TL;DR
Ram positioning errors usually trace to dirty or damaged linear encoders or worn hydraulic seals. Clean the encoder strip and check hydraulic pressure before adjusting parameters.
What you might see
- controller shows positioning fault on Y1 or Y2 axis
- bend angle inconsistency part to part
- ram stops mid-stroke
- hydraulic pressure alarm active
Likely causes
Linear encoder strip contaminated with oil mist or metallic dust
Hydraulic pressure loss from worn cylinder seals or low fluid level
Y1/Y2 axis servo drive fault or encoder cable damage
Back-gauge or crowning calibration drift after tool change
Required tools
- Lint-free cloths and isopropyl alcohol
- Digital protractor (angle gauge)
- Hydraulic fluid per press nameplate specification
- Multimeter for encoder cable continuity check
- LOTO kit
Safety first
- The press ram can move without warning if hydraulic circuits are live. Always confirm zero pressure before reaching into the bend zone.
- Lock out the main disconnect before opening the encoder cover or hydraulic access panels.
- Never place hands or fingers in the die area during calibration test bends.
Procedure
- 1
Power down the press brake and lock out the main electrical disconnect.
Warning: The ram holds stored hydraulic pressure. Confirm pressure gauge reads zero before working near the cylinder. - 2
Open the encoder cover on each Y axis and inspect the linear encoder strip for oil film, scratches, or debris.
- 3
Wipe the encoder strip gently with a lint-free cloth and isopropyl alcohol. Do not use abrasive pads.
- 4
Inspect the encoder read head for physical damage or misalignment. Re-seat any loose read-head mounting screws.[1]
- 5
Check the hydraulic fluid level in the reservoir against the sight glass and top up with the grade specified on the press nameplate.
- 6
Start the machine, open the hydraulic pressure monitoring screen, and verify Y1 and Y2 circuit pressures match the machine specification.[1]
- 7
Run a test bend on a known-dimension sample and measure the angle with a digital protractor. If angle is out, re-run the angle calibration wizard from the Amada controller.
- 8
If the fault persists after encoder cleaning, swap the encoder cable to rule out cable damage before replacing the read head.
Sources
Amada Amada HG / HFE 3i Press Brake general technical documentation, Amada
Amada HG / HFE 3i press brake operator and maintenance documentation, general encoder and hydraulic inspection procedures (general)
More guides for Amada Amada HG / HFE 3i
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Back-gauge drift is usually a worn ball screw, loose timing belt, or lost home reference. Check belt tension and re-home the axis before bending production parts.
How to fix hydraulic oil overheating on an Amada HG / HFE 3i press brake
Oil overheating on a press brake is usually a clogged cooler or low fluid level. Check the oil cooler heat exchanger and top up fluid before resuming production.
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