Additive MAnufacturing Solution & Industrialisation for Next Generation InterMediate Compressor Case

Important results from the project

The project arose out of a series of discussions between GKN and Renishaw. GKN wished to investigate alternative additive manufacturing (AM) technologies for intermediate cases (IMC). One objective has been to develop and examine a higher-productivity process where multiple lasers are in use on a single part, examine laser focus settings and melt-pool stirring (MPS) build strategies to move towards GKN’s target of 3 kg/hr. Taking advantage of higher powder layer height and MPS build strategies, there would be a need of 6 lasers in an IMC production to meet GKN’s target.

Expected long term effects

Decreased total build of the IMC sector of Ti-6Al-4V from 58 hours 57 min in WP1 to 18 hours 50 min in WP4 by changing from single laser to 4 lasers, both using a layer height of 60µm. Increased bulk deposition rate of Ti-6Al-4V from 29.2 cc/hr/laser to 123 cc/hr/laser, an improvement of more than four times. Demonstrated that at high deposition rates, the Ti-6Al-4V tensile and fatigue properties meet or exceed those of cast material. Shown that melt-pool stirring is a processing technique capable of processing extremely thick layers at high deposition rates.

Approach and implementation

The start was to establish a baseline for the AM process, by maximising properties and quality at the expense of productivity and printed size. Comparison of tensile and LCF results with forged material data show that the results were comparable or superior. In the next work, the printing productivity was increased. By using four lasers simultaneously, the productivity increased approx. 3 times. The mechanical properties were found to be as good as before. In the next work, the productivity was further increased on behalf of that the test results were not as good and consistent as before.