# A Social Life Cycle Assessment Framework for Additive Manufacturing Products
## 1 Introduction  
Additive Manufacturing (AM) technology, usually referred to as 3D printing, is gaining importance in various fields of business and industries due to its significant potentials [1]. Despite being an immature technology, AM has proved to have a considerable potential for sustainable manufacturing [2]. According to [3], \"AM is expected to become a key manufacturing technology in the sustainable society of the future\". However, very few studies have been conducted regarding the understanding and assessment of AM social impacts [4]. This lack of knowledge leaves a research gap in the body of literature. This research aims to fulfill this gap by adopting a framework to assess the social impacts of an AM product throughout its different life cycle stages. In [5], the social impacts of a product are defined as the consequences of social interactions formed between the product's surrounding system and the stakeholders engaged in the product life cycle.  
Even though there are several tools and methods in the literature to assess the social impacts of products, the most common methodology among the international community, and also the most used methodology in case studies developed in this knowledge area is the Social Life Cycle Assessment (SLCA) [6]. SLCA is considered as a Life Cycle Assessment (LCA) methodology that complements the Environmental Life Cycle Assessment (E-LCA) and Life Cycle Costing (LCC), with the social and socio-economic aspects contributing to the full assessment of goods and services within the context of sustainable development [5]. SLCA can either be applied on its own or in combination with E-LCAand LCC. SLCA methodology assesses the social impacts of a product from a life cycle perspective by looking at the complete life cycle of a product, from extraction to disposal [5]. SLCA is the only social assessment methodology that considers the social impacts of products from a life cycle perspective [7].  
There are various references and methodological frameworks when conducting a SLCA study. The authors in [8] have identified 14 SLCA methodological frameworks in their review. However, the general methodology for SLCA implementation mostly relies on the \"UNEP/SETAC Guidelines for Social Life Cycle Assessment of Products\" [5] from which more specific measurement frameworks or tools can be derived and, therefore, it is selected as the reference for this research. It provides guidance for the assessment of the social and socio-economic impacts of the products along their life cycle.  
The research carried out for this paper revealed that several studies of SLCA were conducted to evaluate the social impacts of products manufactured by conventional manufacturing. However, no study was found that applied the SLCA methodology towards the social impacts of AM products. Therefore, the main objective of this study is to develop a SLCA framework to assess the social impacts of AM products on different stakeholders within different product life cycle stages. To this end, the present study focuses on the following objectives:  
* Identification of possible indicators and metrics for measuring AM social impacts.
* Development of a mathematical model to support the assessment of AM social impacts.  
This paper is structured into six sections. The first section presents the problem description and the objectives of the research. In the second section, the theoretical background considered relevant to the development of this study is presented. In the third section, a SLCA framework is proposed to assess the social impacts of an AM product throughout its life cycle. In the fourth section, an exploratory case study has been carried out in order to validate the initial set of indicators proposed in the developed framework. In the fifth section, research implications, limitations, and future directions are discussed. Lastly, in the sixth section, the conclusions of the study are presented.