Retyre AS (previously known as Technium AS) was rewarded with the MANUNET Transnational call in 2018. Together with SINTEF and ICPE, Retyre AS formed a consortium set out to develop manufacturing in the tire industry. Project name was “Automation in pre-vulcanization of tyres and assembly line automation”
Manunet is a network of Governments under the European framework Programme targeted towards achieving co-ordinated calls to finance R&D in manufacturing
1. Background and aim of the project
ReTyre has commercialised a modular tyre system suitable for bicycles, wheelchairs, strollers, and E-scooters. The original modular tyre technology consists of a detachable tread surface (skin) and a base tyre. The base tyre has incorporated means of attachment (zippers) alongside the tyre sidewall that can connect with a “skin” (typically a winter tread pattern with spikes) that contains the opposite side of the attachment means.
1.2 Aim of the project
The aim of this project was to
- Increase the manufacturability and product quality through innovations in processes and tools
- Improved coherence between product design and capabilities in manufacturing
- Strengthened scalability of the modular tyre solutions
- Facilitate for recyclable materials in large scale for the modular tyre solution to make an impact towards a sustainable industry
2. Results from the project
As some of the results are still not ready to be disseminated due to IPR rights, we will offer a limited scope of the project in this blog post:
2.1 A scalable method of vulcanising tyre tread without carcass (relates to WP 1/WP3)
The original idea was to refine the current production method of regular tyres to also support vulcanising carcass-less skins. However, we wanted to take this solution to another level, so instead of optimizing the operation of the green tyre on the airbag, we set ahead and developed a whole new way of thinking.
Eventually the solution was to design a skin with a flat geometry, as opposed to circular tyre moulds in the tyre industry. If you take a closer look at the flat geometry (see Figure 1), you can see that the geometry is not entirely flat, it has a wavy structure in both the lateral and longitudinal direction, that allows the finished vulcanised tyre tread to be “popped out” in a circular shape after demoulding. The optimal geometry to facilitate this behaviour is calculated used advanced inhouse algorithms. The solution has been verified and commercialised and the finished product can be seen in Figure 1. We call it Substantial Flat Moulding (SFM).
One of the main advantages of this process compared to the regular tyre build process is that the vulcanising step can be performed with two interlocking metal-moulds, whereas the original tyre moulding process consists of one metal part and one rubber Air Bag. The result is that with a metal-to-metal mould one can achieve a much higher pressure and thus can control the thickness precisely. For the Air bag method, any extra rubber put in the mould cannot be squeezed out and thickness will vary greatly from product to product.
Figure 1: This Figure show how the SFM process works. The tyre is produced flat with a wavy structure, after it comes out of the mould it will "pop" out in a circular shape. On the right side you can see the finished product in real life
2.2 An electronic solution for counting zipper teeth (relates to WP 2)
An electronic handheld device for counting zipper teeth has been developed by ICPE. It is designed as an embedded system with PCB, LCD-screen, and optic sensors (see Figure 2). It can count the teeth in both direction of zipper direction. It has been implemented in QC of incoming components (zippers) in the reTyre Factory and has served as an important implementation. In the future it is also possible to implement it directly into the jigs, so that the teeth number can be controlled in the assembly in real time.
Figure 2: Left: embedded device, right: zoomed in on the track that guide the zipper through the optic sensor