Chotest SJ6000 High-Precision Single-Frequency Laser Interferometer
| Brand | Chotest |
|---|---|
| Origin | Guangdong, China |
| Model | SJ6000 |
| Linear Measurement Range | 80 m |
| Linear Measurement Accuracy | ±0.5 ppm |
| Linear Resolution | 1 nm |
| Angular Measurement Accuracy | (0.02%R + 0.1 + 0.024M) arcsec |
| Frequency Stabilization Accuracy | ±0.05 ppm |
| Warm-up Time | ≤ 6 min |
| Light Source | Single-Frequency He-Ne Laser |
| Environmental Compensation | Integrated ECU Unit (air temperature, material temperature, pressure, humidity) |
| Maximum Dynamic Measurement Speed | 4 m/s |
| Supported Geometric Error Measurements | Straightness, Flatness, Squareness, Pitch, Yaw, Roll, Perpendicularity, Runout |
| Data Output | CNC-compatible error compensation files, ISO-compliant calibration reports with full audit trail |
Overview
The Chotest SJ6000 High-Precision Single-Frequency Laser Interferometer is a metrology-grade displacement measurement system engineered for traceable, nanometer-level linear and angular characterization of machine tools, coordinate measuring machines (CMMs), and precision motion platforms. It operates on the fundamental principle of optical interference—comparing the phase difference between a reference beam and a measurement beam derived from a thermally stabilized single-frequency He-Ne laser. With a frequency stabilization accuracy of ±0.05 ppm and a linear measurement accuracy of ±0.5 ppm over 80 meters, the SJ6000 meets the stringent requirements of ISO 230-2 (machine tool testing), ISO 10360 (CMM verification), and GB/T 17421.2 (Chinese national standard for geometric accuracy evaluation). Its design prioritizes in-situ deployment: minimal warm-up time (≤6 minutes), robust immunity to electromagnetic interference via shielded laser head and isolated power architecture, and compatibility with industrial shop-floor environments (10–35 °C, 20–80% RH).
Key Features
- Nanometer-resolution linear displacement measurement (1 nm resolution) enabled by high-stability single-frequency laser source and quadrature detection electronics.
- Integrated Environmental Compensation Unit (ECU) that continuously monitors air temperature, material temperature, barometric pressure, and relative humidity to dynamically correct laser wavelength drift per ISO 230-3 Annex A.
- Dynamic measurement capability up to 4 m/s, supporting real-time acquisition of position, velocity, acceleration, and vibration amplitude during machine motion—critical for servo tuning and mechanical resonance analysis.
- Modular optical configuration enabling comprehensive geometric error mapping: straightness (horizontal/vertical), angular errors (pitch/yaw/roll), perpendicularity, squareness, and rotary axis runout using retroreflector-based or heterodyne-capable accessories.
- Direct CNC integration: generates industry-standard error compensation tables (e.g., Siemens SINUMERIK, Heidenhain TNC, Fanuc FOCAS) compliant with ISO 230-6 for automatic feed-forward correction.
- Full audit-trail calibration reporting aligned with GLP/GMP documentation requirements, including timestamped environmental logs, raw interferometric data, uncertainty budgets, and operator metadata.
Sample Compatibility & Compliance
The SJ6000 is designed for non-contact, absolute measurement of reflective or retroreflector-equipped surfaces on metal, ceramic, and composite components. It interfaces seamlessly with CNC machining centers (including large-format gantry mills >2 m span), bridge-type and horizontal-arm CMMs, laser trackers, grating-based length standards, and automated vision inspection systems. All measurement protocols conform to international standards including ISO 230 series (machine tool performance evaluation), ISO 10360 (CMM acceptance and reverification), ISO 16015 (uncertainty evaluation for dimensional measurements), and JJF 1094 (Chinese metrological verification regulation for laser interferometers). The system supports traceability to national standards via documented calibration certificates issued by CNAS-accredited laboratories.
Software & Data Management
The proprietary Chotest Metrology Suite provides a Windows-based interface for test plan definition, real-time data visualization, geometric error synthesis, and report generation. Software features include automated sequence scripting for multi-axis error mapping, FFT-based vibration spectrum analysis, thermal drift modeling using ECU inputs, and export of compensation files in native CNC formats. Data integrity is ensured through password-protected user roles, electronic signatures, and immutable storage of raw interferogram datasets. The software complies with FDA 21 CFR Part 11 requirements for electronic records and signatures when configured with audit-log archiving and access control policies.
Applications
- Machine tool volumetric error mapping and volumetric compensation for 5-axis machining centers used in electric motor rotor housing and gearbox casing production.
- In-process verification of large-format battery tray flatness and sealing surface geometry on die-casting machines and post-machining milling lines.
- Dynamic performance validation of high-speed spindles (up to 20,000 rpm), including synchronous error motion analysis for NVH-sensitive e-motor shafts.
- Periodic verification and recalibration of CMMs, optical comparators, and automated optical inspection (AOI) systems in Tier-1 automotive suppliers’ quality labs.
- Validation of encoder linearity and scale error in linear motors and precision stages deployed in semiconductor packaging and EV battery module assembly equipment.
FAQ
What standards does the SJ6000 comply with for machine tool calibration?
The SJ6000 implements measurement procedures and uncertainty evaluation methods fully aligned with ISO 230-2 (positioning accuracy), ISO 230-6 (volumetric performance), and ISO 10360-2 (CMM probing error assessment). Calibration certificates are traceable to NIM (National Institute of Metrology, China) or other BIPM-affiliated NMIs.
Can the SJ6000 operate without climate-controlled lab conditions?
Yes—the integrated ECU unit enables reliable operation across ambient temperatures from 10 °C to 35 °C and humidity levels from 20% to 80% RH, satisfying ISO 230-3 environmental classification Class II (shop-floor use).
How is measurement uncertainty quantified for linear displacement?
Combined standard uncertainty includes contributions from laser wavelength stability (±0.05 ppm), refractive index correction (ECU-derived), alignment error, cosine error, Abbe error, and electronic interpolation noise—typically <0.7 ppm at 80 m under controlled conditions.
Does the system support automated error compensation file generation for CNC controllers?
Yes—software exports standardized compensation tables compatible with major CNC platforms (Siemens, Heidenhain, Fanuc, Mitsubishi), including support for bidirectional backlash compensation and spatial error mapping per ISO 230-6 Annex D.
What is the maximum distance for angular measurements using the SJ6000?
Angular measurements (pitch/yaw) are supported up to 30 m baseline using the included autocollimator attachment; straightness and perpendicularity measurements extend to full 80 m linear range with appropriate optics and mounting fixtures.
