Six-step precision optical centering and edging workflow, including drawing review, optical reference detection, alignment, edge machining, separate optical and mechanical verification, and cleaning.
Optical centering establishes the relationship between an optical surface or optical axis and the specified datum system. Edge diameter, mechanical runout and optical centering are related manufacturing quantities, but they are not interchangeable. A component can meet its outside-diameter tolerance and still have unacceptable optical decenter or surface tilt.
APEX configures optical-axis or center-of-curvature detection, reference alignment, controlled clamping, edge/end-face/bevel machining and final verification around the actual optical and mechanical drawing. The method is selected according to surface power, geometry, coating condition, edge thickness, datum definition and required uncertainty.
• Individual spherical lenses and precision optical elements
• Rod lenses and selected non-standard elements where the detection and holding method is applicable
• Selected cemented or assembled optics when the optical reference and clamping strategy can be defined
• Imaging, medical, camera and precision-instrument optics requiring controlled centering, tilt, edge geometry and mechanical references
• Identification of the optical reference and transfer to the machining coordinate system
• Clamping deformation, surface protection and repeatable positioning
• Simultaneous control of edge diameter, edge thickness, bevel, end face and optical centering/tilt
• Distinguishing optical centering or surface tilt from mechanical radial/axial runout
• Verification method, datum hierarchy, temperature and measurement uncertainty
Confirm the optical surfaces, centering/tilt callout, mechanical datums, outside diameter, edge thickness, bevel/chamfer and the inspection reference. Resolve any conflict between optical and mechanical definitions before setup.
Detect the optical axis, center of curvature or another agreed optical reference using the selected optical or sensor method. Establish the relationship to the machine coordinate system.
Align the component to the required optical reference and clamp it with controlled force and protected contact surfaces. Verify that the setup remains stable during machining.
Machine the edge diameter, end face, bevel or chamfer as defined. Control tool condition, feed, coolant or dry-process requirement and edge-chipping risk.
Measure centering and/or surface tilt using the agreed optical method, and verify diameter, edge thickness, bevel and mechanical runout as separate quantities. Do not use runout alone as proof of optical centering.
Clean and protect the optical surfaces and edges, record the datum/setup, measurement method, results and any coating-related handling restrictions.
• Optical-centering and precision-edging machine configuration
• Optical detection, alignment and reference-transfer modules
• Customized fixtures, protected contacts, grinding/turning tools and bevel tooling
• Inspection method, data format and acceptance-plan development
• Sample validation, FAT/SAT, training and maintenance documentation as agreed
ISO 10110-6:2025 provides the current drawing framework for centering and tilt tolerances. The project drawing should identify the relevant optical surfaces, datum system, tolerance quantity and inspection method.
Mechanical diameter, radial/axial runout, wedge, surface tilt and optical centering should be stated and measured as distinct quantities unless the design explicitly defines a validated relationship.
Acceptance should state the support and clamping condition, rotation method where used, temperature, repeated measurements, instrument status, measurement uncertainty and decision rule.
• The attainable result depends on optical power, surface geometry, aperture, edge thickness, coating condition, material, fixture and detection method. A single generic “centering accuracy” value is not transferable to every lens.
• Assemblies and cemented elements require a defined optical reference and a clamping method that does not disturb the bond or alignment. Applicability must be reviewed project by project.
• Final guarantees are confirmed on the agreed sample, drawing and inspection method in the signed technical agreement and FAT/SAT plan.
• Optical and mechanical drawings, lens prescription and datum definition
• Material, coating, diameter, thickness, edge geometry and allowable contact areas
• Centring/tilt requirement and the specified optical surfaces or axis
• Mechanical diameter, edge thickness, bevel/chamfer and runout requirements
• Available inspection method, wavelength/sensor configuration and uncertainty target
• Batch size, target cycle time, cleaning and coating-handling constraints
Q: Is low edge runout the same as good optical centering?
A: No. Mechanical runout describes movement relative to a mechanical rotation reference. Optical centering or surface tilt describes the relationship of optical surfaces or axes to the specified datum. The two can correlate in a controlled process but are not identical.
Q: Can coated lenses be centered and edged?
A: Potentially, but the coating, protected contact area, coolant compatibility, edge-chipping risk and cleaning method must be reviewed. A coated component may require dedicated soft contact and handling procedures.
Q: What information is required to quote centering accuracy?
A: The relevant optical surfaces or axis, datum system, lens geometry and power, material/coating, clamping condition, measurement method, tolerance definition and uncertainty target are required. A target number without these conditions is incomplete.
