction of the material transfer path. An inlet pipe, an opening / closing means interposed between the air inlet pipes for opening and closing the air inlet pipes, and when replacing the preceding raw material for the raw material transfer path with another type of resin raw material. Control means for controlling the opening and closing means of each of the air introduction pipes with a time difference so as to sequentially scatter the preceding kind of resin raw material remaining in the raw material transfer path from the upstream side of the raw material transfer path. An apparatus for supplying a resin raw material to an injection molding machine .