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## What Is Die Protection
Die protection monitors the press stroke and stops the press if an abnormal condition is detected — before the die is damaged. On a servo press, die protection is more effective than on mechanical presses because the press can stop faster.
## Types of Die Protection Sensors
**Tonnage monitoring:** Detects abnormal force. Catches double blanks, missing blanks, broken punches.
**Position sensors in die:** Detect material presence, part ejection, scrap removal. Typically inductive proximity sensors or fiber optic sensors.
**Cam switches:** Trigger at specific slide positions to check sensor states.
## Setting Up Position-Based Die Protection
1. Define check windows: the slide position range where each sensor should be in a specific state
2. Example: material presence sensor should be ON between 180mm and 10mm above BDC
3. If sensor is OFF during this window: stop press immediately
## Servo Press Stopping Distance
A servo press can stop in 5-15mm of slide travel (depending on speed and press size). A mechanical press needs 30-60mm. This means die protection is more effective on servo presses — less die damage when a fault is detected.
## Common Die Protection Faults
- Part not ejected: part sensor still ON after return stroke
- Scrap not cleared: scrap sensor still ON at start of next stroke
- Double blank: tonnage high limit exceeded
- Missing blank: tonnage low limit not reached
## Parameter Settings
Set stopping distance parameter to 10mm for most applications. For fragile dies, reduce to 5mm (requires slower forming speed).