LaiZhou ChengDa Machinery Co., Ltd.

Pellet mills are widely used in feed production, biomass pellet manufacturing, chemical processing, and food granulation. While different models vary in structure, the pre-startup preparation and inspection approach is generally consistent: first confirm safety protections, then check mechanical components, lubrication, electrical systems, die condition, and raw material status, and finally conduct a no-load trial run.

Check Safety Protection Devices

Before startup, verify that protective guards, access doors, emergency stop buttons, limit switches, and overload protection devices are intact and functional. Guards must not be removed arbitrarily, and the main unit should not be started when access doors are open. The operating area should be kept clean, with no standing water, oil spills, or scattered materials on the floor, to avoid hazards from slipping or electrical leakage.

Inspect Fasteners and Transmission Components

Manually rotate the main shaft or rotating parts to confirm there is no binding or abnormal noise. Check whether bolts on pressure rollers, ring dies, flat dies, pulleys, couplings, bearing housings, and feeders are loose. Drive belt tension should be moderate—too loose causes slippage, while too tight increases bearing load. Tighten or replace components promptly if looseness or wear is found.

Verify Lubrication and Oil Levels

Check whether oil levels in the gearbox, main shaft bearings, pressure roller bearings, and lubrication pump are normal, and replenish with the specified grade of lubricating oil or grease as needed. For automatic lubrication systems, confirm that the oil pump is operating properly and oil lines are unobstructed. Insufficient lubrication accelerates bearing and gear wear, while excessive oil may impair heat dissipation—follow equipment instructions for proper fill levels.

Check Die and Pressure Roller Clearance

The clearance between the die and pressure rollers directly affects output stability and component service life. For common ring die or flat die pellet mills, the clearance should typically be adjusted to approximately 0.1–0.3 mm before startup, with the exact value determined based on material characteristics and equipment specifications. Too small a clearance accelerates wear, while too large a clearance leads to slippage and reduced output. Adjustments must be made with the machine stopped and power disconnected.

Clean the Pelletizing Chamber and Feeding System

Open the access door and inspect the pelletizing chamber, feeder, conditioner, and magnetic separator for any metal objects, stones, tools, or residual material. Hard debris can damage the ring die, pressure rollers, and cutters. After extended periods, also clear any clogged material from die holes to prevent excessive load during startup.

Inspect Electrical System and Power Supply Conditions

Confirm stable supply voltage, secure cable connections, reliable grounding, and no moisture, dust accumulation, or loose wiring inside the electrical control cabinet. Ammeter and voltmeter readings should be normal, and protective devices should respond reliably. For first-time startup or after maintenance, jog the motor to verify that rotation direction matches the indicated marking, avoiding damage from reverse rotation.

Prepare Raw Materials and Control Moisture and Particle Size

Raw materials should be screened and passed through magnetic separators in advance to prevent metal and hard objects from entering the pelletizing chamber. Moisture content and particle size must meet process requirements—typical moisture levels for biomass and feed pellet raw materials range from 10% to 18%. Oversized particles tend to clog dies, while excessively fine particles may affect pellet formation. Maintain uniform material flow before feeding, and avoid filling the hopper all at once.

Conduct No-Load Trial Run

Before feeding, run the machine without load for 2–5 minutes and observe for abnormal vibration, noise, overheating, or oil leaks. Once no-load operation is confirmed normal, begin feeding with a small amount of material and gradually increase the feed rate. New dies typically require running-in with oily material to gradually smooth the die holes before transitioning to normal production.

In summary, pre-startup preparation for pellet mills should center on "safety protection, secure transmission, adequate lubrication, proper clearance, clean chamber, reliable electrical supply, qualified raw materials, and no-load trial run." Establishing these checks as a standardized routine helps reduce die clogging, abnormal noise, overload, and component wear, thereby improving operational stability.