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 Maintenance

admin

## What the Counterbalance Does

The pneumatic counterbalance supports the weight of the slide and upper die on the return stroke. Without it, the servo motor must lift the full slide weight, increasing motor size and energy consumption.

## Setting Counterbalance Pressure

Correct counterbalance pressure = slide weight + upper die weight, expressed as air pressure.

Formula: P = (W_slide + W_die) / A_cylinder

Where A_cylinder is the total piston area of all counterbalance cylinders.

Example: 200T press, slide weight 800kg, die weight 400kg, two cylinders each 200cm2:
P = (800+400) x 9.81 / (2 x 200 x 100) = 0.29 MPa = 2.9 bar

Most press manuals provide a table of counterbalance pressure vs. die weight.

## Signs of Wrong Counterbalance Pressure

**Too low:** Motor overload alarm on return stroke, A.74 or F07801 on return.

**Too high:** Press bounces at TDC, slide does not stop smoothly at top.

## Maintenance

- Check pressure daily (should be within 10% of set point)
- Check for air leaks at cylinder seals and fittings monthly
- Replace cylinder seals every 3-5 years or when leakage is detected
- Check accumulator pre-charge pressure annually (should be 60-70% of working pressure)

mike_chen_eng

On counterbalance pressure setup: the goal is to make the slide weightless at mid-stroke so the drive sees near-zero load moving upward. Practical check: jog the slide up and down at low speed and monitor drive current. If current is roughly equal in both directions, your counterbalance is dialed in.

Also: check counterbalance cylinder seals every 2 years or 5M strokes. A slow leak shifts your pressure setpoint gradually and you will not notice until drive overload faults start appearing.

jim_applications

The counterbalance pressure formula is simple: pressure = (slide weight + upper die weight) / cylinder area ? 0.9. The 0.9 factor is intentional —you want the counterbalance to support 90% of the weight, not 100%. At 100% the slide tends to float up and you lose BDC accuracy.