3 AXIS Control Board (Complete)

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Gary Campbell
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CNC Control System Serial Number: Acorn 238
Location: Marquette, MI
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3 AXIS Control Board (Complete)

Post by Gary Campbell »

I have for sale an unused takeoff from a new machine that was upgraded to servos. Control backplane with all components mounted. DMA860H (8A) drives, 800W 75v stepper power supply, 120W 24v power supply, 3 each ~1200 ozin Steppers (only one shown), misc other components and all wiring as shown. Add an Acorn and you have a 3 axis "CNC in a box". This setup is perfect for a 3 axis mill or other high torque stepper applications

$200 plus shipping

gcnc411@gmail for more info or to purchase
IMG_20210830_133042215_HDR.jpg
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Dan Simons
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Re: 3 AXIS Control Board (Complete)

Post by Dan Simons »

Gary,
Would this be usable with an Acorn on a Shopbot PRT? You recommend motors in the 350-450 in oz range, and I believe the gearbox is 3.6:1? That gives total torque recommended as 1260 with a 350 in oz motor. These would be a little low at 1200 but wouldn't they work without a gearbox? Or would the number of steps be inadequate? I'm just in the learning phase, but my original PRT motors are I believe .5 degree per step, so with the reduction that would be 2592 steps per rotation of the gear, no? How would these compare? It's mostly hobby use for now, hopefully will find some things to produce in the future, but if I ever got to where it was heavy use I could justify changing it out again if needed. For now just want to get away from the old motors and controller.

Thanks,
Dan Simons
Gary Campbell
Posts: 1617
Joined: Sat Nov 18, 2017 2:32 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: Acorn 238
Location: Marquette, MI
Contact:

Re: 3 AXIS Control Board (Complete)

Post by Gary Campbell »

Dan...
I wouldn't recommend these motors for a PRT as they have way to much torque for the PRT frame and their weight hanging off the stock bracket will make the pinion run at more of an angle the the stock setup. These motors are 200 steps per rev, just like the OEM. And, just like the OEM, they should be run with gear reduction, never straight up.

I do recommend more reduction than the OEM setup, as 3.6:1 gears and a 25T pinion only gives ~.916 turns per inch, far below what anyone would recommend. The replacement setups I sold were ~1.59 turns per inch, IMO close to the bare minimum of what a good running machine requires
GCnC Control
CNC Control & Retrofits
https://www.youtube.com/user/Islaww1/videos
Dan Simons
Posts: 5
Joined: Sat Sep 11, 2021 8:19 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
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DC3IOB: No
CNC12: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: 3 AXIS Control Board (Complete)

Post by Dan Simons »

Thanks for the reply. For my own understanding, wouldn't a 350 in oz motor with a 3.6:1 reduction equal 1,260 in oz at the output shaft of the gearbox? That's what I thought was comparable to 1,200 in oz with no reduction. Heavier motor for sure, but with no gearbox I didn't know how much heavier overall, and the stock mounting brackets could certainly use an upgrade no matter what I do..

Also, my Vexta A6497-9412KTG motors say 0.5 degree per step on them, isn't that 720 steps/revolution? I was then taking that times the gear reduction to figure 2,592 motor steps per revolution of the output shaft on the gearbox?

I have a lot to learn.. :)
Gary Campbell
Posts: 1617
Joined: Sat Nov 18, 2017 2:32 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
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MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: Acorn 238
Location: Marquette, MI
Contact:

Re: 3 AXIS Control Board (Complete)

Post by Gary Campbell »

Like I said, do not run steppers without reduction.

Yes, you have 200 step per rev (native on the motor) times 3.6 = 720 steps per output shaft revolution
GCnC Control
CNC Control & Retrofits
https://www.youtube.com/user/Islaww1/videos
Dan Simons
Posts: 5
Joined: Sat Sep 11, 2021 8:19 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: 3 AXIS Control Board (Complete)

Post by Dan Simons »

I see, the original motors must have been supplied with the gearbox under that part number, so the 0.5 degrees per step already reflects the reduction.

I heard back from Matt after I had inquired with you about upgrades, but the current offering would be $4100+ which doesn't make sense for me at this time as I'm not making anything to sell, so I'm looking at other options for now.

Thanks,
Dan
Gary Campbell
Posts: 1617
Joined: Sat Nov 18, 2017 2:32 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: Acorn 238
Location: Marquette, MI
Contact:

Re: 3 AXIS Control Board (Complete)

Post by Gary Campbell »

Dan, et al...
If you can wait a couple weeks I will have an Acorn controller that has drives that are compatible with those high inductance dinosaur motors. Prices for the bare bones units start under $1700
GCnC Control
CNC Control & Retrofits
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Dan Simons
Posts: 5
Joined: Sat Sep 11, 2021 8:19 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: 3 AXIS Control Board (Complete)

Post by Dan Simons »

That's much more in line with what makes sense for me. Would those drives also work with newer motors if I upgraded them later?
Gary Campbell
Posts: 1617
Joined: Sat Nov 18, 2017 2:32 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: Acorn 238
Location: Marquette, MI
Contact:

Re: 3 AXIS Control Board (Complete)

Post by Gary Campbell »

Not very likely, as they are designed for low amperage, high inductance motors. Modern motors are higher amperage and low inductance.
You will have to choose between cheap or versatile.
GCnC Control
CNC Control & Retrofits
https://www.youtube.com/user/Islaww1/videos
Dan Simons
Posts: 5
Joined: Sat Sep 11, 2021 8:19 am
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: 3 AXIS Control Board (Complete)

Post by Dan Simons »

Gary, quick question as I research and try to learn. When you recommend 350-450 oz-in I was taking that as at the motor and then affected by the gearbox, but is that torque at the gearbox output?
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