Rigid mode can be selected either by commanding M29 (which is the number stored in parameter 5210 in the range 0 to 255. If 0 or 29 is stored, M29 selects the rigid mode) in or before the tapping block, or by setting parameter 5200#0 to 1, which would always use rigid mode for G84/G88, as on a milling machine
Peck tapping
Continuous tapping operation up to the bottom of the hole does not clear the chips until final retraction. While this creates no problem for shallow holes, the tapped hole and/or the tap itself may get damaged due to chip clogging, if the hole is too deep (actually, when the depth to diameter ratio is large). In such cases, peck tapping solves the problem, which works in a way similar to hand tapping we tap up to some distance, then retract a bit by rotating the tap in the opposite direction, then tap further, retract again, and continue in the same manner till the bottom of the hole is reached. A similar thing can be done with G84/G88 also, in both rigid and non-rigid modes, by specifying a Q-word for peck length, as in a peck drilling cycle, provided parameter 5104#6 is set to 1. When this parameter is set to 0, a Q-word in G84/G88 becomes invalid. When set to 1, and pecking is not desired, do not specify a Q-word or specify Q0.
As in case of peck drilling, two types of retractions after every peck is possible: partial retraction (high-speed pecking) and full retraction up to the R-point (standard pecking, suitable for deep holes), selectable through parameter 5200#5 when set to 0 and 1, respectively. The retraction/clearance distance d (as defined in Figs. 2 and 3) during pecks is specified in parameter 5213.
