Accretech Rondcom GRANDE DUO / GRANDE Roundness and Cylindricity Measuring System

Overview

The Accretech Rondcom GRANDE DUO and GRANDE are high-precision rotating-table roundness and cylindricity measuring systems engineered for metrological evaluation of large-scale, heavy-duty industrial components. Operating on the workpiece-rotation principle, these instruments employ a vertically oriented, ultra-low-runout air bearing spindle to rotate the part under test while a high-resolution tactile probe traces its surface geometry in both radial (R) and axial (Z) directions. This architecture eliminates motion-induced errors associated with probe-arm rotation, ensuring traceable, NIST-aligned measurement uncertainty—critical for validating geometric tolerances in mission-critical rotating machinery. Designed specifically for applications where dimensional integrity directly impacts mechanical performance and service life, the GRANDE platform delivers sub-micron radial resolution and nanometer-level spindle stability, enabling full-form analysis of cylindrical, conical, and stepped geometries up to Ø1,500 mm and 3,000 kg.

Key Features

• Ultra-stiff air bearing main spindle with runout < 0.02 µm TIR at measurement radius—engineered for long-term thermal and mechanical stability under sustained load.
• Motorized R-axis with 0–600 mm continuous travel and 0.01 µm incremental positioning, supporting seamless transition from small-diameter shafts (e.g., precision spindles) to large-diameter rings (e.g., wind turbine main bearings).
• Dual-column granite base structure with active vibration isolation mounts, minimizing environmental perturbation and ensuring measurement repeatability across multi-hour inspection cycles.
• Integrated temperature-compensated probe system with real-time thermal drift correction, compliant with ISO 230-3 and VDI/VDE 2617 Part 6 protocols.
• Modular configuration options: GRANDE DUO (optimized for high-throughput production QA) and GRANDE (enhanced vertical height and load capacity for R&D and certification labs).

Sample Compatibility & Compliance

The GRANDE series accommodates heavy rotational components common in energy, aerospace, and machine tool sectors—including wind turbine pitch/yaw bearings, hydroelectric generator rotors, large-diameter gear blanks, and extrusion die mandrels. Its open-top design and programmable chucking interface support custom fixturing for asymmetric or non-circular reference features. All measurement algorithms and reporting outputs conform to ISO 1101 (geometrical tolerancing), ISO 12181-1/-2 (roundness), and ISO 12180-1/-2 (cylindricity), with full audit trail generation for GLP/GMP environments. Optional calibration certificate traceable to NMIJ (National Metrology Institute of Japan) satisfies ISO/IEC 17025 requirements for accredited laboratories.

Software & Data Management

Accretech’s proprietary RONDAC software provides ISO-compliant form analysis, harmonic decomposition (up to 50th order), and GD&T evaluation per ASME Y14.5–2018. Raw data is stored in vendor-neutral ASCII and CSV formats; binary project files include full metadata (operator ID, environmental logs, calibration history). The system supports FDA 21 CFR Part 11–compliant user access control, electronic signatures, and immutable audit trails. Integration with enterprise MES/QMS platforms (e.g., Siemens Opcenter, ETQ Reliance) is enabled via OPC UA and RESTful API interfaces.

Applications

• Verification of raceway roundness and waviness in >2 m diameter wind turbine main bearings—directly supporting IEC 61400-4 fatigue life modeling.
• Cylindricity assessment of large-diameter hydraulic cylinder barrels used in offshore drilling rigs, where out-of-roundness >3 µm induces seal leakage and premature wear.
• Form error mapping of precision ground rolls for cold rolling mills—enabling predictive maintenance based on harmonic amplitude trends.
• First-article inspection of aerospace landing gear axle housings, where composite roundness/cylindricity envelopes must meet Airbus ABD0100 and Boeing D6-17487 specifications.
• Calibration transfer between national metrology institutes and Tier-1 suppliers, leveraging the system’s documented measurement uncertainty budget (< 0.035 µm at k=2).

FAQ

What is the difference between GRANDE DUO and GRANDE models?

The GRANDE DUO prioritizes rapid cycle time and ease of integration into automated production lines, featuring dual-probe capability and simplified fixture mounting. The GRANDE model adds extended vertical stroke (1,200 mm), higher load capacity (3,000 kg), and optional laser interferometric Z-axis verification for metrology lab-grade certification.
Does the system support measurement of non-rotational parts such as camshafts or crankshafts?

Yes—via optional indexing rotary table and synchronized angular encoder, enabling segmented profile acquisition at defined angular intervals. Full 3D form reconstruction is supported through RONDAC’s multi-scan stitching module.
Is thermal compensation mandatory for ISO-compliant reporting?

Yes. Ambient temperature deviation >±1°C from calibration condition requires active thermal compensation using integrated Pt100 sensors and material-specific expansion coefficients. This is enforced by RONDAC’s validation workflow prior to report generation.
Can raw sensor data be exported for third-party analysis?

Yes—time-stamped analog voltage traces (probe deflection), position encoder counts, and environmental logs are exportable in HDF5 and MATLAB .mat formats without license restrictions.
What maintenance schedule is recommended for the air bearing spindle?

Annual recalibration and bearing purge verification per Accretech Technical Bulletin TB-GRANDE-07; no lubrication required. Filter replacement and compressed air quality monitoring (ISO 8573-1 Class 2:2:2) are performed quarterly.