6411

In NCK menu path: Diagnosis > Tool Management > Tool Monitoring, verify MD20170 = 1 (monitoring enabled) and MD20174 = 1 (wear monitoring active) for the tool offset.

Check the current wear value stored in the D offset register against the wear limit in the tool table. Access via: Machining > Tool Table > select tool > review D offset and associated wear counter value.

Adjust MD20175 (prewarning limit percentage, typically 80%) downward if earlier notification is desired, or plan tool change per maintenance schedule. After tool replacement, reset wear counters via TOOL OFFSET DELETE command or PLC function FC2 (tool offset reset).

Do not disable MD20170 without supervisor approval; this disables critical tool protection.

Confirm the alarm clears after tool change or offset reset by verifying no D offset is in prewarning state via Diagnosis > Tool Monitoring display.

Verify monitoring type via Diagnosis > Tool Management: check MD20174 value (3 = time-based in minutes, 4 = quantity-based). If value is 3 or 4, time/quantity monitoring is active.

Review the tool life configuration in the Tool Table (Machining > Tool Table > select tool D offset). Check the 'Life Time' field (for time-based) or 'Life Quantity' field (for quantity-based) and compare against current counter value displayed in parentheses.

If prewarning was premature, adjust MD20175 upward (default 80%) or increase MD20176 (tool life value). If tool is genuinely approaching end-of-life, schedule replacement and reset counters via Tool Table dialog or PLC function.

Time-based monitoring continues even during spindle dwell; verify actual productive run time against life limit.

Clear the prewarning by resetting the tool life counter: select tool in Tool Table, set Life Counter to 0, and confirm alarm 6411 no longer appears in active alarms.

Check if additive offset mode is active: Diagnosis > Tool Management > verify MD20177 = 1 (additive offset enabled). If enabled, the D offset register accumulates DL (delta length) values from adaptive machining or automatic tool length compensation routines.

Review the current D offset value and compare to the base offset in the Tool Table. Calculate accumulated additive corrections: (current D offset - base D offset). Check this value against MD20178 (additive offset limit, typically ±2.0 mm).

If additive offset has accumulated near the limit, reset the D offset to its original base value via Tool Table edit dialog. Then adjust the base offset (D number in tool table) by the accumulated correction amount to restore tool geometry without losing the correction.

Always verify tool geometry is correct before resuming production; incorrect offset reset can cause tool crashes or scrap parts.