The dimensional accuracy of fused deposition modeling (FDM) machines is dependent on errors caused by processing parameters and machine motions. In this study, an integrated error model combining these effects is developed. Extruder temperature, layer thickness, and infill density are selected as parameters of this study for three FDM machines, namely, Flashforge Finder, Ultimaker 2 go, and XYZ da Vinci 2.0 Duo. Experiments have been conducted using Taguchi method and the interactions between processing parameters are analyzed. Based on the dimensional deviations between fabricated parts and the computer aided design (CAD) geometry, a set of coefficients for the integrated error model are calculated to characterize each machine. Based on the results of the integrated error model, the original CAD geometry is optimized for fabrication accuracy on each machine. New parts are fabricated using the optimized CAD geometries. Through comparing the dimensional deviations of parts fabricated before and after optimization, the effectiveness of the integrated error model is analyzed and demonstrated for the three FDM machines.

Day by day the application of thread milling process is enhancing in industry because of its inherent advantages over other thread cutting techniques. The current study dwells on the interference issue, which is generated during thread milling. It was observed that there are two sources of interference on the thread produced, i.e., interference induced during mill penetration and during full machining. This interference leads to an overcut on the thread; thus, it produces a dimensionally inaccurate thread. The interference produced by penetration is much more when compared to interference generated during full machining of thread. Thus, there is a pressing need to analyze interference during penetration. So, this study evaluates different applied penetration strategies and the level of interference produced. Further, the study suggests modified penetration strategies in order to reduce the interference produced and hence create more accurate thread. This investigation is supported by analytical modeling and experimental exploration.