**4.6 Pultrusion process**

Composite pultrusion is a processing method for producing continuous lengths of fibre-reinforced polymer structural shapes with constant cross-sections. This is a continuous fabrication method that can be highly automated. In this process, a continuous bundle of dry fibre is pulled through a heated resin-wetting station.

**Figure 9.** *The schematic of the filament winding process.*

**4.8 Additive manufacturing**

*Introduction to Composite Materials*

*DOI: http://dx.doi.org/10.5772/intechopen.91285*

*The schematic of the automated fibre placement process.*

**Figure 11.**

toolmaking [53–56].

**Figure 12.**

**19**

*The schematic of the 3D printing process for polymer composites.*

**4.9 Composite properties**

Additive manufacturing is also known as 3D printing technique. Additive manufacturing is a step change in the development of rapid prototyping concepts that were introduced more than 20 years ago. This is a process for making a solid object from a three-dimensional digital model, typically by laying down many successive thin layers of a material. Manufacturing a composite structure with a single nozzle uses polymer composite filament and contains polymer and additives such as rubber microspheres, particles of glass or carbon fibre, wood flour, etc. as shown in **Figure 12**. This more recent form of composite part production grew out of efforts to reduce the costs in the design-to-prototype phase of product development, taking aim particularly at the material-, labour-, and time-intensive area of

The polymer composite materials are lightweight, which increases the fuel efficiency of vehicles manufactured from composites and gives them structural

**Figure 10.** *The schematic of the pultrusion process.*

The wetted bundle is pulled into heated dies, and the cross-sectional shape of the pulled fibre is formed by these dies. The resin is cured, and the composites are formed. Parts are then made by slicing the long-cured piece. This process is limited to straight parts with a constant cross-section, such as I-beams, T-beams, or frame sections and ladder rails. **Figure 10** shows the schematic of the pultrusion process [49, 50]. Pultrusion is used in the manufacture of linear components such as ladders and mouldings.
