This is collection of methods to control weld power and temperature with unprecedented accuracy, precision and process robustness. These control techniques are implemented on the spindle axis only and run independently from weld path and forge axis motion. Power Control Command a constant power Power Ramps Command a power profile defined as a polynomial function of time Handoff from power control to robust temperature control (RTC) mode or to RTC profile mode when the user defined transition temperature is reached Basic Temperature control Uses standard PID cascade control algorithm as shown in Figure 1. Robust Temperature Control (RTC) This mode enables powerful regulator gains to be used when the measured value is close to the setpoint and less aggressive servo gains when the measured value is far from the setpoint. This results in dramatic improvements in process stability and disturbance rejection. RTC Ramp Ability to command a ramp in temperature Power Sinusoid Ability to command a sinusoid in power. This is helpful for system identification and modeling. Relay Tuning Executes relay tuning. This is helpful in system identification and PID gain tuning Modes 2, 4 and 5 are not reported in literature. The ability to produce power and temperature control ramps is something that has not been reported in literature. The ability to switch between servo and regulator gains has not been reported in literature. The ability to hand off from power ramps to temperature control has not been reported in literature. All of these features are useful for controlling friction stir welds. Especially during the plunge and initial traverse. This inventions includes Ladder Logic, Flow chart and Structured text version of control logic to implement control modes described above. Note: Methods were developed and reduced to practice in March of 2015 by Ken Ross. IN 2019 WoongJo Choi helped translate Ladder Logic to Structured Text and flow charts. I will work with IP/Commercialization to determine how to capture his contribution. He should be credited for translation of methods into structured text and flow charts