共查询到20条相似文献，搜索用时 31 毫秒
1.
树种和含水率对纵截圆锯锯切指标影响的试验研究 总被引：1，自引：0，他引：1
为研究树种和含水率对纵截圆锯切削力、锯切功率和锯切比功等锯切指标的影响关系,笔者选择我国东北小兴安岭地区常见的9种树种,在恒定切削速度和进给速度的条件下进行了对比试验。一、试材试材选择小兴安岭产鱼鳞松 相似文献
2.
ABSTRACTThis paper investigates the effect of rotation speed and vibration response of a circular saw on the sawing process of Douglas-fir wood. An idling test was conducted on a guided circular saw to determine its stable operation speeds and vibration behavior. Short-time Fourier transform analysis was performed on saw idling test data, and variation of excited frequencies of the blade as a function of rotation speed was obtained. The saw blade critical speeds and the rotation speeds that correspond to saw flutter instability were identified. Then experimental cutting tests were conducted at different cutting conditions and the effect of rotation speed and saw vibration response on cutting power consumption and sawing accuracy was investigated. The results showed that conducting a saw idling test and vibration response analysis can identify the saw critical and flutter speeds, which is essential for identifying the optimum rotation speed of circular saw. There was a significant increase in power consumption when cutting at super-critical and super-flutter speed. The effect of rotation speed on sawing accuracy is complex and nonlinear. This effect interacts with feed speed, which makes it difficult to generalize sawing accuracy versus rotation speed in the circular sawing process. 相似文献
3.
Vahid Nasir 《Wood material science & engineering》2020,15(1):1-16
ABSTRACTSawing is the most common machining process and is present in both primary and secondary wood transformation sectors. The objective of this paper is to review how it is affected by different factors. The current challenges associated with various machining factors, process monitoring, and sensor selection were identified and explained. Consequently, four research challenges and technological gaps were outlined. (1) Contradictory results have been reported due to different cutting processes, wood species, measurement methods, and cutting speed range studied in literature, so special consideration needs to be taken when comparing results with those available in the literature. (2) Laboratory test conditions cannot yet fully represent the extreme cutting conditions in sawmills. More emphasis should be placed on those harsh industrial cutting conditions. (3) Research on wood cutting lacks multi-objective optimization approach, which suggests that sawdust generation should be simultaneously analysed with surface quality and power consumption. (4) Compared with metal cutting, little research has been conducted on wood sawing monitoring using an artificial intelligence approach, which should be prioritized in designing adaptive control systems. Combining intelligent monitoring and multi-objective optimization approaches should pave the way for controlling the sawing process so higher surface quality and cost efficient machining is achieved. 相似文献
4.
The experimental results of orthogonal cutting of maple and the modeling of the cutting mechanics are presented. The tool cutting forces were measured for different feed rates. A set of equations relating the tangential and feed forces to the tool edge width and feed rate (chip thickness) to calculate the chip and edge cutting force coefficients was developed. Then the chip force and edge force coefficients were calculated from experimentally obtained cutting forces and were plotted in a polar-coordinate system with respect to the fiber orientation of the maple disk. The polar-coordinate presentation of the cutting force results and the calculated cutting force coefficients provides an excellent visual appreciation of the relation between the cutting forces and the wood fiber orientation. Chips were also collected from various sectors of the wood disk. This analysis further identified the effects of fiber orientation and cutting forces on the types of chip formed and hence the cutting mechanics involved. By applying the calculated cutting coefficients for each tool orientation (in respect to the grain) it is possible to predict the feed and tangential forces for any feed rates. There is good agreement between the predicted and measured cutting forces. 相似文献
5.
Jin Weizhu Kong Degang Northeast Forestry University 《林业研究》1991,2(1):108-112
Oblique cutting of wood is an important form of cutting wood.With the developingof woodworking industry,it is widely used in wood machinary processing such as planing,milling,sawing,drilling and so on.This paper takes oblique planing and helix milling of wood as examples.The influences of bevel angle and other factors on the cutting force have been shown.The changingrules of cutting forces have been summarized.On the basis of it,we especially carried out theoreticalanalysis on the changing rules of cutting forces and discussed the influence of the changing rules onpractice. 相似文献
6.
为解决实际生产过程中削片机切削能量损耗大、功率不匹配和生产效率较低等问题,基于断裂力学理论和Ⅰ、Ⅱ、Ⅲ型混合模态断裂准则,以及年轮对木材断裂的影响,将刀具旋转切削的动力学问题转为对木料的断裂分析。通过对木料在切削过程中的受力分析,确定裂纹扩展模型,构建了力学模型,推导并研究了切削力与各切削参数之间的关系;借助MATLAB软件建模分析切削角、木料半径和切削厚度与切削力的关系,得到切削角θ=π/4,裂纹极角φ=2π/5时,切削能耗较优。 相似文献
7.
本文介绍了热平整技术的理论基础和滚筒热平整技术。采用热平整和辊压的方法 ,木材受热后表面的绒毛状纤维被塑化而固定 ,木材表面变得密实和光亮 ,且没有粉尘 ,有望替代现在的砂光工序。文章还介绍了在电加热平整中 ,把平整工具置于锯切工具后 ,利用锯切工序后产生的切削热平整家具的加工表面和侧面。试验发现高频机械振动和超声波平整不同材料的效果良好 ,因其具有宽广的频域和功率的调整量范围 ,可望广泛应用于多种场合 相似文献
8.
11种针叶树材的切削厚度、刀具前角和木材含水率对切削阻力影响的研究 总被引：3，自引：0，他引：3
对11种针叶树材在0-90、90-0和90-90三个切削方向的高速直角自由切削的试验研究表明:1)切削厚度、刀具前角和木材含水率对主切削力影响的基本趋势,各树种基本一致,但定量考察有一定的差异;2)三因素影响的阻力比值R_t、R_a和R_w在不同树种中变异不大;3)三因素对切削阻力的影响存在一定的交互作用,在不同切削方向,情况有所不同。 相似文献
9.
Among the machinery found in wood manufacturing industries, routers and planers are the most commonly used. These tools, which many times are mounted on metal cylinders, actually operate only briefly, i. e., when a chip is cut from a piece of wood under process. The rest of the time the knife follows the cylinder surface and a cycloid is formed relative to the work piece, which in turn is fed into the machine. A number of knives are mounted on the cutter, which ascertain that the planed surface will become sufficiently planed and does not show too a wavy pattern. This works fine for high revolutions and low feeding speeds even if problems sometimes occur. Factories, however, naturally want to increase the overall manufacturing speed, which means that at the same time more defects are introduced at the planed surface. These defects are the result of the cutting process. In this paper, we examine, by use of a load cell, how the cutting forces vary during the formation of a wood chip. Wood is not an isotropic material and knots and other anomalies make the evaluation harder. In order to simplify the conditions, experiments are also shown from the cutting of a plastic polymer material as well as Medium Density Fibreboard (MDF). It is shown that the work piece vibrated intensely which littered all output data from the cell. Experience from the experiments however made it possible to design a computerised filter which saved only those registrations which were of interest while the others were set to zero. For beech, the forces were found to be of the magnitude 50 N/cm opposite to the feeding direction while the tranverse forces changed signs and had a magnitude of about 5 N/cm. 相似文献
10.
不同树种木材切削阻力变动模型 总被引：4，自引：1，他引：4
根据１１种针叶树材和１５种阔叶树材切削阻力的研究结果，推出不同树种木材主切削力变动模型，描述不同树种木材切削阻力在不同切削条件下变动的规律，并可对此种变动进行估计。模型由三部分组成：不同条件下切削阻力的平均水平；不同树种中切削厚度、刀具前角和木材含水率对切削阻力的影响；不同条件下木材密度与切削阻力的关系。 相似文献
11.
针对传统板材锯切设备大多数处于半自动化状态,且存在加工精度低、出材率低、安全性差等缺点,笔者提出一种用于毛边板材裁边的纵剖优选锯设备的主轴调整系统。通过对毛边板材的裁边工艺进行分析,利用三维软件对纵剖优选锯主轴调整系统结构进行实体建模,确定了纵剖优选锯主轴调整系统的总体结构。对主轴组件上的锯片切削力和切削功率进行详细的设计计算,完成了主轴调整系统的主轴组件、锯片调整组件等结构的设计研究。根据锯片滑台最大许用应力和最大变形量对其进行有限元静力学仿真分析,通过仿真结果校核得出的锯片滑台满足设计要求。设计的纵剖优选锯主轴调整系统结构具有适用于产品多规格、高出材率、高自动化和实用性强的特点。 相似文献
12.
13.
孟庆午 《林业机械与木工设备》2008,36(9)
简述木材锯切技术所经历的手工期、简单机械期、近代期和现代期及其特点,对各种木材锯切技术进行了分析,结论是零锯料角木工锯子技术整体性能较好,可以实现高质量、高效率、高效益锯切木材. 相似文献
14.
以榆木、杨木和松木为试验材料,采用不同的测试模式、木材切面、放大倍数和切削加工方式对切削表面粗糙度进行测定评价,比较分析上述因素的影响。结果表明:测定模式对于粗糙度值有一定影响;同一树种、同一切面时,磨削表面粗糙度明显低于锯切和旋切,表面粗糙度值为锯切>旋切>磨削;榆木磨削加工中,显微构造明显部位的三切面粗糙度值为径切面>弦切面>横切面;放大倍数与木材显微构造有关,对表面粗糙度值有影响。基于试验结果提出,木材切削表面粗糙度测定评价宜采用先选定被测试件的评价部位,再确定满足精度等级的测试模式的两步法进行。 相似文献
15.
Summary Slow speed wood cutting tests were carried out in which cutting forces were measured as a function of applied tool-work electrical potential. The cutting tool and workpiece were electrically insulated so that there was no current flow. Applied potential had no discernible effect on the cutting forces measured in the cutting of unextracted and extracted wet wood. 相似文献
16.
Summary This paper investigates a method for slicing thick pieces of wood across the grain using a sharp steel knife, and it demonstrates the effectiveness of the knife slicing process at an experimental level. In order to highlight the key parameters facilitating or hindering the thick slicing process, several factors affecting the cutting forces and the cut surface quality have been studied; the blade geometry, the effect of friction, the cutting speed, the boundary load constraints and the wood moisture content. The results indicate that a large proportion of the cutting force may be related to the wedging action of the blade in the wood. Therefore, significant reductions in the cutting energy can be achieved by optimising the blade shape. A simple homogeneous strain model has been developed which quantifies the cutting forces in terms of the blade angle and the blade surface friction. The results from this theoretical model are compared with the experimental findings and discussed in relation to methods for improving the cutting technique.This work was funded by the Foundation for Research Science and Technology. This support is gratefully acknowledged 相似文献
17.
木材损伤断裂与木材细观损伤基本构元 总被引：2，自引：1，他引：2
木材承载时细观结构上的损伤会在木材中扩展,并且损伤和缺陷在载荷下的演化行为决定着木材的宏观力学行为.木材的细观损伤基元可以归纳为4类:1)胞、壁层间界面损伤;2)细胞壁屈曲与局部塌溃损伤带;3)微孔洞损伤与汇合;4)微裂隙损伤(区).追踪分析木材从变形、损伤到断裂破坏的全过程,探明微结构演化与宏观行为关系,有助于揭示木材破坏的机制,并从中获得新的木材构造与其强韧功能相互关系的认识,对研发能够克服木材缺点、具有特殊强韧性能的新型木基复合材料具有重要指导意义. 相似文献
18.
红松水曲柳木材密度与切削阻力关系的研究 总被引：3，自引：1，他引：2
本文继前一报告之后,对红松、水曲柳木材密度与切削阻力的关系做了进一步的研究。主要的结果是:(1)木材密度与切削阻力的关系因树种、切削方向、切削厚度、刀具前角和木材含水率之不同而有差异;(2)切削厚度、刀具前角和木材含水率对密度与切削阻力关系的影响有统一的趋势,而且此趋势可用简单的线性关系表述;(3)木材中密度以外的影响切削阻力因素的分布状况,从株内较大范围看,半径和树高方向不同部位间均未表现出显著差异。 相似文献
19.
In this paper we focused on the differences of mechanical properties of tension and normal wood of 1-year-old poplar trees, artificially tilted. Elastic and fracture properties have been measured and linked to the anatomy. Tension wood is well known because it prevents good surface finishing and leads to difficulties with sawing. We studied three main mechanical properties: young modulus, energy of cutting and longitudinal residual strain of maturation (with strain gauges) because of their importance in wood technology. Moreover, this work takes place in a larger project of study, the phenomena of axes re-orientation in trees (allowing by the production of reaction wood), where these data are required for biomechanical modelling. The results show that tension wood has a higher young modulus, needs a higher energy to be cut and exhibited a higher level of longitudinal residual strain of maturation than those of normal wood. The results suggest that these differences require deeper analysis of the wood than anatomy: measurement of microfibril orientation in the S2 layer and also the lignin composition in monomeric units. 相似文献
20.
Summary A study was made of relationships between wear (loss of metal) and blunting (reduced performance) of the corner of a steel cutting tool turning a work-piece of hard fibreboard. Rake angle, clearance angle and surface preparation (grinding, polishing) were varied and measurements made were the three cutting force components and various wear parameters. It was confirmed that retraction of the edge from its initial position is not a satisfactory index of blunting and that the shape parameter corresponding to compression of the cut surface (negative clearance) was most influential. Also, for the particular tool and work-piece materials used and in the practical range of bluntness, the ratio of negative clearance to the width of the back wear land, as measured parallel to the cutting plane, was roughly constant. It is evident that development of a hard, very thin layer on the back face would minimize negative clearance and extend sharpening life. In the practical range for cutting wood and wood-based materials, clearance angle had a relatively small effect on the rate at which negative clearance and cutting forces increased, and rake angle had negligible effects. It is concluded that these angles should not be increased without taking into account factors other than blunting. Polishing considerably decreased blunting rate, especially of the tool corner, which is especially important in sawing. The expense of polishing may be justified in some exacting operations. 相似文献