Machining Properties Of Twelve Plantation Woods In China

Machining properties are main characters and factors for wood processing and utilizating. In this study, plantation wood of seven valuable hardwood species (Toona sinensis, Tectona grandis, Catalpa bungei, Cinnamomum camphora, Juglans mandshurica, Schima superb and Liriodendron chinense), and five less-commercially used species (Castanea mollissima, Robinia pseudoacacia, Juglans regia, Ginkgo biloba and Cryptomeria fortunei) in China were selected for evaluation of wood machining properties. Planing, sanding, shaping, boring, mortising and turning testing were conducted according to the state forestry industrial standard LY/T2054-2012"methods for evaluating machining properties of lumber". The main outputs of this work can provide scientific data for high-efficient wood utilization of the valuable hardwood species and less-commercially used species from plantation resources.The final value of quality grade was selected for evaluation planing properties. However, for sanding, shaping, boring, mortising and turning properties, the percentage of qualified specimens was used for quality evaluation. Meanwhile, the comprehensive machining properties for each species were evaluated by total weighting value based on the results of all of six tests. The main results of this study were shown as follows:1) For wood planing, the results shown that Liriodendron chinense (final value of quality grade:4.80) was the best species of valuable hardwood species and Catalpa bungei yields a lowest value (4.10). In less-commercially used species, Castanea mollissima had the best planing performance (4.73) than other species and the lowest quality value was yielded in Juglans regia (4.20). It was indicated that the effect of cutting depth and feed speed on planning quality of each species was significant. However, there was no significant inflence on the surface roughness. The main defects of specimens were torn grain and fuzzy grain.2) For wood sanding, among valuable hardwood species, the best performance was obtained by Tectona grandis (percentage of qualified specimen,120grit:100%,80grit:92%), and Toona sinensi (120:48%,80:38%) yielded the worst quality. The excellent performance was shown in Ginkgo biloba (120:100%,80:94%) in less-commercially used species and results of Robinia pseudoacacia (120:78%,80:72%) was the lowest. Sanding properties and surface quality by using120abrasive grit was higher significantly than that by80grit. The main defects of sanding were surface fuzzy and layer lift.3) For wood shaping, except for Juglans mandshurica (percentage of qualified specimens:98%), shaping performance of all of other six species in valuable hardwood were excellent. Meanwhile, the best shaping performances was shown in all of five less-commercially used species. The main defect during the processing was raised grain.4) For wood boring, Tectona grandis (percentage of qualified specimens:94%) had the best performance. Lower quality was occurred in Catalpa bungei (68%) and Juglans mandshurica (57%) of valuable hardwood species. In less-commercially used species, Ginkgo biloba (88%) had the best performance. However, worse quality was indicated in Juglans regia (42%) and Cryptomeria fortunei (40%). The main defect of boring was fuzzy at the lower edge of boring hole, which was easily appeared in softwood.5) For wood mortising, the best mortising properties was shown in Tectona grandis (percentage of qualified specimen:100%), Schima superb (100%) and Cinnamomum camphora (100%). The quality of Toona sinensis (97%) and Juglans mandshurica (98%) was lower than other species in valuable hardwood. In less-commercially used species, the mortising properties of hardwood species was better than that of two softwood species, Ginkgo biloba (86%) and Cryptomeria fortunei (82%). Torn grain was the main defect for mortising process, which was mainly appeared at the lower edge of mortise.6) For wood turning, the excellent quality was observed in all of seven valuable hardwood species. For less-commercially used species, The better quality of Robinia pseudoacacia (percentage of qualified specimen:100%), Ginkgo biloba (100%) and Cryptomeria fortunei (100%) was shown than that of Castanea mollissima (97%) and Juglans regia (98%). The main defect appeared during the turning process was fuzzy grain. 7) For the valuable hardwood species, higher value of the comprehensive evaluation value was obtained respectively in Schima superba (total weighting value:48) and Liriodendron chinense (47) to indicate the comprehensive machining properties of these two species were excellent. For all less-commercially used species, the total weighting value of all species was above40, except for the species of Juglans regia (39). Among all of twelve different species, total weighting value of Toona sinensi (39), Juglan regia (38) and Juglans mandshurica (39) was slightly less than40.