I recently put steppers on my cross slide using the BlackBox. I was showing a fellow worker a video of my working CNC and he told me his uncle had a CNC for sale. I wasn't holding out much hope of getting it when he told me it has not ran for years and he wanted 250.00 dollars for it. I was thinking tape machine. To my surprise it was a mid 90s bridgeport with a milltronics control, that came with 30 ntbm30 tool holders. I bought the machine within 5min of seeing it and I only had 20s so I couldn't come up with the 250 so the nice man said just make it 240. I got the mill to power on but when I try to home it I get a 404 error code and the x axis never resets I was able to fake home and get Z and Y to jog but X will not move I am using a 3hp 30amp cederburg roto phase and when I try to start the spindle it starts spinning but quickly stops when the controller re-boots. (I think I need a bigger converter) GA370-3 DRIVERS MT30M4-38 FERRITE BRUSHED DC MOTORS FOR X-Y MT30U4-42 FERRITE BRUSHED DC MOTORS FOR Z CENTURION V CONTROLS Now to my questions If I cannot get the current system to work, what would be the best method to upgrade? Does openbuilds have a system that would provide enough power to run theses motors?
It'll probably have old brushed servos. You can still buy them if the X axis needs replacing, but I don't know if it's worth trying to get them working or not. Maybe. Depends how much you want to play with tweaking driver PID loops for speed and stability, really. You'll have to look up the error code for the control, presumably it's related to the X axis driver- sometimes it's as simple as "the driver alarm wire that tells me it's not errored is disconnected" though, worth poking in the wiring. If you go with the easier option of steppers, it'll need at least NEMA 34s, probably 8Nm or 12Nm since it's oil ways, maybe even a NEMA 42 on Z, no chance of using the BlackBox- they're all 5A+. I'd use closed-loop steppers because they come with the drivers, you usually just have to supply 48-72VDC power (I actually have a 120VAC driver for my 12Nm stepper on Z). You wouldn't need 3ph to the control this way either, just the spindle. There's a pretty high chance you'll have to change out the screws, whatever they are, maybe you'll get lucky but lash may still be an issue regardless. With the travels available on a BP, I'd convert to linear rail and attempt to keep the servos (or switch to AC brushless servos) for high-speed VMC type operation. They're not so incredibly rigid that it'd be inherently worth keeping it on its ways (assuming they're actually in decent condition, which they may not be- "clapped-out Bridgeport" is an expression for a reason, though tends to refer more to earlier manual machines). Then I'd see if there's a spindle cartridge available for petal clamping (I'd guess probably) and switch to BT30 tool holders with an air cylinder. I'd convert to LinuxCNC regardless, personally, old controls are usually more trouble than they're worth unless you can get support for it like maybe an older Haas control or something.
Thanks for the quick reply I have been working in Toolroom machine shops my whole adult life , running all kind of equipment like Hass, Fanuc, Analam Prototrak, Fadal This machine is far from being clapped out. I have checked the backlash on Y&Z Y has less then .002 and Z has .0025 both well within whatever I will be machining at home. If I need more precision I will do it at work.
Sounds like a screaming deal to me. If you don't want more than basic 3-axis operation, no toolchanging, fairly low speeds, no backlash comp, wear comp, etc then you could probably use grbl just fine instead of LinuxCNC if you needed to change control. Should work ok with the existing servo drivers if you can make them all work with step/dir operation. If they're analog or serial or whatever only, that wouldn't be an option unless Mesa or someone makes a step/dir interface card. And steppers would be the easiest/fastest/cheapest upgrade method if you do need to dump them, you'd just lose some high-speed torque.
Rocky, you paid only $240 for that machine!!! If you take it to a recycling center you'll get more money for just the metal and that is after you took the 3hp motor off and sold it for some extra cash. Great find!
Yes, I also couldn’t believe it. The only problem I have now, is that a week earlier I bought a powermatic vertical mill and I’m now low on cash to get this up and running.
