Productivity and Superficial Quality of an Aspherical Die Using CAD/CAM

ABSTRACT Nowadays, it is hard to imagine modern industry without the manufacturing and design software aided by computer, known as CAD/CAM, once the search for excellence in complex geometry parts, reduced time, quality assurance and interchangeability is increasing. Within this quest, the CAD/CAM platform has become a significant factor in manufacturing, especially on complex surfaces parts, mainly because of superficial quality, reliability and product competitiveness. Defined as surface within one or more non-flat surfaces or non-square, usually represented by parametric models, the freeform surfaces are very complex, requiring the control of three or more axes simultaneously, making the CAM tool indispensable. Tests were carried out by milling of aspherical cavities, on VP100 steel samples, with cemented carbide ball nose inserts with TiAlN coating. Two cutting strategies – zig-zag and spiral – and two finishing (CAM) strategies – parallel plans and Z level – were also investigated. Final Surface quality, tool productivity and tool wear were related to machining time, surface roughness (Ra, Rz, Rku and Rsk) and tool wear (VBmax). Results showed that the chosen strategy (tool path) it is the main factor to productivity.

摘要：现如今，现代工业已难以脱离计算机辅助制造与设计软件（CAD/CAM）——当下对复杂几何零件的精度优化、加工时长缩减、质量保障及互换性的要求日益提升。在此背景下，CAD/CAM平台已成为制造业的关键要素，在复杂曲面零件加工领域尤为突出，这主要得益于其可保障加工表面质量、提升系统可靠性与产品竞争力。自由曲面（freeform surfaces）被定义为包含一个或多个非平面或非矩形曲面的结构，通常以参数化模型进行表征，这类结构极为复杂，需同时控制三轴及以上轴系运动，因此计算机辅助制造（CAM）刀具已成为不可或缺的加工工具。本次研究采用TiAlN（氮化钛铝）涂层硬质合金球头铣刀，对VP100钢试样上的非球面型腔开展铣削加工试验，同时考察了两种切削策略：往复式（zig-zag）与螺旋式（spiral），以及两种CAM精加工策略：平行平面式与Z向分层式（Z level）。研究将最终加工表面质量、刀具生产效率与刀具磨损量与加工时长、表面粗糙度（Ra、Rz、Rku、Rsk）以及刀具最大磨损量（VBmax）进行关联分析，结果表明，所选定的加工策略（刀具路径）是影响生产效率的核心因素。