Posted to News on 10th Sep 2010, 09:54
Linear encoders for use in high and ultra-high vacuums
Heidenhain is launching innovative linear encoders for high-vacuum and ultra-high-vacuum applications. The components used on these were adapted to the requirements of the vacuum class, particularly with respect to the housing, the printed circuit boards and the adhesives.
While the standard encoders from Heidenhain are suited for low- and medium-vacuum applications, high and ultra-high vacuums place special requirements on encoders.
Specialised design measures taken by Heidenhain to ensure the linear encoders are suitable for use in all vacuum classes include:
- Vacuum-compatible PCBs, adhesives and paints for reducing outgassing
- Vented hollow spaces to reduce the pumping time
- Laser inscription instead of labels
- Tolerance to high bake-out temperatures
- Absence of ferromagnetic materials increases process reliability
- Special vacuum cable
- Special cleaning of components and production in a clean room for utmost cleanliness
Heidenhain encoders for vacuum technology consist of a glass scale, a scanning head and the interface electronics (APE). Fixing clamps, fixed point holders, vacuum feedthrough, vacuum adhesive and extension cables are available as accessories. Widely known applications both for linear and angular encoders in a vacuum include electron microscopes, manipulators, multiple actuators, XY tables, cathode-ray microscopes, wafer inspection in the semiconductor industry, or spectrometer axes for measuring synchrotron radiation.
Vacuum technology plays a significant role in many modern production procedures and research tasks. Procedures using vacuum technology have become indispensable in the electronics industry and biotechnology, in thin-film deposition technology, in the development of new materials, and in medicine and analytical technology. The vacuum systems from Heidenhain are available in three encoder versions: LIF 481V, LIP 481V and LIP 481U. They differ essentially in accuracy, vacuum class, bake-out temperature, electrical connection and production environment.
Follow the link for more information about Heidenhain's linear encoders.
Background to vacuums
The word vacuum is used to describe an empty space, meaning a volume not filled with air or any other gas. Vacuums are classified as rough, fine, high or ultra-high, depending on the purity. The smaller the amount of air in an enclosed space (ie the lower the pressure), the higher the resulting vacuum is classified. An atmospheric pressure above 1mbar is called a rough vacuum; below 1mbar is referred to as a fine vacuum. A vacuum below 0.001mbar is a high vacuum and at 0.0000001mbar or less it is called an ultrahigh vacuum. A vacuum in the sense of enclosures free of air and therefore also of suspended particles is required wherever the presence of 'foreign particles' must be prevented. In some cases, dimensional measurements are required within the area of a vacuum, for example if very fine structures must be inspected in the submicron range or particles must be split and examined.
