Originally Posted by
mitip
Thanks guys, I am trying to understand the differences between what we used to do and what these benchtop machines can do. We used to post as Fanuc, so that is OK. Also I read that steppers are nearly as accurate as servos, but you are suggesting a servo set up would be better?
You make a point about the accuracy of the machine needed, I am not clear how rigid these smaller machines are or whether it is worth considering an older machine and doing a refit. I came across a machine that is half way between a Bridgeport knee mill and a benchtop, very solid cast construction, I could scrape the slides and get it working well but would there be any benefit? All the parts are heavy, especially in z, would the torque needed be too much for steppers?
Last point, I gather with Mach3 the data drip fed to the controller via parallel, is the point you are making that this is not a limiting factor? I recall early Interact controllers that would simply stop and dwell when they ran out of data. You mention 1000 lines look ahead, which I recall was a figure from the past, is this OK when doing high feed rates. I have a brand new NSK 65,000rpm air head worth about $4000 I was planning to use but it does not have much torque but should be OK with 1-1.5mm cutters although someone mentioned electronic heads that are OK for 36,000rpm. One of the guys who did our programming never used more than 20,000rpm but for plastics I found the faster the better as long as you can get the heat and swarf away and stop burning. What is the emc2?
Mike