Complex surfaces such as helical ones are commonly used in machinery. Such surfaces can be obtained by various machining processes, one of these processes being thread whirling. The influence of machining conditions needs to be better understood to develop a more precise prediction of the specific resulting errors involved in thread whirling. This paper firstly presents the theoretical conditions which generate micro-deviations on whirled surfaces. A theoretical model which considers the geometrical parameters describing the whirling head and cutters and the process’s whole kinematics was developed. The threaded surface was described as a complex compound surface resulting from intersecting successive ruled helical surfaces corresponding to the cutting edges of the set of cutters from the whirling head. Numerical simulation results were exemplified and validation experiments were both designed and performed. Empirical mathematical models were established to highlight the influence of the input factors such as thread pitch and external diameter, the ratio between the diameter of cutters’ top edge disposal and the thread’s external diameter, the rotary speed of the whirling head, and the rotary speed of the workpiece on some accuracy elements and roughness parameters of the threaded surface.

The strength of a joint between the ends of one or more strips can be improved by making the contours of the joint into the shape of either the Greek letter omega or of a dovetail. From the point of view of industrial practice, it is of interest to study the behavior of these joints under stretching demands. The emergence and development of additive manufacturing processes for parts made of polymeric materials has led to the idea of conducting experimental tests to highlight the behavior of omega and dovetail-type joints during the tensile test. For the tensile testing of some test samples in which omega and dovetail joints were used, a Taguchi array of type L18 was employed, with eight independent variables, one variable with a two-level variation, and seven variables with variations on three levels. As independent variables, the type of joint, the couple of polymer materials used to make the two components of the joint, some characteristic dimensions of the joint contours, and some input factors in the 3D printing process were established. The values of average force and average displacement at the peak were considered output parameters. The experimental results were mathematically processed, determining empirical mathematical models of the second-degree polynomial type. These models highlight the influence exerted by the considered input factors on the values of the output parameters.

Different processing methods can change the physical–mechanical properties and the microgeometry of the surfaces made by such processes. In turn, such microchanges may affect the tribological characteristics of the surface layer. The purpose of this research was to study the tribological behavior of a test piece surfaces analyzing the changes on the values of the coefficient of friction and loss of mass that appear in time. The surfaces subjected to experimental research were previously obtained by turning, grinding, ball burnishing, and vibroburnishing. The experimental research was performed using a device adaptable to a universal lathe. Mathematical processing of the experimental results led to the establishment of power-type function empirical models that highlight the intensity of the influence exerted by the pressure and duration of the test on the values of the output parameters. It was found that the best results were obtained in the case of applying ball vibroburnishing as the final process.

The paper presents an approach upon some strategies for improving the effectiveness and efficiency of engineering design activities, respectively of CAD activities, discussions being made in relation with their expected effects upon the sustainability of product development process. Concepts and principles of collaborative design, axiomatic design, integration of design applications with manufacturing planning and technical data management aspects, design reuse etc. are discussed within the presented approach. Complex assembly modeling management issues are also discussed as case study.

Cam mechanisms, covering a large structural variety, are widely used in machinery, mainly as components of automated systems. Their functioning behavior is affected by negative dynamic phenomena determined by specific high velocities and acceleration rates. Within the various types of research on the dynamic behavior of cam mechanisms, this study addresses the need to clarify the influence of geometrical parameters and technological conditions on some indicators of the jump phenomenon in contact loss for a cam-follower mechanism. This particularly developed case study referred to a mechanism with a profiled grooved disk cam and oscillating follower. To highlight the influence of the cam-follower contact elasticity on the jump phenomenon, two dynamic models were developed: one considering rigid elements in contact and the second considering elastic cam-follower contact. The models were tested within a virtually simulated experiment, and the numerical simulation results evidenced the influence of input factors like the applied load on the mechanism, the clearance in the cam-follower kinematic pair, and the rotational speed of the cam, and the inertia moment was reduced to the follower on some indicators of the jump phenomenon. Validation FEA and experiments were performed, proving the reliable appropriateness of the dynamic model based on elastic cam-follower contact.

Various factors influence the dimensional accuracy in Fused Filament Fabrication (FFF). The kinematic system is a major influential factor, as the motion precision depends on the implemented solution. Kinematics have a direct influence on equipment costs. The FFF 3D printing market has abundant equipment options, from low-cost to high-end solutions. The filament extrusion precision and the shrinkage induced by the thermal contractions are other influential factors for the resulting parts' quality. Nowadays, the XYZ cube is the calibration benchmark. This cube is used to adjust the dimensional accuracy of the resulting parts. The deficiency with the calibration cubes is that they allow only the measurement of external dimensions, which makes the calibration useless when tolerancing the internal features or scaling. This paper discusses the limitations of the accuracy calibration method using the XYZ cube and possible solutions to overcome them.