JP2820762B2 - Heat compression molding method of plastic lens - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for hot compression molding of a plastic lens, and is particularly used for molding a high precision plastic lens.

(Prior Art) As a prior art, there is a plastic lens apparatus method of manufacturing a lens material by injection molding and then heating and compressing a material cut by a lathe as in a manufacturing method described in Japanese Patent Publication No. 1-39337. is there.

(Problems to be Solved by the Invention) However, according to the above-mentioned conventional method, it is necessary to gate-cut an injection-molded molded product. It is very difficult to hold and convey the gate-cut lens, and in all the subsequent steps, the apparatus for automatically performing these steps becomes complicated, and problems such as dust, scratches, dirt, etc. also occur.

The present invention has been made in view of the above points, and an object of the present invention is to provide a method of manufacturing a plastic lens by heating and compressing a plastic lens in which a molded product can be easily held and transported.

(Means and Actions for Solving the Problems) In the method for heating and compression molding a plastic lens according to the present invention, the plastic lens is molded by reheating a lens molded by injection molding and pressing with a mold. It is characterized in that reheating is performed with the sprue and runner remaining in the lens.

Further, the method is characterized in that the positioning with respect to the mold in the above method is performed through a portion other than the lens portion by leaving the sprue and the runner in the molded lens.

In the present invention, when the molded lens after the injection molding is heated and compression-molded by a mold, the molded lens is held and conveyed through a sprue and a runner remaining in the molded lens and reheated, and further, the positioning of the molded lens with respect to the mold is performed. By performing through a part other than the lens part, it is intended to simplify the work at the time of holding and transporting the molded lens and positioning the mold, and to improve the prevention of damage and contamination of the lens part,
The precision and homogeneity of this kind of plastic lens are measured.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

(First Embodiment) FIGS. 1 to 3 show a first embodiment of the present invention.
The figure is a sectional view showing the mold release process of the molded lens after injection molding.
FIG. 2 is a cross-sectional view showing a setting state of a molded lens in a mold in a compression molding step, and FIG. 3 is a cross-sectional view showing a compression molding state of a molded lens.

First, as shown in FIG. 1, a molded lens 2 having two lens portions 3 is opened through an injection molding mold 1 via a runner 5 molded by injection molding, and the molded lens 2 is projected from the mold 1. Release the sprue 4 while pinching it with your fingertips.

Thereafter, the molded lens 2 is set in a compression molding die 17 composed of the upper and lower dies 6 and 10.

As shown in FIG. 2, the compression molding die 17 is provided with lower dies 6 on both left and right sides, and on the upper side of both lower dies 6, the left and right sides which are paired with both lower dies 6. The upper die 10 is disposed so as to be movably opposed in the vertical direction.

Further, a sleeve 7 is provided on the outer periphery of the both lower dies 6 and a heating coil 9 connected to a heating source (not shown) is provided on the outer periphery of the sleeve 7 to provide heating means. ing.

Further, a notch for insertion of the runner 5 is provided at the center of the sleeve 7 so that the lens parts 3 on both left and right sides of the molded lens 2 can be inserted into the lower mold 6 on both right and left sides. A part 8 is provided.

The upper dies 10 on both the left and right sides are held by being fixed to a support member 11 connected to a linear actuator (not shown), which is a vertically moving means.

Therefore, the upper mold 10 of the compression mold 17 having the above-described configuration is used.
The molded lens 2 is set while the lens portions 3 on both the left and right sides are placed on the lower mold 6 in a state where is raised through the holding member 11.

At this time, since the runner 5 portion of the molded lens 2 is placed via the notch 8 of the sleeve 7, the setting work for the lower die 6 of the lens portion 3 is not hindered.

After the setting of the molded lens 2 with respect to the lower mold 6 of the mold 17 is completed, the upper molds 10 on the right and left sides are lowered to match the lower molds 6 on the left and right sides, respectively. , 10 are heated.

When the predetermined heating step is completed, the linear actuator of the upper mold 10 is actuated to press-mold the lens portion 3 between the upper and lower molds 6 and 10 (see FIG. 3).

Thereafter, at the time when the predetermined pressure forming step by the upper and lower dies 6, 10 is completed, the upper die 10 is raised, and the lens portion 3 after the heat molding is held in the lower die 6 while holding the sprue 4. By further releasing the mold, the molding is completed.

In the same manner, a pressure molding operation can be sequentially performed on the lens portion 3 of the molded lens 2 after the injection molding.

Also, as described above, when holding the molded lens 2 after injection molding, setting it in the mold 17 and carrying it out after pressure molding, the sprue 4 remaining in the molded lens 2 and the sprue 4 of the runner 5 are used. Thus, the required pressure molding can be performed without damaging or fouling the lens portion 3.

(Second Embodiment) FIGS. 4 to 6 show a second embodiment of the present invention.
FIG. 5 is a side sectional view showing a state in which a molded lens is set in a holder, FIG. 5 is a side sectional view showing a heating state, and FIG. 6 is a side sectional view showing a pressure molding state.

In the case of this embodiment, after the molded lens 2 is set and held in the holder 12, the molded lens 2 held via the holder 12 is heated, and the heated molded lens 2 is subjected to lens compression by the compression mold 17. The part 3 is subjected to pressure molding.

The holder 12 of the molded lens 2 is
It is configured by providing a holder main body 14 having a partial mounting portion 14a and a mounting portion 13 of the lens unit 3 having a through hole 13a of the lower die 6 on both left and right sides of the holder main body 14.
(See FIG. 4).

Further, as shown in FIG. 5, the heating device 16 includes a heating chamber 16a.
A heating coil 15 connected to a heating source (not shown) is wound around the outer periphery of the lower mold 6, and the upper and lower chambers 6 and 10 are arranged facing each other as shown in FIG. It is configured to be movably held via a pressing means (not shown).

By the way, when pressure molding the molded lens 2, first,
As shown in FIG. 4, the molded lens 2 is set on the holder 12 by placing the runner 5 portion on the placing portion 14a and placing the left and right lens portions 3 on the placing portion 13.

After that, the molded lens 2 set in the holder 12 is
The lens unit 3 is inserted into the heating chamber 16a of the heating device 16 via the holder 12, and is heated to a predetermined temperature.

After the heating, the holder 12 is positioned and held between the upper and lower dies 6 and 10 of the compression molding die 17, and then the lower dies 6 on both the left and right sides are simultaneously raised. By inserting the lens 6 into the through holes 13a on both the left and right sides of the holder 12, the lens unit 3 is placed on the lower die 6 and raised, and the lower die 6 is further raised. The part 3 is press-formed with upper and lower dies 6 and 10.

After the predetermined pressure molding, the lower die 6 is lowered, and in the lowering step of the lower die 6, the lens unit 3 mounted on the lower die 6 is mounted on the mounting portion 13 of the holder 12. By doing so, the molded lens 2 after the pressure molding is held by the holder 12.

Therefore, the molded lens 2 after pressure molding through the holder 12
Is discharged from the compression molding die 17 and the molded lens 2 is recovered from the holder 12 to complete the molding.

Further, the pressure molding operation of the molded lens 2 can be sequentially performed in the same manner.

The setting and holding of the molded lens 2 with respect to the holder 12 during the above-mentioned process and the holding at the time of unloading are performed through the sprue 4 of the molded lens 2, and the same operation and effect as in the first embodiment can be obtained. .

In particular, according to the present embodiment, since the heating and pressure molding steps of the molded lens 2 are performed through separate means, the cycle time is increased by setting the pressure means at a relatively low temperature. Has the effect of being able to shorten.

Third Embodiment FIG. 7 is a sectional view showing a third embodiment of the present invention.

In the case of the present embodiment, in the configuration of the compression mold 17 used for molding in the first embodiment, the compression mold 17 is used.
The positioning of the lens portion 3 of the molded lens 2 is previously performed on the lower die 6 by injection molding.
The elastic member 20 is formed by protruding and forming a fitting hole 19 of a projection 18 at a position corresponding to the sleeve 7 of the lower mold 6, and elastically mounting the sleeve 7 between the sleeve 7 and the lower mold 6 on the outer periphery of the lower mold 6. In that it is configured to be slidably held against the above.

Other configurations are the same as those of the compression molding die 17 of the first embodiment, and the same components are denoted by the same reference numerals and description thereof will be omitted.

When the compression molding die 17 is used to press-mold the molded lens 2 after injection molding, the sprue 4 of the molded lens 2 is held and the molded lens 2 is moved to the lower mold 6. Set inside.

At the time of such setting, a projection 18 protruding from the runner 5 of the molded lens 2 is fitted into a fitting hole 19 provided in the sleeve 7 of the lower die 6.
The positioning of the lens unit 3 with respect to the lower mold 6 can be performed by fitting the lens unit with the lower mold 6.

After setting the molded lens 2 on the lower mold 6,
When the upper die 6 is lowered, the processed surface of the upper die 6 is brought into contact with the lens portion 3 and the sleeve 7 is lowered against the elasticity of the elastic member 20 with the lowering of the upper die 6, and the lower die Heating is performed by the heating coil 9 in a pressurized state between the upper and lower dies 6 and 10 due to the elasticity of the elastic member 20 before the point, and after heating to a predetermined temperature, the upper and lower dies 6 and 10 are pressed through the pressing means of the upper die 10. Predetermined pressure molding is performed while pressing the lens portion 6 in between.

Then, after pressure molding, the upper mold 10 is raised,
The upper mold 10 is released from the lens unit 3 and the sleeve 7
Is raised by sliding the outer periphery of the lower die 6 upward by the elasticity of the elastic member 20, so that the lens portion 3 can be released from the processing surface of the lower die 6.

Similarly, the pressure molding of the molded lens 2 after the injection molding can be sequentially and continuously performed.

In the present embodiment, in addition to obtaining the same operation and effect as in the first embodiment, when the molded lens 2 is set in the compression molding die 17, 6, the positioning and setting operation can be simplified, and the lens unit 3 can be prevented from being damaged at the time of setting.

Note that the holding of the molded lens 2 in each of the above-described embodiments is shown by holding the sprue 4 with fingers in the drawings. However, instead of these, the holding by an automatic machine such as a robot hand is possible. It can facilitate work automation.

In addition, the case where the molded lens 2 after the injection molding has the lens portions 3 formed on the left and right has been described, but the number of the lens portions 3 is not limited to the number in the embodiment, and can be implemented.

(Effects of the Invention) According to the present invention, in heating and compression molding of a molded lens after injection molding, a sprue and a runner are left and used, so that the operation of loading and unloading a molded lens into and out of a compression molding die can be performed. This can be carried out while holding the lens unit, and in addition to simplifying the transport and movement system, it is possible to prevent the lens unit from being damaged or soiled.

In addition, by positioning the molded lens with respect to the compression molding die through a portion other than the lens portion, the positioning operation can be simplified and speeded up.

[Brief description of the drawings]

1 to 3 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view showing a mold releasing step of a molded lens after injection molding. FIG. 2 is a mold in a compression molding step of the molded lens. FIG. 3 is a cross-sectional view showing a state of compression molding of a molded lens, and FIGS. 4 to 6 are second views of the present invention.
FIG. 4 is a side sectional view showing a state in which a molded lens is set in a holder, FIG. 5 is a side sectional view showing a heating state, FIG. 6 is a side sectional view showing a pressure molding state, FIG. 7 is a sectional view showing a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1 ... Injection mold 2 ... Molded lens 3 ... Lens part 4 ... Sprue 5 ... Runner 6 ... Lower mold 7 ... Sleeve 8 ... Notch part 9 ... Heating coil 10 ... Top Mold 11: Holding member 12: Holder 13: Mounting portion 13a: Through hole 14: Holder body 14a: Mounting portion 15: Heating coil 16: Heating device 16a: Heating chamber 17 Compression mold 18 Projection 19 Fitting hole 20 Elastic member

Claims (2)

(57) [Claims] 1. A method for molding a plastic lens by reheating a lens molded by injection molding and pressurizing with a mold, wherein reheating is performed while the sprue and runner remain in the molded lens. Characterized by the method of hot compression molding plastic lenses. 2. A method for molding a plastic lens, wherein a lens molded by injection molding is reheated and molded by pressurizing with a mold, wherein a sprue and a runner are left in the molded lens and a part other than the lens portion of the molded lens is formed. A method of heating and compression molding a plastic lens, wherein the axis of the molded lens and the mold are aligned by positioning the portion with respect to the mold.