LaiZhou ChengDa Machinery Co., Ltd.

Daily maintenance of a pellet mill should focus on lubrication, cleaning, gap adjustment, component inspection, operation monitoring, and shutdown protection. Proper attention to these areas helps reduce blockages, abnormal noise, bearing overheating, and die wear, keeping the equipment running steadily.

Pre-shift Inspection and Lubrication

Before startup, check fasteners, belts, chains, oil lines, and electrical wiring to confirm there are no obvious looseness, oil leaks, or abnormal wear. Lubricate roller bearings, main shaft bearings, and other specified points with high-temperature lithium-based grease as required by the manual, and keep the gearbox oil level within the normal range. Lubrication should follow the principles of correct point, correct grade, correct amount, and correct interval. Avoid over-greasing, which may impair heat dissipation, and avoid insufficient grease, which may cause dry running of bearings.

Raw Material Cleaning and Moisture Control

If iron pieces, sand, stones, or other hard contaminants enter the machine, ring die, roller, and bearing wear may accelerate. Screening and iron removal should be carried out before feeding, and a magnetic separator can be installed at the feed inlet. Raw material moisture should also be kept within a reasonable range, generally around 10%–18%, subject to the equipment manual and material characteristics. If moisture is too low, friction will increase; if moisture is too high, die holes may become blocked and pellets may become loose.

Die–Roller Gap Adjustment

The gap between the ring die and the rollers directly affects discharge stability and component service life. If the gap is too small, hard friction may occur, causing rapid temperature rise and accelerated wear. If the gap is too large, the rollers may slip and output may drop. The gap is generally adjusted to about 0.1–0.3 mm. After adjustment, turn the machine by hand to check for smooth rotation and avoid uneven loading on one side. This check should be performed with the machine stopped and power disconnected.

Operation Monitoring

During operation, monitor main motor current, bearing temperature, vibration, and pellet discharge condition. If current fluctuates significantly, pellet formation rate drops, or sharp abnormal noise occurs, reduce the feed rate and investigate the cause promptly. A continuous rise in bearing temperature may indicate insufficient lubrication, improper gap setting, or excessively dry material. Do not continue production under abnormal conditions; stop the machine for inspection to prevent minor issues from worsening.

Shutdown Cleaning and Die Protection

Before shutdown, stop feeding first and wait until the material in the pressing chamber has been discharged before turning off the main motor. To prevent die holes from scaling or blocking, run a small amount of oily material through the machine briefly before shutdown so that the die holes remain filled with oily material. After shutdown, clean residual material from the feeder, conditioner, inner wall of the ring die, and discharge outlet to avoid moisture absorption and caking. During long-term storage, apply rust protection to metal surfaces and disconnect the power supply.

Periodic Maintenance and Wear Part Replacement

In addition to daily maintenance, periodically inspect the wear condition of drive keys, clamps, scrapers, belts, and seals. Replace worn parts such as ring dies, rollers, and bearings when they reach their wear limits to avoid affecting pellet quality and equipment stability. Gearbox lubricating oil can be changed according to operating hours or the manufacturer’s recommended interval. Electrical wiring and control cabinets should also be cleaned and tightened regularly to prevent poor contact.