Experimental Investigation of the Wear Behaviour of Coated Polymer Gears

Abstract

A comprehensive experimental investigation of the wear behaviour of coated spur polymer gears made of POM is performed in this study. The three physical vapour deposition (PVD) coatings investigated were aluminium (Al), chromium (Cr), and chromium nitrite (CrN). Al was deposited in three process steps: By plasma activation, metallisation of Al by the magnetron sputtering process, and by plasma polymerisation. Cr deposition was performed in only one step, namely, the metallization of Cr by the magnetron sputtering process. The deposition of CrN was carried out in two steps: the first involved the metallization of Cr by the magnetron sputtering process while the second step, vapour deposition, involved the reactive metallisation of Cr with nitrogen, also by the magnetron sputtering process. The gears were tested on an in-house developed testing rig for different torques (16, 20, 24 and 30 Nm) and rotational speed of 1000 rpm. The duration of the experiments was set to 13 h, when the tooth thickness, and, consequently, the wear of the tooth flank was recorded. The experimental results showed that the influence of metallisation with aluminium, chromium, and chromium nitrite surface coatings on the wear behaviour of the analysed polymer gear is not significant. This is probably due to the fact that the analysed coatings were, in all cases, very thin (less than 500 nm), and therefore did not influence the wear resistance significantly. In that respect, an additional testing using thicker coatings should be applied in the further research work.

Noise Evaluation of Coated Polymer Gears

“…of the analysed polymeric component. As already presented by the authors of this paper [ 1 ], the influence of very thin PVD-coatings (less than 500 nm) on the wear behaviour of POM polymer spur gears is small and does not reduce the wear significantly. For that reason, the multilayer (thicker) PVD-coatings made of Al, Cr, and CrN should be considered in the future.…”

“…Polymer gears are used widely in many engineering applications, such as office appliances, mechatronic devices, household facilities, and medical instruments [ 1 , 2 , 3 ]. They can operate without lubrication and, therefore, may be used in some typical applications where lubrication is not desired (household appliances, the food industry, medicine, etc.).…”

Comprehensive Areal Geometric Quality Characterisation of Injection Moulded Thermoplastic Gears

“…Polymer gears can be produced by classical cutting processes or, for large series production, by injection moulding [12]. Injection moulding is a specific gear production process that results in distinct types of gear geometry deformations [13]. If the process parameters are unsuitable, these deformations can be very substantial and can seriously influence the polymer gear's service life.…”

Wear Behaviour of Multilayer Al-PVD-Coated Polymer Gears

“…In the authors’ previous work [ 52 ], we analysed the fatigue behaviour of coated spur polymer gears, where only one coating layer was investigated, made of aluminium (Al), chromium (Cr), or chromium nitride (CrN). The experimental results showed that the influence of Al, Cr, or CrN surface coatings on the wear behaviour of the analysed polymer gear was not significant.…”