Control Methods And Preventative Measures For Quality Problems in Pellet Mill Ring Die Installation And Operation

The ring die is a critical, consumable component of the pellet mill. Proper installation, operation, and maintenance are crucial to improving pellet mill efficiency and reducing consumable part consumption. The following are requirements and steps for proper ring die installation:

1. Pre-installation Inspection and Accessories Selection

The ring die bushing should be inspected weekly for wear.

Original ring die bushings and other accessories should be used to avoid excessive clearance between the ring die, bushing, and drive wheel, which can cause the die to sag naturally and cause impact with the roller during rotation.

2. Installation and Adjustment of Clamps and Bolts

Each time you install or adjust clamp bolts, check the locations shown in the diagram to ensure there is clearance between each clamp and at the three designated locations.

After 30 minutes of normal operation, stop the machine and re-tighten the clamp bolts.

3. Assembly of the Pressure Roller Assembly and Ring Die

After each installation of the pressure roller assembly or ring die, check the position of the pressure roller to ensure it is positioned between the two process grooves of the ring die. If not, adjust the position by installing an adjustment shim between the pressure roller shaft and the pressure plate or main shaft.

After the pressure roller assembly is installed, check the axial clearance between the pressure roller and the ring die to ensure it is no greater than 0.3mm. If not, adjust the clearance by adding an adjustment shim.

4. Ring Die Quality Requirements

Do not use inferior ring dies. The inner wall out-of-roundness of the ring die working surface should be ≤0.20mm to ensure uniform gaps between the die and rollers.

5. Problem Background and Prevention

During normal operation, the ring die, clamp, and drive wheel are secured by clamp bolts, preventing relative movement.

In actual use, wear of the mounting bevels between the clamp, drive wheel, and ring die, as well as loose bolts, can cause relative movement. Combined with the intense compression and vibration of the roller, this can easily lead to cracking of the ring die and wear of the inner tapered hole. This in turn exacerbates wear of the clamp and drive wheel, impacting production and even causing a breakdown or shutdown. The above steps are intended to prevent such problems.