Measurement of Spindle Thermal Growth on a Machine Intended for Micro/Meso Scale Milling

J.B Saedon,Sein Leung Soo,David K Aspinwall

doi:10.4028/www.scientific.net/kem.447-448.55

J.B Saedon, Sein Leung Soo + Show 1 more

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https://doi.org/10.4028/www.scientific.net/kem.447-448.55

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Journal: Key Engineering Materials	Publication Date: Sep 1, 2010
Citations: 1	License type: CC BY 4.0

Affiliation: University of Birmingham

Abstract

Micro milling is gaining ground as the preferred process for the manufacture of micro/meso-scale components in conventional workpiece materials, in particular for miniature moulds and tooling inserts (~ 60HRC), for the plastics injection moulding industry. Following a brief literature review on microscale milling and associated machine tool/tooling developments, experimental results are presented in relation to spindle thermal growth for a compensated/cooled spindle operating at up to 60,000 rpm, designed to accommodate the machining of meso-scale/micro-scale components. The work involved investigation of spindle warm up and cool down rates for speeds ranging from 30,000 - 60,000 rpm and subsequently the evaluation of spindle growth using both non-contact and contact measuring systems. Growth levels of up to 16µm were detected despite active spindle cooling and the incorporation of a standard compensation algorithm within the control system. Modification to spindle acceleration and deceleration rates reduced error levels by up to 50%.

Highlights

Demand and production for micro or miniature parts is increasing significantly year on year with volume manufacture reliant on advances in replication techniques such as micro-injection moulding, hot embossing etc
Microscale milling involves the use of high speed machine spindles with rotational speeds up to ~160,000rpm but more realistically 50,000 – 60,000 rpm and tooling in the range 60μm to 1mm in diameter
Some commercial machines for cutting at the microscale level are comparable in size to general purpose high speed machining centres a number of table top systems are available in the marketplace [1]

Summary

Introduction

Demand and production for micro or miniature parts is increasing significantly year on year with volume manufacture reliant on advances in replication techniques such as micro-injection moulding, hot embossing etc. Microscale milling involves the use of high speed machine spindles with rotational speeds up to ~160,000rpm but more realistically 50,000 – 60,000 rpm and tooling in the range 60μm to 1mm in diameter.

Results

Conclusion