Do pneumatic cylinders need cleaning?

1. Why is it necessary to clean cylinders?

Prevent external debris from entering and damaging the seals and cylinder barrel:
Dust and debris: These hard particles can scratch the cylinder's piston rod. Scratches on the piston rod surface can directly damage the rod seal, leading to air leaks.

Even more seriously, if impurities are carried into the cylinder through the piston rod, they can further scratch the inner wall of the cylinder barrel and piston seal, causing internal leakage, resulting in insufficient output, slow, or unstable cylinder movement.

Ensure smooth operation and prevent jamming:
In harsh environments (such as machine tool processing, food production, and woodworking workshops), oil, dust, and sticky substances can accumulate on the piston rod, increasing movement resistance, causing the cylinder to operate awkwardly or even suddenly jam, disrupting production.

Maintain system cleanliness and protect the entire circuit:
Wear particles or contaminants inside the cylinder can flow back into the airflow, contaminating precision components such as the solenoid valve and speed control valve, and causing a cascading failure.

Easy to check and find hidden dangers in advance:
The cleaning process itself is an excellent inspection opportunity.
You can carefully check: 
Piston rod: Is there any scratch, rust or bend?
Mounting parts: Are the screws loose?
Buffer adjustment: Is it effective?

2. How to clean the cylinder correctly?

(1). Daily/external cleaning (no disassembly required)

Safety first: cut off the air supply and exhaust the compressed air in the pipeline to ensure that the equipment does not malfunction.
Wipe the piston rod:
Let the cylinder run until the piston rod is fully extended.
Dip a clean cloth in kerosene or diesel and wipe the exposed piston rod to remove oil and impurities on its surface.
Dry it with another dry cloth.
This is the simplest and most effective daily maintenance and can prevent 80% of failures.

(2). Regular/internal deep cleaning (disassembly required)

When the cylinder malfunctions, leaks internally or externally, it needs to be disassembled and cleaned.
Disassembly:
Mark the cylinder's inlet and outlet ports and installation direction.
Carefully disassemble the cylinder end cover, piston, seal, etc. in order. Pay attention to the components of the buffer mechanism.
Cleaning parts:
Soak all metal parts (cylinder barrel, piston rod, end cover) in kerosene or diesel. Scrub thoroughly with a soft-bristled brush to remove all sludge and impurities. Do not use metal brushes.
For stubborn stains, use a non-metallic scraper to carefully remove.

Inspection and Replacement:
Focus on checking for longitudinal scratches on the cylinder bore and piston rod surfaces. Minor scratches can be repaired with a fine oilstone; more severe scratches require replacement.
Key Steps: After disassembly, it is generally recommended to replace all seals (such as O-rings, Glyd Rings, and Step Seals) with new ones. Old seals may have aged and deformed, making them more likely to leak after reassembly.

Reassembly and Lubrication:
Dry all parts with compressed air.
Evenly apply pneumatic grease to the cylinder bore, piston rod, and all seals.
Carefully reassemble in the reverse order of disassembly, ensuring that the seals are properly seated and free of twisting or shearing.
When tightening bolts, apply force evenly across the entire diagonal plane.

3. Cleaning Frequency and Precautions

Frequency:
Daily: Wipe the piston rod after each shift. Regular inspection: Disassemble and inspect the unit every 3-6 months or annually, depending on the operating environment.

Contraindications:
Do not use strong solvents such as gasoline and acetone, as they can damage seals.
Do not use compressed air to blow directly on seals, as this may cause rapid aging or damage.
During assembly, avoid missing or damaging seals.