Engineering and manufacturing science

Ductile iron can acquire enhanced thermal and mechanical properties from austempering heat treatment. The present study aims to identify the function of different cutting parameters affecting machinability and to quantify its effects. Turning was performed to test machinability according to the ISO3685-1993 (E) standard. After austenitizing at 900 °C for 90 min, austempered ductile iron (ADI) specimens were quenched in a salt bath at 380 °C for 90 min. The cutting force signals along three directions were measured in real time, whereas flank wear and surface roughness were measured offline. For the cutting parameters, the cutting speed and depth of cut were varied, but the feed rate was kept constant. In the flank wear tests, machining length was corresponded to tool life. In addition, in order to find out the effect of cutting parameters on surface roughness (Ra), tangential force (Ft), and flank wear (VB) during turning, response surface methodology (RSM) was utilized by using exp...

— In Metal matrix composites, the Aluminium Matrix Composites are gaining increasing attention for applications in aerospace, defence and automobile industries. The purpose of the current Paper is therefore aimed at highlighting the focus of the current research scenario, in the field aluminium based hybrid composites, to explore the materials for automotive and aerospace applications; this is achieved with the help of stir casting technique. Stir casting is one of the novel methods to produce metal matrix composites with more uniform distribution of matrix and reinforcement constituents. This approach involves mechanical mixing of the reinforcement particulates/particles into a molten metal bath. A crucible is heated to malt aluminum metal, with a motor and blades is placed in the crucible that helps to get uniform molten metal. The reinforcement is poured into the crucible above the melt surface and at a controlled rate, to ensure a smooth and continuous feed. As the blades rotate at moderate speeds, it generates a uniform mixing of the reinforcement particles into the melts to produce homogenous composites. In this paper we discussed about construction and experimentation of stir casting setup for metal matrix composites.

The productivity of a manufacturing system is greatly influenced by the configuration of the manufacturing system. This paper examines the importance of configuration on productivity, and the improvements that can be obtained by bufferless parallel-serial configurations, ie multiple machining ...

In this paper, a method is presented for the determination of the differences between the worm gear tooth surface processed by an oversized hob of finite number of teeth or by a flying tool, and the theoretically required gear tooth surface. The influence of hob oversize and machine tool settings on tooth contact pressure and transmission errors is determined. The full geometry and kinematics of gear tooth processing by an oversized hob or by a flying tool is included. The theoretical background is implemented by a computer program. By using this program, the influence of relevant design parameters of the worm gear set and the hob and of machine tool settings on processed gear tooth errors and on loaded tooth contact of the worm gear pair is investigated and discussed.

Friction stir blind riveting (FSBR) process offers the ability to create highly efficient joints for lightweight metal alloys. During the process, a distinctive gradient microstructure can be generated for the work material near the rivet hole surface due to high-gradient plastic deformation and friction. In this work, discontinuous dynamic recrystallization (dDRX) is found to be the major recrystallization mechanism of aluminum alloy 6111 undergoing FSBR. A cellular automaton (CA) model is developed for the first time to simulate the evolution of microstructure of workpiece material during the dynamic FSBR process by incorporating main microstructure evolution mechanisms, including dislocation dynamics during severe plastic deformation, dynamic recovery, dDRX, and subsequent grain growth. Complex thermomechanical loading conditions during FSBR are obtained using a mesh-free Lagrangian particle-based smooth particle hydrodynamics (SPH) method, and are applied in the CA model to pred...

In this study, an analytical model for the stability of turning and boring processes is proposed. The proposed model is a step ahead from the previous studies as it includes the dynamics of the system in a multi-dimensional form, uses the true process geometry and models the insert nose radius in a precise manner. Simulations are conducted in order to compare the results with the traditional oriented transfer function stability model, and to show the effects of the insert nose radius on the stability limit. It is shown that very high errors in stability, which limit predictions can be caused when the true process geometry is not considered in the calculations. The proposed stability model predictions are compared with experimental results and an acceptable agreement is observed.

The design of joints between parts is one of the most critical issues in the design of sheet metal assemblies. This paper presents a new part-to-part joint design evaluation index developed for dimensional control of sheet metal assemblies. The proposed index provides a new analytical tool to address the dimensional capabilities of an assembly process in the early product design stage. It covers the three basic types of joints, which encompass the whole domain of joints used in sheet metal assembly. The part-to-part interactions for each type of joint are studied, and an analytical model is provided. Two evaluation indices, (1) product joint design evaluation and (2) critical part determination, are developed. The developed methodology is demonstrated using two industrial design examples of sport-utility automotive bodies.

A statistical analysis of hole quality in drilling was performed. Using standard twist drills, holes were drilled dry in hot rolled steel. The effects of feed and speed on the hole quality features of oversize, out-of-roundness, location error, angularity error, and taper were examined using a full factorial analysis of variance. The effects of workpiece surface condition, geometrical variation among drills, and drill wear were qualitatively observed. The results showed that feed and speed have a relatively small effect on the measured hole quality features. With the exception of hole location error, the hole quality was not predictably or significantly affected by the cutting conditions. Although these results were not expected, they have the important positive implication that production rates may be increased without sacrificing hole quality. The drilling feeds and speeds would be constrained by factors other than hole quality, such as drill wear, drill breakage, or force, torque...