| CPC B21J 5/066 (2013.01) [G05B 19/182 (2013.01); Y10T 29/53383 (2015.01)] | 16 Claims |

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1. A method for controlling a flow-hole and thread-forming process in which a fastener is driven through a workpiece with a rotation speed (N), a torque (M), and a feed force (F) over a penetration depth (Z), the method comprising:
a) measuring a process parameter (R(t)) of the flow-hole and thread-forming process;
b) determining a smoothed curve (R*(t)) of the process parameter (R(t));
c) determining a difference (D(t)) of the process parameter (R(t)) and its smoothed curve (R*(t)), D(t)=R(t)−R*(t); and
d) changing a process parameter of the flow-hole and thread-forming process based on the difference (D(t)),
wherein the process parameter (R(t)) is formed based on at least one of: the rotation speed (N), the torque (M), the feed force (F), and the penetration depth (Z).
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