Hydraulic Seal Extrusion in Roll Forming Machines – Causes, Seal Damage, Inspection & Repair Guide

Seal Extrusion

Roll Forming Machine Hydraulic & Pneumatic Failure Guide

Seal extrusion is a hydraulic system failure in roll forming machines where a hydraulic seal is forced into the clearance gap between moving components due to excessive pressure, causing deformation or damage to the seal.

Hydraulic systems in roll forming machines rely on seals to maintain pressure and prevent hydraulic oil leakage within components such as:

hydraulic cylinders
control valves
hydraulic pumps
pressure regulators
accumulators

These seals are typically made from elastomer or polymer materials and are designed to fit tightly within grooves or sealing cavities inside hydraulic components.

During normal operation, seals maintain contact with metal surfaces and prevent hydraulic oil from escaping.

However, hydraulic systems operate under high pressure, and small gaps may exist between moving metal components.

If the hydraulic pressure becomes too high or if the seal material becomes weakened, the seal may be forced into these gaps.

This condition is known as seal extrusion.

Seal extrusion may affect roll forming machines producing:

metal roofing panels
metal wall cladding panels
standing seam roofing systems
structural deck profiles
C and Z purlins
light gauge steel framing components

Typical production symptoms associated with seal extrusion include:

hydraulic oil leakage
loss of hydraulic pressure
damaged or deformed seals
reduced cylinder performance
irregular hydraulic actuator movement
increased hydraulic system noise

If seal extrusion continues, the damaged seal may eventually fail completely, allowing large amounts of hydraulic oil to bypass the sealing surface.

Maintaining proper hydraulic pressure and correct seal selection helps prevent this failure.

Causes of Wear or Failure

Seal extrusion usually occurs when hydraulic pressure or mechanical conditions exceed the design limits of the sealing system.

Several factors may contribute to this condition.

Excessive Hydraulic Pressure

Pressure beyond design limits may force seals into clearance gaps.

Large Component Clearances

Worn components may create larger gaps.

Improper Seal Material

Incorrect seal materials may lack sufficient strength.

High Operating Temperature

Heat may soften seal materials.

Hydraulic Pressure Spikes

Sudden pressure surges may stress seals.

Incorrect Seal Installation

Improper installation may weaken seal positioning.

Why It Happened and What Caused It

From a hydraulic engineering perspective, seals operate within carefully designed clearances between moving components.

These clearances allow mechanical movement while still maintaining sealing performance.

However, if the pressure acting on the seal becomes too high, the force applied to the seal may push it toward the nearest clearance gap.

If the gap is large enough, the seal material may deform and enter the gap.

Once the seal begins to extrude into the gap, the sharp edges of metal components may cut or damage the seal material.

This damage may lead to seal tearing, leakage, and eventual hydraulic failure.

Seal extrusion is more likely when components wear over time and clearances increase.

Using properly rated seals and maintaining correct system pressure helps prevent seal extrusion.

How to Inspect the Problem

Inspection Procedure

Diagnosing seal extrusion requires inspecting hydraulic components and monitoring system pressure behavior.

Step 1 – Inspect Hydraulic Cylinders

Look for oil leakage around piston rods.

Step 2 – Inspect Sealing Surfaces

Check seals for deformation or damage.

Step 3 – Monitor Hydraulic Pressure

Excessive pressure may cause seal extrusion.

Step 4 – Inspect Component Clearances

Check for wear between moving components.

Step 5 – Inspect Seal Material Condition

Look for softening, cracking, or deformation.

Step-by-Step Technician Guide – How to Fix

Correcting seal extrusion usually requires replacing damaged seals and correcting hydraulic system conditions.

Method 1 – Replace Extruded Seals

Install new seals with proper specifications.

Method 2 – Install Backup Rings

Backup rings help support seals under high pressure.

Method 3 – Reduce Hydraulic Pressure

Adjust system pressure if necessary.

Method 4 – Repair Worn Components

Restore correct clearances in cylinders or valves.

Method 5 – Use Correct Seal Materials

Install seals rated for system pressure and temperature.

Preventative Maintenance Tips

Preventing seal extrusion requires maintaining correct hydraulic system pressure and component clearances.

Monitor Hydraulic System Pressure

Avoid operating beyond design limits.

Maintain Hydraulic Component Condition

Replace worn components to maintain proper clearances.

Use Proper Seal Materials

Seals must match system pressure requirements.

Install Backup Rings Where Required

Backup rings help support seals in high-pressure systems.

Perform Routine Hydraulic Inspections

Regular inspection helps detect early seal damage.

FAQ Section

What causes seal extrusion in roll forming machines?

Excessive pressure, worn components, or improper seal materials may cause seal extrusion.

Can seal extrusion cause hydraulic leaks?

Yes. Damaged seals may allow hydraulic oil to escape.

How can seal extrusion be detected?

Oil leakage, deformed seals, or pressure loss may indicate extrusion.

What are backup rings used for?

Backup rings support seals and prevent extrusion under high pressure.

Can worn components cause seal extrusion?

Yes. Increased clearance between parts may allow seals to deform.

How can seal extrusion be prevented?

Maintaining correct pressure, proper seal materials, and component clearances helps prevent this failure.