Optimizing Static and Dynamic Stiffness of Machine Tools Spindle Shaft, for Improving Machining Product Quality

Abstract

Automotive industries in Indonesia have grown up fast, and in-line with it, machine tools population has also grown up. Nevertheless, most of these machines are imported, because there are only few machine tools industries in Indonesia. Based on this situation, Indonesia has started to build its own machine tools industry in order to support mostly, automotive industries. This paper deals with an activity in machine tools performance improvement researches in Indonesia, that is, improving spindle static and dynamic stiffness. Spindle shaft is the weakest point in machine tools structure, increasing its stiffness will further increase machine tools accuracy and machining product quality as well. Moreover, high productivity needs machine tools with high speed machining capability, which leads into unavoidable dynamic effects that occur in the machine tool spindle during production process such as regenerative chatter. A study has been conducted on developing mathematical model for calculating static and dynamic stiffness of machine tools spindle shaft and studying changes of spindle shaft static and dynamic stiffnesses, by varying bearings preload, number of bearings, bearings span and spindle length. The study was conducted theoretically and experimentally on a national-built CNC vertical milling machine. The study shows that the machine tools spindle shaft stiffness can be increased by optimizing the parameters aforementioned.

Study on the Stiffness, Longevity and Reliability of the Spindle Unit of Eclipse 300 CNC Lathe with Different External Load

“…Mặt khác, Tri Prakosa et al [3] đã đi sâu nghiên cứu về cách đặt tải trước, khoảng cách ổ, số lượng ổ nhằm tăng độ cứng vững của cụm ổ trục chính. Holroyd et al [4] đã nghiên cứu và lựa chọn phương án tích hợp các cụm ổ lăn để xác định mối quan hệ giữa độ cứng vững và rung động của cụm trục chính.…”

Analyses of the effect of the design features of the spindle of the sliding table saw upon its critical rotational speeds

“…krzywych workowych determinujących obszary ich stabilnej pracy [1,3,8]. Inne podejście polega na zastosowaniu zmiennych prędkości obrotowych wrzeciona frezarskiego, gwarantujących jego odstrojenie od częstotliwości rezonansowej, przy której występują drgania typu chatter [4].…”

Structural Design Optimization of Movable-column Horizontal Machining Center Based on Integral Stiffness Analysis and Sensor Measurement

“…In short, previous studies adopted optimization schemes based on a structure analogy, the finite element method (FEM), and experience-based design, where only static stiffness was considered. (6)(7)(8)(9)(10) Regarding the high structural strength required for modern precision tool machinery, the existing machine-structure design methodologies are far from sufficient. Furthermore, many investigations on structure optimization problems for modules or whole machines have been reported.…”