Investigation of Multiparameter Laser Stripping of AlTiN and DLC C Coatings.

Tomáš Primus,Pavel Zeman,Martin Šorm,Pavel Kožmín,Adam Čermák,Jan Brajer,František Holešovský,Josef Hlavinka

doi:10.3390/ma14040951

Tomáš Primus, Pavel Zeman + Show 6 more

Open Access

https://doi.org/10.3390/ma14040951

Copy DOI

Abstract

The lifetime and properties of cutting tools and forming moulds can be prolonged and enhanced by the deposition of hard, thin coatings. After a certain period of usage, the coating will deteriorate. Any remaining coating must be removed prior to successful recoating. Laser stripping is a fast and environmentally friendly coating removal method. In this paper, we present laser removal of two types of coatings deposited on a 1.2379 tool steel substrate, namely, an AlTiN coating with high hardness and a DLC C coating with a small coefficient of friction (COF). A powerful nanosecond laser was employed to remove the coating from the substrate with high efficiency, along with suitable residual surface roughness. Measurements were taken of surface roughness, removed depth, and working time on a stripped area of 1 cm2. The samples were evaluated under a microscope, with a 3D profilometer, and by EDS chemical analysis. Successful removal of the coating was confirmed by optical analysis, but detailed chemical characterisation showed that about 30% of the coating element may remain on the surface. Moreover, a working time of less than 7.5 s per cm2 was obtained in this study. In addition, it was shown that the application of a second low energy, high frequency laser beam pass leads to remelting of the peaks of the material and reduced surface roughness.

Highlights

To increase manufacturing efficiency, cutting tool and mould surfaces are covered with different types of thin, hard coatings [1]
The aim of this paper is to present a method of laser stripping for highly productive removal of hard coatings, namely, AlTiN
The amount ofwas carbon was higher than 15%, the amount of chromium varied in from a highly productive with oneoflaser beamwas pass,around resulting in for good quality

Summary

Introduction

To increase manufacturing efficiency, cutting tool and mould surfaces are covered with different types of thin, hard coatings [1]. After tools incur damage from cutting processes, they can be sharpened and reused, but no coating residue should remain. Proper coating removal is important for successful sharpening, redeposition of a new coating, and the final properties of the reground and recoated tool [2]. Coatings are used as a protective barrier against wear, friction, abrasion, adhesion and thermal damage [4]. Some coatings can decrease friction, increasing tool lifetime [5]. Coatings frequently include TiN, which increases wear resistance. Coatings consisting of AlTiN have a high hardness. CrN is another type of coating, which increases corrosion resistance and provides lubricity [2]

Objectives

Methods

Results

Discussion

Conclusion