How to Synchronize Hydraulic Cylinders: a Comprehensive Guide

Proper synchronization of double-acting hydraulic cylinders is critical to ensure a smooth and efficient machine operation. At Cylinders, Inc, we specialize in double-acting hydraulic cylinder repair and understand the importance of having cylinders move in unison. When cylinders are out of sync, it leads to inconsistent motion, excessive wear, and mechanical issues.

By correctly synchronizing your hydraulic cylinders, you can maximize performance, avoid downtime, and extend the lifespan of your equipment. Our knowledgeable team has put together this article to help you understand the synchronization process and the benefits of having expertly synchronized cylinders for optimal functioning.

How Hydraulic Systems Work with Multiple Cylinders

Hydraulic systems that utilize multiple cylinders require precise synchronization between the cylinders to function properly. Without proper synchronization, the cylinders will move sporadically and out of sequence rather than in tandem. Expert synchronization aligns the cylinders so they operate in perfect coordination, which enables smooth and efficient system operation. Technicians use various methods to synchronize hydraulic cylinders such as flow dividers, counterbalance valves, and flow control valves.

The Role of Hydraulic Valves and Controls in Synchronization

Hydraulic valves and controls play an important role in enabling cylinder synchronization within a hydraulic system. Components like directional control valves actively regulate and direct the flow of hydraulic fluid to synchronize cylinder movements. Flow control valves manage the speed and rate of fluid flow to ensure smooth, controlled motion. Counterbalance valves are also key for controlled synchronization by compensating for external forces on the cylinders. Proper valve setup, control, and adjustment are pivotal factors in effectively synchronizing multiple hydraulic cylinders for optimum performance.

Get Prepared for Synchronization

The proper preparation ensures hydraulic systems are ready for synchronization.

Ensure Safety and System Integrity

As you can imagine, synchronizing hydraulic cylinders requires careful preparation. Technicians need to consult OEM procedures where available, always wear proper PPE and follow safety protocols. Cylinders, valves, pumps, and lines are precision machined and rated for the expected pressures. Hydraulic fluid and filters are checked. Rods, seals, and mounts are inspected for wear and leaks. Venting safely releases trapped air. Verifying all components are in good working order before attempting to synchronize the system prevents failures or accidents.

Inspect Your Hydraulic Cylinders

Next comes inspection. Proper hydraulic cylinder maintenance increases the chances of successful synchronization. Technicians will inspect cylinder rods, seals, chambers, and bores for signs of damage or wear, and seals and wipers will be replaced to prevent leaks. Cylinder mounts are checked for looseness while contamination is flushed from the system. Slave cylinders are tuned to match the flow divider or control valve. It's ideal to perform thorough cylinder inspection and maintenance before attempting synchronization to prevent malfunctions or leaks.

Identify the Need for Synchronization in Your Specific Application

Is synchronization truly needed? This determination can help prevent over-engineering. Consider the loads, lifting heights, cycle rates, and position accuracy required. Weigh factors like cost, complexity, and maintenance. Another consideration is that synchronization may only be critical in a portion of the cycle. Look for binding or wear that causes unsynchronized motion. If needed, you can discuss needs with cylinder and valve suppliers. Carefully evaluating the application identifies where and how synchronization benefits performance, safety, and efficiency.

Top Challenges in Hydraulic Cylinder Synchronization

Synchronizing multiple hydraulic cylinders can present some unique challenges:

• Synchronizing multiple cylinders (3 or more): More cylinders make precision alignment difficult;
• Double-acting cylinders: Both extension and retraction strokes must be synchronized;
• Wear and tear over time: Synchronization can get thrown off as cylinders age;
• Temperature fluctuations: Cylinders may behave differently as the hydraulic fluid heats up;
• Load and pressure changes: External forces can affect cylinder movements;
• Contamination in fluid: Particles can obstruct smooth cylinder motion;
• Mechanical issues: Damaged seals, rods, etc. impair smooth operation;
• Improper valve controls: Unsynchronized flow rates between cylinders;
• Flexible hoses: Can distort and cause alignment issues;
• Loose mountings: Cylinders not rigidly aligned to each other;
• Operator error: Improper control adjustments during operation.

What Are Common Hydraulic Cylinder Synchronization Techniques?

Various techniques enable hydraulic cylinders to move in precise synchronized motion.

1. Mechanical Linkage

Mechanical linkages physically couple the hydraulic cylinders to synchronize their motion. Linkages such as bars, gears, or pulley systems interconnect two or more cylinders. As one cylinder extends or retracts, it mechanically drives the attached cylinders to move simultaneously. Mechanical linkages offer a simple, cost-effective way to synchronize small numbers of hydraulic cylinders in applications like lifting platforms or bucket excavators.

2. Active Load Sensing Controls

Active load sensing is an advanced yet simple solution for synchronizing hydraulic cylinders. It utilizes a closed-loop hydraulic circuit with pressure sensors on the cylinders. This allows the system to actively balance the pressures by regulating pump flow. Continuous adjustment allows the cylinders to remain synchronized. Active load sensing is a cost-effective, responsive way to achieve precision cylinder synchronization without complex electronics. For most applications, it's an ideal advanced technique for this critical synchronizing task.

3. Electronic Control Systems

Electronic control systems use sensors, valves, and controllers to actively synchronize hydraulic cylinders. By monitoring cylinder positions and loads, the control system can respond in real time to ensure equal flow and pressure to each cylinder. This closed-loop feedback control continually adjusts to maintain precise synchronization, even when load conditions are changing. Electronic control provides adaptive, intelligent cylinder synchronization for demanding applications.

4. Proportional Valve Control

Proportional valves enable accurate flow control for synchronizing hydraulic cylinders. By proportionally regulating oil flow to each cylinder, the valves can divide flow evenly. As loads change, proportional valves dynamically adjust oil flow to match cylinder pressure demands, keeping the cylinders synchronized. Proportional valve control systems provide responsive, adaptive cylinder synchronization without complex electronics. This simple, cost-effective method works well for many applications.

Best Practices for Safe and Efficient Cylinder Synchronization

Synchronizing hydraulic cylinders follow a methodical sequence for peak accuracy and performance.

Set up the Hydraulic System

The first step in synchronizing hydraulic cylinders is proper system setup. Cylinders must be installed and linked according to the application. Required valves, pumps, reservoirs, and sensors are mounted and connected via hydraulic lines. The right hydraulic fluid is selected and added to the specifications and bleeding removes air pockets. This critical preparation ensures cylinders have the surrounding infrastructure for smooth pump actuation and synchronization before calibration and testing. If you take the time to methodically set up the hydraulics, it can prevent issues down the line.

Calibrate the System

Once the hydraulic system is installed, calibration tuning achieves synchronization. Cylinders are set to zero positions as a baseline point and sensors are calibrated to properly track cylinder extension. Valves are adjusted for equal division of flow rates. Calibration verifies cylinders will move in unison through full stroke ranges before connecting loads. Taking the time to fine-tune calibrations prevents synchronization issues when the system is operational under real loads.

Test and Fine-Tune

After calibration, hydraulic cylinder synchronization systems require testing and fine-tuning. Cylinders are run through full motion cycles while monitoring for synchronization. Control parameters are adjusted to fix any lagging or leading cylinders. Pressure, flow rate, and response settings are tweaked to perfect synchronization. Iterative testing refines the system until cylinders move precisely in unison for the intended loads and cycles. Careful testing and tuning ensure optimal real-world synchronization performance.

Troubleshoot Common Synchronization Issues

Even with proper setup, calibration, and testing, issues can occur with hydraulic cylinder synchronization. Technicians methodically troubleshoot by checking position sensor accuracy, hose pressures, flow rates, and valve response. Contamination, hydraulic leakages, or mechanical binding are other common problems. Isolating the out-of-sync cylinder and components points to the root cause and addressing synchronization problems as they arise prevents damage from position shifts or uneven lift.

Additional Considerations for Synchronization Accuracy

Achieving precise hydraulic cylinder synchronization requires more than just installation and calibration. Additional factors can also significantly impact accuracy.

Keep in Mind Cylinder Size, Stroke Length, and Performance Match

When synchronizing hydraulic cylinders, the cylinders must be properly sized and matched to enable precise synchronized movement. Differences in cylinder bore, rod diameter, stroke length, or performance can reduce synchronization accuracy. Identical cylinder size and stroke capabilities allow for smooth, even extension and retraction. Furthermore, cylinders must be able to handle the system pressure and flow rates without binding or lagging. Proper sizing, selection, and matching of cylinders is crucial for precise control and synchronization.

Ensure Proper Fluid Flow Distribution and Pressure Control

Achieving accurate synchronization requires properly regulating hydraulic fluid flow and pressure to the cylinders. The flow must be evenly divided using valves or other distribution methods. The system should provide adequate flow rates and pressure from pumps and hydraulic oil to avoid lag or binding. Continuous monitoring and control of pressure allows on-the-fly adjustments to maintain synchronization. From distribution to real-time modulation, managing fluid flow and pressure is essential for precise and responsive control when synchronizing hydraulic cylinders.

Address Load Imbalance and Over-Travel Issues

Load imbalances and over-travel can disrupt synchronized cylinder movements. If cylinders are lifting uneven loads, flow and pressure differences will push one cylinder ahead. Over-travel and extending further than needed also gets cylinders out of sync. Compensation methods like flow control valves or counterbalance valves help prevent these issues. In addition, careful system design and monitoring help identify and address potential synchronization problems from load imbalances or over-travel when synchronizing hydraulic cylinders.

Conclusion

Synchronizing hydraulic cylinders is critical for optimized system performance, safety, and efficiency. We encourage operators to follow the best practices for installation, calibration, troubleshooting, and maintenance to achieve precise synchronized cylinder motion. At Cylinders, Inc., we're a top double-acting cylinder rebuilder that understands the importance of proper synchronization. In addition, if one of your synchronized cylinders is beyond economical repair, Cylinders can re-manufacture a matching cylinder to assure synchronized movements are maintained.

By researching synchronization methods, inspecting your hydraulic components, and addressing errors proactively, you can advance your hydraulic system to new levels of productivity. Don't let cylinder synchronization issues hold you back - take action now and experience the benefits of efficient hydraulic cylinder operation. Contact us today to schedule your repair and unlock the full potential of your hydraulic system.