Investigation On Experimental Aluminum Microstructures Cutting

Aluminum and its alloys have the advantages of low density,high strength,and good thermal conductivity.Aluminum microstructures are widely used in the field of microelectromechanical systems(MEMS).However,due to the low hardness of aluminum,it will easily get deformed during machining.And it is difficult to achieve the processing size and accuracy of aluminum microstructure.Besides some non-contact machining methods such as micro-EDM and laser machining have the disadvantages of poor surface quality and low efficiency.This paper employs micro-scale linear tools to carry out experimental research on micro-electrochemical cutting,micro-electrochemical discharge cutting and tungsten wire cutting of aluminum micro-slit structure.The main research contents are as follows:(1)A micro-electrochemical cutting method based on sodium nitrate glycol solution was proposed to fabricate aluminum microstructures.First,the electrochemical dissolution phenomenon of aluminum in sodium nitrate solution and sodium nitrate glycol solution was analyzed.And it was found that sodium nitrate glycol solution could effectively reduce stray corrosion of aluminum during electrochemical machining.During the process,the effects of machining voltage,pulse frequency and duty cycle on machining quality of aluminum micro-slit structure were experimentally researched.Finally,the optimized processing paraments of voltage 10 V,pulse frequency 200 kHz,duty cycle 20%and feedrate 0.2μm/s were utilized to fabricate an aluminum micro-slit structure with average width of 283.1μm on 0.1mm thick aluminum foil.(2)A micro-electrochemical discharge cutting method based on sodium nitrate glycol solution was proposed to fabricate aluminum microstructures.This method could obviously improve efficiency without reducing processing quality.In this paper,the principle and processes including gas forming process and material removal process were analyzed.Four paraments including working fluid concentration,tool rotating speed,pulse frequency and feedrate were experimentally researched to find their effects on processing state and quality.It was found that relatively fast tool rotating speed was the key factor to keep the stability of processing.Finally,a rotating electrode with 200μm width was employed to fabricate aluminum micro-slit and micro-complex structures on 1mm thick aluminum foil,combined with optimized paraments of electrolyte concentration 1mol/L,voltage 12 V,pulse frequency 200 kHz,duty cycle 20% and feedrate 1.4μm/s.And the average width of aluminum micro-slit structure was 175.9μm and its surface roughness was 0.192μm.(3)A micro-cutting method using tungsten wire was proposed to fabricate aluminum micro-slit structures by which smaller scale micro-slit structures could be fabricated.In order to improve its stability and efficiency,the method of sequential feeding under the first / second feedrate was proposed.First,a breach near the edge of aluminum foil was machined under the first feedrate.Then,the aluminum micro-slit structure was fabricated under the second feedrate whose speed could reach 500μm/s.During the process,the effects of different first / second feedrate were experimentally researched to find their effects on width consistency and surface roughness.It was found that similar first / second feedrate could reduce surface roughness.Finally,an aluminum micro-slit structure with a length of 5 mm with good width consistency and surface roughness was fabricated on 0.1 mm thick aluminum foil by using a tungsten wire with diameter of 50μm.