JPH02122907A - Plastic premolding device - Google Patents

Abstract

PURPOSE:To obtain the molded object having small strain and high accuracy by forming the flowing port of the nozzle for premolding into the shape of the premolded object having the shape approximate to a perfect object. CONSTITUTION:Plasticized resin is premolded in premolding part 6 without being biased at low pressure through a nozzle 16. After a top force 3 has been lowered more or less, the flank 8 in the premolding part 6 is forcedly fed in the cavity of a bottom force 4 by operating an ejecting part 13. Simultaneously, the molded object 9 in a molded object-delivering part is transferred to next process, and is taken out. The flank 8 having been formerly fed in the bottom force 4 is pressurized and molded by the mold-closing operation of a molding cylinder 12. When the resin molded along the shape of the flowing port 34 of the plasticized resin in the tip of the nozzle 16, is cut, it becomes a flank 8, and the premolded flank approximate to a perfect object is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a plastic molding apparatus, and particularly to a molding apparatus including a preforming process.

[Conventional technology]

Fill the molten resin while moving the nozzle into the recess of the mold,
The one that later clamps the mold is 1, for example, JP-A-60-1.
It is described in Publication No. 62614.

[Problem to be solved by the invention]

The method described in the above-mentioned publication is excellent in that the concave portion of the mold is filled with resin almost uniformly, but it requires complicated movement of the nozzle and is expensive. Another problem is that the distance from the molding machine to the nozzle is long, and the resin cools during the flow path process, causing the resin to clog the flow path.

Furthermore, in order to compensate for the injection pressure loss that inevitably occurs due to flowing through a narrow and long channel, it is necessary to apply injection pressure to the resin that is higher than necessary.

As a result, the internal strain of the resin increases, reducing the precision of the molded product, and at the same time, the specifications and size of the molding machine become unnecessarily large.

Since the flow direction is unidirectional, the flow direction is also strong.

An object of the present invention is to provide a molding apparatus that does not apply unnecessary stress during the molding process in order to obtain a highly accurate molded product with small distortion.

[Means to solve the problem]

The above purpose is to plasticize the material stored in the hopper, preform it using a nozzle, and transport the preformed product to the main mold for main forming, in which the outlet of the preforming nozzle is connected to the finished product. This is achieved by forming a preform into a shape that approximates the shape of the preform.

In preforming, in particular, (1) the shape of the material outlet at the tip of the nozzle is configured to match the shape of the molded product;

The purpose is to create a preformed blank that approximates the final shape of the molded product by appropriately setting the arrangement, number, size, etc.

(2) Furthermore, the plasticized material is supplied according to the shape of the molded product, (3) the outflow direction of the preformed material is regulated on the mold surface, and (4)
) By providing a cutting function for the supplied material, etc.
achieved.

[Operation] The internal strain in the resin of the blank, which is preformed without deviation under low pressure, is small and stable.

Furthermore, since the product is preformed to approximate the finished product, the flow distance during pressure molding is short and uniform.

Therefore, processing distortion of the molded product is small and uniform, and high-precision molding is possible.

In order to obtain a blank that approximates the shape of the final molded product, the shape, arrangement, number, size, etc. of the material outlet at the tip of the nozzle can be arbitrarily set, and a preformed blank can be obtained at the same time as the material flows in. did.

Furthermore, it is also possible to provide the mold with the functions of guiding and cutting the supplied material.

As described above, by appropriately and arbitrarily changing the flow rate and location of the material, a preformed blank that approximates the finished product can be molded at extremely low pressure, making it possible to perform high-precision molding.

〔Example〕

Embodiment (1) of the present invention will be described below with reference to FIGS. 1 to 5.

First, in FIG. 1, a guide 10 is placed on the top surface of the base 1.
．． Lower mold 4. Slider cylinder 11. A pedestal 2 is assembled. A transfer section 5 having a preformed section 6 and a molded product receiving section 7 is slidably assembled to the slider cylinder 11 via a mounting plate 22 . 61 is a preformed cavity formed in the transfer section 5.

The pedestal 2 has an upper mold 3. Forming cylinder 12. A molding section set consisting of an eject section 13 and a nozzle section 16 in contact with the upper surface of the transfer section 5. Heating cylinder 23, heater 15. A hopper 19 is installed.

At the center of the hopper 19 is a stirring frame 17 that is rotated by a motor 20. A screw 14 is incorporated. The transfer section 5 shown in FIG. 2 includes a preforming section 6. Molded product receiving part7. The escape holes 21 of the molding die are arranged at appropriate pitches.

Next, the operation will be explained.

The material 18 in the hopper 19 is stirred by a stirring frame 17 that is rotated by a motor 20, and is sent into a heating cylinder 23 by a screw 14. Since the heating cylinder 23 is heated to an appropriate temperature by the heater 15, the material 18 sent therein is plasticized.

As shown in FIG. 3, the plasticized resin is transferred to the nozzle 16
It is preformed into the preforming section 6 at low pressure without any deviation.

This preforming also serves as accurate metering.

At the same time, the ejector 13 is operated to eject the molded product 9 that has been molded in the previous cycle into the molded product receiver 7. When both operations are completed, the transfer part 5 is slid by the slider cylinder 11 as shown in FIG. The molded product is transferred to the molded product transfer section 10.

Here, the blank 8 in the preforming part 6 is forcibly fed into the cavity of the lower mold 4 by operating the eject part 13 after lowering the upper mold 3 slightly. At the same time, the molded product 9 in the molded product transfer section is taken out and carried out to the next process.

Next, as shown in FIG. 5, the transfer part 5 is slid and retreated by the slider cylinder 11 until the escape hole 21 of the mold is aligned with the mold position. Then, by the mold clamping operation of the molding cylinder 12, the blank 8 previously fed into the lower mold 4 is pressurized and molded.

After the molding and cooling time has elapsed, the molding cylinder 12 rises and the upper die 3 rises. At that time, the molded product attaches to the upper mold 3 and rises.

After opening the mold, the transfer section 5 retreats to the origin position (right end in FIG. 1) and moves to the next cycle.

When the transfer section 5 is at a position other than the origin, the upper surface of the transfer section 5 and the tip of the nozzle section 16 are always in contact to prevent plasticized resin from leaking from the tip of the nozzle section 16. It has become. Upper mold 3. Lower mold 4.
In some cases, a cooling or heating flow path may be provided at the upper part of the preforming part 6 of the transfer part 5 and the heating cylinder 23.

Next, the shape of the outlet 34 of the nozzle 16 will be explained based on FIG. The upper part shows the shape of the plasticized resin outlet 34 at the tip of the nozzle 16, and the lower part shows the shape of the finished product formed by the nozzle.

When the resin molded along the shape of the outlet 34 is cut, a blank 8 is obtained, which is a preformed blank that approximates the finished product.

In FIG. 6, (a) shows an example of molding a cylinder, (b) a triangular prism, (c) a flat plate, (d) a cylinder, and (e) a cruciform prism.

It is clear that there are many shapes of the outlet 34 other than this example.

In particular, the cylindrical preform blank has a narrow r
After passing through the "3", it is welded again and becomes as if it were a single piece. The pieces that receive the preformed blanks are also of the same shape to improve blank accuracy and maintain it.

Next, FIG. 7 will be explained. The molten resin heated and plasticized by the heater 15 is molded along the shape of the outlet 34 of the nozzle 16 to become a preformed material 35. In order to prevent the temperature of the preformed material 35 from decreasing, the atmosphere may be kept at an appropriate temperature.

Next, FIG. 8 will be explained. For example, in FIG. 7, when the preformed material 35 is flowed out, the material may meander.

Therefore, in order to correct the meandering of the material, the mold is closed to an appropriate height and the machined surface of the mold is utilized.

After an appropriate amount of the preformed material 35 has flowed out, the upper mold 3 is lowered, and the preformed material 35 is cut using the piece surface of the mold and the tip of the nozzle 16, or the piece surface of the lower mold 4. Pressure and form.

At this time, the piece surface of the upper die 3 shields the outlet 34 of the nozzle 16.

Next, FIG. 9 will be explained. Preformed material 35,
By rotating the wire 37 stretched by the pin 36, it is cut and a blank 8 is made. This cutting function is built into the material supply port or the mold.

Next, FIG. 10 will be explained. A material supply section located above the lower mold 4 moves according to the shape of the molded product under NC control. The resin plasticized by the heat of the heater 15 is supplied from the nozzle 16 as a preformed material 35 . This preformed material 35 approximates the final shape of the molded article.

According to this embodiment, (1) When the plasticized molding material passes through the outlet of the nozzle, it is preformed to approximate the final shape of the molded product, so it is simple. At the same time, the flow distance of the molding material during pressure molding is short and uniform.

(2) Similarly, since preforming is performed at low pressure, internal distortion is small and precision molding is possible.

(3) Thin plates for forming preformed materials at low pressure.

It is advantageous for forming long, thin, and thick products.

There are effects such as

〔Effect of the invention〕

As described above, according to the present invention, a material stored in a hopper is plasticized, preformed by a nozzle, and the preformed product is conveyed to a mold for main molding for main molding. In particular, since the outlet of the nozzle was formed in a shape that would become a preformed product with a shape similar to that of the finished product,
The present invention has the advantage that it is possible to easily mold a preformed material having a shape similar to a molded product at low pressure, and that an inexpensive and small-sized precision molding device can be provided.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a molding device showing an implementation configuration of the present invention;
FIG. 2 is a plan view of the transfer section, FIGS. 3 to 5 are partially sectional side views showing the operating state of the transfer section,
FIG. 6 is a plan view and a blank perspective view showing the shape of the nozzle outlet, FIG. 7 is a perspective view showing the nozzle part of another embodiment, and FIG.
9 is a perspective view of the cutting mechanism, and FIG. 10 is a partially sectional side view of an embodiment using an NC control nozzle. 1... Base, 2... Frame, 3... Upper mold, 4...
- Lower mold, 5... Transfer part, 6... Preforming part, 7... Molded product receiving part, 8... Blank, 9... Molded product, 10... Guide. DESCRIPTION OF SYMBOLS 11...Slider cylinder, 12...Forming cylinder, 13...Eject part, 14...Screw, 15...
... Heater, 16 ... Nozzle part, 17 ... Stirring bar,
18...Material, 19...Hopper, 20...Motor, 21...Escape hole. 22... Mounting plate, 23... Heating cylinder, 24... Member, 25... Supply port, 26... Slit portion, 27...
・Preforming unit, 28...molding unit, 29・
...Blank supply unit, 30... Molded product take-out unit, 31... Chain, 32... Taber part, 33
...hand, 34...outlet, 35...preformed material, 36...pin, kudzu 1/-m-base 2-keise 3-yo main 4-bottom! 5-1 Transfer 6- Ziling i Shunken 7- Molded product receiving part 3- Blank q-, Ornohin capital 2 $3 Gu rod diagram Kyoto diagram tea S Figure 9 Yo δ 70th

Claims (1)

[Claims] 1. In the case where the material stored in the hopper is plasticized, preformed using a nozzle, and the preformed product is transported to the main molding mold for main forming, the outlet of the preforming nozzle is connected to the finished product. 1. A plastic preforming device, characterized in that it is formed into a preformed product having a shape similar to that of .