Preparation and Calibration of CNC Press Brake – Complete Guide | CORMAK

Preparation and Calibration of CNC Press Brake – Complete Guide

Press brake calibration is a crucial procedure to ensure precise bending, repeatability, and long-term performance of the machine. Proper preparation and adjustment of axes and drive systems directly affect product quality. Below you’ll find a detailed step-by-step guide based on industrial standards and CORMAK technology.

Preparation – Foundation for Accurate Calibration

Proper calibration begins with preparation. Clean surfaces, check alignment, and warm up the system to achieve stable, repeatable measurements.

Understanding the Type of Press Brake System

• Hydraulic press brakes – require regular oil level and pressure checks due to fixed-displacement pumps.
• Servo-hydraulic press brakes – use servo-controlled pumps with feedback from linear encoders.
• All-electric press brakes – use servo motors and ball screws for full synchronization, eliminating hydraulics entirely.

Measuring Tools and Equipment

• Digital caliper (accuracy ±0.02 mm)
• Dial indicators with magnetic base
• Straight edges (min. 1 m)
• Feeler gauges (every 0.02 mm)
• Gauge blocks and precision protractors (±0.5°)

Warm up hydraulic or servo systems for 30–60 minutes before calibration. Disconnect power and clean all contact surfaces.

Step 1: Machine Inspection

• Clean bed, ram, guides and backgauge surfaces.
• Check the frame for cracks, loose bolts or visible deformation.
• Verify emergency stop buttons and sensors are functional.
• Run manual ram and backgauge cycles to ensure smooth motion.

Step 2: Geometric Calibration

Parallelism of the Ram (Y1/Y2 Axes)

• Place a straight edge along the bed and lower the ram slowly.
• Measure gaps at five points (center, quarter, and ends).
• Adjust cylinder screws until deviation is below 0.02 mm/m.

Backgauge Positioning (X Axis)

• Set the backgauge to the home position and measure distance to the die edge.
• Repeat at several points; if deviation exceeds 0.1 mm, realign and retighten fasteners.

Step 3: Deflection Compensation (V Axis)

Bed deflection during long or heavy bending is corrected by automatic crowning systems. CORMAK CNC press brakes dynamically adjust pressure to maintain identical angles.

• Perform test bends at 90° on 2 mm steel.
• Measure angles at the center and both ends.
• Adjust until all readings fall within ±0.5°.

Step 4: Tool Setup and Test Bending

• Install punch and die securely with no play.
• Check clearance (0.8–1.2× material thickness) using feeler gauges.
• Perform three test bends and record results.
• If all readings are within ±0.5°, calibration is complete.

Step 5: Production Verification and Maintenance

• Run 20–30 continuous bending cycles with production materials.
• Measure every 5–10 bends to check for angular drift.
• Document results (operator, material, machine, date).

Maintenance Schedule

• Daily: Clean machine and check smoothness of backgauge movement.
• Monthly: Verify geometric accuracy with calibrated blocks.
• Quarterly: Perform full recalibration, or monthly for high-precision operations.

Conclusion

Calibration is an investment in precision and efficiency. A properly calibrated CORMAK CNC press brake ensures repeatable results, reduces waste, and increases tool life. Thanks to advanced servo and hydraulic systems, CORMAK machines maintain stable calibration even in continuous, multi-shift production environments.