JPH09187821A - Dach prism molding die and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the molding of a roof prism, at the roof ridgeline of which no mole flashing develops and the roof surface and the roof ridgeline of which are highly accurate. SOLUTION: This roof prism mold 11 has a roof ridgeline molding part 12 and one roof surface molding part 13a and the other roof surface molding part 13b, both of which are arranged at both sides of the roof ridgeline molding part 12 at a predeterined angle and made of one un-divided member. Further, the width of the line of the roof ridgeline molding part 12 is set to be 8μm or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a roof prism used for molding a roof prism by injection molding, compression molding or the like, and a method for producing the same.

[0002]

2. Description of the Related Art As shown in FIG. 1, a roof prism 2 having a roof ridge line 2 and one roof surface 3a on one side and a roof surface 3b on the other side which are arranged at a predetermined angle are injection molded or compression molded. In the case of molding by, a mold for molding a roof prism as described below has been conventionally used.

As shown in FIG. 6 (a), this conventional roof prism molding die forms a roof ridge line for regulating the roof ridge line 2 of the roof prism 1 shown in FIG. 1 and the outer surface of one roof surface 3a. One divided piece mold 101a having one roof surface forming portion 103a divided along the portion 102a
And a roof ridge line forming portion 1 for regulating the roof ridge line 2 of the roof prism 1 and the outer surface of the other roof surface 3b shown in FIG.
The other divided piece mold 101b having the other roof surface forming portion 103b divided along 02b, and the box-shaped frame piece mold 104 as shown in FIG. 6B are provided. As shown, one divided piece die 101a and the other divided piece die 101b are fitted and inserted in the frame piece die 104.

As shown in FIG. 7 (a), the conventional roof prism molding die described above has a movable side die 100.
When the molten resin is injected and filled into the cavity through the sprue 200a after being clamped in combination with the fixed side mold 200, the pressure of the molten resin acts in the direction of the arrow. ) As shown in FIG.
01a and the other divided piece mold 101b are deformed, and a gap S is generated between the contact surfaces of the two. As a result, the molten resin flows into the gap S, and burrs 301 occur on the roof ridgeline of the injection-molded roof prism 300, which in turn increases the line width e of the roof ridgeline. A so-called roof ridge line defect that deteriorates the visibility of the image occurs.

Therefore, in order to prevent such burrs and roof ridgeline defects from occurring, the following roof prism molding dies (a), (b) or (c) have been proposed.

(A) As shown in FIG. 8A, one divided piece mold 111a having one roof surface forming portion 113a in the frame piece mold 114 and the other divided piece mold 111a having the other roof surface forming portion 113b. A die for molding a roof prism that is shrink-fitted with a split piece die 111b.

(B) As shown in FIG. 8B, one divided piece mold 111a having one roof surface forming portion 113a fitted into the frame piece mold 114 and the other roof surface forming portion 1a.
A die for molding a roof prism, which is obtained by tightening the other divided piece mold 111b having 13b with a tightening screw 115 with a predetermined torque.

(C) As shown in FIG. 8 (c), two large and small split piece dies 121a, 121b split on the same plane as one roof surface forming portion 123a are fitted into the frame piece dies 124. A mold for molding a roof prism in which both are tightened with a predetermined torque using a tightening screw 125.

[0009]

However, among the conventional molds for molding the roof prism, (a) and (b) are, as shown in FIG. 9 (a), one divided piece mold 111a and the other divided piece mold 111a. The roof ridgeline forming portion 112 formed with the divided piece mold 111b is deformed by the tightening force from the shape shown by the broken line to the shape shown by the solid line, and both roof surface forming portions 113a, 113b.
Also, the accuracy of the ridge line forming portion 112 deteriorates.

As shown in FIG. 9 (b), (c) is a solid line from the shape of the roof ridge line forming part 122 formed by the two large and small split piece molds 121a, 122b indicated by the broken line by the tightening force. It deforms to the shape shown, and the accuracy of both roof surface forming portions 123a and 123b and ridge forming portion 122 deteriorates.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and does not cause burrs on the roof ridge line of the molded roof prism, and the roof surface and the roof ridge line are highly accurate. An object of the present invention is to realize a die for molding a roof prism capable of molding a simple roof prism and a manufacturing method thereof.

[0012]

In order to achieve the above object, a mold for molding a roof prism of the present invention includes a roof ridge line forming portion and one roof surface forming portion arranged on both sides thereof at a predetermined angle. In a roof prism forming die having the other roof surface forming portion, the roof ridgeline forming portion, the one roof surface forming portion, and the other roof surface forming portion are composed of one member that is not divided. It is characterized by that.

Further, it is preferable that the line width of the roof ridge forming portion is 8 μm or less.

Further, it may be made of pure copper or a copper alloy,
It is preferable that the roof ridgeline forming portion, the one roof surface forming portion, and the other roof surface forming portion are formed of an electroless nickel plating layer.

According to the method for manufacturing a roof prism molding die of the present invention, a ridge line forming portion formed of one member and one roof surface forming portion and the other roof surface forming portion arranged on both sides thereof at a predetermined angle are formed. A method for manufacturing a roof prism molding die having a portion, wherein one undivided member is face-milled with a diamond cutting tool attached to a main shaft to form the ridge line forming portion and the one roof surface forming portion. Is mirror-cut, and then the ridge line forming part and the other roof surface forming part are mirror-cut.

Further, the cutting edge of the diamond bite is attached with its edge offset from the axis of the main shaft,
It is preferable that the radius of curvature of the R surface of the cutting edge is set to 1 μm or less and the straightness of the straight portion of the cutting edge is set to 1 μm or less.

[0017]

Since the roof ridge line forming portion and one roof surface forming portion and the other roof surface forming portion which are arranged on both sides thereof at a predetermined angle are composed of one member which is not divided, At the time of molding, burrs do not occur at the roof ridge line forming portion as in the conventional technique, and it becomes possible to mold the roof prism with high accuracy.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

First, an embodiment of a roof prism molding die according to the present invention will be described.

As shown in FIG. 2A, a roof prism molding die 11 of this embodiment includes a roof ridge line forming portion 12,
It has one roof surface forming portion 13a and the other roof surface forming portion 13b arranged on both sides thereof at a predetermined angle, and is composed of one member which is not divided. The line width a of the roof ridgeline forming portion 12 shown in is 8 μm or less.

Further, the roof prism molding die 11 of the present invention is made of a copper alloy such as pure copper, bronze or brass, and the roof ridge line forming portion, one roof surface forming portion and the other roof surface forming portion are Assuming that the electroless nickel plating layer is used, it is possible to obtain a highly accurate mirror surface and perform injection molding or cutting by performing a cutting process by a face milling method using a diamond cutting tool using a cutting machine such as an NC machine tool. When molding the roof prism by compression molding, it is possible to obtain mechanical strength that can withstand the pressure during molding.

Next, an embodiment of the method for manufacturing the roof prism molding die according to the present invention will be described.

As a cutting machine, as shown in FIG. 3, a main shaft 22 rotated by a rotation driving means (not shown).
A headstock 21 provided with and a work W, which is a single member that is not divided and is disposed so as to face the headstock 21 side of the headstock 21, and can move in each of the X, Y, and Z directions. An NC machine tool that is equipped with a moving table 23 and is capable of mirror-cutting a workpiece W fixed on the moving table 23 via the employment 24 by a diamond tool 25 attached to the spindle 22 via a tool holder 28 by a face milling method is used. .

In this NC machine tool, the movable table 23 can detect the position of each axis X, Y, Z by a laser interferometer and can perform precise positioning of about 0.01 micrometer, and the main shaft 22 can be stationary. It is rotatably supported by the headstock 22 via a pressure bearing, and has a high rotation accuracy of about 0.05 μm.

As shown in FIG. 5, the diamond cutting tool 25 has a diamond tip 27 at the tip of the shank portion 26, and the radius of curvature of the R surface c at the tip of the cutting edge is 1 μm or less, and the cutting edge is The flatness of the effective portion (straight portion) b is 1 micrometer or less, and the angle d of the cutting edge is set to 85 degrees or less.

When attaching the diamond bite 25 to the spindle 22, as shown in FIG. 4, the diamond tip 27 is offset from the axis 0 of the spindle 22, and the angle h between the blade edge effective portion b and the axis O of the spindle 22 is set. 90
Set within the range of 89 to 55 minutes.

This makes it possible to obtain a highly accurate mirror surface in which no rainbow is generated.

When the angle h between the effective portion b of the cutting edge and the axis O of the main shaft 22 deviates from the range of 90 degrees to 89 degrees 55 minutes, a saw-toothed concavo-convex pattern of about 0.05 micrometer even if it appears to be a mirror surface. Is formed and a rainbow is generated.

On the other hand, the work W is moved to the moving table 2 via the hire 24.
The machined surface is fixed on the upper surface of the diamond cutting tool 25 so that the processed surface thereof is parallel to the effective cutting edge portion b of the diamond tip 27.

After the above, the diamond bit 25 is rotated together with the spindle 22 to move the work W to the moving table 23.
One roof surface forming portion 13 is formed by performing a mirror cutting process by a so-called front milling method that is moved together.
a and the roof ridge line forming portion 12 are formed.

After the above, the work W is moved to the moving table 23.
The Dach prism forming die 11 is manufactured by rotating the above 180 degrees and fixing it through the employment 24, and forming the other roof surface forming portion 13b and the roof ridge forming portion 12 by the same process as above.

The present invention can be applied to all prisms having a roof surface such as a penta roof prism.

[0033]

Since the present invention is configured as described above, it has the following effects.

Since the die for molding the roof prism is composed of one member which is not divided, burrs do not occur on the roof ridgeline of the molded roof prism, and the roof prism can be molded with high accuracy.

Further, unlike the above-mentioned conventional technique, it is not necessary to prepare the divided piece mold and the frame piece mold and assemble them, so that the manufacturing cost is greatly reduced.

Further, it has a mechanical strength capable of withstanding the pressure at the time of molding the roof prism by injection molding or compression molding.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of a roof prism.

2A and 2B show an embodiment of a mold for molding a roof prism according to the present invention, wherein FIG. 2A is a schematic perspective view and FIG. 2B is a circle A of FIG.
It is a model partial side view of the part enclosed with.

FIG. 3 is an explanatory view showing one step of a method for manufacturing a roof prism molding die according to the present invention.

FIG. 4 is an explanatory view showing a setting state of a diamond tool in the method for manufacturing a roof prism molding die according to the present invention.

5A and 5B show a diamond bite used for manufacturing a die for molding a roof prism of the present invention, wherein FIG. 5A is a front view and FIG.
Is a side view, and (c) is a schematic partial enlarged view of a portion surrounded by a circle A in (a).

FIG. 6 shows an example of a conventional roof prism molding die,
(A) is a schematic perspective view of a pair of disassembled split pieces,
(B) is a schematic perspective view of the disassembled frame piece mold, and (c) is a schematic perspective view of a roof prism molding die in which a pair of split piece molds are fitted in the frame piece mold.

FIG. 7 is an explanatory diagram showing a burr generation principle during injection molding using the roof prism molding die shown in FIG. 6;

FIG. 8 is a schematic cross-sectional view showing another example of a conventional roof prism molding die.

9 is a schematic enlarged partial cross-sectional view of a portion surrounded by a circle in each of the roof prism molding dies shown in FIG.

[Explanation of symbols]

 1 roof prism 2 roof ridge line 3a one roof surface 3b other roof surface 11 roof prism molding die 12 roof ridge forming portion 13a one roof surface forming portion 13b other roof surface forming portion 21 spindle base 22 spindle 23 moving base 24 hiring 25 Diamond Tool 26 Shank Part 27 Diamond Tip 28 Tool Holder

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location // B29L 11:00

Claims (6)

[Claims] 1. A roof prism forming die having a roof ridge line forming portion and one roof surface forming portion and the other roof surface forming portion arranged on both sides thereof at a predetermined angle, wherein the roof ridge line forming portion, A roof prism molding die, wherein one roof surface forming portion and the other roof surface forming portion are composed of one member which is not divided. 2. The mold for molding a roof prism according to claim 1, wherein the line width of the roof ridge forming portion is 8 μm or less. 3. The mold for molding a roof prism according to claim 1, which is made of pure copper or a copper alloy. 4. The metal for forming a roof prism according to claim 1, wherein the roof ridge line forming portion, one roof surface forming portion and the other roof surface forming portion are formed of an electroless nickel plating layer. Type. 5. A method for manufacturing a roof prism forming die having a ridge line forming portion formed of one member, and one roof surface forming portion and the other roof surface forming portion arranged on both sides thereof at a predetermined angle. The ridge line forming portion and the one roof surface forming portion are mirror-finished by a front milling method using a diamond bite attached to a main shaft, and then the ridge line forming portion is formed. And a method for manufacturing a roof prism molding die, wherein the other roof surface forming portion is mirror-cut. 6. The diamond bite is mounted such that its cutting edge is offset from the axis of the main shaft, the radius of curvature of the R surface of the cutting edge is 1 micrometer or less, and the straightness of the straight part of the cutting edge is 1 micron. The method for manufacturing a roof prism molding die according to claim 5, wherein the die is set to be equal to or less than a meter.