Basic rules for the correct use of pellet mill die

1. Make sure that the rollers are correctly adjusted: the minimum distance from the die must be 0.2-0.3 mm. The wrong setting of the rollers can cause the contact between the rollers and the die. This may cause ‘roll over’ of the holes in the die – deformation and partial closing of the holes

2. When changing dies, carefully assess the condition of the die seating surfaces and of the fixing systems (collar, clamp or wear ring). Careful: if the die is not properly fixed it can break.

3. The die clamping rings should be checked every time a new die is put on the pellet mill, especially for those dies designed with big flanges. From experience, in the majority of cases where a die has broken the cause has been due to a worn out or defective clamping ring. Dies running with a defective clamping ring can give rise to strong vibrations, die breakage and reduced die life.

Main factors affecting die life during pellets production

The life of a pellet mill die depends on many factors:
– the composition of the raw material (formulation)
– the characteristics of the raw materials used in the pellets production
– the fat content
– the particle size of the mash
– moisture content before pelleting
– the thermal conditioning of the mash
– the pellet mill control automatics / manual
– others

Composition: compositions rich in fibre as those in rabbit feed are harder to pellet and therefore the life of the dies is much shorter: for instance, if the life of a die is 1 when used to make rabbit feed, it is 4 when used for cattle feed and 5 when used on poultry feed.

Characteristics of the raw materials: raw materials contain silica / sand wears dies more rapidly

Fat content: formulae containing 1.5-2% fat run smoother and are less abrasive, the fat acts as a lubricant.

Particle size of the mash: a mash with a large particle size is more abrasive

Moisture content and thermal conditioning of the mash: a poorly conditioned mash is drier and harder to pelletizing process

Press control: the operator should regularly check the state of wear on the deflectors and scrapers and also the roll adjustment: to avoid uneven wear on the die and consequently inefficient pelleting. The state of wear on the conditioner paddles: to ensure efficient pre-conditioning. Steam traps and filters: to ensure that no condensate is being passed into the conditioner.