A used Amada HFB 170-40 press brake booted and began initialization, but one ram moved without backgauge motion and the control faulted. The reported fault path involved missing travel feedback from both Y-axis linear scales. Replacing both scales, replacing six heat-damaged relays, and recalibrating the machine restored operation.
Initialization mechanism and failure signature
According to the reported Amada service guidance, initialization begins with slight downward Y-axis movement so the control can detect ram position. Backgauge initialization follows only after the control detects that movement. If a scale supplies no movement feedback, the associated cylinder can continue moving while the expected sequence stalls.
| Observed condition | Supported interpretation |
|---|---|
| Machine boots and starts initialization | The fault occurs after startup, during motion initialization. |
| One ram closes, but the backgauge does not move | The control may be waiting for valid Y-axis movement feedback. |
| Fault changes sides when Y1 and Y2 scale connections are exchanged | The problem follows the scale or its signal path rather than remaining with one axis channel. |
| Origin pulse is present but travel readings are absent | An origin indication alone does not prove that the scale reports motion. |
Isolate the defective linear-scale channel
- Record which ram moves and which axis lacks a position change during initialization.
- Identify the Y1 and Y2 linear-scale connections.
- Exchange the Y1 and Y2 scale connections, using the same controlled initialization test.
- Observe whether the missing-reading symptom changes from one axis to the other. In the reported case, the problem switched sides, supporting a scale-side fault while indicating that the board and relay channels could respond to the exchanged signals.
- Return the wiring to its intended configuration before repair or calibration.
This swap is an isolation test, not proof that every board or relay function is healthy. It shows whether the observed fault follows the connected feedback device. Cleaning the glass and reader did not repair the first scale in this case, although another reported machine recovered after scale cleaning; therefore, inspect and clean only as a diagnostic attempt, then verify actual travel feedback.
Resolve the MAX DELTA AXIS EXCEEDED fault
After replacing the first scale, initialization completed, but manual bending produced MAX DELTA AXIS EXCEEDED. Y1 stopped about 3 inches into downward travel while Y2 continued until the closing pedal was released. This behavior indicates that the two axes were no longer tracking within the control's accepted relationship, but the evidence does not provide the permitted delta, calibration values, or adjustment parameters.
The remaining scale supplied the z pulse used for origin but supplied no travel readings. This explains why an axis could appear to establish origin and then fail during continued motion. Replace or repair the feedback device only after confirming that origin and continuous travel feedback are separate parts of the diagnosis.
Inspect relays and recalibrate after feedback repair
Six relays were found slightly burned but still functional. They were replaced during the final repair. Because swapping the scale connections had already moved the symptom between axes, the relays were not the sole explanation for the original side-specific failure; however, visible heat damage justified replacement.
Both linear scales were ultimately replaced, followed by complete recalibration. The available evidence does not identify calibration parameters or the required service sequence, so use the applicable Amada service procedure or an Amada technician rather than inventing offsets. A jump when an axis begins opening after scale removal and reinstallation is also a reason to verify calibration, but the evidence does not establish a specific adjustment as the cure.
Verify the completed repair
- Initialize the machine and confirm that both Y axes produce movement feedback before backgauge initialization begins.
- Confirm that the backgauge completes its expected initialization movement.
- Run controlled manual ram motion and verify that Y1 and Y2 continue moving together without
MAX DELTA AXIS EXCEEDED. - Check that neither axis jumps when opening begins or when the opening pedal commands full opening.
- Complete a controlled bend only after initialization, synchronized travel, and recalibration checks pass.
In the documented repair, replacing both linear scales, replacing the six damaged relays, and recalibrating restored normal machine operation.
FAQ
Why does an Amada HFB 170-40 move one ram but not initialize the backgauge?
The control may not be receiving Y-axis movement feedback during the initial downward motion. Exchange the Y1 and Y2 scale connections as an isolation test and check whether the fault changes sides.
What causes MAX DELTA AXIS EXCEEDED on an Amada HFB?
In this case, Y1 stopped about 3 inches into downward travel while Y2 continued because the remaining scale provided an origin pulse but no travel readings. Replacing that scale and recalibrating formed part of the successful repair.
Does cleaning an Amada HFB linear scale fix missing position feedback?
Cleaning did not restore the first failed scale in the documented case, although another machine reportedly recovered after cleaning. Verify both origin and continuous travel readings afterward; replace or repair the scale if travel feedback remains absent.
