Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

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jhenise
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CNC Control System Serial Number: kit 103591 CNC12 SN XBBHIDEBGBC

Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by jhenise »

I am starting a thread here about setting up the Centroid Oak Control on a brand new bed mill that I recently acquired.

The mill is a Taiwanese CNC ready frame (basically a mill lacking a control and servos) and was imported and purchased from HS&S Machine Tool in San Jose CA. I am very happy with the appearance of the machine it definitely has that Taiwanese niceness and not the dreaded Chinese cheapness.

machine specs:
It is a box way machine. Box ways on the Y and Z at least, and dovetail ways on the X axis. The table measures 14" x 50". Travels are: X = 32", Y = 16", Z = 17" and the head is counter-weighted. Spindle to column distance = 16", Spindle to table distance = 4" - 20". I got an upgrade 8000 RPM BT40 spindle with an oil chiller, and a 16 position umbrella ATC. The spindle motor is 7.5 HP with a 1024 count/turn quadrature line driver encoder (A,B, and Z) where the Z pulse is 1/rev for tool change indexing and starting rigid tapping cycles. The motor is geared to the spindle 1:1 with a genuine Gates PowerGrip (GT3) 8mm pitch 30mm wide belt. The machine also comes equip with the draw bar pneumatic actuator, lube pump, limit switches, air solenoids, coolant pump/sump, work light, metal way covers, and metal splash shields. The ball screws are 0.2" / rev pitch, C3 grade, double nut.

One of the main reasons I liked this machine was because it has the smallest overall size I could find for something with a work envelope this big. So that made it easy to get into my San Francisco garage! Also building the control will allow me to locate the electronics cabinet alongside the mill on the wall rather than on the back of the mill. this will allow me to put the back of the mill against the wall to save space. The footprint of the mill is: X = 73" wide (with table centered, 103" for full X travel), Y = 60" (front to back), and Z = 94" (with head full up). Advertised weight = 6000 pounds.

Centroid Control:
I have acquired: oak board, PLC add 1616 (for ATC control), Centroid Nuc CNC PC with CNC 12 software, DP4 probe, TT1 tool setter, Centroid wireless MPG, options: rigid tapping and unlimited G code file size.

Servos, Servo Drives, and VFD
X, Y, Z servos are Yaskawa Sigma 5, 1 kw AC, with 20 bit encoders (SGMGV-09ADA61), and corresponding Yaskawa Drivers (SGDV-7R6A01A). The spindle motor VFD is a Yaskawa GA700, 200V, 3P, 7.5 kW (CIPR-GA70T2042ABAA-CAAAAA), with a Yaskawa PB-X3 encoder feedback expansion card for operation in closed loop vector mode.

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Last edited by jhenise on Tue Oct 01, 2019 10:08 pm, edited 1 time in total.
jhenise
Posts: 76
Joined: Fri May 24, 2019 8:31 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: kit 103591 CNC12 SN XBBHIDEBGBC

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by jhenise »

My first question!

I am researching pulleys and belts for the X, Y, and X servos, and am thinking of going with Gates GT3 series, 5mm pitch, and 15 or 25mm width...
https://assets.gates.com/content/dam/ga ... 5_2014.pdf

My main question is what gear ratio should I shoot for?

the Yaskawa sigma 5 AC servos (SGMGV-09ADA61)are rated 0.85 kW, and produce 5.4 N.M (47.8 in-lbs) torque (continuous) and up to 13.8 N.M (122.1 in-lbs) torque (peak) @ 3000 RPM peak (1500 RPM "rated")...

If i go with a 1.5:1 reduction with the pulleys that allows 400 IPM rapids at 3000 RPM...

Although I am sure folks here have experience with these servos on bed mills and appropriate gear ratios...
Last edited by jhenise on Tue Oct 15, 2019 8:12 pm, edited 2 times in total.
cncsnw
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Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by cncsnw »

It is not too critical. Anything between 1:1 and 2:1 would probably work fine.

As I am sure you have already figured out, you are trading between rapid rates and precision/thrust.

Your suggested 1.5:1 (or 3:2) does look like a sweet spot. There is little need for rapids exceeding 400 in/min on a machine this size, especially if there is not a full enclosure. 1.5:1 would give you about 1200 lbs linear thrust at the motors' continuous torque rating, which should be plenty.

If you want to get the full 3000 RPM maximum speed, you will need to set the encoder resolution from the drives to the Centroid control at 16384 counts/turn (rather than the 32768 counts/turn suggested as a default in TB267). However, you would still have about 125K encoder counts per inch, which should allow you to hold a tenth or two if the rest of the mechanics and tooling are up to the task.
jhenise
Posts: 76
Joined: Fri May 24, 2019 8:31 pm
Acorn CNC Controller: No
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Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: kit 103591 CNC12 SN XBBHIDEBGBC

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by jhenise »

Thanks for the input.

I have been looking into sizing the Gates GT3 Powergrip belts for the X, Y, Z axis.

Again I am using Yaskawa Sigma 5 1kW AC servos (centroid sells them so i am sure someone here has experience sizing belts for them!)
from the servo manual they can produce:
5.4 NM torque at up 3000 RPM continuous rated this equates to about 2.28 HP
and
13.8 NM torque instantaneous rated, this is 4.85 Hp @ 2500 RPM and 5.81 HP @ 3000 RPM

Do i size the belt for the normal expected operating power or the instantaneous power?

gates recommends multiplying your HP buy a service factor of 1.6 for this application
in the continuous rated torque zone, 1500-3000 RPM, and with service factor the drive would be sized as 1.8-3.6 HP
in the instantaneous rated torque zone, 1500-3000 RPM, and service factor the drive would be sized as 4.7-9.3 HP

A 15mm wide 5mm pitch GT3 belt it rated for 5.3 HP
A 25mm wide 5mm pitch GT3 belt is rated for 9.8 HP

It seems like the 15mm belt would be within spec for most all normal operation, and the 25mm can handle all the power this machine can ever dream of producing in the most severe case...

Finding pulleys for these belts is a little complicated. I haven't found any thing off the shelf with the metric keyed bores that i need (19 and 25mm).

these CMT pulleys are very attractive with the keyless hubs
https://www.cmtco.com/

Does one have experience with Gates GT2 or GT3 belts on mill axis of similar size and power? is 25mm overkill?
Do pulleys need to be steel for long life or is aluminum sufficient?
Last edited by jhenise on Fri Oct 18, 2019 5:37 pm, edited 1 time in total.
tblough
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Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by tblough »

Check out Misumi - https://us.misumi-ec.com/ and look at their 2GT/EV8YU or even better the MR2/MR5 series belts and pulleys. If you keep trash out of the belts, aluminum pulleys work just fine and reduce system inertia.

Keyless with Trantorque bushings is definitely the way to go. Misumi sells the equivalent as well.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
jhenise
Posts: 76
Joined: Fri May 24, 2019 8:31 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: kit 103591 CNC12 SN XBBHIDEBGBC

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by jhenise »

can Trantorque bushings be used on the ball screws?

It looks like the nut on the ball screw must be used to load the pulley/spacer against the bearing that supports the screw to take up play...
It there some way to eliminate using a keyed pulley on the ball screw end?
tblough
Posts: 2329
Joined: Tue Mar 22, 2016 10:03 am
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CNC12: Yes
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CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192
Location: Boston, MA
Contact:

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by tblough »

If you look at the diagram of the Trantorque Mini's, you'll see that the portion that is against the shaft does not move when tightened.
Trantorque Mini.png
Trantorque Mini.png (4.79 KiB) Viewed 3719 times
When you tighten the nut, the outer portion and the timing belt pulley will move to the right in the image above. Mine moved about 0.045" from finger tight to the recommend torque.
I just made spacers with shoulders that made sure they touched only the inner portion of the Trantorque and tightened away. You will need to use a crowsfoot wrench and adjust the torque values accordingly.
X-Axis Drive.JPG
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
jhenise
Posts: 76
Joined: Fri May 24, 2019 8:31 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: kit 103591 CNC12 SN XBBHIDEBGBC

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by jhenise »

perfect! thanks.

I ordered the Fenner Trantorque bushings, Hard anodize aluminum smooth bore pulleys from Misumi (MR5 with the Gates GT profile), and genuine Gates GT3 belts...
jhenise
Posts: 76
Joined: Fri May 24, 2019 8:31 pm
Acorn CNC Controller: No
Allin1DC CNC Controller: No
Oak CNC controller: Yes
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: kit 103591 CNC12 SN XBBHIDEBGBC

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by jhenise »

Does anyone know the model number of the plug on the OAK end of the Centroid to Oak Cable?
I need to make these cables much shorter since I don't have room in my cabinet for all the excess!

Centroid does not offer shorter cables...

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martyscncgarage
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Location: Mesa, AZ

Re: Oak Control, Yaskawa Servos, on Brand New Rigid Head Bed Mill with ATC

Post by martyscncgarage »

jhenise wrote: Tue Oct 29, 2019 5:20 pm Does anyone know the model number of the plug on the OAK end of the Centroid to Oak Cable?
I need to make these cables much shorter since I don't have room in my cabinet for all the excess!

Centroid does not offer shorter cables...

Image
You can't coil up the excess and find a place for? Boy, I'd try hard before reconnectorizing...I hate connectorizing... :x
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
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