Bridgeport Manual to CNC conversion...

[Davek0974]

Thanks JAZZ,

The UC300 USB motion controller goes to 100kHz so that seems ok, I only suggest that one because I have used the smaller UC100 with total success and the price is pretty good too. However I do not know yet if that interfaces direct with the servo drive unit?

Not having a high power PSU is a big plus as well and as there is no price difference it looks like servos have won the toss :)

Would you go with 750W motors or smaller??

2:1 reduction for resolution & torque increase, more?

Servo drives seem to have lots of settings, what is used - speed & torque, positioning..... All new to me but i have the manual for the drives now.

[JAZZCNC]

The UC300 USB motion controller goes to 100kHz so that seems ok, I only suggest that one because I have used the smaller UC100 with total success and the price is pretty good too. However I do not know yet if that interfaces direct with the servo drive unit?

Well not really 100khz is still 400khz short of full speed/res. Or 1:5 multiplier so only getting 5th of resolution. Plus it's USB rather than ethernet so wouldn't be my first choice.
Really Ethernet Smooth stepper is what you want or feeling really flush then go for Cslabs Controller.

Would you go with 750W motors or smaller??

Probably 750W but really you should do some calcs to get better idea of size, inertia ratio etc. Like steppers Bigger isn't always better.

2:1 reduction for resolution & torque increase, more?

Again depends on other things like screw pitch and what kind of speed/res/torque your looking for. Thou 2:1 with 5 or 4mm pitch screw sounds about right. My Big Semco CNC Mill uses 5mm pitch with 2:1 ratio and 1.8Kw servo's but it Dwarfs BP.
Matt (kingcreaky) on the Forum used 750W servos with 2:1 ratio on BP Interact sized mill and was happy with them. (He's got a video some where on this site)

Servo drives seem to have lots of settings, what is used - speed & torque, positioning..... All new to me but i have the manual for the drives now.

If using Step Direction then you use Positioning. If using Analog +/-10v control then would use Speed. You'll be using Step & Dir so positioning.

Difference between Step/Dir and Analog is mostly how they are controlled and how the Closed loop works. With S/D the loop is closed only between drive and Motor. Analog the Loop is extended between Controller drive and Motor.
The result is that Analog feeds the Encoder position back to the controller, which it must do to work, which then checks this position with the commanded position and if wrong sends corrective signals.
The upshot is that the DRO's always display the actual position of the table, no matter if mach or controller as commanded this or you whind it there by hand. In affect works just like Manual DRO's.

Step/Dir on the other don't do this. It sends commanded position to the drives and takes it on faith that it arrived there. The drive then takes control of getting to commanded position and any corrections needed.
So the DRO's only show the commanded position and if it's wrong or if for instance something is loose you'll never know your out of position. Essentially works just like your steppers now with the exception the drive is checking the motor actually moved the distance told.

Bottom line is S/D is easier to setup. Analog gives more feed back but takes more setting up and tuning of drives.

See this video I made showing 1.8Kw servos controlled via Analog.

[Davek0974]

Nice video, that would be what i would like ideally - feedback.

So The option is now ESS at about £150 and no feedback or CSMIO/A at about £490 with all the bells and whistles.

The motors I was looking at are from the same guy as in your video, drives the same too.

The 750W suggestion comes from the CNCZone where a builder mentions doing 30+ conversions of this type and always uses 750W, 1kw was too large and 400W too small.

He uses 1:1 or 2:1 but I favour 2:1 as I want to get the most torque I can and the machine won't handle massive rapids.

Ballscrew kits seem to be 5tpi so 5.08mm pitch

Question is - is the benefit of real-time position DRO worth the extra cash?

[JAZZCNC]

Question is - is the benefit of real-time position DRO worth the extra cash?

Yes IMO but with the Cslabs controller there's more to it than just this. You also have very accurate Homing using the Index pulse of the Encoder. You can also Fit a Servo to the Spindle and control that just like an axis so can index to position or do things like ridged tapping etc.

Then you have 24V I/O etc not to mention you don't need a BOB. This Alone is BIG Plus, esp when using servo's. Don't confuse the IP-S with ESS they are completely differant animals.
While they seem expensive they are not actually that bad when you consider that it's one complete unit nothing else is required. It's also Industrial spec and high quality.
By the Time you have Bought ESS and Decent quality BOB like PMDX126, which about the only one I'd use with servo's plus Spindle speed Control board then your not long way behind the IP-S or IP-A.
They really do not compare other than both use Ethernet and provide 4Mhz after that it's all down hill for the ESS.!!

The motors I was looking at are from the same guy as in your video, drives the same too.

Think you'll find 750W will be most likely be 80 frame(like Nema34) not 110 which will probably be better for you. Drives may be smaller too.?

[Davek0974]

Ok JAZZ, i'm sold on the CSMIO/A unit, does it have PWM output or is that an add-on? Controlling the VFD would be nice.

Will be reading up on that tonight.

Rigid tapping is a bugger because you need to get an encoder on the spindle - this is a nightmare the Bridgeport manual machines. Possible later add-on though.

Yes I think those motors will be Nema34 size.

[JAZZCNC]

Ok JAZZ, i'm sold on the CSMIO/A unit, does it have PWM output or is that an add-on? Controlling the VFD would be nice.

Yes it as Analog 0-10V Output for spindle Control built into it. Also has few Analog Inputs so can use Pot to override spindle speed and feedrate if desired.

[m_c]

A couple things to remember with the CS-Lab controllers, is if you want rigid tapping, you need to add the ENC/threading module, although not really an issue if you're happy to use a tapping head or thread mill.
Also, if you want to add a MPG, you need to buy the MPG module.
I would of suggested a KFlop+Kanalog (+ a Konnect if you need more than 8 In or 16 Out) as they'll do whatever you program them to do without any additional modules, however you need to know at least a little bit about C programming to get them working.

I was advised for my big mill, that the larger motors would be a better match. I was looking at 1000W 80 frame motors, and 1050W 110 frame motors, although I think I'll have to get 1200W to get the 3000RPM now. However I do think you could probably get away with the smaller frame motors on a standard Bridgeport, as it's not that heavy a table.