Roth Composite Machinery’s filament-wound hydrogen tanks

New drive technologies based on hydrogen or natural gas, for example, are becoming increasingly important in the context of resource-saving mobility. Type IV pressure vessels are suitable for the economical storage of these drive media in vehicles.

They are based on a thermoplastic liner, which achieves the necessary pressure stability through fiber reinforcement in the filament winding process.

Type IV containers are characterized by their enormous lightness and safety, making them highly attractive for numerous mobility applications. Roth Composite Machinery from Steffenberg has the necessary know-how and experience in the development and construction of machines for the production of such containers.

Numerous filament winding systems from the company are in use worldwide by well-known manufacturers for the production of high-pressure containers for gases. Each plant is planned and designed to precisely fit the requirements of the customer’s application. Consultation by the mechanical engineer includes the sequence of individual production steps, material selection and processing, degree of automation and productivity increase, right through to commissioning and instruction in the operation of the plant.

Hydrogen container in the filament winding process

Roth Composite Machinery recently delivered a custom-designed filament winding line for the production of hydrogen containers with three spindles. Dr. Andreas Reimann, managing director at Roth Composite Machinery, explained, “A powerful drive concept combined with a new machine frame structure enable performance increases of around 40 percent compared to the international state of the art.”

The machine concept features five interpolating axes and five additional CNC-programmable auxiliary axes. The machine setup is suitable for both series production and development (R&D) applications using the traditional wet winding process.

The impregnation station allows individual use of individual spindles through separation to avoid unnecessary consumption of resin. An NC-controlled doctor blade allows precise and reproducible resin gap adjustment. The traveling impregnation station is suitable for processing both carbon fibers and glass fibers and reduces roving stresses due to reduced wrap angles.

With the yarn storage device, even very low yarn tensions can be adjusted to suit the process due to the double cylinder control. Uniform yarn take-off speeds of up to 4.5 meters per second are possible. The machine is prepared for easy conversion to the towpreg winding process.

The degree of automation of the machine is increased by the use of the ROTH-RCA (automatic tying and cutting of the fibers). For the winding of pressure vessels, for example, the setup features, among other things, an automatic pressurization and measuring system that can build up and regulate the necessary liner internal pressure during the winding process. The extreme machine rigidity minimizes mechanical influences on the manufacturing process and ensures maximum precision during filament winding.

State-of-the-art technology

Filament winding systems from Roth Composite Machinery enable manufacturing processes in the traditional wet winding process as well as for towpreg applications.

Roth Composite Machinery has further developed the spool holders on the spool stand for the system described – they make it easier to load full spools and remove empty cores. A CNC-controlled counter-bearing ensures precise positioning during set changes, thus saving setup times and compensating for length deviations of the plastic liners within the tolerance range.

The clamping pressure of the quills can be adjusted via proportional valves in the program.
The new filament winding machine is designed to be versatile – it can be used for small, light components as well as for large, heavy ones, thus offering a wide production spectrum.