Alarm 1420 fires when the Haas probing calibration routine cannot achieve repeatable measurements within tolerance or fails to store validated calibration offsets in macro variables 591-599. The NGC control invalidates existing calibration data and requires successful recalibration before probing cycles can resume.
HaasProbingIntermediate20-60 minutes
1420
Haas Alarm 1420 - Probing Calibration
Probing Calibration
This alarm indicates the wireless probing system calibration has failed or expired and the control will not allow probing cycles to execute. The MOCON stores probe calibration data including stylus effective diameter, trigger force, and frequency pairing between probe and receiver module. Without valid calibration data the control cannot compensate for probe deflection and stylus geometry resulting in inaccurate measurement.
Root Cause Summary
Alarm 1420 fires when the Haas probing calibration routine cannot achieve repeatable measurements within tolerance or fails to store validated calibration offsets in macro variables 591-599. The NGC control invalidates existing calibration data and requires successful recalibration before probing cycles can resume.
Safety
Disable spindle and set feedrate override to 10-25% when manually jogging probe stylus into contact surfaces during diagnostic testing—full speed contact can damage probe or break stylus
Verify probe is properly seated in spindle taper and drawbar is engaged before any movement—unsecured probe can fall during Z-axis motion causing injury or machine damage
Causes and Fixes
1
Inspect Probe Tip Condition
Remove probe from spindle and examine ruby tip under magnification for chips, wear, contamination, or loose mounting. Check for coolant residue or debris buildup.
Use a 10x magnifier to inspect for microscopic damage that affects repeatability
2
Clean Probe Assembly
Clean probe tip with isopropyl alcohol and lint-free cloth. Ensure probe body and electrical contacts are clean and dry before reinstallation.
Never use compressed air directly on probe tip as it may damage the ruby ball
3
Verify Probe Installation
Reinstall probe ensuring proper seating in spindle taper. Check that probe cable is properly routed and not binding during spindle rotation.
Manually trigger probe while installed to verify consistent electrical contact
4
Re-run Calibration Routine
Execute probing calibration from PROBING menu. Monitor repeatability values displayed during calibration process.
Allow 15-20 minutes warm-up time before calibration for thermal stability
1
Verify Ring Installation
Check that calibration ring is properly clamped and indicated to within 0.0002" TIR. Ensure ring is clean and free of nicks or damage.
Use DTI to verify ring runout before starting calibration routine
2
Confirm Ring Dimensions
Verify calibration ring diameter matches value entered in macro variable 590. Measure with calibrated micrometers if uncertain.
Incorrect ring diameter entry will cause calibration failure and invalid offset calculations
3
Check Work Coordinate System
Ensure G54 work offset is properly set with ring center at approximate X0 Y0 position. Verify Z-height allows adequate probe travel.
Set Z-height so probe tip is 0.1" above ring surface when at G54 Z0
4
Execute Calibration Sequence
Run calibration from PROBING menu, monitoring for consistent trigger points around ring circumference.
Watch for any hesitation or irregular movement during probing sequence
1
Allow Thermal Stabilization
Run spindle at moderate RPM (1000-2000) for 15-20 minutes to achieve thermal equilibrium before attempting calibration.
Check ambient temperature stability - avoid calibration during HVAC cycling
2
Check Machine Warm-up Status
Verify machine has completed normal warm-up cycle. Check for any recent power-on or extended idle periods.
Calibrating on cold machine will result in invalid offsets as thermal growth occurs
3
Monitor Environmental Conditions
Ensure stable shop temperature and no direct airflow on machine during calibration. Close machine doors during process.
Ideal calibration temperature is within 2°F of normal operating temperature
4
Retry Calibration After Stabilization
Execute calibration routine once thermal stability is achieved. Monitor for improved repeatability values.
Successful calibration typically shows repeatability within 0.0001" on Haas systems
1
Clear Existing Calibration Data
Access SETTING 31 and clear macro variables 591-599. Verify macro variable 590 contains correct calibration ring diameter.
Write down existing values before clearing in case restoration is needed
2
Check Probing Parameters
Verify parameters 6180-6189 contain appropriate probing settings for feed rates, retract distances, and tolerance values.
Incorrect parameter values can cause calibration routine to fail or produce invalid results
3
Reset Probing System
Power cycle control or perform probing system reset from PROBING menu if available on your NGC version.
Some NGC versions have PROBE RESET function in diagnostics menu
4
Re-execute Calibration
Run complete calibration sequence with cleared variables. Monitor macro variables 591-599 for proper population during calibration.
Variables should populate sequentially as calibration progresses through measurement points
1
Check Spindle Condition
Manually rotate spindle and feel for roughness, play, or binding. Listen for unusual bearing noise during low-speed rotation.
Do not attempt spindle repairs - contact Haas service if spindle issues are suspected
2
Verify Axis Backlash
Use DTI to check X and Y axis backlash at calibration position. Excessive backlash will cause probe positioning errors.
Backlash should typically be less than 0.0002" on properly maintained Haas machines
3
Check Gib Adjustment
Verify axis gibs are properly adjusted per Haas specifications. Look for signs of excessive wear or improper lubrication.
Loose gibs often cause intermittent positioning errors that affect probe repeatability
4
Document Findings
Record any mechanical issues found and contact Haas service for guidance on repairs before attempting further calibration.
Continuing to use machine with mechanical issues may cause additional damage
DIY Feasiblehigh confidence
Call a technician if:
·Spindle mechanical issues detected
·Repeated calibration failures after cleaning and setup verification
·Macro variable or parameter corruption persists
Prevention
Maintain clean probe tips and calibration rings
Allow proper thermal stabilization before calibration
Perform regular calibration ring inspection and cleaning
Monitor macro variables 591-599 for corruption during routine maintenance
Common Mistakes
Attempting calibration on cold machine
Using contaminated or damaged calibration ring
Incorrect calibration ring diameter in macro variable 590
Rushing calibration process without proper setup verification
