| With the vigorous development of the aerospace industry,carbon fiber reinforce plastic(CFRP)and their metal laminates have been widely used in aircraft to manufacture major load-bearing components.To ensure the quality and efficiency of hole,a series of advanced hole-making equipment and hole-making technology are required.Due to the huge size of many aerospace components,it is necessary to perform hole processing at the assembly site.At this time,for some small hole-making stations,large-scale automated hole-making equipment such as robotic arms cannot enter,and workers need to use hand-held pneumatic drill to drill holes.Pneumatic drills cannot intelligently adjust the drilling parameters.The axial force of the feed needs to be controlled by the experience of the worker.It is difficult to ensure the stability of the hole making quality.When the hole diameter is too large or drilling high-strength materials such as titanium alloys,the axial force is too large to allow workers to perform manual feed operations,so it is necessary to develop special hole-making equipment which suitable for small spaces,and at the same time explore suitable drilling process solutions and combine them with the equipment to provide a set of high-quality and efficient automated hole-making solutions in the narrow space.This paper focuses on the development of portable variable parameter automatic feed drilling equipment,and conducts research in the following aspects.(1)According to the important application conditions of the equipment and the large thickness CFRP drilling process,the drilling drilling section is divided,the mechanical and thermal characteristics of different drilling sections during the drilling process are studied,and the proper drilling parameters of each section are obtained.On this basis,a process method for drilling large thickness CFRP plates with variable parameters in sections is proposed.(2)Combining the large-thickness CFRP hole-making process,laminated hole-making process,and the requirements of operating conditions in a narrow space,a small-scale automatic feed drilling equipment structure design scheme is proposed,On this basis,the structural design of the whole machine parts is selected.At the same time,the strength of key components is checked and complete the assembly of the virtual prototype.The equipment independently drives the rotation and feed motion through dual servo motors,and the spinning speed and feed speed is infinitely adjustable.An auxiliary axial low-frequency vibration auxiliary drilling module was added when drilling metal materials to achieve chip breaking function.The whole machine is compact in structure and light in weight.With the special drill template,it can be quickly disassembled and assembled,and high-quality integrated hole making of CFRP and its laminated materials is completed.(3)Combined with the drilling mechanism,the PLC controller is used as the carrier to compile the automatic control program of the equipment to achieve high-precision control of the servo motor,add a force acquisition module to monitor the drilling axial force data in real time,judge the drilling materials and working conditions,and form a feedback control for the speed,complete automatic variable-parameter hole making of single and stack material,set multiple safety protection functions to ensure the stable operation of the equipment in the complex working environment.(4)Completed equipment assembly and commissioning,Cooperate with variable parameter process,conducted a series of hole making experiments for CFRP and titanium alloy Test the drilling performance of the equipment and check the various indicators of the hole,the hole making quality is wel,which can meet the needs of aviation hole making. |
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