Key Takeaways
- Inconel 718 heat exchanger printed by DMLS for defence electronics.
- Consolidated multiple parts into one, removing joints.
- Withstands high temperature and pressure.
- Showcases superalloy additive for extreme environments.
Industry: Defence Electronics | Process: DMLS (Inconel 718) | Volume: 4 prototypes | Lead time: 9 days
The Challenge
A Hyderabad-based defence electronics OEM was developing a next-generation radar processing unit with a thermal power dissipation of 1.8 kW in a 220×160×80 mm footprint — demanding heat flux management that conventional cold plate designs could not achieve. The system operates in a sealed military enclosure with no active cooling; all heat must be conducted to the chassis.
The thermal design team specified a distributed mini-channel heat exchanger with 0.8 mm internal channels, a conformal base that mates precisely to the PCB hot spots, and Inconel 718 for its thermal properties at elevated temperatures and compatibility with the MIL-SPEC environmental qualification. The conventional route — EDM wire machining and diffusion brazing of the channels — required a 14-week lead time from a specialised heat exchanger manufacturer at ₹2.4 lakh per prototype.
The programme timeline allowed 3 weeks for prototype evaluation. Four prototypes were needed for parallel testing in different boundary conditions. Conventional manufacturing could not deliver in time at any commercially realistic cost.
Our Solution
DMLS Inconel 718 is uniquely suited to this application. The process builds internal channels during the print without requiring access from the outside — channels as small as 0.4 mm diameter are achievable in current-generation machines. Layer X printed the complete heat exchanger as a monolithic part: base plate, channel network, and manifold headers in a single build, eliminating the brazed joints that are the typical failure mode of conventional heat exchangers.
The channel geometry was designed by the customer''s thermal team (they provided STEP) and reviewed by Layer X for minimum feature size and powder evacuation. The smallest channel cross-section was 0.9×0.9 mm — confirmed achievable with full powder clearance through the open manifold ends.
Build was performed in 316L first for geometry verification (delivered in 48 hours), then Inconel 718 for the four qualification prototypes. Post-processing: bead blast, CNC facing of the base plate and PCB contact pad, and helium leak test at 3 bar to verify channel integrity.
Results
| Metric | Conventional EDM/Brazing | Layer X DMLS Inconel |
| Lead time (4 prototypes) | 14 weeks | 9 days |
| Cost per prototype | ₹2,40,000 | ₹68,000 |
| Brazed joints | 24 per unit | 0 (monolithic) |
| Thermal resistance | 0.14 °C/W | 0.09 °C/W (−36%) |
| Leak test (3 bar He) | Pass (3/4 units) | Pass (4/4 units) |
The 36% improvement in thermal resistance came from the DMLS geometry''s ability to pack channels with tighter pitch and conformal routing than EDM constraints allow. The monolithic Inconel construction eliminated all brazed joints — a reliability improvement critical for the 15-year service life requirement of the radar system.
All four prototypes passed the MIL-STD-810H vibration and shock profile without channel fracture. The programme director confirmed that the programme timeline was preserved entirely due to the additive manufacturing route, and that design features were enhanced — not compromised — by the switch.
The customer is now qualifying Layer X as a production supplier for the first batch of 24 units.