Electronics > Projects, Designs, and Technical Stuff

Right motors, PSU for CNC mill

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3dgeo:

--- Quote from: Mechatrommer on September 17, 2019, 05:07:37 am ---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?

--- End quote ---
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.


--- Quote from: Mechatrommer on September 17, 2019, 05:07:37 am ---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.

--- End quote ---
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


--- Quote from: Mechatrommer on September 17, 2019, 05:07:37 am ---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.

--- End quote ---
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




--- Quote from: langwadt on September 17, 2019, 09:07:43 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

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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...

langwadt:

--- Quote from: 3dgeo on September 20, 2019, 11:22:45 pm ---

--- Quote from: langwadt on September 17, 2019, 09:07:43 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

--- End quote ---

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...

--- End quote ---

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

Mechatrommer:

--- Quote from: 3dgeo on September 20, 2019, 11:22:45 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

--- End quote ---
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.

SparkyFX:
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.

3dgeo:

--- Quote from: langwadt on September 21, 2019, 10:34:02 am ---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

--- End quote ---
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?


--- Quote from: langwadt on September 21, 2019, 10:34:02 am ---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

--- End quote ---
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.



--- Quote from: Mechatrommer on September 21, 2019, 12:05:23 pm ---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.

--- End quote ---
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...

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