For a long time I've been contemplating somehow acquiring a CNC machine as a tool to compliment my hobbies and also to further my education of CNC manufacturing. I've worked with CNC programming and machining as part of my job all my life. To be able to configure and build a machine using the type of components OpenBuilds offers is for the most part perfect for my needs. However I would like to have a CNC controlled variable speed spindle rather than a woodworking type router. I am having difficulty finding information for putting together a machine with that type of spindle. I looked around on this forum to see if i could find anything and i am just not seeing it. Can anyone help?
Pretty much all of the controllers (Mach3, LinuxCNC, PlanetCNC, TinyG, GRBL, Smoothie, etc) have a PWM motor speed control pin output. On most of them this a 5v TTL signal. M3Sxxx sets the PWM value, usually 255 steps of resolution M5 turns it off some controllers also have a direction pin and M3/M4 will control that as well. So, all you need is a spindle that can take a TTL PWM input and connect it up (-: for example https://www.amazon.com/12000rpm-Brushless-Spindle-Motor-Controller/dp/B00S8B8CIU
There are AC and DC spindle motors. DC spindles(google quietcut spindle) are easy to hook up and run. They are powered by a DC power supply, are fan cooled, and controlled by a motor controller as Dave pointed out. AC spindles (chinese spindles) are more expensive and complicated. They are heavier, require a capable AC VFD, more consideration for the electrical supply available, and come in fan or water cooled varations. The VFD controls the speed and distributes the power from the wall to the motor. (Tip: If you're using an uncommon VFD like I did then setup is pretty much on you to figure out. My VFD manual was around 600pages to sort through and I still had to hit up the nets electricians.) Both systems can be turned on and off directly or remotely. There's a lot of variables in deciding which is best for you. If you want production, precision, and efficiency then an AC spindle is for you. If you're on a tight budget, want to be up and running asap, and have plenty of time for a job to complete then DC might be the route for you. We have both AC and DC spindle users here on the forums and the net is getting full of them as well at this point. Joe
