The maintenance of pneumatic piston rods is the key to ensuring their long-term stable operation and extending their service life. Regular inspection, cleaning, lubrication, and component replacement can effectively prevent issues such as wear, leakage, and jamming. The following are detailed maintenance steps and key points:
1、 Daily inspection and cleaning
Visual inspection
Surface of piston rod: Check for scratches, dents, rust, or peeling coating. Minor scratches can be repaired with oilstone polishing, while severe damage requires replacement of the piston rod.
Sealing condition: Observe whether the piston sealing ring, piston rod sealing ring, and dust ring are aging, cracked, or deformed. If any leakage or dust intrusion traces are found, the seal should be replaced immediately.
Connection part: Check if the connecting bolts between the cylinder end cover, piston rod, and load are loose to prevent detachment due to vibration.
Cleaning treatment
Remove impurities: Wipe the surface of the piston rod with a clean soft cloth to remove dust, oil stains, and metal shavings. Avoid using corrosive cleaning agents such as gasoline and acetone.
Dust prevention measures: In dusty environments, protective covers or accordion covers can be installed to reduce the intrusion of external impurities.
Example: The food industry requires wiping with food grade alcohol to avoid contaminating products.

2、 Lubrication management
Lubrication method selection
Manual lubrication: suitable for low-frequency and low-speed scenarios (such as manual fixtures). Inject a small amount of lubricating grease (such as lithium grease) into the guide sleeve and seals with an oil gun every 500 hours of operation or every week.
Automatic lubrication: In high-frequency and high-speed scenarios (such as automated production lines), it is recommended to install a centralized lubrication system and provide timed and quantitative oil supply.
Oil air mixture lubrication: For scenarios with extremely high speed requirements (such as pneumatic sliding tables), an oil air mixture device can be used to achieve continuous and uniform lubrication.
Lubricant selection
Low temperature environment (below -20 ℃): Use low-temperature lubricating grease (such as molybdenum disulfide based grease) to avoid hardening and cracking of seals.
High temperature environment (above 100 ℃): Silicon based or fluorine based grease is used, which is resistant to high temperatures and non-volatile.
Corrosive environment: Use chemical resistant lubricating grease (such as polyurea based grease) to prevent reaction with acidic and alkaline substances.
Lubrication cycle control
Light load scenario (load<1000 N): lubricate every 2000 hours or 3 months.
Overload scenario (load ≥ 5000 N): lubricate every 500 hours or 1 month.
Adjustment basis: Flexible adjustment based on actual operating frequency, load size, and environmental conditions.

3、 Seal replacement and maintenance
Determination of seal failure
Leakage phenomenon: Continuous exhaust from the cylinder exhaust port or oil stains on the surface of the piston rod indicate damaged seals.
Sports jamming: The expansion or deformation of the seal may cause the piston rod to move unevenly, and it needs to be replaced in a timely manner.
Life expectancy: Polyurethane (PU) seals have a lifespan of approximately 5000-10000 hours, while fluororubber (FKM) seals can reach over 20000 hours.
Replacement steps
Disassemble the cylinder: turn off the air source, release residual pressure, and remove the end cap fixing bolts.
Remove the piston component: Use a specialized tool to remove the piston and avoid scratching the inner wall of the cylinder.
Replace the seal: Use a sharp blade to cut off the old seal ring, clean the seal groove, and install the new part (pay attention to the direction, such as the U-shaped ring opening facing the pressure side).
Assembly test: Assemble in reverse order, manually push the piston rod to check if it moves flexibly, and reinstall after there is no leakage.

4、 Monitoring of operating parameters
Pressure and flow monitoring
Pressure gauge installation: Install pressure gauges at the inlet and outlet of the cylinder to monitor whether the actual working pressure is within the design range (usually ± 10% fluctuation).
Flow meter usage: By using a flow meter to detect cylinder air consumption, abnormal increase may indicate seal leakage or piston jamming.
Adjustment method: If the pressure is insufficient, check whether the three components of the air source treatment (filter, pressure regulating valve, oil mist device) are blocked or damaged.
Speed and travel calibration
Speed regulation: Use a throttle valve to control the movement speed of the piston rod, ensuring it matches the equipment rhythm (such as assembly line requirements of 0.3~0.8 m/s).
Travel limit: Regularly check the position of magnetic switches or mechanical limiters to prevent piston rod overtravel and impact damage.
Example: If the impact sound is too loud when the piston rod moves to the end, it is necessary to adjust the opening of the buffer valve or increase the external buffer.

5、 Environmental adaptability maintenance
temperature control
Low temperature start-up: In an environment below -10 ℃, preheat the cylinder with a heater to above 0 ℃ before start-up to avoid seal cracking.
High temperature heat dissipation: For continuously running cylinders, install heat sinks or forced ventilation devices on the outer wall of the cylinder to prevent excessive internal temperature.
Explosion proof and dust-proof measures
Explosion proof cylinder maintenance: Regularly check whether the explosion-proof junction box and grounding wire are intact to ensure compliance with ATEX or IECEx standards.
Dust proof level upgrade: If the original IP65 protection is insufficient, it can be replaced with IP67 or IP69K level cylinders to adapt to harsh working conditions.

6、 Fault prevention and emergency response
Common faults and causes
Bending of piston rod: reasons include eccentric load, worn guide sleeve, or unstable cylinder support. Need to recalibrate the load center or replace the guide sleeve.
Early failure of seals: may be caused by insufficient lubrication, high air pressure, or invasion of impurities. Need to strengthen lubrication and cleaning management.
Cylinder crawling: caused by uneven friction, can be solved by adjusting the lubrication amount or replacing low friction coefficient seals.
Emergency response plan
Leakage emergency: If the seal leaks slightly, the end cap bolts can be temporarily tightened or the working pressure can be reduced; Serious leakage requires immediate shutdown and replacement of seals.
Stuck handling: Use a wooden mallet to lightly tap the cylinder end cover and try to remove the jam; If it is ineffective, it is necessary to disassemble and inspect whether there are foreign objects or damaged parts inside.

7、 Maintain records and archive management
Maintenance Log
Record the maintenance time, content (such as cleaning, lubrication, component replacement), operating parameters (pressure, speed), and abnormal situations for each maintenance.
Example:
Date Maintenance Content Pressure (MPa) Speed (m/s) Remarks
Replace the piston rod sealing ring 0.58 0.6 on March 1, 2024. The original sealing ring has aged and cracked
Lifetime tracking
Establish a lifespan record for key components such as piston rods and seals, predict replacement cycles, and avoid sudden failures.
Example: If the average lifespan of a cylinder seal is 8000 hours, spare parts can be prepared in advance at 7500 hours.

8、 Professional maintenance and training
Regular professional maintenance
Every year or 20000 hours, professional engineers conduct comprehensive maintenance, including cylinder wall wear measurement, piston coaxiality testing, etc.
Testing tools: Use high-precision equipment such as laser alignment instruments and internal micrometers to ensure the quality of maintenance.
Operator training
The training content covers daily inspections, lubrication operations, simple troubleshooting, etc., to improve equipment self maintenance ability.
Assessment criteria: Operators must be able to independently complete basic maintenance tasks such as seal replacement and pressure adjustment, and pass practical assessments.