JPH06328497A - Method and apparatus for manufacturing molded product - Google Patents

Abstract

PURPOSE:To provide a manufacturing method and apparatus capable of enhancing the productivity even in the case where the mold is constituted as a single cavity mold. CONSTITUTION:A plurality of mold clamping units 14 are provided on a table 10, and while a dwelling device 16 for keeping molding material injected into the cavity of a mold is provided relative to respective mold units 14, the extrusion mechanism 54 of an injection device for injecting molding material within the chamber into the cavity by pushing out the plunger is provided in a state of separation from the mold clamping units 14 and dwelling device 16. After the molding material is put into an action for injection by an injection device comprising the extrusion mechanism 54 and plunger, the molding material is rotationally moved by the table 10 together with respective mold clamping units 14 and dwelling device 16 in a dwelling condition, and the molding material within the cavity is cured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing apparatus and a manufacturing method suitable for manufacturing a precision molded product of a thermosetting resin.

[0002]

2. Description of the Related Art As a method of manufacturing a resin molded product, there are a method of manufacturing a molding material by injection molding, a method of manufacturing a transfer molding and the like. Of the resin molded products,
In the case of thermoplastic resin molded products, the manufacturing method by injection molding is often used, but in the case of thermosetting resin molded products, the curing reaction of the molding material ends even after the molding material is injected into the mold cavity. Since the molding material must be kept in a pressurized state until the above, manufacturing by injection molding is difficult. Therefore, a manufacturing method by transfer molding is generally adopted.

FIG. 7 shows an example of a conventional manufacturing apparatus by transfer molding. The manufacturing apparatus shown in the figure includes a mold clamping cylinder 100 and a fixed platen 10.
2. A mold material injection device 112 is fixedly provided in a mold clamping unit 110 including a movable plate 104, a tie rod 106, a heating plate 107, a holder 108 and the like.

This manufacturing apparatus has an injection cylinder 118 with a molding material 116 set in a chamber 114.
When the plunger 120 is extruded by the above method, the heated molding material 116 is injected into the cavity 124 of the molding die 122 and solidified.

When the molding material 116 is a material such as a thermoplastic resin which reacts quickly, the molding material 116 is rapidly solidified at the gate portion having a narrow passage cross-sectional area after the molding material 116 is injected into the cavity 124. Since the backflow of the molding material 116 from the cavity 124 is prevented and the molding material 116 is quickly solidified also in the runner portion and the sprue portion, a short time (for example, 1 second to 10 seconds) after the molding material is injected.
It is possible to perform molding without any trouble even if the plunger 120 is retracted after the elapse of seconds. Also, after molding,
Since the molding material 116 is solidified in the runner portion and the sprue portion, this (burr) can be easily removed from the molding die 122.

In the case of a thermosetting resin, however, it is necessary to hold the injected molding material 116 in a pressurized state until it is solidified in the cavity 124. It is necessary to keep the plunger 120, which has extruded the molding material 116 in the chamber 114, as it is and continue to apply pressure to the molding material of the cavity 124 and the runner portion.

By the way, in the case of the conventional single-acting type manufacturing apparatus, it is unavoidable that a series of molding cycle times from the mold clamping to the injection of the molding material, the solidification, the mold opening, and the removal of the molded product become long.

In this case, in order to improve the production efficiency, a large number of normal forming dies 122 are taken. However, in the case of a precision molded product that requires strict dimensional accuracy of the molded product, it may be difficult to obtain multiple molding dies 122 per se.

Although a method such as electric discharge machining is used as a method of manufacturing a molding die (die), it is not possible to precisely machine the molding die with dimensional accuracy of, for example, 1 micron order by electric discharge machining. When such a high dimensional accuracy is required, the dimensional accuracy is obtained by polishing, but in order to perform the polishing precisely, the molding die must be divided into a plurality of small blocks. If the forming die is divided into blocks in this way, it becomes difficult to obtain a large number of them.

That is, in the case of the conventional manufacturing apparatus, in order to manufacture a molded article with a high precision of a certain level or more, it is necessary to perform the molding operation one by one, which makes it difficult to increase the production efficiency.

[0011]

The invention of the present application has been made to solve such a problem. Thus, the first invention of the present application is a chamber for accommodating a molding material, a plunger for extruding the molding material set in the chamber and injecting it into a cavity of a molding die, and a mold for clamping the molding die. In an apparatus for manufacturing a molded product including a clamping unit, an extrusion mechanism that applies a predetermined pressing force to the plunger to inject the molding material in the chamber into the cavity by the plunger is separated from the plunger and the mold clamping unit. And the injection mechanism and the plunger constitute an injection device for the molding material, while the extrusion mechanism includes a pressurization mechanism for holding the extrusion-operated plunger at the extrusion position with a predetermined pressing force. And the pressure clamping mechanism and the plunger form a pressure maintaining device. 1).

Another invention of the present application relates to a method for manufacturing a molded article, including a chamber for containing a molding material, a plunger for extruding the molding material set in the chamber and injecting it into a cavity of a molding die, In an apparatus for manufacturing a molded product, which includes a mold clamping unit for clamping the mold, an extrusion mechanism that applies a predetermined pressing force to the plunger to inject the molding material in the chamber into the cavity by the plunger is used. The plunger and the mold clamping unit are disposed separately from each other, and the extrusion mechanism and the plunger constitute an injection device for the molding material, while the plunger that has been extruded is held at the extrusion position with a predetermined pressure. The pressurizing mechanism is provided separately from the extruding mechanism and is fixedly provided to the mold clamping unit, and the pressure maintaining device is provided by the pressurizing mechanism and the plunger. And injecting the molding material into the cavity of the molding die by the pouring device at a predetermined pouring station, and then molding the molding material in the cavity while maintaining the pressurizing state of the molding material in the cavity. The mold, the mold clamping unit, and the pressure holding device are all moved to a molded product take-out station, and the molding material is solidified in the cavity during the moving time (claim 2).

[0013]

According to the apparatus of the first aspect of the present invention, while the molding material injected into the cavity of the molding die at a predetermined pressure is kept under pressure by the pressure holding device,
It is possible to move the mold clamping unit and the pressure holding device separately from the extrusion mechanism of the injection device.

Therefore, the molding material is successively poured into new molding dies at the same pouring station, and the molding dies after the pouring are moved to the molding product take-out station in the mold clamping state, during which the molding material is fed. It can be solidified in the mold cavity.

According to a second aspect of the present invention, the molding die is moved together with the pressure holding device in the mold clamping state by the mold clamping unit, and after the molding material is injected into the cavity of the molding die by the pouring device at the pouring station. By moving these to a take-out station under a pressure-holding condition by a pressure-holding device and solidifying the molding material in the meantime, according to the present invention, continuous production of molded products becomes possible, and a single-piece molding die Even when using, the production efficiency can be effectively increased.

[0016]

EXAMPLE An example in which the present invention is applied to the manufacture of a small precision molded product of a thermosetting resin (a precision molded product required to have a dimensional accuracy of 1 micron order) will be described in detail with reference to the drawings. .

In FIG. 1, reference numeral 10 denotes a circular table which is rotationally driven by a drive shaft 12, in which mold clamping units 14 are fixedly installed at six positions in the circumferential direction, and a pressure holding device 16 is fixed to the mold clamping unit 14. Is provided for the purpose.

FIG. 3 is an enlarged view showing a specific structure of the mold clamping unit 14. As shown in the figure, the mold clamping unit 14 includes a fixed plate 18, a movable plate 20, a tie rod 22,
It has a mold clamping cylinder 24. The movable platen 20 has a heating plate 2
6 is fixed upward, and the fixed platen 18 is provided with a heating platen 28 via a holder 30 facing downward.

The heating plate 28 on the stationary platen 18 side is provided with a chamber 32 for accommodating the molding material (thermosetting resin in this example), and the holder 30 holds the molding material in the lateral direction. An insertion space 34 for inserting and setting in the chamber 32 is formed.

Reference numeral 36 is a molding die, 38 is a conveying guide for inserting and setting the molding die 36 between the pair of heating plates 26, and 40 is a guide roller.

The molding die 36 is constructed as a single piece, and its cavity is machined with high dimensional accuracy on the order of microns. The molding die 36 is in a mold-clamping state at the stations shown in FIG. 2 described below, that is, at stations other than the station for disassembling the die and taking out the molded article and the die exchange station.

Here, the station is a station for injecting the molding material into the cavity of the molding die 36,
At the stations, a curing reaction (crosslinking reaction) is performed while the molding material is maintained in a pressure-holding state.

On the upper surface of the stationary platen 18 of the mold clamping unit 14, an air cylinder 42 is fixedly installed upward as shown in FIG. The rod of the air cylinder 42 is connected to the plunger 46 via the connecting member 44.

Here, the plunger 46 pushes out the molding material set in the chamber 32 to form the molding die 3.
6 is injected into the cavity. In this example, the air cylinder 42, the plunger 46, and the connecting member 44 form the pressure maintaining device 16.

Incidentally, as shown in FIG.
A fitting portion 48 is formed on the guide rod 50. The fitting portion 48 is slidably fitted to the guide rod 50, and the connecting member 44 is moved up and down under the guide of the guide rod 50. ing.

The upper surface of the connecting member 44 is a horizontal and flat pressed surface 52 to which a pressing force of a hydraulic cylinder 56 (see FIG. 1) described later is applied.

In FIG. 5, reference numeral 54 is an extrusion mechanism for pressing the plunger 46 in the station of FIG. 2 to extrude the molding material in the chamber 32, and the hydraulic cylinder 5
6 is included as a main element.

The hydraulic cylinder 56 is fixed above the mold clamping unit 14 to the frame 60 via a mounting member 58, and a plate 62 is fixed to the tip of the downward rod.

The plate 62 has a pair of guide rods 64.
Are fixed, and these guide rods 64 are slidably fitted to a guide cylinder 66 provided on the attachment member 58. Thus, the plate 62 has these guide rods 6
4. It is moved up and down under the guide of the guide cylinder 66.

On the lower surface of the plate 62, a pressing head 68 for applying a pressing force to the plunger 46, strictly speaking, to the pressed surface 52 of the connecting member 44 is provided downward.

Here, the hydraulic cylinder 56 has a larger thrust (driving force) than the air cylinder 42 in the pressure-holding device 16. In this example, the pushing mechanism 54 including the hydraulic cylinder 56 and the plunger 46 are connected to each other. Due to
An injection device for injecting the molding material into the molding die 36 is configured.

Next, the operation of the apparatus of this example will be described with reference to FIG. In the apparatus of this example, the molding material is injected into the cavity of the molding die 36 at the station shown in FIG. The specific operation is as follows. That is, at this station, as shown in FIG. 1, the auto hand 70 first grabs the molding material (tablet) and inserts it laterally into the insertion space 34 of the holder 30.
Set in chamber 32. At this time, the mold clamping unit 14 is in a state where the molding die 36 is clamped (FIG. 6A).
reference).

When the setting operation of the molding material is completed, the hydraulic cylinder 56 of the extrusion mechanism 54 arranged above the mold clamping unit 14 at the station is operated to move the plate 62 downward (FIG. 6 (B)). )reference). Then, the plunger 46 is pushed downward through the connecting member 44, and the molding material set in the chamber 32 is pushed out from the chamber 32 and injected into the cavity of the molding die 36.

The hydraulic cylinder 56 that pushed out the plunger 46 keeps it in a pressed state for a certain time (for example, several tens of seconds), and then pulls in the rod to separate the pressing head 68 from the connecting member 44 upward.

On the other hand, the air cylinder 42 of the pressure maintaining device 16 is
Even after the hydraulic cylinder 56 releases the pressing force on the plunger 46, the connecting member 44 is connected to the plunger 46.
Continue to apply pressure through. That is, pressure is continuously applied to the molding material injected into the cavity (Fig. 6 (C)).
reference).

A strong force is required to inject the molding material in the chamber 32 into the cavity. The hydraulic cylinder 56 pushes and advances the plunger 46 downward with a strong force necessary for that purpose. However, the subsequent holding step does not require much force. In this device,
The air cylinder 42 continues to pressurize the plunger 46 with a pressing force smaller than the pressing force of the hydraulic cylinder 56.

The molding material injected into the cavity of the molding die 36 is intermittently sent to the next station under the pressure-holding condition of the pressure-holding device 16, and at the station, the molding die 36 is pressed. The mold is opened, and the molded product solidified in the cavity is removed from the molding die 36 while moving the stations.

Subsequently, the molding die 36 is cleaned and assembled in this station, and then sent to the station again through the station, where the molding die 36 is molded into the cavity under the mold clamping state again. Material injection is performed.

As described above, according to this embodiment, after the molding material is injected into the cavity of the molding die 36 at the station, the molding die 36 and the mold clamping unit 14 are held under a pressure-holding condition.
Can be moved together.

On the other hand, in the station, the molding material can be successively poured into the molding die 36 newly sent. As a result, it becomes possible to continuously manufacture molded products, and the production efficiency can be effectively increased even when the molding die 36 is formed as a single piece.

In this example, the continuous production of the molded product is possible because the pressure-holding device 16 is separated from the injection device, more specifically, the extrusion mechanism thereof, and the mold clamping units 14 are integrally moved. This is due to the provision.

It is conceivable, however, that each of the mold clamping units 14 is provided with the pushing mechanism 54 including the above-mentioned hydraulic cylinder 56, and these are moved together with the mold clamping units 14.

However, in this case, it is necessary to provide a large-scale device such as a hydraulic circuit and a rotary joint mechanism for continuously supplying the hydraulic pressure to the rotating hydraulic cylinder 56, and the manufacturing apparatus becomes large as a whole. Equipment costs are high. There is also a problem of oil leakage in the rotary joint mechanism.

However, when the extruding mechanism for injecting the molding material and the pressure-holding device are separated, it is possible to set the pressure of the pressure-applying mechanism in the pressure-holding device to a small value. The cylinder 42 can be adopted. In this case, a simple air circuit or the like for supplying air pressure to the air cylinder 42 is sufficient, and there is no problem that the size of the entire apparatus becomes particularly large.

The embodiment of the present invention has been described in detail above, but this is merely an example, and the present invention can be applied to the production of a thermoplastic resin molded product or a rubber molded product in some cases. Also in the case of (1), after the molding material is injected into the cavity, there is an advantage that the molding material can be prevented from flowing back (backflow) from the cavity to the injection port side.

Further, the present invention can be applied to the production of a molded product which is not particularly required to have high dimensional accuracy and can be applied to a case where a large number of molding dies are taken. It is possible to configure in a form in which various changes are made based on the knowledge of those skilled in the art within the range not to do.

[Brief description of drawings]

FIG. 1 is a front view showing a schematic configuration of a manufacturing apparatus that is an embodiment of the present invention.

FIG. 2 is a schematic plan configuration diagram of the same manufacturing apparatus.

FIG. 3 is a partially cutaway front view of a mold clamping unit, a pressure holding device and a peripheral portion in FIGS. 1 and 2.

4A and 4B are diagrams showing a front structure and a plan structure of the pressure maintaining device in FIG.

5 is a front view showing a main part and a peripheral part of the injection device in FIG. 1. FIG.

FIG. 6 is an operation explanatory view of the device shown in FIGS. 1 to 5;

FIG. 7 is a diagram showing an example of a conventional manufacturing apparatus.

[Explanation of symbols]

 10 Table 14 Mold Clamping Unit 16 Pressure Holding Device 32 Chamber 36 Molding Mold 42 Air Cylinder 54 Extrusion Mechanism 56 Hydraulic Cylinder ,,,, Station

Claims (2)

[Claims] 1. A molding including a chamber for accommodating a molding material, a plunger for extruding the molding material set in the chamber to inject it into a cavity of a molding die, and a mold clamping unit for clamping the molding mold. In an apparatus for manufacturing a product, an extrusion mechanism for applying a predetermined pushing force to the plunger to inject the molding material in the chamber into the cavity by the plunger is provided separately from the plunger and the mold clamping unit, While forming the injection device of the molding material by the pushing mechanism and the plunger, the pressing mechanism for holding the pushing plunger at the pushing position with a predetermined pressing force is in a state separated from the pushing mechanism and An apparatus for manufacturing a molded article, which is fixedly provided on a mold clamping unit, and a pressure holding device is configured by the pressure mechanism and the plunger. 2. A molding including a chamber for accommodating the molding material, a plunger for extruding the molding material set in the chamber to inject it into the cavity of the molding die, and a mold clamping unit for clamping the molding mold. In an apparatus for manufacturing a product, an extrusion mechanism for applying a predetermined pushing force to the plunger to inject the molding material in the chamber into the cavity by the plunger is provided separately from the plunger and the mold clamping unit, While forming the injection device of the molding material by the pushing mechanism and the plunger, the pressing mechanism for holding the pushing plunger at the pushing position with a predetermined pressing force is in a state separated from the pushing mechanism and It is fixedly provided on the mold clamping unit, and the pressure maintaining device is constituted by the pressurizing mechanism and the plunger, and the injection is performed at a predetermined injection station. After the molding material is injected into the cavity of the molding die by the injection device, the molding material in the cavity is kept pressurized by the pressure holding device, and the molding die, the mold clamping unit, and the pressure holding device. Is moved to a molded product take-out station, and the molding material is solidified in the cavity during the moving time.