Manufacturing Technology Of Original Re-combined Arc Bamboo Material

China has abundant bamboo resources, which can be used in developing original re-combined arc bamboo board material,replacing bamboo with wood may have important significance in biomass materials,especially non-wood materials field.The scientific and technological support of "Eleventh Five-Year" plan—"the key research and development in technology and equipment of efficient use of bamboo replacing wood" (2006BAD11A16) funding this paper.For carrying out innovative research and processing bamboo into arc segments,through pro-treatment, drying, finger joint, glue, group billets, hot pressing (including flatpressure, lateral pressure), polishing and other processes, original re-combined arc bamboo material is developed, also some special equipment,such as Splitting and removing inner segment machine, high-frequency hot press (including the level pressure and lateral pressure)and so on. This paper study on original re-combined arc bamboo material and related technology,conclusions are as follow:(1)According to mechanical analysis of mathematical model of original state re-combined bamboo materials,compare to the rectangular bamboo unit which radius of curvature tends to infinity ,the arc bamboo unit with smaller radius of curvature have high strength endurance, in the case of subject to the same load, they relatively less prone to deformation or fracture.When the load uniformly distributed, their radius of curvature is constant, arc-shaped bamboo unit compare to the non-circular shape (including the rectangular bamboo unit) can withstand greater loads.Original re-combined arc bamboo board material fully utilize the inherent properties of bamboo fiber (hollow structure, inner segment), so that its pole bending, compression and shear capacity enhanced, not only retains the original mechanical properties of bamboo, but also ensures the high utilization of bamboo, high strength, large size, density distribution, maintaining the natural texture of bamboo.(2)Maintaining the original state of bamboo and subsequent high-frequency high-frequency hot press in pro-manufacturing process is particularly important to arc bamboo drying. During drying characteristics the experiments, the higher the drying temperature,the faster drying,in the same time period, high drying temperature has low moisture content, and high temperature compare to low temperature drying, the shrinkage rate is high, deformation is great. With the decline in water content of arc-shaped bamboo, shrinkage rate enhanced, radius increased, when the water content below 5%, the shrinkage rate and the radius stabilized. Arc bamboo in the drying process, shrinkage occurs in addition to deformation, it will also produce shrinkage, cracking and other defects.Different drying temperatures, arc bamboo defects occurred varied. When the drying temperature below 70℃, drying is better, did not produce obvious defects, when the drying temperature above 70℃, the arc bamboo will produce warping phenomenon; when the drying temperature is higher than 90℃, the arc warping deformation in the production of bamboo is also accompanied by shrinkage phenomena; when the drying temperature higher than 100℃, the arc bamboo exist warping, shrinkage and cracking phenomenon.Different parts of the arc bamboo, there are some differences in shrinkage.In the chordwise shrinkage outer of bamboo is greater than inner side shrinkage rate of about two times; the chordwise average shrinkage rate is bigger than the radial.Arc bamboo on the whole, the length and unit of bamboo have little effect on the shrinkage rate, geometry and radius,but the shrinkage rate is less than bamboo parts section part without drying shrinkage.(3)According to laboratory and pilot plant trial of arc bamboo material,the property of production which are made from PF is slightly lower than those which are made from MDI's. so it is better to use PF when taking cost of production into account. If there are double-sided PF capacity of 250g/m2, and unit thermal pressure of 2.0MPa or 3.0MPa, the material have fine properties and little difference. Taking energy conservation and reduce costs into account, the ideal conditions are 2.0MPa.Through mechanical testing, the original re-combined bamboo material with bending strength and elastic modulus reach to 60E superior product structural laminated veneer lumber, C-level structure with wood composite board and bamboo plywood type B class 50, which can be used as structural material for load-bearing situations.(4)It have developed and designed the bamboo splitting and removing inner segmentmachine for original re-combined bamboo material,fixing splitting knife,back of it removing inner segment knife boxes fixed to the inner wall.Elastic clamping fixed knife, spring force knife, and removing inner segment milling cutter are in knife boxes.Splitting and removing inner segmentwill save cost ,streamline processes and improve productivity.(5)High-frequency hot press is particularly important in production technology and equipment of original re-combined arc bamboo material,which has:vertical pressure, lateral pressure and lengthwise pressure,with duplex mode of production, automatic access to materials function; the press control system with three network control structure and equipment control machines, on-sitecontrol to complete process control, plant control may be options to complete the coordination of production and management;it also has high-frequency electromagnetic protection, the high-frequency heating package of positive plates are surounded by the shield to prevent electromagnetic leakage.Three-dimensional with adjustable and linkage pressure method,high-frequency hot press machine can avoid the occurrence of arc bamboo rolling,using high-frequency dielectric heating method to process thick bamboo sheet which thickness up to 60mm,having a lot of advantages.such as high efficiency, fast heating, overall internal and external heating, green and environment protection and so on.