Impact Innovations presents the CSAM of propulsion system components »3dpbm


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New commercial rocket engines require fast and inexpensive AM processes that provide sufficient flexibility to respond to changing demand for launches. For these reasons, in recent years special attention has been paid to AM processes and developments, in particular powder bed fusion AM due to its freedom of design and prevalence in the market. . However, AM powder bed fusion techniques face challenges limiting the use and scalability for the fabrication of the combustion chamber, such as the limited dimensions of the building envelope; limited processing of metals and alloys, including multi-material layers; and high surface roughness, especially in the inner walls of cooling channels, which can greatly reduce the cooling efficiency.

The Cold Spray Additive Manufacturing (CSAM) process, developed by Impact Innovations, has the potential to overcome all limitations and offers a potential solution to fabricate combustion chambers with superior properties and no envelope size restrictions. Impact Innovations has set up a collaborative project with Airborne Engineering (AEL), a British company specializing in the design and testing of propulsion systems. AEL designed a combustion chamber demonstrator according to Impact Innovations guidelines. The regeneration cooled liner is high strength Cu alloy and the outer jacket material is Inconel.

The demonstration sample proved that the CSAM process is suitable for the manufacture of combustion chambers and many advantages over other additive manufacturing processes were identified: no protective atmosphere required, the simple assembly technique of dissimilar materials / alloys, negligible thermal stress, no cooling channel surface roughness issues, access for inspection during production stages, ability to rework / repair areas for prototypes and join additional parts without welding; and powder is only needed for the material to be deposited, rather than in AM powder bed melting processes where it is needed to fill the entire build volume. Buy / steal ratio close to 1.

To demonstrate the dimensional flexibility of the process at Impact Innovations’ spray lab, the spray lathe allows the fabrication of components up to Φ1500mm in diameter, 2000mm in length at a maximum component weight of 1500kg. A full-size combustion chamber, as shown in Image 2, is being manufactured at Impact Innovations and will soon be available for fire testing at the AEL site.

The mechanical properties of combustion chambers are very critical and depend on the materials used. A special cooling channel demonstration sample was fabricated to determine the mechanical properties of high strength Cualloy and Inconel. The resulting mechanical properties are shown in the graphs: as deposited, after heat treatment at room temperature and elevated temperature (427 ° C).

The second important aspect is the deposit rate which has a significant effect on costs. The CSAM process developed by Impact Innovations has a deposition rate of 10 kg / h for the Cu alloy and 6.7 kg / h for Inconel, which is more than 20 times faster than the AM fusion processes. on powder bed.


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