Design of a five-axis ultra-precision micro-milling machine—UltraMill. Part 2: integrated dynamic modelling, design optimisation and analysis

Abstract

Abstract:Using computer models to predict the dynamic performance of ultraprecision machine tools can help manufacturers substantially reduce the lead time and cost of developing new machines. However the use of electronic drives on such machines is becoming widespread, the machine dynamic performance depends not only upon the mechanical structure and components but also the control system and electronic drives. Bench-top ultraprecision machine tools are highly desirable for micro manufacturing high-accuracy micro mechanical components. However the development is still at the nascent stage and hence lacks standardised guidelines. Part 2 of this two-series paper proposes an integrated approach which permits analysis and optimization of the entire machine dynamic performance at the early design stage.Based on the proposed approach the modelling and simulation process on a novel 5-axis bench-top ultraprecision micro milling machine tool -UltraMill is presented. The modelling and simulation cover the dynamics of the machine structure, moving components, control system and the machining process, and are used to predict the entire machine performance of two typical configurations.

Dynamic Characteristics Analysis of a Micro Grinding Machine Tool

“…However, this principle cannot be used in the design of miniaturized ultra-precision micro grinding machine tool, because the maximum spindle speed of the micro grinding machine tool can be up to 2000 Hz (120,000 rpm). Modal analysis results provide a frequency selection guide for machine operation rather than a threshold for maximum spindle speed [8].…”

Micro Milling

“…To meet the requirements for high dimensional accuracy, good form and surface finish for micro component manufacturing, micro milling machines are required to have high static loop stiffness, good thermal stability, low motion errors and high damping or dynamic stiffness [12]. Apart from commercial machines, a five-axis ultra-precision micro milling machine, as illustrated in Figure 8.4, has been built jointly by UPM Ltd and Brunel University [12,19], featuring a small footprint with good energy and resource efficiency, low production cost and high machining accuracy. Because of small diameter micro cutting tools, micro milling machines are commonly equipped with high speed and low run-out spindles.…”

Overview of Micro-Manufacturing

“…A bench-top, multiple-axis machine tool capable of machining intricate 3D geometries in components with nano-scale tolerances was developed [48][49], led by Brunel University and Ultra-Precision Motion Ltd of the UK. The associated new series developments include an air bearing slideway and a rotary table with improved damping capacity (patented) and an ultra-high-speed air bearing spindle (Loadpoint Ltd/Ultra-Precision Motion Ltd of the UK), a piezo-driven fast tool servo system and piezoelectric actuation unit for vibration assisted machining (CEDRAT Technologies SA of France), new micro-diamond tools (Contour Fine Tooling Ltd of the UK), a robotic arm unit for micro-components/tools handling and management (Carinthian Tech Research AG of Austria), and a tool and spindle condition monitoring system (University of Patras of Greece).…”