What is the processing flow of Shi Ying glass lenses?

Shi Ying glass lens complete processing process.

Shi Ying has high hardness, high brittleness and high temperature resistance. The processing is divided into the whole process of blank forming → rough grinding → fine grinding → polishing → film cleaning → detection and cutting, and it is divided into two process routes: flat window, spherical lens and aspherical lens.

1. Preparation of raw materials and blanks

Raw material screening

High-purity fused Shi Ying rod/Shi Ying plate (JGS1 deep ultraviolet, JGS2 ultraviolet and JGS3 infrared) is selected to eliminate bubbles, stones, stripes and interlayer defects.

Cutting and cutting

Big board: diamond saw blade cuts square blank;

Bar: the cylindrical material is cut by the internal cutter;

It is required to leave a machining allowance of 0.3 ~ 1 mm to avoid edge collapse.

Rounding/milling profile (for lens)

The cylindrical blank is put on a rounding machine, and the excircle is milled to the standard outer diameter to ensure coaxiality; The flat window skips this step.

Annealing stress relief

After cutting, there is stress inside, and it is put into an annealing furnace for slow cooling at a constant temperature of 800 ~ 1100℃ to prevent subsequent grinding and polishing from cracking.

Second, the rough grinding process (removing allowance and forming curvature)

1. Rough grinding of plane Shi Ying window.

1) Double-sided grinding machine, cast iron grinding disc+diamond abrasive (240 # ~ 600 #);

2) quickly milling off the cutting knife lines and unevenness, and controlling the parallelism and thickness allowance by 0.05～0.15mm；;

2. Rough grinding of spherical lens

1) a spherical milling machine, in which the convex/concave standard curvature r is directly milled by a diamond forming grinding wheel;

2) after one side is formed, the other side is turned over to ensure the center thickness;

3) After rough grinding, the surface is frosted and foggy, eliminating the big defects of the blank.

Third, the fine grinding process (improving the surface accuracy and reducing the pits)

After rough grinding, there are deep scratches on the surface, and it enters fine grinding:

The grinding disc is changed into a resin copper disc, and 800 # ~ 3000 # diamond micropowder;

Double-sided fine grinding (plain film) and single spherical fine grinding (lens);

Control indicators:

The surface accuracy is up to standard initially;

The depth of surface pits is reduced to micron level, and the polishing margin is only 0.01 ~ 0.03 mm;

Chamfering: the four corners of the diamond grinding wheel are inverted by C angle/R angle to prevent edge collapse in subsequent processes.

Fourth, the polishing process (core, to achieve an optically transparent mirror)

1. Polishing the plane Shi Ying window.

Polishing mold: polyurethane polishing skin+colloidal silica slurry (cerium oxide/silica sol);

Double-sided polishing machine throws at a uniform speed to remove fine grinding lines;

Completion requirements: no scratches, no pits and even light transmission.

2. Spherical lens polishing

1) Spherical polishing machine, asphalt polishing mold with curvature;

2) low-speed polishing, real-time monitoring of curvature radius, center deviation and aperture;

3) Aspheric Shi Ying lens: CNC aspheric polishing machine is used to correct the surface shape point by point, and the accuracy can be less than 0.1μm m..

Polishing key quality control

Aperture number, local aperture, surface defects and smoothness (national standard I/II).

V. Intermediate ultrasonic cleaning

After polishing, a large amount of polishing powder remains on the surface and side, which must be cleaned and recoated;

Multi-tank ultrasonic cleaning: pure water+neutral cleaning agent → alkaline cleaning → pure water multi-stage rinsing;

Hot air drying/vacuum drying;

Store in clean room to prevent fingerprint and dust pollution.

Six, coating process (optional as needed, UV/laser lens must be done)

Plating functional film according to the usage scene:

Anti-reflection film AR: ultraviolet 355/266nm, 193nm deep ultraviolet, 1064nm infrared, reducing reflection and improving light transmission;

High reflection film HR: laser resonator reflector;

Spectral film, polarizing film, protective hard film;

Processing equipment: vacuum ion plating machine, electron beam evaporation machine, 10,000/1,000 class clean workshop operation.

Seven, post-processing precision machining (high-end lens selection)

Machining of center hole/countersunk hole: diamond micro-hole drill for assembly and fixation;

Slotting and step milling: special-shaped window, flange Shi Ying mirror;

Laser marking: model, specification and band identification;

Eight, all optical detection (finished product screening)

Appearance: 40 times microscope to check scratches, pits, edge collapse, stones;

Size: micrometer to measure thickness, outer diameter and center thickness;

Surface type: laser interferometer measuring aperture and surface shape accuracy PV/RMS；;

Optical properties: transmittance/reflectivity measured by spectrophotometer;

Parallelism, eccentricity and radius of curvature detection;

Unqualified products are reworked, polished or scrapped.

Nine, clean packaging warehousing

Dust-free cloth wiping, nitrogen purging, vacuum bag/optical box independent packaging, moisture-proof and dustproof.

Simplified version of short process (easy to remember)

Raw material cutting → annealing to relieve stress → rough grinding and forming → fine grinding and surface modification → chamfering → precision polishing → ultrasonic cleaning → vacuum coating → secondary fine cleaning → optical inspection → packaging.

Complement the process differences between the two types of products

Shi Ying plane window: no rounding, no spherical milling, only double-sided grinding and polishing, short process;

Shi Ying Spherical/Aspheric Lens: Add rounding, spherical milling and grinding, spherical polishing and eccentricity detection, with longer process and higher accuracy requirements.