1. Introducing the die
2. Compensation


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1. INTRODUCING THE DIE

The die is one of the most important parts in the manufacturing of extruded foods. It influences the drying phase and determines the features of the final product, such as shape, colour, cooking performance, etc.

No matter what the desired shape is, the die must nevertheless ensure perfection.

Montoni uses a three dimensional computerized design system (CAD-CAM) which creates the die designs, and manufacturing programs which are then transferred directly to the CNC production machines.

The die is made of essentially two parts:

  • the perforated or shaped support commonly called: DIE BODY or FRAME
  • the forming elements generally called: INSERTS

Dies are generally divided into:

  • circular dies
  • rectangular dies

The dies are used to produce short-cut, long-cut, nest shaped, and sheet pasta as well as snack and breakfast cereal shapes.


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2. COMPENSATION

Friction between the dough and the extrusion head, plus the temperature differential inside the head itself, creates layers of dough moving at different speeds. This is known as laminar flow.

As a consequence, since all the inserts are the same, the extruded shape will have different lengths or thicknesses depending on the extrusion area.

This problem can be partially corrected by working on the die design.

The following is a list of the methods generally used to COMPENSATE, and thus reduce, the flow phenomenon:

  • PRE-DIE

It is a plate which is placed before the die. The holes at the entrance are used to feed the compensation chambers in the perforated area of the die. The chambers are used for compacting the dough and making the pressure more uniform.

The pre-die has the advantage of being suitable for different kinds of dies; on the other hand it cannot be readily adjusted, and therefore it is not always the best solution.
  • COMPENSATION PLATE

They are perforated plates, thinner than the pre-dies, and made specifically for each die. The holes on the plate need to coincide exactly with those of the die.

By having different diameter holes in the plate greater or lesser amounts of dough are fed into the inserts.

  • REDUCER BUSHINGS

These are rings which are placed into the inlet side of the inserts to reduce the amount of dough passing through.

The reducer bushings have the advantage of being attached to the die, but by reducing the supply holes, the die requires a longer cleaning cycle.
  • DIFFERENTIATED FEEDING HOLES IN THE INSERTS

They have to be made during production, and therefore the compensation problem needs to be already studied and understood.

This solution has the advantage of not using other components aside from the die, however the pasta maker must have the necessary expertise to correctly assemble and position the die inserts.



Adjustments for compensation must be made gradually. It is advisable to intervene at the end of every production cycle carrying out the modifications deemed necessary. Improving compensation often requires a lot of time.