Kerf Characteristics And Process Optimization Strategy Of CFRP/Al Stacks By Abrasive Waterjet Cutting Process

Carbon fiber reinforced plastic(CFRP)has many advantages such as excellent mechanical properties,good wear resistance,and strong designability.When CFRP laminates are connected with mental materials to form stack configurations,they can adapt to more complex and changeable use scenarios.Therefore,CFRP and its stack configuration are widely used in aerospace and automotive industries.However,CFRP is a typical difficult-to-process material due to its heterogeneity and anisotropy.When forming a stack configuration with metal for integrated processing,different material and processing properties greatly increase the processing difficulty.As a cold cutting processing technology,abrasive waterjet processing has the advantages of no thermal damage,small cutting force,low residual stress,and high processing versatility.However,in the current engineering application,abrasive waterjet machining technology still has the problem of poor machining surface quality and low dimensional accuracy to be solved urgently,which limits the further popularization and application of this technology.In this paper,CFRP and CFRP/Al stacks were taken as the research object,and kerf characteristics,influence law of process parameters,formation mechanism of defects and process optimization strategy of secondary cutting of CFRP and CFRP/Al stacks following abrasive waterjet machining.The main research results are as follows:(1)On the basis of energy method,the physical energy model of abrasive waterjet was established from the perspective of energy conversion during the formation of abrasive waterjet,and the internal relationship between the system parameters and the jet energy was analyzed.The experiment of cutting thick CFRP laminates with abrasive waterjet was carried out,and the influence of process parameters and power-to-speed ratio on the kerf characteristics was studied.Results showed that the surface quality and kerf taper could be improved effectively with smaller traverse velocity,higher hydraulic pressure,lower target distance and larger power-to-speed ratio.(2)Based on the research of thick CFRP laminates cutting,the experiment of abrasive waterjet cutting CFRP/Al stacks in single pass was carried out.The kerf characteristics and formation mechanism of two materials in different lamination sequences were studied.Results showed that lamination sequence had a significant influence on the profile of kerf,and the profile of kerf with different lamination sequences had completely different "V" and "X" shapes.Severe trailing stripes appeared on the surface of the material at the bottom of stack,which was closely related to the decrease of jet penetration ability.(3)The secondary cutting experiment of CFRP/Al stacks with abrasive waterjet was carried out to study the improvement effect of secondary cutting on kerf defects.Results showed that secondary cutting could effectively reduce kerf taper and improve the under-processing defects such as trailing stripes.However,the improvement effect of the secondary cutting was limited for over-processing defects such as large-area pits.In summary,this paper analyzes the process of energy conversion during abrasive waterjet forming,establishes the physical energy model of abrasive waterjet.The influence of process parameters on kerf characteristics and defect formation mechanism when abrasive waterjet cutting CFRP and CFRP/Al stacks are studied.The improvement effect of secondary cutting optimization strategy on the kerf defect is also studied.All these studies have lay a theoretical foundation for abrasive waterjet machining stack configuration materials.