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。     

板式定制家具智能车间数字孪生模型探讨

介绍数字孪生技术的发展及应用现状,结合板式定制家具信息化建设情况及数字孪生车间解决车间具体问题的特有能力,分析数字孪生技术在板式定制家具生产车间应用的可行性。数字孪生技术能够有效地解决制造车间运行问题,应对生产动态变化,助力板式定制家具企业数字化转型。提出板式定制家具数字孪生车间的构建技术与实施策略,探讨信息采集、模型构建及数字孪生系统搭建等关键问题,以期为定制家具行业实施数字孪生体系做出初步探索,推进企业实现全面的智能制造。     

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.     

实木家具数字化机加工车间的构建思路与布局方法

在新一轮工业革命的背景下,传统制造模式依托先进的信息和制造技术,可以实现制造过程的重构,具备更加灵活和智能的特性。简述智能制造背景下数字化车间的系统架构,结合工业互联网相关原理和实木家具机加工车间的职能,探究实木家具数字化机加工车间的架构,分析数字化车间的六大应用场景：数字化设计、数字化生产、数字化控制、数字化运输、数字化仓储、数字化安全防护。结合某公司实际案例,阐述规模化生产下的实木家具数字化机加工车间生产线布局方案。以期为实木家具企业智能制造模式提出新的技术解决方案。     

实木定制家具的设计生产瓶颈与解决途径

通过对YH家居材料有限公司的实木定制家具生产线进行调研,归纳实木家具定制化生产的现状,对比实木家具和板式家具在定制中的不同之处,总结出目前实木定制家具企业设计和生产中的瓶颈问题。希望通过引入成组技术,编码技术,搭建实木定制家具设计生产系统和实木家具标准零部件库的作用,为实木定制家具生产企业解决瓶颈问题提供一定的参考。     

基于价值流图的板式定制家具小板件生产线负荷平衡

大规模定制和多样化需求的制造模式使板式定制家具企业面临严峻的挑战,为了提升板式定制家具企业生产线效率,缩短生产交付周期,以板式定制家具企业某车间生产线为研究对象,通过价值流图研究生产线情况,识别出生产线负荷平衡率低、生产布局不合理及在制品库积压等问题,利用因果分析法分析问题成因。运用流程程序分析法、5W1H提问法和ECRS原则、双手动作分析等工业工程法对瓶颈工序进行改善;对不合理生产布局进行调整,结合改善效果,绘制了未来价值流图;针对生产线负荷不平衡的问题,建立0-1整数规划数学模型,并运用LINGO求解最小生产节拍等。结果表明,优化效果明显,瓶颈工序作业时间减少,生产线负荷平衡率由52.58%提升至86.74%,平滑性指数由10.45降至5.99,板件搬运效率提升,在制品库存得到显著改善。本研究旨在优化板式定制家具企业生产线,提升生产线负荷平衡,实现精益化生产,以期为板式定制家具企业生产线平衡优化提供新思路。     

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。     

中国智能家具产业现状与发展趋势

为探究中国智能家具的产业现状、技术发展情况和发展趋势,采用文献查阅、企业实地调研方法,对中国智能家具产业现状进行了综述分析,包括中国智能家具的发展经历和智能家具特征:中国智能家具迎来数据驱动、人工智能等多元发展的新时代;中国智能家具产业和技术发展情况:技术体系尚未完全成熟,但随着互联网行业的加入,技术上必将会进入新的高度,智能家具产品也必将更智能;中国智能家具产品和控制方式逐渐由人为到系统自动控制的方向转变;通过中国智能家具市场和产业情况,对其发展过程中的关键技术进行分析,包括:智能家具单品的嵌入式系统技术、传感器技术和智能家居互联平台的短距离无线通信技术、人工智能技术、智能交互技术等;最后对中国智能家具面临的挑战与发展机遇进行了解读。为传统家具产业向智能家具转型升级过程中如何创新和占领家具市场起到借鉴作用,为世界了解中国智能家具的发展情况提供帮助。     

木家具工艺过程数字化管理平台构建与应用北大核心

从分析构建木家具工艺过程技术规范数字化管理平台的必要性入手,提出了构建木家具工艺过程技术规范数字化管理平台系统的基本架构——实木家具零件基础信息管理系统、实木家具制造工艺规划体系系统和实木家具生产过程监控与信息处理系统,探讨了基本架构中各模块的功能和特点,并对木家具工艺过程技术规范数字化管理平台的可视化监控的基本过程与流程进行了分析,在此基础上,总结了信息同步方法与管控过程的相应技术——零部件信息的数字化管控、工艺规程的标准化管控、可视化零部件生产车间全程监控,由此实现实木家具企业工艺过程连续信息流的全集成,为木家具生产机加工车间提供一个具有快速反应、有弹性、精细化特点的制造环境。     

智能制造,推进实木定制规模化——威力中国第十五届室内展

正2017年9月,威力中国一年一度的室内展如期隆重举行,来自国内实木加工、整木定制领域的企业代表及东南亚国家考察团200余人出席盛会。针对近年来行业定制的热点,板式家具的定制生产已日趋实现规模化,倒逼作为高端产品的实木家具制造业的转型升级。作为实木加工领域的领军企业,威力公司提出了今年室内展论坛的主题:智能制造——规模化实木定制。     

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.     

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.     

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.     

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.     

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。