JPH01257141A - Press forming method for optical parts - Google Patents

Abstract

PURPOSE:To prevent the generation of burrs by using a glass stock having the volume slightly larger than the volume of a glass forming and ending the press forming in the non-filled state to avert the deformation of the glass forming before the softened glass comes into contact with the inside wall of a barrel die at the time of pressing the glass stock by using the barrel die, a punch and a die. CONSTITUTION:The press die consisting of the barrel die, the punch 6 to be slidably fitted into the die 1 and the die 5 is prepd. The glass stock 2 having the slight excess component than the volume of the glass forming is heated to the softening temp. necessary for forming or above and is supplied into the die 5. The punch 6 is then lowered down to the prescribed strike just before the point where the punch comes into contact with the die 5. The press forming of the glass forming is ended in the state where the excess material does not come into contact with the inside wall of the die 1. The punch 6 is held in this position until the temp. of the softened glass 2 falls down to the glass transition point temp. or below, by which the press forming having no burrs is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a press molding method for optical parts, and in particular, press molding of glass material gold softened by heating, as in the case of molding precision optical parts. This invention relates to improvements in press molding methods.

C. Conventional technology] Conventionally, when press forming a pressed product from a glass material,
For example, as shown in Japanese Unexamined Patent Publication No. 59-12369, shaped glass is supplied into the lower mold into a mold formed in advance by an upper mold, a lower mold, and a body mold, and molded glass is molded until it is completely filled. The method used was to lower the soil mold and pressurize it.

[Problem to be solved by the invention]

As mentioned above, in the conventional press molding method of optical parts,
In the following points, there is still room for a few more steps. The glass material gets stuck in the gaps between the upper and lower molds and the body mold, solidifies into the finished product, and tends to cause flakes when taken out, requiring deburring work to remove the flakes. However, when taking out the molded product, the mold broke and entered the lower mold, leaving a residue in the lower mold, making it necessary to interrupt the rounding operation, which hindered continuous work. Furthermore, if this slag enters the gap between the body mold and the lower mold, galling may occur during sliding of the lower mold, which may cause damage to the mold.

(2) In the case of the conventional complete filling method, the dimensions of the molded product are determined by the volume of the material, so it is necessary to completely fill the material into the tube by weight, and careful attention must be paid.

The present invention has been proposed in order to address the above points, and its purpose is to produce hot press-formed products such as optical components with high density without damaging their shape or K. The object is to provide a press molding method that allows continuous press molding.

[Means for fully determining the issue]

In order to solve the above-mentioned problems, the invention of the press-molding method for optical components of the present invention involves heating a glass material to a temperature higher than the softening temperature required for molding, and molding the heated softened glass into a body mold and the body. A glass molded product is pressed by feeding the glass mold into the lower mold of a press mold consisting of an upper mold and a lower mold which are slidably inserted into the mold, and lowering the upper mold to pressurize the softened glass. In the press-molding method for nine-dimensional parts, the glass material is made into a glass material that has a slightly surplus volume compared to the volume of the glass molded product, and the upper mold is lowered to a predetermined stroke before contacting the lower mold. By doing so, the press forming of the glass molded product is completed without the excess material coming into contact with the inner wall of the body mold, and the upper mk is held in that position until the temperature of the softened glass falls below the glass transition temperature. It comes out.

[Effect]

In conventional press molding methods, softened glass is pressurized until it is completely filled in the void formed by the upper mold, lower mold, and body mold. The softened material is crowded in the crevice, and it is taken out as a finished product at 9:00 K.
However, since particles often adhere to the finished product, it is necessary to remove the particles from the finished product, making continuous molding impossible, and the particles can also cause damage to the mold. The ninth way to prevent the above is to strictly fill the material with g! In addition to forming the entire gap, the press surface of the lower die is machined into a stepped shape, and the outer diameter of the stepped portion is made equal to the outer diameter of the finished press product. The press forming is finished before the glass material deforms until it comes into contact with the wall surface of the barrel mold during extrusion 710, that is, just before the void is completely filled with the softened glass. This state is maintained until the temperature of the press-formed product falls below the transition temperature w of the material (the temperature at which it cools from a liquid and turns into a solid). By this, it is possible to prevent the occurrence of cracks in the press-formed product and also to prevent deterioration in the accuracy of the finished product.

〔Example〕

An exemplary embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 1 is a vertical cross-sectional view showing the overall #4 configuration of the mold used in the press molding method according to the present example, FIG. 2 is a vertical cross-sectional view of the body mold in FIG. 1, and FIG. Fig. 2 is a side fgr side view of the barrel mold, Fig. 4 is the IV-IV Senmachi plane of Fig. 2, and Fig. 5 is a longitudinal section of the metal mold in Fig. 1 showing the pressurized state of the material. FIG. 6 is a vertical cross section of the mold showing the molded product removed state in the first factor.

First, an overview of the press forming method of the present invention will be explained using FIG. 1 and FIG. Glass 2, lllll11] type 1, this body m1
By feeding the softened glass 2 into the lower fJ and 5 of the press mold consisting of an upper mold 6 and a lower mold 5 which are slidably fitted into the inside, and lowering the upper mold 6t to pressurize the softened glass 2, When press-molding the glass molded product 7, the glass material is
The glass material has a slight surplus over the volume of the glass molded product 7, and is lowered to a predetermined stroke before coming into contact with the upper die 6 and the lower die 5, so that the excess material comes into contact with the inner wall of the body die 1. The upper mold 6 is held in that position until the press molding of the glass molded product 7 is completed without any problems, and the temperature of the softened glass 2 falls below the glass transition point @L degrees.

Regarding the configuration of the pot mold used in the press molding method of the present invention,
This will be explained in detail using FIGS. 1 to 6.

1 is an inward-facing body type, and on the side of this body type 1,
A rectangular softened material supply port 1α and a press-molded product outlet 1b opposite thereto are provided.

This press molded product outlet 1b (same shape as the softened material supply port 1α) has a diameter larger than the inner diameter of the body mold 1 in order to enable the molded product to be taken out from the lower mold 5, which will be described later. There is. 1. This body mold 1 is fixed to a mold holder 11 by bolts 12 inserted into mounting holes 10 (FIG. 4).

6 is attached to the ram (not shown) of the press, and the body mold 1
Upper mold that can slide vertically inside, 5tl'i
This is a lower die that can slide vertically within the body die 1 and has an embossing rod 5α that passes through the through hole 1C of the body die 1 and is connected to a hydraulic press (not shown). . Above,
The press surface of both the lower molds is processed into a stepped shape.
The outer diameter of the stepped portion is the same as the outer diameter of the press-formed product.

No. 2 is a specific softening glass that is heated to a softening temperature higher than that required for molding. 3 is a shade disposed horizontally facing the softened material supply port 1α of the body m1; 4 is a material supplying device for rolling the entire softened glass 2 on the shade 3 and feeding it into the lower mold 5; 8, This is a molded product retrieval device that is horizontally reciprocably disposed at the press molded product retrieval port 1b9tl, is connected to a Makabe pump (not shown), and has seven suction parts 8α.

9 is a heating furnace capable of heating the upper mold 6 and the lower mold 5 to a predetermined temperature necessary for molding the material.

Next, a method for press-molding an optical component according to an embodiment of the present invention will be described using the press-molding die configured as described above.

When the upper mold 6 and the lower mold 5 are preheated to a predetermined temperature in a heating furnace 9, the softened glass 2 heated and softened in a material heating furnace (not shown y) advances in the direction of the arrow on the shade 6. While being pushed and rolled by the material supply device vt4, it falls from the softened material supply port 1α of the body mold 1 and is supplied into the lower mold 5. After that, the material supply device i4 retreats. 6 slides inside the body mold 1 and descends by a predetermined amount corresponding to the thickness of the molded product, the softened glass 2 is pressurized by the upper mold 6 and the lower mold 5, and the mold is closed (at this time (The upper mold 6 does not come into contact with the lower mold 5), and the glass molded product 7 is molded in the upper and lower molds (Fig. 5).In this state, the heating furnace 9
At the same time as the 1W is turned off, the cooling device (not shown) is operated to cool the mold until the temperature of the molded product falls below the transition point temperature that does not impair the shape and accuracy of the molded product. Hold.

When the temperature of the molded product falls below a predetermined temperature and mold cooling is completed, the upper mold 6 is raised to a predetermined position above the press-molded product outlet 1b by the front six pillars, and then the molded product take-out device 8 is activated. Move forward in the direction of the arrow (Fig. 5) and press the suction part 8α.
It stops when it is above the lower mold 5. Glass molded product 7
The lower die 5 is pushed up by the hydraulic press via the embossing rod 5α to a position where it lightly contacts the suction part 8α (
Figure 6]. Here, when the Makabe pump is activated and the glass molded product 7 is sucked into the suction part 8α, the lower mold 5 is lowered and the glass molded product 7 is molded from the lower mold 5. When the molded product take-out device i[8 is moved back and the glass molded product 7 is transferred to a molded product storage area (not shown), the true pump is stopped and gas is again introduced into the suction part 8α, Glass molded products are stored in the molded product storage area. At the same time as the lower mold completes its descent, the upper mold 6 and the lower mold 5 are again heated to a predetermined molding temperature by the 7111 heating furnace 9. Thereafter, this operation is repeated to obtain a predetermined number of desired glass molded products.

The effects of the non-execution example are as follows: +1) The press molding is completed in a non-light state in which the softened glass does not deform until it comes into contact with the inner wall of the body mold, so no burrs occur on the molded product, and the work to remove burr from the molded product is also easy. No longer needed.

(2) Since no paris is generated and no paris remains in the lower mold, the inner wall of the body mold will not be rubbed and damaged when the lower mold is pushed up to take out the glass molded product.

(3) Since the mold does not enter the gap between the lower mold and the working mold, the mold will not be damaged.

(4) The upper and lower molds are assembled into the body mold, and the outer diameter of the pressed stepped part of the upper and lower molds is set to the same size as the outer diameter of the glass molded product, Glass molded products with good concentricity and no misalignment can be obtained.

In addition, a book! A! In the example, we will explain the case of press-molding optical parts using glass materials, but we will also explain that press-molding can be performed in the same way as in the case of glass materials when plastic materials are used. The effect is also similar.

〔Effect of the invention〕

As explained in detail above, the press molding method for optical components of the present invention provides the following effects.

(1) It is possible to obtain a press-formed product free of flakes without damaging the shape, fPt, or the like, which is effective in terms of productivity.

(2) In addition to not causing any cracks, the process from raw material to molded product construction can be performed without interruption, and delayed growth is possible.

(3) Since there is no occurrence of molding, the defect rate of molded products is reduced, and there is no need to worry about maintenance, inspection, or replacement of molds, labor costs and material costs can be reduced, and production costs can be reduced. It is effective in improving the filling efficiency.

In summary, it is possible to provide a press molding method that can continuously press mold hot press molded products such as precision optical components without impairing their shape and degree of grain.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the overall structure of the mold used in the press molding method according to the present example, FIG. 2 is a vertical cross-sectional view of the mold in FIG. 1, and FIG. 4 is a side sectional view of the mold in FIG. 2, FIG. 5 is a vertical sectional view of the mold showing the pressurized state of the material in FIG. The diagram is. FIG. 2 is a longitudinal sectional view of the mold in FIG. 1 showing a state in which the molded product is taken out. FI with ku code! ll light> 1...Mold, 1a...Softening material supply port, 1b mountain press molded product ball outlet, 1C...X outlet, 2...Glass material, 5...Chute, 4. ...Leaf material supply device, 5...
・Lower mold, 6... Upper mold, 7... Glass molded product, 8...
- Molded product removal device, 8α... Suction part, 9... Heating furnace, 10... Mounting hole, 11... Mold pedestal, 12...
bolt. /l-29,, old/2-1 η；゛/mut

Claims (1)

[Claims] 1. A glass material is heated to a softening temperature higher than that required for molding, and the heated softened glass is formed into a press mold consisting of a body mold, and an upper mold and a lower mold that are slidably fitted into the body mold. In a press-molding method for an optical component, the glass molded product is press-molded by supplying the softened glass into the lower mold of a mold and lowering the upper mold to pressurize the softened glass.
The glass material has a slight surplus compared to the volume of the glass molded product, and by lowering the upper mold to a predetermined stroke before contacting the lower mold, the excess material comes into contact with the inner wall of the body mold. 1. A method for press-molding an optical component, characterized in that press-molding of a glass molded article is completed without any interruption, and the upper die is held in that position until the temperature of the softened glass falls below the glass transition temperature.