A voxel-based kinematic simulation model for force analyses of complex milling operations such as wobble milling

Abstract

Mechanical machining of fiber reinforced plastics poses special challenges due to the heterogeneous and anisotropic material composition. Process strategies for the generation of drill holes, which aim at directing the resultant process forces toward the center of the workpiece, have been shown to obtain good machining results with less process induced damage. However, these strategies (e.g. wobble milling) might involve complex multiaxial tool movements and are thus very difficult to analyze and optimize. A voxel-based kinematic simulation program has been set up, which allows analyses of process forces for arbitrary milling operations based on the time-resolved determination of the cutting thickness and multivariate process force regression models. A basic analysis of the process of wobble milling is presented as well. It confirms that the resultant process forces are directed toward the center of the workpiece when the outer material layers are machined. The resultant force is directed in a favorable direction throughout the complete cut during the actual process step of wobble milling.

A review on strengthening, delamination formation and suppression techniques during drilling of CFRP composites

“…They stated that only tool inclination angle had a significant influence on effective force angle as compared to feed rate and cutting-edge radius. In the other study of Schulze et al (Schulze et al, , 2012, machining-induced damage was reduced by adopting complex machining strategies (five-axial advanced machining) in comparison to conventional drilling. In the recent article of Csongor Pereszlai & Norbert Geier (Pereszlai & Geier, 2020), comparing the wobble milling, helical milling with conventional drilling on CFRP, authors stated that wobble milling technique was more effective in minimizing the amount of uncut fibers.…”

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

“…Schulze and Beke [52] investigated the impacts of process and workpiece parameterssuch as feed, tool inclination, tool spiral angle and cutting-edge radiuson resultant machining force vectors. They also showed that wobble milling is insensitive to tool wear and they developed a mechanistic model to calculate chip geometry and specific forces in the scope of their study [51]. In addition, they figured out that during wobble milling the top laminated layers of CFRPs can be machined with the resulting process force vector directed towards the centre of the workpiece.…”

“…12 Impact of drilling strategies and cutting tools on the circularity errors of machined holes laminated layers of the composite. The burr area was expected to be larger in drilling operations than in the case of wobble or helical milling operations [50][51][52], because the axial cutting force (which bends the fibres at the exit of the hole) is higher during drilling.…”

“…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.…”

Influence of fibre orientation on cutting force in up and down milling of UD-CFRP composites

“…These may include (i) removing material build-up in the dividing plane of the laminating tool, (ii) removing excess material from the flange of the laminating tools, (iii) smoothing the mating surfaces of the laminated composites, and (iv) making holes for assembly of components [7][8][9]. Typically, these post-manufacturing needs are met by various machining techniques, like conventional drilling, helical milling, tilted helical milling, wobble milling, side milling, or edge trimming [6,[10][11][12][13].…”