切削速度对圆锯机锯切指标影响规律的研究

圆锯机是木材加工生产中广泛使用的机械设备之一.切削力(P)、锯木功率(N)、锯木生产率(S)、锯切比功(K)既是衡量圆锯机性能的指标,又是设计圆锯机必须考虑的参数.上述锯切指标受许多因素影响,其中切削速度是影响锯切指标的主要因素之一.在进给速度和进给力不变的条件下进行试验,通过试验,找出切削速度(U)对纵剖圆锯机锯切指标的影响规律.     

锯料角影响锯切表面粗糙度机理三探

文章首先以圆锯为例进行分析，在其它条件相同时。不论是减少锯齿数。或者是提高进给速度，还是在减少锯齿数的同时提高进给速度。只要相应地减小锯料角。锯切表面粗糙度就不变。并且推导出了相应改变的锯料角的计算公式。接着，文章直接给出了相同情况下的带锯及框锯的计算锯料角的公式。文章在最后结论中指出：减小锯料角是提高锯切效率而又不降低锯切表面粗糙度的办法之一；同时。也为降低锯子的制造成本和使用费用提供了新的途径。     

木材切削加工原理和设备(六)——第二讲 制材机械 第三章 制材

一、制材的基础 1.锯齿的锋利度锯齿的锋利度对于锯齿所受到的锯切阻力、锯切所耗能量、制材效率(锯解时可能达到的最大进给速度)和板材表面质量等都有影响。齿形角度和锋利度(锯切功率)之间的关系如图1和图2所示。     

环形金刚石线锯切割大理石试验研究

选用环形电镀金刚石线锯切割大理石,分析了锯丝线速度、工件进给速度和锯丝张紧力对大理石表面加工质量的影响,研究了金刚石锯丝的磨损机理。结果表明：工件进给速度对大理石表面粗糙度的影响最大,锯丝线速度对大理石表面粗糙度的影响次之,锯丝张紧力对大理石表面粗糙度的影响再次之。在本试验参数范围内,最优工艺参数为：工件进给速度为10mm/min,锯丝线速度为30m/s,锯丝张紧力为100N。     

双齿轮卷绕防叠机构的分析与综合

本文论述了双齿轮卷绕防叠机构的工作原理;以倍捻机卷绕机构为例,计算了机构输出运动的位移、速度和加速度曲线,描绘了机构的运动特性;并讨论了机构的约束条件,给出了偏心距、杆长比,扇齿轮摆角和齿数比等设计参数的选择范围,为机构的设计提供了依据。     

基于Profibus总线的金属切削带锯床数控锯切系统研究

由于金属切削带锯床锯切的过程中锯架受力不平衡,致使锯切精度与锯切效率较低,导致了待切削金属锯料的浪费,文章设计基于Profibus总线的金属切削带锯床数控锯切系统,硬件部分设计了自动夹件模块定位夹取金属锯料,选取斜向分齿的标准齿双金属锯条作为切削工具,软件部分通过双立柱代替单立柱的形式促使锯架受力平衡,基于Profibus总线设计了PLC数控逻辑实现系统精准控制锯切。采取圆形截面的碳钢锯料进行锯切实验,系统的锯切速度随时间变化曲线波动较小,验证了系统的稳定性。与传统系统相比,提高了锯切精度与锯切效率。     

干切混凝土时金刚石锯片振动及噪声的研究

干切混凝土时,金刚石锯片在实际工作过程中产生的振动和噪声是非常严重的。文章从理论上分析了混凝土锯切过程中的强振动、高噪音的原因。通过改变锯切速度、进给速度、切深以及通过采用两种不同的基体结构的锯片,研究了不同的切削参数以及锯片的结构对锯片振动和噪声的影响。在不同的锯切工艺参数和锯片结构下,测量了噪声值、噪声功率、噪声电压、振动功率和振动幅值,并对其进行频谱分析。可以从锯片的基体结构、金刚石节块的结构、锯切工艺以及锯机的整体性能等方面来进行改进,从而达到降低噪声与振动的目的。本文在理论分析和实验的基础上提出了一些降低噪声和振动的方法。     

木工带锯机适应性控制加工的最优化研究(一)——关于锯剖中带锯条位移的预测方法

为了预测木工带锯加工切削面的弯曲和粗糙度,探讨其控制方法。我们采用钨铬钴合金锯齿的木工带锯条,在无锯卡状态下,研究与锯剖弯曲有关的锯条位移、切削力、进给力、声发射计数(AE)与吃刀量、锯切速度、张紧应力、木材材质的关系,以分析探讨带锯条位移的预测方法。     

简论带锯机双向进给控制系统

台式锯、卧式锯和双边圆锯的进给控制系统不同于一般机床的进给控制,也不同于普通跑车带锯机的“摇尺控制”,而这类机床的进给控制在工艺上要求“双向控制”,即一般俗称的“开档控制”。具体以(图一)台式锯的进给拖板(俗称锯比子)与进     

基于ADAMS裁板锯分段式进给机构的设计与仿真

数控裁板锯是将人造板板材锯切为适用于复合木门的板条加工设备。为了提高数控裁板锯的裁板效率,并保证裁板的质量和加工后的平面度,现对数控裁板锯的板坯进给系统进行结构设计。通过对数控裁板锯的工作过程进行分析,确定裁板锯板坯进给系统的结构布局,并采用Solid Works仿真软件对裁板锯分段式进给机构建立模型。通过分析滑块的运动和碰撞情况,得到了碰撞接触力的公式。依据分段式送料进给机构的参数,用ADAMS软件进行了简化建模,并进行了碰撞仿真,得到实际碰撞力为1203 N。同时为裁板锯分段式进给机构的整体设计提供了理论依据。     

Application of a novel technique for band sawing using a tip-inserted saw regarding surface profiles

One way of achieving a successful forest management leading to biodiversity conservation is to ensure that wood is processed in an efficient manner. The authors succeeded in developing a new technology for bandsawing using a tip-inserted saw. The material used for the tipped edge was High Speed Steel (HSS) of designation SHK 51 according to the Japan Industrial Standard (JIS). The efficiency of the tip-inserted saw was investigated considering its effectiveness in controlling tooth marks and washboarding patterns that sometimes occur during bandsawing. The surface profile of the workpiece generated after sawing with 700 mm and 1100 mm diameter bandmills of the laboratory and industrial type respectively were determined using a CCD laser displacement sensor of scanning length 250 mm and scanning speed of 3 mm/sec at a sampling rate of 50 Hz. Under a setup wheel rotation speed of 200 rpm and feed speed of 1 m/min, washboardings were induced during sawing with the tip-inserted saw of uniform pitch. Thereafter, a tip-inserted saw of random pitch was constructed without removing the saw from the pulley and cutting tests were performed under the same cutting conditions when washboardings were induced during sawing with the uniform pitch tipped-inserted saw. It was observed that the washboarding pattern disappeared completely. Thus the tip-inserted saw of random pitch was very effective in controlling the washboarding pattern. Comparisons of the surface profiles of the workpiece generated by sawing with uniform pitch tip-inserted and stellite-tipped saws under both laboratory and industrial conditions indicate that regardless of the type of bandmill used, the surface profile measured with the laser displacement sensor was smoother for tip-inserted saws than stellite-tipped saws.     

电镀液对生产厚镀层切割钢丝半成品的影响

钢帘线企业生产切割钢丝或提供电镀黄铜半成品钢丝时,遇到黄铜镀层厚度加厚的问题。分析影响镀层厚度的各个因素:电镀镀层面质量主要取决于电流密度、钢丝浸液长度和运行速度(沉积时间)。选用赫尔槽实验,改变镀液配方,镀铜溶液主要成分P2O74-质量浓度控制在210～230 g/L,Cu2+质量浓度控制在33～36 g/L,其比值控制在6.0～6.8,可确保电镀时最大允许电流密度为18.2 A/dm2,铜层厚度提高10%～25%,满足切割钢丝成品镀层要求,改变了常用的增加镀铜槽长度或降低走线速度的方法,节省投资,提高效率。     

46—THE FORM TAKEN BY THREADS LAID ON A MOVING BELT. PART I: EXPERIMENTAL STUDY

An apparatus made to study the form taken by threads laid on a moving belt under different conditions is described. This mechanism of laying down the thread is a partial imitation of the mechanism of laying down the filaments emerging from the spinnerets during the manufacturing process of spun-bonded non-woven fabrics.

It is shown that the form of the laid-down thread can vary according to the type of thread, the height of the feed point, and the ratio of the feed speed to the belt speed. It is also shown that there is a critical value of the speed ratio at which the form changes its geometry considerably. The conditions for a homogeneous and controlled form of the laid thread are deduced.     

梳棉梳理工艺研究

探讨牵伸工艺与梳理工艺。论述了牵伸工艺与梳理工艺的关系。介绍了梳理技术的组成,针对梳理元件的重要性进行了详细分析。通过对比不同梳棉工艺,分析了刺辊与给棉板隔距、给棉板梳理工艺长度、锡林刺辊线速比、锡林与活动盖板隔距对产品质量的影响。认为:梳棉工艺的核心是正确处理梳理度、梳理强度与转移的关系,梳理元件的锋利度、粗糙度、耐用度等是工艺的基础,应遵循梳理转移适度,结杂短绒兼顾的工艺原则,优选工艺,从而提高棉纱的综合质量。     

薄膜干燥器内丙酸钙的干燥性能分析

建立薄膜干燥器的工艺计算数学模型,以25%丙酸钙为研究对象,采用数值模拟软件MATLAB对模型进行数值求解,得到薄膜干燥器的干燥段长度和干燥率,探讨进料温度、转子转速、进料量和加热温度对干燥率和干燥段长度的影响。结果表明,进料量和加热温度对干燥率和干燥段长度影响较大,而进料温度和转速影响较小,该结果可为丙酸钙的干燥提供依据。     

基于MATLAB空间四连杆引纬机构运动仿真

为了分析探讨剑杆织机空间四连杆引纬机构参数变化对其运动学特性的影响,通过代数解析的方法建立了该机构各部分数学模型,编制了MATLAB程序对其进行运动仿真,得出了运动特性曲线,同时定量分析了转速和曲柄长度变化对引纬机构运动规律的影响。分析结果表明,所得的运动特性曲线符合所需引纬要求,可以通过调节转速和曲柄长度优化运动规律曲线。     

Surface roughness evaluation in medium density fibreboard rip sawing

Wood/panel specific gravity is a factor that has to be evaluated in the machining process because it affects the cutting forces behavior, plays an important role in the tool wear mechanisms and it is closely related to the surface roughness of the manufactured product. In the case of medium density fibreboard (MDF), which compared to solid wood is a homogeneous wood product, it is recognized that the specific gravity varies regularly across its profile, and these variations generate an uneven surface quality at the edge of the panel when machined. Among the operational parameters affecting the quality of the new surface, the cutting process kinematics is one of the most important parameters, namely the cutting speed and the chip thickness. In MDF industrial rip sawing operations, climb cutting and conventional cutting are additional parameters that affect the cutting quality. The objective of this study was to assess the surface roughness across the MDF panel profile produced by the rip sawing operation and to study the effect of cutting speed, mean chip thickness and cutting direction. The findings lead to the conclusion that low levels of surface roughness are reached when the cutting speed is increased at even higher feed speeds, particularly at the edge of the board. High correlation coefficients were found between mean chip thickness and surface roughness for both cutting directions. Finally, the specific gravity variation within the profile of the panel explains very well the resulting surface roughness found.     

棉精梳机钳板机构开闭口分度分析及仿真研究

为了提高精梳机精梳质量、简化精梳机钳板开口机构,利用运动学矢量方法进行分析,以立达E62型精梳机为例,建立钳板开口机构开闭口时间及开闭合分度与机构参数关系的数学模型;通过三维虚拟样机模型导入ADAMS进行仿真,得到开口时间和设想杆长度的变化关系,分析该机在400 Nip/min时的钳板开口机构开口时间和设想杆长度之间的仿真关系曲线,对比MATLAB计算结果与ADAMS仿真结果。指出:在假想杆长度为103 mm时,钳板开口机构的开口定时分度为6.587 9、闭口定时分度为32.436;在开闭口瞬时时刻随设想杆长度增加,开口定时分度会变早,闭口定时分度会延后;钳板机构开闭口数学模型可以研究其他参数对开闭口分度的影响。     

Structural Properties of Corn-Legume Based Extrudates as a Function of Processing Conditions and Raw Material Characteristics

The effect of extrusion conditions, including feed rate (2.52–6.84 kg/h), feed moisture content (13–19% wet basis), screw speed (150–250 rpm), and extrusion temperature (150–230°C) on structural properties of corn-legume based extrudates was studied. Four different types of legumes, chickpea, mexican bean, white bean, and lentil were used to form mixtures with corn flour in a ratio ranging from 10 to 90% (corn/legume). A simple power model was used to correlate porosity with extrusion conditions and material characteristics. The influence of feed rate in the extrudates porosity is incorporated into mean residence time. Porosity of extrudates was found to increase with temperature and residence time and to decrease with feed moisture content and corn to legume ratio. Screw speed did not affect extrudates properties. Expansion ratio showed a similar behavior with porosity. The addition of legumes (protein source) led to more dense products. Comparatively, the usage of white bean in mixtures for the production of snacks, led to a product with higher porosity than those with other legumes.     

Angewandte Problemlösungen beim Kreissägen in den USA

Reduction of kerf and sawing variation is one of the major concerns today in the sawmilling industry in the United States. Significant advances have been made during the last two decades towards the use of thin kerf (≦2.5 mm) accurate sawing through innovations in the design of the sawing machine, specifications of the saw blade and the sawing process, on-line saw vibration control and improved saw maintenance. The most significant accomplishments, for instance the application of critical speed theory, are discussed.