Study On CAM Technology Of Electrical Discharge Machining Complicated Shape

Turbine blisk and engine chassis play an irreplaceable role in the field of aerospace engine, and determine the performance, reliability and cost of the power system to a great extent. Made of difficult-to-machine materials such as titanium alloy and nickel base superalloy, these two kinds of parts also have complicated shapes and precise profile requirements. Therefore, traditional mechanical processing methods are hard to obtain satisfactory results. Due to the EDM has many characteristics, such as, processing materials is widely, does not exist macroscopic force during the processing and machine tool can realize very complicated feeding movements, EDM has become one of the effective ways to process shrouded turbine blisk, and it also has a good application prospect in processing the engine crankcase.Firstly, this dissertation researched on the key technology of EDMing shrouded turbine blisk. The design and manufacture of shaped electrode are directly related to the machining precision of shrouded turbine blisk and the life of electrode. This dissertation introduced the basic principles and steps of the design of shaped electrode. According to the structure of a shrouded turbine blisk, an electrode designing system for EDMing shrouded turbine blisk is designed to generate forming electrode model automatically on the Unigraphics platform. The system consists of five modules, named electrode initial design, electrode thinning, electrode dividing, electrode base design and electrode feeding path planning.This dissertation then researched on the EDM milling CAD/CAM technology. A CAM system for EDM milling is established by studying its characteristics. According to the electrode wear in the process of EDM milling, the technology of electrode compensation is researched, the model of electrode compensation is established on the basis of uniform wear method, and the software of electrode compensation is created in terms of the model.Finally, experiments of EDMing shrouded turbine blisk and EDM milling were conducted. The reliability and practicability of electrode designing system are proved by processing qualified samples of shrouded turbine blisk. EDM milling experiments also show the workpiece precision is obviously improved after the electrode wear compensation model proposed in the dissertation is used.