ShopBot (arcs)(inch)(*.sbp) versus ShopBot Arc (inch) w/speed (*.sbp)

[carolinasmith]

(Aspire 8.5): Can someone please explain when one would want the post processor 'w/speed' versus the one without? Seems like there would be a difference else why are there two choices? Thank you.

[steve_g]

If you have a spindle that allows speed control within the program code, use the “with speed” version… the speeds you specify in your bit definitions will apply. None of the PC routers qualify…
SG

[carolinasmith]

Thank you, Steve, that sounds great! I do have a spindle (Desktop MAX) with speed control (a box with knob control that I have only used when warming up the spindle), but until I learn more, I have just used the default settings that seem to populate the fields when I choose a bit. Sounds like I will be using the 'w/speed' post processor from now on. When I just used arc inches, was it ignoring the speed in the bit definitions? Many thanks.

[steve_g]

Carolina…
Someone with A desktop MAX will have to chime in here… Just because you can manually change the speed with a knob, doesn’t necessarily mean that the spindle is communicating with the computer… I don’t know if the MAX does.
SG

[scottp55]

If it's like the Desktop Carolina, then we have to manually adjust the VFD.
Tech told me once that the Desktop controller and the VFD don't speak the same language.
But that was Desktop, and 2 yrs ago.
Easy enough to make a test file with 2 different RPMs and save using each to see if you can hear the difference?
scott

[carolinasmith]

That sounds like a good test plan to try, thanks

[tlempicke]

If you have spindle control of speed from the SB3 program you have to have a small circuit board installed in your VFD. That circuit board has a USB plug that plugs into the control computer.

[carolinasmith]

If you have spindle control of speed from the SB3 program you have to have a small circuit board installed in your VFD. That circuit board has a USB plug that plugs into the control computer.

Thank you, I partially understand, I think. I can't look at my D Max for a few days. Pardon my ignorance, is the control computer part of the CNC innards (housed at one end of the machine), so look for a USB plug from the VFD to there? Or is the control computer my laptop and I would plug in there? Guessing inside the CNC innards. Sorry!

[tlempicke]

In mine the circuit board is inside the VFD and a second USB plus goes to the control computer.

[scottp55]

Control Computer would be your laptop Carolina.

[carolinasmith]

OK, thanks. I'll look this weekend. The reason I asked was because I recalled an Andrew Pitts's YT video:
https://www.youtube.com/watch?v=3iwKFDER494

where he discusses and shows how he get's into his Desktop's control board (which also has a controller card with USB port) for
a problem he had. Thank you for the clarification. I'm thinking there was a VFD manual in all the packings, so I'll check further.

[steve_g]

Carolina…

Control board, control card and control computer… three different things!

The control board is where everything plugs into, including the control card! The control card is a “daughter” PCB with an edge connector that plugs into a socket on the control board. Current control cards (like yours) have a USB socket on them where a USB cord plugs into it and goes to the control computer, a windows OS laptop or desktop that you provide.

I read what I could readily find on the SB web site regarding the DT MAX and could find no reference to it having spindle speed control. Also, the speed control board poop sheet says…

“The Spindle Control Board is compatible only with ShopBot alpha and V4G boards using SB control software v3.5.6 or greater.”

So… near as I can tell, you don’t have automatic speed control set by the software. Actually this makes sense, the main purpose (in my mind) of auto speed changing is so that machines with ATC (automatic tool change) can change bits unattended and have the spindle change speed automatically, to match the new tool. That said, I sure like it on our PRS for mindless warmup procedures!

Hope I haven’t confused the issue!
SG

[carolinasmith]

Thanks for a lucid explanation, that was great and I appreciate everyone's time.