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?
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.