2010-2011. Technology for automated large shaped sapphire crystals growing.
Rostox-N successfully completed the R&D project for the developing a technology for automated growing of large scale shaped sapphire crystals in form of ribbons (160-250 mm wide, 5-15 mm thick and up to 500 mm long) and tubes (dia. 50-100 mm and up to 500 mm long).
2007-2009. Development of automated equipment for growing large shaped sapphire and refractory oxide crystals.
Rostox-N jointly with EZAN successfully completed the R&D project for the brand new generation of high-efficient and cost-effective EFG/Stepanov puller, High stability 100 kW IGBT medium frequency converter, and Adaptive (self-adjusting) system for automatic process control.
Crystal Growing Unit
- Melting temperature: up to 2200Î Ñ
- Crucible diameter: up to 250 mm
- Crystal weight: up to 5 / 10 kg
- Weight sensor range: up to 5 / 10 kg
- Weight sensor sensitivity: min 0.02 / 0.04 g
- Inert gas pressure in chamber: max. 1,5x105Pa
Transistor (IGBT) Converter
- Type of converter: transistor (IGBT)
- Max output power: 100 kW
- Output frequency 5 - 20 kHz
- Output voltage: 0 – 450 V
- Coefficient of efficiency: > 0,95
- Output power control range: 1 - 100 êW (0.0015 kW step)
- Output power stability: +/- 0,05%
Adaptive Automated Control System (ACS)
The adaptive (self-adjusting) ACS provides the control and stability through the whole growth process including the seeding. The significant advantage of the ACS is availability of several classes of automatic regulators, such as self-adjusting PID-regulator, incremental regulator, self-adjusting predictor-corrector which, as the practice has shown, provides for the best quality of a crystal shape control.