How to determine if a medical caster has reached the end of its service life?

Determining whether a medical caster has reached the end of its service life requires a comprehensive assessment based on three core dimensions: functional failure, safety hazards, and performance degradation. This involves visual inspection, operational testing, and risk assessment to determine when to replace the caster. Specific indicators are as follows:

1. External wear and structural damage: Visual signs of failure

Severe wheel wear

Cracks >1mm deep, chipping, or irregular wear (such as single-side flattening) on the wheel surface, resulting in rolling wobble and deviation;

The rubber/PU wheel body becomes hardened, sticky, or swollen (due to aging caused by long-term exposure to disinfectants), losing its elasticity and causing a noticeable increase in rolling noise (over 70 decibels);

The wheel diameter decreases due to wear, resulting in a height difference >5mm from other casters, causing the equipment to tilt. Rusted or deformed metal parts
Extensive rust on the wheel frame and axle (rust coverage >30%), especially in load-bearing areas, with the risk of rust penetration;
The wheel frame is bent or cracked, or the wheel-to-frame connection is loose (wobble >3mm), resulting in an unusual metallic friction noise when pushed;
The brake pedal is deformed or broken, or the brake pad is severely worn (thickness <1/3 of its original thickness), failing to fully conform to the wheel surface.

2. Functional Failure and Safety Hazards: Core Replacement Basis
Unreliable Braking System
After applying the brake, the caster continues to roll (on a horizontal surface) even when a 50N thrust is applied, or it slides on its own on a 3° incline;
The brake-unlock cycle is slow, requiring repeated application of the brake pedal to unlock, making it impossible to quickly move the equipment in an emergency;
The caster frame continues to rotate when the universal wheel is braked, losing the directional locking function. Decreased Rotational Performance
The universal wheel cannot rotate smoothly 360°, jams and lags when turning, and significantly increases pushing resistance (requiring a force greater than 50N, far exceeding the normal <30N);
Bearings lock or make unusual noises (such as creaking), and vibrations occur during rotation, affecting equipment stability (such as deviations in precision instrument readings).
Insufficient Load-Bearing Capacity
After loading the rated weight, the caster exhibits noticeable sinking (wheel frame compression greater than 5mm), or the axle bends when pushed;
After repeated heavy loads, the connection between the caster and the equipment becomes loose (such as thread stripping on the lead screw or falling off the flat screw), posing a risk of equipment tipping.

3. Failure to Restore Performance After Maintenance: End-of-Life Signs
After maintenance, including cleaning, lubrication, and tightening, the following issues persist:
Core functions such as brake failure and steering jams remain unchanged;
Wheel wear or metal corrosion continues to worsen (such as the reappearance of noticeable rust within one week after cleaning);
Material degradation frequently occurs after contact with disinfectants (such as cracking of silicone wheels or swelling of PU wheels), compromising safety.

4. Reference Use Cycles and Industry Standards
Ordinary medical casters (PU wheels + 304 stainless steel frames) typically have a lifespan of 1-3 years under standard use. High-frequency, heavy-load equipment (such as hospital beds) is recommended to undergo a comprehensive inspection every 1.5 years.
Cleanroom silicone casters have a relatively short lifespan (1-2 years) due to their material characteristics, so they should be evaluated in advance based on disinfection frequency.
If the equipment manufacturer clearly specifies a caster replacement cycle (e.g., the manual recommends 2 years), adhere to the standard to avoid extended use.

Summary
When a medical caster exhibits severe wheel wear, brake failure, structural corrosion and deformation, or fails to meet safe operating requirements even after maintenance, it has reached the end of its service life and requires immediate replacement. A routine "regular inspection + functional testing" log should be established, focusing on the condition of casters on high-frequency and high-risk equipment (such as ICU beds and operating room carts) to eliminate safety hazards.