How we build transmission shafts

July 15, 2024

A guide to producing lightweight, energy-efficient transmission components

The use of composite transmission shafts is increasing rapidly in the aerospace industry, as more and more businesses are attracted to the high durability and long fatigue life that they offer whilst remaining a lightweight solution.


Polar Technology are established leaders in the development of lightweight, energy-efficient transmission components, having supplied a variety of shaft assemblies to industries ranging from automotive and motorsport to rail and aerospace.  


Our patented composite to metallic mechanical interface removes reliance on adhesives and enables a more durable shaft, capable of delivering the highest speeds and torques.


Our in-house processes are flexible, depending on the specifications of the product required, but all follow a similar, scalable method that ensures a high-performance solution every time:


Step 1- Winding

Filament winding is a specialist technique, which involves wrapping continuous fibres around a rotating mandrel.


Firstly, the fibres are unwound from spools and run through a series of rollers. They then pass through a resin bath that impregnates the material with an epoxy resin, before being wound onto the mandrel. Alternatively, components can also be wound with pre-impregnated material, which skips the resin bath stage.


The angle at which the fibres are wound onto the mandrel dictates the properties of the final product and defines the strength, stiffness and torsional resistance of the shaft.


Step 2- Curing

After the winding process, the composite material is placed in one of our ovens, where they are cured at specific temperatures and conditions. This process is what binds the composite elements to allow the transfer of loads through the fibres.

 

For the pre-impregnated components, they are cured in one of our autoclaves, which applies up to 150 psi of pressure, to compress and consolidate the composite material.


Step 3- Mandrel Removal and Slitting

For hollow tube structures, the mandrel is extracted from the composite tube and transferred to our machining department for slitting, where our operators will cut the tube to the specified length.


Step 4- Measuring

Our composite wound shafts are carefully inspected to ensure the length, outer and inner diameters meet the required specifications. At this point, the composite shafts will also undergo visual inspection and NDT (Non-Destructive Testing) to ensure that there are no defects which could compromise the structural integrity of the part.


Parts are also measured throughout the build cycle to ensure accuracy is maintained and inspection data is logged on our data capturing system.


Step 5- Pressing

Now the composite structure is ready to have the machined end fittings pressed onto it. Our machine is compatible with a wide variety of tooling to enable different fittings to be applied to the composite shaft.


This is where our patented mechanical interface is utilised, as the composite structure and metallic end fittings are combined solely by applying pressure at either end.  


Once the fittings are attached, bearings can also be added for extra support, if the shaft requires it.


Step 6- Balancing

Shafts will then be taken to our balance machine, which is used to rotate the shafts at a given RPM to analyse any imbalance that may be present.


Any imbalance is then corrected by addition of material through spot welding, and this ensures that the weight distribution along the shaft is neutral and the rotating masses at either end are evenly distributed, thus minimising noise and vibration issues.


Step 7- Testing

The final stage is moving the shaft to our designated quality control area. Using our metrology and inspection facilities, which include CMM machines and portable CMM with laser scanning capabilities, we can check to ensure parts are conforming to the required specification.


Once all tests and inspection criteria for the assembly have passed, we carefully package and send the completed assembly to the customer, ready for integration within their own technologies.




And that is how we produce transmission shafts for a variety of high-performance applications. However, the experience we have in the process of creating wound composite structures is transferrable to all kinds of products for a wide range of industries.  


We also use this method, or adaptations of it, to develop pressure vessels, hydraulic accumulators, composite rotors and more. If you want to find out more about our wound capabilities, click here: https://www.lentuscomposites.co.uk/capabilities


Or if you want to speak to our engineering team to better understand how we can assist your product development, then click here: Contact (polartechnology.co.uk)


December 10, 2024
We have recently installed a brand-new filament winding machine as part of a designated, world-class manufacturing cell
November 20, 2024
A step-by-step guide to the process of creating composite pressure vessels for the storage and transport of fluids and gases at high pressures
November 6, 2024
View our interactive guide to find out more about our full capabilities and previous experience in high-performance projects.
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