JPH04170333A - Structure of press forming die - Google Patents

Abstract

PURPOSE:To improve the thickness accuracy and surface condition of formed goods and further the life of the forming die having an upper die and a lower die sliding within a sleeve by providing notched parts forming gasp with the upper die in a butt state at annular band-shaped top end of the sleeve. CONSTITUTION:The three notched parts 10a to 10c are formed at the annular bans-shaped top end of the sleeve 6 and non-notched parts 12a to 12c at the annular band-shaped top end are provided. The annular band-shaped top of the outer periphery of the forming surface of the upper die 4 is abutted against the respective non-notched parts 12 at the top end of the sleeve 6 and the thickness of the formed goods is set at the time of pressing. The evaporating component generated from a blank material G for forming by the high temp. at the time of the pressing is escaped from the gaps between the respective notched parts 10 at the top end of the sleeve 6 and the annular band-shaped top edge on the outer periphery of the forming surface of the upper die 4 to the outside of the die. Them the surface condition of the formed goods and the die is well maintained even after the repetitive forming and the life of the die is prolonged.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to the structure of a press molding die, particularly for press forming to maintain good thickness accuracy and surface condition of a molded product and to maintain a long mold life. Concerning the structure of types. The present invention can be suitably applied, for example, to a mold for rapidly manufacturing an optical element having an optically functional surface from a molding material by pressing.

[Problems to be solved by conventional techniques and inventions] In recent years,
A material for forming an optical element, such as a glass blank preformed to a certain degree of shape and surface accuracy, is placed in a mold with a predetermined surface accuracy and press-molded under heat, after grinding and polishing. A method for manufacturing an optical element having a high-precision optical function surface that does not require processing has been developed.

In this press molding method, a pair of mold members are arranged so as to be able to move relatively back and forth in opposite directions, and molding is performed in a cavity formed by a member including at least the pair of mold members. A molding material is introduced, and the atmosphere is set to a non-oxidizing atmosphere, such as a nitrogen atmosphere, to prevent the mold member from drying, and the molding material is heated to a moldable temperature of 10" to 1012".
The mold member is heated to a temperature that causes poise, the mold is closed and pressed for an appropriate time to transfer the surface shape of the mold member to the surface of the molding material, and the temperature of the mold member is lowered to a temperature sufficiently lower than the glass transition temperature of the molding material. Cool, remove the press pressure, and open the mold to remove the molded optical element.

According to the press molding method as described above, aspherical lenses and the like, which were conventionally extremely expensive, can be manufactured at relatively low cost.

By the way, in the above mold for pressing, the wall thickness of the molded product (i.e., the thickness in the direction corresponding to the opposing direction of the upper mold member and the lower mold member, which are a pair of mold members for upper molding) is It is set by the movement stop position when moving the upper die member and the lower die member relative to each other for pressing. Conventionally, in order to set the stop position, an annular edge on the outer periphery of the transfer molding surface of the upper mold member (a spherical or planar edge common to the transfer molding surface of the upper mold member) is attached to the sleeve-shaped body. Ring-shaped upper end of the mold member (spherical or flat upper end corresponding to the transfer molding surface of the upper mold member)
(For example, Japanese Patent Application Laid-Open No. 60-1999)
5i623).

However, in the above-mentioned conventional example, since the pressing ends with the annular upper end of the old mold member and the annular edge of the upper mold member abutting each other and the mold cavity is sealed, this occurs due to heating of the molding material. Evaporated components (lead, alkali, etc.) are trapped inside the cavity and adhere to the surfaces of molded products and mold members. As a result, the surface condition of the molded article may deteriorate (for example, a decrease in transparency), the surface condition of the mold member may deteriorate, and the surface condition of the molded article may also deteriorate after repeated molding.

Therefore, in view of the problems of the prior art as described above, the present invention always accurately sets the stop position of the relative movement between the upper mold member and the lower mold member during pressing, and improves the thickness accuracy of the molded product. We have created a structure for a press mold that allows evaporated components from the molding material to escape outside the mold cavity while maintaining a good surface condition to obtain a molded product with a good surface condition and further maintain a long mold life. The purpose is to provide

[Means for Solving the Problems] According to the present invention, the above object is achieved by comprising an upper mold member, a lower mold member, and a sleeve, the lower mold member being longitudinally disposed within the sleeve. In the structure of the press molding mold which is slidably arranged, a part of the annular upper end of the sleeve abuts against a spherical or planar annular edge common to the transfer molding surface of the upper mold member. The other part of the upper end of the sleeve is a notch that forms a gap with the annular edge of the upper mold member in the abutted state. , a structure of a press molding mold, are provided.

In the present invention, the circumferential rotation of the lower die member relative to the sleeve in the longitudinal direction of the sleeve is locked, and the sleeve has a plurality of cutouts equally spaced in the circumferential direction, and the upper die member There is an embodiment in which the annular edge of the member is provided with a protrusion that engages with one of the plurality of notches in the sleeve.

Further, according to the present invention, the above object is achieved by comprising an upper mold member, a lower mold member, and a sleeve, and the lower mold member is arranged to be slidable in the longitudinal direction within the sleeve. In the structure of the press molding mold, a part of the spherical or planar ring-shaped edge common to the transfer molding surface of the upper mold member is brought into contact with the ring-shaped upper end of the sleeve. , the other part of the annular edge of the upper mold member is a notch that forms a gap with the upper end of the sleeve in the abutting state. , is provided.

In the present invention, circumferential rotation of the lower die member relative to the sleeve in the longitudinal direction of the sleeve is locked, and the upper die member has a plurality of notches equally provided in the circumferential direction, and There is an embodiment in which the upper end of the sleeve is provided with a protrusion that engages with one of the plurality of notches of the upper die member.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. In addition, the following examples are those applied to press molding of optical lenses.

FIG. 1 is a longitudinal sectional view showing a first embodiment of the structure of a press molding die according to the present invention, and FIG. 2 is a front view thereof. Note that FIG. 1 corresponds to the II cross section in FIG. 2.

In these figures, reference numeral 2 denotes a lower mold member, the upper surface of which is a molding surface finished to the required surface precision for transfer-forming the first optically functional surface of the lens. This molding surface may have an aspherical shape.

Reference numeral 4 denotes an upper mold member, the lower surface of which is a molding surface finished to the required surface precision for transfer-forming the second optically functional surface of the lens. This molding surface is spherical or planar. These two mold members 2.4 constitute a pair of mold members.

6 is a sleeve, which allows the lower die member 2 to be
is supported so as to be movable in the vertical direction.

A support plate 8 is fixed to the lower part of the sleeve 6. The lower mold member 2 is restricted from moving downward by the support plate 8.

The lower part of the bottle 7 attached to the sleeve 6 engages with a vertical groove formed on the side surface of the lower mold member 2,
In this way, the lower die member 2 is prevented from rotating relative to the sleeve 6 in the longitudinal direction of the sleeve.

G is a molding material.

FIG. 3 is a perspective view of this embodiment in which the upper mold member 4 and the molding material G are not shown.

The annular upper end of the sleeve 6 has three notches lOa, 1
0b and 10c are formed. And 12a, 12
b, 12c are non-cut portions of the annular upper end portion, the upper end surface of which has a shape corresponding to the molding surface of the upper mold member 4, and the annular edge of the outer periphery of the molding surface of the upper mold member 4 during pressing. It looks like it's being pushed against the body. The above cutout portions 10a, 1
0b, 10c and the non-cut portions 12a, 12b, 12c have equal circumferential lengths.

FIG. 4 is a perspective view showing the upper die member 4 of this embodiment.

A sleeve 6 is attached to the annular edge of the outer periphery of the molding surface of the upper mold member 4.
A protrusion 5 having a circumferential length corresponding to the notch at the upper end is provided.

In this embodiment, as described above, when pressing, the first
As shown in the figure, the annular edge on the outer periphery of the molding surface of the upper die member 4 is the non-cut portion 12a, 12b of the upper end of the sleeve 6.
, 12c to set the thickness of the molded product.

The evaporated components generated from the molding material G due to the high temperature during pressing are removed from the notches 10a and 1 at the upper end of the sleeve 6.
0b, 10c and the annular edge on the outer periphery of the molding surface of the upper mold member 4 to escape out of the mold, so even after repeated molding, the surface condition of the molded product and mold member is maintained in good condition.
The life of the mold parts is also increased.

Incidentally, the protrusion 5 provided on the upper die member 4 is connected to the sleeve 6.
The upper die member 4 is engaged with one of the three notches 10a, 10b, and loc (10a in FIGS. 1 and 2) at the upper end, and the upper mold member 4 is thus moved relative to the sleeve 6 in the longitudinal direction of the sleeve. It is designed so that it does not rotate around. However, this engagement does not close the gap. This selection of engagement is determined by testing the combinations of the three cutouts 10a, fob, and 10c in advance, and checking the optical performance of the molded product (particularly, the possibility of one-sided blurring due to uneven thickness of the lens edge). ) and select the combination that provides the best optical performance.

Furthermore, in this embodiment, the lower mold member 2 is movable in the vertical direction relative to the sleeve 6, so even if the molded product shrinks during the cooling process after pressing, the lower mold member 2 will follow the movement. Therefore, the surface accuracy of the molded product can be improved.

FIG. 5 is a longitudinal sectional view showing a second embodiment of the structure of a press molding die according to the present invention, and FIG. 6 is a front view thereof. Incidentally, FIG. 5 corresponds to the cross section taken along the line ■-■ in FIG. 6. In these figures, the same members as in FIGS. 1 to 4 are given the same reference numerals. FIG. 7 is a perspective view showing the upper die member 4 of this embodiment, and FIG. 8 is a perspective view of this embodiment in which illustration of the upper die member 4 and the molding material G is omitted.

In this embodiment, three notches 14a, 14b, and 14c are formed on the annular edge of the outer periphery of the molding surface of the upper mold member 4. Reference numerals 16a, 16b, and 16c are non-cut portions of the annular edge, which are brought into contact with the annular upper end of the sleeve 6 during pressing. The cutout portion 14a,
14b, 14C and non-cut portions 16a, 16b, 16c have equal circumferential lengths.

A protrusion 9 having a circumferential length corresponding to a notch in the annular edge of the outer periphery of the molding surface of the upper die member 4 is provided at the annular upper end of the sleeve 6 .

This embodiment corresponds to the first embodiment in which the functions of the annular edge on the outer periphery of the molding surface of the upper mold member 4 and the upper end of the sleeve 6 are reversed, and the effect is the same as that of the first embodiment. This is equivalent to the embodiment.

[Effects of the Invention] As explained above, according to the structure of the press molding die of the present invention, there is a notch in one of the annular upper end of the old mold member and the annular edge of the outer periphery of the molding surface of the upper mold member. Since a gap is formed when the upper mold member is butted against the sleeve, the thickness of the molded product can be set accurately, and the evaporated components generated from the molding material due to the high temperature during pressing can be prevented. escapes out of the mold through the gap, and even after repeated molding, the surface condition of the molded product and mold member is maintained in good condition, and the life of the mold member is extended.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a first embodiment of the structure of a press molding die according to the present invention, and FIG. 2 is a front view thereof. FIG. 3 is a perspective view of this embodiment, with illustrations of the upper mold member and the molding material omitted, and FIG. 4 is a perspective view showing the upper mold member of this embodiment. FIG. 5 is a longitudinal sectional view showing a second embodiment of the structure of a press molding die according to the present invention, and FIG. 6 is a front view thereof. FIG. 7 is a perspective view showing the upper die member of this embodiment, and FIG. 8 is a perspective view of this embodiment in which illustration of the upper die member and the molding material is omitted. 2: Lower mold member, 4: Upper mold member, 5.9: Protrusion, 6: Sleeve, 7: Bottle,
8: support plate, 10a to 10c notch at upper end of varnish rib, 12a to 12c non-cutting portion at upper end of varnish rib, 14a to 14c: notch at ring-shaped edge of outer periphery of molding surface of upper mold member, 16a ~16c: Non-cut portion of the annular edge on the outer periphery of the molding surface of the upper mold member, G: Molding material. Agent Patent Attorney Tsuki Yamashita Half cylinder 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6■

Claims (4)

[Claims] (1) In the structure of a press molding mold having an upper mold member, a lower mold member, and a sleeve, the lower mold member is arranged slidably in the longitudinal direction within the sleeve, a ring of the sleeve. A part of the upper end of the sleeve is configured to abut against a spherical or planar annular edge that is common to the transfer molding surface of the upper mold member, and the other part of the upper end of the sleeve is abutted against the abutment. A structure of a press molding mold, characterized in that the cutout portion forms a gap between the upper mold member and the annular edge portion in the above-mentioned state. (2) Circumferential rotation of the lower mold member relative to the sleeve in the longitudinal direction of the sleeve is locked, and the sleeve has a plurality of cutouts equally provided in the circumferential direction, and the upper mold member ring 2. The structure of the press molding die according to claim 1, wherein the band edge is provided with a protrusion that engages with one of the plurality of notches of the sleeve. (3) In the structure of a press molding mold having an upper mold member, a lower mold member, and a sleeve, the lower mold member is disposed so as to be slidable in the longitudinal direction within the sleeve, the upper mold member A part of the spherical or planar ring-shaped edge common to the transfer molding surface of the sleeve is abutted against the ring-shaped upper end of the sleeve, and the other part of the ring-shaped edge of the upper mold member The structure of the press molding die is characterized in that the notch portion forms a gap with the upper end portion of the sleeve in the abutting state. (4) Circumferential rotation of the lower mold member relative to the sleeve in the longitudinal direction of the sleeve is locked, and the upper mold member has a plurality of notches equally spaced in the circumferential direction, and the upper end of the sleeve 4. The structure of a press molding mold according to claim 3, wherein the part is provided with a protrusion that engages with one of the plurality of notches of the upper mold member.