摘要
超硬刀具在现代机械制造业中占有重要的地位。随着汽车、轨道客车、飞机、机床、船舶等制造业的飞速发展，新型复合材料不断得到应用，以及现代加工业的高速、高效、高精密的加工特点对刀具的抗冲击性能提出了更高的要求，同时促进了超硬刀具行业的发展，金刚石、立方氮化硼等超硬刀具已经普遍使用。但超硬刀具的抗冲击性能较差，特别是断续切削加工和铣削加工以及宽切削刃加工时，容易出现崩刃现象，研究刀具制作工艺和刃口强化技术具有重要意义。工业机器人装配
本文优化了金刚石刀具、立方氮化硼刀具及砂轮修整工具的制作工艺。分析了刀具在使用过程中的主要破损形式。首次采用高压纳米金刚石粉磨料水射流抛光技术对超硬刀具刃口进行强化处理，取得明显效果。主要内容如下：
1、采用行业内常用的方法制作了CBN刀片。针对某企业加工汽车油泵中心轴端口的DNGA150404—BN型号刀片，进行了负倒棱和倒钝的刃口强化处理，倒棱宽度0.2 mm，倒棱角度15°，在涂有1-3μ金刚石微粉的毛毡轮上为负倒棱刀片下方刃口做钝化处理。该加工工艺属淬硬钢工件断续切削加工。使用结果表明，钝化后的刀片加工零件数量提高了30%左右。
2、制作了PCD金刚石复合片刀具，型号为XPHW160406的铣刀片，用于汽车油泵大平面铣削加工。属高硅铝合金材料的断续加工。使用结果表明，工件表面粗糙度可达到R a0.2 μm以下，完全满足要求。
刀具破损形式主要是微崩刃。
研究了单晶金刚石刀具的制作工艺，实现了单晶金刚石与硬质合金的牢固焊接，建立了单晶金刚石刀具的刃口刃磨工艺。采用金刚石砂轮进行粗磨、半精磨和精磨，采用研压金刚石微粉的铸铁磨盘进行超精磨。得到锋利的单晶金刚石刀具刃口。在高硅铝合金的加工中，制作的型号为CCGW09T304单晶金刚石刀具，破损的形式主要是崩刃。与PCD刀具相比，零件的表面粗糙度明显降低，使用寿命提高不明显。原因可能是工件材料有较多的硬质点，导致崩刃。
研究了带有负倒棱的单晶金刚石轮毂刀制作工艺。自行设计制作了专用于制作轮毂刀负倒棱的工装卡具。该卡具可与BDM-901刃具磨床配套使用，能够实现任意角度的负倒棱制作，倒棱均匀。使用结果表明，加工工件数量2800个左右，寿命只能达到进口刀具的60%~70%。
3、以CVD金刚石条为原料，采用冷压成型与热压烧结的工艺制作了砂轮修整工具，优化了制作工艺。通过模具设计，制作了金刚石条倾斜45°整齐排列的砂轮修整片，使金刚石排列更合理，更牢固地镶嵌。金刚石条不易断裂，性能更加稳定。采用7条0.8×0.8×4 mm的CVD金刚石条制作的BFO20*7R025的修整片替代天然金刚石成型刀，寿命提高了1倍。
4、为了强化超硬刀具刃口，首次搭建了高压纳米金刚石磨料水射流抛光系统，初步建立了超硬刀具的刃口强化工艺。研究了喷射压力、喷射角度对硬质合金和金刚石材料面与棱角抛光效果的影响，结
果表明喷射压力和角度对硬质合金的表面粗糙度影响不大，对材料的去除效率影响较大。当喷射角为15°、压力10 MPa时，硬质合金可以达到较好的抛光效果。低压力下PCD刀具前刀面无明显变化，20 MPa时，能够实现PCD金刚石表面材料的微量去除。抛光质量随喷射角度增大而提高，但材料去效率会降低。当喷射角为75°、压力20 MPa抛光PCD刀具刃口时，可以使刃口变得光亮圆滑，起到强化刃口的作用。
关键词：
蚊子网
CBN，PCD，超硬工具，射流抛光，刃口强化，工艺参数
Abstract
Superhard tools play an important role in modern machine manufacturing. With the rapid development of automobile,rail passenger car, airplane,machine tool, ship etc, new composite materials have been applied extensively. And the characteristics of high speed,high efficiency and high precision in the modern processing industry propose higher requirements for impact resistance of cutting tools, and in the meantime promote the development of superhard tool industry. Superhard tools such as diamond tools,cubic boron nitride(CBN) tools etc have been widely used. However, the impact resistance of superhard tools is poor, and tipping can easily occur in intermittent cutting, millin
QDFILMg processing and wide cutting edge processing. So it is very significant to study the fabrication process and edge strengthening technology of cutting tools.
This paper optimizes the fabrication process of diamond tools, CBN tools and grinding wheel dressers, and analyzes the main modes of tool damage during use. For the first time, high pressure nano-diamond powder abrasive water jet (AWJ) polishing technology is used to strengthen the edge of superhard cutting tools, and the effect is obvious.The main contents are as follows:
双层水晶玻璃杯
1. CBN blades are fabricated using common methods in the industry. The DNGA150404—BN blade, which is used to process the automobile oil pump central axis, is edge strengthened with negative chamfer and sharp edge smoothing. The chamfer width is 0.2mm, and the chamfer angle is 15°. The edge of the blade is passivated in the wool wheel coated with 1-3u diamond micro-powder. This process is hardened steel intermittent cutting. The application results show that the number of the workpiece that the blade can process increases by about 30 percent after edge preparation.
管道防爬刺2. This paper fabricates the XPHW160406 milling insert, which belongs to the PCD diamond compact cutting tool and is used in milling processing of automobile oil pump large plane. The processing is intermittent cutting of high-silicon aluminum alloy. The application results show that the surface roughness of the workpiece can
reach below R a0.2 μm, which can fully meets the requirements. And the main form of tool damage is tipping.
The fabrication process of single crystal diamond tool is studied, and the firm welding of single crystal diamond and cemented carbide is achieved. The edge grinding process of single crystal diamond tool is established. Diamond wheel is used for coarse grinding, semi-finish grinding and finish grinding, and the cast iron refiner plate grinding diamond powder is used for ultra-precision grinding. Thus we get sharp edge of single crystal diamond tool. In the process of high-silicon aluminum alloy, for the CCGW09T304 single crystal diamond tool, tipping is till the main damage form. Compared with PCD tools, the surface roughness of the workpiece decreases obviously, and the tool life increases not significantly. We think the cause might be that the workpiece has many hard spots.
The fabrication process of single crystal diamond hub cutting tool with negative chamfer is studied. Special clamp is designed to fabricate the negative chamfer of the hub cutting tool. The clamp can work well with the BDM-901grinder, and can fabricate negative chamfer at any angle, and the chamfer is uniform. The application results show that it can process 2800 workpieces or so and that its life is only 60 to 70 percent of that of cutting tools imported.
3. Using CVD diamond strip as raw material, we fabricate the grinding wheel dresser with the technology of cold briquetting and hot pressing and optimize the fabrication process. Through mould design, we fabricate grinding wheel dresser with diamond strips inclining at 45degree neatly. The diamond strips rank more reasonably, are inlayed more firmly, and not easily break, so the performance is more stable. We fabricate BFO20*7R025 grinding wheel dresser using 7 CVD diamond strips whose size is 0.8×0.8×4 mm. When we replace the natural diamond molding cutter with the grinding wheel dresser, the tool life is extended by 100 percent.
4．To strengthen the edge of superhard cutting tools, a high-pressure nano diamond abrasive water jet polishing system is built and preliminary edge strengthening technique is established. This paper studies the influence of the water jet pressure and jet impact angle on the polishing effect of the cemented carbide and
diamond material surface and edges. The results show that the water jet pressure and jet impact angle have little influence on surface roughness, but have great influence on material’s removal efficiency. When the jet angle is 15°and the pressure is 10MPa, cemented carbide can be polished better. The rake face of PCD cutting tools has no significant change under low pressure. In the pressure of 20MPa, PCD diamond surface material can be removed little. When polished at a jet imp
act angle of 75 degree and a pressure of 20 MPa, the edge of PCD cutting tool can be bright and smooth, and be strengthened.
Keywords:
折叠篮
CBN, PCD, superhard tools, jet polishing, edge strengthening, process parameters
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