So much for the current status of the CNC milling machine. I have made some first experiments with L297/298 motor drivers and found out the hard way that these are quite overloaded with such strong motors. Burnt out in a matter of seconds. But, as BJT driver bridges are not state of the art anyways, and I want to take a lesson from this project, I decided to finally get myself some of those specialized ATMEL controllers (AT90PWM1) and try to design my own FET bridge driver.
I even have one in spare that I can use for experiments with a self-designed high intensity discharge lamp driver – I have attached an image of an early prototype to the gallery for your entertainment. Worked quite well for some time, but the driving was very crude – there are some logic gates on the bottom of that small pcb that generate half-bridge signals for the two FETs, but no care taken about anti-shoot-through and so on. VERY crude. I will report how well the new controllers work out, seeing that very few experiences are found 🙂
As for the CNC, I am quite confident that I will finish the mechanics part within the next holidays (around easter). Then, all that remains is the ‘intelligent’ part.
Last but not least, I notice that I still do not manage to describe my projects in my self-desired level of detail. Thus I will focus more on taking pictures during the process and explaining from now on.