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Stability and precision for crystal growing systems
PRF.¢Ib crucible containing the melt, which forms the crystal, and raises it so that as the level of melt drops as the crystal grows, the vessel is aligned correctly with the heat source. The Electro-Craft units used are the 650 motor and an open chassis version of the 652 amplifier, both from the company's "Motormatic' range. The 652 is a closed-loop completely transistorized velocity feedback amplifier which has an adjustable torque limit of 0-0.564 N m, dynamic braking and can be adapted to an external O-10 V source for remote speed control. Also, specifically for this application, the circuit boards are sealed to exclude moisture, as many of the crystal growing systems are exported to countries with humid climates. Electro-Craft Ltd, Third Avenue, Crewe, CWl lXU, U K
take account of graphite quality, ease with which the graphite powder produced by abrading may be flushed away, total surface area to be abraded and complexity of form. Maximum stroke of the tool carrier is 680 mm. Ingersoll Maschinen und Werkzeuge GmbH, 32 Charterland House, Queens Road, Coventry CV1 3EH, UK
Lathe incorporates ceramics The use of ceramics in all main components, including the spindle, bearings and headstock table, enables the SS-2 lathe to give a roundness deviation of less than 0.2 pm and a surface roughness of 0.1 pm. The machine, developed by Kyocera, is suitable for processing video equipment, office automation and optical components. The small thermal expansion of the fine ceramic allows accurate working without the need for heat control normally required for metal lathe turning machines. Due to its lightness; the ceramic has enabled the size and weight of the drive motor to be reduced. Maximum working diameter and length are 80 mm and 50 mm respectively. The operation range on the bed is 300 mm and that on the lateral feeding bed 200 mm. Rotation speed is 100-4000 rev rain -1. Kyocera Corporation, Corporate Communications, 52-11 Inoue-cho, Higashino, Yamashina-ku, Kyoto, Japan
Stability and precision for crystal growing systems High-precision motion control over long periods is an essential requirement for the high-pressure crystal growing equipment made by Cambridge Instruments to ensure that crystals have the correct electrical qualities and physical dimensions. The drive systems providing this accuracy and stability are multi-motor servo system packages from ElectroCraft. Each crystal puller has four motors and four amplifiers and they provide continuous life and rotational movement to an accuracy greater than + 1% over periods of up to 50 h. This long-term precision is largely the result of the motors' ability to develop
PRECISION ENGINEERING
Laser microscopes uses scanning technique
The servo motors from Electro-Craft help high-pressure crystal growing systems made by Cambridge Instruments to achieve precise motion control (+_ 1%) over periods of up to 5Oh. They are installed in pairs above and below the pressure chamber their 0.564 N m torque over their entire 5-5000 rev/min speed range and the amplifiers" ability to regulate motor speeds to an accuracy of better than 99% of the set speed and maintain full torque. The motors are mounted in pairs above and below the crystal growing chamber, and the amplifiers are incorporated in a control console. During the crystal growing process one of the top motors lifts the crystal at rates less than 10 mm/h whilst the other rotates it in the melt at speeds between 5 and 10 rev/min. Simultaneously the lower motors rotate the
Designed for applications in the study of semiconductor devices and the inspection of surface features, the new type of laser microscope developed by IBT Dubilier uses a scanning technique, The instrument, designated the SOM 100, has been designed to exploit the many advantages of scanning optical microscopy over conventional optical microscopy. In addition, unlike a scanning electron microscope, no vacuum is needed thus saving on maintenance and running costs. It can be used to visualize semiconductor defects and junctions by the technique of optical beam induced contrast (OBIC), and can also produce optical section images from which the height of surface features can be determined (confocal mode). In the OBIC technique, the incident laser beam induces a current in the device which is then used as the image contrast signal, The imaging resolution is sub-micron. OBIC has advantages over the equivalent EBICtechnique in the scanning electron microscope. The advantages of the OBIC technique are that examinations can be carried out without removing the passivation layer and that there is no electrical charge build up on the surface. The technique is thus suitable for the study of MOS devices such as power transistors, which are easily damaged by electrical charge build up. Other applications are in the
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take account of graphite quality, ease with which the graphite powder produced by abrading may be flushed away, total surface area to be abraded and complexity of form. Maximum stroke of the tool carrier is 680 mm. Ingersoll Maschinen und Werkzeuge GmbH, 32 Charterland House, Queens Road, Coventry CV1 3EH, UK
Lathe incorporates ceramics The use of ceramics in all main components, including the spindle, bearings and headstock table, enables the SS-2 lathe to give a roundness deviation of less than 0.2 pm and a surface roughness of 0.1 pm. The machine, developed by Kyocera, is suitable for processing video equipment, office automation and optical components. The small thermal expansion of the fine ceramic allows accurate working without the need for heat control normally required for metal lathe turning machines. Due to its lightness; the ceramic has enabled the size and weight of the drive motor to be reduced. Maximum working diameter and length are 80 mm and 50 mm respectively. The operation range on the bed is 300 mm and that on the lateral feeding bed 200 mm. Rotation speed is 100-4000 rev rain -1. Kyocera Corporation, Corporate Communications, 52-11 Inoue-cho, Higashino, Yamashina-ku, Kyoto, Japan
Stability and precision for crystal growing systems High-precision motion control over long periods is an essential requirement for the high-pressure crystal growing equipment made by Cambridge Instruments to ensure that crystals have the correct electrical qualities and physical dimensions. The drive systems providing this accuracy and stability are multi-motor servo system packages from ElectroCraft. Each crystal puller has four motors and four amplifiers and they provide continuous life and rotational movement to an accuracy greater than + 1% over periods of up to 50 h. This long-term precision is largely the result of the motors' ability to develop
PRECISION ENGINEERING
Laser microscopes uses scanning technique
The servo motors from Electro-Craft help high-pressure crystal growing systems made by Cambridge Instruments to achieve precise motion control (+_ 1%) over periods of up to 5Oh. They are installed in pairs above and below the pressure chamber their 0.564 N m torque over their entire 5-5000 rev/min speed range and the amplifiers" ability to regulate motor speeds to an accuracy of better than 99% of the set speed and maintain full torque. The motors are mounted in pairs above and below the crystal growing chamber, and the amplifiers are incorporated in a control console. During the crystal growing process one of the top motors lifts the crystal at rates less than 10 mm/h whilst the other rotates it in the melt at speeds between 5 and 10 rev/min. Simultaneously the lower motors rotate the
Designed for applications in the study of semiconductor devices and the inspection of surface features, the new type of laser microscope developed by IBT Dubilier uses a scanning technique, The instrument, designated the SOM 100, has been designed to exploit the many advantages of scanning optical microscopy over conventional optical microscopy. In addition, unlike a scanning electron microscope, no vacuum is needed thus saving on maintenance and running costs. It can be used to visualize semiconductor defects and junctions by the technique of optical beam induced contrast (OBIC), and can also produce optical section images from which the height of surface features can be determined (confocal mode). In the OBIC technique, the incident laser beam induces a current in the device which is then used as the image contrast signal, The imaging resolution is sub-micron. OBIC has advantages over the equivalent EBICtechnique in the scanning electron microscope. The advantages of the OBIC technique are that examinations can be carried out without removing the passivation layer and that there is no electrical charge build up on the surface. The technique is thus suitable for the study of MOS devices such as power transistors, which are easily damaged by electrical charge build up. Other applications are in the
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