JPS63147835A - Method for centering metallic mold - Google Patents

Abstract

PURPOSE:To enhance the transverse misalignment accuracy and parallelism of a metallic mold consisting of an upper mold and lower mold by forming the plane parts provided to the outside circumferential side faces of the metallic mold flush with the same plane. CONSTITUTION:The plane parts 15a, 15b and 17a, 17b which are the two reference planes for centering are notched and formed simultaneously in the molding of the outside circumferential side faces of the upper mold 15 and the lower mold 17 and a lens forming part. The upper mold 15 and lower mold 17 having the plane parts 15a, 15b and 17a, 17b are imposed on a V-shaped base plate 31 of a mold mounting jig 30 imposed on a stationary surface A. The plane parts 15a, 15b and 17a, 17b of the upper mold 15 and lower mold 17 are positioned in the die clamped state to the V-shaped reference planes 31a, 31b formed on the inside surface of the base plate 31. The circumference of the upper mold 15 and lower mold 17 is gripped by a V-shaped retaining member 32 hinged to one end of the base plate 31 and after the free end 32a thereof is fastened to the other end of the base plate 31 by a lock bolt 33, the molds 15 and 17 are clamped by a tap bolt 34 held at the peak part 32a of the member 32. The plane parts 15a, 15b and 17a, 17b are pressed and fixed to the reference planes 31a, 31b of the base plate 31 by a push bar 35 which is projected when the bolt 34 is tightened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Field of Application) The present invention relates to a method for centering a mold applied to, for example, a press molding device for optical lenses. This invention relates to a mold centering method for improving the precision of molded lenses by reducing lateral misalignment of both upper and lower molds to maintain parallelism.

(Prior Art) In recent years, optical lens molding methods have shifted from polishing processing methods that require complicated steps.

A method of processing by heating and plasticizing a pre-measured glass lump and using a precision press has been attracting attention.

Conventionally, in this type of press molding apparatus for optical lenses, as illustrated in FIG.
are fixed with tie bar nuts 4 via tie bars 3, and a slide plate 5 is installed between the upper and lower fixing plates 1.2.
is provided to be movable in the vertical direction, and the slide plate 5 is pushed upward by a drive device 6 such as a hydraulic cylinder. Some lenses have a structure in which a lens molding material such as raw glass (not shown) is precisely press-molded by mold clamping.

However, in the conventional apparatus described above, during press molding, the slide plate 5 on which the lower mold 8 is supported and fixed is slid on the tie bar 3 to perform mold clamping, so that as shown in FIG. , since a small amount of clearance a is required between the bushing 9 provided on the slide plate 5 and the tie bar 3, when pushing up the slide plate 5 and when aligning the upper and lower molds 7 and 8, be sure to A deviation occurs.

In the case of optical lenses, this amount of deviation is normally required as a permissible limit of about 10 μm in terms of final accuracy, but as mentioned above, in order to allow the slide plate 5 to slide smoothly in the vertical direction, it is necessary to requires a clearance a of 10 to 20 μm, which cannot meet the required accuracy.

Therefore, conventionally, an eighth
A positioning mechanism consisting of a positioning hole 71 and a positioning pin 81 as shown in the figure, or a positioning recess 82 and a positioning protrusion 72 as shown in FIG. Even if there is some misalignment during the ascent, positional accuracy is achieved when the upper and lower molds 7.8 are aligned.

(Problem to be solved by the invention) However, even in this case, there are 8 to 10
A clearance of .mu.m is required, and considering the misalignment error of about 3 to 5 .mu.m due to mold processing and assembly techniques, it is difficult to ensure the above-mentioned required accuracy.

Therefore, the inventors proposed an optical lens press molding device that uses a high-precision guide device with almost no clearance in the moving part of the mold, but in this case, the initial settings of the upper mold and the lower mold are performed accurately. There is a need.

The present invention has been made under the above circumstances, and an object of the present invention is to improve the alignment accuracy and parallelism of the molds when installing the molds in a press molding device, and to achieve high-precision optical performance. An object of the present invention is to provide a method for centering a mold so that a lens can be obtained.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a method for attaching the upper mold and the lower mold to a press molding device. The present invention is characterized in that a flat part is provided on the outer peripheral side of the mold, and the flat parts of the upper mold and the lower mold are aligned in the same plane. By configuring
Since the flat parts provided on the upper mold and the lower mold are aligned in the same plane, it is possible to improve the accuracy of lateral misalignment of the mold, which makes it suitable for press molding equipment for optical lenses. This makes it possible to mold optical lenses with high precision.

(Example) Hereinafter, the present invention will be described in detail with reference to an example shown in FIGS. 1 to 5. In the illustrated embodiment of the present invention, the mold of the optical lens press molding apparatus shown in FIGS. 1 and 2 will be described as an example, but the present invention is not limited thereto.

FIG. 1 schematically shows the overall configuration of an optical lens pressing device to which the present invention is applied.
is erected, and a housing 13 is fixed to the upper part of this support 12, and the internal space of this housing 13 is used as a molding chamber 14. An upper mold 15 is fixed to the upper ceiling surface 14a of the molding chamber 14 via an upper fixing plate 16, while a drive, which will be described later, is installed on the lower bottom surface 14b of the housing 13. A lower mold 17 interlocked with the means 18 is disposed opposite to the upper mold 15 so as to be vertically movable.

That is, the driving means 18 includes a high-rigidity bracket 19 fixed to the lower surface of the housing 13 and having a strength that does not deform at least against mold clamping force;
A hydraulic cylinder 20 assembled to the lower part of the hydraulic cylinder 20, a swivel joint 22 attached to the tip of the cylinder rod 21 of this hydraulic cylinder 20, and a slider 23 assembled into the bracket 19 via this swivel joint 22. Multiple high-precision guide devices 24 that guide you up and down in the vertical direction
As shown in FIG. 2, this high precision guide device 24 includes a guide shaft 25a assembled to the bracket 19.
and the guide shaft 25a is assembled to the slider 23.
Linear motion guide bearing (product name) 25b that has low sliding resistance and engages with high rigidity and positional accuracy.
The slider 23 can be guided up and down in the vertical direction via this high-precision guide device 24, and the slider 23 has an upper end 26a facing the bottom side inside the housing 13. A press shaft 26 is assembled, and the lower die 17 is assembled and fixed to the upper end 26a of the press shaft 26.

According to this press forming apparatus, the press shaft 26 to which the lower mold 17 is attached is assembled to the slider 23 that is slidably guided by a high precision guide device 24 consisting of a guide shaft 25a and a near motion guide bearing 25b. from,
It has low sliding resistance and high rigidity, making it possible to slide and guide the lower mold 17 with a high positional accuracy of 1 to 2 μm.

Furthermore, since the hydraulic cylinder 20 that serves as the driving source for vertical movement is attached to the lower part of the bracket 19 of the driving means 18 that is firmly attached to the housing 13, it is not affected by the reaction force of mold clamping, and the hydraulic cylinder 20 is not affected by the reaction force of mold clamping. Cylinder rod 2 of cylinder 2o
Since a swivel joint 22 is provided at the tip of the cylinder rod 21 and a slider 23 is connected thereto, the cylinder rod 21
lateral displacement has no effect on the slider 23.

Furthermore, since the driving means 18 is designed to be directly attached to the housing 13, the parallelism, centering, etc. when assembling the housing 13 onto the base 11 are better than those of a conventional tie bar set. This makes it much easier to do things □.

In order to mold optical lenses and the like with high precision using such a press molding apparatus, it is necessary to improve the misalignment accuracy of the upper mold 15 and the lower mold 17 at the time of initial setting.

That is, in the present invention, when assembling a mold consisting of an upper mold 15 and a lower mold 17 to the upper fixed plate 16 and the upper end portion 26a of the press shaft 26 of the above-mentioned high-precision press device,
At the same time as forming the lens molding parts on the outer circumferential surfaces of the upper mold 15 and the lower mold 17, as shown in FIG.
A notch is formed so that it has a V-shape.

And such flat parts 15a, 15b and 17a,
The V-shaped base 31 of the mold mounting jig 30 has the upper mold 15 and the lower mold 17 having the upper mold 17b mounted on a suitable fixing surface A.
on V-shaped reference surfaces 31a and 31b formed on the inner surface of this base 31.

The flat parts 15a, 15b and 17a, 17b of the upper mold 15 and lower mold 17 are aligned in a clamped state and left standing (see FIG. 4).

Next, as shown in FIG.
The periphery of the lower mold 17 is held in a non-contact state, and its free end 32a is fastened to the other end of the base 31 with a bolt 33, and then passed through and held by the top 32b of the presser member 32. The two push bolts 34 are tightened while keeping the upper mold 15 and the lower mold 17 in a clamped state, and the upper mold 15 and the lower mold 17 are tightened with each push bolt 35 that protrudes by tightening these push bolts 34. The flat parts 15a, 15 of
b, 17a, 17b are gently pressed against the V-shaped reference surfaces 31a, 31b formed on the inner surface of the base 31 and fixed, the flat parts 15a of the upper mold 15 and the lower mold 17 are fixed.
, 15b and 17a, 17b are aligned in the same plane.

In this state, the upper mold 1 fixed to the mold mounting jig 30 is
5 and the lower mold 17 are first placed on the upper end 26a of the press shaft 26, which is the lower mold mounting surface of the press molding apparatus in the open state, and the lower mold 17 is attached to the press shaft from below with a bolt (not shown). 26 on the upper end 26a. After the lower mold 17 is fixed on the upper end 26a of the press shaft 26, the press molding apparatus is operated to bring the mold into the clamped state, and the upper mold 15 is mounted on the upper mold mounting surface of the press molding apparatus. The upper die 15 is tightly attached to an upper fixing plate 16 and fixed to the upper fixing plate 16 from above with bolts (not shown), after the upper die 15 and the lower die 17 are fixed.

The tightening is performed by loosening the bolts 33 and removing the mold mounting jig 30 from the press molding apparatus. As a result, the misalignment accuracy in the lateral direction of the mold can be greatly improved, and even if various errors during molding due to movement of the press shaft 26 are included, the final misalignment accuracy can be kept at 5 to 8 μm.
In addition, the press molding apparatus for optical lenses can mold optical lenses with high precision.

In the above embodiment, the upper mold 15 and the lower mold 17 have two flat parts 15a and i serving as centering reference surfaces on their outer peripheral surfaces.
Although sb, 17a, and 17b are provided, the present invention is not limited to this, and as long as there is at least one, it is possible to obtain a sufficient centering effect.

It goes without saying that the present invention can be modified in various ways without departing from the gist of the present invention.

[Effects of the Invention] As is clear from the above description, according to the present invention, the flat parts provided on the upper mold and the lower mold are arranged in the same plane. As a result, in press molding equipment for optical lenses, we have developed a mold centering method that has the excellent effect of molding highly accurate optical lenses. It is something that can be provided.

[Brief explanation of the drawing]

The drawings show an example in which an embodiment of the mold centering method according to the present invention is applied to an optical lens press molding device, and FIG. 1 shows an example of a high precision press molding device to which the present invention is applied. A schematic cross-sectional view, Figure 2 is a cross-sectional view of the high-precision press molding equipment section taken along the line ■-■ in Figure 1, and Figure 3 is a mold clamping diagram of the mold mounting jig used in the mold centering method. Figure 4 is an explanatory diagram showing the previous open state, Figure 4 is a cross-sectional view taken along the line IV-IV in Figure 3, Figure 5 is an explanatory diagram showing the mold clamping of the mold mounting jig in the fixed state, and Figure 6 is an explanatory diagram showing the fixed state. The figure is a schematic explanatory diagram of a conventional general optical lens press molding device, FIG. 7 is an enlarged cross-sectional view of the main part of the sliding part between the tie bar and the slide plate, and FIGS. 8 and 9 are FIG. 3 is an enlarged cross-sectional view of a main part showing a positioning mechanism of a conventional mold. 15...Upper mold, 15a, 15b...Plane portion. 17... Lower mold, 17a, 17b... Plane part, 3
0...Mold installation jig. ＼ 31... Base, 31a, 31b.
··Reference plane. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Part 2 Prisoners''■ 2N3 Figure 4 Figure 5 Figure 8 Figure 7 Figure 9

Claims (3)

[Claims] (1) When attaching the upper mold and lower mold to the press molding equipment,
A flat part is provided on the outer peripheral side of the mold consisting of an upper mold and a lower mold,
A mold centering method characterized in that the flat parts of the upper mold and the lower mold are aligned in the same plane. (2) The metal mold according to claim 1, characterized in that the reference surface of the mold mounting jig is pressed against the flat parts of the upper mold and the lower mold so that they coincide within the same plane. How to center the mold. (3) The method according to claim 1 or 2, characterized in that at least two or more flat parts are provided on the outer circumferential side of a mold consisting of an upper mold and a lower mold. How to center a mold.