JP2009114017A - Method for producing molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a molding where an air trap does not remain in the molding by preventing the occurrence of the air trap formed between molding faces and molding materials. <P>SOLUTION: When the molding is obtained by arranging the molding materials between a pair of an upper die 12 and a lower die 14, heating, softening and pressing, the molding materials are a first spherical material 20 having a smaller radius of curvature r<SB>g</SB>than a radius of curvature r<SB>d</SB>of the lower die 14 and a second material 22 other than the first material and the first material 20 and the second material 22 are molded by a pair of the upper die 12 and the lower die 14. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a molded product that obtains a molded product by softening and pressing a thermoplastic material.

Conventionally, for example, as shown in FIG. 13, when a molded product having a spherical convex surface is formed by an upper mold 12 and a lower mold 14 using a ball material (ball preform) 20, the radius of curvature r _g of the ball material 20. If is greater than the radius of curvature r _d of the molding surface 14a of the lower die 14, there is a disadvantage that unless good transfer accuracy can not be obtained escape the air in the air enclosure 28 formed on the tip.

  In order to solve this problem, for example, Patent Document 1 discloses a technique in which a ball material is provided with a groove through which air escapes in advance and the air is allowed to escape to the outside. Thereby, the air pocket (air trap) which can be made into a molded article is prevented.

Further, for example, Patent Document 2 discloses a technique in which the inside of a mold set cavity is decompressed to a vacuum so as not to form air. Thereby, it is possible to prevent the occurrence of transfer failure of the gas residue on the optical function surface of the molded product without elaborating the shape of the glass gob.
JP 2006-151780 A Japanese Patent Laid-Open No. 9-30818

However, in Patent Document 1, by providing grooves in the ball material in advance, it takes time and cost to process the grooves, and there is a risk that the grooves will remain on the molded product after molding.
Moreover, in patent document 2, the vacuum apparatus etc. for decompressing a shaping | molding apparatus and avoiding enclosure of air become large-scale, and it leads to the increase in manufacturing cost. Further, because of the vacuum, volatilization of the volatile material may be promoted and the surface of the molded product may become cloudy.

  The present invention has been made to solve such a problem, and prevents the formation of an air pocket formed between the molding surface of the mold and the molding material so that the air pool does not remain in the molded product. It aims at providing the manufacturing method of the molded article which ensured the shape transcription | transfer of the molding surface of the said type | mold.

In order to achieve the object, the invention according to claim 1
In the method of manufacturing a molded product, a molded material is obtained by placing a molding material between a pair of molding dies and softening by heating and pressing.
The molding material has a spherical first material having a radius of curvature smaller than the radius of curvature of the mold, and another second material, and the first material and the second material are molded by the pair of molding dies. A method for producing a molded product characterized by the above.

The invention according to claim 2 is the method of manufacturing a molded article according to claim 1,
The outer surface of the second material is positioned by being supported by a support member.
The invention according to claim 3 is the method of manufacturing a molded article according to claim 2,
The support member is a cylindrical sleeve that fits an upper die and a lower die constituting the pair of forming dies.

The invention according to claim 4 is the method for producing a molded article according to claim 2,
The support member is a cylindrical positioning member that is fitted to the inner surface of a cylindrical sleeve that fits the upper mold and the lower mold constituting the pair of molds.

The invention according to claim 5 is the method for producing a molded article according to claim 2,
The second material is larger than the first material.
The invention according to claim 6 is the method for producing a molded article according to claim 2,
The total volume of the first material and the second material is adjusted to be equal to the volume of the molded product.

The invention according to claim 7 is the method of manufacturing a molded article according to claim 1,
The second material has a shape in which a part of a sphere is cut out by a plane.
The invention according to claim 8 is the method of manufacturing a molded article according to claim 1,
The outer diameter of the second material is equal to the outer diameter of the molded product.

The invention according to claim 9 is the method of manufacturing a molded article according to claim 1,
The second material is cylindrical and the end surface is a spherical surface or a flat surface.

  According to the present invention, the molding material disposed between the pair of molding dies has a spherical first material having a radius of curvature smaller than the radius of curvature of the die, and another second material, and the first material, By molding the second material with a pair of molding dies, it is possible to prevent the occurrence of air pockets formed between the molding surface of the mold and the molding material so as not to remain in the molded product.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
1 to 3 show a method for manufacturing a molded article according to the first embodiment.

FIG. 1 shows an assembly process and a heating process of a mold set containing molding materials, FIG. 2 shows a molding process during molding, and FIG. 3 shows a process after completion of molding.
In FIG. 1, the mold set 10 includes an upper mold 12 and a lower mold 14 as a pair of molding molds, a cylindrical sleeve 16, and a cylindrical positioning member 18 as a support member.

Upper mold 12 forms a flanged cylindrical shape and has a large-diameter flange portion 12 ₁ of the columnar portion 12 ₂ of a small diameter. This columnar portion 12 the end surface of the _second axial, flat forming surface 12a is formed.

The lower mold 14 also forms a flanged cylindrical shape and has a large diameter flange portion 14 ₁ of the small diameter and the columnar portion 14 _2. This end surface of the columnar portion 14 ₂ in the axial direction (O direction), flat forming surface 14b is formed around the concave spherical molding surface 14a. The molding surface 14a is not limited to a spherical surface but may be an aspherical surface.

Tubular sleeve 16 has a cylindrical shape, it is fitted on the outer circumferential surface of the columnar portion 14 ₂ of the lower die 14. Further, the cylindrical positioning member 18 forms a stepped cylindrical shape, and has _a large-diameter flange portion 18 diameter of the cylindrical portion 18 _2.

Flange 18 ₁ of the cylindrical positioning member 18 is in contact with the one open end face of the axial direction of the tubular sleeve 16 (O-axis direction) (the side close to the upper mold 12), the tubular portion 18 ₂ is cylindrical The inner surface of the sleeve 16 is fitted. The length of the cylindrical positioning member 18 in the axial direction (O-axis direction) is set to about half of the cylindrical sleeve 16.

  The upper mold 12 is fitted and inserted from one axial end side of the cylindrical positioning member 18, and the lower mold 14 is fitted and inserted from the axial other end side of the cylindrical sleeve 16. The upper mold 12 and the lower mold 14 are arranged so that the molding surfaces 12a and 14a face each other.

  In the present embodiment, the upper mold 12 is slidable in the axial direction of the cylindrical positioning member 18. Further, between the molding surface 12a of the upper mold 12 and the molding surface 14a of the lower mold 14, a spherical first material 20 as a molding material and another spherical second material 22 are axially arranged. It is arranged above and below. The first material 20 is placed substantially at the center of the molding surface 14 a of the lower mold 14.

The second material 22 is disposed between the molding surface 12 a of the upper mold 12 in a state of being placed on the first material 20. The first material 20 has a small radius of curvature _{r g} than the radius of curvature _{r d} of the molding surface 14a of the lower mold _{14 (r d ≧ r g)} .

Thereby, as will be described later, the air between the molding surface 14a of the lower mold 14 and the first material 20 is pushed out to the outer peripheral side, and the occurrence of air pockets in the molded product is avoided.
Further, the radius of curvature r _G of the second material 22 has a larger radius of curvature than that of the first material 20. The second material 22 is supported by contacting the outer surface thereof with the inner surface of the cylindrical positioning member 18. In this state, the first material 20 and the second material 22 are in contact at one point in the axial direction. Further, the axis connecting the centers of the first material 20 and the second material 22 is held so as to coincide with the mold center axis O.

  Thus, at the time of molding, the first material 20 is first accurately transferred to the molding surface 14a of the lower mold 14, and the softened first material 20 and second material 22 are evenly spread from the center toward the outer peripheral side. To go. For this reason, a molded product with good transfer accuracy can be obtained. On the other hand, if the axis connecting the centers of the first material 20 and the second material 22 does not coincide with the mold center axis O, the shape accuracy of the molded product may be deteriorated.

  Furthermore, as is common to all the embodiments including this embodiment, the total volume of the first material 20 and the second material 22 is adjusted to be equal to or slightly smaller than the volume of the molded product. ing.

Thereby, when shape | molding the molded article of a desired shape, the magnitude | size (outer diameter) of the 1st raw material 20 arrange | positioned at the molding surface 14a of the lower mold | type 14 is determined first. In that case, the size of the first material 20 a (the radius of curvature r _g), it is important to reduce than the radius of curvature r _d of the molding surface 14a of the lower mold 14. Next, the size (outer diameter) of the second material 22 can be determined by subtracting the volume of the first material 20 from the volume of the molded product.

Thus, for example, small curvature radius r _g of the lower mold 14 the first material 20 of the lower placed on the molding surface 14a of the upper radius of curvature r _G is greater combination of the molding material of the second material 22 is selected The Thus, the curvature of the first material 20 of the lower radius r _g is small, the curvature radius r _G of the above the second material 22 is large, it is possible to take the diameter of the molding surface 12a of the upper mold 12 increases, When the molded product is an optical element, the optically effective surface can be widened.

  When the total volume of the first material 20 and the second material 22 is larger than the volume of the molded product, the glass material enters the gap between the upper mold 12 and the lower mold 14 and the cylindrical sleeve 16 and the like. This may cause burrs or damage the mold due to the pressure of the glass material. For this reason, it is desirable that the total volume of the first material 20 and the second material 22 is equal to or less than the volume of the molded product.

  In the present embodiment, for example, a commercially available optical glass material is used as the first material 20 and the second material 22. In addition to the glass material, for example, a synthetic resin can be used.

The upper mold 12, the lower mold 14, the cylindrical sleeve 16, and the cylindrical positioning member 18 are finished by grinding and polishing a cemented carbide such as tungsten carbide (WC).
In the heating step, the first material 20 and the second material 22 are heated from the glass transition point to a temperature near the glass softening point. As a result, the first material 20 and the second material 22 are softened to a deformable viscosity.

  Next, as shown in FIG. 2, at the time of molding, the upper mold 12 moves closer to the inside of the cylindrical positioning member 18 in the axial direction (O-axis direction) relative to the lower mold 14 and presses the second material 22. Accordingly, the second material 22 moves toward the first material 20 in the cylindrical positioning member 18. Thus, the second material 22 moves closer to the first material 20, and the softened first material 20 is crushed by the urging pressure from the second material 22, and the two are joined at the interface.

At this time, since the second material 22 is larger than the first material 20, the first material 20 is crushed first by the weight of the second material 22. In this case, the air of curvature radius r _g of the first material 20 is smaller than the radius of curvature r _d of the concave shaping surface 14a of the lower mold 14, which was present in the concave molding surface 14a of the lower mold 14 Is extruded from the center toward the outer peripheral side.

  The air thus pushed out is discharged from a gap formed between the concave molding surface 14a and the outer peripheral surface of the spherical first material 20 before the molding is completed. The discharged air escapes from a slight gap between the upper mold 12 and the lower mold 14 and the cylindrical sleeve 16. In this way, it is avoided that an air pocket is generated between the concave molding surface 14 a of the lower mold 14 and the spherical first material 20.

Similarly, as shown in FIG. 2, the curvature radius r _G of the second material 22 is smaller than the curvature radius (∞) of the molding surface (plane) 12 a of the upper mold 12, so that the outer surface of the spherical second material 22 And the air existing between the molding surface 12a of the upper mold 12 are pushed out from the center toward the outer peripheral side. In this way, it is possible to avoid the accumulation of air between the molding surface 12 a of the upper mold 12 and the spherical second material 22.

FIG. 3 shows a state after the molding is completed.
The molding completed state, the flange portion 12 ₁ of the upper mold 12 is positioned in contact with the flange portion 18 ₁ of the cylindrical positioning member 18. In this state, the first material 20 and the second material 22 are completely fused and a molded product (optical element) 36 is obtained.

This molded product 36 has a shape in which a spherical portion 36b protrudes from the center of a thick cylindrical portion 36a, and is used as an optical lens.
According to this embodiment, the first material 20 of small radius of curvature r _g than the radius of curvature r _d of the concave shaping surface 14a of the lower mold 14 abuts the center of the concave molding surface 14a of the lower mold 14 By molding, it is possible to mold while discharging air during the molding. For this reason, generation | occurrence | production of the air pocket formed between the concave molding surface 14a of the lower mold | type 14 and the 1st raw material 20 can be prevented, and this air pocket can be prevented from remaining in a molded product.

For this reason, the highly accurate molded product 36 without a crack and an air pocket can be obtained.
Moreover, since the volume shortage with respect to the molded product 36 when only the first material 20 is used can be adjusted by the second material 22, a molded product having a desired shape can be obtained by adjusting the volume of the second material 22. Obtainable. Furthermore, a molded product with high shape accuracy can be obtained by adjusting the total volume of the first material 20 and the second material 22 to be equal to the volume of the molded product.

Further, by using the cylindrical positioning member 18 as a part of the mold, it is possible to cope with the change in the shape of the cylindrical positioning member 18 when the outer shape of the molded product is changed.
[Second Embodiment]
FIG. 4 shows a method for manufacturing a molded article according to the second embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  In 1st Embodiment, the case where the cylindrical positioning member 18 fitted to the inner surface of the cylindrical sleeve 16 was used as a supporting member was demonstrated. However, for example, as shown in FIG. 4, the mold set 10 may be configured not to use the cylindrical positioning member 18.

  According to FIG. 4, the mold set 10 includes an upper mold 12, a lower mold 14, and a cylindrical sleeve 16 as a support member. The upper mold 12 and the lower mold 14 are fitted into the cylindrical sleeve 16 from both ends of the cylindrical sleeve 16 so that the molding surfaces 12a and 14a face each other. The first material 20 is placed on the molding surface 14 a of the lower mold 14. The second material 22 is disposed between the molding surface 12 a of the upper mold 12 in a state of being placed on the first material 20.

  In FIG. 4, the second material 22 is not supported on the inner surface of the cylindrical sleeve 16. For this reason, it may be difficult to position the second material 22 so as to coincide with the mold center axis O. In order to solve this, for example, the size of the second material 22 may be set to a size that abuts against the inner surface of the cylindrical sleeve 16.

  Or it is good to form the some hole which can insert the positioning member not shown in the side surface of the cylindrical sleeve 16 previously. By doing so, the second material 22 can be positioned from the side by a positioning member (not shown).

Other configurations and operations are the same as those described in the first embodiment.
According to this embodiment, the radius of curvature r _g of the first material 20 is smaller than the radius of curvature r _d of the molding surface 14a of the lower mold 14, between the molding surface 14a and the first material 20 of the lower mold 14 It is possible to prevent the air accumulation from occurring. Moreover, since the cylindrical positioning member 18 as in the first embodiment is not used, the configuration of the mold set 10 can be simplified.
[Third Embodiment]
5 and 6 show a method for manufacturing a molded article according to the third embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

In the present embodiment, an example is shown in which the outer surface of the spherical second material 22 is supported and positioned by the support member (18).
That is, as shown in FIG. 5, a cylindrical positioning member 18 as a support member is fitted into the inner surface of the cylindrical sleeve 16. The cylindrical positioning member 18 is placed around the molding surface 14a of the lower mold 14 and on the planar molding surface 14b. The spherical first material 20 is placed on the molding surface 14 a of the lower mold 14. The radius of curvature r _g of the first material 20 is smaller than the radius of curvature r _d of the molding surface 14a of the lower mold 14. The second material 22 is supported on the upper edge of the cylindrical positioning member 18.

  That is, the cylindrical positioning member 18 supports the second material 22 at the inner peripheral edge of the other end in a state where one end in the axial direction is placed on the lower mold 14. The second material 22 is positioned so that the center thereof coincides with the mold center axis O while being supported by the cylindrical positioning member 18. Further, the second material 22 is not in contact with the first material 20 in a state where it is placed on the cylindrical positioning member 18. By adjusting the volume of the second material 22, the volume of the finished product can be finely adjusted.

In this embodiment, the radius of curvature r _g of the first material 20 is smaller than the radius of curvature r _d of the molding surface 14a of the lower mold 14, between the molding surface 14a and the first material 20 of the lower mold 14 There is no air pocket.

  Further, since the first material 20 and the second material 22 are not in contact with each other when the mold set 10 is assembled, the centers of the first material 20 and the second material 22 are individually aligned with the mold center axis O. Is easy. Further, although the first material 20 and the second material 22 are individually heated and softened, there is no possibility that the first material 20 is crushed by the weight of the second material 22 during the heating.

  It should be noted that the first material 20 and the second material 22 do not have to be non-contact in the assembled state of the mold set 10, and may be in contact. However, it is preferable to arrange the first material 20 and the second material 22 so that their centers coincide with the mold center axis O when they are brought into contact with each other.

FIG. 6 shows a state after the molding is completed.
The molding completed state, the flange portion 12 ₁ of the upper mold 12 is positioned in contact with the upper end surface of the tubular sleeve 16. In this state, the first material 20 and the second material 22 are completely fused to form a molded product (optical element) 36.

In this molded product 36, a spherical portion 36b protrudes from the center of one end of a thick cylindrical portion 36a, and a flange portion 36c is provided at the other end of the cylindrical portion 36a.
According to the present embodiment, even when it is desired to change the outer diameter (cylindrical portion) of the molded product, it can be dealt with by changing the inner diameter of the cylindrical positioning member 18. Therefore, even when it is desired to change the shape of the molded product, it is possible to cope with the change in the cylindrical positioning member 18 without changing the constituent members of the mold set 10. For this reason, the freedom degree of design increases.

  Further, since the first material 20 and the second material 22 are not in contact with each other, the respective centers can be individually matched with the mold center axis O. Furthermore, the shape of the molded product can be easily changed by using the cylindrical positioning member 18 as a part of the mold.

Also in this case, the curvature radius _{r g} of the first material 20 is smaller than the radius of curvature _{r d} of the molding surface 14a of the lower mold 14, between the molding surface 14a and the first material 20 of the lower mold 14 Air accumulation does not occur.
[Fourth Embodiment]
FIG. 7 shows a method for manufacturing a molded article according to the fourth embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

In the present embodiment, the mold set 10 includes an upper mold 12 and a lower mold 14 as a pair of molding molds, a cylindrical sleeve 16, and a cylindrical positioning member 18.
Upper mold 12 has a large-diameter flange portion 12 ₁ of the columnar portion 12 ₂ of a small diameter, flat forming surface 12a on the end face in the axial direction of the columnar portion 12 ₂ is formed.

The lower mold 14 also has a large-diameter flange portion 14 ₁ of the columnar portion 14 ₂ of a small diameter, the end face of the axial direction of the columnar portion 14 _2, concave spherical molding surface 14a is formed .
Between the molding surface 12a of the upper mold 12 and the molding surface 14a of the lower mold 14, a spherical first material 20 as a molding material and a spherical second material 22 different from this are arranged vertically. ing. The first material 20 is placed on the molding surface 14 a of the lower mold 14. The second material 22 is disposed between the molding surface 12 a of the upper mold 12 in a state of being placed on the first material 20.

The first material 20 has a small radius of curvature _{r g} than the radius of curvature _{r d} of the molding surface 14a of the lower mold _{14 (r d ≧ r g)} .
As shown in FIG. 7, the second material 22 placed on the first material 20 has a smaller radius of curvature than the first material 20. The second material 22 is supported by contacting the outer surface of the second material 22 with the inner surface of the cylindrical positioning member 18. In this state, the centers of the first material 20 and the second material 22 are held so as to coincide with the mold center axis O. In the example of FIG. 7, it is set to a value equal to the diameter of the columnar portion 12 ₂ of the upper mold 12 and the diameter of the second material 22.

In the present embodiment, the second material 22 plays a role of supplementing the volume of the shortage of the molded product that is insufficient for the volume of the first material 20. Again, the first material 20, because it has a smaller radius of curvature r _g than the radius of curvature r _d of the molding surface 14a of the lower mold 14, there is no possibility that air pockets occur in the molded article.

Although the shape of the molded product molded in this case is not shown, it has a cylindrical appearance and a spherical surface protruding from the center. However, since the diameter of the second material 22 is smaller than the diameter of the first material 20, the diameter of the upper mold columnar portion 12 ₂ is reduced, thus the diameter of the effective surface of the upper surface is reduced.
[Fifth Embodiment]
FIG. 8 shows a method for manufacturing a molded article according to the fifth embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  In the present embodiment, between the molding surface 12a of the upper mold 12 and the molding surface 14a of the lower mold 14, a spherical first material 20 as a molding material, and a spherical second material 22 different from this, Are arranged one above the other. The first material 20 is placed on the molding surface 14 a of the lower mold 14.

  The second material 22 is disposed between the molding surface 12 a of the upper mold 12 in a state of being placed on the first material 20. The second material 22 placed on the first material 20 has a larger radius of curvature than the first material 20.

The first material 20 has a small radius of curvature _{r g} than the radius of curvature _{r d} of the molding surface 14a of the lower mold _{14 (r d ≧ r g)} .
Further, as shown in FIG. 8, the second material 22 is supported by contacting the outer surface thereof with the inner surface of the cylindrical positioning member 18. In this state, the centers of the first material 20 and the second material 22 are held so as to coincide with the mold center axis O. In the example of FIG. 8, it is set to a value equal to the diameter of the columnar portion 12 ₂ of the upper mold 12 and the diameter of the second material 22.

Again, the first material 20, because it has a smaller radius of curvature r _g than the radius of curvature r _d of the molding surface 14a of the lower mold 14, there is no possibility that air pockets occur in the molded article.
Although the shape of the molded product molded in this case is not shown, the appearance is a columnar shape with a spherical surface protruding in the center. However, the diameter of the second material 22 is greater than the first material 20, the diameter of the upper mold columnar portion 12 ₂ is increased, thus the diameter of the effective surface of the top surface is increased.

Further, when FIG. 7 (fourth embodiment) is compared with FIG. 8 (this embodiment), the thickness of the molded product is equal by making the total sum of the volumes of the first material 20 and the second material 22 equal. It is. On the other hand, the diameter of the molding surface 12a of the upper mold 12 is larger in FIG. For this reason, the molding material can be pressed by the molding surface 12a of the upper die 12 having a large diameter, and the molding surface 12a can be transferred to the second material 22, so that the optical effective diameter when the molded product is an optical element can be increased. It can be taken big.
[Sixth Embodiment]
9 to 11 show a method for manufacturing a molded article according to the sixth embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

  In this embodiment, the 2nd raw material 22 has the shape of the partial sphere which cut off a part of sphere with the plane. Here, the partial sphere means a shape composed of a spherical surface and a plane, a hemisphere, a shape thinner than the hemisphere, or a shape thicker than the hemisphere.

  In FIG. 9, the mold set 10 includes an upper mold 12, a lower mold 14, and a cylindrical sleeve 16 as a pair of molds. The upper mold 12 and the lower mold 14 are fitted and inserted from both ends of the cylindrical sleeve 16 so that the molding surfaces 12 a and 14 a face each other inside the cylindrical sleeve 16.

Upper mold 12 forms a flanged cylindrical shape and has a large-diameter flange portion 12 ₁ of the columnar portion 12 ₂ of a small diameter. The end face of the axial direction of the columnar portion 12 _2, flat forming surface 12a is formed.

The lower mold 14 also forms a flanged cylindrical shape and has a large diameter flange portion 14 ₁ of the small diameter and the columnar portion 14 _2. This end surface of the columnar portion 14 ₂ of the axial, flat forming surface 14b is formed around the concave spherical molding surface 14a. The molding surface 14a is not limited to a spherical surface but may be an aspherical surface.

The upper mold 12 is slidable in the axial direction inside the cylindrical sleeve 16. Further, between the molding surface 12a of the upper mold 12 and the molding surface 14a of the lower mold 14, a spherical first material 20 as a molding material and a partial spherical second material 22 different from this are vertically arranged. Is arranged. The first material 20 is placed on the molding surface 14 a of the lower mold 14. The first material 20 has a small radius of curvature _{r g} than the radius of curvature _{r d} of the molding surface 14a of the lower mold _{14 (r d ≧ r g)} .

  The second material 22 that forms a partial sphere has an outermost diameter that is larger than that of the first material 20. The first material 20 and the second material 22 are in contact at one point. The second material 22 is supported by inserting the outer surface of the second material 22 into the inner surface of the cylindrical sleeve 16 in a fitting manner. Therefore, when the second material 22 forming the partial sphere is a hemispherical sphere, the diameter of the sphere becomes the inner diameter of the cylindrical sleeve 16.

In this state, the centers of the first material 20 and the second material 22 are held so as to coincide with the mold center axis O.
As described in the first embodiment, the total volume of the first material 20 and the second material 22 is adjusted to be equal to or slightly smaller than the volume of the molded product.

  In FIG. 10, at the time of molding, the first material 20 and the second material 22 are heated from the glass transition point to a temperature near the glass softening point. Next, the upper mold 12 moves closer to the lower mold 14 and presses the second material 22. Accordingly, the second material 22 moves toward the first material 20 in the cylindrical sleeve 16. Thus, the second material 22 moves closer to the first material 20, and the softened first material 20 is crushed by the urging pressure from the second material 22 and joined at the interface.

At this time, since the second material 22 is larger than the first material 20, the first material 20 is crushed first by the weight of the second material 22. In this case, the air of curvature radius r _g of the first material 20 is smaller than the radius of curvature r _d of the concave shaping surface 14a of the lower mold 14, which was present in the concave molding surface 14a of the lower mold 14 Is extruded from the center toward the outer peripheral side.

Similarly, the radius of curvature r _G of the second material 22 is smaller than the radius of curvature (∞) of the molding surface 12 a of the upper mold 12, and therefore exists between the second material 22 and the molding surface 12 a of the upper mold 12. The air that has been pushed out is pushed from the center toward the outer peripheral side.

  The air pushed out as described above is discharged from a gap formed between the concave molding surface 14a and the outer peripheral surface of the spherical first material 20 before the molding is completed. The discharged air escapes from a slight gap between the upper mold 12 and the lower mold 14 and the cylindrical sleeve 16. In this way, it is avoided that an air pocket is generated between the concave molding surface 14 a of the lower mold 14 and the spherical first material 20.

FIG. 11 shows a state after the molding is completed.
The molding completed state, the flange portion 12 ₁ of the upper mold 12 is positioned in contact with the upper end surface of the tubular sleeve 16. In this state, the first material 20 and the second material 22 are completely fused to form a molded product (optical element) 36.

The molded product 36 has a shape in which a spherical portion 36b protrudes from the center of a thick cylindrical portion 36a.
According to the present embodiment, since the outer diameter of the second material 22 is equal to the inner diameter of the sleeve, the position of the material can be adjusted with the cylindrical sleeve 16 without using a separate member for positioning the material. Is possible.

Furthermore, since the outer diameter of the second material 22 is equal to the outer diameter of the molded product, the amount of deformation of the glass material can be reduced. This shortens the molding time.
Again, the first material 20, because it has a smaller radius of curvature r _g than the radius of curvature r _d of the molding surface 14a of the lower mold 14, there is no possibility that air pockets occur in the molded article.
[Seventh Embodiment]
FIG. 12 shows a method for manufacturing a molded article according to the seventh embodiment. In addition, the same code | symbol is attached | subjected and demonstrated to the member which is the same as that of 1st Embodiment, or corresponds.

In the present embodiment, the second material 22 has a cylindrical shape, one end surface having a spherical surface 22a and the other end surface having a flat surface 22b.
In FIG. 12, the mold set 10 includes an upper mold 12, a lower mold 14, and a cylindrical sleeve 16 as a pair of molds. The upper mold 12 and the lower mold 14 are fitted and inserted from both ends of the cylindrical sleeve 16 so that the molding surfaces 12 a and 14 a face each other inside the cylindrical sleeve 16.

Upper mold 12 forms a flanged cylindrical, has a large-diameter flange portion 12 ₁ of the columnar portion 12 ₂ of a small diameter, the end face of the axial direction of the columnar portion 12 _2, flat forming surface 12a is formed ing.
Moreover, none of the lower die 14 is also flanged cylindrical, has a large-diameter flange portion 14 ₁ of the columnar portion 14 ₂ of a small diameter, the end face of the axial direction of the columnar portion 14 _2, concave spherical molding surface 14a Further, a planar molding surface 14b is formed around the periphery.

The upper mold 12 is slidable in the axial direction inside the cylindrical sleeve 16. Further, between the molding surface 12a of the upper mold 12 and the molding surface 14a of the lower mold 14, a spherical first material 20 as a molding material and a second material 22 different from this are arranged vertically. ing. The first material 20 is placed on the molding surface 14 a of the lower mold 14. The first material 20 has a small radius of curvature _{r g} than the radius of curvature _{r d} of the molding surface 14a of the lower mold _{14 (r d ≧ r g)} .

  The second material 22 has a cylindrical surface on one side, a spherical surface 22a on one end surface, and a flat surface 22b on the other end surface. Here, the spherical surface 22a is used to include concave and convex curved surfaces. Further, the outermost diameter of the second material 22 is set to be larger than that of the first material 20. The second material 22 is supported by fitting its outer surface (cylindrical surface) into the inner surface of the cylindrical sleeve 16. The first material 20 and the second material 22 are in contact at one point.

  In this state, the axis line connecting the centers of the first material 20 and the second material 22 is held so as to coincide with the mold center axis O. At this time, since the second material 22 has a columnar shape, the central axis thereof can easily coincide with the mold central axis O by being inserted into the cylindrical sleeve 16.

As described in the first embodiment, the total volume of the first material 20 and the second material 22 is adjusted to be equal to or slightly smaller than the volume of the molded product.
Although not shown, at the time of molding, the first material 20 and the second material 22 are heated from the glass transition point to a temperature near the glass softening point. Next, the upper mold 12 moves closer to the lower mold 14 and presses the second material 22. Accordingly, the second material 22 moves toward the first material 20 in the cylindrical sleeve 16. Thus, the second material 22 moves closer to the first material 20, and the softened first material 20 is crushed by the urging pressure from the second material 22 and joined at the interface.

At this time, since the second material 22 is larger than the first material 20, the first material 20 is crushed first by the weight of the second material 22. In this case, the air of curvature radius r _g of the first material 20 is smaller than the radius of curvature r _d of the concave shaping surface 14a of the lower mold 14, which was present in the concave molding surface 14a of the lower mold 14 Is extruded from the center toward the outer peripheral side.

The extruded air is discharged from a gap formed between the concave molding surface 14a and the outer peripheral surface of the spherical first material 20 before the molding is completed.
Similarly, since the radius of curvature r _G of the spherical surface 22a at one end of the second material 22 is smaller than the curvature radius (∞) of the molding surface 12a of the upper mold 12, the molding of the spherical surface 22a of the second material 22 and the upper mold 12 is performed. The air existing between the surface 12a is pushed out from the center toward the outer peripheral side.

  The air discharged by the above escapes from a slight gap between the upper mold 12 and the lower mold 14 and the cylindrical sleeve 16. In this way, it is avoided that an air pocket is generated between the concave molding surface 14 a of the lower mold 14 and the spherical first material 20.

Although not shown, the molding completed state, the flange portion 12 ₁ of the upper mold 12 is positioned in contact with the upper end surface of the tubular sleeve 16. In this state, the first material 20 and the second material 22 are completely fused to form a molded product (optical element) 36.

Similar to the one shown in FIG. 11 (sixth embodiment), this molded product 36 has a shape in which a spherical portion 36b protrudes from the center of a thick cylindrical portion 36a.
According to the present embodiment, since the outer diameter of the second material 22 is equal to the inner diameter of the sleeve, the position of the material can be adjusted with the cylindrical sleeve 16 without using a separate member for positioning the material. Is possible.

  Furthermore, since the outer diameter of the second material 22 is equal to the outer diameter of the molded product, the amount of deformation of the glass material can be reduced. This shortens the molding time. Further, since the second material 22 has a columnar shape, the central axis thereof can be easily aligned with the mold central axis O by being inserted into the cylindrical sleeve 16.

It is a figure which shows the manufacturing method of the molded article of 1st Embodiment. It is a figure which shows the manufacturing method of the molded article of 1st Embodiment. It is a figure which shows the manufacturing method of the molded article of 1st Embodiment. It is a figure which shows the manufacturing method of the molded article of 2nd Embodiment. It is a figure which shows the manufacturing method of the molded article of 3rd Embodiment. It is a figure which shows the manufacturing method of the molded article of 3rd Embodiment. It is a figure which shows the manufacturing method of the molded article of 4th Embodiment. It is a figure which shows the manufacturing method of the molded article of 5th Embodiment. It is a figure which shows the manufacturing method of the molded article of 6th Embodiment. It is a figure which shows the manufacturing method of the molded article of 6th Embodiment. It is a figure which shows the manufacturing method of the molded article of 6th Embodiment. It is a figure which shows the manufacturing method of the molded article of 7th Embodiment. It is a figure which shows the manufacturing method of the conventional molded article.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Type set 12 Upper mold | type 12 ₁ flange part 12 ₂ columnar part 12a Molding surface 14 Lower mold 14 ₁ flange part 14 ₂ columnar part 14a Molding surface 14b Molding surface 16 Cylindrical sleeve 18 Cylindrical positioning member 18 ₁ Flange part 18 ₂ cylinder Shaped part 20 First material 22 Second material 22a Spherical surface 22b Plane 28 Air sealing part 36 Molded product 36a Columnar part 36b Spherical part 36c Flange part

Claims (9)

In the method of manufacturing a molded product, a molded material is obtained by placing a molding material between a pair of molding dies and softening by heating and pressing.
The molding material has a spherical first material having a radius of curvature smaller than the radius of curvature of the mold, and another second material, and the first material and the second material are molded by the pair of molding dies. A method for producing a molded product characterized by the above. The method for manufacturing a molded product according to claim 1, wherein the outer surface of the second material is positioned by being supported by a support member. The method for manufacturing a molded product according to claim 2, wherein the support member is a cylindrical sleeve that fits an upper die and a lower die constituting the pair of molding dies. The said support member is a cylindrical positioning member fitted to the inner surface of the cylindrical sleeve which fits the upper mold | type and lower mold | type which comprise a pair of said shaping | molding die. Manufacturing method of molded products. The method for producing a molded product according to claim 2, wherein the second material is larger than the first material. The method for manufacturing a molded product according to claim 2, wherein the total volume of the first material and the second material is adjusted to be equal to the volume of the molded product. The method for producing a molded product according to claim 1, wherein the second material has a shape obtained by cutting a part of a sphere with a flat surface. The method for manufacturing a molded product according to claim 1, wherein the outer diameter of the second material is equal to the outer diameter of the molded product. The method for manufacturing a molded product according to claim 1, wherein the second material is cylindrical and the end surface is a spherical surface or a flat surface.