JPH04144711A - Runner pellet-measuring and mixing feeder - Google Patents

Abstract

PURPOSE:To make the deviation of the mixing ratio between each shot as small s possible by a method in which the amount in which powered chip amount is subtracted from the resin amount corresponding to one molding shot is batch-wise measured synchronously with molding cycle and is discharged into a pneumatically transferring pipe path through a branched path. CONSTITUTION:The pneumatically transferring pipe path 4 for transferring powered chip which circulates the runner-powered chip discharged from the runner-crusher 2 fitted to a molding machine 1 and the new pellet-measuring device 10, 11 for virgin pellet connected mid-way of the pneumatically transferring pipe path 4 through a branched path, are provided. The new pellet- measuring devices 10, 11 measure the new pellet of the amount in which the amount of runner-powered chip is subtracted from the resin amount corresponding to one molding shot batch-wise synchronously with the molding cycle of a molding machine and discharge the pellet into the pneumatically transferring pipe path 4 through the branched path, and then mix the runner-powdered chip with each resin of one molding shot in transferring process.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to synthetic resin molding machines, especially injection molding machines, in which chips and fresh pellets obtained by crushing runners (in the case of colorless "Vourgin" Bere Soto alone, and (including when used in combination with master patch pellets colored with pigments in a desired color)) and supplies the molded product to the molding machine after injection. This invention relates to a device suitable for use in a molding device in which the runners separated and discharged from the runner are pulverized and recirculated as raw materials for subsequent molding shots.

<Prior Art> The crushing and recirculating use of a portion of a runner has been widely and commonly practiced, but for this purpose a special mixing device is required to mix fresh pellets of resin and crushed runner chips in a fixed ratio. was required in addition to a fresh pellet weigher.

Additionally, the addition of such a mixing device increases equipment costs and
Not only does this complicate the operation control of the entire equipment system, but since the crushed chips and fresh pellets are mixed in a relatively large volume for several shots, it is not always possible to guarantee ideal uniformity in the mixing ratio between shots. The reality is that some degree of variation in the mixing ratio is unavoidable.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to eliminate the need for any special mixing device and to minimize variations in the mixing ratio between crushed recirculated chips and fresh pellets between shots. The object of the present invention is to provide a runner/bellet quantitative mixing feeder that can be made small in size.

Means for Solving the Problems> In order to achieve the above object, the runner pellet quantitative mixing supply device of the present invention provides a runner pellet mixing supply device for transporting crushed chips that flows back from a runner crusher attached to a molding machine to a resin pumper of the molding machine. The apparatus includes an air transport pipe and a fresh pellet measuring device connected to an intermediate portion of the air transport pipe via a branch line, and the fresh pellet measuring device measures the amount of resin corresponding to one molding shot. The amount after subtracting the amount of crushed chips,
Weighing in batches in synchronization with the molding cycle of the molding machine,
It is characterized by a structure in which the air is discharged to the air transport pipe through the branch path.

The resin hopper is provided through the cylinder at the starting end side of the screw for melt extrusion,
A runner crusher is also commonly installed, and the air conveying pipe is installed in almost every molding device, at least from the fresh pellet weighing device to the hopper. be.

Therefore, in order to configure the metered mixing feeder of the present invention, it may be necessary to add an air conveying pipe section from the crusher to the fresh pellet metering device, but in most cases, the addition of special equipment for the pond is necessary. There's no need.

In the quantitative mixing supply device of the present invention, the fresh pellet measuring device measures the amount obtained by subtracting the amount of crushed chips from the amount of resin corresponding to one molding shot in a batch manner in synchronization with the molding cycle of the molding machine. However, it is particularly important that the air is discharged into the air transport pipe through the branch path.

It is desirable that the fresh pellets and the runner crushed chips are simultaneously pneumatically transported through the pipe.

Various types of fresh pellet weighing devices can be applied, but one example that is easy to control and has a simple structure is one in which a part of the cylinder is placed below the fresh pellet receiving hopper, and the upper part of the cylinder is connected to the weighing chamber. A shutter is interposed between the weighing chamber and the fresh pellet receiving hopper, and a piston with a variable upper limit height inside the weighing chamber is provided in the cylinder so as to be slidable up and down. Minimum upper piston height (not "discharge height")
A crushed chip discharging chute extending from a partial side wall of the cylinder to the air transport pipe may be provided below the cylinder.

Note that fresh pellet measuring devices are provided for the Vurgin pellets and the colored master patch pellets, respectively.

As described above, in the quantitative mixing supply device of the present invention, the runner crusher and the fresh pellet measuring device are operated in a batch manner in conjunction with the cycle of the injection molding machine, and the molded one-shot portion is transferred to the pneumatic transport pipe. Since the runner crushed chips and fresh pellets are reliably mixed in the conduit, they are fed into the resin hopper of the molding machine.

<Example> Hereinafter, an example of the quantitative mixing feeder of the present invention will be described with reference to the drawings. As shown in FIG. A pneumatic transport pipe (4) for transporting crushed chips is connected to the pipe (3).

In the molding machine (1), molten resin is injected at regular cycle time intervals from the resin melt mixed line area (5) containing a screw and cylinder into the mold storage area (6), so that the molded product and the runner are separated by a slight time difference. It is discharged with . A forward/reverse converter (8) is installed below the mold storage section (6) via a temporary storage hopper (), and when the molded product is ejected from the mold, the hopper (7) door (7a
) is open, the molded product is placed on the normally rotating conveyor (8) and discharged out of the molding machine in the direction of the arrow (Y) toward the front in the figure. As soon as the entire molded product has finished falling onto the conveyor (8), the door (7a) is closed, and then the runner is pushed out and discharged from the mold into the hopper (7). As soon as the molded product disappears from the conveyor, the conveyor (8) starts to reverse, and the door (7a) of the hombar is opened.
opens, the runner is transferred onto the conveyor, and the crusher (
2) as shown by the arrow (T).

The crushed runner shows the air transport pipe (4) as shown by the arrow (S).
As shown in Figures 1 and 2, the resin hopper (3) passes through the gas-solid separation cyclone (3a) in the upper part of the resin hopper (3) and is refluxed to the hopper. A main part (M) of the container is provided, and inside thereof, as shown in FIG. 2, fresh pellet weighing devices (10) and (11) are connected via a branch path (4a).

A fresh pellet receiving pot (10a) that receives Vurgin pellets and master patch pellets, respectively.
Below (11a) are part of the cylinder (10b),
(, 11b>), and the upper part of the cylinder is used as a weighing chamber (10c), (lie). A shutter (10
d) and (11d) are interposed, and the shutter is opened and closed in accordance with the injection cycle of the molding machine. Pistons (10e), (lle
), the upper limit height for metering inside the metering chamber is variable, and the height of the piston at the time of discharge is determined by the following payout chute (10f>,
(llf) (the upper limit height cannot be lower than the upper edge of the opening, i.e., this is the minimum value of the upper limit height). ).

Therefore, the piston is in the metering chamber (10c), (llc
), e.g. pneumatic cylinder <10i
) (lli>), and when the shutters (10cl) and (11d) are opened for a predetermined time, the bellet connects the shutters and the piston (11d).
0e) and (11e). Then,
The shutter (10d)
, (lid) is closed, and the piston is inserted into the dispensing chute (10f), (ll
pneumatic cylinder (10i), (1
1i>. As a result, the pellets of Vurgin and Masterbatch, which have fallen from the opening into the branching path (4a) via both chutes (1(H) and (llf)), merge in the branching path, and then are transported by air. The pellets are uniformly mixed with the chips flying through the conduit 4) and transported to the resin hopper (3).In this way, once the pellet measurement and discharge for one molded shot is completed, The piston is returned to the upper limit height again and is ready for the next cycle.

In addition, a rectifying shutter (4b) base is fixed to the starting end of the confluence of the branch path (4a) and the air transport pipe (4), and the shutter gradually becomes lower from the upstream side to the downstream side of the air flow. It is installed in an oblique position from the upper end of the pipe inner wall to the center of the pipe cross section.

This shutter (4b) prevents pellets from falling instantaneously and in large quantities to the confluence point and blocking the pipe (4), and is one of the important components in the device of the present invention. It is.

Moreover, the bars (10h), (llh) fixed to the piston rod between the pistons (10e), (lie) and the pneumatic cylinders (10i), (lli>) are vertical threaded rods (10g) whose vertical positions are variable. , (l1g), the upward movement of the piston is stopped and the piston is maintained at the upper limit height.On the other hand, when the piston rod is moved downward after weighing the pellet, the above-mentioned bar The piston is maintained at the above-mentioned discharge height by the impact of the base against the fixed upper end frame member of the pneumatic cylinder (10i), (lli).

As described above, the fresh pellet weighing device (10),
(11) is 70% of the remaining amount after subtracting the amount of crushed chips, for example 30%, from the amount of resin corresponding to one molding shot.
is metered batchwise in synchronization with the molding cycle of the molding machine, and is then fed to the air transport pipe (4) through the branch pipe (4&).
The fresh pellets are uniformly mixed with the runner-pulverized pellets in the conduit.

By the way, for stable operation of the injection molding machine, it is necessary to supply the resin hopper (3) with a slightly larger amount of the chip/bellet mixture than the average amount of resin required for injection molding, for example, 2 to 3% more. . Therefore, if the operation of the injection molding machine is normal and the resin supply continues to be good, the resin hopper (
3) The amount of resin inside increases little by little until it exceeds the upper limit level in the hopper. Therefore, in response to the "level over" alarm signal and control signal transmitted from the level sensor, the hopper (1
A branch shutter (13) for switching the mixed resin conveyance toward 2a) is provided on the downstream side of the branch path (4a). The shutter (13) and the hopper (12&
) is connected with another branch road (14).

For one embodiment of the invention described above, for example, the fresh pellet metering device <11 for colored pellets (masterbatch>) may be omitted, or multiple masterbatch metering devices may be used to provide a complex intermediate color to the molded product. Modifications can be made, such as equipping the piston with a device and adopting other conventionally known systems such as an electromagnetic type as a mechanism for controlling the upper and lower height limits of the piston.

<Effects of the Invention> As described above, according to the present invention, there is no need for a special mixing device, which has conventionally been essential in resin molding equipment that crushes runners and recirculates them as molding raw materials, resulting in lower equipment costs. In addition, since the mixing for each shot of molding is performed automatically, variations in the mixing ratio between shots are extremely reduced, which greatly contributes to improving the quality of molded products.

[Brief explanation of the drawing]

FIG. 1 is an overall explanatory diagram schematically showing an embodiment of the present invention, and FIG. 2 is an enlarged front view of the main parts. In the figure, (1) is a molding machine, (2) is a runner crusher, and (3) is a runner crusher.
is a resin hopper, (4) is an air transport pipe, (4a) is a branch line, (10), m> is a fresh pellet weighing device.

Claims (1)

[Claims] 1. Pneumatic transport for transporting pulverized chips that returns runner pulverized chips from a runner pulverizer (2) attached to the molding machine (1) to the resin hopper (3) of the molding machine (1). A pipe line (4), and fresh pellet measuring devices (10) and (11) for at least virgin pellets connected to an intermediate portion of the air transport pipe line (4) via a branch line (4a). The fresh pellet weighing device (10), (1
Fresh pellets in an amount obtained by subtracting the amount of the runner crushed chips from the amount of resin corresponding to one molding shot in step 1) are weighed in batches in synchronization with the molding cycle of the molding machine (1), and are transferred to the branch path ( 4a) to the air transport pipe (4), and is configured to mix with the runner crushed chips one molded shot at a time during conveyance.