ABSTRACT

Manufacturing molds for plastic parts injection are a particular machining domain, where challenging materials, like AISI P20 steel, are forced to satisfy the highest surface quality requirements. Before mirror polishing, milling operation is a common and challenging task due to drilling and milling with the same tool. Thus, special cutting tools, like asymmetric indexable type, are often used. This tool presents two geometrically equal positive inserts – one placed horizontally and the other vertically – for the flexible machining of holes, cavities, floors, and walls. Rough-medium milling operations lead to a complicated relationship between cutting conditions and geometrical tool parameters, making it challenging to balance the tool life of both inserts. The novelty of this work is to propose a model for cutting force prediction with an asymmetric tool to explain the separated behavior of both inserts and determine a better compromise between cutting conditions and tool life. The experimental tests were done for model validation and then wear cutting tests for testing improved cutting conditions. The results predicted by the model proved that by changing the depth of cut from 0.3 mm to 0.8 mm, the wear in both inserts was more balanced, increasing chip volume up to 1.7 times.

摘要

塑料零件注射制造模具是一个特殊的加工领域，其中具有挑战性的材料，如 AISI P20 钢，被迫满足最高的表面质量要求。在镜面抛光之前，由于使用相同的刀具进行钻孔和铣削，因此铣削操作是一项常见且具有挑战性的任务。因此，经常使用特殊的切削刀具，如非对称可转位刀具。该刀具提供了两个几何形状相等的正刀片 - 一个水平放置，另一个垂直放置 - 用于灵活加工孔、腔、地板和墙壁。粗-中等铣削操作导致切削条件和几何刀具参数之间的复杂关系，使得平衡两种刀片的刀具寿命具有挑战性。这项工作的新颖之处在于提出了一种使用非对称刀具进行切削力预测的模型，以解释两种刀片的分离行为并确定切削条件和刀具寿命之间的更好折衷。实验测试用于模型验证，然后磨损切削测试用于测试改进的切削条件。模型预测的结果证明，通过将切削深度从 0.3 毫米更改为 0.8 毫米，两个刀片的磨损更加平衡，切屑量增加了 1.7 倍。