SMT constant temperature desoldering station

1. Project description

        A DIY constant temperature desoldering station, the main control is STM32F103C6T6A, max6675 cooperates with K-type thermocouple to read the temperature of the heating station, PWM output to the optocoupler to control the output power of the triac, and PID temperature control.

        The temperature is adjustable from 100 to 230. The upper limit of the temperature depends on the power of the heating table. The highest temperature I have can only reach 230. The heating takes less than 1 minute, which is okay.

        I have attached the component list and project source code. The PID adjustment is not very good, so you can adjust it yourself. The pin header, power cord and PTC heating plate are missing from the component list. The power cord can be two-core or three-core, as long as the wire length is not too short. Search a lot of them on the heating platform, and the total cost is about 50 yuan.

        Additional explanation: The sampling rate of max6675 is very low. If the cycle is set to a smaller value, the data cannot be read. In the test, the fastest reading time is about 200ms. This is also one of the reasons for the inaccurate PID...

2. Production process

        The whole project is relatively simple. Just solder all the components directly. Remember to put some tin on the window opening part. There is nothing else to pay attention to. After everything is soldered, use copper pillars to connect an empty board underneath. The thermocouple needs to be disposed of. Remove the screws and metal protective shell of the temperature measuring head. Apply thermal conductive glue and high-temperature tape to the back of the heating table. Just straighten the wires. Note that the red interface is connected to T+ and the blue interface is connected to T-. There are two wires on the heating table in no particular order, just connect them casually. Connect the 2Pin AC-N and OUT-L.

        Since the temperature of the heating table is still quite high, I arranged four wooden sticks ( about 4cm high ) and connected them underneath for heat insulation. Next is the casing. It’s low-cost and can be made directly from the prototype PCB box. Stick foam glue ( hot melt glue is best ) at a similar position on the bottom , put the main control and heating table in, fix it, then make a hole on the left side of the power interface, plug the wire in, and connect the 3Pin socket Connect the power cord. Be sure not to connect the zero and live wires incorrectly here. Then the box won't close. Just cut off the stuck part of the box, so that it can be closed to prevent dust. Remember to put some electrical tape on the terminal blocks to prevent your hands from touching them.

        That’s it. Plug it in, turn it on, light it up successfully, and then press it briefly to start heating.

 I recorded a demonstration video, but it's too big to upload...

When it comes to 220V mains power, you must pay attention to electricity safety when DIYing! ! !