Study On Deep Hole Machining Technology For Large Hot Die Forging Bottom Base

KP125MN hot die forging press is a kind of high efficiency press developed by EUMUCO in Germany at end of 1960s, it features small noise and vibration, less energy consumption etc.. This thesis gives a systematic analysis on deep hole machining of large steel casting with non-rotary type in the light of the deep hole machining technology ofφ120^+0.3mm×2550mm of bottom base of press, aiming at characteristic of heavy machinery machining, combining with practical production, we developed a set of deep hole machining system specially for bottom base from the points of technology, tooling and machining facilities, and it also can be applied for machining of other similar parts.In the light of the manufacturing of bottom base of KP 125 MN press respectively for Automobile No.1Co. and Tractor No.1Co., on the basis of analyzing the construction character of bottom base and machining performance of medium carbon steel casting, we comprehensively analyzed the machining range, accuracy, efficiency of typical conventional deep hole machining system, combining with the feature of heavy machinery machining, we came up with proposal of BTA (boring and Trepanning Association) combining solid drilling and BTA counter-boring for deep hole machining.We carried out systematical and theoretical analysis on mechanic mould, cutting principle, tool feature and breaking mechanism of chip of BTA tool, discussed the key issue of the tool which is used in deep hole machining of large steel casting with non-rotary type, came up with designing principle of tool, forming a proper tool construction, and designed the backing system and cooling oil returning system for drilling pipe positioning, sealing and rigidity reinforcement of drill pipe as per equipment condition.Based on the testing of steel grade 25 machining, we carried out rather complete technology tests on cutting performance to single-lip drill, welded multi-lip interlocking tooth drill, mechanical clamped multi-lip interlocking tooth drill, analyzed and studied technology parameters of deep hole machining on steel casting with non-rotary type on boring machine, set up a rather complete machining mould, combining with practice of enterprise, carried out demonstration analyzing on the mould, to make the mould reach a fairly high theoretical level and practical value. It is proved with practice that the designing of this system is reasonable with rather strong practicality, it can completely meet deep hole machining requirement of large steel casting with non-rotary type with medium diameter in heavy machinery industry.The main defects existed during machining are diameter over tolerance, axes deviation, poor roughness and spiral groove. Aiming to above-mentioned defects, we carried out theoretical analysis, came up with corresponding precautions which have a great value for reference to instruct production, an obvious effect has been obtained in practice.The system has successfully applied in production in enterprise, it is demonstrated with practice that the designing is correct, the construction is reasonable, with high efficiency and good stability, which has solved the problems in production.