Abstract: To improve the linearity of rotary synthetic carbon film potentiometer,the technology of trimming carbon film was adopted.The software of trimming system was developed through Visual Basic 6.0.According to the voltage jump at the zero of the rotary synthesis of carbon film potentiometer,a kind of unidirectional zero-search algorithm was designed after analyzing the influences to data acquisition brought by mechanical hystersis of the brush.The target slope approaching method was proposed to determine the target line.In addition,the methods of reserving trimming angle and adjusting cutter incidence were proposed,and the trimming experiment was carried out.The experiment results showed that the error of zero-search had been decreased a lot compared with bidirectional zero-search.The methods of reserving trimming angle and target slope approaching could improve linearity of potentiometer and qualification rate.The trimming system was stable and reliable,and the proposed trimming technology had reached the demands of precision potentiometer linearity.

Key words: synthetic carbon film potentiometer, linearity, trimming carbon film, zero-search, target line, precision machining

摘要： 为提高回转式合成碳膜电位器的线性精度,采用修刻碳膜的工艺方法使涂覆的碳膜材料在电位器内壁上分布更均匀。基于Visual Basic 6.0设计了自动化修刻系统软件;分析了电位器修刻时电刷的机械滞后对电压采集的影响,结合电位器的零位电压值跳跃特性,设计了单向搜零算法;提出了目标斜率逼近法,并由该方法确定了修刻目标直线;提出修刻角度保留法和调整刀具倾角法,并进行了修刻实验。实验结果表明,相比双向搜零,单向搜零的搜零误差大副减小;采用目标斜率逼近法和修刻角度保留法修刻,提高了电位器的线性精度,同时也提高了产品合格率。修刻系统稳定可靠,提出的电位器修刻技术达到了精密电位器线性精度要求。

关键词: 合成碳膜电位器, 线性精度, 修刻碳膜, 搜零, 目标直线, 精密加工