CN1285270A

CN1285270A - Method for making plastic concave lens

Info

Publication number: CN1285270A
Application number: CN 99111521
Authority: CN
Inventors: 周政明
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-08-19
Filing date: 1999-08-19
Publication date: 2001-02-28

Abstract

The production method of plastic concave lens includes the following three processes of mould locking, high-pressure filling and cooling solidifying, in which the locking process is an elastic one, i,e, the central concave portion and convex portion of female mould and male mould are slightly and slowly contacted to form ring-shaped mould cavity with lens form, its high-pressure filling process utilizes high pressure to inject the molten plastics into the mould cavity, and uses air channel to discharge air and its cooling solidification process is characterized by lowering temp. of mould to make molten plastics filled in the mould cavity solidify.

Description

Method for making plastic concave lens

The invention belongs to the manufacture method of plastic products, particularly a kind of method for making plastic concave lens.

Commonly use with in the plastic cement concace mirror lens manufacturing process of ejection formation manufacturing during male and

female mould

10,11 closure states, as shown in Figure 1, after its male model 10 and the master mold 11 locked mode closures, must reserve the die cavity 12 that is the concavees lens shape in the middle of it.And the general eyeglass of producing is all circle, and because of it is concavees lens, so the thickness of its eyeglass central authorities must be than thin thickness on every side.And the running channel 14 of mould is arranged at lens edge usually, so that high-pressure plastic 13 is able to be entered and die cavity 12 is filled up by die cavity 12 edges.As shown in Figure 2, when plastics 13 are entered by running channel 14, flow characteristics according to plastics 13, it must at first be full of more runny space, it is thickness larger part around the eyeglass die cavity 12, direction shown in the figure upward arrow by pushing and be full of whole die cavity 12 to central authorities gradually around the die cavity 12, and then forms the shape of required eyeglass.Yet the reason that generally produces defective products is then in this forming process.Because plastics 13 are not before entering die cavity 12, die cavity 12 inner systems are full of air, though die cavity 12 is provided with vent port usually, can force air to be discharged by vent port when high-pressure plastic 13 enters die cavity 12.But as previously mentioned, plastics 13 are to carry out filling by the flow direction to central double team around the die cavity 12, its die cavity 12 ambient airs or can discharge via vent port, but the air of die cavity 12 central authorities, because of be subjected to from around high-pressure plastic 13 push, the situation that often has air to have little time to be contained in the plastics from the vent port effusion takes place, and, the high pressure effect forms many fine bubbles with the plastics solidification forming because of making involved air, the existence that eyeglass interior molecules after causing being shaped is formed because of bubble becomes inhomogeneous, and making its optical characteristics thereby being affected becomes defective products.Moreover because the flow direction of aforementioned plastics 13 is to enter the back by running channel 14 to be full of along die cavity 12 both sides, and join in a end away from running channel 14 porch.Therefore, if mold temperature control is improper, its plastics 13 begin to cool down when mobile and solidify, and work as the both sides stream of plastic this moment can be fashionable, plastic molecules may not produce permutation and combination again and produce the boundary joint line in intersection, also is the principal element that causes producing bad product.

The purpose of this invention is to provide a kind of method for making plastic concave lens that reduces bubble generation rate in the forming process, elimination joint line, improves product percent of pass.

The present invention includes locked mode closure, high pressure packing and cooled and solidified; The locked mode closure is the snap lock mould, and the sunk part of the outshot of the male model central authorities of its mutual closing and slightly contact and master mold central authorities contacts at first slightly, the die cavity that forms after the locked mode closure is only is the annular of lens shape peripheral part; High pressure packing system injects melt and dissolved plastics in the die cavity that the male and female mould of locked mode closure constitutes with high pressure, and with the airway exhaust; Cooled and solidified system reduces mold temperature, and the melt and dissolved plastics of filling in die cavity are solidified.

Wherein:

High pressure packing comprises initial stage filling and later stage filling;

Initial stage filling: melt and dissolved plastics are injected in the die cavity via the storing pipe, open the ventilation switch of control airway; So that air can be discharged fully along airway in the annular die cavity that locked mode constitutes when closed;

Later stage filling: after the annular die cavity that constitutes when locked mode is closed is filled up by melt and dissolved plastics, close the ventilation switch, start the oil hydraulic cylinder of storing Guan Yiduan, to plastics pressurization melt and dissolved in the storing pipe, with high pressure the melt and dissolved plastics in the storing pipe are pushed in the die cavity, and the die cavity pressure inside because of entering, melt and dissolved plastic continuing is improved, when the die cavity pressure inside is higher than the locked mode elastic force, the pressure-driven male model of the plastics that the closed ring die cavity inner high voltage that constitutes of locked mode is melt and dissolved moves towards leaving the master mold direction, the middle body of mutual closing of male model and master mold and slightly contact is separated gradually, until the pressure of the inner melt and dissolved plastics of die cavity with till the locking elastic force equates.

Owing to the present invention includes locked mode closure, high pressure packing and cooled and solidified; The locked mode closure is the snap lock mould, and the male model of its mutual closing and contact slightly gives prominence to master mold central authorities and sunk part contacts at first slightly, forms the annular die cavity of lens shape peripheral part; High pressure packing system injects melt and dissolved plastics in the die cavity with high pressure, and with the airway exhaust; Cooled and solidified system reduces mold temperature, and the melt and dissolved plastics of filling in die cavity are solidified.Still be in the filling initial stage that mutual closing contacts slightly at male model and master mold middle body, air in the die cavity discharged fully along airway, can avoid the plastics in the die cavity to comprise air, and form defective products with minimum plastics; And order ventilation switch closure is to keep the pressure in the die cavity, make plastics when high pressure packing, the pressure and the suitable displacement of male model of melt and dissolved plastics in locked mode elastic force, the die cavity, to make the interior plastics of die cavity when high pressure packing, its molecule rearranges combination forming, eliminate the generation of joint line, increase substantially the qualification rate of plastic concave lens product, thereby reach purpose of the present invention.

Fig. 1, for commonly using plastic concave lens molding die combination synoptic diagram.

Fig. 2, when commonly using plastic concave lens and be shaped plastics flow schematic diagram in die cavity.

Fig. 3, the die assembly synoptic diagram that uses for the present invention.

Fig. 4, mould ventilation switch and the air hole configuration schematic diagram used for the present invention.

Fig. 5, for implementing plastics flow schematic diagram in die cavity in the process of the present invention.

Below in conjunction with accompanying drawing the present invention is further elaborated.

As shown in Figure 3, the mould of the present invention's use comprises male model 15, formwork 17, master mold 16 and elastic body 25.Elastic body 25 can be spring or the flexible member for having identical effect.Elastic body 25 1 ends are connected with male model 15, and its other end is fixed.When locked mode was closed, male model 15 together moved as the arrow A direction with formwork 17, and applied the pressure to master mold 16 closings, made male and

female mould

15,16 constitute the elasticity locked mode.At this moment, male model 15 is with master mold 16 mutual closings and contact slightly.Because the concavees lens shape relation, the sunk part of the outshot of male model 15 central authorities and master mold 16 central authorities contacts at first slightly, so die cavity 19 is and the corresponding annular of lens shape peripheral part after its locked mode closure.Die cavity 19 inner volumes can be discharged the air in the die cavity 19 of this moment with minimum plastics 18 at the filling initial stage fully for minimum when the advantage of this kind practice was to make locked mode closed.

As shown in Figure 4, also can discharge smoothly when the plastics filling, be provided with plural airway 23 in die cavity 19 peripheries, and controlled with ventilation switch 24 for making in the die cavity 19 air.Be provided with in die cavity 19 1 sides and connect 21 the storing pipe 20 of shooting material, storing pipe 20 other ends be provided with pressurization oil hydraulic cylinder 22.During filling, melt and dissolved plastics 18 are injected in the die cavity 19 via storing pipe 20.Begin the filling initial stages when plastics 18 enter die cavity 19 by storing pipe 20, ventilation switch 24 is opening, so that air can be discharged fully along airway 23 in the die cavity 19.After die cavity 19 is filled up by plastics 18, ventilation switch 24 will be closed in good time, start the oil hydraulic cylinder 22 of storing pipe 20 1 ends, to 18 pressurizations of melt and dissolved plastics, with high pressure the melt and dissolved plastics in the storing pipe 20 18 are pushed in the die cavity 19, and die cavity 19 pressure inside because of continuing to enter, are improved in melt and dissolved plastics 18, when die cavity 19 pressure inside are higher than elastic body 25 tension force that connect male model 15, as shown in Figure 5, the pressure compresses elastomeric 25 of the melt and dissolved plastics 18 of die cavity 19 inner high voltages and drive male model 15 and move towards leaving master mold 16 directions.Because male model 15 and master mold 16 middle bodies are mutual closing and contacting slightly.When die cavity 19 has been filled up by melt and dissolved plastics 18 and under the state that melt and dissolved plastics 18 still continue to enter, male model 15 is moved towards as shown by arrow B directions, until the pressure of the inner melt and dissolved plastics 18 of die cavity 19 ' with till elastic body 25 tension force equate.Thereafter, the plastics 18 in the die cavity 19 ' begin to cool down and become complete concace mirror lens.

Stowing operation as can be known thus, male model 15 still is in the filling initial stage that mutual closing contacts slightly with master mold 16 middle bodies, with minimum plastics 18 air in the die cavity 19 is discharged fully along airway 23, therefore can avoid the plastics 18 in the die cavity 19 (19 ') to comprise air completely effectively, produce the shortcoming that contains bubble eyeglass defective products so can eliminate.Moreover, the present invention is at plastics 18 during with high pressure packing, because of the tension force of elastic body 25, the pressure and the male model 15 suitable displacements of the interior melt and dissolved plastics of die cavity 19 (19 '), to make the interior plastics 18 of die cavity 19 (19 ') when high pressure packing, its molecule rearranges combination, thereby be not easy to produce joint line, improve significantly and commonly use the easily shortcoming of the joint line eyeglass defective products of generation of manufacture method.

In sum, method for making plastic concave lens of the present invention, when the mould locked mode is closed, even male model 15 contacts slightly with master mold 16 mutual closings, make die cavity 19 volumes become minimum, and with ventilation switch 24 control airways 23 breakdown actions, make in the die cavity 19 air when plastics are done the initial stage filling, be discharged fully, can avoid the plastics 18 in the die cavity 19 (19 ') to comprise air, and the formation defective products, and order ventilation switch 24 closures are to keep the pressure in the die cavity 19 (19 '), make plastics 18 when high pressure packing, rearrange combination forming because of elastic body 25 tension force and male model 15 suitable displacements produce, eliminate the generation of joint line, increase substantially the qualification rate of plastic concave lens product.

Claims

1, a kind of method for making plastic concave lens, it comprises locked mode closure, high pressure packing and cooled and solidified; The locked mode closed system makes male and female mould closure to constitute die cavity; High pressure packing system injects melt and dissolved plastics in the die cavity that the male and female mould of locked mode closure constitutes with high pressure, and with the airway exhaust; Cooled and solidified system reduces mold temperature, and the melt and dissolved plastics of filling in die cavity are solidified; It is characterized in that described locked mode closure, its male and female mould is the elasticity locked mode, the sunk part of the outshot of the male model central authorities of the mutual closing of locked mode closure and slightly contact and master mold central authorities contacts at first slightly, the die cavity that forms after the locked mode closure is only is the annular of lens shape peripheral part.

2, method for making plastic concave lens according to claim 1 is characterized in that described high pressure packing comprises initial stage filling and later stage filling;