Mechanical Error in Rapid Prototyping Processes: Analysis and Synthesis of Error Using Stochastic Approach

Clearances in the joints and tolerances on the link lengths of linkages may cause mechanical error of appreciable magnitude. In this work, a stochastic model has been developed for analysis and synthesis of mechanical error in different Rapid Prototyping (RP) processes. Tolerances and clearances have been assumed to be random variables. The mechanical error has been found for a grid of points on the work surface in the (Fused Deposition) FD and StereoLithography (SL) processes and analyzed. A synthesis procedure has been developed for allocating tolerances and clearances in RP processes. Stringent values of tolerances and clearances reduce the error at the tool tip. However, the cost of manufacturing and assembling such a machine may become prohibitive. The tolerances and clearances are optimally allocated for FD and SL processes so to restrict the mechanical error within the specified limits. The methodology presented here is useful to the researchers performing the analysis and synthesis of mechanical error in RP and other machines as well as for the manufacturers to reduce the cost of manufacturing the machines.