Design And Research Of Loading And Unloading Robot For Hollow Wax Parts

With the development of science and technology,the level of industrial automation technology has been rapidly improved.Wax,as one of the important industrial production materials,has been widely used in lost wax casting.In order to improve the quality of wax pattern,a foundry used five-axis engraving machine to process wax pattern blanks directly instead of manual silica gel to make wax pattern,which improved the accuracy and yield of the product.Because the hollow wax parts are easy to be broken and deformed when they are transported and loaded at room temperature,most of them are manually loaded and unloaded.Aiming at the problems of low production efficiency and high cost of manual feeding and unloading,a kind of mechanical hand which can complete automatic feeding and unloading of hollow wax parts is proposed.Therefore,on the basis of comprehensive application of mechanical design and automatic control knowledge,the design of a manipulator to grasp hollow wax parts requires that the designed manipulator not only grasp stably,but also ensure that wax parts are not damaged.The research has important practical value for lost wax casting industry to improve production efficiency,reduce energy consumption and material consumption.In this paper,the work of loading and unloading hollow wax parts as the research object is mainly carried out in the following aspects:(1)The physical characteristics of hollow wax parts with different thickness and diameter were measured,which provided a theoretical basis for the design of the subsequent end-effector.In order to reduce the rigid contact damage during the clamping process,the friction coefficient between wax parts and four kinds of elastic materials was measured,and the suitable clamping contact material was selected.(2)Based on the physical characteristics of wax parts,a follow-up three-finger clamping mechanism with envelope grabbing and pressure feedback is designed.Its working principle and process are described,and the theoretical analysis and structural design of the main components are completed.Based on the production process requirements,gantry conveying mechanism was designed,and the moving speed of the manipulator was determined according to the production rhythm.(3)The kinematics equation of the clamping mechanism is established.Based on ADAMS simulation software,the dynamic simulation of the end effector is carried out with the representative vertebral body as the clamping object.The results show that the clamping mechanism can effectively grasp under the given clamping force.Using ANSYS Workbench finite element analysis software,the dynamic and static analysis is carried out.The strain diagram,equivalent stress diagram,modal mode shape and harmonic response curve of key components are obtained,and the feasibility of the design scheme of conveying mechanism and clamping mechanism is verified.(4)A combined control system based on PLC and microcontroller is designed,and a man-machine interface which is easy to learn and operate is developed to realize the control of conveying mechanism and clamping mechanism.Using RS485 communication technology,the connection between controllers is established,and the design and manufacture of manipulator control system are completed.(5)According to the above research methods,a prototype of loading and unloading manipulator is manufactured.After practical application,the requirements of automatic grasping,conveying and precise positioning of hollow wax parts are met,and the automatic loading and unloading of hollow wax parts is completed.