For every factory, purchasing a CNC machine is a significant investment. To ensure the equipment becomes a core asset in production, guarantees the machining of qualified parts, and allows for cost recovery as soon as possible, it is crucial to verify the machine’s performance. Experience shows that over 80% of machines require on-site commissioning during installation to meet their technical specifications. Therefore, during the acceptance of a new machine, verification must be carried out to ensure that the machine meets its technical specifications and achieves the expected quality and efficiency from the very beginning. In addition, more than 80% of machines already in use eventually operate under abnormal or over-capacity conditions, even exceeding their designed performance limits. It is generally recommended that a new machine be re-verified after six months of use, and then annually thereafter. Periodic inspections of machine error and timely compensation for leadscrew pitch error and backlash can significantly improve machine accuracy during production, enhance the quality of machined parts, reduce scrap, and greatly improve equipment utilization. In short, timely detection of machine problems can prevent accuracy degradation and avoid damaging machine operation.
With the further adoption of CNC technology, more CNC machines are using built-in probe systems for workpiece and tool measurement, as well as digitizing contours. The realization of these functions is closely tied to the machine’s own accuracy—without regular calibration, precise execution of these functions is not feasible.
Renishaw XC-80 Laser InterferometerThe Renishaw XC-80 laser interferometer linear displacement measurement software provides data analysis based on standards such as:
2. Renishaw’s Advanced Technology
Renishaw (UK) is a global company specializing in the design and manufacture of high-precision inspection tools and systems. Its main products include probes for CMMs and CNC machines, laser interferometers, and ballbar systems. These tools support quality assurance throughout the production process: pre-process (e.g., laser and ballbar), in-process (e.g., tool and workpiece probes), and post-process (CMM inspection). Renishaw’s technologies are designed to ensure CNC accuracy, improve machine performance, and enhance manufacturing efficiency, thereby improving accuracy at the mother machine level and expanding market potential for finished products.
2.1 XC-80 Laser Interferometer
The Renishaw XC-80 laser interferometer is a high-precision device for CNC machine verification. Key features include:
The XC-80 supports automatic linear error compensation, making it easier for users to restore machine accuracy.
Applications:
2.2 QC20 Ballbar System
The QC20 ballbar and XC-80 laser interferometer are complementary tools in CNC machine verification. While the XC-80 focuses on precision measurement, the QC20 identifies the causes of machine inaccuracies and diagnoses faults. Despite its importance, the QC20 is still not widely understood compared to the XC-80.
2.2.1 What is the Ballbar?The QC20 ballbar is a tool for quickly checking 2-axis circular interpolation accuracy and diagnosing faults. It uses a high-precision displacement sensor embedded in a telescoping rod with internal coils and a moving core, operating similarly to LVDT sensors. As the rod changes length, inductance changes are translated into position signals (resolution 0.1 μm), transferred to a PC via interface. Its accuracy (±0.5 μm at 20°C) has been validated by laser interferometers.
When the machine runs a circular interpolation program, the QC20 sensor detects radius deviations. Renishaw’s software analyzes this to extract information on straightness, squareness, backlash, axis gain mismatch, and servo performance.
2.2.2 Main Functions:
2.2.3 Working Accuracy
The QC20 is a fast (10–15 minutes), convenient, and cost-effective tool to verify 2-axis performance. It can replace time-consuming NAS test part cuts and is recommended by standards such as ISO 230 and ANSI B5.54. |