STUDY & DESIGN OF A SPECIAL TEST BENCH FOR HYDROSTATIC SPINDLE HOUSINGS

This paper deals with the study, design, manufacturing & testing of a particular scientific instrument, functional to investigate hydrostatic bushing behaviour under various experimental conditions. The job was conducted in concurrence with one of the leading companies in rotary transfer machines business. These machines are characterized by being turnkey solutions for the machining of parts requiring multi-sided machining processes and precision turning operations, starting from blanks or bar stock, for medium or high volume batch sizes. Typical rotary transfer architecture relies on a rotary table turret, where pieces to be machined are placed, rotating from one “station” to another. Each station has a particular process. Transfer machines are designed for a wide range of applications while production rate is as maximum up to 12.000 pieces/hour, with complete retooling in less than 1h. It must be understood that in a typical application, each station can comprise 2-3 machining “units” with their own spindle and its translating housing. For standardization purposes, there are a limited number of possible basic designs in machining “units”, subsequently each of them is accessorized to be functional to its target operation. Among them, one of the most prestigious is the hydrostatic unit, in which spindle assembly is contained in a sliding tube supported by a set of hydrostatic bushings. In this paper we will detail the design of a “research & test” bench whose aim is to help in developing new hydrostatic bushing systems and check production units, for quality issues.