Step 24: Stepper Driver Completion
This tutorial is dated, if you are considering a CNC for your personal use, we would highly recommend purchasing a kit that is very stable from our wide range of machines available
We are finally at the end of the driver assembly. This video also shows the most important part of the stepper driver assembly. In this step, you will solder in the driver chips, the heart of the board. You will also clean, inspect and set the board's configuration.
The driver chips are the most important part of the board. They handle most of the operation for the stepper motors. It is very important to read all of the instructions and do exactly what it says. I can't emphasize this enough. The driver chips are sensitive to the motor connections. If the stepper wires are not correctly connected, or they are pulled out while there is still power in the circuit, the chips will blow. Furthermore, don't touch the stepper motor wires for more than three minutes the power is shut off. Capacitors on the board and in the power supply are bled very slowly. A multimeter will corroborate this characteristic at the TB6 terminals.
Clean the board thoroughly to see if there are any solder bridges. What you are really cleaning is flux residue that build up between soldered leads, so you will need a brush or something that can get into those tight spaces. It's amazing how clear this process makes the board. After the board is cleaned, inspect the board with a magnifying glass. Some individuals have mentioned that both sides of the board will need inspection since the solder can seep through the holes and build up on the other side.
The three axes will have a potentiometer to control the current for the motor amperage. The instructions explain the correct setting for these. Oh yeah, a potentiometer is a variable resistor, or a resistor that can be controlled via a dial, or screwdriver. A volume control on a stereo is a good example. Although, a dial for a stereo tuner is not a potentiometer, but that explanation is for another day. The kind folks at HobbyCNC.com mentioned that to reduce heat gain, set Vref (the potentiometers) at 70% of the required amount.
So now that we have completed the stepper motor driver, what do we do next? we need to make a power source for the driver. I was using a laptop power supply for the tests, but a much more powerful power supply will be needed. The stepper motors will also need to be connected to the stepper driver. Then we will get into the various router/dremel mounts and ways to suck up that terrible dust created from the cutting tool. That is unless you are installing an extruder, laser or heater.