Reserch On Facility Of Control & Inspection In Plasma Powder Deposition Manufacture

PPDM(Power Plasma Deposition Manufacturing)is a method of direct rapid metal manufacturing and tooling,it can sharply shorten the lead-time,reduce the cost of product and shape up full-density metal die, therefore it has great future in the RM & Aero-Part industry. Because a lot of factors disturb the processing of PPDM, these is a long way to go to improve the precision of production. Our research team dedicated to developing an Open-CNC system and doing a closed-loop control with deposition for PPDM. It needs sampling the various parameters and keeping real-time control in deposition processing. This article focus on the research of the deposition control System design in the plasma deposition rapid prototyping equipment. Used embedded microprocessor ARM and external signal conditioning circuit as the hardware of the deposition control, and used the embedded software platform as the development of under-control software, which have a high performance in data processing and the implementation of logic function.The deposition control system used LPC2136 of the excellent 32 bit ARM7 processor as the core of control and realized the melting plot manual control and automatic timing control; through the design of the external signal conditioning circuit, transforming the external parameters of the analog signal into a digital signal and send the data to the PC; interconnection with the mainframe through RS-232 serial interface realized data communication; interaction with the signal of the motion control card PMAC, achieving machine campaign and deposition control synchronization function. The article studied the sequential process of PPDM deeply, and accurate sampling of external parameters, protocol definition of the melting plot synchronization etc.The software system consists of two modules: the management module between the control of tasks under the real-time embedded operating system platform and chip peripherals drivers control module. The task management module was used for the creation and priority settings of task, scheduling between tasks. The peripherals drive control module of chip was used for controlling many function modules of units, such as A/D sampling module, I2C driver module, UART communication module, input/output module, and the initialization and activation of those control registers.The system is complete of control function both hardware and software, it will not only achieve independent control process of PPDM and sampling parameters, but also can establish the link between PMAC card. It is an important part to constitute closed-loop control with PPDM. Moreover, its high openness provides a broad platform to make functions expansion.