Combining a highly accurate CERTO length gauge with an ND 287 digital readout equipped with statistical process control enables Heidenhain Corp. to offer a new inspection system to the market.
Since the new universal ND 287 also has a card for gauge hookup as well as other sensors, it was certain to tie-in with CERTO, an established gauge capable of a large measuring range, including nanometer-level measurement, Heidenhain says. Common applications for the system include inspection of parts with tight tolerances and gauge block calibration.
The length gauges of the Heidenhain-CERTO program measure ranges of 0-25 mm at ±0.1-µm accuracy/±0.03-µm after error compensation, and 0-60 mm at ±0.01-µm accuracy/±0.05-µm after error compensation. Error compensation is handled and stored by the ND 287 in conjunction with manual input of values from the accuracy chart included with each CERTO length gauge.
The CERTO is made up of an ultralow thermal growth material, Zerodur, for the glass scale and an invar shaft to significantly decrease thermal effects. Since a graduation and reference mark is imprinted onto the glass scale, drifting, as seen in LVDT technology, is nearly nonexistent and difficult to measure, according to Heidenhain.
When combining Heidenhain-CERTO with the new ND 287 single-axis position display with its many features designed to more fully integrate in a machine data transfer network, the system becomes an especially powerful tool, the company says. The ND 287 itself allows up to four inputs with varying interfaces and allows toggling between multiple gauges, sensors, and encoders to be done easily. The SPC function gives users the ability to write up to 10,000 measured values to an internal memory and evaluate them statistically. The stored data are output via USB or RS 232 interfaces.
With the inclusion of the company's CS-200 gauge stand with its highly polished granite surface, tight tolerances are ensured due to the well-maintained shaft perpendicularity. A vacuum chuck option, consisting of a ceramic suction plate and a diaphragm pump, is available for this system to further increase accuracy by eliminating air gaps during the metrology process.