All metals have unique advantages and disadvantages in terms of their mechanical properties. Advantages such as flexibility are needed for construction and for the manufacture of sophisticated products. Some industries have improved the mechanical properties of metals by welding dissimilar ones together, such as aluminum alloy (AA) to stainless steel (SS) to reduce vehicle weights in order to improve fuel consumption. However, little research has been conducted on using micro resistance spot welding (mRSW) to join SS and Al by inserting a zinc (Zn) sheet between them as an interlayer. In this study, the mechanical properties of the weldment are tested using a shear test and Vickers micro hardness test. The results are compared using welding times of 6, 8 and 10 cycle times (CTs) and welding currents of 5 and 8 kA during the mRSW process. It is found that the SS, Zn and AA sheets could be joined with mRSW using an 8 kAA welding current and a 6 CT welding time. The micro hardness in the AA-Zn dissimilar joint increased relative to SS-Zn. Using a Zn sheet also improved displacement in the tensile shear test; however, it also increased the hardness of the diffusion zone.

This paper presents a simple analytical approach to define cut geometry of multi-pass rough milling during a free-form surface milling. The shape of in-process workpiece surface was identified using the coordinate of corner points that are found in every step of stair-surface. In every instantaneous tool location, the workpiece sections that have possibility intersecting with the cutting edge were identified based on the coordinate of cutter location point. The algorithm was developed for machining using indexable flat end-mill by considering the effect of helix angle to the cut geometry. The proposed method was successfully used to determine the length of cut and generate the shape of cuts. The implementation test also demonstrated that helix angle tends to produce larger cut.The validation of the accuracy was carried out by comparing the length of cut measured using CAD software with those generated by the proposed approach. The results showed that the differences were very small or less than 0.4%. Therefore, it can be taken into conclusion that the method was accurate. The comparison test on computational time was conducted. ABS took only 1.63 second for calculating cut geometry during one tool pass, while Z-mapping method spent 23.21 second. This result proved that ABS is computationally more efficient.

One of the characteristics of five-axis milling is the tool can be oriented in any direction. It makes the tool orientation could be changed continuously during a free-form machining process. Consequently, the work to predict Cutter Workpiece Engagement (CWE) become more challenging. The existence of tool inclination angle and screw angle influence the profile of cut geometry. In this paper, an improved method to define the lower engagement point (LE-point) is presented. The algorithm was developed by taken into consideration the existence of inclination angle and screw angle. The extended method to calculate grazing point in swept envelope development was utilized to define LE-point. The developed model was successfully implemented to generate CWE data with various combination of tool orientation angle. From the test it was found that inclination angle gives significant effect to the location of LE-point.