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The objectives of this paper are to estimate the annual Malmquist TFP(total factor productivity) index of Korea and China’s road freight transport with DEA(data envelope analysis) and to decompose the index into technical efficiency change and technology change. In the process of the estimation, we used labor, capital, and fuel as input factors and ton-km of road freight transport as output factor. The panel data of Korea and China’s road freight transport industry from 1985 to 2004 are used. The results of the analysis show several points. First, there was no significant improvement in China’s TFP growth before 1997, but there was continuous growth in TFP since 1997 because of constantly increasing domestic freight transport demand. Second, there was downward trend in Korea’s TFP, especially there was a large reduction of productivity in 1998 because of the huge reduction of road freight transport demand during the period of the economic crisis. Third, the technology improvements play a significant role in the TFP growth and the technical efficiency had negative effects on the TFP growth of Korea. However, the technology improvements as well as the technical efficiency had positive effects on the TFP growth of China’s road freight transport industry.

The purpose of this study is to cover the influence of selected printing parameters at a macro and micro-geometrical level, focusing on the dimensions, geometry and surface of printed parts with short carbon fibers reinforced PLA. For this case study, a hollow cylindrical shape is considered, aiming to cover the gap detected in previous works analyzed.

Nowadays, additive manufacturing plays a very important role in the manufacturing industry, as can be seen through its numerous research and applications that can be found. Within the engineering industry, geometrical tolerances are essential for the functionality of the parts and their assembly, but the variability in three-dimensional (3D) printing makes dimensional control a difficult task. Constant development in 3D printing allows, more and more, printed parts with controlled and narrowed geometrical deviations and tolerances. So, it is essential to continue narrowing the studies to achieve the optimal printed parts, optimizing the manufacturing process as well.

Results present the relation between the selected printing parameters and the resulting printed part, showing the main deviations and the eligible values to achieve a better tolerance control. Also, from these results obtained, we present a parametric model that relates the geometrical deviations considered in this study with the printing parameters. It can provide an overview of the piece before printing it and so, adjusting the printing parameters and reducing time and number of printings to achieve a good part.

The main contribution is the study of the geometry selected under a 3D printing process, which is important because it considers parts that are created to fit together and need to comply with the required tolerances. Also, we consider that the parametric model can be a suitable approach to selecting the optimal printing parameters before printing.