Different production techniques for carbon tubes explained

EXPLAINED
Different production techniques for round carbon tubes.

Standard carbon tubes can be distinguished in four different basic types in which the choice depends on the performance you are looking for in your application. These four types basically have different fibre directions, which results in different bending and torsional performance. In addition, there is also a considerable price difference between the four types.

PRICE
PERFORMANCE
FINISH
FOR SALE
Pultrusion
Low
Single
Low
No
Pullwinding
Middle
Multi
Middle
Yes
Prepreg
High
Multi
High incl lacquer
Yes
Filament Winding
High
Multi
High
Soon
PRICE
PERFORMANCE
FINISH
Pultrusion
Low
Single
Low
Pullwinding
Middle
Multi
Middle
Prepreg
High
Multi
High incl. lacquer
Filament Winding
High
Multi
High
Pultrusion Technique

Pultrusion is a continuous production process whereby dry carbon fibres are pulled through a resin bath and then through a heated core. The profile then passes through an oven for curing. The last step is to cut to lengths of maximum 6m. As no transverse fibres are applied, the tube stiffness is therefore only longitudinal. In this way, a pultrusion tube cannot absorb torsional loads. The exterior is unpainted and without fabric finish.

Pullwinding Technique

In this technique, the base tube is produced in a similar way to a pultrusion tube, but a rotation winding is applied in the process, usually at a 30 to 90 degrees angle. This gives the tube a versatile performance character for both bending and torsion loads. The fibre distribution for standard pipes is approximately 80% in the longitudinal direction and 20% in the transverse direction (90°). The exterior is unpainted but has a winding finish.

The production process  of the “Industrial Performance” tube is based on the pullwinding technique.

Prepreg Technique

The prepreg technique, also known as roll-wrap, uses impregnated carbon fabrics that are laminated around a core in different orientations. The fibre structure in this type of production is both the longitudinal (0°) and transverse (90°). The standard tube has approx. 80% in longitudinal direction (UD) and 20% in transverse direction. A carbon fabric is applied as a top layer to ensure a high-quality exterior finish. This fabric can be made in both ‘Plain’ and ‘Twill’ look. As standard, the tubes are finished with a high-quality high-gloss lacquer. Optionally a matt finish is available.

The “High Performance”, “High Precision”, “Carbon Kevlar” and “Ultra Lightweight” tubes are all produced  with the prepeg technique.

Filament Winding Technique

Individual filaments of reinforcement are run through a resin bath and wound onto a mandrel. Wind angles can be adjusted through process setup parameters to vary the strength characteristics of the tube to meet specific application requirements. The maximum length of the tubes is 6m.