Method to Increase the Accuracy of Large Crankshaft Geometry Measurements Using Counterweights to Minimize Elastic Deformations

Abstract

<jats:p>Large crankshafts are highly susceptible to flexural deformation that causes them to undergo elastic deformation as they revolve, resulting in incorrect geometric measurements. Additional structural elements (counterweights) are used to stabilize the forces at the supports that fix the shaft during measurements. This article describes the use of temporary counterweights during measurements and presents the specifications of the measurement system and method. The effect of the proposed solution on the elastic deflection of a shaft was simulated with FEA, which showed that the solution provides constant reaction forces and ensures nearly zero deflection at the supported main journals of a shaft during its rotation (during its geometry measurement). The article also presents an example of a design solution for a single counterweight.</jats:p>

The Effect of Deflections and Elastic Deformations on Geometrical Deviation and Shape Profile Measurements of Large Crankshafts with Uncontrolled Supports

“…It was moved angularly to the defined starting position. Detailed description of the experimental system was presented in [ 2 , 11 ].…”

“…The error analysis elaborated in [ 2 , 10 , 11 , 12 ] is particularly useful for issues related to a specific group of large machine components with cylindrical assemblies [ 13 ], such as large crankshafts of ship engines. Such shafts have large masses and dimensions, and are also flaccid, have low and variable rigidity, and are susceptible to flexural deformation [ 14 , 15 ].…”

“…Misalignment occurs when the shape and geometry of manufactured items deviate from their theoretical designs, and such geometrical quantities should be correctly characterized. If shaft journals are supported by a set of fixed, rigid vee-blocks, this type of displacement is limited by unintentional preliminary deflections, resulting in incorrect measurements of geometric quantities [ 11 ].…”

“…The latest study [ 11 ] describes the use of temporary counterweights during large crankshaft measurements and presents the specifications of the measurement system and method to stabilize the forces at the supports that fix the shaft during measurements. The study showed that the proposed solution provided constant reaction forces and ensured nearly zero deflection at the supported main journals of a shaft during its rotation (during its geometry measurement).…”

Remanufacturing System with Chatter Suppression for CNC Turning

“…In the machining industry, the key stage is to make a part from the blank. For this process, qualified CNC operators with extensive knowledge of G-code machining and programming technology are required, especially in view of the increasing demands concerning: machining time, surface quality [ 10 ], topographic control and continuous miniaturization, for which micrometers accuracy is required [ 11 ]. The machining of new polymer materials injected [ 12 ] or printed [ 13 ] is also a major challenge for operators.…”