Step 29: Heat Sink and Driver Connections
Yes, we've used heat shrink, but now it's time for a heat sink. No, it's not a hot tub. A heat sink is usually a piece of metal that allows something that gets hot to dissipate the heat. It is advised for the three driver chips on the HobbyCNC board. The installation is straight forward. Holes are marked and then drilled. It is important to note that the drill will create many metal shavings. Metal shavings are incompatible to the proper functioning of the driver board. If any of those shavings get on the board, you will risk a blown chip. Before final installation of the heat sink, a white compound should be spread between the component and the metal, like a peanut butter sandwich.
In the video, you will also see the insertion of the motor wires into the driver. Very important, the motor wires must be connected while there is no power to the board at all. "At all" means, .01 volts, that when you power off the power supply, the capacitors are insuring that there is still power to the board, and the capacitors take time to release all of their energy. It is recommended to wait at least 3 minutes after powering down the supply before connecting or disconnecting the motor wires from the driver board.
Also in this video, you will see a test of the machine. You will get a glimpse of the software that I use (explained in a later post). I run a g-code program (interpreted by EMC2) to determine if all of the motors are functioning correctly. G-code is a language that tells the CNC what to do. If a very simple language that nobody ever wants to learn. EMC2 is a software application that takes g-code, interprets the code into step and direction signals and sends them to the driver board. Don't worry, I will explain this in much greater detail in a later point, including a tutorial on the g-code language, and cheap CAD/CAM techniques.