摘要随着工业自动化技术和计算机技术的不断发展，以及塑料制品涉及范围的不断深入， 塑料挤出生产中挤出技术也逐渐变得日益完善和创新。塑料挤出机是塑料挤出加工的重 要设备，目前大部分的塑料制品都是由塑料挤出工艺加工完成的。而在我国传统的塑料 挤出生产中，没有计量加料控制，一般是由有经验的操作工人凭自己的感觉调节原料之 间的比例，但是这种人工控制的办法精度极不稳定，如果控制得不及时，这不但会加大 工人的劳动力度，而且对产品的质量影响非常大。83507

本课题总结了前人课题研究的一些成果，从经济实用性的角度出发，设计了塑料挤 出生产中的计量加料控制系统方案。采用可编程控制器实现对加料阀的自动开关，即通 过设置料斗内物料的上下限，当物料低于下限时，控制加料阀开启，向料斗内加入物料； 当加入的物料达到上限时，关闭加料阀，停止加料，如此循环。本控制采用西门子公司 的软件 step7 Micro/WIN 进行编写程序，通过软件对编写的程序进行仿真，以此来验证本 课题的研究的有效性。

经过在编程软件中仿真调试后，实现了对计量加料系统的自动控制，并在一定程度 上降低了人工劳动力，提高了整个生产线的经济效益。

毕业论文关键词：塑料挤出机，自动控制，可编程控制器，计量加料系统

Abstract With the continuous development of industrial automation technology and computer technology, as well as the deepening of the plastic products range, in the production of plastic extrusion extrusion technology has become increasingly perfect and innovation。  Plastic extruder is one of the important equipment, plastic extrusion processing at present most of the plastic products are made of plastics extrusion processing technology。 In the traditional plastic extrusion production in our country, without measuring feeding control, usually by an experienced operator by our own feeling to adjust the ratio between the raw material, but the way of the manual control precision is unstable, if the control is not timely, it will not only increase the intensity of labor, and very big influence on the quality of the product。

This topic summarizes some predecessors' research results, from the perspective of economic practicability, designed a measuring feeding control system in plastic extruding production plan。 Adopts programmable controller to realize automatic switch of charging valve, namely by setting the hopper in the material on the floor, when the material is less than lower limit, control the charging valve open, add material inside the hopper; When joining material to limit, close the charging valve and stop charging, so cycle。 The control  software  adopts Siemens step7 to write programs, Micro/WIN through software simulation was carried out on the program, in order to verify the validity of this topic research。

After the simulation debugging in the programming software, realized the automatic control of the metering feed system, and to a certain extent, reduces the manual labor, improve the economic benefits of the whole production line。

Keywords: plastic extrusion machine, automatic control, programmable controller, metering charging system

目 录

第一章 绪论 1

1。1  课题研究的目的和意义 1

1。2  研究现状 2

1。2。1 国外研究现状 2

1。2。2 国内研究现状 2

1。2。3 存在的问题 2

1。3  课题的主要研究内容