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 Slide Parallelism Error: Diagnosis and Correction Procedure

admin

A slide parallelism error on a servo press causes uneven die loading, accelerated tooling wear, and part quality problems. Here is how to diagnose and correct it.

## Symptoms

- Uneven wear on die components (one side wears faster)
- Part dimensions vary across the width of the part
- Unusual noise or vibration during forming
- Tonnage monitor shows asymmetric loading
- Gib wear is uneven between left and right sides

## Measurement Procedure

You need a precision level (0.02mm/m resolution or better) and a dial indicator with magnetic base.

1. Clean the slide face and bolster face thoroughly
2. Place the precision level on the slide in the left-right direction. Record the reading.
3. Move the level to the front-back direction. Record the reading.
4. Jog the slide to 50% of stroke and repeat measurements.
5. Jog to bottom of stroke and repeat.

Acceptable parallelism: 0.02mm per 300mm in any direction.

## Common Causes

### Gib Wear (Most Common)
Uneven gib wear causes the slide to tilt as it travels. Check gib clearance at top, middle, and bottom of travel on both sides. If clearance varies by more than 0.03mm between sides, the gibs need adjustment or replacement.

### Eccentric Bearing Wear
If the main eccentric bearing is worn unevenly, the slide will tilt under load. This shows up as parallelism error that is worse under load than at no-load. Requires bearing inspection and possibly replacement.

### Connecting Rod Adjustment
On presses with adjustable connecting rods, if the left and right rods are set to different lengths, the slide will be non-parallel. Check and equalize the rod lengths.

### Crashed Die
A die crash can permanently deform the slide or bolster. If parallelism error appeared suddenly after a crash, inspect for deformation.

## Correction Procedure

1. Adjust gibs to equalize clearance on both sides
2. Re-measure parallelism
3. If still out of spec, check connecting rod lengths
4. If still out of spec after rod adjustment, the eccentric bearings need inspection
5. After correction, run 100 strokes and re-measure to verify stability

raj_maintenance

The four-corner measurement method described here is correct. One addition: measure at multiple slide positions (TDC, mid-stroke, BDC) because parallelism can change through the stroke if the gibs are worn unevenly. If it's only out at BDC, the gibs are the problem. If it's out everywhere, the frame may be twisted.

dave_toolmaker

From a die maker's view: if parallelism is off by more than 0.03mm, don't try to compensate in the die. Fix the press first. I've seen shops shim dies to compensate for press parallelism errors and it works until they move the die to a different press. Then nothing fits.