**4. Experiment**

For experiment purpose, we select three tool rotation speed (710 rpm, 960 rpm, and 1400 rpm) and welding speed ranges from 60 to 140 mm/min based on literature survey. In this investigation, there are three variable parameters selected (and performed experiments based on different combination), and the remaining parameters are kept constant. All nine experiments were carried out to find the suitable parameter combination that gives high tensile strength at the joint. The process parameters for the eight experiments are shown in **Table 4**.

 A conventional vertical milling machine was used to perform the experiments. Aluminum alloy plates were mounted on the machine work table with the help of a base plate, four clamps and nut screws that were tightened by spanner (shown in **Figures 1** and **2**). All experiments were carried out after setting the process parameter according to **Table 4**.


**Table 4.**  *Variable process parameter.* 

**Figure 1.**  *Base plate and plate set-up.* 

**Figure 2.**  *Welding of Al alloy 7075 T6.* 

The test specimen for tensile test was cut from the welded plates as per the ASTM E-8 standard for 6 mm plate thickness for aluminum alloy. Overall length of the test specimen is 100 mm.
