Optimizing HVAC Brazing with Induction

Application: Brazing 

Industry: HVAC 

Application Objectives: A worldwide HVAC manufacturer is replacing old open torch technology with a new induction system to improve quality and reliability. 

The primary goal of this application is to build the process and to improve basic parameters for a more efficient and productive manufacturing cycle. The team aimed to reconfirm the brazing process during customer`s visit and to conduct additional tests using lab coils to optimize the brazing cycle. This involved ensuring that the new process could meet the stringent requirements of the HVAC industry, particularly in terms of quality and efficiency.  

Equipment:  

• Power Supply Models: Solo24, SM5 

• Heat Station Models: HS24W, HS-4W 

• Test Coils: UltraFlex Lab Coils 

Materials:  

• Copper and brass HVAC assemblies, from 15 mm to 85 mm in diameter. Copper pipe count varies on the assembly. 

• Silver brazing alloy (40%) and flux 

Key Parameters:  

• Time: Heat cycle times varied from 15s to 40s. 

• Power: 5kW to 16kW 

Process:  

The process began with the preparation of brass assemblies, which varied in diameter from 15 mm to 85 mm. These assemblies were composed of copper and brass, and the team used a silver brazing alloy (40%) along with flux from the lab. The assemblies were then subjected to a series of heating tests using different power supplies and heat stations, including the Solo24 and SM5 models, paired with HS24W and HS-4W heat stations. 

During the tests, the team meticulously monitored the heat cycle times, which ranged from 15 to 40 seconds, and adjusted the power settings between 5kW and 16kW. The frequency of the tests varied from 112kHz to 130kHz. Each test was carefully documented to determine the optimal settings for achieving the best brazing results. The team also focused on optimizing the temperature distribution and ensuring that the process could be controlled effectively. 

Results and Conclusions:  

The results of the tests were promising. The team successfully brazed the assemblies using both the 5kW and 24kW systems. Notably, the Solo24 system allowed faster heating cycles, which provided better control over the process. This was a significant improvement, as it enabled the team to fine-tune the brazing process more precisely. 

The tests also highlighted the importance of coil optimization to accommodate the various part sizes. The team recommended discussing the proper ring dimensions with the alloy manufacturer to ensure compatibility and efficiency. Additionally, integrating the flux into the rings was suggested to simplify the application process.  

Overall, the application tests confirmed that the new brazing technology could meet the desired quality and reliability standards. The optimized process not only improved the heating cycle times but also provided better control, making it a viable replacement for the existing technology. 

Reference Info: AR 3464-7300