Today's KNOWLEDGE Share : Toray has developed a high-speed thermal welding technology

Today's KNOWLEDGE Share

Thermosets still dominate aerospace structures. Toray Industries, Inc. shows that thermoplastics can already be welded to them.

Toray has developed a high-speed thermal welding technology that forms a thermally weldable layer on the surface of #carbonfibrereinforced thermoset or thermoplastic components, allowing parts to be joined by rapid heating without adhesive or mechanical fasteners, & enabling thermoset-to-thermoset, thermoplastic-to-thermoplastic, and thermoset-to-thermoplastic assemblies once both sides carry that weldable surface.

They have demonstrated an elemental aircraft-structure joint with strength equivalent to co-cured CFRP, named Boeing as a development partner & are targeting commercial airframe applications after 2030, which is a realistic timeline given the realities of qualification & certification.

𝗪𝗵𝘆 𝘁𝗵𝗶𝘀 𝗺𝗮𝘁𝘁𝗲𝗿𝘀

Thermosets still dominate aerospace primary structures because of mature supply chains, proven autoclave & out-of-autoclave routes, established design allowables. That is the reality we work with today. Thermoplastics bring welding, recyclability, shorter cycle times, post-formability, but until recently the bottleneck was how to integrate them into largely thermoset-based airframes.

The key question has not been which material is better, but how to join them reliably in one structure.

𝗪𝗮𝘆𝘀 𝘁𝗼 𝗷𝗼𝗶𝗻 𝘁𝗵𝗲𝗿𝗺𝗼𝘀𝗲𝘁 𝗮𝗻𝗱 𝘁𝗵𝗲𝗿𝗺𝗼𝗽𝗹𝗮𝘀𝘁𝗶𝗰

Adhesive bonding is well established but depends on strict surface preparation, cure cycles, quality control, with limited rate and repairability. Mechanical fastening is simple to qualify and inspect, but adds weight & stress concentrations. Co-curing or co-consolidation across thermoset and thermoplastic is rarely practical because cure and melt cycles do not align, so hybrid structures are typically joined after manufacture. Overmolding can work for local features, but is better suited to details than to large primary assemblies.

A weldable surface layer changes this picture, because it enables high-rate thermal welding even when one or both parts are thermoset, without adhesives or bolts.

𝗪𝗵𝗮𝘁 𝘁𝗵𝗶𝘀 𝘂𝗻𝗹𝗼𝗰𝗸𝘀

It means thermoplastics no longer have to wait for a clean-sheet programme. They can already be welded to existing thermoset structures, allowing designers to keep thermoset where maturity and qualification demand it, while introducing thermoplastic where welding speed, production rate, recyclability, or post-formability justify it.

Looking across many of the technical projects recognized this year at JEC, a clear pattern is emerging: thermoplastics are not replacing thermosets yet, but they are increasingly the technology that makes hybrid structures practical.

If you are working with mixed thermoset–thermoplastic structures, I would be interested to hear where welding already makes sense for you, and where the remaining qualification barriers still sit.

source : Fedor Antonov