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 Home Position Lost: Safe Recovery Without Crashing the Die

admin

Losing the home position on a servo press is a serious situation. If you jog the press without knowing where the slide is, you can crash the die. Here is the safe recovery procedure.

## Why Home Position Gets Lost

Absolute encoder systems retain position through power cycles via a battery. Home position is lost when:
- Encoder battery dies
- Encoder is replaced
- Drive parameters are reset to factory defaults
- Encoder cable is disconnected with power off for more than 30 seconds
- Drive firmware update resets position data

## Step 1: Establish Slide Position Visually Before Jogging

1. Open the press guarding and visually locate the slide
2. Estimate the slide position relative to BDC
3. Check if there is a die in the press - if yes, do NOT jog until you know the exact position
4. If a die is in the press and the slide is near BDC, manually crank the press to TDC before proceeding

## Step 2: Set Temporary Safe Limits

Before running the homing routine:
1. Set the software upper limit to TDC position (typically 0mm)
2. Set the software lower limit to 10mm above BDC
3. This prevents the slide from traveling to BDC during homing

## Step 3: Run the Homing Routine

Different press brands have different homing procedures:

Aida/Komatsu (Yaskawa drive):
- Set parameter Pn816 (home position offset) to 0
- Execute home position return via the press HMI (usually under Maintenance > Homing)
- The press will move to the home switch at slow speed, then set position to 0

Schuler (Siemens drive):
- Use STARTER software to set r2521 (position actual value) to the known position
- Or use the press HMI homing function under Setup mode

Generic procedure:
1. Jog the slide to TDC at minimum speed (1-5mm/s)
2. At TDC, set the current position as the home position in the drive
3. Verify by jogging 10mm down and back - position should return to 0 at TDC

## Step 4: Verify Before Production

1. Run 3 complete strokes at 10% speed with no die
2. Check that BDC position matches the expected value
3. Install die and run 3 strokes at 10% speed
4. Verify die clearance at BDC with feeler gauge
5. Only then return to production speed

tom_pressops

This happened to me on a night shift. Scariest moment of my career —the slide was somewhere mid-stroke with a die in the press and I had no idea where exactly. Followed the manual jog procedure at 1mm/s with a dial indicator on the slide. Took 45 minutes but got it home safely. The key is patience. Do NOT rush this.

anna_controls

On Yaskawa drives, you can read the absolute encoder position even after home is lost —it's in monitor Un00D. The number won't mean anything until you correlate it with a known physical position, but it tells you approximately where the slide is. On Siemens, check r0063. This information should be posted at every press.