Assembly Instructions for Ring Die & Roller of Ring Die Feed Pellet Mill

Pre-assembly Mandatory Requirements

1. Cut off all power supply, implement lockout-tagout procedure.
2. Clean residual materials and metallic impurities inside the pelleting chamber. Polish all mating surfaces to remove rust and hard deposits.
3. Inspect spare parts: Ensure no cracks on ring die and all die holes are unobstructed; check roller bearings rotate smoothly and oil seals remain intact.
    
   Do NOT assemble new ring die with worn rollers, or new rollers with used ring die.

1. Ring Die Assembly Steps

1. Positioning & Alignment

    

   Lift the ring die into position. Align the inner drive slot of ring die with the drive key on the hollow main shaft. Fully seat the drive key into the slot. Never hammer the ring die forcibly.
2. Install Clamping Hoop & Bolts

    

   Fit the ring die clamping hoop and high-strength fastening bolts.

    

   Tighten bolts diagonally in several passes instead of locking one bolt fully at once. Uniform stress prevents ring die deformation.

Reference torque value: Approx. 45～50 kg·m for SZLH series. Stop machine and retighten all bolts after 30 minutes of operation.

3. Coaxiality Inspection

    

   Rotate the main shaft manually for one full revolution. Check the ring die has no obvious runout or scraping. Reassemble and calibrate locating surfaces if eccentricity occurs.
4. Temporary Protection

    

   After ring die installation, loosen all roller adjusting screws to move rollers away from ring die inner surface, to avoid scratching die holes during roller fitting.

2. Roller Assembly (Prone-to-error Critical Process)

1. Pre-assemble Roller Unit

    

   Disassemble roller housing, install bearings and oil seals. Fill the housing with high-temperature resistant grease (60%~70% cavity volume; overfilling causes overheating). Fit end cover, lock washer and round nut, then bend lock washer to secure the nut.

    

   Rotate roller shell manually; it should turn freely without jamming or excessive axial play.
2. Mount Roller Unit onto Eccentric Shaft Base

    

   Install roller assembly on the eccentric adjusting shaft.

    

   ✅ Critical Orientation Rule: When rotating the eccentric block in the same rotating direction as ring die, the roller shall move closer toward ring die. Wrong assembly direction will lead to jamming and choking during operation.
3. Uniform Arrangement of Multiple Rollers

    

   Dual-roller model: Symmetric left-right layout.

    

   Triple-roller model: Equally spaced at 120° to guarantee balanced load distribution.

3. Clearance Calibration between Ring Die and Rollers

Standard clearance: 0.1～0.3 mm

1. Adjust each roller screw gradually to bring roller shell close to ring die inner wall.
2. Turn ring die by hand. Ideal state: rollers slightly contact the die and tend to rotate with light friction.
3. Calibrate every roller sequentially to keep consistent clearance and avoid one-sided abrasion.
4. Lock the lock nuts of adjusting screws after calibration to prevent clearance shift during production.

• Clearance ＞0.4 mm: Roller slipping, low output, fragile pellets.
• Clearance ＜0.05 mm: Severe dry metal friction, rapid wear, abnormal noise and overheating.

4. Post-assembly Inspection & Run-in for New Die/Rollers

1. No-load Test Run

    

   Close the machine door. Run without load for 5～10 minutes. Listen for no impact or scraping noise, check roller temperature rise is normal.
2. Mandatory Run-in for New Ring Die & Rollers (Not Skippable)

    

   Prepare run-in mixture (raw material + fine quartz sand + small amount of edible oil). Feed material at low speed for 30～60 minutes, then gradually increase load. The run-in polishes inner die holes. Never run new die/rollers at full load directly.

5. Common Assembly Prohibitions (Main Cause of Failures)

6. Supplementary Maintenance Notes for Reassembly

1. Check deformation of ring die drive key and key slot.
2. Replace roller oil seals preferentially to stop materials entering bearings.
3. Stop using ring die with deep inner grooves; flip for reuse or repair if possible.