The TL2 completes the commanded R90. spindle rotation, leaves the X distance-to-go near 1.000 mm, then advances only a few micrometres over several minutes. The key diagnostic is that manually displacing the chuck makes the displayed distance-to-go decrease and eventually lets the program finish. Follow the packet: trace the command from the G05 block through spindle position feedback, motion interpolation, and the X-axis command.
Where does the G05 motion stop?
The failing block is G05 R90. U-1. F200;. Its rotational component executes, but the requested X component does not complete normally. Separate the displayed command state from physical movement before changing parameters.
| Path stage | Reading or observation | Meaning |
|---|---|---|
| Program interpreter | The control enters the G05 block and shows 1.000 mm X distance-to-go |
The U-1. request was accepted rather than skipped |
| Spindle motion | The chuck rotates through the requested 90 degrees | The R90. portion and M19 hardware can produce indexed motion |
| X command | X distance-to-go changes from about 1.000 to 0.997 mm and then decreases extremely slowly | The block remains active; determine whether the interpolator is withholding X motion or the X servo cannot follow it |
| Spindle feedback | Moving the chuck by hand reduces X distance-to-go | Block progress is responding to spindle displacement or spindle-position feedback, so a standalone X obstruction is not the first branch to pursue |
Do not treat the completed 90-degree rotation as proof that spindle positioning is healthy. An orientation can reach its nominal target while weak position holding, feedback lag, or incorrect motion-loop behavior prevents the combined block from satisfying its completion criteria.
Is the spindle feedback path mechanically stable?
Layer one first. Lock out the machine before inspecting the encoder drive, couplings, connectors, and spindle transmission. The encoder belt was reported as not loose, but visual tightness alone does not verify correct tension, tooth engagement, pulley security, or encoder-shaft coupling.
- Mark the encoder pulley, driven pulley, and shaft positions with removable witness marks.
- Rotate the spindle slowly by an approved service method and inspect for belt tooth jump, pulley slip, backlash, or delayed encoder motion.
- Check encoder and motor-feedback connectors for incomplete seating, contamination, damaged pins, and cable movement near strain-relief points.
- Obtain the specified encoder-belt tension from the service documentation for the installed TL2 and M19 hardware. No tension value is established here; do not substitute a generic belt value.
A chuck that can be displaced several degrees, followed by roughly half a second before the control reacts, directs attention to spindle position-loop response. The deciding readings are actual spindle position, commanded spindle position, and position error during orientation and while a small external load is applied using the manufacturer-approved test method.
Does the control track spindle displacement correctly?
Run M19 by itself with tooling clear. Record commanded position, actual position, and position error from the control diagnostics. Apply no cutting load during this test.
| Result | Diagnosis | Next check |
|---|---|---|
| Actual position follows commanded position promptly and returns without sustained error | The basic orientation loop is functioning | Proceed to X-axis command monitoring during G05
|
| Actual position changes late when the chuck moves | Inspect encoder transmission, feedback wiring, and diagnostic update behavior | Correct the physical feedback path before retesting interpolation |
| Feedback changes promptly, but the spindle remains soft or fails to recover position | The spindle position loop or drive commissioning requires service evaluation | Record position error and drive status for Haas service |
| Displayed position is stable while witness marks show mechanical movement | Feedback is not representing chuck motion correctly | Inspect the encoder coupling, belt, pulley attachment, and feedback channel |
Do not tune an undocumented gain or tension setting to mask the symptom. Capture the diagnostic values first. A mechanical feedback fault and an incorrectly commissioned position loop can produce similar behavior at the operator display but require different corrections.
Is X commanded, or is the interpolator waiting?
Display X commanded position, X actual position, X distance-to-go, spindle commanded position, and spindle actual position together while executing the minimal block at reduced machine motion settings approved for testing.
| X command | X actual | Spindle error | Branch |
|---|---|---|---|
| Does not advance | Does not advance | Persists or changes with chuck displacement | The interpolator is waiting on the spindle-position path; investigate feedback, position-loop completion, option commissioning, or software behavior |
| Advances normally | Does not follow | Remains controlled | Troubleshoot the X servo, drive status, mechanical load, and following error |
| Advances only when the chuck is displaced | Follows the small command | Changes at the same time | The X axis is responding, but its command progression is coupled to unresolved spindle motion |
| Command and actual both reach the target | Reaches target | Returns to the normal settled state | The fault is intermittent; repeat while recording diagnostics and program state |
The reported response to forced chuck movement fits the first or third branch. It does not justify replacing an X-axis component without seeing an X command that the physical axis fails to follow.
Does the minimal program reproduce the failure?
Use the shortest program that retains the failure. The reported metric sequence was:
T40;
G54;
M19;
G98;
G00 X40. Z0.5;
G01 Z-1. F200;
G05 R90. U-1. F200;
G00 Z5.;
M30;For diagnostic execution, remove the cutting engagement and establish clearance while preserving M19, G98, and the exact G05 R90. U-1. F200 block. First run G05 R90. F200; then add U-1.. This A/B test separates basic indexed rotation from the combined spindle/X path.
The same behavior occurred with different angles and with X substituted for U. That makes incremental-versus-absolute X syntax a weaker diagnosis. Software L0905E and the installed M19 option remain part of the configuration record. If the manual example also stalls after removing the inapplicable M133 P1500, give Haas support the unmodified example reference, every deliberate edit, and the diagnostic trace; changing a manual example can change its required machine state.
What procedure fixes the resolving branch?
- Verify the encoder belt, pulleys, coupling, connectors, and cable path against the TL2 service procedure. Correct any slip, damaged engagement, or connection fault.
- Run
M19and confirm that commanded spindle position, actual position, and position error respond promptly and settle while the spindle holds position. - Run the cleared
G05 R90. F200test and record spindle diagnostics. - Add
U-1.and record X command, X actual position, X distance-to-go, spindle command, and spindle actual position from block entry to completion. - If the spindle settles but the X command remains withheld, have Haas verify M19-option commissioning and
L0905Ebehavior against the exact minimal program. Do not alter undocumented control parameters. - After mechanical, commissioning, or software correction, rerun the cleared program. Confirm a 90-degree rotation, the full commanded 1.000 mm X increment in the requested direction, normal distance-to-go decay, execution of
G00 Z5., and arrival atM30without touching the chuck.
FAQ
Can I diagnose this TL2 G05 hang as an X-axis fault?
Not from X distance-to-go alone. Compare X commanded and actual positions; if the command advances only when spindle position changes, troubleshoot the spindle feedback and interpolation path first.
Does a successful M19 prove the spindle loop is correct?
No. Record commanded position, actual position, and position error after M19; the spindle must reach, hold, and recover its orientation promptly.
Can I set the encoder-belt tension by feel?
No. Use the service value for the installed TL2 and M19 hardware, and inspect pulley attachment, tooth engagement, and coupling slip as well as belt tension.
Does zero distance-to-go prove the G05 repair worked?
No. Verify that the chuck rotates 90 degrees, X physically completes the commanded 1.000 mm increment, G00 Z5. executes, and the program reaches M30 without external spindle movement.