ก turbo mill plant fiber modification line grinds and coats fiber in one machine. The RTM turbo mill breaks up fiber clumps and sprays the coupling agent inside the same grinding chamber, so the activation index reaches target while fiber length survives.
Customer Background
The customer processes crop straw fiber for biodegradable plastics and wood-plastic composites. The plant sits in Shandong and ships modified fiber to compounders and board makers.
Before the project, the plant ran two machines. A mechanical mill reduced fiber size. A high-speed mixer coated the surface. A screw conveyor moved fiber from one to the other.
ความท้าทาย
Ground plant fiber clumps. The fibers are hydrophilic, and they stick together once the mill releases them. The downstream mixer could not reach the surface of every particle, so coating drifted from batch to batch and the activation index fell below target.
Mechanical grinding cut the fibers short. Impact mills break fiber into pieces and leave hairy tails on the ends. Short fibers lower the length-to-diameter ratio, which weakens the reinforcement effect in the finished composite. The customer wanted smaller particles and a higher aspect ratio at the same time.
Two machines cost more to run than one. Separate grinding and coating doubled the handling, dust collection, and energy per ton, and the batch mixer set the pace for the whole line.
The Solution
Epic Powder proposed a single machine for both steps: the RTM Turbo Mill Coating System.
The RTM is a rotary turbo mill. Its rotor and stator carry impact pins. As the rotor turns at 100–120 m/s, the pins strike the fiber, the gap between rotor and stator shears it, and the fibers rub against each other. A metering pump sprays a liquid modifier silane through nozzles into this zone, so the coating lands on fiber surface while that surface is fresh.
An air classifier sits on top of the mill. It returns coarse particles for regrinding and passes only the finished cut, so one pass gives the target particle size distribution.
Epic Powder specified the RTM 500 model for this line. The RTM 500 carries a 45 kW motor and four blade layers, and it adjusts across 50–2500 mesh.
Plant fiber is heat-sensitive, so the RTM runs a large volume of cooling air and holds the outlet temperature low. A hot-air option dries fiber during milling and removes a separate drying step. The line runs under negative pressure, and a PLC panel stores a recipe for each fiber type and modifier ratio.
ผลลัพธ์
The line targets an activation index of 96% or higher, measured as the share of powder that floats on water.
Fiber arrives at 8–12% moisture. The hot-air option dries it in the mill and brings moisture to 7% or below, the industry ceiling for extrusion and injection molding. High-performance compounds often run below 3%.
Coating during grinding uses 15–30% less coupling agent than a separate mixer. The modifier meets fiber surface that is fresh and still moving; a separate mixer coats fiber that has already cooled and clumped.
เหตุใดจึงสำคัญ
One machine replaces two steps. Coating inside the mill removes the batch mixer and the conveyor between machines, which cuts handling and dust. Fiber keeps more of its length. The rotor shears fiber, so more of the length-to-diameter ratio survives and the fiber carries more of its reinforcement load.
A uniform coating raises filler loading. Compounders can load more fiber into PLA and PBAT. The RTM Turbo Mill Coating System is Epic Powder’s documented equipment for bio-based fiber processing, alongside the company’s mills for mineral and battery powders.
ข้อมูลจำเพาะทางเทคนิค:
วัสดุ: Crop Straw
Particle Size: D50 of 100–150 μm
เอาท์พุท: 800–1,200 kg/h