What is a servo press?

A servo press uses servo motors for precise force and position control during forming operations.

How do I calculate servo press tonnage?

Use our free tonnage calculator at servopress.club/tonnage-calculator.html

Servo Press Overtravel Alarm: Causes and Recovery Procedure

admin

An overtravel alarm occurs when the slide moves beyond the programmed software travel limit. On a servo press, this is a critical safety alarm that stops the press immediately.

## Why Overtravel Alarms Occur

**Software limit exceeded:**
- Slide height set incorrectly —die shut height taller than expected
- Motion profile programmed with BDC position below software limit
- Operator error during manual jog mode

**Hardware limit switch activated:**
- Physical overtravel switch triggered (backup to software limit)
- Switch wiring fault causing false activation
- Switch target gap out of specification

**Position reference lost:**
- After power loss, press homes to wrong position
- Encoder fault causing position jump

## Recovery Procedure

**Step 1: Do not panic-jog**
After an overtravel alarm, the press may be at or near a mechanical hard stop. Jogging in the wrong direction can cause damage.

**Step 2: Identify direction of overtravel**
Check the position display. If position shows a value beyond the software limit (e.g., limit is -300mm, position shows -305mm), the slide has gone too far down.

**Step 3: Enable overtravel recovery mode**
Most presses have an overtravel recovery function:
- Fanuc: hold OT RELEASE button while jogging in the recovery direction
- Siemens: set parameter p2551 (software limit bypass) temporarily
- Yaskawa: use SigmaWin+ to temporarily disable software limits

**Step 4: Jog to safe position**
Jog slide slowly in the direction away from the overtravel (upward if bottom overtravel). Move until position is within normal range.

**Step 5: Investigate root cause**
Before resuming production, determine why overtravel occurred. Check:
- Slide height setting vs die shut height
- Motion profile BDC position
- Home position accuracy

## Prevention

Set software limits with 5-10mm margin beyond maximum die shut height. Never set limits at the mechanical hard stop.

raj_maintenance

We had an overtravel alarm last year that turned out to be a failing proximity sensor on the overtravel limit switch. The sensor was reading intermittently, so the press would trip at random points in the stroke. Replaced the sensor for $45 and the problem was gone. Before you dig into the drive parameters, check the physical limit switches first.

mike_chen_eng

On overtravel recovery: one thing to add —after jogging out of overtravel, always re-run the homing cycle before resuming production. We had a case where the operator jogged out manually and resumed without re-homing. The position reference was off by 0.8mm, which caused a die crash on the next production run.

jim_applications

Overtravel recovery requires patience. After the alarm triggers, do not attempt to jog the press until you understand why it overtravel occurred. Common causes: incorrect motion profile loaded for the current die, counterbalance failure allowing the slide to drop, or a drive fault during the stroke that caused uncontrolled motion. Fix the root cause before clearing the alarm and resuming.