Heat partition in edge trimming of fiber reinforced polymer composites

Abstract

Thermal loading of fiber reinforced composites during traditional machining is inevitable. This is due to the fact that most of the mechanical energy utilized in material removal is converted into heat, which is subsequently dissipated into the workpiece and the cutter, and is carried away by the chips. Heat conduction into the workpiece during machining might cause thermal damage due to matrix softening and decomposition if the generated temperatures exceeded the glass transition temperature of the epoxy resin. In this work, the amount of heat flux applied to the machined edge and the temperature distribution in multidirectional CFRP and GFRP composite laminates was determined using an iterative inverse heat conduction method. The transient heat conduction problems in the laminate and cutter were simulated independently using the finite element method and the amount of heat flux applied to each was determined. It was also found that the heat flux conducted to the workpiece represented only a small fraction of the total heat and is more influenced by the feed speed than the spindle speed. The temperature of the machined surface was estimated and correlations with the resulting machined surface texture were made.

Thermal Aspects in Edge Trimming of Bio-Filled GFRP: Influence of Fiber Orientation and Silica Sand Filler in Heat Generation

“…Many researchers have discussed the challenges encountered in machining composite materials by addressing four topics: (1) optimization of the cutting parameters [ 13 , 14 , 15 , 16 , 17 , 18 ], (2) machined surface quality [ 18 , 19 , 20 , 21 ], (3) cutting tool life [ 22 , 23 , 24 , 25 ], (4) heat partition, and (5) thermal effects [ 25 , 26 , 27 ]. Indeed, each of these topics treats a side of the possible damage occurring in composite material work-pieces as well as cutting tools during machining.…”

“…They deduced, through the analysis of variance of previously conducted polymer composite machining tests, that the use of low feed rate with moderate cutting speed allows for the slowing down of tool wear accelreation. According to Sheikh-Ahmad et al [ 25 ], the hardness of the cutting tool drops when its temperature rises during processing, which causes the acceleration of its wear. Actually, dry machining of FRP materials is more preferred than wet processing conditions [ 28 ].…”

“…As a result, the increase in cutting temperature is axiomatic and it presents another challenge for researchers and industrialists, since it causes aggressive tool wear and evenly matrix thermal damage. Recent studies [ 25 , 26 , 27 ] were motivated to introduce the heat partition into the work piece by using different techniques and methods to measure cutting temperature and to estimate their influences on the quality of the machined parts. Liu et al [ 27 ] used the Conjugate Gradient Method, and they pointed out that 21% of the generated heat is evacuated through the composite specimens during milling.…”

“…Liu et al [ 27 ] used the Conjugate Gradient Method, and they pointed out that 21% of the generated heat is evacuated through the composite specimens during milling. Using the inverse heat conduction technique, Sheikh-Ahmad et al [ 25 ] found that the heat partition ratios in the composite sample, chips, and tool were 0.07, 0.37, and 0.56, respectively. In another work [ 29 ], the authors deduced that the heat flux conducted through a GFRP edge trimmed surface was more influenced by the feed rate rather than the spindle speed.…”

Heat Analysis of Thermal Conductive Polymer Composites: Reference Temperature History in Pure Polymer Matrices

“…From experiments, it was observed that a more robust geometry, with a lower rake angle and a higher cutting-edge radius, favors the thrust force rise, hence resulting in delamination and burrs. Sheikh-Ahmad et al [ 24 ] pointed out that the rise of the cutting tool temperature causes drops in its hardness and consequently accelerates tool wear. Indeed, besides the tool life and the final composite structure quality, increase in cutting temperatures during the machining process can significantly affect the cutting mechanisms themselves, and therefore, the adjustment range of cutting parameters.…”