Ball screw is the key parts of NC machine, precise instrument and many kinds of mechanical devices. Whirlwind milling is a new and effective thread manufacture technology. This article studies the internal heat conduction equation of whirlwind milling ball screw based on Heat Transfer, calculates ANSYS simulation result. The simulation results show that the surface temperature distribution rule and internal temperature distribution rule of a ballscrew is consistent. The article analyzes the influence factors of the thermal elongation. It provides a basis for compensating the thermal deformation error of whirlwind milling ballscrew.

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In order to improve the interfacial bonding between graphene and copper and improve the dispersibility of graphene in the copper matrix, a novel method was used to prepare graphene. Firstly, graphene oxide (GO) was prepared by the modified Hummer's method, and then the reduced graphene oxide-supported cobalt nanoparticle composite powder (Co@RGO) was prepared by one-step in-situ reduction method. The fabricated materials were mixed with copper powder to obtain various volume fractions. The powder mixture was subjected to compression and discharge plasma sintering (SPS) to prepare a bulk copper-based composite material. The microstructure and its comprehensive properties were studied by SEM, TEM, XRD, FTIR and Raman. The results show that the agglomeration of graphene can be effectively inhibited after the cobalt nanoparticles supported on the graphene surface. The proper amount of Co@RGO could be uniformly dispersed in the copper matrix. The composite material showed a high electrical conductivity (>86% IACS), and the Vickers hardness also increased by about 30% compared with pure copper.