JPH09225947A - Manufacture of molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a molding die for a molded product of polyhedral body structure by turning the surfaces of respective split cores to be split in compliance with respective turning areas, and then integrating respective split cores all together and finishing the surfaces. SOLUTION: In the case a molded product is a multilens of dome type, a molding die is constituted of a top force 3 and a bottom force 4, and core sections of the bottom force 4 are formed as an assembly of a plurality of split cores 40 to be split in the direction in parallel with the opening and closing direction of the molding die. Then the split cores 40 are set in a jig, and recessed spherical faces 45 forming a molding face of a lens are formed on the end faces of the split cores 40. Then the split cores 40 are released from the jig and combined together and fitted into an outer frame section 41 and integrated thereon, and protruded and curved faces 44 forming a molding face of the inner face of the dome are integrated with the split cores 40 by a precision NC lathe or an engraving discharge machining, and finished into mirror faces crossing the adjacent split cores 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molding die for molding a molded article having a polyhedral structure.

[0002]

2. Description of the Related Art In an infrared sensor, a single infrared detecting element can detect infrared rays from various directions.
A dome type multi-lens as disclosed in Japanese Patent No. 242304 is required. This is a large number of lenses arranged in a dome shape, and an example thereof is shown in FIG. A plurality of types of spherical lenses 21, 22, 23 are integrally formed on the inner surface side of the dome 1 having a spherical outer surface having a radius R. Four spherical lenses 21 are arranged so as to surround the center of the dome 1.
Out of the rectangular outer shape of each spherical lens 21, two spherical lenses 22 are arranged on each outer side of the side portion, and eight spherical lenses 22 are arranged on each outer side of the corner portion, and four spherical lenses 22 are disposed on each outer side of the corner portion. Lens 2
3 are arranged. These spherical lenses 21, 2
2 and 23 are designed to form an image of an object whose focal length is at the center O of the dome 1 at a predetermined distance ahead. In the figure, 19 is a hook for mounting the multi-lens.

[0003]

It is suitable for mass production to manufacture the above-mentioned multi-lens having such a polyhedral structure as a molded product by a molding die, but since it has a polyhedral structure, the molding die is manufactured. Is difficult. In particular, in the case of the multi-lens for the infrared sensor, the required accuracy is high and the radius R is very small, around 10 mm, which makes it even more difficult to manufacture.

The present invention has been made in view of the above circumstances, and an object thereof is to manufacture a molding die for easily manufacturing a molding die having a polyhedral structure. There is a way to provide.

[0005]

SUMMARY OF THE INVENTION In the present invention, however, each of the split cores is formed as a split core whose surface is split according to each turning region in a direction parallel to the opening / closing direction. It is characterized in that the surface of each of these split cores is subjected to turning processing, and then the processing of finishing the surface by integrating each split core.

It is preferable that the processing for finishing the above-mentioned surface is to form a surface that straddles the adjacent split cores, or is a mirror surface processing. The turning process applied to the surface of each split core is preferably performed by setting the split core in a jig that holds the split core at a specific position, and particularly the jig holds a plurality of split cores at symmetrical positions. It is preferable that it is one.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described. When the molded product is a dome-shaped multilens as described above, the molding die is an upper die 3 as shown in FIG. The lower mold 4 is composed of a plurality of split cores 40 that are split in a direction parallel to the opening / closing direction of the molding die. In the figure, reference numeral 41 is an outer frame portion that holds a plurality of split cores 40, and 42 is a spacer.

When dividing the lower die core part,
Consider the dividing line when designing the multi-lens. For example, a dome-type multi-lens in which a plurality of lenses 2 are provided on a dome 1 having a planar shape as shown in FIG. 4 is, in addition to the optical point, a molding die processing and an assembly surface. , A straight line, a straight line L, and a right angle at the intersection of the split lines L, and the adjacent lenses 2 from the viewpoint of the molding surface.
The arrangement of the lens 2 is determined so as to satisfy the condition that the thicknesses (heights) at the positions of the two dividing lines are equal.

The dividing core 40 is divided by a straight line or the dividing line L of each lens 2 is made straight.
In order to facilitate the processing and assembly of each of the split lines L, each split core 40 has at least one right-angled corner portion by forming the intersection of the split lines L at a right angle. This is because 40 is provided. The thickness (height) of the adjacent lenses 2 and 2 at the position of the dividing line L is made equal for the following reason. That is, when the lenses 2 and 2 are overlapped as shown in FIG. 5, if they are divided along the division line A or C, the thickness of both lenses 2 and 2 at the position of the division line L as shown in FIGS. Although the (height) will be different, when the resin flow at the time of molding is in the direction of the arrow F shown in the figure, and in the case shown in FIG. This is because the shape collapses due to
In the case shown in (c), the shape collapses when the flow direction F of the resin is reversed, and in order to avoid this, the state shown in FIG. So that However, if the change in thickness inevitably occurs, the resin flow direction F is taken into consideration, and the resin is set to flow from the thicker side to the thinner side as shown in FIG. 6C.

When the dividing line L is determined as described above, the core portion of the molding die is also a combination of a plurality of split cores 40 divided by the dividing line L in parallel with the opening / closing direction of the molding die. When manufacturing the core portion, as shown in FIG. 2, individual split cores 40 are formed, and in parallel with this, a concave spherical surface 45 serving as a molding surface of the lens 2 is formed on the surface of each split core 40 of the split cores 40. A jig 8 used for turning is formed, and with the split cores 40 set in the jig 8, a concave spherical surface 45 serving as a molding surface of the lens 2 is turned on the surface of each split core 40, and thereafter. , These split core 4
The surfaces of all the split cores 40 are collectively finished so as to be along the inner surface of the dome 1 in a state where they are combined and integrated with each other.

In manufacturing each of the split cores 40, the horizontal cross-sectional shape of the split core 40 having the contour line of the core portion and the split line L as the contour line is obtained for each split core 40, and at the same time,
The outer shape is determined according to the method of assembling and fixing each split core 40, and the numerical data of the lens 2 to be formed on the upper end surface of each split core 40 is obtained. This numerical data is
Explaining the case of the model shown in FIG. 7, it is the vertex angle α, the azimuth angle β, the principal point position A, the lens curvatures C and D, and the base thickness E.

Then, the split core 40 having the above-mentioned outer shape is manufactured. Wire-cut electric discharge machining can be preferably used for this production. In this case, as shown in FIG. 8, a plurality of split cores 40 may be laid out on the material 7 to produce. Reference numeral 77 in the figure denotes a pressing margin for pressing and fixing the material 7. In addition, when the method of assembling and fixing each split core 40 is performed by forming the split core 40 with a step or by fixing the split core 40 with a bolt, the step portion 46 and the screw hole 47 formed in the split core 40 have the above layout. Is formed first along with, and thereafter, each split core 40 is formed by electric discharge machining. Although FIG. 8 is provided with a step portion 46,
In the portion where the groove 70 for forming the step portion 46 is processed, a block 71 of the same material is inserted and fixed in order to equalize the water resistance and the processing resistance at the time of wire cut electric discharge machining. To do. The tip surface of the split core 40, which is the molding surface of the lens 2 at this point, may have any shape.

After the split cores 40 are formed in this manner, the split cores 40 are set on the jig 8 and the concave spherical surface 45 serving as the molding surface of the lens 2 is turned on the tip surface of the split cores 40. At this time, since the split core 40 is split along the split line L parallel to the opening / closing direction of the molding die, the split core 40
The concave spherical surface 45 formed on the tip surface of the has an elliptical shape when viewed from the longitudinal direction of the split core 40, and the set position of the split core 40 in the jig 8 is the position shown in FIG. 9 and corresponds to the lens curvature D. The concave spherical surface 45 is formed on the tip surface of the split core 40 by turning the spherical surface to be turned with a precision NC lathe or the like. At this time, the straight portion 80 is provided on the upper surface of the jig 8, and the height dimension of the split core 40 is controlled by the processing depth d of the spherical surface from the upper surface of the jig 8. The height H of the jig 8 is set to be 2 to 3 mm larger than the required height of the split core 40.

The split cores 40 are set on the jig 8 by holding holes 81 in the jig 8 which have the same horizontal sectional shape as the split core 40.
Is provided and the split core 40 is fitted into the holding hole 81. The holding hole 81 may be formed by wire cut electric discharge machining. Further, as shown in FIG. 10, the jig 8 holds a plurality of split cores 40 at symmetrical positions, so that the concave spherical surface 45 can be turned with respect to the plurality of split cores 40 at once. The jig 8 may be manufactured according to the difference in the radius of curvature of the lens. When the jig 8 is for a multi-lens having three types of curvature radius,
It is only necessary to manufacture three types of jigs 8. In addition, the tip end surface of the split core 40 has not only the concave spherical surface 45 that is the molding surface of the lens 2 but also the split line L that is a straight line. Therefore, the radius of curvature that is the molding surface of the inner surface of the dome 1 is as described above. It is necessary to provide a convex curved surface 44 larger than the radius of curvature of the concave spherical surface 45. However, during this turning, the convex curved surface 44 is ignored and the turning is performed.

After forming the concave spherical surface 45 on each of the split cores 40 as described above, the split cores 40 extracted from the jig 8 are combined as shown in FIG. 11 (a) and fitted into the outer frame portion 41. In this state, the convex curved surface 44 serving as the molding surface of the inner surface of the dome 1 is integrally machined to these split cores 40 by a precision NC lathe or a die-sinking electric discharge machining, and adjacent as shown in FIG. 11 (b). A mirror surface that straddles the split core 40 is finished. If a draft is required, it will be integrally processed.

FIG. 1 shows a split core 4 formed in this way.
FIG. 12 is a perspective view and a broken perspective view of a state in which the 0 group, the outer frame portion 41, and the spacer 42 are combined, and FIG. 12 is an exploded perspective view. Further, the split core 40 is shown as being fixed with only bolts. In the figure, 48 is a hole for ejector pin, 49
Is a forming portion of the mounting hook 19 of the dome 1. FIG. 13 is a perspective view and a broken perspective view of an example in the case of further stepping, and FIG. 14 is an exploded perspective view thereof.

In the case of the above-mentioned multi-lens, the inner surface of the upper mold 3 is a simple spherical surface, so that it can be a split mold having a hemispherical concave portion finished into a mirror surface as shown in FIG. It suffices if the above-mentioned draft portion 30 of the upper die 3 is formed by electric discharge machining using the electric discharge machining electrode 35 shown in FIG.

[0018]

As described above, according to the present invention, the molding die is formed as split cores whose surfaces are split according to the respective turning regions in the direction parallel to the opening / closing direction. The surface of each split core is turned, and then the split cores are integrated to finish the surface. In addition to splitting into multiple split cores,
Since the splitting direction is parallel to the opening / closing direction of the molding die, and the surface of each split core is turned, it is easy to manufacture split cores. Although it was divided to combine with the above to finish the surface, in the end it is possible to obtain the same finish as the integral one, and the production of the molding die for obtaining the molded product of the polyhedral structure is possible. It's easy.

It is preferable that the above-mentioned processing for finishing the surface is to form a surface that straddles the adjacent split cores or mirror-finishing in order to obtain a good molded product. Further, it is preferable that the turning process applied to the surface of each split core is performed by setting it on a jig that holds the split core at a specific position from the viewpoint of easy accurate turning process.
In particular, it is preferable that the jig holds a plurality of split cores at symmetrical positions, because turning processing can be performed on the plurality of split cores at once.

[Brief description of drawings]

FIG. 1 shows an example of a lower mold obtained by the present invention, (a) is a perspective view and (b) is a cutaway perspective view.

FIG. 2 is a flowchart of a manufacturing method according to the present invention.

FIG. 3 is a vertical sectional view of an example of a molding die.

FIG. 4 is an explanatory diagram of an example of division lines.

FIG. 5 is an explanatory diagram of division positions.

6 (a), (b) and (c) are explanatory views of a difference in sectional shape due to a difference in division position.

FIG. 7 is an explanatory diagram of data required for a split core.

8A and 8B show an example of production of a split core by wire cut electric discharge machining, in which FIG. 8A is a plan view and FIG. 8B is a side view.

FIG. 9 is an explanatory diagram of a jig.

FIG. 10 is a perspective view of a jig and split cores set on the jig.

FIG. 11A is a perspective view of a split core before finishing, and FIG.
FIG. 4 is a perspective view of a split core after finishing.

FIG. 12 is an exploded perspective view of a lower mold obtained according to the present invention.

FIG. 13 shows another example of the lower mold, (a) is a perspective view, and (b) is
Is a cutaway perspective view.

FIG. 14 is an exploded perspective view of the above.

FIG. 15 is an exploded perspective view of the upper mold.

FIG. 16 is a perspective view showing an example of a method of processing the upper die.

FIG. 17 shows a dome-shaped multilens as an example of a molded product having a polyhedral structure, (a) is a plan view, and (b) is a sectional view.

[Explanation of symbols]

 L division line 40 division core 45 concave spherical surface

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kimi Okugawa 1048, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (5)

[Claims] 1. A molding die is formed as divided cores whose surfaces are divided according to respective turning regions in a direction parallel to the opening / closing direction of the molding die, and the turning process is performed on the surfaces of the respective divided cores. A method for producing a molding die, which comprises subjecting the divided cores to an integrated process and then finishing the surface. 2. The method of manufacturing a molding die according to claim 1, wherein the finishing of the surface is to form a surface straddling adjacent split cores. 3. The method for producing a molding die according to claim 1, wherein the processing for finishing the surface is mirror surface processing. 4. The molding die according to claim 1, wherein the turning process performed on the surface of each split core is performed by setting it on a jig that holds the split core at a specific position. Production method. 5. The method of manufacturing a molding die according to claim 4, wherein the jig holds a plurality of split cores at symmetrical positions.