Design of Heat Exchange System of Sand Core Drying Furnace

Heat exchange system is a circulatory drying system on sand core drying furnace. However, there are some shortcomings in the heat exchange system of sand core drying furnace in the current industrial field. For example, the temperature in the drying process is not stable enough, and the optimal temperature control parameters are difficult to choose. In this study, a proportional regulating heat exchange system is designed. The system adopts SIMATIC 1200 programmable logic controller as controller, motor-driven control valve as actuator and back propagation neural network proportion integral differential control algorithm. After sand core drying test, the results revealed that the proportional regulating heat exchange system can realize automatic control of sand core drying temperature and output the optimal combination of heat exchange system control parameters. Compared to the previous heat exchange system, it has better drying temperature control stability.

Research on Stability of Sand Core Handling Robot System Based on PID Control

When an industrial robot uses a gripper with half hardness and flexibility to carry a hollow sand core, mechanical vibration will cause the gripper to grasp the sand core unsteadily or cracks in the sand core due to excessive pressure. In this paper, the mathematical model is constructed based on the elements such as gripper structure, clamping pressure and mechanical vibration, the system stability is analyzed, the PID controller is added for correction, the parameter values of Kp, Ti and Td are set by Ziegler-Nichols method, the transfer function of PID controller is obtained, and then the corrected system function is calculated. The dynamic response performance of the system is simulated and analyzed by Matlab / Simulink, the parameters in the PID controller are adjusted, and the overshoot of the system is reduced from 85% to 25%, which effectively reduces the impact of mechanical vibration interference on the sand core and realizes the optimal control of the system.

Study on the Influence of Sand Core Compactness on Surface Entropy considering Engineering Disturbance

In order to explore the correlation between the compactness of sand core samples and its surface image features and to provide the basis for rapid identification and recognition of core samples in engineering investigation, a typical image data set of sand core samples disturbed by drilling construction in practical engineering has been established, using Python language to compile algorithm to calculate one-dimensional entropy and two-dimensional entropy of 60 groups of sand core samples with different densities. The influence of different sand core compactness on surface entropy characteristics was discussed, and the following conclusions were obtained: (1) Affected by drilling construction and disturbance, the looser the sand core surface particles are, the worse the sorting is and the more irregular the shape characteristics are. There is a close relationship between grain texture and compactness. (2) The calculation results of sand image entropy of one-dimensional entropy and two-dimensional entropy showed that the entropy value of loose, slightly dense, and medium dense sand images is positively correlated with the compactness of sand. (3) The maximum variance of two-dimensional entropy of loose, slightly dense, and medium dense sand image in the same borehole is less than 0.09, and the data variance amplification effect of two-dimensional entropy of image is mainly between different boreholes. (4) The dense feature of core sample structure forms an ordered structure with a gray change boundary, which increases the roughness of the image and leads to the increase of entropy. The two-dimensional entropy reveals the internal correlation mechanism of the influence of the engineering state on the surface structure of sand more clearly than the one-dimensional entropy and more effectively characterizes the dense degree of sand particles. (5) Using two-dimensional entropy to judge the compactness of sand image in the same borehole, the data fluctuation is small, and the algorithm is stable and reliable. The research results have reference values for the detection and analysis of sand sample density in geotechnical engineering investigation.

The first casting mould for a ‘Syrian Bottle’ from Lipnik, Bulgaria

The following article presents the first mould ever discovered for casting a so-called “Syrian Bottle”, a distinctive vessel type that originated in Mesopotamia around the mid 3rd millennium BC and soon after spread to Anatolia, the Aegean and Southeast Europe, as imports and local derivatives. A few examples were made from precious metals and lead, the most notable one being a golden globular bottle, part of “Priam’s” Treasure A” from Early Bronze Age Troy. The mould from Lipnik seems to have been intended for the production of small metal bottles of ‘Syrian’ shape, and supportive agents like a green sand core applied for the production of such a complex item. The mould, however, was obviously never used. A review of associated manufacturing details like pegholes, riser and vent show that although these features were particularly prominent in the 2nd millennium BC, moulds from earlier (Anatolian) contexts do possess such characteristics as well. This currently unique, locally produced example is therefore dated to the latest 3rd or earliest second millennium BC, coinciding with ever-growing interaction between distant cultural entities stretching from Mesopotamia to Southeast Europe and beyond, and allowing for the exchange of ideas, fashions and technologies.

Improving the Quality of Production of Sand Core on Core Shooting Machines

The article is devoted to the study of the method of modeling the core shooting process of manufacturing core from cold hardening mixtures (CHM) in the software package Flow-3D, as well as consideration of recommendations on the parameters of the core shooting process, to ensure quality castings of cast iron and steel. This technology of production of cores belongs to technologies which are widely used in foundry production.