Disclosure of Invention
The purpose of the invention is as follows: the invention aims to provide a lens finished product processing method for obtaining high-precision edge thickness difference without edging, and the processing method can obtain the high-precision edge thickness difference through a fine grinding processing procedure, thereby omitting the edging procedure and reducing the processing cost.
The technical scheme is as follows: the processing method of the lens finished product sequentially comprises the working procedures of milling, grinding and polishing; wherein, the fine grinding procedure comprises a processing clamp and a fine grinding die; the processing clamp is a clamp body with a cambered surface, and three grooves with the circle centers positioned on the same circumferential surface are arranged on the cambered surface of the clamp body; the fine grinding die comprises an arc-shaped groove with an open top; during processing, fixing the lens to be processed in the groove of the clamp body, and then placing the clamp body in the arc-shaped groove of the fine grinding die; according to the requirements of the finished product of the lens fine grinding, wherein the curvature radiuses of the corresponding surfaces of the lens are R1 and R2 respectively, the center thickness of the lens is D, the diameter of the lens is D, and the edge thickness difference is not more than F; assuming that the corresponding lens thickness is unchanged when the edge thickness difference is 0 and the curvature radius R value of the lens processing surface is changed, obtaining different edge thickness difference values of the lens, assuming that the corresponding curvature radius R value of the lens processing surface is unchanged when the edge thickness difference is 0 and the lens thickness is changed, obtaining different edge thickness difference values of the lens, thereby obtaining the relation between the edge thickness difference of the lens and the central thickness and the curvature radius of the processing surface; assuming that the corresponding lens thickness when the edge thickness difference is 0 and the corresponding curvature radius R value of the lens processing surface when the edge thickness difference is 0 are not changed, the lens diameter is changed on the basis of the D value, and different edge thickness difference values of the lens are obtained; thereby obtaining the relation between the diameter of the lens and the thickness difference of the edge; based on the relationship, the corresponding edge thickness difference values of the curvature radius R value of the lens processing surface, the lens center thickness D and the lens diameter D in the allowable tolerance range are obtained, and the finished lens product with the edge thickness difference not more than F is obtained by processing the curvature radius R value of the lens processing surface, the lens center thickness D and the lens diameter D to a certain value in the tolerance range.
Wherein, when processing the different faces of lens, the processing anchor clamps that correspond are different, and when processing the first face of lens, the concave surface is the plane in the recess of the processing anchor clamps I that correspond, and when processing the lens second face, the concave surface is the cambered surface in the recess of the processing anchor clamps II that correspond.
Wherein, all be equipped with plastics annular ring in the three recess, the annular ring passes through glue to be fixed on the inside wall of recess. The annular ring has a blocking effect on the edge of the lens, so that the lens is limited to move in the front, back, left and right directions, the annular ring is good in wear resistance, and the lens can be limited in the groove, namely the annular ring is used for fixing the lens placed in the groove of the clamp body.
The depth of the three grooves is consistent, and the depth of the grooves is based on the arc-shaped curved surface of the processing clamp.
Wherein, the curvature of the arc-shaped working surface of the fine grinding die is consistent with the curvature of the corresponding surface of the fine grinding finished product.
The processing method of the lens finished product comprises the following steps of:
(1) reversely deducing the requirements of the fine-ground finished product on the center thickness, the curvature radius and the edge thickness difference of the lens based on the requirements of the finished product on the center thickness, the curvature radius and the edge thickness difference of the lens; designing size parameters of a corresponding processing clamp based on the requirements of the center thickness, the curvature radius and the edge thickness difference of the corresponding surface of the lens of the finished product of accurate grinding, wherein the size parameters comprise the curvature of the cambered surface of the processing clamp, the size of a groove and the arrangement relation of the groove;
(2) and (3) processing the curvature of the arc surface of the clamp: during processing, a cushion skin is placed in the groove; the curvature radius R3+ the thickness of the cushion skin of the arc surface of the clamp body is equal to the curvature radius R1 or R2 of the corresponding surface of the lens fine grinding finished product (the curvature value of the surface to be processed of the lens is determined, and the curvature of the surface to be processed of the lens and the curvature of the clamp body are based on a circle center, namely the arc surface of the clamp body and the arc surface of the surface to be processed are concentric circles after the processing is finished); the size of the groove: the inner diameter of the groove is the sum of the diameter of the lens and the thickness of the annular ring; the arrangement relation of the grooves is as follows: the three grooves are uniformly distributed on the arc surface of the clamp body, and the included angles between the center lines of the three grooves and the center line of the clamp body are equal; the adjacent parts of the three uniformly distributed grooves on the clamp body must have certain spaced minimum distances so that the edges of three lenses placed in the grooves of the clamp body cannot touch, at the moment, the adjacent edges of three annular rings placed in the grooves of the clamp body cannot touch, and meanwhile, the wall thickness formed by the distance between the adjacent parts of the three grooves on the clamp body also needs to ensure the strength of the wall;
(3) processing a first surface of a lens, respectively placing three lenses in three grooves of a processing clamp I, pressing the processing clamp I with a lens blank on a fine grinding die by a pressure head of a lower pendulum machine, adjusting the curvature of an arc-shaped working surface of the fine grinding die based on the curvature requirement of a corresponding surface of a fine grinding finished product, and passively rotating the processing clamp I under the driving of the fine grinding die rotating at a high speed;
(4) processing one surface of the lens to obtain a fine grinding semi-finished product, processing the other surface of the lens, respectively placing three fine grinding semi-finished products in three grooves of a processing clamp II, pressing the processing clamp II with the fine grinding semi-finished product on a fine grinding mold by a pressure head of a lower pendulum machine, adjusting the curvature of an arc-shaped working surface of the fine grinding mold based on the curvature requirement of the corresponding surface of the fine grinding finished product, and passively rotating the processing clamp II under the driving of the fine grinding mold rotating at a high speed; and obtaining a fine grinding finished product.
In the step (3) and the step (4), the pressure applied to the processing clamp is 0.5-10 kg, and the rotation speed of the fine grinding die is 800-3500 rpm.
Wherein, in the step (3) and the step (4), the diameter ratio of the diameter of the fine grinding die to the diameter of the processing clamp is 1.5: 1.
in the step (3) and the step (4), the curvature of the arc-shaped working surface in the accurate grinding die is determined based on the curvature of the corresponding surface of the accurate grinding finished product, the accurate grinding die with the corresponding curvature is adopted to process the workpiece for 3-5 s, the processing is stopped, the lens is taken out, the curvature of the processing surface of the lens is measured, if the requirement is met, the next step is carried out, if the requirement is not met, the curvature of the arc-shaped working surface of the accurate grinding die is trimmed by adopting the arc-shaped working surface of the trimming die, the curvature of the arc-shaped working surface of the trimming die is the same as the curvature of the corresponding surface of the accurate grinding finished product, and the caliber of the arc-shaped working surface of the trimming die is larger than the caliber of the arc-shaped working surface of the accurate grinding die
During processing, the thickness of the lens is adjusted based on the finish grinding time control, and the curvature radius of the corresponding surface of the lens is controlled based on the curvature radius of the finish grinding die. The handle of the accurate grinding die is fixed to a machine spindle through a jig, the lens blank is placed on the machining clamp, then the machining clamp is placed on the arc-shaped working face of the accurate grinding die, machine parameters are adjusted, machining is started, the machine is started, the automatic guide pipe can spray liquid onto the arc-shaped working face of the accurate grinding die, and cutting action is generated through relative motion of the high-speed rotating accurate grinding die and the passively rotating lens blank machining face, so that the machining requirement of the corresponding cambered surface of the lens is obtained.
Has the advantages that: compared with the prior art, the invention has the remarkable advantages that: according to the method, the edge thickness difference of the lens is accurately controlled in the fine grinding process, so that the requirement of the high-precision edge thickness difference of a finished lens product is met, the edge grinding process is omitted, and the cost is greatly reduced; meanwhile, in the fine grinding processing procedure, a plurality of lens blanks can be processed at one time, the processing output is doubled, and the processing efficiency is greatly improved; finally, the radius and thickness of the lens are changed less frequently than those of the lens machined by a single lens in the process of finely grinding the plurality of lenses, and the repair is simpler.
Detailed Description
As shown in fig. 1 to 9, the processing method of the lens finished product of the present invention sequentially includes the steps of milling, fine grinding and polishing; wherein, the fine grinding process comprises a processing clamp and a fine grinding die 9; the machining clamp is a clamp body 11 with an arc surface, three grooves 10 with the circle centers positioned on the same circumferential surface are arranged on the arc surface of the clamp body 11, included angles between center lines of the three grooves and the center line of the clamp body are equal, the fine grinding mold 9 comprises an arc-shaped groove 4 with an opening at the top, and the fine grinding mold 9 further comprises a handle 5 fixedly connected with an external rotating shaft; during processing, the lens 100 to be processed is fixed in the groove 10 of the clamp body 11, and then the clamp body 11 is placed in the arc-shaped groove 4 of the fine grinding mold 9; according to the requirements of the finished product of the lens fine grinding, wherein the curvature radiuses of the corresponding surfaces of the lens are R1 and R2 respectively, the center thickness of the lens is D, the diameter of the lens is D, and the edge thickness difference is not more than F; assuming that the corresponding lens thickness is unchanged when the edge thickness difference is 0, and the curvature radius R value of the lens processing surface is changed based on the corresponding curvature radius when the corresponding edge thickness difference is 0, obtaining different edge thickness difference values of the lens, assuming that the corresponding curvature radius R value of the lens processing surface is unchanged when the edge thickness difference is 0, and the lens thickness is changed based on the corresponding lens thickness when the corresponding edge thickness difference is 0, obtaining different edge thickness difference values of the lens, thereby obtaining the relation between the edge thickness difference of the lens and the center thickness as well as the curvature radius of the processing surface; assuming that the corresponding lens thickness when the edge thickness difference is 0 and the corresponding curvature radius R value of the lens processing surface when the edge thickness difference is 0 are not changed, the lens diameter is changed on the basis of the D value, and different edge thickness difference values of the lens are obtained; thereby obtaining the relation between the diameter of the lens and the thickness difference of the edge; based on the relationship, the corresponding edge thickness difference values of the curvature radius R value of the lens processing surface, the lens center thickness D and the lens diameter D in the allowable tolerance range are obtained, and the finished lens product with the edge thickness difference not more than F is obtained by processing the curvature radius R value of the lens processing surface, the lens center thickness D and the lens diameter D to a certain value in the tolerance range.
The influence of the tolerance of the lens diameter on the edge thickness difference of the lens is an independent factor, and cannot be changed by the change of the central thickness and the curvature of the lens, but the edge thickness difference in a certain direction can be generated, and the edge thickness difference and the lens have different thicknesses, and different edge thickness differences generated by the aperture can generate mutual offset effect, so that the edge thickness difference value of the lens is obtained.
When processing the different planes of lens, corresponding processing anchor clamps are different, and when processing the first face of lens, concave surface 7 in the recess of corresponding processing anchor clamps I1 is the plane, and when processing the second face of lens, concave surface 6 in the recess of corresponding processing anchor clamps II8 is the cambered surface. The concave surface 7 is a plane groove 10 for placing the lens 100, the concave surface 6 of the processing clamp II corresponding to the groove is a cambered surface, and the concave surface 6 is a cambered surface groove 10 for placing the refined semi-finished product 90 of which one surface is refined.
The processing clamp is made of metal or plastic and is provided with a spherical segment cambered surface, the top of the processing clamp is provided with a plurality of grooves, the circle centers of the grooves are uniformly distributed on the arc-shaped surface, the curvature surfaces of the grooves are consistent with the curvature surfaces of the segments, and the distribution uniformity of the three grooves is ensured.
Wherein, be equipped with plastics annular ring 2 in the recess 10, annular ring 2 passes through glue to be fixed on the inside wall of recess 10. The annular ring 2 has a blocking effect on the edge of the lens in the groove, so that the lens is limited to move in the front, back, left and right directions, the annular ring 2 is good in wear resistance, and the lens can be limited in the groove 10, namely the annular ring 2 is used for fixing the lens placed in the groove 10 of the clamp body 11. The depths of the three grooves 10 are consistent, and the depths of the grooves 10 are based on the arc-shaped curved surface of the processing clamp. During processing, place pad skin 3 in the recess 10, the camber face of lens relies on and realizes gluing each other with 3 faces of pad skin in the anchor clamps body recess 10 have elasticity, realizes the injecing to lens upper and lower direction to through the injecing of annular ring 2 to lens all around, left and right sides direction, and then fix lens and can not remove in the recess. The outer diameter of the cushion skin 3 is slightly smaller than the inner diameter of the groove 10, and the cushion skin 3 is directly placed in the groove 10.
The refining process also comprises at least one refining die 9, and the curvature of the arc-shaped working surface 4 of the refining die 9 is consistent with that of the corresponding surface of the refined finished product. The arc-shaped working surface 4 of the fine grinding die 9 is made of metal materials, and a diamond layer is paved on the arc-shaped working surface 4.
During processing, the thickness of the lens is adjusted based on the finish grinding time control, and the curvature radius of the corresponding surface of the lens is controlled based on the curvature radius of the finish grinding die. Fix the handle 5 of correct grinding mould 9 to the machine main shaft through the tool, place the lens blank on processing anchor clamps, then will process on anchor clamps place the arc working face 4 of correct grinding mould 9, adjust the machine parameter, start machine processing, machine start can automatic pipe jet liquid to correct grinding mould 9 arc working face 4 on, through the relative motion of the correct grinding mould 9 of high-speed rotation and the lens working face of passive rotation, produce the cutting action, obtain the processing requirement of the corresponding cambered surface of lens blank.
The invention relates to a processing method of a lens finished product, wherein the accurate grinding process specifically comprises the following steps:
step 1, firstly determining parameters of processing the second surface of the lens (also parameters of a finished product of the lens by accurate grinding):
(1.1) determining the requirement of the fine grinding finished product of the lens fine grinding procedure according to the finished product drawing of the lens polishing and the machining allowance requirement of the polishing procedure: 21.0219 for R1, 21.0219 for R2, lens diameter
The center thickness d is 2.015mm, the edge thickness difference is not more than 0.0038mm, the concrete shape is shown in figure 10;
(1.2) assuming that the corresponding thickness is 2mm when the lens thickness is 0, the radius of curvature R2 of the lens processing surface is changed in an incremental manner on the basis of the R value 21 when the corresponding side thickness difference is 0 to obtain different side thickness difference values, see table 4, assuming that the radius of curvature R of the lens processing surface is 21, the corresponding radius of curvature when the corresponding side thickness difference is 0, the lens thickness is changed in an incremental manner on the basis of 2mm of the d value to obtain different side thickness difference values, see table 3; assuming that the central thickness is 2.15mm and the curvature radius R value of the lens processing surface is 21 unchanged, the diameter of the lens is changed in an increasing or decreasing manner on the basis of 8mm, and different edge thickness difference values of the lens are obtained, see Table 5;
(1.3) according to the thickness requirement, looking up a table 3, wherein when the allowable tolerance range of the thickness 2.015 is 0.005, the corresponding thicknesses are 2.01, 2.015 and 2.02, and the edge thickness differences corresponding to the thicknesses of 2.01, 2.015 and 2.02 are +0.0016, +0.0024 and + 0.0032;
(1.4) looking up table 4 (table 4 shows the change of the edge thickness difference when the thickness is constant and R2 is changed) according to the requirement of the lens processing surface R2, wherein the R values corresponding to the tolerance 0.0044 of R2 ═ 21.0219 are 21.0262, 21.0219 and 21.0175, and the edge thickness differences corresponding to the R values 21.0262, 21.0219 and 21.0175 are-0.0054, -0.0045 and-0.0036;
(1.5) according to the diameter requirement of lens processing, looking up a table 5, wherein the diameters of 8mm are 7.99mm, 8mm and 8.01mm when the allowable tolerance is 0.01, and the edge thickness differences of 7.99mm, 8mm and 8.01mm are +0.0019mm, 0mm and +0.0019 mm;
(1.6) the relationship among the center thickness, the R1 value and the diameter corresponding to the edge thickness difference is an addition-subtraction relationship, the maximum value of the edge thickness difference is obtained by arbitrary addition-subtraction of the three, and the maximum value of the edge thickness difference is a key index of processing the lens, namely +0.0016+ 0.00-0.0054-0.0038, and the quality of the constraint quality is generated by the maximum value of the edge thickness difference; directly using a plus sign to indicate the direction of the edge thickness difference in the list;
(1.7) setting parameters of a processing machine: the rotating speed is 1800 rpm, the pressure loaded on the processing clamp is 1 kg, and the processing time is 20 seconds;
step 2, determining the processing parameters of the first surface of the lens:
(2.1) determining the requirements of the fine-grinding semi-finished product of the lens fine-grinding process according to the requirements of the fine-grinding finished product diagram of the lens: 21.0219 for R1, 21.0219 for R2, lens diameter
Center thickness of 2.165mm and edge thickness differenceNo more than 0.0038mm, and the specific shape is shown in FIG. 11;
(2.2) assuming that the corresponding thickness is 2.15mm when the lens thickness is 0 and the radius of curvature R1 of the lens processing surface is changed gradually on the basis of the R value 21 when the corresponding side thickness difference is 0 to obtain different side thickness difference values, see table 2, assuming that the radius of curvature R of the lens processing surface is 21 and is not changed, and the corresponding radius of curvature when the corresponding side thickness difference is 0, the lens thickness is changed gradually on the basis of 2.15mm of the d value to obtain different side thickness difference values, see table 1; assuming that the central thickness is 2.15mm and the curvature radius R value of the lens processing surface is 21 unchanged, the diameter of the lens is changed in an increasing or decreasing manner on the basis of 8mm, and different edge thickness difference values of the lens are obtained, see Table 5;
(2.3) according to the thickness requirement, looking up a table 1, wherein when the allowable tolerance range of the thickness 2.165 is 0.005, the corresponding thicknesses are 2.16, 2.165 and 2.17, and the edge thickness differences corresponding to the thicknesses of 2.16, 2.165 and 2.17 are +0.0016, +0.0024 and + 0.0032;
(2.4) according to the requirement of the lens processing surface R1, looking up table 2 (table 2 shows the change of the edge thickness difference when the thickness is constant and R1 is changed), wherein the R values corresponding to the tolerance 0.0044 of R1 ═ 21.0219 are 21.0262, 21.0219 and 21.0175, and the edge thickness differences corresponding to the R values 21.0262, 21.0219 and 21.0175 are-0.0054, -0.0045 and-0.0036;
(2.5) according to the diameter requirement of lens processing, looking up a table 5, wherein the diameters of 8mm are 7.99mm, 8mm and 8.01mm when the allowable tolerance is 0.01, and the edge thickness differences of 7.99mm, 8mm and 8.01mm are +0.0019mm, 0mm and +0.0019 mm;
(2.6) the relationship among the center thickness, the R1 value and the diameter corresponding to the edge thickness difference is plus-minus relationship, and the maximum value of the edge thickness difference is obtained by arbitrarily adding and subtracting the three values, and is a key index for processing the lens, namely, the maximum value of the edge thickness difference is +0.0016+ 0.00-0.0054-0.0038; directly using a plus sign to indicate the direction of the edge thickness difference in the list;
(2.7) setting parameters of a processing machine: the rotating speed is 1800 rpm, the pressure loaded on the processing clamp II8 is 1 kg, and the processing time is 20 seconds; the edge thickness difference key parameter of the finished lens product is determined by calculating when the second surface is processed, namely the parameters of the finished lens product are that R is 21, the tolerance is 0.0044, and the center thickness is: 2.015mm, the tolerance is 0.005, and the maximum edge thickness difference is 0.0038 mm;
step 3, determining the parameters of the lens blank: the diameter is 8mm, the tolerance is 0.01, the thickness is 2.3mm, the tolerance is 0.005, and the specific shape is shown in figure 12;
step 4, reversely designing a processing clamp II according to the specific parameters of the finished lens (refined finished product 80) in the step 1, wherein the processing clamp II8 provided with the finished lens (refined semi-finished product 90) is shown in FIG. 4; in the processing clamp II8, the included angle between the central line of the groove 10 and the central line of the clamp body 11 is 17 degrees;
and 5, reversely designing a processing clamp I1 according to the specific parameters of the finished lens (one surface of the finished lens) in the step 2, wherein the processing clamp I1 provided with the lens blank 100 is shown in FIG. 1, and in the processing clamp I1, the included angle between the central line of the groove 10 and the central line of the clamp body 11 is 17 degrees.
The fine grinding finished product obtained by the method can not only realize that the size of the lens meets the processing precision requirement, but also enable the edge thickness difference to reach a high precision target.
Wherein, table 1 shows the change of the edge thickness difference when the thickness is changed without changing R1:
table 2 shows the edge thickness difference when R1 was changed without changing the thickness:
table 3 shows the variation of the edge thickness difference when the thickness is changed without changing R2:
table 4 shows the variation of the edge thickness difference when the R value is changed without changing the thickness:
table 5 shows the relationship between the thickness, R value and the difference between the diameter and the edge thickness: