Part geometry and mandrel model

Axisymmetric and non-axisymmetric part geometries

The simulation concept allows CADWIND to calculate the fiber lay-up for any part geometry: from simple axisymmetric geometries like tubes to complex non-axisymmetric geometries like elbows and T-fittings.

CADWIND’s mandrel model generator

CADWIND has its own integrated mandrel model generator with which mandrel geometries most common to filament winding technology can be generated quickly and easily:

  • any type of axisymmetric components such as cylindrical tubes, conical tubes, pressure vessels, tanks with various endings (spherical domes, ellipsoidal domes, parabolic domes, conical endings, straight extensions)
  • non-axisymmetric components such as tubes, pressure vessels or tanks with rectangular or elliptical cross sections
  • curved components such as elbows with circular, rectangular or elliptical cross sections
  • T-parts

Import from CAD software or other sources

CADWIND can import mandrel models from other CAD software via the DXF format. It is also possible to create mandrel models using other software such as spreadsheets and load them directly into CADWIND.

typical axisymmetric part geometry (pressure vessel)
typical non-axisymmetric part geometry (pipe elbow)

Winding simulation and pattern calculation

CADWIND's iWind algorithm
the iWind parameter and the list of found winding patterns
The friction modelling allows to vary the winding angle. In the middle section we have a higher angle. This results in a thicker laminate. You can see that by using the color scale.
the color scale

iWind: CADWIND’s unique and innovative filament winding algorithm

iWind is CADWIND's innovative and ground-breaking algorithm for the simulation of the filament winding process and for the calculation of fibre paths and winding patterns. A multitude of new features enables the user to create optimal winding patterns even easier and faster. It produces instant results on the screen as parameters are changed, allowing for fast experimentation, and provides a complete list of possible winding patterns.

Physical modelling

CADWIND’s iWind algorithm’s main feature is the physical modelling of the winding process. This unique simulation concept, proven since more than 30 years, is much more powerful then any analytical geometrical formula.

The winding and material parameter

Calculating the winding with iWind is very simple. All you have to do is to enter the winding parameters and iWind automatically finds a whole list of possible winding patterns. The winding parameters are:

  • the winding’s start position and direction on the mandrel
  • which area of the mandrel surface should be covered by the winding
  • the orientation of the fibre (the winding angle)
  • the friction factor for the friction modelling
  • the fibre's width

For the calculation of the laminate thickness and weight CADWIND uses the following material parameters:

  • the density of the filaments and the resin or matrix
  • the fibre volume fraction or the fibre mass fraction
  • the linear weight (the weight per length) of the filament or roving

Non-geodesic winding by friction modelling

CADWIND's simulation concept includes the modelling of the friction between the fibre and the mandrel. This friction allows to deviate from the geodesic path (i.e. the shortest distance between two points on a curved surface) without slipping, thus offers a much wider range of design and production possibilities.

Winding patterns

The complete coverage of the mandrel surface can only be reached by the cyclic repetition of a fibre path. An important requirement is that the fibres are placed evenly around the mandrel circumference. The result is a closed winding pattern. Physically and mathematically only certain winding patterns are possible.

iWind finds a whole range of possible winding patterns. These are displayed in a detailed table with all their properties. The list can be conveniently sorted, grouped, filtered and searched so that you can quickly and easily choose the optimal winding pattern for your application.

Calculation of the laminate thickness, laminate weight, winding path length and fibre consumption

CADWIND calculates the thickness of the resulting laminate for each point of the winding. Additionally, the total weight of the laminate as well as the total length of the fibres used are calculated.

Mandrel shape update

In general filament wound laminates contain several layers. With each layer, the mandrel increases in size and changes its shape slightly. It can be necessary to update the mandrel’s shape for the next layer. CADWIND simplifies this task. It allows you to take into account the thickening caused by the layers and to update the mandrel model accordingly.

Variation of the winding angle

The friction modelling allows the winding angle to be varied in different regions of the part. A good example for the use of this feature are masts for sailboards. The different winding angles allow the rigidity to be varied along the mast.

Layer linking

CADWIND can link different layers (e.g. a pressure vessel with a low angle helical winding and a circumferential winding) so that the part can be wound easily without stopping the machine. As a result, the production time is reduced considerably.

Fast parallel processing

iWind is extremely fast. Thanks to its parallel processing structure it uses the full power of all CPU cores.

Live View: Learn about the physics of fibre placement on curved surfaces

iWind has a new Live View function. When Live View is enabled, you can change any parameter by using sliders and immediately see the results. This allows you to instantly see what effect this parameter has on the result. This makes it very easy to quickly familiarize yourself with the filament winding process and to achieve optimal results.

The color scale

CADWIND offers a color scale, which indicates the winding angle, the winding angle deviation and the laminate thickness at any point of the winding by coloring the laminate.

Machine simulation and manufacturing

Any machine or robot

CADWIND runs on any filament winding machine or robot.

CADWIND generates the part program for any type of machine and controller. No matter if a simple 2 axes machine or a complex 6 axes winder, a specialized T-winder or a winding robot, CADWIND's part programs run on every kind of machine or controller.

Real-time machine simulation

CADWIND fully visualizes the winding process. It provides a real-time animation of the machine actually winding the fibers. This gives you a much better idea of what to expect when the winding program is applied to the machine. You can keep track of the machine's movements and their dynamics, see whether the winding program is running smoothly, if the range of an axis is exceeded or the pay-out eye collides with the mandrel.

Machine Motion Analyser

Another handy tool is the graphical display of the displacement-time, speed-time and acceleration-time diagrams of the machine movement which allows you to analyse the dynamics of the machine in detail.

Optimal machine dynamics

CADWIND gives you full control over the dynamics of the machine movement. As a result, the control data can be optimized according to different aspects like reducing production time, winding with constant mandrel speed or constant pay-out speed.


The machine simulation and the flexibility of CADWIND allows the system to adapt to a high degree of automation. For example special commands for the automated attachment and cutting of the fibers can easily integrated in the part program.

The machine simulation shows the different machine axes and the workshop floor and displays the positions of the machine numerically.
Machine Motion Analyser

Design and analysis

finite element analysis (FEA)

Design and finite element analysis

CADWIND fully integrates with any Finite Element Analysis (FEA) program to predict and analyse the mechanical properties of filament wound parts. With CADWIND's DESIGN PACK extension you can export all the necessary data (part geometry, laminate structure, stacking sequence, fiber orientation, thickness) from all points of the part to any FEA program (not for Ts). The DESIGN PACK also includes the COMPOSITE STAR laminate analysis software.