PVC-U molding profile extruder control system based on lonworks
By studying the dual-screw profile extruder used in PVC-U molding processing, presents a temperature computer control system in which a combined-control strategy of on-off control, fuzzy-control and integral-control were adaptive elected. The control system used Lonworks constructing a net to regulate the extruder's sub-areas temperature in line. App effect shows that the temperature control precision and the method of multi-subarea control in line with Lonworks filedbus has better effect than those sub-areas self-governed control, and can prevent PVC-U decompounding in the processing effectively, so the character of PVC-U manufacture could be improved.
Application of PLC to Temperature Control System in Extruder
The selection of both plastics material and plastics extrusion machine are very important during plastics extruding.The stability and accuracy of temperature control is extremely important in order to satisfactorily extrude plastics products.A method of temperature control system adopting PID algorithm,PWM(pulse width modulation) theorem based on PLC is dealt with,which is used in plastics extrusion machine.The hardware configuration and technology of software design are also given.The advantage of this method is its accuracy and reliability of temperature controlling.The result shows the overshoot is less than 3℃ and the precision reaches ±1℃ at stable state .
Phase formation during mechanical alloying in the Ti–Si system
Abstract Mechanical alloying of Ti–Si powder mixture or TiH 1.924 –Si powder mixture was performed by high-energy ball milling, in which the Ti to Si mole ratio was 1:2. The phase formations in both mixtures during milling were investigated by X-ray diffraction. Mechanical alloying a mixture of elemental powders led to the formation of TiSi 2 equilibrium compound, while when starting from Si + TiH 1.924 , a metastable phase was formed. The metastable phase completely transforms to TiSi 2 when the mechanically alloyed powder is annealed at temperatures above 800 °C. Two different pathways of phase transitions during mechanical alloying are attributed to the existence of hydrogen atoms, i.e., when starting from Si + TiH 1.924 compared to Si + Ti, the kinetics for the formation of the TiSi 2 intermetallic compound slows down. The kinetics related to the different phase transitions depending on the starting powder mixture are discussed.