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.
A Fuzzy-PID Control System of PTFE Sintering Furnace Based on Lonworks
This note introduces an industrial control system which adopts fuzzy-PID and Lonworks. According to the character of a class of time-delay and great inertia first-order system, we chose a combined-control strategy that On-off control or Fuzzy-control or PID control strategy were selected automatically, so accurate control to the four PTFE (Polytetrafluoro-ethylene) molding furnace sintering process such as sintering temperature, sintering time, cooling speed etc were achieved. App effect shows, temperature control precision is 0.5%, initial tracking error, maximum exceed error and final error are 2.5, 2.0 and 2.0 Celsius respectively. It proves that the combined-control system is better than the singularity structural such as PID or Fuzzy in fleetness and robustness and steady-state precision.
Molding and Sintering Process of PTFE Bulk Sample
The tests of pressing and sintering of PTFE powder were performed,and the relationship of density,compression strength and compression modulus with molding pressing force was discussed.The compression strength was analyzed under different sintering processes,and suitable pressing force and sintering process were presented.The results showed the compression strength of PTFE decreased with the increase of the molding pressing force,and the compression modulus of PTFE increased with the increase of the molding pressing force.The molding pressing force of PTFE was 27.5 MPa,sintering temperature was 380℃ and insulated hold time was 4 h.