THE OPTIMUM CUTTING SPEED OF CIRCULAR SAW

Whenthepwticlebortswerecutbyuseoftllllgstencarbidetippedcircularsaw(Fig.l),th9whcientcuttingspeedfortheminimumcostandmaximumproductionwasdiscussedforafewyears.Ingeneral,thehigherthecuttingspeed,thehigherthecuttingheatproducedandtheshorterthelifeofthetoolresulted.Althoughthehighercuttingspeedcouldmalletheproductivityhigher,theamountofwearoftoothwasincreasedandthenthetimesofchangingsawswereincreased.There-foretherewasanoptimumrangeofcuttingspeedswhentheparticleboardswerecutbycircularsawbasedonan…     

Performance of coated carbide tools in turning wood-based materials: Effect of cutting speeds and coating materials on the wear characteristics of coated carbide tools in turning wood-chip cement board

This paper reports on the performance of coated carbide tools in turning wood-chip cement board. The coating materials studied were titanium carbonitride (TiCN), titanium nitride (TiN), chromium nitride (CrN), and titanium nitride/aluminum nitride (TiN/AlN), which were synthesized on the P30 carbide substrate. The aim is to investigate the effect of coating materials and cutting speeds on the wear characteristics of the coated carbide tools. Cutting tests were performed when turning wood-chip cement board at cutting speeds of 30, 40, 50 and 60 m/s, a depth of cut of 1mm, and a feed of 0.05 mm/rev. The results of the study show that the coated carbide tools provided better performance than the P30 carbide tool, especially in terms of reducing the progression of the wear rate and clearance wear. The TiN/AlN-coated carbide tool showed the smallest increase in both wear rate and clearance wear with an increase in cutting speed and had the longest tool life among the coated carbide tools investigated. Though the TiCN-coated carbide tool was observed to have a low wear rate and low clearance wear for cutting speeds of 30 and 40m/s, when the cutting speeds were >50m/s its wear rate and clearance wear were almost the same as those of CrN-and TiN-coated carbide tools, which had high values for these parameters.Part of this paper was presented at the 21st IUFRO World Congress, August 2000, Kuala Lumpur, Malaysia     

基质和激素对无刺枸骨扦插成活率及其生长影响研究初报

无刺枸骨在5种不同基质中,以及在经用NAA,IAA和IBA等3种激素处理的山黄土中扦插后,对其下端伤口愈合率、生根率、成苗率以及苗高、地径、新梢长、根数量、最大根长、最小根长、根系幅度和鲜重等11个指标进行了研究。结果表明:在3号基质(山黄土与珍珠岩容积比为1∶1)中插穗下端伤口愈合率、生根率、成苗率分别为90.67%,85.33%和71.33%,高于其他基质中的插穗,且3号基质中苗高、新梢长、最大根长、最小根长和鲜重等5个指标的平均值也都优于其他几种基质,与对照(砻糠灰)相比,增幅分别为0.18%,55.56%,22.80%,30.00%和13.66%;100 mg/L NAA浸泡2 h或1 000 mg/L IBA速蘸5 s,能显著提高插穗的下端伤口愈合率、生根率和成苗率。其中,经100 mg/L NAA处理过后的插穗,其苗高、新梢长、根系数量、鲜重等指标较对照(清水)增幅分别为18.79%,128.57%,43.90%和14.39%,生长优势最强。     

Effects of commercial thinning,log position in the stem,and cutting width on the surface quality of cants produced by a chipper-canter

Fifteen stems of jack pine (Pinus banksiana Lamb.) of 3 commercial thinned plots (control, moderate, and intensive thinning) and 15 stems of black spruce (Picea mariana (Mill.) B.S.P), both coming from the Abitibi-Témiscamingue region – Canada, were cross-cut into three 2.4?m length sections: bottom, middle, and top logs. Logs were processed with a chipper-canter at three cutting widths (12.7, 19.1, and 25.4?mm), producing chips and a three-faced cant. The middle section of the cant was used to evaluate surface quality across the grain on each face. Roughness and waviness parameters and depth of torn grain were recorded. Knot characteristics were assessed in the three cant faces. Poorer surface quality was found in the lower part compared to the upper part of the cant for both species. At larger cutting widths, jack pine logs coming from a natural stand showed lower surface quality compared to logs from thinned stands. Black spruce waviness increased with the cutting width and stem height. These results were attributed to the increase of forces and vibration when cutting at larger cutting widths, which was worsened by the presence of bigger, more numerous knots at the control plot and in the top logs. Black spruce had deeper torn grain compared to jack pine. Their differences in knot characteristics resulted in a maximum torn grain depth favored by the presence of more knots rather than by bigger knot size. Other knot characteristics, such as the position of the knots in the cant face, the insertion angle of the branch and the distribution of the knots around the log, should be studied to better understand the relationship between torn grain formation and knottiness.     

外生菌根菌和植物生长物质复合制剂对杨树扦插苗生长及抗逆性的效应

通过扦插试验研究了由植物生长物质和树木菌根菌组成的复合制剂对108杨扦插苗成活率、苗高、地径、根茎比、菌根侵染率、毛根数、生物量、树体电容、叶绿素含量以及抗病性相关酶活性等指标的影响。发现复合制剂可以促进苗木的根系生长，苗木根系的毛根数、菌根侵染率及根茎比指标较对照有显著提高；可以促进苗木地上部分的生长发育，成活率、苗高、地径、生物量、叶绿素含量、长势等指标较对照均有显著提高；可以提高苗木的抗病能力，苗木的树皮相对膨胀度、过氧化物酶活性、多酚氧化酶活性及苯丙氨酸解氨酶活性较对照均有显著提高。经IBA溶液浸泡处理亦可有效提高苗木的生长，但整体效果不及复合制剂的最佳处理。初步确定了复合制剂的最有效成分配比及处理方法。