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

How we measured and reduced power consumption

jason_cnc

We instrumented our servo press line with power meters for 3 months. Here's what we found and the changes we made to cut consumption.

**Why Energy Matters
**
A 200T servo press consumes 30-80 kWh per shift depending on application. At $0.10/kWh, that is $3-8 per shift, or $750-2000 per year per press. For a plant with 20 presses, energy optimization is worth pursuing.

**How Servo Presses Use Energy
**
**Forming stroke:** Peak power draw, typically 3-10x rated motor power for 50-200ms.

**Return stroke:** Motor acts as generator, returning energy to DC bus. This energy is either:
- Returned to grid (regenerative drive): most efficient
- Stored in capacitors/batteries: good efficiency
- Dissipated in braking resistor: wasteful

**Idle:** Motor holds position, drawing 5-15% of rated power.

**Measuring Energy Consumption
**
Install a power meter on the press main power supply. Log kWh per shift. Most modern servo drives also report energy consumption via fieldbus.

Key metrics:
- kWh per 1000 strokes
- Peak kW demand (affects utility demand charges)
- Regenerated energy percentage

**Reduction Strategies**

**Enable regenerative braking:** If your drive has a regenerative unit, ensure it is enabled. Can reduce energy consumption by 20-30%.

**Optimize motion profile:** Reduce unnecessary acceleration. A smoother profile uses less energy than aggressive acceleration/deceleration.

**Reduce idle power:** Program the press to reduce motor holding torque during extended idle periods.

**Right-size the motor:** An oversized motor runs at low efficiency. Check motor loading — if average torque is below 40% of rated, consider a smaller motor.
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\n**Edit:** a few people asked about the power meters we used. They're Fluke 1760 units, not cheap but worth it for a proper study.

mchen_servo

On energy consumption — we installed power meters on all 12 of our servo presses last year. The variation between presses doing similar work was surprising: up to 35% difference (yeah, we were surprised too). The main factor was whether regenerative braking was enabled. Three presses had it disabled (previous maintenance had turned it off during a fault). Enabling it saved about $4,000/year per press.

toolndye_dave

The regenerative braking point is worth expanding on. On our Aida DSF-N2 line, we added a regen resistor bank initially, then switched to a regen unit that feeds back to the plant bus. The payback was about 14 months at our energy rates (industrial tariff, ~$0.09/kWh). The key metric to track is the deceleration energy per stroke — on a 200-ton press running at 40 SPM, we were recovering about 1.8 kWh per hour of production.

For measurement: clamp meters on the DC bus give you the most accurate picture. The drive's built-in energy meter is convenient but tends to undercount regen by 10-15% in my experience.

raj_pm

One thing that surprised us when we started metering: idle draw is a bigger deal than most people think. Our 300T Aida was pulling 3.8kW just sitting there between runs — cooling fans, control power, hydraulic unit for the counterbalance. Over a 2-shift day with maybe 40% actual press time, idle consumption was almost 30% of total energy.

Easiest win: we added a PLC routine that drops the press into standby after 5 minutes of no cycle command. Shuts off the cooling fans and puts the drive in sleep mode. Drops idle from 3.8kW to about 0.4kW. Saves us roughly $180/month on that one press alone. The catch is you need a 15-second wake-up before the first stroke, so the operator has to plan ahead a bit.

For the metering setup — don't bother with clamp meters for long-term monitoring. We use Schneider PM5110 power meters hardwired on each press feed. About $350 each, logs to Modbus, and our SCADA picks it up. The per-stroke energy data is what really helps with optimization — you can see exactly which motion profile changes actually save energy vs just shifting it around in the cycle.