JPH0720643B2 - Method for forming through-path in body and body manufactured by the method - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method of providing at least one through passage in a solid body and a body produced by the method.

BACKGROUND OF THE INVENTION An example of this type of integral body is a hot runner, which is an element used in combination with an injection molding machine that heats the molding cavity of an injection molding die. It has at least one flow path serving as a plastic supply path. Typically, a hot runner will have only one flow path, which may be straight or slightly slanted if desired. Such a flow path can be easily obtained by drilling. For injection-molded parts that require more complex structures or higher quality adjustments, such as compact discs, FLDs, NODs, and other optical communication means, injection-molded parts are usually manufactured through multiple gates. Must. For this reason, the hot runner needs to be provided such that one inlet opening branches into a number of flow paths, each flow path flowing out to the other side of the hot runner. However, it is clear that the above-mentioned flow path must have a non-linear shape. In the conventionally known technology, these flow paths are provided by performing a large number of external punching machining in the integrated body. In the above-mentioned punching machining, the material is refilled in the portion where the extra drilling is performed. Then you need to fill it.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The drawbacks of the above-described conventional techniques are that it is difficult to adjust the smoothness of the flow channel, and the heating plastic flowing through the flow channel during injection molding is a dead end in the flow channel. Are unavoidable, and the rheological properties of the flow path are not usually as desired. This suggests that there is room for improvement in the products obtained by the known art.

The object of the present invention is to provide a method of the type described above, by means of which the method can be used to make considerable improvements in highly injection molded products.

Means for Solving the Problems In order to achieve the above-mentioned object, the method according to the present invention comprises the following steps.

At least two integral blocks are provided that together form a body of sufficient size.

If necessary, a complementary mold is provided on the corresponding side of the block.

A pair of grooves having a corresponding shape is formed on each of the side surfaces.

The side surfaces are arranged to face each other so that the grooves are combined to form a boundary of one flow path.

Combine the above blocks into one body.

In the above method, the following steps are preferably continuous.

The honing process causes the liquid abrasive to be forced through the channel for a specified period of time to impart the desired rheological shape to the channel. The honing process may be pulsed.

Both blocks can be integrated into one body by any desired technique. However, if the injection molding device is subjected to very high pressure, for example, bolting is not considered. A method in which both blocks are made into one body by vacuum solder welding is preferable.

Most important in determining the required rheological shape is the time interval between passages of the liquid abrasive agent, so-called "slurry honing". this is,
It can be determined by the following procedure.

A large number of bodies are manufactured by changing the above period.

Determine which of the above bodies best corresponds to the desired rheological shape. Then, the time interval of the body is determined.

As a result of the passage of the liquid polishing agent, the wall surface of each flow path is gradually polished, whereby after a specific time elapses,
It should be understood that an "ideal" rheological shape is obtained.

The filled process is also performed by the following process.

The body is divided into longitudinal blocks along a plane that cross-sections the flow path and the shape of the formed groove that defines the flow path in the original body is determined.

If the body to be manufactured is a hot runner, the above-mentioned steps are also carried out by the following method.

Continuously attach hot runners to the injection molding machine.

Each of these hot runners produces at least one injection molded product, such as a compact disc. Then decide which hot runner produced the best product.

For example, in the case of optical information transmission means made of high-quality and transparent plastic, optical characteristics determine which of the manufactured articles is the best. This is done in a number of ways for molded injection molded products.

Further, the present invention provides an integral body having at least one through-flow passage manufactured by using the method according to the present invention described above.

Examples Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an exploded view of the hot runner 1. The hot runner 1 consists of two integral blocks 2 and 3,
Each of these blocks 2, 3 has two parts 2, 4; 3, 5, respectively.
It is composed of. In this embodiment, the integral blocks 2 and 3 are provided with surfaces 6 and 7 which are arranged to face each other.
The grooves 8 and 9 are formed by milling. The groove 8,
9 has the same shape and when the surfaces 6 and 7 are joined together,
They are joined together to form the boundary of the through passage. The blocks 2, 3 and the second parts 4, 5 are respectively joined together and likewise form a linear flow path boundary for receiving a heating element. For this purpose, the surfaces 10 and 11 facing each other,
The grooves 12 and 13 are engraved by milling, for example, and all of these grooves are used as grooves 14 for convenience.

The hot runner 1 has the above-described components as the chain line in FIG.
It is constructed by assembling in the mode shown by 15. Hole 16 and the hole
The positioning pin 17 inserted in the 16 enables accurate positioning. The positioning enables the most accurate joining of both ends of the groove 8. Such highly accurate joining is important in that the streamline shape of the flow path where the boundaries are formed by the grooves 8 and 9 has the required accuracy.

The blocks 2, 3 are made of a material suitable for hot runners, for example high quality tool steel. The blocks 2, 3
The facing surfaces 6 and 7 are formed with high accuracy into flat surfaces.
The grooves 8 and 9 are formed on the surfaces 6 and 7 of the integrated blocks 2 and 3 by milling.

As shown in FIG. 3, after the heating element 29 has been placed in the channel bounded by the groove 14, the integrated blocks 2 and 4, as well as 3 and 5, are joined together by means of screws 18.

FIG. 2 shows a smooth surface 6 of the block 2, which surface 6 is provided with grooves 8 and 9 by milling. Vacuum solder welding bands 19 are provided on the sides of the grooves 8 and 9 and on both ends of the surface 6. The vacuum solder welding zone 19 is provided with nickel, copper, barium, etc. or another appropriate metal, and the surfaces 6 and 7 are arranged to face each other, and heated by eddy current in vacuum, Surface 6 above
It fixes between 7 and 7 very firmly. Since the vacuum solder welding technique is generally known, detailed description thereof will be omitted.

The vacuum welding zone may be composed of paste, wire or foil made of an appropriate material, or a combination thereof.

After assembling the entire hot runner 1 in the manner described above, if necessary, by arranging as shown in FIG. 3, the flow characteristic which is the rheological characteristic of the flow path bounded by the grooves 8 and 9 is set. It is possible to improve the line shape. In the drawing, the flow of the liquid abrasive agent is illustrated very schematically, and normally the abrasive agent, which emerges as a slurry from the storage tank 21, appears in the grooves 8 and 9 by means of a regular reversible pump. It is pressed so as to flow through the flow path where the boundary is formed. Although the above-mentioned technique is a known honing technique in itself, in the present invention, the rheological shape of the flow channel in the integrated body is improved in a very simple manner, and It provides a unique advantage in that it is done.

The outlets 22 and 23 of the flow path are pumped through the filter 34 to the pump 20.
The pump 20 is connected at its other end to an inlet 24. The pulsating pump is pumped for a set period of time so as to reciprocally press and flow the polishing agent slurry in a flow path bounded by the grooves 8 and 9 in a reciprocating manner.

Injection nozzle 25 exits after hot runner 1 is completed
It is connected to 22 and 23. Through these injection nozzles, the heated and thus softened plastic is injected into the molding cavity of the injection molding die.

EFFECTS OF THE INVENTION As described above, according to the present invention, the flow path can be provided in the integral block by a very simple method, and the rheological shape of the flow path can be controlled very precisely. Since the filling degree of the plastic into the molding cavity and the temperature distribution thereof are well controlled, it is possible to manufacture an injection-molded product that is more accurately controlled.

The present invention is not limited to hot runners,
It can also be applied to a metal block with a flow path, and the shape of the flow path is difficult or impossible to form by a simple process such as drilling or milling, and the flow path has a rheological shape. Obviously, it can be applied when providing a flow path that is of essential importance.

The method according to the present invention is not limited to only the shape of the flow channel extending to the common main surface, but a complicated shape, for example,
The spatial shape can be easily implemented.

[Brief description of drawings]

1 is an exploded perspective view of the hot runner, FIG. 2 is a drawing taken along the line II-II of the coupling surface of the hot runner of FIG. 1 to which the injection nozzle is attached, and FIG.
It is a schematic perspective view of a hot runner showing a state in which it is easily formed by honing. 1 ... Hot runner, 2, 3 ... Block, 4, 5 ... Second part, 6, 7 ... Surface, 8, 9 ... Groove, 19 ... Vacuum solder welding band.

Claims (2)

[Claims] 1. At least two blocks, which are connected to each other to form one body, are provided, a pair of grooves of corresponding shapes are formed respectively on the side surfaces of the two blocks, and a positioning pin is formed on the side surface of one block. And a hole into which the positioning pin is inserted on the side surface of the other block, and the side surfaces are arranged so as to face each other so that the grooves are combined to form one flow path. At least one through passage is formed in one body by soldering and welding, and the liquid abrasive substance is reciprocally circulated through the through passage for a certain period of time so that the through passage has a desired rheological shape. A method for forming a through passage in a body, characterized by: 2. A body having at least one through passage manufactured by the method according to claim 1, which is used as a hot runner in combination with an injection molding apparatus.