Forces In Helical Milling Research Articles

Modeling of cutting forces in helical milling of unidirectional CFRP considering carbon fiber fracture

Helical milling is applied to the machining of CFRP owing to its favorable characteristics such as low cutting forces and heat generation. However, the prediction of helical milling forces remains a problem in CFRP processing. In this study, a novel predictive cutting force model of helical milling for unidirectional CFRP was established. Based on the cutting parameters, the dynamic cutting angle for the fiber and the corresponding cutting states of the fiber during the cutting process were analyzed, and the number and length of cutting edges involved in cutting were calculated. Then, the cutting forces on the cutting-edge micro-element of the periphery edge and bottom cutting edge under two different cutting states were calculated by treating the fiber as an equivalent homogeneous material. The cutting force prediction model was obtained by taking this into consideration. Finally, the helical milling experiment for unidirectional CFRP was carried out. The results show that the model can effectively predict the cutting force. • A new prediction cutting force model of Helical milling for unidirectional CFRP was established. • The model is based on the fracture mode of carbon fiber and cutting edges micro-element cutting force.

Multivariate robust modeling and optimization of cutting forces of the helical milling process of the aluminum alloy Al 7075

Helical milling is an advanced hole-making process and different approaches considering controllable variables have been presented addressing modeling and optimization of machining forces in helical milling. None of them considers the importance of the noise variables and the fact that machining forces components are usually correlated. Exploring this issue, this paper presents a multivariate robust modeling and optimization of cutting forces of the helical milling of the aluminum alloy Al 7075. For the study, the tool overhang length was defined as noise variable since in cavities machining, there are specific workpiece geometries that constrain this variable; the controllable variables were axial feed per tooth, tangential feed per tooth, and cutting speed. The cutting forces in the workpiece coordinate system were measured and the components in the tool coordinate system, i.e., the axial and radial forces, were evaluated. Since these two outcomes are correlated, the weighted principal component analysis was performed together with the robust parameter design to allow the multivariate robust modeling of the mean and variance equations. The normal boundary intersection method was used to obtain a set of Pareto robust optimal solutions related to the mean and variance equations of the weighted principal component. The optimization of the weighted principal component through the normal boundary intersection method was performed and the results evaluated in the axial and radial cutting force components. Confirmation runs were carried out and it was possible to conclude that the models presented good fit with experimental data and that the Pareto optimal point chosen for performing the confirmation runs is robust to the tool overhang length variation. Finally, the cutting force models were also presented for mean and variance in the workpiece coordinate system in the time domain, presenting low error regarding the experimental test, endorsing the results.

A mechanistic model for cutting force in helical milling of carbon fiber-reinforced polymers

Recently, carbon fiber-reinforced polymers (CFRPs) are widely used in the transportation, aerospace, and chemical industries. In order to complete reliable connection with other materials, hole-making performance about CFRP must be systematically studied. While as the typical difficult-to-cut material, tool wear will be very serious in the CFRP cutting process, which will directly influence the change of cutting force, and the larger of the cutting force will lead to the occurrence and propagation of delamination of the holes. In this paper, to accurately predict cutting forces in helical milling of CFRP, a mechanistic cutting forces model considering the fiber cutting angle is established according to cutting principle of helical milling. Based on experimental data, cutting force coefficients are identified according to unidirectional CFRP using average-based method and fitted by response surface methodology (RSM). The results show that the new established force model with the cutting force coefficients can improve the accuracy of the cutting forces, thus achieving an accurate estimate of cutting forces in helical milling of carbon fiber-reinforced polymers.

Research on the Relation between Cutting Parameters and Axial Cutting Force in Helical Milling Process

The select of cutting parameters is not only directly related to the productivity, but also related to the change of cutting forces. Axial cutting force is too large to be ignored in the helical milling process. In this paper, the axial forces in helical milling of Cold die steel under different cutting parameters are measured, and the regression model of the axial force about the change of the cutting parameters is established, the influence of the cutting parameters on the axial cutting force is analyzed through the experimental results and the regression models respectively. The main purpose is to control axial cutting force and improve tool life in the cutting process.

Modeling of cutting forces in helical milling by analysis of tool contact angle and respective depths of cut

Knowledge of the behavior and magnitude of cutting forces is very important for correctly calculating cutting power and for obtaining tight tolerances and low levels of tool wear. In this way, the appropriate prediction of the force components collaborates with the correct choice of the cutting parameters and strategies. High oscillation of force values in helical milling increase the relevance of the analysis. In this context, present work describes an approach for modeling cutting forces in helical milling based on the analysis of tool contact angle and the respective depths of cut. From the model, it is possible to predict the behavior and magnitude of the force acting on the insert, which contributes to better process planning. The results indicated a good fit of the experimental values with the models, despite the observation of some errors, which occurred mainly due to the dynamics of the machine and the used approximations.

Analysis of cutting forces in helical milling of carbon fiber–reinforced plastics

The carbon fiber–reinforced plastics have gained considerable attention in the aerospace industry in recent years. Drilling of carbon fiber–reinforced plastic is relatively difficult with too much fiber delamination and pulling out in the entry and exit of the holes. As an advanced hole-making technology, helical milling is being developed in machining of carbon fiber–reinforced plastic, in which the tool moves on a helical course to the workpiece. Experiments were carried out on helical milling of carbon fiber–reinforced plastic, the effects of the cutting parameters and tool wear on the cutting forces are analyzed, and the relation between hole quality and cutting forces is also discussed. In order to simulate the cutting forces under different cutting conditions, the mechanistic modeling technique is used to predict cutting forces in helical milling of carbon fiber–reinforced plastic, and the cutting force coefficients are identified and corrected based on the experimental data. The results show that the established model can be used to predict the cutting forces in the helical milling process.