Without any difficult machining work, sintering services make it possible for engineering customers to acquire complex geometrical parts profiles. The detail-heavy components exit the powder metallurgy equipment as perfectly identical compaction densified metal elements. That, then, is a big part of a bearing manufacturer’s motivation for adopting sintering technology. Of course, there’s also that self-lubricating feature, which has been exhaustively covered in past posts.
Conventional Sintered Bearings: Baseline Advantages
Sintered bearings are made of compacted metal powders. Thanks to what’s essentially a machine-free process, PM produced rolling elements and bearing races exit their Green compaction dies as dimensionally accurate end products. Passed through the grain coalescing sintering stage, all compacted components assume a uniform microstructure, so the bearings they assemble into rarely exhibit processing flaws. Generally speaking, such defects are introduced by worn or defective machining stations, which isn’t the case when PM compacts are utilized. By the way, the seamless bearing components are mixed with additives and porosity enhancers. With a lubricant added to the atomized powder mix way back at the powder metal blending vessel, conventional sintered bearings do possess a self-lubricating feature.
Evolving Powder-Metallurgy Produced Bearings
Usually, when engineers talk about sintered bearings, there are certain assumptions. Customers assume these parts are simple bushings, which employ friction-less, self-lubricating linings. Alternatively, the bearing is a simple set of rolling elements, a series of ball bearings within a pair of concentrically arranged rings. However, there’s also a large range of complex-shaped bearings entering the market. Imagine a small brushed motor, a D.C. powered prime mover. With exotic metals and graphite linings filling out the device’s unique architectural layout, a more detail-oriented sintering process is required to facilitate the creation of such tiny shaft mounting systems. Capable of imparting more rolling element detail while keeping the grain of those moving parts fine and uniform, this type of processing environment calls for optimal compaction and sintering accuracy. No matter, thanks to new developments in the twin fields of die manufacturing technology and PM microstructure control, these tiny, intricately detailed bearing elements are now being produced en masse.
So, where are complex-shaped sintered bearings utilized? They’re the intricate devices that add special sleeving arrangements and shaft fittings on custom-designed shaft mounts. Then, shrunken smaller, intricate powder metallurgy produced bearings are used in the electronics sector. In medical equipment pumps, in CD ROM drives, and in tiny servo units, they provide grain-homogenized balance. Lighter than conventional rolling elements, thanks in part to an inbuilt capillary system, that same feature also adds an ingrained self-lubricating mechanism to intricate-profiled bearings, regardless of their size.