普通机床如何改造成数控机床

摘要

针对大多数企业，具有数量众多和较长使用寿命的普通机床，其加工精度较低、不能批量生产，自动化程度不高，自适应性差，但考虑投资成本，产业的连续性，又不能马上被淘汰，购买新的数控机床是提高产品质量和效率的重要途径，但是成本高，许多企业在短时间内无法实现，这严重阻碍企业设备更新的步伐。企业要在激烈的市场竞争中获得生存、求得发展，就必须在最短的时间内以优异的质量、低廉的成本，制造出合乎市场需要的、性能合适的产品。为此改造现有旧机床、配备与之相适应的数控系统，把普通机床改装成数控机床，不失为一条投资少、提升产品质量及生产效率的捷径，是当前许多企业对现有设备更新换代的首选办法，也是提高机床数控化率的一条有效途径。

改造后的车床属于开环控制。由于开环系统自身固有的缺陷不容易保证加工精度。因此，合理选择伺服系统是课题的一个中心环节。步进电机工作原理特性和实际应用正好符合我们的这一需求，所以，改造系统选择步进电机作为双向进给驱动电动机。步进电机是一种通过电脉冲信号控制相绕组电流实现定角转动的机电元件，与其他类型电机相比具有易于开环精确控制、无积累误差等优点，在众多领域中获得了广泛的应用。为了得到性能优良的控制结果，出现了很多步进电机控制系统，其中采用单片机作为控制核心的控制系统得到了广泛的应用。很多这种控制系统在步进电机的驱动上已经做的非常好，本文采用的控制电路主要由8031单片机、晶振电路、地址锁存器、译码器、EEPROM存储器及可编程键盘／显示控制器Intel一8279等组成，单片机是控制系统的核心。文中对整个系统的架构及硬件电路和驱动软件的实现都做了详细的设计。

本设计在对原有机床机械机构、性能、功能等进行充分研究基础上，主要针对中小型普通车床控制系统进行改造，用单片机系统实现弱电控制强电机，改造了系统的切削工艺，提高了切削精度和效率，对旧车床的数控改造有一定的指导作用，是一种新的尝试，也必将有更加广阔的应用前景。

关键词：数控化、自动控制、步进电机、自动刀架。

ABSTRACT

Most enterprises still have large amounts general—purpose machine tools which have longevity of service，low precision, can’t adapt to mass production，low automatization and adaptability, but call not be washed out because of its low cost and continuity of enterprise’S production. Purchase of new CNC machine tools is to improve product quality and efficiency of an important way, but the costs are high, many companies can not be achieved in a short time, which seriously hindered the pace of business equipment updates. Enterprises in the fierce competition in the market to survive, and seek development, it must in the shortest possible time and with excellent quality, low cost, to create a line with market needs, performance, the right products. To this end reform the existing old machine, equipped with suitable control system, converted into the ordinary CNC machine tools, after a small investment, improve product quality and production efficiency of the shortcut, many companies are currently upgrading of existing equipment Preferred option, but also improve the rate of CNC machine tools is an effective way.

After transformation, the lathe is open-loop control. Because the inherent open-loop system is not easy to ensure accuracy flaws. Therefore, a reasonable choice servo system is a central part of the subject. Characteristics of stepper motor principle and practical application of this just to meet our needs, so the reform the system chosen as the bi-directional stepper motor feed drive motor. Stepper motor is controlled by electrical pulse signal phase rotation angle of winding current to achieve given the mechanical and electrical components, compared with other types of motor control with easy-to-open-loop precision, no accumulation of errors, etc., in many fields to obtain a wide range of applications. In order to obtain good control performance results, there has been a lot of stepping motor control system, which uses single chip as the control of the control system has been widely used. Many of these control the stepper motor drive system has been doing very well, in this paper, the control circuit mainly by 8031, crystal oscillator circuit, the