News Article
Heidenhain unveils high resolution vacuum encoder
Vacuum equipment is vital in the MOCVD growth of III-V semiconductors
Heidenhain is releasing its newest addition to vacuum technology with the LIP 400 series linear encoder system.
Procedures using vacuum technology have become indispensable in the electronics, analytical and medical equipment industries.
The LIP 400 series, pictured above, is compatible with high and ultra high vacuum levels in these applications, and offers a small mechanical package with options of necessary encoder electronics to be inside or outside the vacuum chamber, depending on outgassing requirements.
Outgassing is a challenge to creating and maintaining clean high-vacuum environments and outgassing products can condense onto optical elements, thermal radiators, or solar cells and obscure them.
Materials not normally considered absorbent can release enough light-weight molecules to interfere with industrial or scientific vacuum processes. Moisture, sealants, lubricants, and adhesives are the most common sources.
The rate of outgassing increases at higher temperatures because the vapour pressure and rate of chemical reaction increases. For most solid materials, the method of manufacture and preparation can reduce the level of outgassing significantly. Cleaning surfaces or baking individual components or the entire assembly before use can drive off volatile substances.
With an output signal period of 2 microns, and a measuring range of up to 420 mm, the LIP 400 linear encoder series is easily designed into motion stages. It also has an accuracy grade of either ± 1µm, or even ± 0.5 µm for those applications needing high-end metrology. The encoder system has a position stability of 2 nm and a low cyclical error (or interpolation error) of ± 20 nm.
Two different types of glass can be ordered for the scale and scanning unit reticle: a normal float glass with 8 ppm thermal growth or ZERODUR (a 0 ppm thermal growth) glass ceramic for thermal stability considerations.
The encoders are made of low outgassing materials, designed for quick pump down times, produced in a clean room environment, and shipped in a nitrogen-flushed custom packaging.
