Research On Rough Grinding Of Steel Castings Based On Industrial Robots

For large or medium-sized steel castings in the manufacturing industry,the working surface generally needs to be further machined to achieve the required working accuracy.But these surfaces often have problems such as casting riser or high hardness sand inclusion.If they are machined directly,not only the machining efficiency is low,but the key is that it is easy to cause damage to the machine tool and cutting tool.Therefore,it is necessary to remove the riser residue or sand inclusion buried in the material in advance by coarse grinding before machining.At present,the prominent problems of manual grinding are that it is difficult to ensure personal safety,it will cause personal pollution and excessive physical labor.Therefore,it is meaningful and feasible to choose industrial robot to replace human to finish coarse grinding of steel castings.According to the requirement of a cast steel enterprise in Qingdao,this research is completed in the test environment of its actual production site.The main research contents and conclusions are as follows.Firstly,based on the investigation of coarse grinding technology and casting grinding robots at home and abroad,the key points of the problem are determined: how to match grinding speed,feed speed and grinding depth of grinding wheel,and how to optimize grinding efficiency? At the same time,the force of grinding tools should be as stable as possible,so that the grinding system can obtain good working condition and service life.According to the requirements of manufacturers,such as durability,low failure rate,simple maintenance and low cost,the grinding tool is not designed with high cost and high maintenance six axis force sensor,but through a novel structure,using servo motor as the wheel drive source,through which the grinding tool is connected Through collecting the armature current to calculate the size and change of grinding force,so the design of grinding tool with powerless sensor is an innovation of this paper.Secondly,according to production experience and grinding force theory,the influencing factors of grinding force are determined,and the influence degree of each factor on grinding force is determined by single factor experiment.Taking the grinding efficiency as the optimization objective and the determined factor level as the element,the influence parameters of grinding efficiency were determined by orthogonal test.Then,according to the orthogonal test data,the grinding force values of grinding wheel under different grinding conditions are calculated.Through multiple linear regression analysis,the empirical formula of static grinding force is fitted.Then,the measured impact force waveform of coarse surface on the grinding wheel is analyzed by Fourier transform,and the dynamic impact response spectrum of coarse surface on the tool is fitted.The above multiple linear regression analysis and Fourier transform calculation,this paper uses the corresponding calculation tools in MATLAB,the analysis and calculation process is reliable.Thirdly,through the static / dynamic finite element analysis of grinding tool,the rigidity and dynamic stability of grinding tool and the selection of buffer structure material are verified.In practical work,the buffer structure requires a large static stiffness to prevent large static deformation,and it also requires a good shock absorption of the structure to protect the robot from large impact.In order to solve this contradiction,the buffer spring should be considered comprehensively from the material and structure.With the help of finite element simulation analysis,this paper gives a satisfactory solution.Finally,the research is summarized,and combined with the experience accumulated in the process of project implementation,the improvement scheme and Prospect of robot steel casting grinding are put forward.