KR101831844B1 - An method for manufacturing curved glass - Google Patents

Abstract

Disclosed is a method for manufacturing curved glass, which comprises the following steps: a first step of directly heating a glass material to be processed to the temperature above the softening temperature; a second step of preheating a molding die to be formed into the glass material to the temperature equal to or lower than the softening temperature; a third step of mounting the glass material heated in the first step on a preformed molding die in the second step and slowly cooling the glass material while molding the glass material in a desired shape; and a fourth step of cooling the glass material subjected to the third step to the temperature equal to or lower than the strain point. An object of the present invention is to provide an improved method for manufacturing the curved glass, which can simplify the process while reducing costs and improving productivity.

Description

TECHNICAL FIELD [0001] The present invention relates to a curved glass manufacturing method,

The present invention relates to a curved glass manufacturing method, and more particularly, to a curved glass manufacturing method for producing a curved glass by molding a cover glass of a portable electronic device into a curved surface.

Mobile phones such as smart phones and tablet PCs are equipped with window glass on the front.

Such a window glass has been conventionally provided in the form of a flat plate. Recently, however, a window glass having a curved surface portion has been provided to more closely contact the user's face at the time of a call, and the adoption thereof is gradually increasing.

In the case of such a curved glass, a glass formed in a streamlined shape in the left and right direction is used. In recent years, as shown in Fig. 1, a curved glass whose central portion is a flat plate- This trend is gradually increasing.

Thus, in order to form a so-called 3D curved glass having curved surfaces on both sides, conventionally, the surface of the work has been cut into a curved surface using a cutting machine. In this case, however, the processing time is long, and the processed surface of the glass is rough and the quality is deteriorated.

In view of this, recently, a method of forming a curved glass by heating and cooling a flat plate glass material by using a mold equipment has been used.

As an example, Korean Patent Registration No. 10-1121449 discloses an apparatus for producing a curved glass using a mold. According to the above conventional curved glass manufacturing apparatus, the material is gradually preheated through a plurality of stages using so-called preheating means (preheating lower and upper heaters) provided in the preheating chamber, heating the preheated material in a plurality of stages to a high temperature The curved surface is processed by heating and molding by a plurality of steps using the molding means (heated upper and lower molds), and the curved surface is cooled step by step using the cold water end and cooling means to raise the curved glass .

However, according to the above-described conventional curved glass forming method, since the mold itself is molded while heating to maintain the high temperature required for molding, it takes a long time to heat and cool the mold at a high temperature. In other words, since the mold itself is heated, it is not possible to use a metallic mold in consideration of the releasing property between the molded material and the mold at a high temperature. Therefore, it is necessary to use a graphite mold which takes a long time for heating and cooling , The above-described problems occur.

In addition, since the mold itself must be heated to a high temperature, the durability of the mold itself is weakened and it is limited to use for a long time. Therefore, it is necessary to periodically replace and control the mold, thereby increasing cost and decreasing productivity.

Further, since the preheating means for preheating in a plurality of stages, the molding means for heating and molding in a plurality of stages, and the cold water stage and the cooling means must be provided for each process, the overall molding equipment becomes large and complicated, And the maintenance cost is increased. In addition, since the machining process is complicated and takes a long time, the number of maintenance points (stepwise preheating temperature, stepwise heating temperature, steaming temperature, cooling temperature, etc.) .

Korean Patent No. 10-1121449

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide an improved method of manufacturing a curved glass which can simplify the process and reduce the cost and improve the productivity.

According to another aspect of the present invention, there is provided a method of manufacturing a curved glass, comprising the steps of: directly heating a glass material to be processed at a temperature higher than a softening point; A second step of preheating the molding die to be molded with the glass material to a temperature equal to or lower than the softening point temperature; A third step of mounting the glass material heated in the first step on a preformed molding die in the second step and slowly cooling the glass material while forming the desired shape; And cooling the glass material having undergone the third step to a temperature equal to or lower than a strain point.

Thus, the curved glass processing step can be simplified and shortened.

Here, the forming die is preferably formed of a metal material.

As a result, it is possible to improve the flatness of the object to be processed, that is, the glass material, to prevent contamination of the glass material, and to shorten the heating and cooling time of the molding die.

Further, in the third step, it is preferable that the formed glass material is slowly cooled to a temperature equal to or lower than the strain point.

Thus, it is possible to prevent the deformation of the curved glass when the molded glass is moved to the cooling position by simultaneously performing the molding and gradual cooling steps.

It is also preferable that the first step and the second step are performed simultaneously.

Thus, the machining time can be shortened.

Heating the glass material heated to a temperature equal to or higher than the softening point in the first step to a temperature higher than the softening point temperature of the portion of the pick-up unit that conveys the glass material, .

Thereby, the temperature of the glass material is prevented from being lowered during the movement to the forming position, so that the molding process can be effectively performed.

According to the curved glass manufacturing method of the present invention, when the glass material to be curved is heated in advance to the softening point temperature or higher,

The molding and slow cooling steps can be performed simultaneously.

At this time, since it is not necessary to heat the molding die at a high temperature, the life of the mold can be extended and a temperature difference with the heated glass material is generated, so that the releasability can be improved. Therefore, the problem of the releasability can be solved and the metal mold can be used, so that the flatness can be improved and contamination of the object to be processed can be prevented.

Further, since the metal mold is used, the heating time and the cooling time of the metal mold can be shortened, and the process time can be shortened.

This makes it possible to miniaturize and simplify the entire machining equipment, thereby reducing the cost and enabling various types of process arrangement.

Further, since the processing step can be simplified and the time can be shortened, the productivity can be improved and the manufacturing cost can be lowered.

1 is a view for explaining a molded 3D curved glass.
2 is a flowchart illustrating a method of manufacturing a curved glass according to an embodiment of the present invention.
FIGS. 3 to 6 are schematic views for explaining a stepwise method of manufacturing a curved glass according to an embodiment of the present invention.

Hereinafter, a method of manufacturing a curved glass according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 to 6, a method of manufacturing a curved glass according to an exemplary embodiment of the present invention includes a first step (S10) of heating a glass material 10 to a softening point temperature or higher, A third step S30 in which the glass material 10 heated in the first step S10 is molded using the forming mold 100 and then slowly cooled, And a fourth step S40 of cooling the slowly cooled glass material 10 in the third step S30.

In the first step S10, the glass material 10 is directly heated to a temperature higher than the softening point temperature, that is, approximately 700 to 900 ° C or higher by using a so-called load-lock 20.

That is to say, the glass material 10 can be heated to a temperature higher than the softening point temperature by using the heating heaters 23 and 24 in a state where the glass material 10 is placed on the predetermined holding table 21 in the load lock 20 have. At this time, the configuration of the heating heaters 23 and 24 for directly heating the glass material 10 may be various examples, and it is preferable that the heating process is performed in a closed space (chamber) to prevent heat loss.

In addition, during the first step (S10), the molding die 100 for curved surface molding of the glass material is preheated in advance.

That is, in the second step S20, the molding die 100 is heated to a temperature equal to or lower than the softening point or preheated to a low temperature (within 200 DEG C) according to the properties of the glass material, Prevents damage due to stress due to temperature change.

The preheating operation of the molding die 100 may be performed in a space where the glass material 10 is heated or in a separate processing space.

When the first and second steps S10 and S20 are completed as described above, the glass material 10 heated to a temperature equal to or higher than the softening point is preliminarily mounted on the preformed molding die 100 by using a predetermined conveying means So that a specific portion of the glass material 10 is gradually cooled while being formed into a curved surface. That is, in the third step S30, when the glass material 10 heated to a temperature not lower than the softening point temperature is mounted on the preformed molding die 100 and the molding operation is performed, Can be formed into a curved surface by a working pressure of the forming die 100 by a desired portion (both side edges or the entire surface). While the glass material 10 is curved in this way, the curved glass material 10 is subjected to the slow cooling process by the forming mold 100 having a softening point temperature or lower. Therefore, the molding process and the slow cooling process are performed at the same time without performing the slow cooling process through the separate cooling process after the molding process as in the prior art. Accordingly, the machining process can be simplified, the machining time can be shortened, and the machining cost can be reduced, as well as the yield can be improved, compared with the case of separately performing the molding process and the slow cooling process.

Particularly, since the glass material 10 is not heated while the forming metal mold 100 itself is heated to a temperature higher than the softening point temperature, the time required for heating the forming metal mold 100 can be shortened. Further, since the molding die 100 is not required to be heated to a high temperature, the durability of the molding die 100 can be improved.

Also, conventionally, as the glass material 10 is heated to the softening point temperature or higher by heating the molding die to a temperature higher than the softening point temperature in the molding step, the releasability of the glass material 10 and the molding die after molding is lowered It is not necessary to heat the molding die 100 at a temperature equal to or higher than the softening point temperature as in the present invention and it is not necessary to heat the glass material 10 at a temperature higher than the softening point temperature, The mold releasing performance between the glass material 10 and the molding die 100 is improved after molding because the molding and the freezing operation are performed in a state where the temperature difference between the glass mold 10 and the molding die 100 is generated. Therefore, it is not necessary to use the molding metal mold 100 of the graphite material in consideration of the releasing property, and it is possible to perform the curving process of the glass material by using the metal mold 100 having many advantages over the graphite material . That is, when the glass material 10 is curved using the metal mold 100, it is possible to shorten the time required for heating and cooling the steel mold 100, thereby improving the production yield And it is possible to minimize the transition of the glass material to improve the quality of the glass material, and to prolong the life of the molding die.

In addition, when the metal mold 100 is used, the roughness can be minimized and the flatness can be increased, so that the surface roughness of the processed glass material can be lowered, thereby simplifying the subsequent machining process (polishing, etc.) There is an advantage to be able to do. That is, it is possible to improve the flatness of the surface of the glass material by increasing the releasability of the molding die 100, and there is an advantage that the degree of contamination due to the transition or the like can be reduced.

Further, in performing the molding and gradual cooling steps simultaneously, slow cooling is performed by lowering the temperature to below the set temperature after the molding. Preferably, the slow cooling process is performed while lowering the temperature to the strain point, The molding can be completed completely. At this time, since the mold is slowly cooled using the molding die 100 having a lower temperature than that of the glass material having a relatively high temperature, the cooling time can be shortened and a molding metal made of steel other than graphite can be used. Can be shortened.

Here, it is preferable to proceed until the temperature of the glass material 10 becomes a strain point (450 DEG C to 500 DEG C) or less in the molding and gradual cooling step. Therefore, even if the curved glass 10 'processed after the slow cooling process is moved for the cooling process, the processed shape can be maintained as it is.

As shown in FIG. 4, the forming metal mold 100 may include a lower metal mold 110 and an upper metal mold 120, for example. The lower mold 110 includes a seating part 111 on which the glass material 10 is placed and a curved surface processing part 113 connected to the seating part 111 and having a curved surface shape for curving the glass material 10 Respectively.

The upper mold 120 is provided with a pressing portion 121 corresponding to the seating portion 111. The pressing portion 121 is formed with a curved surface protrusion 123 having a curved surface corresponding to the curved surface machining portion 113. Accordingly, when the glass material 10 is placed in the seating part 111 and the lower and upper molds 110 and 120 are brought into close contact with each other to press the glass material 10, as shown in FIG. 4, The material 10 may be curved to a desired shape by the mold shapes of the lower and upper dies 110 and 120. A lower heater 130 and an upper heater 140 are installed in the lower mold 110 and the upper mold 120 to heat the lower mold 110 and the upper mold 120, respectively. The molding die 100 is installed inside the closed chamber 20 and is shielded from the outside, thereby reducing heat loss.

As described above, the so-called curved glass 10 ', which has been subjected to the molding and gradual cooling processes, is moved to a separate cooling space (zone), and the molding process can be completed through the cooling process of the fourth step S40 . In the fourth step S40, that is, the cooling step may be performed in the same space in which the third step S30 has been performed. Alternatively, as shown in FIG. 6, a separate cooling space 40 may be provided A cooling process can be performed.

Therefore, according to the present invention, since the space required for the curved surface processing of the glass material can be minimized, it is possible to simplify the equipment and make various types of equipment configurations, and simplify the entire process.

Here, the cooling space 40 may be a separate chamber, a cooling jig 41 is installed in the chamber, and a cooling means 43 for circulating the cooling fluid to the cooling jig 41 So that the curved glass 10 'can be effectively cooled by cooling the cooling jig 41. [

Further, the cooling zone 40 may be provided with a cooling fan 45 for air-cooling the moved curved glass 10 '.

More preferably, the glass material 10 heated above the softening point temperature in the first step S10 is transferred to a position for the third step S30 using the transfer means (pick-up unit) 100), a heater is provided in the contact portion (pick-up portion) of the glass material 10 of the pick-up unit to pick up and transport the glass material 10 while heating the pick-up unit at a temperature higher than the softening point temperature (S50). In this way, during the transfer of the glass material 10 in the step S50, heating can be performed to maintain the temperature higher than the softening point temperature, and the glass material 10 is transferred to the forming mold 100 while being maintained at the softening point temperature or more So that it is possible to effectively perform the molding and slow cooling steps. Here, various examples are available for the conveying means pick-up unit and the like for conveying the glass material 10. In this case, by heating and heating the contact part for clamping, adsorbing or supporting the glass material 10, The heat loss of the glass material 10 can be prevented. Accordingly, even after the glass material 10 preheated above the softening point temperature is moved to the forming position, it can be maintained at the softening point temperature or higher, so that the molding process can be normally performed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is obvious to those who have. Therefore, such modifications or variations should not be individually understood from the technical spirit and viewpoint of the present invention, and modified embodiments should be included in the claims of the present invention.

10 .. Glass material 10 '.. Curved glass
100 .. Molding mold 110 .. Lower mold
120. Upper mold 130 .. Lower heater
140. Top heater

Claims (5)

A first step of directly heating the glass material to be processed at a temperature higher than the softening temperature;
A second step of preheating a molding metal formed of a metal material to a temperature below the softening temperature for molding the glass material;
A third step of slowly cooling the glass material heated in the first step to a desired temperature by slowly attaching the glass material heated in the second step to a preformed mold and shaping the glass material into a desired shape;
A fourth step of cooling the glass material having undergone the third step to a strain temperature or lower; And
And heating the glass material heated above the softening temperature in the first step to a temperature above the softening temperature of the portion of the pick-up unit that conveys the glass material when the glass material is moved for the third step, ,
Wherein the molding die is maintained at a lower temperature than the glass material so that a temperature difference is generated so as to improve releasability between the glass material and the molding die so that the molding die can be used as a metal material.
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