texfash: Cetia has developed proprietary systems capable of automatically separating and sorting up to 120 shoes per hour. Given the complexity of footwear construction, especially with glued, sewn, injected, and vulcanized soles, what were the primary technical challenges in developing this technology, and how does it compare in efficiency and accuracy to manual disassembly methods?
Chloé Salmon Legagneur: Generally speaking, glued shoes are processed on our tear-off line, which includes an oven to heat and reactivate the glue on the shoes and a robot to exert a tearing force to separate the sole from the upper (the upper part of the shoe). The rates quoted above are an average and vary according to the dismantling recipes (temperature, heating time, robot speed, etc.). Our line is an industrial pilot that enables us to refine the dismantling recipes before processing larger volumes.
Depending, for example, on the type of assembly, the type of glue and the materials making up the shoe, we can have different recipes. All the tests we have carried out with shoe brands have enabled us to refine these recipes according to these specificities. Given the diversity of models and the need to standardise dismantling parameters, upstream sorting offers a clear advantage. To this end, we have developed the IDSHOES solution, which enables shoes to be identified and sorted by type, brand and, where applicable, model if entered in our database. This gives us greater control over the batches processed on this line.
Our aim is to transfer this industrial solution to players wishing to target this type of solution, with the possibility of resizing the heating and stripping system according to the specifications required.
We also have a water-jet cutting line, enabling us to separate the sole from the upper, for heavily stitched or injected shoes. Two high-pressure water-jet heads enable us to make precise cuts. Different cutting modes can be used, either a predefined trajectory (offset), or a trajectory drawn by the operator with a stylus, or a trajectory defined automatically by a vision system coupled with AI. Cutting is precise and efficient, but we recover less material from the sole, compared with tearing off glued shoes.
The integration of the Valvan Fibresort machine allows Cetia to sort textiles by composition and colour at a rate of one garment per second. How does this high-speed sorting impact the quality and purity of recycled fibres, and what measures are in place to handle garments with mixed or unknown fibre compositions?
Chloé Salmon Legagneur: The machine is designed to provide reliable composition prediction at these speeds. To detect the composition, Valvan uses a NIR sensor that takes several local measurements as the garment passes through. This solution offers us modularity in terms of sorting recipes (settings for the desired compositions) and flexibility in the allocation of sorting bins (up to 10 sorting bins in the version present at Cetia). This machine processes single and multi-material garments, giving details of the percentages of materials detected.
These sorting rates make it possible to define pools of qualified, homogenous materials that can be fed to the rest of the recovery chain, such as mechanical recyclers.
Other manufacturers, such as PELLENC, PICVISA and TOMRA, to name but a few, also offer detection and sorting solutions for managing large textile flows.
We also have a multi-sensor line (SENSOR HUB, developed by Cetia and financed by the Refashion eco-organization), integrating various technologies including a NIR sensor, various cameras such as a hyperspectral camera, and a non-destructive X-ray inspection technology. These tools enable us to carry out a complete analysis of the items being processed, and to offer tailor-made solutions to meet specific needs.
