JPH02178010A - Injection molder - Google Patents

Abstract

PURPOSE:To meter respective amount of resin required for every cavity by a method wherein plasticized resin is injected so as to be sent in a plurality of metering cylinders in order to move plungers in the respective metering cylinders until the cubic contents of the respective metering cylinders reach the cubic contents corresponding to the cubic contents of a plurality of the cavities. CONSTITUTION:When resin plasticized by a plasticizing device 20 is injected through the path 32 of a fixed platen 30, and the respective paths 37 of a rotary platen 34 so as to be sent to respective cylinders 35, the respective cylinders 35 are moved backwards to respective adjusting screws 43 side as the resin flows in the respective cylinders 35 so as to be stopped by abutting against the respective adjusting screws 43. At that time, since the amounts of resin to be injected in respective cavities 53a, 53b... are expressed by (the extended length of a movable rod 41 minus the projected lengths of the respective adjusting screws 43 beyond the edge face 42a of a pressing member 42)X(area of each cylinder 35), the injection amounts, which respectively correspond to the respective cavities 53a, 53b..., can be metered by adjusting the projected lengths of the respective adjusting screws 43 beyond the edge face 42a of the pressing member 42.

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention relates to an injection molding machine, and particularly relates to an injection molding machine in which 'fV
The present invention relates to an injection molding machine having several cavities.

"Prior Art" Conventionally, as this type of injection molding machine, the one shown in FIG. 6 has been known.

A heating cylinder 2 is provided below a hopper 1 for supplying resin P, and heaters 3...
is wound, and a screw 4 is provided inside the heating cylinder 2 so as to be movable back and forth. The screw 4 is rotated by a hydraulic motor or the like and moved forward by a hydraulic cylinder or the like, and a backflow prevention ring 5 is provided at the tip of the screw 4 so as to be movable back and forth. A nozzle 6 in which a through hole 6a is formed is provided at the tip of the heating cylinder 2. A mold 7 consisting of a fixed mold 8 and a movable mold 9 is placed at a position facing this nozzle 6.
is installed, the tip of the nozzle 6 is brought into contact with one end surface of the fixed mold 8, and the sprue 1 of the fixed mold 8 is connected to the through hole 6a.
0 are communicated with each other. The sprue lO is branched in the middle to form cavities 11, . It opens at 12.

In the injection molding machine configured as described above, when the screw 4 is rotated, the resin in the hopper 1 is plasticized and passes between the backflow prevention ring 5 and the screw 4 to form the tip 2a in the heating cylinder 2. is stored in In this case, as the plasticized resin is stored, the screw 4 is retracted,
Weighing is performed based on this amount of retreat. When the tip portion 2a is filled with an amount corresponding to the cavity 11.12, the rotation of the screw 4 is stopped.

Next, when the screw L-4 is moved forward, the rear end surface of the backflow prevention ring 5 comes into close contact with the screw 4, and the plasticized resin is injected from the through hole 6a of the nozzle 6, and the sprue lO
through which the cavity 11.12 of the mold 7 is filled.

"Problem to be Solved by the Invention" By the way, in the above injection molding machine, even if the resin plasticized and measured by the heating cylinder 2 and the screw 4 is injected from the through hole 6a of the nozzle 6, the resin will not reach the cavity. 11
The filling of the resin into the cavity 12 is not completed at the same time.

That is, when filling of the resin into the cavity 11 with a small capacity is completed, there is still a portion of the cavity 12 with a large capacity that is not filled. For this reason, the pressurizing conditions, cooling time, etc., differ between the resin in the cavity 11 and the resin in the cavity 12, resulting in problems such as the formation of a bubble in the resin in the cavity 11.

As a way to solve this problem, cavity 11.1
It is conceivable to provide the same number of heating cylinders 2 and screws 4 as the number of heating cylinders 2 (that is, two), to perform metering according to the cavities 11 and 12 with each of these, and to inject at the same time. However, this method has the problem that the apparatus becomes large-scale and therefore expensive.

This invention was made in view of the above circumstances, and its purpose is to be able to measure resin into a number of cavities with different capacities, and to complete injection of resin into each cavity at the same time. Our goal is to provide injection molding machines that can.

"Means for Solving the Problem" In order to achieve the above object, the injection molding machine of the present invention has the following features:
A fixed plate is provided between a plasticizing device that plasticizes the resin and a mold in which a plurality of beef bits are provided, and a rotary plate is provided within the fixed plate so as to be rotatable around an axis. A plurality of measuring cylinders extending parallel to the axis of the rotary disk and opening into the fixed plate are provided in the rotary disk so as to be able to communicate with the plasticizing device and each cavity, and a plunger is installed in each measuring cylinder as a shaft. The measuring cylinder can be moved reciprocally in the direction, and when it moves backward, the capacity of the measuring cylinder is provided like the above-mentioned cavity, and it is pressed by the injection pressure of the resin and comes into close contact with the fixed plate, so that the fixed plate and the rotary plate slide. A sealing member is provided to prevent resin leakage from the surface, and a moving means is further provided to simultaneously move the plungers forward.

"Function J" In the injection molding machine of this invention, the plasticizing device and the measuring cylinders provided on the rotary disk are communicated, and the resin plasticized by the plasticizing device is injected into the plurality of measuring cylinders. Upon feeding, the plunger within each metering cylinder is moved until the volume of each metering cylinder corresponds to the capacity of a plurality of cavities in the mold provided for each metering cylinder, thereby: A required amount of resin is measured for each cavity.The rotary disk is rotated to communicate each measuring cylinder with each cavity, and each plunger is moved forward by a moving means to measure the amount of resin. By pressurizing the resin measured in a shilling, the resin is injected into each cavity and into the metered cylinder, and the sole member is pressed by the injection pressure of the resin and comes into close contact with the fixed plate. It is possible to prevent resin leakage from the sliding surfaces.

Embodiment A first embodiment of the injection molding machine of the present invention will be described below with reference to FIGS. 1 to 4.

In these figures, reference numeral 20 denotes a plasticizing device,
It includes a heating cylinder 21 and a screw 22 provided inside the heating cylinder 21 so as to be movable back and forth. The scrub J knee 22 is rotated by a hydraulic motor or the like and moved forward by a hydraulic cylinder or the like. Reference numeral 30 denotes a cylindrical fixed plate, and an annular recess 31 is formed in an end surface 30a of the fixed plate 30. The fixed platen 30 also includes an end surface 3.
A passage 32 communicating from Oa to the circumferential surface 31a of the recess 31 is formed. The passage 32 includes an introduction passage 32a formed linearly in a direction perpendicular to the end surface 30a, an annular passage 32b branched from the introduction passage 32a and formed in a circular shape when viewed from the end surface 30a side, and an annular passage 32b formed in a circular shape when viewed from the end surface 30a side. A plurality of branch passages 32 each having one end open to the passage 32b and the other end opening to the recess 31.
It is composed of c... The introduction passage 32a is connected to the plasticizing device 20. Furthermore, fixed plate 30
A plurality of through holes 33 . . . communicating from the bottom surface 31 b of the recess 31 to the end surface 30 b are formed in the recess 31 . Each through hole 33
are arranged at equal intervals on the same circumference when viewed from the end surface 30a side.

A cylindrical rotary disk 34 is fitted into the recess 31 of the fixed plate 30 so as to be rotatable about the support shaft 30c of the fixed plate 30, and one end surface 34a of the rotary disk 34 and the recess As shown in FIG. 3
In order to rotate 4 smoothly, some clearance S,
, S, are provided. The rotary disk 34 has a bottom surface 3 of the recess 31 extending through it in parallel with the support shaft portion 30c.
The same number of cylinders (measuring cylinders) 35 . They are arranged at equal intervals on a circumference with the same diameter as the circumference of the circumference. The recess 31 of each 7 linter 35
The part opening to the bottom surface 31b is formed to have a large diameter,
A cylindrical seal member 36 is fitted into the large diameter portion 35a so as to be slidable in the axial direction. The diameter and height of this seal member 36 are set to be the same as the large diameter portion, and an injection hole 36a is formed in the center portion to penetrate in the axial direction.

The injection hole 36a is formed to have a smaller diameter than the cylinder 35JJ6 and the through hole 33, and its axis is aligned with the cylinder 3.
5 axis. And this seal member 3
6 is pressed by the injection pressure of the resin injected into the cylinder 35 and comes into close contact with the bottom surface 31b of the recess 31, thereby preventing resin leakage from the sliding surfaces of the fixed plate 30 and the rotary plate 34. It has become.

Further, the rotary disk 34 is formed with a plurality of passages 37 communicating from each cylinder 35 to the outer circumferential surface 34c. As shown in FIG. 2, a movable rod 3 of a hydraulic cylinder 38 whose base end is pivotally connected to a fixed portion is mounted on the rotary disk 34.
8a is pivotally mounted, and the rotary disk 34 is rotated by this hydraulic cylinder 38. Then, as shown in FIG. 2, when the movable rod 38a extends, the rotary disk 34 rotates in the X direction and is fixed to each passage 37! ff
When each branch passage 32c of the 30 passages 32 communicates with each other, each cylinder 35 and the 6 through holes 3 of the fixed plate 30 communicate with each other.
3), and when the movable rod 38a retreats, the rotary disk 34 rotates in the Y direction to connect each cylinder 35.
Fixed! ! 30 through-holes 33 communicate with each other (at this time, each passage 37 and each branch passage 32 of the passage 32 of the fixed platen 30
c).

Further, each cylinder 35 has a plunger 39.
is fitted so that it can reciprocate in its axial direction. 40 is a hydraulic cylinder (moving means), and a disc-shaped pressing member 4 is provided at the tip of a movable rod 41 of this hydraulic cylinder 40.
2 is fixed. A plurality of adjusting screws 43... are screwed into this pressing member 42, and each adjusting screw 43 is
The fixed platen 34 is provided at a position corresponding to each plunger 39 in the state shown in FIG. 2 (in which each passage 37 communicates with each branch passage 32c of the fixed plate 30).

50 is a mold consisting of a fixed mold 51 and a movable mold 52. The mold 50 is provided with the same number of cavities 53a, 53b, . These cavities 538, 53b... have different capacities. The fixed mold 51 has each cavity 5.
A plurality of sprues 5 each leading to 3a, 53b...
4a, 54b, . . . are formed. These sprues 54a, 54b, . . . are connected to each through hole 33 of the fixed platen 30, respectively.

By adjusting the protruding length from the end surface 42a of the pressing member 42, each of the adjusting screws 43 stops the movement of each plunger 39 when it moves toward the pressing member 42, and each cavity 53a, 53b... The amount of resin filled into each cylinder 35 is set according to the capacity of the cavity, and when the capacity of the cavity is small, the resin is made to protrude more from the end surface 42a.

Next, the operation of the injection molding machine configured as described above will be explained.

In a state where each passage 37 of the rotary plate 34 and each branch passage 32c of the passage 32 of the fixed plate 30 are in communication (in this state, each cylinder 35 and each corresponding through hole 33 are not communicated with each other), When the resin plasticized by the plasticizing device 20 is injected from the plasticizing device 20 into each cylinder 35 through the passage 32 of the fixed plate 30 and each passage 37 of the rotary plate 34 in the same manner as a conventional injection molding machine, As the resin flows into each cylinder 35, each plunger 39 moves backward toward each adjustment screw 43, comes into contact with each adjustment screw 43, and stops. At this time, the sealing member 36 is pressed against the bottom surface 31b of the recess 31 by the resin injection pressure and comes into close contact with the bottom surface 31b of the recess 31, thereby causing the above-mentioned clearance S from the tip opening of the injection hole 36a.
, to prevent resin leakage. Then, when all the plungers 39 come into contact with their corresponding adjustment screws 43, the supply of resin is stopped.

Next, the rotary disk 34 is rotated in the Y direction in FIG. 2 by the hydraulic cylinder 38, so that each cylinder 35 and each through hole 33 are communicated with each other. At this time, each passage 37 and each branch passage 32c become disconnected from each other, and the positions of each adjustment screw 43 and each plunger 39 are shifted.

Next, the movable rod 41 of the hydraulic cylinder 40 is extended by a predetermined length. Then, each plunger 39 is pushed forward by the end surface 42a of the pressing member 42, and each cylinder 3
Injection hole 36a formed in seal member 36 for the resin in 5
and is injected into each cavity 53a, 53b, . . . via the through hole 33 and sprue 54a, 54b. At this time, the sealing member 36 is pressed against the bottom surface 31b of the recess 31 by the resin injection pressure and comes into close contact with the bottom surface 31b of the recess 31, thereby preventing resin leakage from the tip opening of the injection hole 36a into the clearance S1. Further, due to the injection pressure, the rotary disk 34 moves in the direction opposite to the pushing direction of the plunger 39 by the clearance S, and comes into contact with the inner annular projection 31e.

Here, the amount of resin injected into each of the cavities 53a, 53b, . X) (area of the cylinder 35), by adjusting the protruding length of each adjustment screw 43 from the end surface 42a of the pressing member 42, it can be adjusted according to each of the cavities 53a, 53b... The injection amount can be measured.

Next, after retracting the movable rod 41 of the hydraulic cylinder 40, the rotary plate 34 is rotated in the X direction in FIG. communicate. After that, repeat the above operation.

In such an injection molding machine, the resin plasticized by the plasticizing device 20 can be measured in each cylinder 35 according to the capacity of each cavity 53a, 53b, and so on. The measured resin is transferred to hydraulic cylinder 4.
By setting 0, injection into each cavity 53a, 53b, . . . can be completed at the same time.

Therefore, good molding can be performed without the occurrence of flakes.

Also, when resin is injected into the cylinder 35, the seal member 3
6 is a recess 3 formed in the fixed plate 30 by resin injection pressure.
Since the injection hole 36 is pressed against the bottom surface 31b of the
It is possible to prevent resin leakage from the tip opening of a into the clearance Sl.

Furthermore, since the amount of resin injection is adjusted by adjusting the travel distance of each plunger 39 using each adjustment screw 43, there is an advantage that the amount of injection can be easily changed when the capacity of the cavity changes. .

In addition, in the above embodiment, each cylinder 35 has the same inner diameter, and the moving distance of each plunger 39 is adjusted by each adjustment screw 43 to measure the amount of injection into each cavity 53a, 153b, . The diameter (area) of the cylinder 35 and each plunger 39 is determined by each cavity 53a,
53b... may be changed depending on the capacity. In this case, since the moving distances of each plunger 39 can be made the same, each plunger 39 can be brought into direct contact with the end surface 42a of the pressing member 42 without providing each adjusting screw 43.

FIG. 5 shows a second embodiment of the present invention, and in this figure, the same elements as those shown in FIGS. 1 to 4 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, vacuum forming and injection molding are performed simultaneously.

In FIG. 5, reference numeral 60 denotes a mold consisting of a female mold 61 and a male mold 62. The female mold 61 has a plurality of through holes 63 for vacuum extraction, and each through hole 63 is connected to a vacuum pump or the like. Further, the female mold 61 is provided with cavities 64a, 64b, 64c, . . . having different capacities. 65 is a plastic sheet.

Next, the operation of the injection molding machine configured as described above will be explained. Note that the functions of the fixed plate 30, rotary plate 34, cylinder 35, plunger 39, seal member 36, etc. are the same as in the first embodiment, and will therefore be omitted.

The resin plasticized by the plasticizing device 20 is metered into each cylinder 35 in the same manner as in the device of the previous embodiment.

Next, the heated plastic sheet 65 is placed in the female mold 61.
and the male mold 62, and after lowering the female mold 61 or raising the male mold 62 and sandwiching them between them, the female mold 61 and the plastic sheet 65 are inserted through each through hole 63 using a vacuum pump or the like. The air between them is discharged and the plastic Notro 5 is placed in front of the female mold 61.

Next, the resin in each cylinder 35 is injected into each cavity 64a, 64b, 64c, . . . by the hydraulic cylinder 40. In this way, the plastic sheet 6
5 is still in the heated state, each cavity 53a, 5
The resin injected into 3b, 53c, . . . is completely welded to the plastic sheet 65.

In addition to the effects of the first embodiment, such an injection molding machine has the following effects.

In other words, vacuum forming is suitable for forming large, thin-walled products that are difficult to make with injection molding, but in principle, it is not possible to form products with a wall thickness greater than that of the sheet, so some parts of the molded product may have ribs, In the past, if a thick part such as a boss was desired to be provided, this could not be done at the time of molding, and the only solution was to mold it separately and then glue it in a separate process. For this reason, after molding, they were joined using an adhesive or welded, resulting in poor production efficiency. In the injection molding machine of this embodiment, ribs, bosses, etc. can be provided at the same time as vacuum forming, so production efficiency can be improved, and furthermore,
Even if the thick parts such as ribs and bosses have different sizes, they can be formed well.

Furthermore, since the bosses and ribs are formed while the plastic sheet 65 is heated, it is possible to obtain bosses and ribs that are stronger than those that are bonded together.

"Effects of the Invention" As explained above, according to the injection molding machine of the present invention,
When the plasticizing device and the measuring cylinders provided on the rotary disk are communicated and the resin plasticized by the plasticizing device is injected and fed into a plurality of measuring cylinders, the capacity of each measuring cylinder is The plunger in each metering cylinder moves until the capacity corresponds to the capacity of multiple cavities in the mold provided correspondingly to the cylinder, thereby metering the required amount of resin for each cavity. be able to. Then, the rotary disk is rotated to communicate each measuring cylinder with each cavity, and the moving means moves each of the plungers forward to pressurize the resin measured in the measuring cylinder. Injection of resin can be completed at the same time. Therefore, it is possible to perform good molding without overfilling a particular cavity with resin and causing cracks or the like.

Also, when resin is injected into the measuring cylinder, the sealing member 3
6 is pressed by the injection pressure of the resin and comes into close contact with the fixed plate, so that resin leakage from the sliding surfaces of the fixed plate and the rotary plate can be prevented. Therefore, the resin measured by the measuring cylinder can be injected into the cavity to achieve better molding, and it is also possible to prevent contamination of the molding machine, its installation environment, etc. due to resin leakage. .

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the injection molding machine of the present invention, FIG. 1 is a sectional view showing a schematic structure of the injection molding machine, and FIG. ■ Linear fixed view Figure 3 is a sectional view showing the measuring cylinder, Figure 4 is a sectional view of the main part showing the state in which the resin is pressurized by the plunger, and Figure 5 is the injection molding machine of the second embodiment. FIG. 6 is a cross-sectional view showing the schematic structure of a conventional injection molding machine. 20... Plasticizing device, 30... Fixed plate, 34... Rotating plate, 35... Cylinder (measuring cylinder), 36...
... Seal member, 39 ... Plunger, 40 ... Hydraulic cylinder (moving means), 50 ...
... Mold, 53 a, 53 b, 64 a, 64 b, 6
4 c--cavity. Figure 3

Claims (1)

[Scope of Claims] An injection molding machine in which resin is plasticized, measured and injected into a plurality of cavities in a mold, wherein a plasticizing device for plasticizing the resin and the mold are provided. A fixed plate is provided, a rotary plate is provided in the fixed plate so as to be rotatable about an axis, and a plurality of measuring cylinders extending parallel to the axis of the rotary plate and opening into the fixed plate are provided in the rotary plate. A plunger is provided in communication with the plasticizing device and each cavity, and a plunger is provided in each of the measuring cylinders so as to be able to reciprocate in the axial direction, and when the plunger is moved backward, the capacity of the measuring cylinder corresponds to the capacity of the cavity. A seal member is provided so as to stop at a position where the capacity is reached, and is pressed by the injection pressure of the resin to tightly contact the fixed plate to prevent resin leakage from the sliding surfaces of the fixed plate and the rotary plate, An injection molding machine further comprising a moving means for simultaneously moving each of the plungers forward.