The MFJ-1000 runs a 75 kW motor and is rated 6–7 t/h; the 1200 runs 90 kW at 7–8.5 t/h; the 1500 runs 110 kW at 10 t/h. All three share the same construction: a heavy rotor carrying swinging hammers inside a ribbed housing, an inlet at the top, and a curved screen wrapped under the rotor. Material enters, is hit and thrown against the breaker plates until it is small enough to pass the screen, and leaves through the bottom outlet. Nothing else in the machine sets the size.
That is why the screen is the specification to argue about. A 3 mm screen on pallet wood gives a fine sawdust for pellets or mushroom substrate; a 10 mm screen gives a coarse mulch that a compost turner can handle. Changing screens is a ten-minute job on this layout, so one mill can serve two products — but a buyer who orders a single screen and never mentions the end use has bought half a machine.
Feed discipline matters as much on a big mill as a small one. At 10 t/h the inlet is swallowing a steady stream, and a mill fed in shovelfuls runs at 40 percent load with the hammers hammering air. A short inclined belt or a metering bin in front of the inlet is worth more than another 15 kW. Moisture above roughly 15 percent starts to blind the screen, and no amount of motor will push wet sawdust through a blocked hole.
Wood pallets deserve one warning. They are the cheapest feedstock in most yards and the worst for a hammer mill, because the nails, staples and occasional bolt end up in the grinding chamber. The housing and the rotor on this range are built to take that abuse, but the screen is not — a bent screen stops the mill faster than a worn hammer ever will. Yards running pallets should expect to inspect the screen weekly, not yearly.
Zhengzhou Weiwei Machinery has built wood and biomass machinery in Henan since 1980, with CE and ISO 9001 certification. Send us the material, the moisture and the particle size you need to hit, and we will match the model and the screen — because the mill is the easy part and the screen is the decision. Full details are on www.weiweimachinery.com.
