מחשבון מהירות טיפ

Tip speed (also called peripheral velocity) is the linear velocity at the outermost point of a rotating tool — the blade tip or hammer tip. It is the single most important parameter governing cutting performance, particle size, and energy consumption in size reduction equipment.

Formula: v = π × D × n / 60, where D is diameter in meters and n is RPM.

Tip speed directly determines:

• Cut quality: Higher speed = finer particles and cleaner cuts
• Material throw: Material ejection distance increases with tip speed
• Power consumption: Power is proportional to v³ (cube of velocity)
• Tool wear: Abrasive wear increases sharply with tip speed

Too low: poor cutting, material wrapping around rotor. Too high: excessive wear, wasted energy, safety risks.

It depends on the material being processed:

• Green vegetation: 30–50 m/s
• Woody brush: 50–65 m/s
• Stumps & heavy timber: 60–80 m/s
• Wood chipping (clean cuts): 25–40 m/s

Many mulchers operate at 50–65 m/s as a compromise for mixed material.

Higher tip speed generally produces finer particles and smoother cuts, but the relationship is complex:

• Particle size is also controlled by screen aperture size
• Number of tools and their spacing affect cuts per revolution
• Feed rate vs. rotor speed ratio determines chip thickness
• Beyond optimal speed, no further quality improvement — only more wear

High tip speeds create extreme forces and hazards:

• Centrifugal force: At 80 m/s, a 2 kg hammer on R=300mm experiences ~2,175 g — about 43 kN of force on the retaining pin
• Projectile risk: Thrown objects can reach tip speed — 225+ km/h
• Tool retention: Pins, bolts, and welds must be rated for centrifugal + impact loads
• Rotor balance: High-speed rotors require dynamic balancing to G6.3 or better
• Guard integrity: Housing must contain thrown tools and material