Design-for-testing for improved remanufacturability

Katherine M M Tant,Anthony J Mulholland,Andrew Curtis,Winifred L Ijomah

doi:10.1007/s13243-018-0057-7

Katherine M M Tant, Anthony J Mulholland + Show 2 more

Open Access

https://doi.org/10.1007/s13243-018-0057-7

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Abstract

By definition, a remanufactured product must perform to the same (or higher) level as the original product, and must therefore be issued a warranty of the same (or longer) duration. However, many components of remanufactured products will have been subjected to regular stresses in their first cycle of use and may exhibit unseen signs of damage at a microstructural level. This may not affect the remanufactured product’s performance initially but could cause it to fail before its renewed warranty expires. To combat this, we propose that the integrity of individual components is assessed non-destructively before they are consigned to storage. However, lack of remanufacture specific tools and techniques for assessment, particularly non-destructive tools, are major hindrances to this strategy. Furthermore, ease of non-destructive testing (NDT) is not currently a consideration in the design of components; components with complex geometries may therefore be difficult to test. This preview paper presents, for the first time, a framework for including NDT suitability as a design criterion at the outset of the component’s lifecycle, where the geometry and surface accessibility of the component are optimised for future assessment. Ensuring that components can be easily inspected would not only allow increased confidence in the structural integrity of remanufactured products, but it would also extend the range of products suitable for remanufacturing. This paper serves as a proof of concept, examining simple inspection scenarios in order to demonstrate how the shape of components and data acquisition geometries can adversely affect the coverage of ultrasonic NDT.

Highlights

The majority of remanufacturing processes described in the literature follow a similar procedure: the cores are stripped; components are cleaned, visually assessed, remanufactured and Extended author information available on the last page of the articleJournal of Remanufacturing (2019) 9:61–72 stored; the product is rebuilt and its performance tested [13, 16, 21]
We propose that non-destructive testing (NDT) suitability is introduced as a secondary objective where the subset of solutions shown to be optimal for the existing objectives within a design process are subjected to an optimisation scheme which focusses on maximising the coverage of the ultrasonic field throughout the component whilst minimising the number of ultrasonic transducers required to achieve this
We examine the simplest case and compare the ultrasonic coverage of a steel disc placed in water against that of a rectangular steel block placed in water

Summary

Introduction

The majority of remanufacturing processes described in the literature follow a similar procedure: the cores are stripped; components are cleaned, visually assessed, remanufactured and Extended author information available on the last page of the articleJournal of Remanufacturing (2019) 9:61–72 stored; the product is rebuilt and its performance tested [13, 16, 21]. Due to a shortage of remanufacture-specific tools and expertise for the non-destructive inspection of these components [11], their integrity is often assessed by their exterior appearance and functional performance. It might meet initial performance criteria, interior damage of the structure caused by the strains and stresses experienced in the component’s earlier life-cycles could lead to a shorter lifetime than predicted [14]. Non-destructive testing (NDT) is an umbrella term for a wide range of analysis techniques used to evaluate and characterise components non-invasively [19] They are employed to detect defects, take thickness measurements and characterise the internal material properties of components. There already exists a large and varied literature on the applications of ultrasonic NDT, and the imaging algorithms required to process the collected ultrasonic data are under constant development [8, 24]

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