Novel Experimental Set-Up to Investigate the Wear of Coatings for Sheet Metal Forming Tools

Abstract

The use of PVD and CVD coatings has increased significantly thanks to the improved tribological performances they offer in many metalforming processes. Nevertheless the proper coating selection for a specific forming operation is not well established yet, being mainly based on trails and error approaches. The use of FEM-supported analyses may represent an effective support in the optimization of process parameters, but the need of testing procedures and reliable models to describe the mechanical and tribological phenomena at the interface between the dies and the workpiece is still significant. The paper presents a novel experimental set-up for the evaluation of the wear resistance of dies coatings in sheet metal forming operations. A progressive stamping process was taken as reference case and analyzed by numerical analyses. Contact pressures, temperatures and tangential loads at the tools-blank interface were evaluated in each deformation step. TiAlN and CrN were selected as reference coatings and deposited via magnetron sputtering technique. The first part of the research was focused on the design of the novel set-up capable to carry out controlled wear tests in laboratory environment, performed with the parameters obtained from the numerical simulation. The results of such experiments were compared to the ones from standard laboratory tests and with industrial trials, though measurements of loads, of surface roughness evolution and by surface investigations trough Scanning Electron Microscope observations.

A Comparative Study in the Tribological Behavior of DLC Coatings Deposited by HiPIMS Technology with Positive Pulses

“…In the case of standard parts, there are various partial solutions in terms of materials, and additional treatments in order to improve their properties and durability, which offer a highly contrasted stable behavior [14]. The importance of the continuous development of solutions to improve the performance of this type of tool is a key and essential factor for increasing the productivity of manufacturing processes [15]. According to this, different types of strategies such as chemical vapor deposition (CVD) or PVD coatings for high-load applications [16,17] were successfully developed, going from a combination of a thermochemical treatment (usually nitriding) with a thin layer obtained by cathodic-arc [18] to more recent strategies based on the combination of multilayers and composites of nanometric spacing [19,20].…”

Comparative Study of Tribomechanical Properties of HiPIMS with Positive Pulses DLC Coatings on Different Tools Steels

“…Despite showing a poor adhesion to the substrate, DLC coatings are gaining a lot of importance in the field of surface engineering-i.e., they have increased their share in the global market from USD 800 M to around USD 1.7 billion in the last decade and their revenue has been increasing with a compound annual growth rate of approximately 14% over the past 5 years [19]. They are gaining especial importance in the development of solutions to improve the performance of cutting and forming tools [8,9,20] by improving their properties and durability and, hence, increasing the productivity of manufacturing processes [21].…”