Optical Parallels for Testing Flatness and Parallelism
Optical parallels are highly precise optical instruments designed for evaluating the flatness and parallelism of micrometer anvils. These specialized components are commonly crafted from premium optical glass or fused silica, materials chosen for their exceptional clarity, stability, and resistance to thermal expansion. Due to their critical role in precision measurement, optical parallels are manufactured to extremely stringent tolerances, ensuring minimal deviations in both flatness and parallelism. This level of accuracy is essential for maintaining the reliability and performance of micrometers used in high-precision applications.
Optical parallels are typically supplied in sets of four, with each parallel specifically designed to assess the micrometer spindle's performance at precise 90-degree rotational increments. By testing at these multiple positions, the set provides a comprehensive evaluation of the micrometer’s accuracy, detecting any inconsistencies in flatness or parallelism across different orientations. This systematic approach ensures that the micrometer operates with the highest level of precision, making optical parallels indispensable tools in quality control and metrology laboratories.
Designed for metric measurements, each parallel has a diameter of 30 mm and meets strict precision standards, with a flatness tolerance of 0.1 µm and a parallelism tolerance of 0.2 µm. These optical parallels are specifically intended for use with micrometers in the 0–25 mm range. The set includes four individual parallels: 157-101 (12.0 mm), 157-102 (12.12 mm), 157-103 (12.25 mm), and 157-104 (12.37 mm), ensuring comprehensive testing and calibration across different measurements.
Why Use Optical Parallels?
Ensuring Measurement Accuracy
Micrometers are commonly used in high-precision manufacturing and require calibration to maintain their accuracy. Optical parallels provide an effective method for verifying the flatness and alignment of micrometer anvils, reducing the risk of measurement errors. Even slight imperfections in the anvil surfaces can lead to inconsistent readings, making optical parallels an essential tool for maintaining measurement reliability.
High Precision and Stability
Optical parallels are fabricated from high-quality optical glass or fused silica, ensuring superior dimensional stability. These materials exhibit minimal thermal expansion, which is critical for maintaining precision in varying environmental conditions. The high flatness and parallelism tolerances, typically within 0.1 µm and 0.2 µm respectively, make optical parallels one of the most accurate tools available for micrometer calibration.
Non-Contact Measurement
Unlike mechanical calibration methods that may introduce wear over time, optical parallels offer a non-contact means of verifying micrometer accuracy. This ensures that there is no risk of altering or damaging the micrometer’s surfaces during inspection, preserving the integrity of both the tool and the calibration reference.
Comprehensive Calibration Approach
Optical parallels are typically supplied in sets, with each parallel designed to test the micrometer spindle at different rotational positions—usually at 90-degree increments. This approach allows for a more thorough assessment of spindle alignment and anvil flatness, ensuring that errors are identified in multiple orientations rather than just a single point of contact.
Versatility in Industrial Applications
Optical parallels are widely used across various industries, including aerospace, automotive, and precision engineering. Any application that relies on highly accurate micrometer measurements can benefit from the use of optical parallels. They are especially useful in quality control environments where ensuring compliance with tight tolerances is crucial.
