Wear Behavior of Uncoated and Coated Tools in Milling Operations of AMPCO (Cu-Be) Alloy

Vitor F C Sousa,Andresa Baptista,Francisco J G Silva,Gustavo Pinto,João Castanheira,José S Fecheira

doi:10.3390/app11167762

Abstract

Copper-Beryllium alloys have excellent wear resistance and high mechanical properties, they also possess good electrical and thermal conductivity, making these alloys very popular in a wide variety of industries, such as aerospace, in the fabrication of tools for hazardous environments and to produce injection molds and mold inserts. However, there are some problems in the processing of these alloys, particularly when these are subject to machining processes, causing tools to deteriorate quite rapidly, due to material adhesion to the tool’s surface, caused by the material’s ductile nature. An assessment of tool-wear after machining Cu-Be alloy AMPCOLOY 83 using coated and uncoated tools was performed, offering a comparison of the machining performance and wear behavior of solid-carbide uncoated and DLC/CrN multilayered coated end-mills with the same geometry. Multiple machining tests were conducted, varying the values for feed and cutting length. In the initial tests, cutting force values were registered. The material’s surface roughness was also evaluated and the cutting tools’ edges were subsequently analyzed, identifying the main wear mechanisms and how these developed during machining. The coated tools exhibited a better performance for shorter cutting lengths, producing a lower degree of roughness on the surface on the machined material. The wear registered for these tools was less intense than that of uncoated tools, which suffered more adhesive and abrasive damage. However, it was observed that, for greater cutting lengths, the uncoated tool performed better in terms of surface roughness and sustained wear.

Highlights

Copper-Beryllium alloys have seen application in a great variety of industries, such as aeronautics and aerospace [1], molds, and other applications that are subject to hazardous conditions
There have been some studies about the processing of these alloys for injection mold applications, primarily directed at the electrical discharge machining of these copper-based alloys, as this process proves very useful in producing mold cavities [4]
Regarding the surface roughness of the machined part, it was clearly noticed that the feed rate had a high influence on this parameter, with values of surface roughness increasing by up to four times from the feed rate of 750 mm/min to 1500 mm/min

Summary

Introduction

Copper-Beryllium alloys have seen application in a great variety of industries, such as aeronautics and aerospace [1], molds, and other applications that are subject to hazardous conditions These alloys are preferred over other copper alloys due to their good conductivity and strength [2], making them ideal for industrial mold applications, as their high thermal conductivity can reduce injection molding cycles by up to 80% [3]. There have been some studies about the processing of these alloys for injection mold applications, primarily directed at the electrical discharge machining of these copper-based alloys, as this process proves very useful in producing mold cavities [4] This process is suitable for the machining of high-strength and high ductility alloys, as it does not cause any distortion during machining. It would be quite useful to employ other types of processes in the production of molds and mold inserts, made from these copper-based alloys, especially copper-beryllium

Methods

Discussion

Conclusion