Research On The Key Technology Of CFRP Drilling With Suction Type Internal Chip Removal

Carbon fiber reinforced plastics(CFRP)has been widely used in the field of aerospace because of its excellent physical and mechanical properties.The proportion of CFRP used in the aircraft has become an important basis to judge whether the aircraft is advanced or not,and also a concrete embodiment of whether a country’s international competitiveness is strong.Generally,CFRP parts need to be machined before installation,the most important of which is hole making,accounting for more than half of the total processing.Due to the characteristics of low interlaminar strength,anisotropy,high hardness and brittleness,CFRP materials have the following problems in hole making: the tool is easy to wear,the hole making defects are easy to occur,and the powder c hips produced cannot be discharged in time and effectively,which may lead to low production efficiency,low part yield,and the chips not recovered in time and effectively will harm the health and impact of workers Service life of the tool or machine tool.Aiming at the above problems,this paper proposes a new drilling process system-suction type internal chip removal system,and completes the establishment of the solution model of negative pressure of chip removal(that is,the study of the solution co nditions of negative pressure of chip removal),the establishment of prediction model of drilling force,the construction of internal chip removal system,the design of cutting tools for the system and other theoretical and experimental research.The details are as follows:In view of the problems mentioned above,this paper first presents a real-time and effective chip removal system in suction,which can discharge chips in real time during hole making,and introduces the composition and working principle of the system;secondly,aiming at the real-time and effective chip removal of the system,on the basis of chip classification,this paper presents the formation mechanism of different types of cutting and the chip negative pressure calculation of the system Based on the above cutting analysis theory,on the basis of the chip motion state in the equivalent analysis system,and on the basis of the particle suspension velocity solution theory in gas-solid two-phase hydrodynamics,the negative pressure solutio n model for the system to discharge chips of different equivalent diameters in time and effectively is established.Based on the data set obtained from the experiment and the theory of support vector regression machine,a prediction model of the relationship between tool parameters,cutting parameters and suction parameters and drilling force is established.The algorithm is designed to solve the unknown parameters in the model.Finally,the model is used to predict the influence of the above parameters on the axial force,which can provide theoretical support for the subsequent design of the bit structure(such as the length of the cross edge and the back angle)for the internal chip removal system and the selection of the processing parameters(such as the cutting parameters and the suction parameters)for the system processing.According to the requirements of drilling quality and chip removal effect of suction type internal chip removal system,based on the prediction model of drilling force and the solution model of system negative pressure,the design of internal chip removal drill head for the system is completed on the basis of analyzing the influence of tool parameters on the drilling force and chip removal effect.According to the requirements of the connection between the drill bit,the tool handle and the machine tool spindle,the internal chip removal requirements of the tool handle,the system chip suction power requirements and the chip collection and sealing requirements,the design of the syste m special external and internal chip removal tool handle and chip collection device with the internal chip removal flow channel is completed,and the manufacturing of the system components and the system construction are completed according to the above research content,which can be used for the subsequent internal chip removal The experimental study of chip hole making provides the basis.In view of the built suction type internal chip removal system,the comparative experiment with the external chip remo val device is carried out to verify that the real-time chip removal effect of the system meets the requirements and the correctness of the theory of solving the negative pressure of chip removal;based on the built suction type internal chip removal system,the comparative experimental research on the drilling quality of the bit is carried out.On the basis of verifying that the drilling quality of the internal chip removal bit meets the requirements,the next step is to carry out Step by step,the influenc e of suction parameters and cutting parameters on the drilling quality is studied;the comparative experimental study of bit wear is carried out,on the basis of verifying that the internal chip removal processing can effectively reduce the wear speed of each position of the bit and improve the service life of the bit,the further Study on the influence of suction parameters and cutting parameters on the wear speed and wear morphology of the bit is completed.The above research content can provide experimental reference for the optimization of suction internal chip removal system and the improvement of internal chip removal bit.