Optical Parts Precision Inspection – High-Accuracy Hole Center Distance & Diameter One-Click Measurement: SIG Vision Measuring Machine Empowers Quality Upgrade

As the optical manufacturing and semiconductor packaging industries rapidly advance toward high-end, precision-driven production, dimensional accuracy requirements for optical components have become increasingly stringent. From optical lens assemblies, filters, and optical module bases to wafer substrates, a large number of optical parts contain densely distributed mounting holes, positioning pins, through-holes, blind holes, and other complex features. Traditional manual measurement methods can no longer meet the strict quality demands for hole-to-hole distance accuracy, aperture tolerances, and positional deviation in batch production.

SIG fully automatic vision measuring machine (OMM) integrates a high-resolution industrial camera, telecentric optical system, and intelligent edge-finding algorithm. With non-contact, high-efficiency, high-precision optical dimensional measurement technology, it provides a one-stop precision measurement solution for hole distance, hole diameter, and multi-hole dimension inspection of optical components.

Industry Pain Points in Hole Distance & Diameter Inspection for Optical Parts

Optical components are widely used in lens assemblies, optical communication modules, etc. Their critical features include multi-hole distribution, micro-hole diameters, and accurate center-to-center distances. For example, the lens positioning holes in a smartphone camera module or the mounting hole array on an optical module base – the relative positional accuracy of these features directly affects module assembly coaxiality and optical path alignment. If hole position deviation exceeds tolerance, it may cause assembly interference at best, or optical performance failure at worst.

Traditional inspection methods face three major bottlenecks:

• Slow caliper measurement with large errors – Hole distances on optical parts often involve center distances between multiple circular holes. Caliper measurement is not only slow but also suffers from low repeatability due to operator reading errors, making it unsuitable for batch production rhythm.
• Difficult manual focusing, inaccurate point picking – Some optical parts use highly reflective coating materials or transparent materials. Ordinary optical equipment yields low image contrast and blurred edge contours, making it easy for operators to make errors when manually picking points.
• High risk of sampling inspection, hard to trace data – Traditional manual measurement only allows limited sampling, leaving high risks of missed defects in mass production. Meanwhile, paper records cannot meet the traceability requirements of quality management systems like IATF 16949 for SPC statistical analysis.

What Key Dimensions Can Sinowon Vision Measuring Machine Measure?

SIG fully automatic vision measuring system (VMS) comprehensively covers the following critical measurement dimensions for optical components:

1. Hole Position & Distance Measurement

The equipment automatically identifies circle centers, precisely measures circle diameter, elongated slot dimensions, edge-to-hole distance, and center-to-center distance between holes, and quickly evaluates multi-hole position tolerances. For optical parts with multiple holes, it supports automatic array inspection to ensure alignment accuracy of positioning pins, mounting bases, and other structures.

2. Hole Diameter Precision Inspection

Whether it’s a micro-hole below φ0.1mm or the aperture profile of a special-shaped hole, the high-magnification optical lens and sub-pixel edge detection algorithm clearly capture hole boundary features. Repeat measurement accuracy reaches ±1.5μm, meeting the micron-level measurement requirements of optical coating components.

3. Profile & External Dimension Measurement

One-click scanning captures the overall external length, width, arc radius, angle, and fine features such as positioning grooves and bosses – no need for manual point-by-point collection.

4. Flatness & Coplanarity Measurement

For parts like optical substrates and lens mounts, flatness directly affects subsequent die bonding yield. The system uses laser-assisted autofocus and Z-axis grating feedback to quickly scan multi-point height data, automatically calculate flatness values, and output color deviation contour maps.

5. Geometric Dimensioning & Tolerancing (GD&T) Evaluation

Fully supports quantitative evaluation of parallelism, perpendicularity, position, symmetry, straightness, and other geometric tolerances, covering the main geometric dimension measurement requirements of precision optical parts.

What Core Problems Does It Solve for Optical Parts Inspection?

Problem 1: Place the part, measure everything – no manual positioning needed

Traditional vision measurement requires manual point-by-point search and confirmation, which is tedious and prone to missing measurements. SIG fully automatic video measuring system features CNC automation. Simply place the part on the worktable, and the instrument automatically scans the entire profile according to a pre-programmed path. All hole positions and diameters are output in one image – no manual point picking or repeated datum alignment.

Problem 2: Clear imaging of reflective or transparent optical elements

Coated glass, lenses, and other optical components often cause edge detection errors due to high reflectivity. Sinowon’s vision measuring machine is equipped with a programmable multi-group adjustable LED ring light and coaxial illumination system, allowing flexible adjustment of light intensity and angle to effectively eliminate coating reflection interference and significantly improve edge clarity.

Problem 3: High efficiency for mass production inspection

In fully automatic batch inspection mode, operators simply press “start”. The instrument automatically executes batch measurements along a preset path. Single-part inspection time is reduced to seconds, greatly improving inspection efficiency. Measurement data is automatically uploaded and SPC statistical analysis reports are generated, monitoring process capability in real time and helping enterprises upgrade from “sampling inspection” to “100% inspection”.

Problem 4: Non-contact non-destructive inspection, protecting precision optical surfaces

Optical coating elements and transparent parts are extremely vulnerable to physical contact damage. Sinowon’s vision measuring machine uses non-contact optical measurement principles, completely avoiding probe contact. Even for fragile parts like coated glass and thin-wall structures, non-destructive inspection is achieved.

Typical Applications

• Smartphone Lens Module – Measure lens outer diameter (±1μm repeatability), center thickness, and lens barrel mounting hole coaxiality to ensure accurate camera module focusing.
• Optical Module & Optical Communication Base – Quickly inspect mounting hole position tolerance, positioning pin diameter and height, and relative distances between features – solving the problems of slow focusing, difficult point picking, and low efficiency with traditional calipers.
• Wafer & Lead Frame – Precisely measure wafer dicing street width, chip dimensions, bond pad location, and inner/outer lead pitch and offset of lead frames.
• AR/VR Optical Elements – Perform freeform surface profile measurement and micro-structure array dimension inspection to meet the strict size accuracy requirements of novel optical designs.

As optical manufacturing moves toward higher precision and zero defects, SIG fully automatic vision measuring machine (OMM) provides stable, reproducible optical dimensional measurement capabilities. It has been deployed on production lines and in laboratories of many optical device companies. Whether for routine hole distance and aperture inspection or evaluation of flatness and other GD&T parameters, Sinowon instruments deliver reliable data assurance, helping enterprises reduce costs, increase efficiency, and improve yield.

For more optical parts inspection case studies and technical specifications, please visit Sinowon official website: www.sinowon.com to request a customized measurement solution.