Low Thermal Expansion Machine Frame Designs Using Lattice Structures

Poom Juasiripukdee,Ian Ashcroft,Ian Maskery,Richard Leach

doi:10.3390/app11199135

Poom Juasiripukdee, Ian Ashcroft + Show 2 more

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https://doi.org/10.3390/app11199135

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Journal: Applied sciences	Publication Date: Sep 30, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Nottingham

Abstract

In this work, we investigated tessellating cellular (or lattice) structures for use in a low thermal expansion machine frame. We proposed a concept for a lattice structure with tailorable effective coefficient of thermal expansion (CTE). The design is an assembly of two parts: a lattice outer part and a cylindrical inner part, which are made of homogenous materials with different positive CTEs. Several lattice design variations were investigated and their thermal and mechanical performance analysed using a finite element method. Our numerical models showed that a lattice design using Nylon 12 and ultra-high molecular weight polyethylene could yield an effective in-plane CTE of 1 × 10−9 K−1 (cf. 109 × 10−6 K−1 for solid Nylon 12). This paper showed that the combination of design optimisation and additive manufacturing can be used to achieve low CTE structures and, therefore, low thermal expansion machine frames of a few tens of centimetres in height.

Highlights

Temperature fluctuations, even in controlled laboratory environments, can cause alignment drift in high-precision measuring machines, as their support frames undergo thermal expansion and contraction [1]
The geometrical complexity enabled by additive manufacturing (AM) provides new opportunities [3,4,5,6,7] for low-coefficient of thermal expansion (CTE)
Akihiro et al [12] and Takezawa et al [13] applied the same approach to the internal geometry of porous composites, resulting in planar negative

Summary

Introduction

Temperature fluctuations, even in controlled laboratory environments, can cause alignment drift in high-precision measuring machines, as their support frames undergo thermal expansion and contraction [1]. This can lead to significant measurement uncertainty and, represent a significant issue in precision engineering [2]. The design of structures with low or tailorable CTE is a growing research topic, with applications identified in aerospace, optical measurement systems, and precision instruments [8,9,10]. Sigmund et al [11] proposed three-phase composites (Invar, nickel and voids) using topology optimisation to design structures with positive, zero, and negative CTE. Akihiro et al [12] and Takezawa et al [13] applied the same approach to the internal geometry of porous composites, resulting in planar negative

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