A Study on the Effect of Different Lubrication Methods on Surface Integrity and Tool Wear during Ultrasonic-Assisted Milling of CFRP

Amirnia, Mahan | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54161 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Akbari, Javad
  7. Abstract:
  8. The aim of this study was to compare the effect of different cooling conditions (dry, flood, mql) on machined surface parameters (smoothness and protrusion of fibers) and tool erosion in carbon fiber reinforced plastic composite materials (CFRP) in the presence of ultrasonic vibrations or without it. Is. Today, carbon fiber reinforced plastic composite materials or CFRP have become one of the most widely used materials in industry due to their strength and light properties. For example, these materials have been used in the manufacture of products from commercial aircraft to shoes, tennis rackets, golf clubs, fishing rods, etc. The combination of carbon fibers woven with resin in alternating layers can lead to a high-strength, low-weight component compared to steel. Because carbon fiber is not damaged by bending and elongation and is very resistant, these composites are a good alternative to aluminum and titanium alloys and are used in the aerospace industry due to their light weight. Although CFRP components are made by molding, machining processes are often required to achieve final tolerances. CFRP machining processes, like all material machining processes, may be performed without the use of machining fluid or in the presence of machining fluid that is submerged or minimally applied. After designing and manufacturing the ultrasonic head, including the horn and tool holder and workpiece, an attempt was made to suggest the most appropriate machining method according to the accuracy required for the output parameters of the machined surface and various cooling facilities. After testing, it was found that the use of MQL (minimum quantity lubrication) compared to the water device reduces the surface roughness by 23%. Also, the presence of ultrasonic vibrations compared to the state without ultrasonic vibrations has a 13% reduction in surface roughness. The amount of fiber extrusion in MQL cooling method was much lower than other cooling methods (the length of the longest protrusion in MQL method was 0.024 of the longest protrusion in dry method). One of the main reasons for the reduction of fiber elongation was the spraying of oil and air solution that hit the contact area of the tool and the workpiece with high pressure
  9. Keywords:
  10. Minimum Quantity Lubrication ; Shear Force ; Tool Orientation ; Carbon Fiber Reinforced Plastic (CFRP) ; Milling Machining ; Rotary Ultrasonic Machining

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