7 Hydraulic Press Brake Troubleshooting: Expert Solutions For Precision Bending

Hydraulic press brakes are essential machines in sheet metal fabrication and manufacturing industries. They are used for bending and shaping metal sheets into various forms and sizes. Like any other machine, press brakes can experience problems that affect their performance. Hydraulic press brake troubleshootings are the most frequent cause of press brake malfunctions and typically affect force and speed.

The Ultimate Hydraulic Press Brake Repair Guide

Common hydraulic press brake troubleshooting involves the hydraulic system, Hydraulic Leaks, low pressure, Cylinder Sticking, and incorrect Bending. Troubleshooting a hydraulic press brake can be approached systematically to identify and resolve issues. This comprehensive hydraulic press brake repair guide applies to Ermak, Cincinnati, Amada, and JSTMT press brake troubleshooting and solutions that you can refer to daily to minimize production downtime.

Troubleshooting 1: Why Does My Hydraulic Press Brake Lose Pressure? (Causes & Solutions)

Symptom：When insufficient pressure is not applied to the pressure gauge, It may not be just an oil leak, but possibly a blockage in the pilot orifice of the relief valve or a signal drift in the amplifier of the proportional valve。

Solutions:

1. Check whether the positive and negative rotation of the bending machine motor and oil pump are correct

2. Clean the safety overflow valve core of the bending machine

3. Clean the YV1 two position four-way solenoid valve core of the hydraulic system of the bending machine.

4. Check whether the hydraulic pressure valve of the bending machine has internal leakage.

 

 

Troubleshooting 2: Hydraulic Press Brake Ram Drifting Down / Falling Unintentionally 

Symptom：The hydraulic press brake ram falling down could be due to a few reasons. Possible causes include hydraulic leakage, damage to the ram, improper maintenance, or incorrect machine settings. To resolve this hydraulic press brake troubleshooting, it’s recommended to :

 Solutions:

1. Clean the valve core of the small hydraulic control box.

2. Clean the lifting valve core of the hydraulic bending machine.

3. Check the left and right cylinders of the hydraulic bending machine for leakage.

 

Troubleshooting 3: Both Sides Out of Synchronization (Why Is My Press Brake Ram Uneven?)

One of the most frequent questions maintenance engineers ask is: “Why is my press brake ram uneven?” Uneven bending can be caused by an uneven press brake punch and die or a misaligned press brake ram.

For torsion bar synchronous models, an uneven ram is usually due to mechanical linkage looseness or worn components. For electro-hydraulic synchronous models, it is caused by feedback deviation of linear scales or servo valve blockage.

Solutions for Hydraulic Press Brake Ram Alignment::

1. According to the angle error, the hexagonal tube on the bending machine can be adjusted unilaterally by removing it (Delem DA53T/DA66T, Cybelec, or Estun).The Y-axis handwheel can be rotated for 0.10 mm once, and it can be adjusted according to the angle difference.

2. Check whether there is a deviation in the free state of both sides  (0.20-0.30mm is allowed on both sides of the normal range). If the deviation value is not within the range, use the eccentric sleeve on one side to adjust it properly until both sides are adjusted to the allowable range, and then the hydraulic press brake bending machine can be used normally.

 

Root Cause Analysis: Ram Sync vs. Tooling Condition

 

When operators encounter inconsistent angles across the length of the workpiece, the first step is to evaluate the tooling condition. Worn components, such as a deformed V-die or a chipped punch, will directly affect the bend angle regardless of the machine’s hydraulic precision. To maintain proper accuracy, a consistent inspection schedule for all tooling is mandatory.

Dimension	Ram Out of Sync (Tilting)	Tooling Condition
Symptom Description	The ram descends unevenly, causing a linear bend angle variation from left to right (e.g., 90.5° on the left and 89° on the right).	Inconsistent angles that may be irregular. Localized wear can lead to accurate angles in the center but deviations at the ends, or vice-versa.
Core Root Cause	Hydraulic or System Issues: Servo valve signal drift, torsion bar deformation, linear scale feedback errors, or internal cylinder leakage.	Mechanical Wear Issues: V-die deformation, worn components, material fatigue, or misalignment between the upper punch and lower die centerlines.
Technical Keywords	hydraulic issues, control valve, return stroke	tooling condition, worn components, bend angle, inconsistent angles

Advanced Press Braking Techniques: Troubleshooting Bending Defects

Successful press braking relies not only on a well-maintained hydraulic system but also on understanding precision bending mechanics. When operators encounter inaccurate angles, the issue often stems from a mismatch between sheet metal properties and machine settings rather than purely mechanical failure.

To maintain peak efficiency during industrial press braking, operators must monitor tonnage requirements and tooling deflection. If you notice angle variations across the workpiece, ensure your automatic crowning system is calibrated correctly to compensate for the natural deflection that occurs during high-pressure press braking cycles.

 

 

Troubleshooting 4: Excessive Noise and Vibration

Symptom: High-pitched screaming noise from the pump.
Root Cause:Aeration (air entering the hydraulic line via loose suction pipe).
Immediate Action: Tighten all suction pipe connections and check oil level.

 

 

Troubleshooting 5: Leaking oil

Leaking oil can be caused by worn-out seals or damaged hoses. The solution of hydraulic press brake troubleshooting istighten the connections and replace the sensors or wiring if necessary (e.g., checking Estun or Delem controller alarm codes).

 

 

Troubleshooting 6: Electrical problems

Electrical problems can be caused by loose connections, faulty sensors, or damaged wiring. The solution is to tighten the connections and replace the sensors or wiring if necessary (e.g., checking Estun or Delem controller alarm codes).

Troubleshooting 7: System Overheating (Preventing Press Brake Hydraulic Oil Overheating)

Critical system overheating is an issue that directly compromises tooling condition and the longevity of hydraulic seals. If you are experiencing press brake hydraulic oil overheating (where the oil temperature consistently exceeds 60°C / 140°F), the hydraulic oil will lose its viscosity. This directly leads to internal leakage and inconsistent bending angles during high-speed production.

 

Common Causes & Professional Solutions for Oil Overheating

• Blocked Radiator or Heat Exchanger: Dust and metal particles from the workshop can clog the cooling fins. To maintain proper thermal regulation, the radiator must be cleaned weekly using compressed air.
• Faulty Cooling Fan or Pump: If the cooling system is not circulating the oil effectively, it will cause rapid heat buildup. Check the electrical connections and the control valve settings to ensure the cooling circuit is receiving the correct flow.
• High-Pressure Bypassing: If the relief valve is set too low or the control valve is sticking, the system may constantly dump high-pressure oil back to the tank, generating massive heat. This is a common hydraulic issue that mimics a cooling failure.
• Worn Components: A worn-out hydraulic pump creates excessive internal friction and heat. Inspect for worn components if the temperature continues to rise despite a functional cooling system.

 

Symptom	Potential Cause	Action To Solve the Issue
Inconsistent angles	Tooling condition or crowning failure	Inspect for worn components and recalibrate the crowning system.
Weak bend angle	Hydraulic issues in the main cylinder	Check the control valve for internal leakage or debris.
Slow return stroke	Nitrogen pressure or valve lag	Maintain proper pre-charge pressure in the cylinders.
Erratic ram movement	Oil viscosity or air in lines	Flush the control valve and check oil temperature.
Backgauge fails to move	Driver error or parameter loss	Check Estun controller alarm code

 

Regular maintenance and proper use of the hydraulic metal brake can prevent these problems. It is essential to follow the manufacturer’s recommendations for maintenance and industrial machinery manuals. For comprehensive hydraulic press troubleshooting guides, you can send a message to us for a quick reply.