A General Review of the Power Screw Drive Failure Modes: Origins, Mechanisms & Solutions

Power screw drives are machine components that convert the rotative motion into a translation one with usually improved efficiencies and very high "Load to Torque" ratios, thus, often in very compact volumes. Usually made of hardened and grounded carbon steels, "bearing steels", low to medium alloyed rolled and/or hardened steels they are also manufactured out of non metalics (f.e. Bronze Rg7) but also, in the recent years, out of "high tech engineered polymers". As machine members submitted to various loading histories, speeds and acceleration, temperature and environmental influences, they may exhibit different failure modes involving fracture, corrosion, fatigue (superficial and volumic), wear and some other miscellaneous effects linked with their structure or the environment they are working in. As those machine-elements are important, not very well known in their specific technical details, but anyway, found in a wide range of industry sectors and machineries (Heavy casting or rolling devices, packaging units, aerospace, pharmaceutics & medical, water work, ...), the goal of this talk is to make, as the Failure Analyst informed of some of the potential issues seen in the industry, as the Designer aware about checks they need to preview for preventing their failures. After an overview of the main materials, heat & surface treatments exploited in these solutions, the main failure modes met in the industry will be reviewed through a practical Atlas of Typical failure patterns, their main failure mechanisms briefly explained and some solution draws-ups further emphasized.