Chotest SJ5100-Prec300 High-Precision Grating-Based Length Measuring Machine for Gauge & Artifact Calibration

Overview

The Chotest SJ5100-Prec300 is a high-accuracy, contact-type length measuring machine engineered for primary and secondary calibration of dimensional artifacts and precision gauges in metrology laboratories, quality control departments, and national standards institutes. It operates on the principle of direct displacement measurement using a high-stability, long-range optical glass grating scale—certified to sub-micron linearity and thermal drift compensation—integrated with a rigid granite base and precision-ground linear motion system. Unlike interferometric or laser-based systems, this instrument employs a robust, friction-minimized mechanical probing architecture optimized for repeatability under industrial-grade environmental conditions (20 ± 2 °C). Its core function is the traceable calibration of length standards—including gauge blocks (0.1–300 mm), plug and ring gauges, thread gauges, calipers, micrometer standards, and specialized form-sensitive artifacts such as spline gauges, taper gauges, and radius templates—within a single platform. The system supports both absolute measurement (for external dimensions) and comparative measurement (for internal dimensions via master rings), delivering metrologically sound data compliant with ISO/IEC 17025 documentation requirements.

Key Features

• High-resolution optical grating scale with 0.01 µm resolution and full-travel direct reading capability across 0–340 mm
• Thermally compensated granite base structure, validated via finite element analysis for long-term geometric stability and minimal deformation under dynamic loading
• Dual-direction constant-force probing system with electronically controlled, software-selectable measuring forces (0.05 N, 0.1 N, 0.3 N, 0.5 N for internal probes; 1–10 N manually adjustable for primary probes)
• Five-axis precision worktable (ST-30.1 standard): X-axis float (±10 mm), Y-axis translation & tilt (±25 mm / ±3°), Z-axis vertical travel (0–50 mm) and rotation (±3°), enabling precise alignment to feature datums and curvature centers
• Modular probe configuration: interchangeable high-accuracy measuring caps, three-wire support plates for thread pitch diameter evaluation, and optional micro-probes for φ0.8 mm smooth ring gauges and M3 thread ring gauges
• Integrated temperature monitoring and real-time compensation algorithm aligned with ISO 1.1001-2:2022 guidelines for thermal error correction in length metrology

Sample Compatibility & Compliance

The SJ5100-Prec300 accommodates a comprehensive range of dimensional standards and production gauges. Standard configurations support calibration of gauge blocks (0.1–300 mm), smooth plug gauges (φ1–φ220 mm), smooth ring gauges (φ5–φ200 mm, wall thickness ≤50 mm), thread plug and ring gauges (M1–M220, pitch 0.25–5.5 mm), calipers (5–300 mm), micrometer calibration rods (25–300 mm), and needle gauges (φ0.1–φ10 mm). Optional modules extend capability to taper gauges, spline gauges (modulus 0.8–6 mm), gear span measurements, bearing raceway geometry, and radius templates (R5–R700 mm). All measurement procedures align with national and international metrological references including JJG 30–2012 (PRC), DIN 861 (Germany), and ASTM E1316 Annex A1 (dimensional artifact verification protocols). While not certified to ISO 17025 itself, the system’s architecture, uncertainty budgeting tools, and audit-ready reporting enable laboratories to meet ISO/IEC 17025 clause 6.4.10 (equipment traceability) and clause 7.8.2 (reporting of calibration results).

Software & Data Management

The proprietary Chotest Metrology Suite provides a Windows-based, fully localized interface (English language version available) with embedded databases of over 40 national and industrial gauge standards—including ISO, GB/T, DIN, JIS, and ANSI/ASME specifications. The software automates parameter calculation (e.g., pitch diameter for thread gauges, effective diameter for taper features), applies tolerance limits per selected standard, and generates pass/fail determinations with expanded uncertainty estimates (k=2). Measurement data are stored in a relational SQL database with full audit trail functionality—including operator ID, timestamp, environmental logs (temperature/humidity), probe selection, and force setting—supporting GLP-compliant record retention. Reports conform to ISO/IEC 17025 Annex A3 formatting requirements and export to PDF, Excel, or XML for integration into LIMS environments. Raw data and intermediate calculation steps are preserved for reanalysis, and all reports include instrument identification, calibration certificate reference, and metrological traceability statements.

Applications

This instrument serves as a foundational tool in accredited calibration laboratories performing Type A and Type B uncertainty evaluations for length standards. It is routinely deployed for: (1) periodic verification of working standards prior to use in shop-floor gage R&R studies; (2) inter-laboratory comparison exercises involving gauge block sets and thread plug gauges; (3) validation of custom non-standard gauges used in aerospace component inspection (e.g., turbine blade root profiles, fuel nozzle orifices); (4) metrological support for automotive transmission spline certification (DIN 5480/5482); and (5) academic research in dimensional metrology where reproducibility and low-hysteresis mechanical probing are critical. Its ability to measure both linear and angular deviations—via coordinated five-axis positioning—makes it uniquely suited for evaluating form errors in conical and helical artifacts without requiring separate roundness or gear-measuring equipment.

FAQ

What standards does the SJ5100-Prec300 comply with for calibration reporting?
It supports reporting structures aligned with ISO/IEC 17025, JJG 30–2012, and ASTM E1316; however, formal accreditation requires laboratory-level assessment—not instrument-level certification.
Can the system perform measurements outside the 20 ± 2 °C environment?
Operation outside this range is possible but compromises thermal error compensation; deviation beyond ±2 °C invalidates stated uncertainty budgets and requires user-applied correction models.
Is the software FDA 21 CFR Part 11 compliant?
The current release supports electronic signatures, audit trails, and role-based access control; full Part 11 compliance requires on-site validation protocol execution by the end-user laboratory.
What is the typical measurement cycle time for a standard gauge block?
From fixture loading to final report generation: ≤120 seconds for a 100 mm gauge block, including auto-alignment, multi-point sampling, and uncertainty calculation.
Does the system support automated calibration scheduling and reminder alerts?
Yes—the Metrology Suite includes configurable maintenance calendars, due-date notifications for recalibration intervals, and integration hooks for enterprise CMMS platforms via OPC UA or REST API.