Characterization of Tool Wear in High-Speed Milling of Hardened Powder Metallurgical Steels

Fritz Klocke,Gustavo Francisco Cabral,Kristian Arntz,Marc Busch,Martin Stolorz

doi:10.1155/2011/906481

Fritz Klocke, Gustavo Francisco Cabral + Show 3 more

Open Access

https://doi.org/10.1155/2011/906481

Copy DOI

Abstract

In this experimental study, the cutting performance of ball-end mills in high-speed dry-hard milling of powder metallurgical steels was investigated. The cutting performance of the milling tools was mainly evaluated in terms of cutting length, tool wear, and cutting forces. Two different types of hardened steels were machined, the cold working steel HS 4-2-4 PM (K490 Microclean/66 HRC) and the high speed steel HS 6-5-3 PM (S790 Microclean/64 HRC). The milling tests were performed at effective cutting speeds of 225, 300, and 400 m/min with a four fluted solid carbide ball-end mill ( = 6, TiAlN coating). It was observed that by means of analytically optimised chipping parameters and increased cutting speed, the tool life can be drastically enhanced. Further, in machining the harder material HS 4-2-4 PM, the tool life is up to three times in regard to the less harder material HS 6-5-3 PM. Thus, it can be assumed that not only the hardness of the material to be machined plays a vital role for the high-speed dry-hard cutting performance, but also the microstructure and thermal characteristics of the investigated powder metallurgical steels in their hardened state.

Highlights

The machining of these superhard steels by multiaxis milling represents a major challenge and is, an issue of highest interest, both for the scientific research and the industrial production [2,3,4,5]. Due to their sophisticated material properties, such as their high hardness, ductility, and pressure strength [4], they can be loaded up to high mechanical stresses. This represents a central requirement for high-value parts and components, as they occur in different areas of application in the tool and die making; see Figure 1
The effective cutting speed was calculated on the surface generating area of the chip, which is the area where the actual cut generates a final surface which is not recut in the following tool engagement
(3) Depending on the material characteristics of the investigated work piece materials, in a narrow cutting parameter range an increased federate was accompanied by an enhanced tool life

Summary

Introduction

In the economically efficient large batch production of complex functional and structural components, the moulding and forming technologies are of crucial importance. The performance of these technologies is significantly defined by the material, the surface conditions, and the subsurface integrity of the manufactured tools, dies, and moulds. The machining of these superhard steels by multiaxis milling represents a major challenge and is, an issue of highest interest, both for the scientific research and the industrial production [2,3,4,5] Due to their sophisticated material properties, such as their high hardness, ductility, and pressure strength [4], they can be loaded up to high mechanical stresses. This represents a central requirement for high-value parts and components, as they occur in different areas of application in the tool and die making; see Figure 1

Objectives

Methods

Results

Conclusion