Optimisation of process parameters for the orbital and conventional drilling of uni-directional carbon fibre-reinforced polymers (UD-CFRP)

Analysis of Characteristics of Surface Roughness of Machined CFRP Composites

“…Results of drilling experiments, concerning (i) average surface roughness, (ii) roughness depth and the (iii) factorial analysis (based on response surface methodology and analysis of variance) can be read in a previous paper of the authors [41]. The surface roughness parameters were measured by the Mitutoyo contact profilometer, each surface n = 5 times.…”

“…Due to the extremely high experimental costs, the number of experiments had to be minimized, the central composite inscribed DoE method was therefore used to design conventional drilling and helical milling experiments. Factors and their levels were chosen based on previous researches [11,[41][42][43][44][45][46] and suggestions of tool producers. The experimental design table can be seen in Table 2.…”

Comparative analysis of wobble milling, helical milling and conventional drilling of CFRPs

“…Nevertheless, after the curing processes, there are still many micro-and macro-geometrical features that have to be machined mechanically. In the aerospace industry, thousands of high-quality holes have to be machined in order to assemble CFRP parts [6,7]. However, CFRP composites are difficult-to-cut materials due to their (i) anisotropic and (ii) inhomogeneous features, and because of (iii) the abrasive wear effects of their carbon fibres on the cutting tool [8][9][10][11][12].…”

“…In case improper machining technology is applied when machining CFRPs, many micro-and macro-geometrical damages can be generated easily: such damages include delamination [6,7,[14][15][16][17][18][19][20][21][22][23][24], uncut fibres and pull-outs [13,[25][26][27][28][29][30][31] as well as microcracks on the machined surfaces [30,[32][33][34]. In order to minimize the above-listed damages, there are many process and technological parameters that have to be optimized including (i) the geometry and coating of the cutting tool [18,33]; (ii) the cutting speed, feed rate and the depth of cut [7,18,35]; (iii) the tool path [7,13,32]; (iv) the cooling [36][37][38][39]; and (v) the type of support plate [40][41][42].…”

“…Even if previously many researchers investigated the impacts of technological and process parameters on conventional drilling induced damages in CFRPs, the number of scientific studies as far as the helical [7,32,35,[43][44][45][46][47], tilted helical [48,49] and wobble milling [50][51][52] of CFRPs are concerned is limited.…”