buffer

A buffer is a mechanical device or material positioned between two objects or systems to absorb energy, reduce impact, or isolate unwanted transmission of force or vibration. In practical terms, it sits between a moving part and a fixed structure, or between two moving assemblies, and deforms or flexes when struck rather than allowing the shock to pass through unchanged.

The most common industrial buffer is the elastomeric damper: a block or cylinder of natural rubber, synthetic rubber, or polyurethane bonded to steel plates on top and bottom. When a machine frame experiences a sudden load or impact, the rubber compresses and slowly recovers, converting kinetic energy into heat and spreading the force over a longer time period. Spring buffers work similarly but use a coil or leaf spring instead of rubber; these are stiffer and suit higher-energy impacts. Hydraulic buffers contain a piston inside a cylinder filled with oil; as the piston moves on impact, fluid flows through a small orifice, creating controlled resistance.

Buffers appear in specific high-stress locations: between a press platen and the bolster to cushion each stroke; at the end of a conveyor line to catch moving products; on shock mounts supporting large motors or compressors; and inside machine tool spindle heads to dampen vibration. The buffer must be rated for both the peak force it will experience and the frequency of impacts. A poorly sized buffer either bottoms out (loses effectiveness) or remains so soft it does not attenuate the shock adequately.

Material selection and degradation

Natural rubber buffers cost less and work well in temperature-controlled factories but degrade quickly under ultraviolet light and ozone; synthetic compounds like nitrile or neoprene resist these better. Polyurethane buffers withstand higher temperatures and oils but are stiffer. Age and repeated compression cause permanent set, meaning the buffer no longer fully recovers and eventually stops performing; replacement intervals depend on duty cycle and material choice, typically 2 to 10 years in continuous-duty machines.

The term buffer draws from the idea of buffering, or cushioning, derived from the buff leather used historically in mechanical devices. In modern software and automation, a buffer serves an analogous role: temporary storage that isolates the speed or timing of one process from another, though the mechanism is entirely different.