JP3018307B2 - Material change and color change method and apparatus in injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding machine in which a material change or color change (hereinafter, material change, color change) of a molding material in a heating cylinder head or an injection cylinder is performed in an in-line screw type injection molding machine. Material change in the machine,
The present invention relates to a color change method, a material change, and a color change device.

[0002]

2. Description of the Related Art Inline screw type injection molding machines of this type have conventionally been known to have various structures, and are effective in mass-producing and molding plastic products having a required shape from plastic materials. It can be demonstrated. By the way, in such an injection molding machine, molding is often performed by changing a plastic material, and molding is often performed by changing the color of the same type of plastic material in the same mold. ing.

Conventionally, the following method has been generally used for changing the material and color of a plastic material as a molding material in this type of injection molding machine. That is, FIG. 5 shows the details of the nozzle portion 2 on the distal end side of the injection cylinder 1 in the injection molding machine, and the molding material injected from the nozzle portion 2 passes through the inlet of a molding die (not shown). A molding material that has been melted into the cavity is injected.

[0004] Reference numeral 3 denotes a screw having a spiral groove provided in the cylinder 1 so as to rotate and advance and retreat. The screw 3 retreats from the nozzle portion 2 while rotating, so that the outer end side of the cylinder 1 is provided. The molding material in a hopper (not shown) provided in the apparatus is gradually fed.

A heating means for the molding material is provided at an appropriate position on the outer periphery of the cylinder 1 so that the molding material from a hopper provided on the outer end side of the cylinder 1 is used for the rotation and retreat operation of the screw 3. During the supply, the resin is sequentially heated and melted, and is injected and supplied from the nozzle portion 2 into the cavity of the molding die. The configuration and the like are well known, and detailed description thereof will be omitted. Omitted.

In the conventional injection cylinder 1 as described above, in order to change the material and color of the molding material, the original molding material is supplied to a hopper which is a supply unit on the outer end side of the injection cylinder 1. The supply of the (old material) 4 is stopped, and then the supply and supply of a new molding material (new material) 5 are started. And weighing,
By repeating injection several times, the original molding material 4 is gradually extruded from the nozzle portion 2 to be removed, and a new molding material 5 is removed.
This was done by replacing

There is also known an injection cylinder 1 having a structure in which an open / close valve 7 as shown in FIG.

Material change and color change in the injection cylinder 1 having such a structure have been performed as shown in FIGS. 6 (a), 6 (b) and 6 (c). That is, while gradually adding new molding material from a hopper (not shown) on the rear end side of the injection cylinder 1, as shown in FIG.
The valve 7 at the front end is closed, and the screw 3 is rotated and moved backward to concentrate the original material 4 at the front end of the cylinder. Next, as shown in FIG. 2B, the valve 7 is opened and the screw 3 is advanced, and the material 4 at the tip of the cylinder 1 is pushed out from the nozzle portion 2 and injected.

The measurement step (a) and the injection step (b) are repeated a plurality of times according to the opening / closing operation of the valve 7 as is apparent from FIG. Material 4 was gradually extruded and removed, and the inside of the cylinder 1 was replaced with a new molding material.

[0010]

However, in the above-described material change and color change in the conventional injection molding, the original molding material 4 is gradually replaced with a new molding material by repeating the measurement of the injection cylinder 1 and the injection operation. In this replacement operation, a molded product in which old and new materials are mixed is obtained, and not only waste is caused in the molding material, but also such a replacement operation takes a long time. There was a defect.

Further, in such a conventional material changing and color changing method, it is practically impossible to completely remove the original molding material that stays and adheres to the inner wall portion of the nozzle portion 2 of the injection cylinder 1. It was near possible and lacked certainty.
Further, there is also a quality problem that a molded product defect occurs in which the original molding material fixed as described above is peeled off and injected for a long period of time, and material replacement and color replacement can be performed effectively and efficiently. However, it is desired to take some measures that can eliminate these problems.

[0012] That is, the material change and color change in the injection molding described above are quite troublesome and require complicated operations and operations, and are extremely troublesome. However, they are important in maintaining the molding accuracy of the molded product. This is one of the issues to be addressed. In particular, the injection cylinder 1 having the heating means, the nozzle part 2, the valve 7,
Furthermore, if the original molding material adhering to the screw 3 or the like is properly replaced with a new molding material, and it is not quickly and completely replaced, it is not merely a matter of material change, labor at the time of color change, waste of time and material. Will be.

[0013] If such material change or color change is insufficient and the original molding material remains, only a few shots to several tens of shots are applied to the surface of the molded article during continuous molding. Even if it is slight, the original material before replacement is mixed and injected, which causes a problem such as a defective molded product. Further, when such a problem occurs, there is a possibility that a production plan will be confused and a delivery date will be delayed, which may cause a serious problem. Therefore, it is desired to take some measures which can eliminate these problems.

In particular, such a problem is extremely important in quality control because, in a factory which is almost unmanned using an automatic product take-out device, a conveyer for molded products, an automatic product stocking device, etc., its discovery is delayed and quality control is important. Problem.

Further, such a material change and color change operation has conventionally been performed depending on the skill of a skilled worker or an instructor in a molding factory. Variations are inevitable, materials and time cannot be wiped out, and it cannot be said that uniform and reproducible material change and color change work can be performed. is needed.

For this reason, the applicant of the present invention has disclosed Japanese Patent Publication No. 57-26.
Japanese Patent Publication No. 215 proposes a technique in which material change and color change are performed by a method considered to be the most effective method. In other words, by skillfully adjusting and controlling the movement of the screw such as rotation, forward speed, reverse speed and the injection operation, material change and color change are performed as efficiently as possible, and the original material fixed inside the cylinder etc. Materials are to be eliminated as much as possible.

However, according to such a method, the molding material such as the original plastic material sticks to the inside of the tip of the cylinder, and the material and color changes with high reliability can be quickly and minimized. It cannot be said that it can be done, and it is necessary to consider these points and solve the above-mentioned problems.

The present invention has been made in view of such circumstances, and material change and color change in an injection cylinder can be performed efficiently and in a short time by a very simple and simple operation. It is an object of the present invention to provide a method and an apparatus for material change and color change in an injection molding machine capable of reliably removing even sticking.

[0019]

In order to meet such a demand, a method of material change and color change in an injection molding machine according to the present invention is described in an injection cylinder of an in-line screw type injection molding machine. After alternately repeating the operation of retracting the screw while rotating the screw with the valve closed and the operation of moving the screw forward with the valve open, the valve is opened and the screw retracted. The operation of moving the screw forward with the valve closed and then opening the valve in the middle thereof is alternately repeated several times to change the material and color in the injection cylinder.

Further, replacement material in an injection molding machine according to the present invention, color change device is carrying out the material exchange or color change in the injection cylinder in-line screw type injection molding machine, the injection cylinder tip portion of the valve of the valve A first sequence device that alternately repeats several times a screw rotation and retreat operation in a closed state and a screw advance operation in a valve open state of the valve, and a valve in a valve open state following the sequence operation. A second sequence device is provided which alternately repeats a screw retreating operation, a screw advancing operation in a valve closed state of a valve, and a valve opening state operation during the screw advancing operation several times.

[0021]

According to the present invention, when performing material change or color change in the injection cylinder of the in-line screw type injection molding machine, the first sequence device first closes the valve at the tip of the cylinder, and the screw is closed. Is rotated backward to supply the molding material to the screw tip inside the cylinder tip, and the second sequencer opens the valve to advance the screw and eject the supplied material from the cylinder tip. The operation is repeated several times, and the valve is continuously opened, the screw is moved backward, air is sucked in, and the screw is moved forward with the valve closed. The operation of opening the valve and discharging the material at the tip of the cylinder while compressing it with air is repeated several times. Than it is.

[0022]

1 to 3 show one embodiment of a material change, color change method and apparatus in an injection molding machine according to the present invention. In these figures, the same figures as those in FIGS. 5 and 6 described above are used. Or, corresponding parts are denoted by the same reference numerals, and detailed description is omitted.

According to the present invention, as a material change and color change method in an injection molding machine, as is apparent from FIG.
In the injection cylinder 1 of the in-line screw type injection molding machine, an opening and closing valve 7 such as a shut-off valve at the tip of the nozzle portion 2 of the cylinder 1 is closed, and the operation of retracting the screw 3 while rotating the screw 3 is performed. The operation of moving the screw 3 forward with the valve open is repeated several times alternately, and then the operation of retracting the screw 3 with the valve 7 in the open state and the operation of moving the screw 3 forward with the valve 7 in the valve-closed state are performed. The operation of setting the valve 7 to the valve open state is repeated several times alternately, so that the material change and the color change in the injection cylinder 1 are performed.

Here, the respective processing steps described above are shown in FIGS. 1 (a), 1 (b), 1 (c) and 1 (d).
Is a measuring step substantially similar to the conventional one, and (b) is an injection step. Further, in the figure, (c) and (d) are steps newly added according to the present invention, (c) is a retreating step of the screw 3 with the valve open, and (d) is an open state halfway from the valve closed state. This is a forward step of the screw 3 for switching to.

By adopting such a configuration, in addition to the conventional metering and injection steps, a screw retreating step for introducing air into the cylinder 1 and the suction air and the molding materials 4 and 5 are compressed. , By combining the screw advance step that discharges on the way,
The original material 4 can be efficiently and reliably removed. In particular, it is part A that the original material 4 stays and adheres for a long time in the injection cylinder 1, and it is necessary to efficiently and surely remove the material in this part. The elimination of the material 4 in the part A is performed by suction air and its compression.

That is, according to the present invention, FIG.
By performing the operations (c) and (d) in the above, the inner wall portion (A
First, in order to melt the original material 4 attached to the portion (4) and remove it efficiently and reliably and to remove it, first, FIG.
By performing the above steps, the distal end of the cylinder 1 is brought to a state close to the negative pressure, and the original material 4 that has adhered and stuck is easily peeled off.

Next, the valve 7 is opened in the step of FIG. 3B, and the original material 4 and the new material 5 are sequentially discharged and removed, and as shown in FIG. Is sucked into the inside from the nozzle portion 2 and then, in the step shown in FIG. 3D, the air and the molding material inside the cylinder 1 are sequentially compressed, and when a predetermined pressure is reached, the valve 7 is opened to perform rapid exhaust. Is repeated a plurality of times as shown in (e) of the figure, so that unnecessary materials and time are reduced, and material change and color change can be performed efficiently and quickly.

When the screw 3 is advanced with the valve 7 in the closed state as shown in FIG. 2A in the step (d) of FIG. 1 described above, as shown in FIG. The compressed air is compressed at the distal end of the cylinder 1, and the compressed air stays on the inner wall of the distal end of the cylinder 1, as shown in FIG. In addition, the surface temperature is lowered by cooling with suction air, and the viscosity is increased. As a result, when the valve 7 is opened as the screw 3 moves forward, it is scraped off by the compressed air, and the adhered material 4 is peeled off. And can be discharged properly and reliably.

In FIGS. 2A and 2B, reference numeral 9 denotes a sealing spacer provided on the screw 3 for forming a compressible space at the tip of the cylinder 1.

Here, if such a material change and color change method is adopted, as is apparent from before and after the improvement in FIG. The amount of material used (package amount) is 11.5 kg /
It has been confirmed by experiments that the amount can be reduced by about 43% from 6.5 times to 6.5 kg / time. This experiment shows an example in which the same material such as a polypropylene composite material and the like is changed from a cool gray color to a warm gray color. Also, when the color is changed from black to warm gray with another polypropylene composite material, the package amount per color change is from 22 kg to 10.7 kg,
The reduction was about 51%.

Further, the material changing and color changing devices in the above-described injection molding machine according to the present invention include a valve 7 at the tip of the injection cylinder 1 of the in-line screw type injection molding machine.
A first sequence device (not shown) that alternately repeats the screw 3 rotation and retreat operation in the valve closed state and the screw 3 advance operation in the valve open state of the valve 7 several times. Subsequently, the screw 3 retreating operation with the valve 7 opened, the screw 3 advancing operation with the valve 7 closed, and the valve opening operation during the screw 3 advancing operation are alternately repeated several times. Preferably, a second sequence device (not shown) is provided.

According to the above method and configuration,
In the injection cylinder 1 of the in-line screw type injection molding machine, the first sequencer first closes the valve 7 at the tip of the cylinder 1 and retreats the screw 3 while rotating the screw 3 to transfer the molding material 5 to the cylinder 1. The operation of supplying the material to the screw 3 tip side inside the tip portion and opening the valve 7 to advance the screw 3 and ejecting the supplied material from the tip portion of the cylinder 1 is repeated several times by the second sequencer. Subsequently, the valve 7 is opened and the screw 3 is moved backward to suck air, and then the screw 3 is moved forward while the valve 7 is closed. Is repeated several times to open the valve and discharge the molding material 4 stuck to the tip of the cylinder 1 while compressing it with air. The Ukoto, would perform the material exchange or color change in the injection cylinder 1.

The present invention is not limited to the structure of the embodiment described above, and it goes without saying that the shape, structure and the like of each part of the injection cylinder 1 can be appropriately modified and changed. For example, in the above-described embodiment, the case where the present invention is applied to the injection cylinder 1 of the in-line screw type injection molding machine has been described, but an appropriate modification may be considered. Further, in the above-described embodiment, the material change and the color change are performed by repeating a plurality of times.
Needless to say, it can be set and changed as needed.

[0034]

As described above, according to the material change and color change method in the injection molding machine according to the present invention, the valve at the tip of the injection cylinder is closed, the screw is rotated, and the valve is retracted while rotating. The operation of moving the screw forward with the valve opened is repeated several times, then the operation of retracting the screw with the valve open and the screw moving forward with the valve closed and opening the valve in the middle. The operation of opening is repeated several times alternately, and the material change and color change in the injection cylinder are performed. Therefore, although it is a simple method, it adheres particularly to the tip inner wall portion in the injection cylinder. It is possible to eliminate quickly, reliably and efficiently, including the original molding material, so that material change and color change in the injection molding machine can be performed by using the minimum necessary waste material. Easy, exhibits various excellent effects such as attained shorten the time required during reduction and switching of material costs.

Further, according to the material changing and color changing apparatus in the injection molding machine according to the present invention, the screw rotation and the retreating operation of the valve at the end of the injection cylinder with the valve closed , and the screw advance with the valve open. A first sequence device that alternately repeats the operation several times, a screw retreating operation with the valve opened, a screw advancing operation with the valve closed, and the screw advancing operation following the sequence operation A second sequence device that alternately repeats the valve opening state operation in the middle and several times is used, and material change and color change in the injection cylinder of the in-line screw type injection molding machine are performed. , The original molding material adhering to the inner wall of the tip of the injection cylinder can be quickly and reliably peeled off, and can be efficiently removed. Easy by the material used, Hakare to shorten the necessary time for reduction and switching of material costs, yet exhibits an excellent effect of equal device structure is simple.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a method and an apparatus for material change and color change in an injection molding machine according to the present invention.
(B), (c), and (d) are diagrams showing operation steps at the time of material change and color change, and (e) is a diagram showing a repetitive operation state thereof.

FIGS. 2A and 2B are enlarged views of a main part shown in FIGS. 1A and 1B for explaining the operation and effect of the operation steps in FIG. 1D, which characterize the present invention.

FIG. 3 is an enlarged view showing the operation and effect of FIG. 2 (b).

FIG. 4 is a graph for explaining the function and effect of the present invention in comparison with a conventional example.

FIG. 5 is a schematic diagram showing a schematic configuration of a conventional injection cylinder.

FIGS. 6A and 6B are diagrams for explaining material change and color change in a conventional injection cylinder, in which FIGS. 6A and 6B show operation steps, and FIG. 6C shows a repetitive operation state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection cylinder 2 Nozzle part 3 Screw 4 Original molding material 5 New molding material 7 Open / close valve

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masao Nakano 100 Kanayama, Ichiriyama-cho, Kariya City, Aichi Prefecture Inside Toyota Auto Body Co., Ltd. Ube Machine Co., Ltd. (56) References JP-A-61-293823 (JP, A) JP-A-62-77913 (JP, A) JP-A-63-30221 (JP, A) JP-A-63-297012 (JP, A) JP-A-2-252517 (JP, A) JP-A-3-114813 (JP, A) JP-A-4-82720 (JP, A) JP-A-5-124079 (JP, A) JP-A-6-320589 (JP, A) JP-A-7-24877 (JP, A) JP-A-6-293046 (JP, A) JP-A-3-64721 (JP, U) JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00 -45/24

Claims (2)

(57) [Claims] 1. An inline screw type injection molding machine, comprising: a method of changing the material of a molding material and a method of changing colors in an injection cylinder in an injection cylinder. After alternately repeating the operation of retracting the screw while rotating the screw in the closed state and the operation of moving the screw forward with the valve opened, the operation of retracting the screw with the valve open and the valve A method of changing materials and changing colors in an injection molding machine, which alternately repeats the operation of moving the screw forward with the valve closed and opening the valve in the middle thereof several times. 2. An inline screw type injection molding machine, comprising: a material changer and a color changer for performing a material change and a color change of a molding material in an injection cylinder, wherein a valve provided at a tip portion of the injection cylinder is provided. A first sequence device for alternately repeating a screw rotation and retreat operation and a screw advancing operation of the valve in the valve open state several times while the valve is in a closed state, and an operation by the first sequence device. Subsequently, a second sequence in which the screw retreating operation in the valve open state of the valve, the screw forward operation in the valve closed state, and the valve opening operation in the middle of the screw forward operation are alternately repeated several times. A material changer and a color changer in an injection molding machine, comprising: