Improved stability predictions in milling through more realistic load conditions

M. Postel, N.B. Bugdayci, J. Monnin, F. Kuster, K. Wegener
2018 Procedia CIRP  
Permanent Link: https://doi.org/10.3929/ethz-b-000306899 Originally published in: Procedia CIRP 77, http://doi.org/https://doi. Abstract In today's business environment, the trend towards more product variety and customization is unbroken. Due to this development, the need of agile and reconfigurable production systems emerged to cope with various products and product families. To design and optimize production systems as well as to choose the optimal product matches, product analysis methods
more » ... e needed. Indeed, most of the known methods aim to analyze a product or one product family on the physical level. Different product families, however, may differ largely in terms of the number and nature of components. This fact impedes an efficient comparison and choice of appropriate product family combinations for the production system. A new methodology is proposed to analyze existing products in view of their functional and physical architecture. The aim is to cluster these products in new assembly oriented product families for the optimization of existing assembly lines and the creation of future reconfigurable assembly systems. Based on Datum Flow Chain, the physical structure of the products is analyzed. Functional subassemblies are identified, and a functional analysis is performed. Moreover, a hybrid functional and physical architecture graph (HyFPAG) is the output which depicts the similarity between product families by providing design support to both, production system planners and product designers. An illustrative example of a nail-clipper is used to explain the proposed methodology. An industrial case study on two product families of steering columns of thyssenkrupp Presta France is then carried out to give a first industrial evaluation of the proposed approach. Abstract In this paper, the combined influence of the load condition and the spindle speed on the tooltip dynamics of a five-axis milling machine with dominant spindle modes is evaluated. A constant preload is applied through axially and radially arranged permanent magnets while the dynamic excitation of the rotating dummy tool takes place by a force impact. The structures response is measured with non-contact sensors and Frequency Response Functions (FRFs) are calculated. The required load levels are derived from time domain simulation of the process. The soobtained stability charts are hence functions of the rotational speed and the load condition which in turn depends on the feed rate and depth of cut. For validation, cutting tests are performed in Aluminum 7075 and results are compared against the predicted lobes. The stability boundary resulting from this approach is capable to explain the shift of the stability pocket which is observed in the cutting experiments when comparing different feed rates. Abstract In this paper, the combined influence of the load condition and the spindle speed on the tooltip dynamics of a five-axis milling machine with dominant spindle modes is evaluated. A constant preload is applied through axially and radially arranged permanent magnets while the dynamic excitation of the rotating dummy tool takes place by a force impact. The structures response is measured with non-contact sensors and Frequency Response Functions (FRFs) are calculated. The required load levels are derived from time domain simulation of the process. The soobtained stability charts are hence functions of the rotational speed and the load condition which in turn depends on the feed rate and depth of cut. For validation, cutting tests are performed in Aluminum 7075 and results are compared against the predicted lobes. The stability boundary resulting from this approach is capable to explain the shift of the stability pocket which is observed in the cutting experiments when comparing different feed rates.
doi:10.1016/j.procir.2018.08.231 fatcat:iwjwkcrinzcnvmlznq6wdgv2tq