机床液压系统正确维护与保养

机床液压系统的好坏不仅取决于系统设计的合理性和系统元件性能的的优劣,更关键的是如何正确维护与保养。本文以机床液压系统为研究对象,针对企业现场实际常见的问题提出了正确维护与保养的注意事项和关键方法。     

用于高硬度模具钢SKD11的铣刀几何角度优化及试验

在切削淬硬模具钢SKD11中,为开发和选用与生产条件相匹配的具备优化几何角度的高性能铣刀,对专用于高硬度模具钢SKD11铣刀的几何角度进行了优化及试验分析.设计了4类不同几何结构的TiAlN复合涂层铣刀.从切削力、切削振动、切削变形、铣刀耐用度以及铣刀磨损机理等方面对这4类铣刀高速铣削SKD11过程进行了研究,综合评价其铣削性能,确定了在常用的高速加工生产条件下的优化铣刀.所选择的优化槽形铣刀具的寿命比之其他刀具延长3倍,在切削力和切削振动方面,该刀具具有最稳定的表现,而且大小较其他刀具下降70%.     

HTM-63H型数控机床故障诊断和排除

通过对HTM-63H型卧式加工中心B轴无法回零工作故障、Y轴光栅尺故障和机床运行时主轴故障这三个典型故障现象的分析及处理过程描述，介绍了数控机床现场维修常采用的方法。     

数控车床工的必备知识和操作技术

论述了数控车床工必须要掌握的数控车床"特点、组成、坐标、面板、模式"五个方面的知识和操作技术。     

Performance of coated carbide tools when grooving wood-based materials: effect of work materials and coating materials on the wear resistance of coated carbide tools

This paper presents the performance of coated carbide tools when grooving various density hardboards and wood-chip cement boards. Work materials of low density (about 0.8g/cm³) and high density (about 1.2g/cm³) were tested. The coating materials studied were chromium carbide, titanium carbonitride, and titanium carbide, which were synthesized on P30 carbide substrate using a chemical vapor deposition method; titanium nitride, chromium nitride, and titanium carbonitride were synthesized using the physical vapor deposition method. Cutting tests were performed during grooving at a cutting speed of 1000m/min and a feed rate of 0.1 mm/rev. The results of the study show that the coated carbide tools are more advantageous in reducing the progression of tool wear and retaining lower normal force and noise level when cutting both hardboard and wood-chip cement board of high density than was the uncoated carbide tool. The wear rate of the coated carbide tools for the wood-chip cement board increased more rapidly than that of the hardboard with increasing densities. Though the coated carbide tools suffered more wear with the low-density wood-chip cement board than with hardboard, their normal force and noise level were always lower for the low-density wood-chip cement board.Part of this paper was presented at the 11th Annual Meeting of the Chugoku Shikoku branch of the Japan Wood Research Society, Matsue, Shimane, September 25, 1999     

新型内孔挖槽刀具的结构和工作程序

本文介绍了斜楔式和偏心式两种新型内孔挖槽刀具的结构和原理．实际使用证明，这两种刀具都具有径向自动进刀和退刀，轴向位置可调，工作性能可靠，切削效率较高，加工表面质量好等特点，适用于多种机件内孔环形槽的切削加工．     

Research on Step/Iges Conversion Tool of Surface Model AP203-Based

Most CAD systems conform to STEP standard and IGES specification as their input/output interfaces. In this paper,the STEP/IGES conversion tool of surface model based on AP203 is presented. The interface architecture of conversion tool and program language representation of STEP integrated resource construct are discussed in detail,and the mapping of surface structure and the conversion of entity data between STEP and IGES are established. Finally,an applied example is given.     

Development approach and evaluation of the Nutrient Expert software for nutrient management in cereal crops

Meeting the demand for more food in the next 20–30 years requires intensifying cereal cropping systems and increasing current yields to about 70–80% of the genetic yield potential. A dynamic and robust nutrient management approach such as site-specific nutrient management (SSNM) will be essential to increase yields and optimize profits while maintaining the productivity of these intensive cropping systems. SSNM has increased yield and profit in rice, maize, and wheat in major cropping systems in Asia; but, crop advisors have found it complex and difficult to implement in the field. Nutrient Expert (NE) was developed to provide crop advisors with a simpler and faster way to use SSNM. NE enables crop advisors to develop SSNM recommendations using existing site information. Nutrient Expert for Hybrid Maize (NEHM) increased yield and profit of farmers in Indonesia and the Philippines. In Indonesia, NEHM increased yield by 0.9 t ha⁻¹, which increased profit by US$ 270 ha⁻¹ over farmer’s fertilizer practice (FFP). Compared with FFP, NEHM recommendations reduced fertilizer P (−4 kg ha⁻¹), increased fertilizer K (+11 kg ha⁻¹), and did not significantly change fertilizer N. In the Philippines, NEHM increased yield by 1.6 t ha⁻¹ and profit by US$ 379 ha⁻¹ compared with FFP. Compared with FFP, NEHM gave higher rates of all three nutrients (+25 kg N ha⁻¹, +4 kg P ha⁻¹, and +11 kg K ha⁻¹), which substantially increased fertilizer costs (US$ 64 ha⁻¹) but still increased profit by about six times the additional investment in fertilizer. NE accounts for the important factors affecting site-specific recommendations, which makes it a suitable starting point for developing nutrient management tools to reach more users.