Search results

The purpose of this paper is to describe the stability and properties of the direct metal laser fabrication (DMLF) process, by putting forward top surface quality (TSQ), which could be a unique and crucially important feature compared with traditional manufacturing methods.

Through the systematic and detailed analysis of DMLF process using related theories of additive manufacturing technologies, it was revealed that TSQ was the key factor for controlling the stability of DMLF process and thus tailoring final properties of metallic parts. Only good TSQ can ensure the stability of DMLF process and excellent performance of metal parts in theory.

TSQ was defined as the surface morphology in macro and micro scopes in laser scanning area of unit layers during DMLF, and could be characterized by three key elements: flatness, compactness and cleanliness. The flatness was the significant factor to assure the shaping during DMLF, while the compactness and cleanliness were the decisive factors to assure the final properties of metal part for DMLF. As an example, the typical top surface defects and their contributing factors in DMLF for Cu‐based metal powder mixtures were investigated thoroughly according to the proposed definition and requirements. Moreover, the specific controlling methods of TSQ were provided and discussed. Eventually, DMLF of three‐dimensional Cu‐based metal sample with complicate structure was successfully performed by taking some effective measures for adjusting TSQ parameters.

Few comprehensive investigations have been carried out on this topic. The definition and evaluation methods of TSQ for DMLF have been introduced for the first time in the present paper.

Worker cooperative practitioners and developers often claim that democratic worker ownership advances egalitarianism within and beyond the workplace, but most of the empirical evidence in the USA is based on ethnographic case studies or small-scale surveys. This study aims to leverage the first national survey about individuals' experiences in these unique firms to test for the presence of inequalities by gender, race and immigration status in the broader sector.

The study uses a 2017 survey comprising a sample of 1,147 workers from 82 firms. This study focuses on measures of workplace benefits that capture material and psychological ownership, wealth accumulation, wages, workplace autonomy and participation in governance. This study uses ordinary least squares regression models with fixed effects alongside pooled models to determine the effects of gender, race, immigration status and the intersection of gender and race on these outcomes, both within and between firms.

This study finds no evidence of wage gaps by gender, race or immigration status within worker cooperatives, with job type, tenure and worker ownership status instead explaining within-firm variation in pay. Still, this study documents sector-wide disparities in material and non-material outcomes by gender, race and immigration status, reflecting differences in individual-level human capital and job characteristics as well as widespread occupational segregation and homophily.

The paper offers a novel contribution to the literature on workplace empowerment and inequality in participatory firms by analyzing race, gender and immigration status in the most robust dataset that has been collected on worker cooperatives in the USA.