In REX Next Generation, you have the option of defining specific mould elements in order to calculate key process variables such as the pressure at the screw tip. This function is particularly relevant for the precise simulation and optimisation of plastics processing, as the geometry of the mould elements has a direct influence on the material flow and pressure distribution.

REX Next Generation provides you with a range of predefined tool elements that can be used in the simulation. These tool elements cover the most common cross-section shapes used in practice. The following elements are available:

• Conical circular cross-section: This element describes a circular cross-section whose diameter varies over its length. This geometry is often used for transitions or nozzles that guide the material into a narrower area.

• Conical rectangular gap: A rectangular cross-section whose width and/or height varies along the length of the mould. This geometry is often used for tools that need to ensure an even distribution of material over a larger area.

• Conical annular gap: An annular gap with a tapered diameter. This geometry is often used in applications where the material flows radially around a core, such as pipe extrusion.

• Circular cross-section: A simple circular cross-section with a constant diameter. This is a commonly used geometry for nozzles or inserts that focus the material flow onto a circular orifice.

• Rectangular gap: A constant rectangular cross-section that ensures an even distribution of material over a rectangular area. This cross-section is often used in flat film extrusion processes.

• **An annular gap with a constant diameter, often used in processes where the material is discharged in a circular strand, such as in the production of pipes or hoses.

You can define specific geometry sizes for each of these mould elements. These variables are crucial for the precise simulation of the material flow and the pressure conditions within the mould. The common geometry parameters that you can define include:

* Diameter (for circular cross-sections) * Width and height (for rectangular cross-sections) * Gap height (for annular gaps) * Length of the mould

By entering these parameters, you can ensure that the simulation accurately reflects the actual physical properties of the mould, which leads to realistic results.

In addition to the geometry, you can name each tool element individually to better organise and identify the different components within the process. This is particularly helpful when several tool elements are used in a process.

Another important feature is the ability to specify the number of elements connected in parallel. This makes it possible to use several identical mould elements in parallel in a process in order to simulate the material flow through several channels simultaneously. This function is particularly useful for processes with multi-channel or multi-strand extrusion.

To enable a precise visualisation of the entire tool, you can flexibly arrange the tool elements. The right arrow, left arrow, up and down buttons are available for this purpose. You can use these buttons to

• Add new tool elements: You can add further elements to the list in order to design the structure of the tool in detail.
• Move elements: If you want to change the order of the elements, you can use the arrow buttons to move them to the desired position. This is particularly useful to ensure that the tool elements are used in the correct order in the simulation.

The precise definition and arrangement of the mould elements is crucial for the quality of the simulation results. By taking into account the various geometries and their influence on the material flow, you can perform precise calculations, such as the pressure at the screw tip or the speed of the material outlet. These parameters are of great importance in plastics technology, as they have a direct influence on the quality of the end product.

• Input of a die characteristic (REX)
• Definition of a Die geometry (REX)
• Definition of a Die geometry (PSI)