Journal of Manufacturing Processes ( IF 6.2 ) Pub Date : 2020-03-30 , DOI: 10.1016/j.jmapro.2020.03.024 Ashwani Pratap , Karali Patra
Capability of sintered micro-grinding tool is limited by low chip space, ineffective lubrication access and premature loading which results in high cutting forces and brittle mode fractures on the work surfaces. Usage of textured tool is one of the methods to avoid aforesaid phenomena and to achieve high cutting performance. On machine fabrication of textured micro-tools and correlating their cutting mechanism with texture dimension are some of the primary challenges. A new electric discharge texturing method for on-machine fabrication of textured tools is devised and the tools with optimum intermittent ratio but varying texture dimensions are fabricated. Micro-grinding experiments are carried out on BK7 glass to establish the correlation between cutting performance with texture dimension, cutting parameters and MQL (minimum quantity lubrication) pressure. It is concluded that tool with small size and large number of texture units reduced the cutting forces, surface roughness and edge chipping by 25–35 % of those obtained by a tool without texture at depth of cut 10 μm and feed rate 5 mm/min. The amount of reductions of these two process parameters even reached to 50–60 % at high depth of cut 40 μm and feed rate 11 mm/min. The reduction in output parameters is supported by the observation of effective migration of chips in the passive areas. It is also established in this study that MQL spray droplet size should be very close to the texture dimension to ensure maximum cutting fluid access in the machining zone. Analytical derivation of penetration depth for textured tools indicated delayed chances of ductile to brittle transition when the tools with small size texture units are used in place of the tools with large size texture units.
中文翻译:
工具表面纹理,切削参数和最小润滑量(MQL)压力对BK7玻璃微研磨的综合影响
较小的切屑空间,无效的润滑通道和过早的载荷会限制烧结微磨具的功能,这会导致较高的切削力和工作表面的脆性断裂。使用网纹工具是避免上述现象并实现高切削性能的方法之一。在机器上制造带纹理的微型工具并使它们的切割机制与纹理尺寸相关联是一些主要的挑战。提出了一种新的用于纹理化工具在机加工的放电纹理化方法,并制造出具有最佳间歇比但纹理尺寸可变的工具。在BK7玻璃上进行了微研磨实验,以建立切削性能与织构尺寸之间的相关性,切削参数和MQL(最小量润滑)压力。结论是,具有小尺寸和大量纹理单元的工具将切削力,表面粗糙度和边缘碎裂比那些在切削深度10μm和进给速度5 mm / min时没有纹理的工具减少了25–35% 。在高切削深度40μm和进给速度11 mm / min时,这两个工艺参数的减少量甚至达到了50-60%。通过观察无源区域中芯片的有效迁移,可以支持减少输出参数。在这项研究中还确定,MQL喷雾液滴的尺寸应非常接近纹理尺寸,以确保在加工区域内最大程度地进入切削液。