**Name of Standard: **National standard for geometric dimensions of 3D objects

**Code designation:** ECM 113-1/19-063

**Year of publication: **2019

**Department:** dpt. 8015 ČMI LPM Praha

**Guarantor: **Ing. Jakub Sýkora

The national standard for geometric dimensions of 3D objects is used to determine the dimensions and form of spatial objects (physical bodies, products, artifacts). Dimension refers to the distance between two geometric elements in space (two points, a plane and a point, etc.). Geometric elements (points, point clouds) are measured using a sensitive touch probe in conjunction with the machine's scales and evaluation software. The measured dimension has a length unit of one meter, but is expressed in parts of this unit (millimeter, micrometer, nanometer). The length unit of one meter is defined as the distance that light travels in a vacuum in 1/299 792 458 seconds. (This definition is also given in the Metrology Act No. 505/1990 Coll.) The measurement of the dimension is carried out on the scale standards using that are built into all three axes of the machine (these are the x, y, z axes of the Cartesian coordinate system). The machine's scales, which are the unit of length, meet the continuity up to the international standard of length, as shown in the continuity scheme.

**Measuring volume:**

• Linear drives in all three axes with a measuring range of X 900 mm, Y 1500 mm, Z 630 mm

• Integrated rotary table with a range of 360°

According to information available from the manufacturer, the construction of the coordinate measuring machine ZEISS XENOS with an integrated rotary table is completely new and based on 20 years of experience of developers and customers of Carl Zeiss Industrielle Messtechnik GmbH. The machine contains several patents from Zeiss. The resolution of the rulers is comparable to the most precise measurements using laser interferometers, where a resolution of 1 nm is achieved. The well-known Abbé principle, which recommends placing the scales in the measurement axis, is solved by Zeiss's patented virtual central drive. The movement of the longest y-axis over a length of 1,500 mm is accomplished by two linear drives in the upper part of the machine. Both of these drives, which are synchronized by a new technology developed by Carl Zeiss, lead to a virtual central drive that ensures optimal distribution of drive forces depending on the position of the spindle in the transverse direction of the x-axis.

The ZEISS XENOS machine uses innovative silicon carbide ceramic for precision components. This material has not been used for comparable size components and precision before. Unlike conventional alumina ceramics, silicon carbide ceramics provide about 50% lower thermal expansion, up to 30% higher stiffness, and 20% lower weight. Compared to steel, it provides twice the stiffness with half the weight. Optimized air bearings are also important, improving stability and contributing to higher accuracy and repeatability.