Author Topic: Right motors, PSU for CNC mill  (Read 1171 times)

0 Members and 1 Guest are viewing this topic.

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Right motors, PSU for CNC mill
« on: August 08, 2019, 05:57:09 pm »
Hello,

I know this is probably a bit out of topic but I'm making DIY CNC (100x100 modified WorkBee) and don't know what motors should I buy:
Nema23 23HS2430B 3A 112mm 1.7 Kg   OR   Nema23 23HS8430B 3A 76mm 1.2 Kg

Will TB6600 drivers be sufficient for those motors?

I probably will be using standard T8 2mm leadscrew. I want to mill thick aluminum with this CNC.

Thanks in advance.
« Last Edit: September 16, 2019, 03:11:07 pm by 3dgeo »
 

Offline jmelson

  • Super Contributor
  • ***
  • Posts: 1236
  • Country: us
Re: Right motors for CNC mill
« Reply #1 on: August 08, 2019, 07:04:07 pm »
The second motor has half the inductance, which means the same driver at the same DC supply voltage can spin it about twice as fast.
As to which motor provides the desired running torque at the speed you want, that is harder to extrapolate from the given data.  Note that steppers have WAY less running torque that their holding torque rating.  If you can find a graph of running torque for these motors with a specific driver and supply voltage, then you can make intelligent comparisons.

Jon
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #2 on: August 08, 2019, 07:18:42 pm »
As far as I know all similar CNC uses 2nd (smaller) motors, but motors prices are similar enough to consider bigger motors if it will give any additional benefits. I'm thinking that weight might be an issue if I'll go with bigger motors.
To be honest I think both motors have enough torque to do the job.
 

Offline patrick1

  • Contributor
  • Posts: 49
  • Country: au
Re: Right motors for CNC mill
« Reply #3 on: August 09, 2019, 08:57:42 am »
cool project,   so are you using the existing control board ?, and adding breakout board aftermarket drivers too accommodate for the larger motors, - if so, - how too you set a larger bed size for the board ?, or can this just be done in the slicer ?
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #4 on: August 09, 2019, 10:43:17 am »
It's not a 3D printer, it's a CNC mill. I'm also making Prusa MK3 clone, tho this is not it.
For now as a control board I'll use any compatible Arduino I have on hand and connect it directly to stepper drivers, later I want to make my own control/driver board with advanced drivers, like Prusas printer has, but beefier so they can drive Nema23.
Looks like there is no CNC mill board with advanced drivers like that, so this might be a good product to sell as well.
 

Offline larrybl

  • Regular Contributor
  • *
  • Posts: 97
  • Country: us
Re: Right motors for CNC mill
« Reply #5 on: August 09, 2019, 01:23:27 pm »
Search YT for "This old Tony" He built a CNC from scratch and goes over a lot of the details involved.
 
The following users thanked this post: cpt.armadillo

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors for CNC mill
« Reply #6 on: August 09, 2019, 01:51:44 pm »
It's not a 3D printer, it's a CNC mill. I'm also making Prusa MK3 clone, tho this is not it.
For now as a control board I'll use any compatible Arduino I have on hand and connect it directly to stepper drivers, later I want to make my own control/driver board with advanced drivers, like Prusas printer has, but beefier so they can drive Nema23.
Looks like there is no CNC mill board with advanced drivers like that, so this might be a good product to sell as well.

I made this but I doubt many would pay a price for it that makes worth the effort of making and selling
 

Offline David Hess

  • Super Contributor
  • ***
  • Posts: 9902
  • Country: us
  • DavidH
Re: Right motors for CNC mill
« Reply #7 on: August 09, 2019, 03:44:49 pm »
I would use the larger motor.  The supply voltage can always be raised if necessary to improve high speed torque.
 
The following users thanked this post: Siwastaja

Offline patrick1

  • Contributor
  • Posts: 49
  • Country: au
Re: Right motors for CNC mill
« Reply #8 on: August 09, 2019, 04:11:27 pm »


I made this but I doubt many would pay a price for it that makes worth the effort of making and selling
[/quote]

Great Piece of work.    but your right, i would not want too buy one... or rather i would, but its like *i wont make my own drill or vacuum cleaner.... *      ... so little of the learning is widely applicable too what i do...  i would get more out of giving you my heart felt congratulations,     and continue with perpetual motion builds ;-D
 

Offline SparkyFX

  • Frequent Contributor
  • **
  • Posts: 507
  • Country: de
Re: Right motors for CNC mill
« Reply #9 on: August 09, 2019, 04:48:24 pm »
I probably will be using standard T8 2mm leadscrew. I want to mill thick aluminum with this CNC.
What shouldn´t be underestimated is that Aluminium (in general, there are several variants with vastly different properties) is "best" cut with a single flute cutter (given there is no flood cooling that washes chips out of the cutter and on a small machine), which results in higher cutting force per revolution should you aim for normal/higher feedrates. Depending on the cutter you also might need to cut deeper to actually get a working result, the rake angle for alu is steeper than e.g. steel, so experience from working with steel on bigger machines might not be comparable.

Which means for the positioning motors: as big as you can get and highest torque at lower speed. You need the high speed only for the rapid moves, where no cutting forces will slow the machine down. For deep cuts in alu you need a rigid machine or at least a closed loop control, losing steps ruins the experience and work otherwise (meaning you need to slow the feedrates significantly, where you need the torque)
Support your local planet.
 
The following users thanked this post: dom0

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #10 on: August 12, 2019, 11:49:10 am »
I made this but I doubt many would pay a price for it that makes worth the effort of making and selling

Pff, if you don't sell you will never know, put few on tindie and you will see.
I want to make commercial grade board with all the bells and whistles, but only time will tell if I do...

What drivers did You use?
Is that a "mega2560" chip? If so I don't understand why people still use that chip cos there are many way cheaper and way more powerful alternatives.

I would use the larger motor.  The supply voltage can always be raised if necessary to improve high speed torque.

OK, thanks, +1point goes for larger motors

What shouldn´t be underestimated is that Aluminium (in general, there are several variants with vastly different properties) is "best" cut with a single flute cutter (given there is no flood cooling that washes chips out of the cutter and on a small machine), which results in higher cutting force per revolution should you aim for normal/higher feedrates. Depending on the cutter you also might need to cut deeper to actually get a working result, the rake angle for alu is steeper than e.g. steel, so experience from working with steel on bigger machines might not be comparable.

Which means for the positioning motors: as big as you can get and highest torque at lower speed. You need the high speed only for the rapid moves, where no cutting forces will slow the machine down. For deep cuts in alu you need a rigid machine or at least a closed loop control, losing steps ruins the experience and work otherwise (meaning you need to slow the feedrates significantly, where you need the torque)

Well, I can get even bigger motors, but I thin that would be overkill for machine like this. Every workbee I've seen uses smaller motors.

+1point goes for larger motors

Well, I guess in the end bigger motors won :)
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors for CNC mill
« Reply #11 on: August 12, 2019, 12:12:56 pm »
I made this but I doubt many would pay a price for it that makes worth the effort of making and selling

Pff, if you don't sell you will never know, put few on tindie and you will see.
I want to make commercial grade board with all the bells and whistles, but only time will tell if I do...

What drivers did You use?
Is that a "mega2560" chip? If so I don't understand why people still use that chip cos there are many way cheaper and way more powerful alternatives.

stm32f407 and powerstep01 drivers

 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #12 on: August 12, 2019, 01:14:38 pm »
stm32f407 and powerstep01 drivers

Wow, those are really nice drivers.
At what current You are using them and do they become hot after a while with that current?
 

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 9067
  • Country: my
  • reassessing directives...
Re: Right motors for CNC mill
« Reply #13 on: August 12, 2019, 02:59:03 pm »
fwiw... 6040 frame is coming my way... the first bit of pieces i bought for this project was the 500W spindle with psu and few collets acc 2 years ago, and then few NEMA23 and TB6600 drivers. i wont know how they fair up or if they even working, because i never try, they just stayed in the storage all this years. others acc such towline, cables etc also ready, its only which control board that i'm going to use. did a research on the control SW, Mach3 needs payment to get full version license, so does the TeeksCNC? or what the name was, i think can find the free OSS version if i search harder. not really a big deal, i think can mod RepRAP workflow to work with a CNC. i thought i can build my own sturdy table for this, but thinking i dont have necessary tools and accuracy to build one, and i have to buy backlash free threads, bearings, heavy metals for table top or specialized grade A aluminium frame etc thats going to cost me money anyway, so after 2 years of dreaming i just bought the 6040 frame from aliexpress, now i think i've spent 80-90% of the cost, it should be near before i can complete my CNC project.. maybe in the next 1-2 years? ;D my incomplete gigantic 3d printer is there standing outside collecting collosal amount of dust for many more years waiting to be resumed :palm: with this post, this thread is now subscribed... ymmv.
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors for CNC mill
« Reply #14 on: August 12, 2019, 04:47:19 pm »
stm32f407 and powerstep01 drivers

Wow, those are really nice drivers.
At what current You are using them and do they become hot after a while with that current?

as far as I remember 4-5A, they get no hotter than you can keep a finger on them so maybe 60'C
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #15 on: August 12, 2019, 05:37:24 pm »
... with this post, this thread is now subscribed... ymmv.

 :-DD That's the way to subscribe to thread...  :-DD
I really hope I'll build it faster, I have mine designed with 3D, so all I need to do is buy/cut parts and add them together...
I contacted bigger motor seller and asked if he can sell outside of Ebay, Ebay collects way more money then original price is stating and there is no one to ask why – I've had enough with that cap, I'm not buying directly from Ebay anymore...
C and other beams I'll buy from Greece, they sell them cheaper than China and ships them way cheaper and faster.
I'm considering These Ball screws instead of regular lead screws, but I doubt I can fit them without changing the design.
Also I haven't decided on software yet, and for a mill I think 500W will be a bit weak, I'll probably go with 1.5KW.

as far as I remember 4-5A, they get no hotter than you can keep a finger on them so maybe 60'C
I'll probably go with them as well, they look really good on paper.
Mind sharing Your board design?  ::)
« Last Edit: August 12, 2019, 05:41:56 pm by 3dgeo »
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors for CNC mill
« Reply #16 on: August 12, 2019, 08:17:31 pm »
... with this post, this thread is now subscribed... ymmv.

 :-DD That's the way to subscribe to thread...  :-DD
I really hope I'll build it faster, I have mine designed with 3D, so all I need to do is buy/cut parts and add them together...
I contacted bigger motor seller and asked if he can sell outside of Ebay, Ebay collects way more money then original price is stating and there is no one to ask why – I've had enough with that cap, I'm not buying directly from Ebay anymore...
C and other beams I'll buy from Greece, they sell them cheaper than China and ships them way cheaper and faster.
I'm considering These Ball screws instead of regular lead screws, but I doubt I can fit them without changing the design.
Also I haven't decided on software yet, and for a mill I think 500W will be a bit weak, I'll probably go with 1.5KW.

as far as I remember 4-5A, they get no hotter than you can keep a finger on them so maybe 60'C
I'll probably go with them as well, they look really good on paper.
Mind sharing Your board design?  ::)

not really, but you are looking at +$100 worth of parts, a 4 layer board, you will also need a stencil
and because of some quirks in how the drivers are controlled it only works with my port of GRBL

So I don't think it would be very useful
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #17 on: August 12, 2019, 11:22:59 pm »
not really, but you are looking at +$100 worth of parts, a 4 layer board, you will also need a stencil
and because of some quirks in how the drivers are controlled it only works with my port of GRBL

So I don't think it would be very useful

Over 100?  ??? What is so expensive?  :o Driver chips – 9 buks a pop, 4layer PCB like 10-15buks a pop, MCU 5/pop, so far  60. Passives and connectors are not that expensive, or I'm missing something? You don't need stencil, can hotair it without it easily.

Tell me more why you picked that MCU, 82 IO 512K mem, 192K ram, 168Mhz seems a bit overkill if you ask me... Why simple STM32F103 is not enough? P.S. dam, LCSC cranked price on those, sad times.....

BTW, how hard would be to integrate ESP32 as an MCU? I'm talking about software side, hardware wise shouldn't be hard at all. That BT or WIFI in CNC would be very cool....
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors for CNC mill
« Reply #18 on: August 13, 2019, 12:29:32 pm »
not really, but you are looking at +$100 worth of parts, a 4 layer board, you will also need a stencil
and because of some quirks in how the drivers are controlled it only works with my port of GRBL

So I don't think it would be very useful

Over 100?  ??? What is so expensive?  :o Driver chips – 9 buks a pop, 4layer PCB like 10-15buks a pop, MCU 5/pop, so far  60. Passives and connectors are not that expensive, or I'm missing something? You don't need stencil, can hotair it without it easily.

Tell me more why you picked that MCU, 82 IO 512K mem, 192K ram, 168Mhz seems a bit overkill if you ask me... Why simple STM32F103 is not enough? P.S. dam, LCSC cranked price on those, sad times.....

BTW, how hard would be to integrate ESP32 as an MCU? I'm talking about software side, hardware wise shouldn't be hard at all. That BT or WIFI in CNC would be very cool....

if you are not buying china specials and only building one connectors/passives and enclosure adds up, even from jlpcb etc. PCBs is double that since you can't get less than 5 and if you don't want to wait add the same for shipping

sure you can hot air almost anything, but the powerstep is not a your average package and if you screw it up the board is junk

I used the mcu because I use it in other projects and on a one-of it would be pointless trying so save a few dollars on the mcu

there's a connector for an esp-01, considering all the other things that can go wrong on a CNC I wouldn't want  to share cpu with a wifi stack, I'm not even sure I'd want wifi

 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors for CNC mill
« Reply #19 on: August 13, 2019, 02:02:36 pm »
if you are not buying china specials and only building one connectors/passives and enclosure adds up, even from jlpcb etc. PCBs is double that since you can't get less than 5 and if you don't want to wait add the same for shipping
Maybe, not gonna argue with that. But if You would make them in bulk price is way less than 100, one offs is always very expensive.

sure you can hot air almost anything, but the powerstep is not a your average package and if you screw it up the board is junk
Can't imagine how bad you should screw it up to make board useless :) Just watch Lous Rossmann, that dude do crazy stuff with boards and don't screw them up, the secret is to use enough flux  :-DD

I used the mcu because I use it in other projects and on a one-of it would be pointless trying so save a few dollars on the mcu

there's a connector for an esp-01, considering all the other things that can go wrong on a CNC I wouldn't want  to share cpu with a wifi stack, I'm not even sure I'd want wifi
EPS32 has two cores, on for WIFI stuff other for user code, so it should be a variable option.
Anyway, it's a bit too early to talk about control board, first I have to make frame itself :) Tho I'm very thankful for letting me know about those awesome drivers. I was gonna use 3A ones, was't happy about their amperage, but they also had SPI, stall detection and other fancy features.
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #20 on: September 16, 2019, 03:56:49 pm »
I'm back again to nag more  :-DD this time abut PSU.

According to this stepper PSU guide I made some calculations and got these numbers:
Bigger motors 83V, smaller 60V @8A

I can make my own PSU from thransformer, but looks like making it will be more expensive than just to buy something like this puppy: HRPG-1000-48 (21A).
I know this is a way overkill, but it's still cheaper than to build my own PSU from transformers (prove me wrong).
I can overvoltage this PSU to 56V and drive smaller motors very close to their limits or bigger motors still far from heirs, tho should I worry about back EMF with this PSU?

Using this voltage it looks like cheap drivers will not cut it – TB6600 only up to 45V...  :-\

Do numbers above look OK or I missed something? What is recommended "distance" from max voltage (I'll probably go with bigger motors)?

Share your PSU and motors specs please.
« Last Edit: September 16, 2019, 03:58:35 pm by 3dgeo »
 

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 9067
  • Country: my
  • reassessing directives...
Re: Right motors, PSU for CNC mill
« Reply #21 on: September 16, 2019, 08:44:14 pm »
or I missed something?
you probably missed that most people in google build CNC with TB6600 and NEMA23.. unless you want to cut high speed steel, then you'll need a lot larger stepper and driver and PSU, good luck building frame for it. ymmv.

Share your PSU and motors specs please.
i also missed that most people use 24V PSU to power NEMA23 through the TB6600 (40V max), i have few 12V PSU unit bought earlier for the giant 3d printer project, but forgot that i have no 24V PSU in stock, so i'm ordering just few days ago from aliexpress, the 41A version, $40+ cheap i hope i'll get better than what i paid for :P am also ordering this, just in case it will do any good?



i always been meaning to have a proper lathe, maybe this should do the trick? i'm aiming for maximum 5 axis utilization, now i have more nema23 and tb6600 than needed (spare parts) just need to figure out later what fw-sw controller-cam toolchain that i'm going to use, diy gcode scripter comes to mind, dreaming and dreaming. i'm planning to utilize old marlin fw that was designed for 3d printer, so i have to make a converter or emulator board to turn spindle RPM close loop control into a plastic squirter's nozzle's heater's temperature feedback, highly experimental, highly unprovable, not yet. pcb already sent to seeedstudio yesterday, after days of laying out traces until the eyes blurred due to lack of sleep, no word from swmbo she got used to it i guess. thought i have to put this project upfront since many other projects will require this. without this i have to do the hardwork again of handsaw cut and backpain, with this machine working, the rest should be alot easier, i hope.

some of the parts gathered so far, after 2 years or more of dreaming.... maybe the better place for discussion and collecting intel is cnczone or reprap cnc...
« Last Edit: September 16, 2019, 08:48:56 pm by Mechatrommer »
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 
The following users thanked this post: 3dgeo

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #22 on: September 17, 2019, 01:36:44 am »
I'm aware that most people uses TB6600 and NEMA23, that was my plan as well. Tho I want to do it "properly", but as usual – my knowledge on the matter is not sufficient.
Those calculations looked kinda strange – bigger motors rated for 1.6 Ohms/phase, so 3A * 1.6 Ohms is 4.8V, so whats the point to use high voltage PSUs? 12V with 3A current limit should be fine...? :-//
I don't want to cut steel, tho it should be able to cut aluminum.

i'm ordering just few days ago from aliexpress, the 41A version, $40+ cheap i hope i'll get better than what i paid for :P am also ordering this, just in case it will do any good?

What comes to PSU purchase – this is the only part I'm not brave enough to buy from Aliexpess, I rather go with well known brand purchased  from well known distributor. I'm not trusting my shop or home to a cheap PSU knockoff from Ali even if I'll have to pay 10 times more.
I've seen "AVE" used similar "lathe" – if it's good for him it should be good for everyone  ;D Actually this is 4 axis (not a lathe) – it's purpose to make precise "slow" movements (that's why stepper is used). Lathe purpose is to spin fast, relatively speaking rotation precision doesn't matter for lathe.
Sadly, I have no knowledge on 4 or 5 axis milling, solid 3 axis mashine will be plenty for me for a while  ::)

some of the parts gathered so far, after 2 years or more of dreaming.... maybe the better place for discussion and collecting intel is cnczone or reprap cnc...

Looks solid machine, tho that mill looks way underpowered?  :horse:
And no, I think this is a better place, cos I have questions on electrical part, not so much on a mechanical.
« Last Edit: September 17, 2019, 01:42:00 am by 3dgeo »
 

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 9067
  • Country: my
  • reassessing directives...
Re: Right motors, PSU for CNC mill
« Reply #23 on: September 17, 2019, 05:07:37 am »
I'm aware that most people uses TB6600 and NEMA23, that was my plan as well. Tho I want to do it "properly", but as usual – my knowledge on the matter is not sufficient.
Those calculations looked kinda strange – bigger motors rated for 1.6 Ohms/phase, so 3A * 1.6 Ohms is 4.8V, so whats the point to use high voltage PSUs? 12V with 3A current limit should be fine...? :-//
i think your calculation is for stall condition, and ignoring the wiring resistance, mosfet Vds loss in the driver circuit, and other losses here and there in the whole system. i wont bet 5V PSU will give me enough juice to deal with the losses. you may try 12V but since everybody in the net is going the 24V route, so getting it at $40 part will not hurt much, it can be a good investment for later project if it turned out not suitable for this job. i already have few 12V PSU to play with, and its also easily available in form of PC ATX PSU sold everywhere locally. mosfets in the stepper driver maybe happy with higher voltage, who knows? about trusting the china design, well maybe there's few caps and mosfets need replacement in case of smoke comes out, but i'm not going to trust brand name either. i had Gigabyte brand ATX PSU that failed much earlier than no name brand PSU, i have HP (USA?) Z800 server PC workstation coming this way with PSU issues discussed everywhere in the net, so even USA brand is not a bulletproof product. but everybody is free to choose what they like.

Actually this is 4 axis (not a lathe) – it's purpose to make precise "slow" movements (that's why stepper is used). Lathe purpose is to spin fast, relatively speaking rotation precision doesn't matter for lathe.
yes thats why i'm planning to mod it to be connected to a dc or bldc motor later to become a lathe, and also thats why i have to go to the hassle to build a converter circuit to read its rpm to thermistor voltage (close loop rpm control) to make it reprap/marlin compatible, a stepper motor wont need such converter. at first i was eyeing on the "5th axis cnc" in aliexpress, the cheapest version is like this... its wonderful how cheap it is nowadays, if its from USA, its going to be 10X cost more, but with higher quality of course, but whats good it is to hobbiest if its not affordable? but further meditation made me come with a conclusion that it will be more difficult to mod "4th and 5th axis jig" like that to become 4th axis turn machine or lathe. so the vote went to the 4th axis turn machine, should be easier to mod to lathe or add a 5th axis later (after i build some metal rig with 3 or 4 axis CNC).

Sadly, I have no knowledge on 4 or 5 axis milling, solid 3 axis mashine will be plenty for me for a while  ::)
yes its understandable. in fact most people will do great with 3 axis, but i want to do all possibility that i think i will be going to get later while i am at this matter right now.

Looks solid machine, tho that mill looks way underpowered?  :horse:
yes probably so, thats why this is going to be try and error myself, iirc 1.5KW spindle was too expensive for me 2 years ago. at least it should be good cutting or drilling some wood or plastics. the 6040Z frame came with 65mm dia spindle holder, that should be able to hold larger spindle motor, but for now, it is for spare part as i've mounted the 52mm spindle holder that came with the 500W motor earlier.

cheers and best regards,
The Mechatrommer.
« Last Edit: September 17, 2019, 05:09:48 am by Mechatrommer »
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors, PSU for CNC mill
« Reply #24 on: September 17, 2019, 09:07:43 am »
I'm aware that most people uses TB6600 and NEMA23, that was my plan as well. Tho I want to do it "properly", but as usual – my knowledge on the matter is not sufficient.
Those calculations looked kinda strange – bigger motors rated for 1.6 Ohms/phase, so 3A * 1.6 Ohms is 4.8V, so whats the point to use high voltage PSUs? 12V with 3A current limit should be fine...? :-//
i think your calculation is for stall condition, and ignoring the wiring resistance, mosfet Vds loss in the driver circuit, and other losses here and there in the whole system. i wont bet 5V PSU will give me enough juice to deal with the losses. you may try 12V but since everybody in the net is going the 24V route, so getting it at $40 part will not hurt much, it can be a good investment for later project if it turned out not suitable for this job. i already have few 12V PSU to play with, and its also easily available in form of PC ATX PSU sold everywhere locally. mosfets in the stepper driver maybe happy with higher voltage, who knows?

that's fundamental to how stepper drivers work. Steppers are big inductors so the higher the driver voltage the faster you can reach max current, iow the higher the voltage
the faster you can step without losing all your torque. I'd say 24V is a bare minimum

https://www.electrocraft.com/img/products/stepper/torque_TPP23-90A10.png


 
The following users thanked this post: Mechatrommer

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #25 on: September 20, 2019, 11:22:45 pm »
i already have few 12V PSU to play with, and its also easily available in form of PC ATX PSU sold everywhere locally. mosfets in the stepper driver maybe happy with higher voltage, who knows?
I have many PC PSUs as well, they should be OK for testing. I agree that for a big CNC 12V is not enough, tho my choice would be to go with 48V or more, I actually found cheap enough toroidal transformer, so making my own PSU is not out of the question yet.

about trusting the china design, well maybe there's few caps and mosfets need replacement in case of smoke comes out, but i'm not going to trust brand name either. i had Gigabyte brand ATX PSU that failed much earlier than no name brand PSU, i have HP (USA?) Z800 server PC workstation coming this way with PSU issues discussed everywhere in the net, so even USA brand is not a bulletproof product. but everybody is free to choose what they like.
I have no PSU design experience, bus as far as I understand brand like MeanWell ads more protection features as well. Talking about good known brands making mistakes – I had 500Eur worth brand new Asus server/workstation motherboard literally exploding to my face – one cap blew up and flied straight to my neck and burned my neck a little (no permanent damage). And it wasn't my mistake, something went wrong with CPU power delivery. It killed one of two 8 core CPUs in the process. Tho Asus support was good, they dispatched new motherboard right away, delivery person whom delivered new board took old board and dead CPU. Asus compensated for dead CPU as well. I have to mention one bad thing – that "new" board was refurbished and signs of wear was visible, so I asked them to fix my broken board that was actually new, not refurbished. And they did, they send back my fixed board and took replacement back.
The moral is – no one is perfect, tho extra cost for well known brand includes better support, arguably better components, features and they need to keep their name "clean" even in bad situations :)

Z800? Ancient 1366 double socket? I have Intel S5520SC motherboard and couple of X5647 collecting dust  ;D

yes thats why i'm planning to mod it to be connected to a dc or bldc motor later to become a lathe, and also thats why i have to go to the hassle to build a converter circuit to read its rpm to thermistor voltage (close loop rpm control) to make it reprap/marlin compatible, a stepper motor wont need such converter.
I can't understand why you want to put a lathe on your CNC mill ??? I'm not an expert on the matter but if you make your own ESC you can track motor spin speed via MCU or hack prebuilt driver MCU to get RPM, check Electronoob videos



that's fundamental to how stepper drivers work. Steppers are big inductors so the higher the driver voltage the faster you can reach max current, iow the higher the voltage the faster you can step without losing all your torque. I'd say 24V is a bare minimum

Any useful links for dummies on this topic?  ;D

P.S. langwadt – I really want to build stepper driver board with powerstep01 as well, do you have any notes, warnings on PCB design? Any interference, instability issues that I should know about? How far from recommended design yours PCB is? I'm not sure at this point, but I want to try to make it modular – every driver on its own PCB and use aviation plugs and solder their wires as close to powerstep01 as possible, but still leave plenty space for additional aluminum heat sink if needed. What you think about this? I bet those drivers work way more silent and smoother than cheap drivers...
« Last Edit: September 20, 2019, 11:41:13 pm by 3dgeo »
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors, PSU for CNC mill
« Reply #26 on: September 21, 2019, 10:34:02 am »

that's fundamental to how stepper drivers work. Steppers are big inductors so the higher the driver voltage the faster you can reach max current, iow the higher the voltage the faster you can step without losing all your torque. I'd say 24V is a bare minimum

Any useful links for dummies on this topic?  ;D

P.S. langwadt – I really want to build stepper driver board with powerstep01 as well, do you have any notes, warnings on PCB design? Any interference, instability issues that I should know about? How far from recommended design yours PCB is? I'm not sure at this point, but I want to try to make it modular – every driver on its own PCB and use aviation plugs and solder their wires as close to powerstep01 as possible, but still leave plenty space for additional aluminum heat sink if needed. What you think about this? I bet those drivers work way more silent and smoother than cheap drivers...

nothing special about the pcb, main objective was that I wanted four drivers with connectors fit in a 100mm wide box.
if you want modular just buy some X-NUCLEO-IHM03A1

they aren't particularly smooth or silent, if you want that tmc5160/tmc2160 with external fets is a better choice and they have standard step/direction drive so will work with standard motion controllers

 

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 9067
  • Country: my
  • reassessing directives...
Re: Right motors, PSU for CNC mill
« Reply #27 on: September 21, 2019, 12:05:23 pm »
I can't understand why you want to put a lathe on your CNC mill ??? I'm not an expert on the matter but if you make your own ESC you can track motor spin speed via MCU or hack prebuilt driver MCU to get RPM
because i want a unified solution for my CNC, it can be switched between lathe and 4th axis CNC by switching the motor. usually lathe cutter is manually controlled, this time i want the CNC head (X and Z axis movement) as automated cutter. maybe i can save up later to get $1000+ dedicated mini lathe machine, but i want to see possibility with this project, if its possible then i dont have to buy dedicated lathe machine. if not, then its another waste of money that i will try to repurpose the parts as much as i can. this is try and error i'm no expert i can be wrong. btw, the 4th axis arrived and tested yesterday, real bulky, even the tailstock that came with it (125mm+ length). i have to arrange properly or find a better way of locking it on to fit on my limited 6040 platform. ymmv.

about the RPM detector. i want to make an emulator board for 3d printer marlin FW that i'm planning to use, maybe if its done then it will become clearer to you. it will emulate voltage output produced by 3d printer thermistor with 4.7Kohm pull up to 5V. PWM from marlin/arduino board that is used to control heat element will be used to emulate motor control by slowly ramping up or down, similar to heat element respond. and later i will try to increase freq of control loop respond etc. anyway this is try and error again no hard prove its going to work, only bragging about my plan. thanks for the ESC RPM hack link, but i believe i will need extra effort and pcb too if i'm going that route, to emulate ESC to make compatible with marlin, but BLDC motor is a nice option. i have few china ESC around for my future drone project, so i can grab one of them if i want to. cheers and sorry my english.
« Last Edit: September 21, 2019, 12:07:49 pm by Mechatrommer »
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline SparkyFX

  • Frequent Contributor
  • **
  • Posts: 507
  • Country: de
Re: Right motors, PSU for CNC mill
« Reply #28 on: September 21, 2019, 02:20:47 pm »
4th axis or turning will sooner or later require the spindle to be indexable without changing setup, mostly for live tooling (think hole patterns or keyslots), maybe for feeding stock. An encoder might be the better choice.
Support your local planet.
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #29 on: September 21, 2019, 05:58:01 pm »
nothing special about the pcb, main objective was that I wanted four drivers with connectors fit in a 100mm wide box.
if you want modular just buy some X-NUCLEO-IHM03A1
Did you use regular copper thickness or double? Do you have an idea what max current they can drive with your PCB design with acceptable temperature?
After making it how do you feel – is it worth the time? I know there is X-NUCLEO-IHM03A1, but according to ST they are only for testing only...
You mind sharing machine you using it on?

they aren't particularly smooth or silent, if you want that tmc5160/tmc2160 with external fets is a better choice and they have standard step/direction drive so will work with standard motion controllers
Why they are not smooth or silent? They have 128 microstepping, even tho it isn't 256, but still, they should be silent enough, what gives?
tmc5160/tmc2160 adds an extra step – figuring out right mosfets, and I'm fine with SPI, I actually prefer SPI instead of step/direction.


because i want a unified solution for my CNC, it can be switched between lathe and 4th axis CNC by switching the motor. usually lathe cutter is manually controlled, this time i want the CNC head (X and Z axis movement) as automated cutter. maybe i can save up later to get $1000+ dedicated mini lathe machine, but i want to see possibility with this project, if its possible then i dont have to buy dedicated lathe machine. if not, then its another waste of money that i will try to repurpose the parts as much as i can. this is try and error i'm no expert i can be wrong. btw, the 4th axis arrived and tested yesterday, real bulky, even the tailstock that came with it (125mm+ length). i have to arrange properly or find a better way of locking it on to fit on my limited 6040 platform. ymmv.
1000 for lathe? Is it made from gold? :D Lathe sized like your 4 axis should cost like 200 buks... I still can't understand why you need lathe on CNC machine, just use your 4 axis and stepper motor to rotate it slowly – let milling bit do the job. If you really want CNC lathe just buy dedicated lathe and add XY axis to it to make it CNC...
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors, PSU for CNC mill
« Reply #30 on: September 21, 2019, 06:29:53 pm »
nothing special about the pcb, main objective was that I wanted four drivers with connectors fit in a 100mm wide box.
if you want modular just buy some X-NUCLEO-IHM03A1
Did you use regular copper thickness or double? Do you have an idea what max current they can drive with your PCB design with acceptable temperature?
After making it how do you feel – is it worth the time? I know there is X-NUCLEO-IHM03A1, but according to ST they are only for testing only...
You mind sharing machine you using it on?

they aren't particularly smooth or silent, if you want that tmc5160/tmc2160 with external fets is a better choice and they have standard step/direction drive so will work with standard motion controllers
Why they are not smooth or silent? They have 128 microstepping, even tho it isn't 256, but still, they should be silent enough, what gives?
tmc5160/tmc2160 adds an extra step – figuring out right mosfets, and I'm fine with SPI, I actually prefer SPI instead of step/direction.

just standard copper. I  don't know what current they can handle but they are fine for my ~4A need, above that the small current sense resistors I used are probably at the limit.

as with most diy electronics, if you have to ask if it is worth the time you shouldn't be doing it

ST says it is for testing only because they haven't bother with all the approval testing and they sell them at give away prices

The machine is cobbled together from aluminium extrusions, mgn12 rails, 1204 ball screws and an 800W spindle

they are smooth and when milling you can't hear them, but at stand still they hiss

there is no advantage in needing spi for direction and it means it won't work with any standard motion controller code

 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #31 on: September 21, 2019, 10:06:29 pm »
just standard copper. I  don't know what current they can handle but they are fine for my ~4A need, above that the small current sense resistors I used are probably at the limit.
Yeah, I don't think my motor will use more than 4A, so I can do 10x10cm as well, tho I might make it from thicker copper. I looked at external mosfets – suitable ones cost a LOT, 36 fets in total – not worth it in this case, so I will stick with all in one chip.

as with most diy electronics, if you have to ask if it is worth the time you shouldn't be doing it
I rephrase it – does it works as you expected? Any regrets, design mistakes?  ;D

The machine is cobbled together from aluminium extrusions, mgn12 rails, 1204 ball screws and an 800W spindle
they are smooth and when milling you can't hear them, but at stand still they hiss

I'm considering mgn12 and ball screws, but I'm not sure they worth that extra cost compared to regular 8mm lead screw and C beams with plastic wheels. I've seen videos that mgn12 on aliexpress are junk, that's why I'm hesitating, how do they work for you and where did you buy them?

there is no advantage in needing spi for direction and it means it won't work with any standard motion controller code
Well, I didn't dig in to powerSTEP01 SPI features, but I'm guessing that stalling detection and other features are communicated via SPI and interrupt pin. Plus I need to learn Gcode anyway, so writing my own controller code to work with SPI is not an issue. Also I just like fancyness of SPI  ^-^
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors, PSU for CNC mill
« Reply #32 on: September 21, 2019, 11:16:51 pm »
just standard copper. I  don't know what current they can handle but they are fine for my ~4A need, above that the small current sense resistors I used are probably at the limit.
Yeah, I don't think my motor will use more than 4A, so I can do 10x10cm as well, tho I might make it from thicker copper. I looked at external mosfets – suitable ones cost a LOT, 36 fets in total – not worth it in this case, so I will stick with all in one chip.

as with most diy electronics, if you have to ask if it is worth the time you shouldn't be doing it
I rephrase it – does it works as you expected? Any regrets, design mistakes?  ;D

The machine is cobbled together from aluminium extrusions, mgn12 rails, 1204 ball screws and an 800W spindle
they are smooth and when milling you can't hear them, but at stand still they hiss

I'm considering mgn12 and ball screws, but I'm not sure they worth that extra cost compared to regular 8mm lead screw and C beams with plastic wheels. I've seen videos that mgn12 on aliexpress are junk, that's why I'm hesitating, how do they work for you and where did you buy them?

there is no advantage in needing spi for direction and it means it won't work with any standard motion controller code
Well, I didn't dig in to powerSTEP01 SPI features, but I'm guessing that stalling detection and other features are communicated via SPI and interrupt pin. Plus I need to learn Gcode anyway, so writing my own controller code to work with SPI is not an issue. Also I just like fancyness of SPI  ^-^

you can get suitable FETs $0.20, the dual dual fet used on the TMC5160-stepStick is ~$0.50

it works as expected, only mistake was two swapped pins on a uart connector. I would have like more of the unused pins on the CPU to be accessible and I should have kept the option to run the motors at higher voltage

even bad mgn12/ballscrews are miles better than plastic wheels on c-beam and lead screws, I bought them from robotdigg
 
I also bought some reasonable nice hgh15 rails on ebay, 2*1500mm + 4 carriages for ~100gbp

SPI is nice for setting currents and reading errors, but for direction it is a hassle, and it has nothing to do with gcode, it is the
firmware that needs modifications

I never got the stall detection to work on the powerstep01, the datasheet it limited on how should be done (to say the least) and
I'm not even sure it works when not using the internal motiongenerator
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #33 on: September 22, 2019, 03:20:32 am »
you can get suitable FETs $0.20, the dual dual fet used on the TMC5160-stepStick is ~$0.50
I think it defeats the purpose of using external fets if fets are that puny. If go with external fets than go all out and use something like IPT015N10N5 tho I bet TMC5160 would choke trying to drive 4 of those beasts with 16000pF capasitance each  >:D Even if it can drive those puppies – total mosfet cost would be 130 usd. Ok, I know those are overkill, but I don't see any point of using small external fets with high resistance.
I guess all come to programming...

it works as expected, only mistake was two swapped pins on a uart connector. I would have like more of the unused pins on the CPU to be accessible and I should have kept the option to run the motors at higher voltage
Swapping uart pins – so common mistake... :D Why didn't you break all pins out? I always do, even if I'm not using them... Whats is limiting the voltage? This is one of the features I like about powerSTEP01 drivers, their max voltage is 85V. I want to have option to drive control board from 60 to 80V.

even bad mgn12/ballscrews are miles better than plastic wheels on c-beam and lead screws, I bought them from robotdigg
Are you sure about this? Cos I think it is way easier to make round plastic wheels and aluminum profiles with high precision than to make rails and keep them straight while shipping. And even if their precision are the same, price difference is huge. I really should go to dedicated CNC forum to find this out to be honest...



I also bought some reasonable nice hgh15 rails on ebay, 2*1500mm + 4 carriages for ~100gbp
This video is why I'm so skeptic about rails:



SPI is nice for setting currents and reading errors, but for direction it is a hassle, and it has nothing to do with gcode, it is the
firmware that needs modifications

I never got the stall detection to work on the powerstep01, the datasheet it limited on how should be done (to say the least) and
I'm not even sure it works when not using the internal motiongenerator

Are you saying that powerSTEP01 has issues what comes to programming?  If so than it's a deal breaker, bin there (and partially still am) with other chip whom documentation sucks and even manufacturer support can't help with the matter...

Do TMC5160 have issues/are pain to program as well?
« Last Edit: September 22, 2019, 03:26:28 am by 3dgeo »
 

Offline langwadt

  • Super Contributor
  • ***
  • Posts: 1433
  • Country: dk
Re: Right motors, PSU for CNC mill
« Reply #34 on: September 22, 2019, 03:54:05 am »
you can get suitable FETs $0.20, the dual dual fet used on the TMC5160-stepStick is ~$0.50
I think it defeats the purpose of using external fets if fets are that puny. If go with external fets than go all out and use something like IPT015N10N5 tho I bet TMC5160 would choke trying to drive 4 of those beasts with 16000pF capasitance each  >:D Even if it can drive those puppies – total mosfet cost would be 130 usd. Ok, I know those are overkill, but I don't see any point of using small external fets with high resistance.
I guess all come to programming...

the fets on the stepstick are 12A and ~6mOhm apart from the 40V rating much more than that would be pointless

it works as expected, only mistake was two swapped pins on a uart connector. I would have like more of the unused pins on the CPU to be accessible and I should have kept the option to run the motors at higher voltage
Swapping uart pins – so common mistake... :D Why didn't you break all pins out? I always do, even if I'm not using them... Whats is limiting the voltage? This is one of the features I like about powerSTEP01 drivers, their max voltage is 85V. I want to have option to drive control board from 60 to 80V.

breaking out the pins take space and even more if they have to go to a reasonable connector
the powersupplies are limited to ~30V input, I had intended to split the input in two, so the motor voltage was separate

even bad mgn12/ballscrews are miles better than plastic wheels on c-beam and lead screws, I bought them from robotdigg
Are you sure about this? Cos I think it is way easier to make round plastic wheels and aluminum profiles with high precision than to make rails and keep them straight while shipping. And even if their precision are the same, price difference is huge. I really should go to dedicated CNC forum to find this out to be honest...

the choice between rails and aluminium with wheels is the choice between cheap and good


I also bought some reasonable nice hgh15 rails on ebay, 2*1500mm + 4 carriages for ~100gbp
This video is why I'm so skeptic about rails:


and if you look at his later videos he is using mgn12 an ballscrews in his latest design


SPI is nice for setting currents and reading errors, but for direction it is a hassle, and it has nothing to do with gcode, it is the
firmware that needs modifications

I never got the stall detection to work on the powerstep01, the datasheet it limited on how should be done (to say the least) and
I'm not even sure it works when not using the internal motiongenerator

Are you saying that powerSTEP01 has issues what comes to programming?  If so than it's a deal breaker, bin there (and partially still am) with other chip whom documentation sucks and even manufacturer support can't help with the matter...

Do TMC5160 have issues/are pain to program as well?


everything complicated is going to be a pain to program, but it the little I've looked at it it seems the documentation on the TMC is better


 

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 9067
  • Country: my
  • reassessing directives...
Re: Right motors, PSU for CNC mill
« Reply #35 on: September 22, 2019, 04:22:20 am »
1000 for lathe? Is it made from gold? :D Lathe sized like your 4 axis should cost like 200 buks... I still can't understand why you need lathe on CNC machine, just use your 4 axis and stepper motor to rotate it slowly – let milling bit do the job. If you really want CNC lathe just buy dedicated lathe and add XY axis to it to make it CNC...
the minimum "proper" lathe is something like this... shipping cost for that mini monster can result you in cost of $1000 or more in total... even that mini machine has quirks when reviewed in the net, repairing it requires you to have more bigger lathe/mill cost an arm... anything less than this is a toy imho, even this can be classified as toyish grade... Mini Lathe Machine WM210V Small Household Lathe with 600W Motor secondly it requires large amount of space or extra if you have both of this lathe and cnc separate, esp if you only do some miniaturized devices...


« Last Edit: September 22, 2019, 04:28:33 am by Mechatrommer »
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Offline 3dgeo

  • Regular Contributor
  • *
  • Posts: 184
  • Country: au
Re: Right motors, PSU for CNC mill
« Reply #36 on: September 22, 2019, 04:28:31 am »
the fets on the stepstick are 12A and ~6mOhm apart from the 40V rating much more than that would be pointless
Yep, 40V is a deal breaker, tho I'll probably end up buying both bards for testing their coding.

breaking out the pins take space and even more if they have to go to a reasonable connector
It's a 4 layer board and it looks pretty empty – just admin you were lazy :D

the choice between rails and aluminium with wheels is the choice between cheap and good
Thing is I don't think Cbeams are bad :D Tho I might be wrong...

and if you look at his later videos he is using mgn12 an ballscrews in his latest design
Yes, sadly he did not explained the difference and his reasoning

everything complicated is going to be a pain to program, but it the little I've looked at it it seems the documentation on the TMC is better
I'm not afraid of complexity, I'm afraid poor support/documentation on the matter.

Thank you for your time and answers, now I have to do more digging and make a choice...



Mechatrommer – Google "mini wood lathe" and you'll find what I had in mind.
« Last Edit: September 22, 2019, 04:34:31 am by 3dgeo »
 

Offline Mechatrommer

  • Super Contributor
  • ***
  • Posts: 9067
  • Country: my
  • reassessing directives...
Re: Right motors, PSU for CNC mill
« Reply #37 on: September 22, 2019, 04:54:00 am »
Mechatrommer – Google "mini wood lathe" and you'll find what I had in mind.
lathing "wood only" is not what i have in mind.
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf