The Optimization Of Excavator Working Device Machining Process

The working device of hydraulic excavator includes a boom,an arm and a bucket. These three components connected with the coupling pin, pushed by cylinders, its can complete lifting, falling, digging, rolling and other actions. Working device structure is complex, contour size is large, its manufacturing precision and reliability make a great influence on the machine life and reliability. This project purpose is to study large-scale structure of the welding manufacturing technology in several key aspects of the company to find ways to improve the manufacturing level of structural parts. On the welding technology of the structural parts, explore the design technique and principle of the technology equipment. To the method of controlling the welding deformation, through the actual test we got the practical data and experience. Select the appropriate company realistic pretreatment methods to against the welding deformation of structural parts. On the machining technology of the structural parts, we find out the crux and attentions of machining the thin-box structural parts, put forward to improve the quality of technical methods. Explore the measure technology of the machining on line to improve the productiveness. During the analysis of how to improve the machining technology and the efficiency, how to reduce the manufacture cost, we summarized some effective methods to the trade of structural parts.Excavator working device manufacturing process include cutting, welding, machining and painting, all together have four major steps. Welding and machining process are the most important link which are easy produce the problems lead to poor quality. To these two steps, since the machining process on the back, so that various accumulated errors which are generated by welding are ultimately reflected in this processing. Actual production in the factory during the processing of the mainly reflected in:1Because of the structure of the part is thin-box, weld layout is complex, the distance of each seat which to install the coupling pin is far, welding deformation is large. To the rough parts, center distance between each seat and axis parallel to each other has a big deviation to the drawings before machining. 2If the boring in accordance with the name dimension of drawings, excessive welding deformation will make the actual dimension deviate seriously, and the cutting allowance is not symmetrical, the hole unable to be cutted overall, so the rough surface is remained. In order to avoid this situation arising, we need to adjust the actual cutting position of each hole through the test procedure before the formal machining. The target is the actual cutting position can ensure the actual dimension is permitted to the tolerances and on the same time rough surface is not remained. This target is achieved by a tool test program. Time-consuming and adjust difficulty.3Because the improper selection of the chip, there are other problems in the machining processing, for example:cutter edge is easy to be damaged,chip exhaust is difficult and cutting efficiency is low.According to above-mentioned questions, this project made the following experiments to get the improvements:improved the cutting precision of blanking parts, preset weld shrinkage and improve welding sequence to reduce welding deformation; by adding the measurement program, presetting the offset parameters to cancel t tool test program and improve the machining efficiency; through the cutting tests, find out a better material of the chip to reduce the edge damaged, poor chip exhaust and so on. In the middle of these improvement the measurement on-line during machining processing is the first time be used in the same industry trade.