KR19990020316U - Core guide structure of mold base - Google Patents

Abstract

The present invention discloses a core guide structure of a mold base. In the core guide structure of the conventional mold base, deformation occurs due to the displacement of the first core pin and the second core pin due to the flow of the core, or breakage occurs in severe cases, and scratches of the core occur, resulting in injection molded articles. It acted as a cause of the defect. According to the present invention, a plurality of positioning holes are formed in a substantially rectangular shape in a cavity of a fixed template, and a plurality of positioning protrusions having a chamfered surface are formed on the upper surface of the core so as to be fitted in a corresponding relationship with each other. The protruding height of the positioning protrusions is greater than the protruding height of the first core pin. Therefore, the positioning protrusions are prevented from flowing in the core by being fitted into the positioning holes, and the position thereof is accurately determined so that deformation and breakage of the first and second core pins are effectively prevented. Workability is remarkably improved, such as being removed.

Description

Core guide structure of mold base

The present invention relates to a mold base for injection molding, and more particularly, to a core guide structure of a mold base to prevent the flow of the core and to accurately determine the position.

Injection molding is a method of manufacturing a product having a predetermined shape and dimension by injecting a molten molding material, for example, a thermoplastic resin, into a cavity of a mold base, and injection molding is generally performed automatically by an injection molding machine. The mold base required for injection molding is configured to be divided into a pair of fixed and movable templates.

Looking at one example of such an injection molding method, the injection molding machine is a heating cylinder for melting a molding material supplied from a hopper by heating, and a mold base for molding a molding material in a molten state by heating of the heating cylinder. Can be divided into The mold base is configured such that a pair of stationary and movable templates have cavities on their parting line. Here, the cavity is usually formed in the dividing surface of the stationary template, the stationary template is fixed to the heating cylinder, and the cavity is selectively opened and closed by the operation of the movable template. The movable template is actuated by the operation of the clamp mechanism, and the injection molding machine is equipped with an eject mechanism for removing the molded article in the molded state from the cavity of the mold base.

Therefore, when a predetermined time elapses after the molten molding material is injected into the cavity by heating the heating cylinder while the cavity is closed by the operation of the movable template, the cavity is opened by the operation of the movable template and ejected. The injection-molded article molded by the operation of the mechanism is pushed out of the cavity and then solidified to produce a desired article.

Injection molding, on the other hand, can produce a variety of different types of objects, such as panels, boards, boxes, and cylindrical containers, and electronics such as video cassette recorders (VCRs) and compact disc players (CDPs). It is used for manufacture of a cover. As an example of an electronic product, in the case of a video cassette recorder, a chassis and a front panel are manufactured by injection molding, and bosses, pins, holes, etc. are formed in the chassis and the front panel of the video cassette recorder.

In the conventional mold base as shown in FIGS. 1A and 1B, the mold base 10 has a fixed template 12 assembled to one side of the fixed mounting plate 11, and the divided surface of the fixed template 12 is formed on the divided surface of the fixed template 12. The cavity 13 is formed. In the mold base 10, a space block 15 and a movable template 16 are assembled to one side of the movable mounting plate 14, and a core mounting hole 17 is formed in a divided surface of the movable template 16. do. The core 18 is provided in the core mounting hole 17 of the movable template 16, and the core 18 is fitted to the cavity 13 of the stationary template 12 to form the desired injection molded product P. Is achieved.

In addition, upper and lower contact plates 19 and 20 are respectively mounted at the center of one surface of the movable template 16, and eject pins 21 are mounted at one side of the lower contact plate 20, and the other of the lower contact plate 20 is provided. A return pin 22 is attached to the side, and a spring 23 for imparting a predetermined elastic force is attached to the outer circumferential surface of the return pin 22.

In addition, the guide pin bush 24 is disposed and mounted on the fixing template 12, and the guide pin 25 is fitted to the core 18 in a corresponding relationship with the guide pin bush 24. Are mounted. The core 18 is fitted to the cavity 13 by fitting the guide pins 25 into the guide pin bushes 24 correspondingly to each other.

On the other hand, a plurality of first core pins 26 are mounted to the cavity 13 of the fixed template 12 so that a plurality of second core pins 27 are provided on one side of the core 18. The first core pins 26 are mounted to correspond to each other. At the end of the second core pin 27, a guide hole 28 through which the first core pin 26 is guided and fitted is formed, and the first core pin 26 is a guide hole 28 of the second core pin 27. The cores 18 are fitted to the cavities 13 of the stationary template 12 in a corresponding relationship by being guided and fitted into each other.

By the way, the core guide structure of the conventional mold base as described above has a problem of being easily shifted when the first core pin 26 is guided and fitted into the guide hole 28 of the second core pin 27. That is, the position of the core 18 is determined by fitting the guide pins 25 to the guide pin bushes 25 so as to fit the cavity 13, but due to the flow of the core 18, the first core As the relative positions of the pins 26 and the second core pins 27 are shifted, the first core pins 26 do not fit into the guide holes 28 and are caught. In particular, the mold base 10 causes severe flow of the core 18 due to wear of the guide pin bushes 24 and the guide pins 25 by the fixed and movable template 12, 16 being repeatedly opened and closed. do.

Thus, deformation of the first and second core pins 26, 27 occurs or, in severe cases, breakage occurs. In addition, as the first core pin 26 contacts the surface of the core 28, scratches of the core 18 may occur, and thus, the first core pin 26 may act as a cause of failure of the injection molded product P.

In addition, when the first and second core pins 26 and 27 are deformed and broken, the workability is remarkably degraded, such as unnecessary work time due to replacement or modification of the mold base 10. The problem is exacerbated when using relatively small diameter first and second core pins 26, 27.

The present invention is devised to solve the conventional problems as described above, an object of the present invention is to prevent the flow of the core by a simple configuration and structure, as well as the core guide structure of the mold base so that its position is accurately determined To provide.

1a and 1b is a cross-sectional view showing a conventional mold base,

2 is a cross-sectional view showing a core guide structure of a mold base according to the present invention;

3 is a plan view showing a core guide structure of a mold base according to the present invention;

4a and 4b is a perspective view and a cross-sectional view partially showing the core guide structure of the mold base according to the present invention.

♣ Explanation of symbols for the main parts of the drawing ♣

30: mold base 31: fixed mounting plate

32: fixed template 33: cavity

34: movable mounting plate 36: movable template

38: core 46, 47: first and second core pins

50: positioning hole 51: positioning projection

52: Chamfered surface P: Injection molded product

A feature of the present invention for achieving the above object is a movable plate which is assembled to have a cavity on one side of the fixed mounting plate, and a core which is assembled to one side of the movable mounting plate and fitted to the cavity of the fixed plate. In a mold base having a template and first and second core pins for forming protrusions in an injection molded article, a plurality of positioning holes are formed in a substantially rectangular shape in the cavity of the stationary template, and located on an upper surface of the core. The plurality of positioning protrusions having a chamfered surface are formed to protrude so as to fit in a corresponding relationship with the crystal holes, and the protrusion height of the positioning protrusions is in the core guide structure of the mold base that is formed larger than the protruding height of the first core pin. .

Hereinafter, one preferred embodiment of a core guide structure of a mold base according to the present invention will be described in detail with reference to the accompanying drawings.

2 to 4a and 4b is a view showing for explaining the core guide structure of the mold base according to the present invention.

First, as shown in FIG. 2 and FIG. 3, the mold base 30 is provided with the fixed mounting plate 31 on the heating cylinder of the injection molding machine described above, and the fixed template 32 on one side of the fixed mounting plate 31. Assembled by this fastening, the cavity 33 is formed in the dividing surface of the stationary template 32.

In the mold base 30, the movable mounting plate 34 is attached to the clamp mechanism of the injection molding machine, and the space block 35 and the movable template 36 are assembled to one side of the movable mounting plate 34 by fastening, respectively. The core mounting hole 37 is formed in the divided surface of the movable template 36, and the core 38 is provided in the core mounting hole 37 of the movable template 36. As shown in FIG. The core 38 is fitted in a relationship corresponding to each other in the cavity 33 of the stationary template 32 to form the desired injection molded article P. At this time, the movable mounting plate 34 is moved by the clamp mechanism to open or close the cavity 33 of the stationary template 32. In this way, when the molding material in the molten state is injected from the heating cylinder into a shape in which the cavity 33 and the core 38 are fitted, a desired injection-molded article P is produced.

In addition, upper and lower contact plates 39 and 40 are respectively mounted at the center of one surface of the movable template 36, and eject pins 41 are mounted at one side of the lower contact plate 40, and the eject pins 41 are ejected. The molded article P is pushed out of the cavity 33. At this time, the space in which the upper and lower plates 39 and 40 can move upward and downward is secured by the space block 35. A return pin 42 is mounted on the other side of the lower plate 40, and a spring 43 for imparting a predetermined elastic force is mounted on the outer circumferential surface of the return pin 42, and the return pin 42 is fixed and movable template ( When the 32 and 36 are closed, the upper and lower plates 39 and 40 are returned to their initial positions.

A plurality of guide pin bushes 44 are disposed and mounted on the fixed template 32, and a plurality of guide pins 45 are inserted into the core 38 so as to be fitted in a corresponding relationship with the guide pin bushes 44. Is mounted. The core 38 is fitted to the cavity 33 by fitting the guide pins 45 in a corresponding relationship to the guide pin bushes 44. That is, the guide pin bushes 44 and the guide pins 45 serve as guides for precisely fitting the fixed and movable templates 32 and 36, where the guide pin bushes 44 and the guide pins 45 are provided. ) Are about four used.

Meanwhile, a plurality of first core pins 46 protrude from the cavity 33 of the fixed template 32, and a plurality of second core pins 47 are provided on one side of the core 38. The pin 46 is mounted to correspond to each other. At the end of the second core pin 47 is formed a guide hole 48 through which the first core pin 46 is guided and fitted, and the first core pin 46 is a guide hole 48 of the second core pin 47. The core 38 is fitted to the cavity 33 of the stationary template 32 in a corresponding relationship by being guided and fitted into each other. These first and second core pins 46 and 47 are mounted to form projections (or protrusions) such as bosses Pb on the injection molded product P.

As shown in Figs. 3, 4A, and 4B, a plurality of positioning holes 50 are formed in the inner surface of the cavity 33 of the fixed template 32 in a substantially rectangular shape. In addition, the positioning protrusions 51 protrude in a substantially rectangular shape on the upper surface of the core 38 so as to be fitted in a corresponding relationship with the positioning holes 50 of the fixed template 32 to prevent the flow of the core 38. Is formed. Chamfering surfaces 52 are formed on both upper portions of the positioning protrusions 51 so as to be smoothly fitted into the positioning holes 50.

On the other hand, the protruding height of the positioning protrusions 51 is formed larger than the protruding height of the first core pin 46. That is, the positioning protrusions 51 have a protruding height such that the first core pin 46 is fitted to the positioning holes 50 earlier than the first core pin 46 is fitted to the guide hole 48 of the second core pin 47. will be. Here, the protruding height of the positioning protrusions 51 is preferably formed to be about 5 mm larger than the protruding height of the first core pin 46.

Although the positioning protrusions 51 are shown to protrude from the upper surface of the core 38, the positioning protrusions 51 may be formed in the cavity 33 of the fixed template 32. Thus, when the positioning projection 51 is formed in the cavity 33 of the fixed template 32, it is natural that the positioning holes 50 should be formed on the upper surface of the core 38.

In addition, although the positioning holes 50 and the positioning protrusions 51 were shown to be formed in the position corresponding to each other, these positions and numbers can be formed by changing suitably as needed. In addition, although one core 38 was shown installed in the core installation hole 37 of the movable template 36, it is easily understood that a plurality of cores 38 can be installed according to the injection molded product P. It is possible.

Looking at the operating state of the mold base 30 as described above, as the movable mounting plate 34 is moved by the operation of the clamp mechanism, the guide pins 45 correspond to each other with respect to the guide pins 44. While being fitted, the cavity 33 of the stationary template 32 is closed by the movable template 36. Subsequently, in the process of moving the movable mounting plate 34, the positioning projections 51 of the core 38 are fitted into the positioning holes 50 of the cavity 33 in a corresponding relationship with each other. The flow of the core 38 is prevented and its position is accurately determined.

In this process, the first core pin 46 is accurately guided and inserted into the guide hole 48 of the second core pin 47, thereby preventing deformation and breakage of the first and second core pins 46 and 47. do. In addition, the phenomenon in which the core 38 is scratched by the first core pin 46 is prevented, so that the cause of failure of the injection molded product P is eliminated, and the deformation and breakage of the first and second core pins 46 and 47 are prevented. Unnecessary work time due to this can be eliminated and workability is remarkably improved. In particular, the present invention effectively prevents their deformation and breakage even when the first and second core pins 46 and 47 are made thin and long.

On the other hand, the above-described embodiment is merely to describe one preferred embodiment of the present invention, the scope of application of the present invention is not limited to such, and can be changed appropriately within the scope of the same idea. For example, the shape and structure of each component specifically shown in the embodiment of the present invention can be modified.

As described above, according to the core guide structure of the mold base according to the present invention, the positioning projections are inserted into the positioning holes to prevent the flow of the core and the position thereof is accurately determined so that the first and second cores are accurately determined. Since deformation and breakage of the pin are effectively prevented, workability is remarkably improved, such as the cause of defects in the injection molded article is eliminated.

Claims (1)

A stationary template assembled to have a cavity on one side of the stationary mounting plate, a movable template on which a core assembled to one side of the movable installation plate and fitted to the cavity of the stationary template is installed; In a mold base having a first and a second core pin, A plurality of positioning holes 50 are formed in a substantially rectangular shape in the cavity 33 of the fixed template 32, A plurality of positioning protrusions 51 having a chamfer 52 are projected to be fitted to the upper surface of the core 38 in a corresponding relationship with the positioning holes 50, Protruding height of the positioning projections (51) is the core guide structure of the mold base, characterized in that formed larger than the protruding height of the first core pin (46).