大规模定制家具生产线规划与车间管理关键技术

随着信息化在我国制造行业的推广,大规模定制在我国家具制造业的广泛应用正处在成长期,目前国内大多数板式家具企业和橱柜企业都开始真正实行大规模定制,未来几年将会是大规模定制家具的高速发展时期. 大规模定制家具的关键技术一般是由多个相对独立又具有密切联系的部分组成,包括面向大规模定制家具产品的开发设计技术、面向大规模定制的制造技术及大规模定制的支撑技术等[1]. 对家具车间进行合理的生产线规划和工艺流程管理,是大规模定制生产制造技术的保障.大规模定制家具生产线规划主要是确定生产线系统的规模、构成和布局.对构成生产线系统的机床设备进行合理的选择和优化配置可以减少投资费用,降低维护费用和运行成本,提高机床利用率,对生产线系统的长期高效运作具有十分重要的意义.合理的规划和管理才能使大批量生产与定制生产这两种互相对立的生产模式融合在一起,将二者的优势有机地结合起来,为家具产业适应新的需求,调整生产模式,提出新的技术解决方案.才能真正使个性化家具产品生产周期缩短,提高原料利用率,降低能耗,产品成本降低等.     

工业4.0时代中国家居产业的新思维与新模式

家居产业作为劳动力密集型传统产业和生活关联型的民生产业,"个性化定制,柔性化生产"已成为产业未来发展的强大引擎。从"工业4.0"与"中国制造2025"、定制与大规模定制、家具与家居的定制模式等方面,阐述家居产业应该立足于坚实的工业基础,积极探索"制造业+互联网",实现产业转型升级和创新发展。     

大规模定制家具柔性制造系统构建与关键技术

通过分析柔性制造系统(FMS)的基本原理和运行特点,结合大规模定制家具生产中的问题,阐述搭建大规模定制家具FMS系统平台的必要性和可行性,提出构建大规模定制家具FMS系统的三大关键技术:标准化产品设计与工艺规范、模块化柔性生产、信息化动态管控,并对关键过程进行解读,为我国大规模定制家具企业实施柔性制造提供参考。     

大规模定制家具快速响应机制及关键技术的研究

从家具市场发展的影响和生产模式的限制两方面阐述了实现大规模定制家具客户需求快速响应的必要性,通过对大规模定制家具快速响应内涵的分析,构建了大规模定制家具快速响应的关键技术架构,包括客户需求信息的采集与处理技术、产品开发设计与快速配置技术、生产线优化与柔性制造技术、供应链协作与运转技术及企业信息共享与管控技术,并对家具快速响应机制的基本流程和实施过程进行了详细解读,为我国大规模定制家具企业实施客户关系管理时实现客户需求快速响应具有一定的借鉴作用。     

家具大规模定制的发展背景及现状研究

大规模定制是试图将大批量生产的速度和成本与满足客户定制的个性化需求结合起来的一种新型生产模式.本文通过对家具大规模定制发展的技术背景和发展现状的分析,为我国家具大规模定制的实施和发展提供有效的理论依据和实践参考,为行业的持续发展和产业升级提供有力支撑.论文从设计技术、制造技术和管理技术3个方面分析家具大规模定制发展的技术背景,论述家具大规模定制生产模式的主要特征,在此基础上阐述家具大规模定制的国内外发展研究现状,最后总结我国实施家具大规模定制存在行业标准化、模块化程度低,数字化、自动化水平低和企业管理信息化不足等问题并针对以上具体存在的问题给出了相应的对策.     

家装业定制家具设计与制造流程中的问题探析

针对家装企业的定制家具中存在的"设计与生产效率低、材料浪费大、出错率高"等诸多问题,提出通过定制家具系列产品数据库及按需定制的家具高效设计系统的研发来提高设计效率;通过采用计算机条形码技术和"拆单、拼单"生产的制造模式提高生产效率,减少出错率;可以采用大规模定制和开料软件提高原材料利用率;还可以通过不同生产环节的操作规程的制定,提高生产效率并减少出错率。     

基于柔性制造系统的大规模定制家具公理化设计研究

针对大规模定制家具生产模式,为满足生产过程的快速性、可调控性、柔性等需求,构建家具柔性制造系统(FMS)平台,结合公理化设计对FMS平台进行功能设计,提出构建大规模定制家具FMS的设计框架,以期为大规模定制家具企业构建FMS提供一种新设计方法。     

面向智能制造的家具企业数字化设计与制造

随着传统制造业智能制造帷幕的开启,向数字化转型升级已经成为企业的共识,也是未来传统制造企业的战略核心。笔者结合家具企业发展现状的分析,通过对定制家具新模式、家具数字化转型的特征和家具企业数字化的优势等进行解读,明确了家具企业实现智能制造、数字化转型是必由的趋势;通过家具信息模型的搭建、数据的转换和应用过程、家具制造过程的数据集成等方面的分析,得出面向智能制造的家具企业实现数字化设计与制造的基本要求。结合大规模定制家具的信息化建设情况,构建了面向智能制造的家具企业数字化设计与制造关键技术,并对各技术进行了详细解读,主要包括:由基础技术、单元技术和集成技术等构成的网络基础建设技术,以及由设计数字化、生产过程数字化、制造装备数字化、管理数字化等构成的家具数字化转型核心技术。     

大规模定制家具加工中心多钻头并行作业的优化

大规模定制家具超高的生产效率与高度个性化的产品两大特征决定了其需要依赖高水平的信息化与自动化组织生产,是家具制造业智能制造的前沿领域。运用数控加工中心开展钻孔作业是调和个性化产品制造过程中的矛盾、实现柔性生产的重要手段。当前,数控钻孔工序因其作业时间长且板件之间差异较大而往往成为制造过程中的瓶颈。为切实提高生产效率,本研究立足生产实际,从钻头与孔的位置关系中寻求突破口,提出了数控加工中心多钻头并行作业优化问题。以优化钻头排列为主要途径,减少下钻次数为核心目标,基于制造大数据与工艺规则挖掘信息并简化建模,采用差分进化算法求解钻头排列方案,进一步通过聚类算法探索出面向未来高自动化水平下的差异化钻头排列,形成了一套具有实际意义与普适性的优化方法。通过理论与实践验证了该方法的有效性,达到了缩减作业时间、提升加工效率的目的。对打通大规模定制家具制造瓶颈、推动定制家具智能制造具有一定的指导意义。     

家具“大规模定制”的应用突破

"大规模定制"(Mass Customization)是指能够以大规模生产的成本和速度,为单个客户或多品种小批量市场定制生产任意数量产品的一种制造新模式.美国<财富>杂志曾经预言,"大规模定制"模式将改变21世纪的制造业,正如大规模生产模式改变了20世纪的制造业一样,"大规模定制"生产,兼有大规模生产和定制生产的特点,因此,它能够以生产批量大、上市快、成本低的优势,恰逢其时地去满足当前社会消费愈来愈多样化、个性化的需求.     

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.     

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.     

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.     

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.     

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。     

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.