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 Counterbalance System: Setup and Troubleshooting

admin

The counterbalance system on a servo press uses pneumatic pressure to offset the weight of the slide and upper die. Correct counterbalance pressure is essential for servo motor performance and slide control accuracy.

## Purpose of Counterbalance

Without counterbalance, the servo motor must support the full weight of the slide (typically 500-5000 kg) during the upstroke. This:
- Increases motor current and heat
- Reduces available torque for acceleration
- Causes asymmetric load on the drive (motor works hard on upstroke, regenerates on downstroke)

With correct counterbalance, the pneumatic cylinder supports the slide weight, and the servo motor only handles acceleration/deceleration forces.

## Setting Counterbalance Pressure

The correct counterbalance pressure depends on slide weight plus upper die weight.

**Formula:**
```
P = (W_slide + W_die) ? g / A_cylinder
```
Where P = pressure (Pa), W = weight (kg), g = 9.81 m/s?, A = cylinder area (m?)

**Practical method:**
1. Install die and set slide to mid-stroke position
2. Adjust counterbalance pressure until motor current is equal on upstroke and downstroke (monitor on drive display)
3. Fine-tune: reduce pressure slightly until downstroke current is 5-10% higher than upstroke (slight over-balance is acceptable)

**Typical pressure range:** 0.3-0.8 MPa depending on press size

## Troubleshooting Counterbalance Issues

**Slide drops when brake releases:**
- Counterbalance pressure too low
- Counterbalance cylinder seal worn —check for air leakage at cylinder

**Motor overheating on upstroke:**
- Counterbalance pressure too low —motor carrying too much slide weight
- Check pressure gauge at cylinder (not just at regulator —pressure drop in lines)

**Slide bounces at TDC:**
- Counterbalance pressure too high —pneumatic force exceeds slide weight
- Reduce pressure by 0.05 MPa increments until bounce stops

**Pressure drops during production:**
- Air supply insufficient —check compressor capacity
- Counterbalance cylinder seal leaking —listen for air leaks

raj_maintenance

Counterbalance leaks are sneaky. We had a slow leak that dropped pressure 10% over 3 weeks. The motor was working harder on every return stroke and we were getting intermittent overcurrent faults that seemed random. Took us a week to connect the dots. Now we log counterbalance pressure daily on a chart at the press.

mike_chen_eng

Counterbalance tip for multi-die shops: create a counterbalance pressure table for each die set and laminate it to the die cart. When the die is loaded, the operator sets the correct pressure before the first stroke. Eliminates the guesswork and prevents the common mistake of running a heavy die with light-die counterbalance settings.

raj_maintenance

Counterbalance troubleshooting shortcut: if you suspect a leak but cannot find it, spray soapy water on all fittings and cylinder seals while the system is pressurized. Bubbles show you exactly where the leak is. We found a pinhole leak in a fitting that was losing 2 PSI per day. Invisible to the eye but the soapy water test caught it in 30 seconds.