曲线地板纵向开榫机主轴机构设计与研究

通过对曲线地板纵向开榫加工工艺的分析,提出了一种可以曲线进给的曲线地板纵向开榫加工的主轴机构。根据对加工工艺的分析结果对曲线地板纵向开榫机、主轴机构、纵向导轨支架总成进行总体布局和结构设计。为确保设计的可靠性对主轴机构的单元切削力、切削功率等主要参数进行设计计算,也对纵向导轨支架总成的重要部件长导轨架进行有限元分析,得出相应的结论,以此来验证该设计是否符合实际需求。提出的主轴结构可以解决曲线地板开榫加工时的重复定位的问题,加工工艺也得到了很大的改善,同时曲线地板开榫加工的效率和精度有很大的提高,该项研究为曲线地板纵向开榫加工提供了一种新型机构。     

门窗材双端刨铣自动换刀加工中心的结构设计

由于国内门窗窗型加工设备大多处于半自动化状态,更多依赖于国外进口设备,且存在着加工效率不高、精度低等缺陷,因此提出了门窗材双端刨铣自动换刀加工中心的设计。通过对门窗材双端端头铣型加工工艺分析,完成门窗材双端刨铣自动换刀加工中心结构总体布局,利用Solidworks软件对加工中心端头铣削结构进行实体建模,确定了加工中心端头铣削结构主机总体结构,并对齐头锯、端头粗铣铣削主轴的切削力和切削功率进行设计计算,得到主锯电机功率7.5 k W、铣削主轴铣削电机功率为7.5 k W,符合加工功率要求,并完成齐头锯组件、粗铣主轴组件、精铣主轴组件、榫头铣座送料结构、刀具位置调整机构、主机机架等结构的设计以及外购件的选型,最后运用ANSYS对粗铣铣削主轴进行静力学分析,得到主轴的应力、应变和变形云图,其最大应力值为10.305 MPa、最大应变值为0.051 527 mm/m、最大变形量为0.010 946 mm,且最大强度、刚度以及变形均在安全范围内,验证了铣削主轴满足设计要求。设计的自动换刀加工中心结构简单,能一次完成门窗材两边齐头、端头铣型工序,自动化程度高,效率高。     

木材的数控加工与数控机床（四）

９数控加工中心加工中心是一类功能较全面的数控加工机床。它把木材加工工艺中的锯、铣、钻削和开槽、铣榫等加工功能集中在一台机床上，使其具有多种加工手段。与数控铣钻床不同的是，加工中心设置有刀具库，刀具库中存放着不同数量的各种刀具和检测工具。在加工过程中由...     

普及型欧式木窗专用双槽铣主轴轴承寿命分析

从普及型欧式木窗专用加工设备双槽铣床主轴结构入手,分析了双槽铣主轴结构存在的问题,并进行了结构改进,探讨了影响双槽铣主轴轴承寿命的主要原因。     

强化地板数控横向开榫机主机结构的设计研究

针对地板生产设备大多数处于半自动化状态,且存在着加工精度和加工效率不高等缺陷,提出了强化地板数控横向开榫机主机结构的设计。通过对横向开榫机加工工艺分析,利用三维软件solirlworks对强化地板数控横向开榫机主机结构进行实体建模,确定了强化地板数控横向开榫机主机总体结构,并对齐边锯、粗铣的切削力和切削功率进行设计计算,完成了强化地板数控横向开榫机粗铣主轴件、齐边锯组件、精铣主轴件、抛光主轴组件、主机机架等结构的设计研究。设计的强化地板数控横向开榫机主轴结构简单,具有强度高、加工效率高、稳定性较好、制造成本低的优点。     

专利信息

木材金属两用钻铣机床 该机床不但可以对木材进行钻孔和打榫槽，而且也可对金属进行钻孔和铣削加工．为克服现有木工棒槽机床不能加工金属材料，且调整皮带松紧困难的缺点．本机床做了改进。其主要结构包括机架、花键传动装置、塔形皮带轮传动装置、调节板等．调节板上装有寻向轴和用于固定电机底脚的固定孔；机架上装有导向套，导向轴套在其导向孔内，导向套上还装有锁定导向轴的锁定装置。 （授权专利公告号：２４１３８７８） 人造木材 该木材是一种用于建筑上的人造木材。其采用农作物秸秆、稻壳、杂草、经粉碎的草本纤维、制盐废液、氧…     

木结构房屋加工中心CAM系统设计实现

介绍了木结构房屋加工中心结构，开发设计了木结构房屋加工中心CAM系统。该系统能够对木屋构件进行加工过程仿真，控制代码转换，可大幅度提高木屋构件加工的准确性和生产效率。     

实木地板榫槽铣削力的试验分析

【目的】以实验为基础,研究实木地板榫槽铣削加工中切削参数对切削力的影响,为不同切削工艺下加工参数的优化以及设置提供参考依据,达到提高加工质量、延长刀具寿命并用以指导生产的目的。【方法】以山毛榉材地板为试验材料,运用木材切削机理对切削速度、进给速度及切削宽度3个参数进行单因素试验,并采集切削过程中随着切削参数变化产生的切削力值,揭示在顺铣和逆铣方式下不同切削参数对实木地板榫槽铣削力的影响规律。【结果】在不同铣削方式下,随着切削速度的增大,XYZ方向的切削力总体呈降低趋势;随着进给速度和切削宽度的增大呈现升高的趋势,顺铣加工时XYZ 3个方向的铣削力变化相比逆铣加工的波动趋势小,稳定性要好。通过对铣削力回归模型进行方差分析,可知R2(Fdown)=0.9490,R2(Fup)=0.8516,均接近1,回归效果显著,验证了铣削力模型的合理性。【结论】通过对比相同切削参数在不同工艺条件下产生的切削力变化,可知顺铣加工稳定性高于逆铣加工。     

可调铣刀倾角的铣槽机构

可调铣刀倾角的铣槽机构（５００４０）黑龙江省林产工业研究所戴吉昌近年来，前西德研制出一种新型全自动开榫地板块生产设备，它可以加工长３００～１２００ｍｍ、宽５０～１００ｍｍ、１２～２０ｍｍ的各种规格的地板块。当需要改变地板块的加工尺寸时，尤其在铣槽的宽...     

民间玩具孔明锁的榫槽工艺研究

本课题以研究和发展民间玩具孔明锁的榫槽工艺为主。榫槽工艺蕴含了数学的原理,见证了中国古代的悠远文明,也为现代人传递了知识与乐趣。同时也是人民朴素审美观的结晶,蕴含着人们的心理素质和精神素质,对民俗文化的传承和思想教育起着非常重要的作用。本文运用模数分析了榫槽工艺的结构;对榫槽工艺的形式进行了形、色、质、体量的分析;也对结构与形式的关系进行了分析,通过分析不仅加深了对榫槽工艺的理解与认识,同时也为榫槽工艺的发展做出了新的探索。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Decomposition and nutrient loss from prunings of different contour hedgerow species in tea plantations in the sloping highlands of Sri Lanka

Contour hedgerows of multipurpose tree species in the sloping tea lands of Sri Lanka are expected to reduce soil erosion and also add significant amounts of plant nutrients to the soil via periodic prunings. The objective of this experiment was to characterize the biomass decomposition pattern and quantify the amount of nutrients added through prunings of six tree species (Calliandra calothyrsus, Senna spectabilis, Euphatorium innulifolium, Flemingia congesta, Gliricidia sepium and Tithonia diversifolia) currently being used in hedgerows associated with tea. Withered leaf and stem prunings (50 g) were enclosed in 2-mm litter bags, placed at 5-cm depth and retrieved after one, three, six, nine and 12 weeks. Loss of initial dry weight, N, P and K was measured. Single exponential decay function adequately described both dry weight and nutrient loss. Tree species differed significantly in their rate of breakdown with decomposition constants (k) varying from 0.0299 to 0.2006 week⁻¹ for leaves and from 0.0225 to 0.0633 week⁻¹ for stems. Gliricidia showed the highest k for leaves with the rest in the following descending order: Senna > Tithonia ≥ Euphatorium > Calliandra > Flemingia. A similar pattern was observed for loss of all nutrients with Calliandra and Flemingia always having lower k values than the rest. Although N immobilization was not observed, immobilization of P and K was observed during the first week of incubation in some species, particularly in stem prunings. Annual biomass of prunings differed significantly between tree species in the following descending order: Calliandra > Senna > Flemingia > Tithonia > Gliricidia > Euphatorium. Calliandra added the greatest amount of nutrients annually to the soil with Euphatorium adding the least. Calliandra prunings provided the annual total K requirement and 49% of the N requirement of mature tea. However, none of the species provided more than 5% of the P requirement. It is concluded that among the tree species tested, Calliandra and Flemingia are the most suitable for contour hedgerows in tea plantations of this agroclimatic region because of their higher soil nutrient enrichment capacity and slower decomposition rates which would minimize leaching losses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Effects of Seed Weight and Seed Type on Early Seedling Growth of Pinus sylvestris under Harsh and Optimal Conditions

The effects of seed weight and seed type on seedling growth of Pinus sylvestris (L.) were studied by seeding individually weighed orchard and stand seed in different mixtures under harsh (direct seeding in field) and optimal (seeding in nursery) conditions. In the nursery experiment an increase in the seed weight from 3 to 7 mg increased the seedling height by 10-27% and total weight by 27-113%, and decreased the height/diameter ratio by 5-6% after 2 yrs. With elimination of seed weight effects, orchard seedlings were 2% taller than stand seedlings in year 2. Without elimination of seed weight effects, orchard seedlings were 7-13% taller. In the field experiment an increase in the seed weight from 3 to 7 mg increased seedling height by 18-65%, stem volume by 81-274% and the number of top-buds by 23-34% in year 5. After elimination of seed weight effects, orchard seedlings were 7-13% taller than stand seedlings and without elimination of seed weight effects 20-21% taller after 5 yrs. Even after elimination of both seed weight and genetic effects orchard seedlings were 3-9% larger than stand seedlings in the field experiment. In conclusion, the influence of seed weight and seed type on growth traits and slenderness is highly significant and the influence seems to be greater in harsh conditions.     

Potential to harness superior nutritional qualities of exotic baobabs if local adaptation can be conferred through grafting

Baobab leaves form an important part of the local diet in Sahel countries and elsewhere in Africa. Existing leaf nutritional data and agroforestry performance information are based solely on Adansonia digitata L., the baobab of continental Africa. The introduction potential of Adansonia species from the center of diversity in Madagascar and from Australia remains untapped. To assess this potential, the mineral contents and B₁ and B₂ vitamin levels of dried baobab leaves were determined for five-year old trees of A. digitata, A. gibbosa (A. Cunn.) Guymer ex D. Baum, A. rubrostipa Jum. & H. Perrier (syn. A. fony Baill.), A. perrieri Capuron and A. za Baill. grown in an introduction trial in Mali. Nutritional data were evaluated against survival and vigor to identify promising germplasm. Leaf vitamin and crude protein contents were highest in the Madagascar species, especially A. rubrostipa (B₁ 88 mg 100 g⁻¹, B₂ 187 mg 100 g⁻¹, protein 20.7% dry weight). However, the local species far outperformed the introductions in survival, tree height, basal diameter and resistance to termites. We suggest grafting as a way of harnessing the vigor of well-adapted local baobab varieties to the superior nutritional profiles of A. rubrostipa and others. Cross-species grafting tests in Adansonia were successful, thus creating new agroforestry possibilities with different scion/rootstock combinations.     

Modelling of adequate pretwist for obtaining straight timber

Abstract

Wood in general and wooden studs in particular are often distorted owing to uneven shrinkage during the drying process in the sawmill. Twist is often the most detrimental of all types of distortion, and it is caused by spiral grain in combination with variations in moisture content. For sawmills, the objective is to produce dried, straight boards, and one method of dealing with boards with excessive spiral grain is to sort them out and then dry them in a pretwisted position to obtain straight boards after drying. A model using the finite element (FE) method for the simulation of drying twist distortions was first calibrated against laboratory experiments in which boards were dried with and without restraints and pretwists. After the calibration, the FE results were compared with industrial test results for boards that were dried without restraints or with restraints with zero pretwist, i.e. straight restraints. The FE model used an elastic–ideally plastic material model to obtain permanent deformations. The calibration was to set the yield stresses so that there was a good match between FE results and results from the laboratory experiments. The comparison between the industrial test results and the FE results showed that the FE model is capable of realistic simulations of drying boards with and without restraints and presumably also pretwists.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Growth of Phlebiopsis gigantea in wood of seven conifer species

Heterobasidion parviporum and Heterobasidion annosum are widely distributed root‐rot fungi that infect conifers throughout Europe. Infection of conifer stumps by spores of these pathogens can be controlled by treating fresh stumps with a competing non‐pathogenic fungus, Phlebiopsis gigantea. In this study, growth of three Latvian strains of P. gigantea and the biological control agent ‘Rotstop’ strain was evaluated in stem pieces of Norway spruce, Scots pine, lodgepole pine, Douglas‐fir, Weymouth pine, Siberian larch and Sitka spruce. The growth rates of one H. parviporum and one H. annosum isolate were also measured in the same stem pieces. The growth rate of P. gigantea varied greatly in wood of different conifer species. It was higher in the three pine species, lower in Norway spruce and lowest in Sitka spruce and Siberian larch, and in Douglas‐fir, this fungus did not grow. The largest area of wood occupied by P. gigantea was in lodgepole pine. Growth of Latvian isolates of P. gigantea in the wood of Pinus and Picea species was comparable to that of the Rotstop isolate. Consequently, stump treatment with local P. gigantea isolates should be recommended. However, our results suggest that Douglas‐fir stump treatment against Heterobasidion by P. gigantea may be ineffective and other stump treatment methods should be considered.