中密度纤维板（MDF）的密度及其在线检控

【作者】 许俊；

【导师】 向仕龙；

【作者基本信息】 中南林学院 ， 木材科学与技术， 2002， 硕士

【摘要】 我国的中密度纤维板生产发展很快，根据95计划和2010年规划建设中的大中型中纤板项目计算，到2010年我国中纤板总生产能力将达450万m~3／a。但是我国的中纤板厂产品的质量，生产的成本，企业的效益等都存在一定的问题。主要表现在过分依赖进口，重复引进现象严重，对于进口线先进的技术没能很好地组织人员去消化吸收。另一方面国产设备在线检测与控制水平不高，制约了我国MDF的健康发展。解决生产规模与生产质量，产品档次之间的矛盾是广大林产工业科技工作者的责任。本论文在分析总结了国内外有关中密度纤维板生产线自动检测与控制方面的理论的研究成果和实际应用成果基础上，就MDF生产线的密度在线检测与控制做了专门的论述。在MDF中，密度是关键的一个工艺参数，其大小及分布特征很大程度决定了产品的物理力学性能及生产成本。而且密度并不是一个独立的因素，对于它的控制涉及了板坯含水率的控制，铺装工艺的控制，热压工艺的控制等。因此密度的控制是整个中密度纤维板生产线管理的核心内容。论文根据对中密度纤维板影响的实际因素，从影响中密度纤维板性能最明显的平均密度和剖面密度出发。介绍了它们的各自特点，影响因素及对于各个参数应进行的控制。同时，结合不同的机械设备讨论和分析了铺装线上的检测与控制技术，热压工段则根据设备与工艺的不同，将其分为多层间歇式热压，单层间歇式平压，单层连续式平压，分别详细论述了相应的检测与控制技术。最后介绍了对生产成品采用无损检测其平均密度和剖面密度的技术，与生产线设定的要求相互比较，由此观测和调控生产线的运行，为调节工艺参数提供依据，使整个生产线的在线检测控制更加完善。在分析讨论的过程中，在许多方面提出了自己的观点和设计思路，有些具体的问题从原理的角度给予了分析，比如程序的编制只列出了其编制原理图，并没有给出具体的程序，主要侧重于如何根据工艺编制相应的程序，如何用计算机的语言来描述工艺的变化。因为对于具体的生产线来说情况是千差万别的，这一部分工作可在企业进行相应技术改造时，在工艺人员的指导下由专门从事程序设计的工作人员来进行，本论文仅作理论上的探讨，并希望能对于实际从事人造板质量技术改造的工作人员提供理论参考。论文分析了多层热压机工艺参数的检测与位置—时间型热压曲线的控制原理和单层间歇式平压法控制系统的工作原理并设计出相应的工作主程序及部分子程序。我国目前正在开发连续平压法热压机，论文中配合这项工作，分析了有关参数控制的工作原理和实际应用。通过对密度参数控制的分析与总结，可以看出生产高质量低消耗的产品是一个涉及工艺参数相当多的复杂系统，要想将这项工作做好需要付出很大的努力。因此，在进行MDF企业技术改造和MDF生产设备的研制时，走适合于我国国情的发展道路是很关键的。我们必须从引进后消化吸收的角度出发，自主开发出适合我国国情的质量检控系统，从根本上解决我国人造板行业质量检控整体上落后的现状。更多还原

【Abstract】 Produce in Medium Density Fiberboard of our country has developed very fast. Calucated by large-middle model Medium Density Fiberboard in 95梡lan and 2010梡lan production capacity of Medium Density Fiberboard of our country will have 4.5 million m3/year by the end of 2010. But the quality of product, the cost of production, economic benefit of enterprise in Medium Density Fiberboard of our country lie some questions. It is dependent on import, imports foreign technology and equipment repeatly. Have no organized skilled personnel to digust and observe imports foreign technology and equipment. The other hand automatic control and examine of china-made equipment is poor. All of those hinder the development of Medium Density Fiberboard of our country. Solving the contradictary of produce scale and produce quality is due to the scientific and technical workers in forestry factory.In the paper, applied achievement and achievement in theory of automatic control and examine automatic control and examine in produce line of Medium Density Fiberboard were analysed and summared and a specialized discuss was gived. Density is a critical process parameter during the Medium Density Fiberboard. The physics and mechanics function of the product is detemined by the feather. And the density is not a sole factor, it relates the control of the mat of the moisture, the control of forming process, the control of the hot pressing curue. So the controll of density is the core of produce line the Medium Density Fiberboard. The paper devides two parts: average density and vertical density, and introdunces the characteristic of each other, the factor of influence and the control to each factor. Their characteristics according to different kinds of mechanical installation were Dicussed such as the characteristic of control technology in forming line, distinguishing them as multi - daylight press single opening flat hot - press, jingle - daylight press. At last, the technology of non - destructive test to product was introduced. It is can be forecasted that the automatic control and examine will make better on the line of the whole produce.During the analysing and discussing, some views were provded and some concrete conditons from the principle were analysed such as only devise the principle pictures on programming. Pay attention to using the compute language to describe technological process. The situation is different on the produce line. The examination of process parameter and the controll principle of location - time hot pressing curve were Analysed. The working principle of the jingle-daylight press was provided and the working main program and some sub program were devised. Single opening flat hot-press cannot be made in our country, so only analysing the working principle and summarizing the controll to density parameter. It is difficult to producing product of high quality and low consumption during the technical innovation in enterprise of Medium Density Fiberboard. So it is critical to develop producing mechanical instauations according to the condition of our country.The backward condition in technique of wood base pannel of our country is not solved only by blind importing foreign technology and equipment.更多还原