Induction Soldering of Brass Valve and Copper Tubing

Objective: An agriculture tool manufacturer is looking to implement induction soldering in the production of their tools. Currently, they use gas for soldering but want to move to induction heating so that they can improve their quality, repeatability, and working conditions.

The parts that we have to solder are copper tubing to a brass valve. The temperature should not exceed 280°C in the middle of the parts. The customer wants to increase productivity to 50 pieces a day.

Industry: Manufacturing & Automation

Equipment: We used UltraHeat SM – 5kW Induction Heater and it is the suitable machine solution for this application.

Process: Two power supplies were considered for this application. 5kW and 2kW. The benefit of the 2kW is a lower price. The trade-off is the need for a high inductance coil which will allow for better efficiency. A higher inductance coil may not work best since it obstructs the working area and may come in contact with the part. It was tested to offer the customer an alternative to the more expensive option. Even then, it was noted that 2kW does not offer the same flexibility and heat concentration compared to a higher power unit. The 5kW, although being more expensive, is superior in performance, being able to work with a two-turn coil which allows for better heat concentration and shorter heating cycles. It was demonstrated to the customer that the system can achieve excellent soldering joints with solder flowing upwards or downwards confirming that the orientation of the workpiece can be altered to fit the customer’s needs.

The test with a 5 kW power supply took 11 seconds to achieve excellent flow at 280°C. The second and the third tests we conducted by detuning the power to 2 kW and using two types of coils. With these changes, the cycle time was increased to 38 seconds for a two-turn coil and 16 seconds for a six-turn coil.

Benefits: For the best results, a 5-kW unit with a two-turn coil should be used. It is a better choice overall despite the higher cost.

The implementation of induction heating in this process will increase productivity, optimize the process, allow for easier automation, and save production time and energy.

Reference Info: Application Note 3463-7096.

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