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Innovative laser technology restores the iconic Spitfire

Aircraft Restoration Company (ARC) and TWI joined forces recently in an effort to repair a second world war Spitfire when a crack was detected in a landing gear suspension link during restoration. TWI experts recommended using high power laser metal deposition, enabling the restoration team to build a crack free repair in the landing gear component.

During restoration of a WW2 Spitfire aircraft at Duxford Aerodrome, Cambridgeshire, ARC detected a crack in a landing gear suspension link. The company approached TWI to see if it could provide a process to repair the cracked area. It was essential that any successful repair would have minimum effect on the properties of the original component material.

The project team based at TWI’s Technology Centre in South Yorkshire suggested an innovative repair process employing a high power laser beam and metal powders. The Laser Metal Deposition (LMD) process has the low heat input needed to produce a high quality repair. In LMD, a focused laser beam creates a small melt pool on the surface of a component and metal powder is fed into the pool to create a metal deposit.

ARC provided TWI with a scrap part made from the same material as the part to be repaired. The team used this part to develop laser deposition parameters for the repair.

NDT image showing extent of crack on aircraft undercarriage component
NDT image showing extent of crack on aircraft undercarriage component
Trial fit of sleeve pressed into bore prior to machining of cracked area
Trial fit of sleeve pressed into bore prior to machining of cracked area
Cylindrical tubular sleeve being manufactured using laser deposition
Cylindrical tubular sleeve being manufactured using laser deposition
Completed repair after deposition and machining away of internal sleeve
Completed repair after deposition and machining away of internal sleeve

The landing gear link was originally manufactured from a material grade, now obsolete. TWI identified a current high tensile steel which closely matched the original for composition and material properties but crucially was also commercially available as a metal powder. TWI used this powder for the deposition and repair work.

The specialist team carried out the repair, making quality checks at each stage before going forward to the next; the process beginning with the determination of the full extent of the cracking by non-destructively testing the area around the visible crack. The team determined the extent of the crack and machined away the defective material.

Work was carried out using the Trumpf DMD 505 laser deposition machine at TWI. By varying machine settings such as laser power, deposition speed, laser spot size and powder flow rate, it was possible to determine a combination of parameters that produced a defect free deposit and a strong fusion bond with the component. This was validated by sectioning and inspecting the microstructure of the deposited material produced on the sample supplied by ARC.

The team then manufactured a cylindrical tubular sleeve using the laser deposition machine and the selected powder. The manufactured sleeve was press fitted into the bore of the suspension link and formed a base for further laser deposition workto fill the gap produced by the removal of the cracked material.

Using deposition parameters determined previously, TWI used laser deposition to replace the material removed by machining. The laser deposited material fused onto the internal sleeve and onto the sides of the machined recess, ensuring that the sleeve was securely fusion bonded to the original material at the edges of the repair.

The internal sleeve was then removed by machining but without touching the original bore diameter. This left a crack free repair of the landing gear component.

Please email contactus@twi.co.uk for further information or investigate laser processing and laser metal deposition at TWI.

Cylindrical tubular sleeve being manufactured using laser deposition
Cylindrical tubular sleeve being manufactured using laser deposition

For more information please email:


contactus@twi.co.uk