Accurate and rapid estimation of manufacturing costs can improve the competitiveness of manufacturers and optimize part design. Several factors affect the cost, including the part design model, machining processing progress, and materials. Extracting a unified dataset from the manufacturing information is complicated owing to different information expressions, such as geometrical-topological, digital, text, and symbol representations. This study proposed a manufacturing cost estimation method based on similarity. The main contribution of this study is the calculation of the similarity of manufacturing factors, particularly the similarity of 3D geometrical models: ① the geometrical-topological representations of a model was transformed into point cloud data and a point cloud similarity calculation method based on the implicit shape model was developed, from which the similarity of the 3D model of the part was obtained;② the manufacturing factors were transformed into digital representations and the similarity of these factors was calculated using Euclidean distance. The weights of these factors were determined using subjective weight coefficients and the similarity of the parts was obtained based on the weights. Finally, the manufacturing cost was estimated using the smoothing index method. The accuracy of the proposed method has a state-of-the-art effect compared to other methods.

Because of its cleanness, safety, explosion proof, and other characteristics, pneumatic technologies have been applied in numerous industrial automation fields. As a key controlling element of a pneumatic system, electric-pneumatic pressure proportional valves have attracted the attention of many scholars in recent years. In this paper, in order to illustrate the research status and the development trend of electric-pneumatic pressure proportional valves, firstly, several related technologies will be introduced, for example, simulation methods and experimental modes. In addition, controlling methods, structural styles, and feedback forms are also compared in several types of pressure proportional valves. Moreover, the controlling strategy, as a significant relevant factor affecting the efficiency of valves, will be discussed in this paper. At the end, the conclusion and worksof electric-pneumatic pressure proportional valves in the future will bediscussed to achieve the electrical integration.