Hydraulic Pressure Switch Failure in Roll Forming Machines – Causes, Fault Signals, Inspection & Repair Guide
Hydraulic Pressure Switch Failure
Roll Forming Machine Hydraulic & Pneumatic Failure Guide
Hydraulic pressure switch failure is a hydraulic control and safety system problem in roll forming machines where the pressure switch responsible for detecting hydraulic pressure levels fails to operate correctly, causing incorrect control signals or safety shutdowns.
Pressure switches are commonly installed in roll forming machine hydraulic systems to monitor pressure levels and provide electrical signals to the machine control system.
Unlike pressure gauges that display pressure visually, pressure switches automatically trigger electrical signals when hydraulic pressure reaches a preset threshold.
These switches help control many automated machine functions such as:
activating hydraulic cut-off systems
triggering punching operations
confirming cylinder pressure before movement
protecting hydraulic pumps from low-pressure operation
activating safety shutdown conditions
When hydraulic pressure reaches the set value, the switch changes its electrical contact state and sends a signal to the PLC or machine control system.
However, if the switch fails to operate correctly, the machine may receive incorrect pressure signals.
This condition is known as hydraulic pressure switch failure.
Pressure switch failure 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 pressure switch failure include:
machine refusing to start hydraulic functions
unexpected hydraulic system shutdowns
incorrect pressure alarm signals
hydraulic cycles not activating
PLC fault messages related to pressure sensors
intermittent hydraulic system operation
If the pressure switch fails to detect correct pressure conditions, the machine may either stop functioning or operate unsafely.
Maintaining reliable pressure detection is critical for hydraulic system control.
Causes of Wear or Failure
Hydraulic pressure switch failure usually occurs due to mechanical wear, electrical faults, or contamination inside the switch mechanism.
Several factors may contribute to this condition.
Mechanical Switch Wear
Internal springs and contacts may wear over time.
Contamination in Hydraulic Oil
Debris may block the pressure sensing port.
Electrical Contact Damage
Repeated switching may damage internal contacts.
Improper Pressure Calibration
Incorrect settings may cause improper operation.
Wiring Damage
Broken or loose wires may interrupt signals.
Excessive Pressure Spikes
High pressure may damage the sensing element.
Why It Happened and What Caused It
From an instrumentation engineering perspective, hydraulic pressure switches operate by sensing hydraulic pressure through a small internal diaphragm or piston.
When hydraulic pressure reaches the preset threshold, the pressure force moves the internal sensing element.
This movement activates an internal electrical switch that changes the state of electrical contacts.
The signal is then transmitted to the machine’s PLC or control system.
However, over time the internal mechanical components may wear due to repeated switching cycles.
Contaminated hydraulic oil may also enter the sensing port and interfere with the diaphragm movement.
Additionally, electrical contacts inside the switch may degrade due to electrical arcing.
When these components fail, the switch may no longer activate at the correct pressure level.
Routine inspection and proper hydraulic filtration help maintain pressure switch reliability.
How to Inspect the Problem
Inspection Procedure
Diagnosing pressure switch failure requires inspecting both the hydraulic sensing system and the electrical control circuit.
Step 1 – Verify Hydraulic System Pressure
Use a calibrated pressure gauge to confirm actual system pressure.
Step 2 – Inspect Pressure Switch Activation
Check whether the switch activates at the correct pressure.
Step 3 – Inspect Electrical Wiring
Verify that wiring connections are secure.
Step 4 – Inspect the Pressure Sensing Port
Ensure the sensing port is not blocked.
Step 5 – Check PLC Input Signals
Confirm that the PLC receives the correct switch signal.
Step-by-Step Technician Guide – How to Fix
Correcting pressure switch failure usually requires replacing the faulty switch or repairing electrical connections.
Method 1 – Clean the Pressure Sensing Port
Remove contamination blocking the sensing pathway.
Method 2 – Adjust Pressure Switch Settings
Calibrate the switch according to system requirements.
Method 3 – Repair Electrical Wiring
Fix loose or damaged wiring connections.
Method 4 – Replace the Pressure Switch
Install a new switch if the internal mechanism is worn.
Method 5 – Test System Operation
Verify that the switch activates at the correct pressure.
Preventative Maintenance Tips
Preventing pressure switch failure requires maintaining clean hydraulic oil and proper electrical connections.
Maintain Hydraulic Filtration
Clean oil prevents contamination of sensing components.
Inspect Electrical Connections Regularly
Secure wiring prevents signal interruptions.
Test Pressure Switch Operation
Routine testing verifies correct activation pressure.
Protect Sensors from Pressure Spikes
Install pressure dampeners if necessary.
Replace Aging Sensors
Periodic replacement prevents unexpected failure.
FAQ Section
What causes hydraulic pressure switch failure in roll forming machines?
Mechanical wear, contamination, or electrical faults may cause switch failure.
Can a faulty pressure switch stop machine operation?
Yes. Incorrect pressure signals may prevent hydraulic functions from activating.
How can pressure switch failure be detected?
Incorrect pressure alarms or failed machine cycles may indicate the problem.
Should faulty pressure switches be replaced?
Yes. Reliable pressure monitoring is essential for safe machine operation.
Can contaminated hydraulic oil damage pressure switches?
Yes. Debris may block the sensing port.
How can pressure switch failure be prevented?
Proper filtration, routine inspection, and correct pressure settings help prevent failure.