Increasing the safety against scuffing of additive manufactured gear wheels by internal cooling channels

Abstract

The layer-by-layer principle of the additive manufacturing (AM) technology of Laser-Powder-Bed-Fusion (LPBF) creates new opportunities in the design and manufacturing of efficient gear components. For example, integrating a cooling system can increase the safety against scuffing or reduce the amount of required lubrication and thus the splashing losses. Quenched and tempered steels or case-hardened steels are commonly used in the fabrication of gear components. However, the availability of these alloys for LPBF processing is still limited. The development of suitable LPBF metal gears (with a Gear Research Centre (FZG) type A geometry) out of quenched and tempered 30CrNiMo8 steel with internal cooling channels shows the possibility of significantly increasing the safety factor against scuffing. This work includes the development of a suitable cooling strategy, material development, the setup of a suitable test infrastructure and the analysis of the LPBF gears tested for scuffing.

Metal Additive Manufacturing (MAM) Applications in Production of Vehicle Parts and Components—A Review

“…By using appropriate structures, it is possible to produce lightweight gears while still maintaining the required strength properties [95,96]. Additive manufacturing techniques can facilitate the production of internal channels, which may enhance heat dissipation and ensure sufficient lubrication of friction surfaces [97,98]. Figure 13 shows an example of a gear produced using the SLM technique and SS-316L steel [89].…”

Influence of discrete laser surface melting on scuffing resistance of W6Mo5Cr4V2 steel gear

“…Once hot scuffing occurs in gears, gear pair vibration noise and power loss markedly escalate. In terms of gear enhancement, three primary approaches exist to strengthen antiscuffing capability: (1) Adjusting geometric parameters through methods like tooth tip correction [2] and tooth profile modification [3]; (2) Leveraging advanced gear manufacturing technologies, including powder metallurgy [4] and laser powder bed fusion additive manufacturing [5]; (3) Employing various tooth surface strengthening processes such as tooth surface grinding [6], diamond-like carbon (DLC) coating [7][8][9][10], physical vapor deposition [11], and composite material coating [12,13]. A comparative analysis was conducted to review the current research status.…”

“…• Grain Refinement: Refined grains effectively alleviated stress concentration within the material, thereby reducing the probability of fatigue crack initiation in gears [8,10]. Fine grains increased the dislocation density of materials, enhancing their yield strength and tensile strength, which improved gears' resistance to plastic deformation [5]. Grain refinement also improved the hardness of tooth surfaces, directly affecting gears' ability to resist wear and pitting [6,10].…”

“…• Surface Roughness: Increased surface roughness exacerbated noise and vibration during gear transmission, because the protruding contact points on the tooth surface led to poor contact between gear pairs [5]. During gear meshing, rough tooth surfaces increased the friction coefficient, thereby exacerbating wear [10].…”

Process-Integrated Lubrication in Sheet Metal Forming

“…Furthermore, additive manufacturing is also characterized by a high degree of functional integration [12,17]. In addition to reducing the number of parts, local effects such as thermal, electrical, magnetic, damping and lubrication are increasingly integrated into components [13,[18][19][20][21][22][23]. As a result of the improved component performance, the costs related to the entire product life cycle can also be saved [24].…”