Button-type load cells are compact, high-precision force sensors commonly used in applications where space is limited, yet accuracy and durability are essential. From industrial automation to medical testing equipment and aerospace assembly lines, these small but mighty devices play a crucial role in force measurement. However, when deployed in harsh environments—characterized by vibration, shock, temperature fluctuations, and heavy mechanical stress—button load cells are at risk of damage, particularly due to overloading.
Overload conditions can permanently alter a load cell’s performance, compromise safety, and lead to costly downtime. That’s why implementing robust overload protection strategies is critical for ensuring longevity and accuracy. In this blog, we’ll explore effective overload protection techniques and best practices tailored to button-type load cells operating in tough conditions.
1. Understand the Load Cell’s Overload Rating
Every button-type load cell comes with a rated capacity and an overload limit—typically 150% to 200% of its rated capacity. Exceeding this can cause permanent deformation or sensor failure. It’s important to:
- Select a load cell with a safety factor based on your application’s highest possible load.
- Consider transient loads or shocks that may occur during operation and not just static forces.
2. Use Mechanical Overload Stops
Mechanical stops are one of the most reliable ways to physically prevent the sensor from experiencing excessive force. These include:
- Hard stops: Metal plates or spacers placed to restrict the movement of the load platform.
- Spring-loaded stops: Absorb excess force and distribute it before it reaches the sensor.
- Shims and washers: Can be placed around the load cell to limit compression distance.
This method is particularly useful in dynamic load environments like presses or stamping machines.
3. Incorporate Load Limiters or Shock Absorbers
For applications involving impact forces or sudden load changes:
- Shock absorbers or elastomeric mounts can dissipate kinetic energy before it reaches the sensor.
- Hydraulic or pneumatic dampers may also be used to cushion high-speed loads.
This protection method reduces the chance of both overload and fatigue failure.
4. Electronic Overload Protection
Advanced systems now include electronic load monitoring:
- Sensors feed real-time load data to a controller.
- If force values exceed a preset threshold, the controller cuts off the power or triggers an alarm.
- Can also be integrated into automated testing systems or production lines to reduce human error.
This strategy works best when combined with physical protection measures.
5. Proper Mounting and Alignment
Improper mounting can lead to off-axis loading, which may overload the load cell even if weight limits are within range. For harsh environments:
- Ensure flat and stable surfaces for mounting.
- Use load buttons or adapters to direct force axially.
- Avoid side loading, torque, or bending moments that could distort readings and strain the sensor.
6. Environmental Enclosures and Sealing
Protecting the sensor from moisture, dust, and corrosive elements prevents premature failure, especially in outdoor or marine environments. Consider:
- IP-rated load cells (IP65, IP67, or IP68) designed for rugged conditions.
- Protective bellows, housings, or enclosures to isolate the load cell from the external environment.
- Use of stainless steel materials and hermetic sealing for high-humidity or chemical-prone areas.
7. Routine Inspection and Preventive Maintenance
Even with overload protection, periodic checks are essential:
- Monitor for drift or calibration deviation.
- Inspect for physical damage or fatigue signs.
- Re-calibrate load cells at regular intervals, especially in high-cycle environments.
8. Training and Application Awareness
A common cause of overload is improper usage by operators:
- Train personnel on correct load application methods.
- Label systems with clear weight and force limits.
- Avoid manual processes that introduce unpredictable forces unless supervised.
Conclusion
Button-type load cells are precision tools engineered for accuracy—but they must be protected from harsh environments and overload risks to perform reliably. Implementing mechanical stops, shock-absorbing components, electronic overload detection, and proper mounting can dramatically extend a load cell’s operational life.
When used in extreme settings, every small layer of protection matters. By integrating these strategies into your design and maintenance practices, you safeguard your investment, minimize downtime, and ensure consistent, high-quality data from your force measurement systems.
