摘要
传统的齿轮模具型腔电铸方法存在着许多问题,如:铸层质量差、沉积速度低、铸层厚度分布非常不均匀,严重时某些局部无金属沉积,不适用于小模数齿轮模具型腔的制造。分析认为,这些弊端主要是阴极上电流密度分布不均匀所致。本文在进行试验研究后,提出了一种新的齿轮模腔电铸成形方法。这种方法采取特殊的电极配置方式,用一绝缘材料齿轮对平板阴极进行选择性屏蔽,从而获得所需形状的铸层。这一方式保证了阴极上电流密度均匀分布,铸层无任何尖角缺陷、均匀致密。采取的强烈冲刷、脉冲供电等措施更进一步提高了沉积速度和铸层质量。这种方法既可用于直接电铸镍模具型腔,也可用于电铸电火花加工模腔用铜电极。已经采用了这种方法制造了模数在0.25～0.40mm之间的齿轮模具型腔近百个,均获得满意结果。
Conventional electroforming of gear wheel moulds suffers from serious corner weakness, low deposition speed,especially for the gear wheels with small moduls. The weakness is resulted from the unevenness of current field distribution on cathode. Based on the analysis of electric field between electrodes and on a lot of tests, this paper presents a new method of electroforming gear wheel moulds in which the electroformed layer can be obtained at high speed without corner weakness anywhere. In this method, the gear master model made of non-conducting material is located on a stainless steel plate which is connected with the negative of the power supply. Metal ions are deposited on the plate and a metal layer is gradually formed. It is noticeable that the electric current density is almost the same everywhere on 'the cathode and so no corner weaknesses are observed. In addition, strong flushing of electrolyte over cathode and special pulse power supply improve the current density and generate a dense electroformed layer. The present method can be used to produce both mould cavity parts and electrodes for EDM gear moulds. It has succeeded in producing many gear injection moulds. gears,mould cavities,electroforming,electric field distribution,electrode
基金
国家自然科学基金
