New build with recycled parts on a ridiculous budget 120cm*60cm work area

[Clive S]

If I find them underpowered (3 of them are 2nm and the one on the Z axis is 1.6nm) I'll replace 3 of them for the X&Y with 8 wire nema 3nm+ nema 23's and swap one of the 2nm onto the Z axis.

i think that they will be under powered especially if you are using R & P

[Desertboy]

i think that they will be under powered especially if you are using R & P

I'm using 1604mm ballscrews (twin) on the Y, and 1605 on the X and Z. I want to build an 8*4 soonish and I think I'd like to use R&P on that for speed but since then I found you can buy commercial 8*4 routers relatively cheaply at auction or on ebay which make building one a lot less attractive.

When I bought the ballscrews I didn't know what 1604 and 1605 meant lol in retrospect I would have gone with 2010's as the price difference wasn't a lotbut then of course I definitely need the bigger motors I see cnc4you do a 4nm nema 23

https://www.cnc4you.co.uk/Stepper-Mo...-03-x-3-Nema23

I wonder if I bought 3 of these (6amp) and swapped one of my 2nm motor's (3amp) to the Z axis will 1 650va toroidal transformers be enough? If I did it I'd swap the ballscrews over to 10mm pitch to double the speed. It's unlikely I will try to mill much aluminium on this but if I do I won't be doing it in the middle lol I'll do it at the edges closest to the Hiwin's to reduce flex on the gantry.

[Clive S]

https://www.cnc4you.co.uk/Stepper-Mo...-03-x-3-Nema23

I wonder if I bought 3 of these (6amp) and swapped one of my 2nm motor's (3amp) to the Z axis will 1 650va toroidal transformers be enough? If I did it I'd swap the ballscrews over to 10mm pitch to double the speed. It's unlikely I will try to mill much aluminium on this but if I do I won't be doing it in the middle lol I'll do it at the edges closest to the Hiwin's to reduce flex on the gantry.

IN my opinion that would be fine.

[Desertboy]

Looking through the AM882 manual I found this interesting

"6. Power Supply Selection
The AM882 can match medium and small size stepping motors (from NEMA frame size 14 to 34) made by Leadshine or other motor manufactures around the world. To achieve good driving performances, it is important to select supply voltage and output current properly. Generally speaking, supply voltage determines the high speed performance of the motor, while output current determines the output torque of the driven motor (particularly at lower speed). Higher supply voltage will allow higher motor speed to be achieved, at the price of more noise and heating. If the motion speed requirement is low, it’s better to use lower supply voltage to decrease noise, heating and improve reliability.


Regulated or Unregulated Power Supply
Both regulated and unregulated power supplies can be used to supply the drive. However, unregulated power supplies are preferred due to their ability to withstand current surge. If regulated power supplies (such as most switching supplies.) are indeed used, it is important to have large current output rating to avoid problems like current clamp, for example using 4A supply for 3A motor-drive operation. On the other hand, if unregulated supply is used, one may use a power supply of lower current rating than that of motor (typically 50%～70% of motor current). The reason is that the drive draws current from the power supply capacitor of the unregulated supply only during the ON duration of the PWM cycle, but not during the OFF duration. Therefore, the average current withdrawn from power supply is considerably less than motor current. For example, two 3A motors can be well supplied by one power supply of 4A rating.

Multiple Drives
It is recommended to have multiple drives to share one power supply to reduce cost, if the supply has enough capacity. To avoid cross interference,
DO NOT daisy-chain the power supply input pins of the drives. Instead, please connect them to power supply separately.

Selecting Supply Voltage
The power MOSFETS inside the AM882 can actually operate within +20 ~ +80VDC, including power input fluctuation and back EMF voltage generated by motor coils during motor shaft deceleration. Higher supply voltage can increase motor torque at higher speeds, thus helpful for avoiding losing steps. However, higher voltage may cause bigger motor vibration at lower speed, and it may also cause over-voltage protection or even drive damage. Therefore, it is suggested to choose
only sufficiently high supply voltage for intended applications, and it is suggested to use power supplies with theoretical output voltage of +20 ~ +72VDC, leaving room for power fluctuation and back-EMF. "

I take it I'm building an unregulated PSU?

[Clive S]

I take it I'm building an unregulated PSU?

Yes if you followed the links I posted

[Desertboy]

Yes if you followed the links I posted

Going to buy the bits you linked to from rapidonline ;)

I'm reading Joe's excellent thread right now but started at the beginning of the thread so taking a while to get to the PSU posts but I think I've got it sorted in my head had a good read around other sites and it seems really simple.

Transformer steps down the voltage, bridge rectifier converts it to DC, capacitors smooth out the DC more capacitors smoother DC.

Looking for a suitable terminal block like Joe has I found them on ebay but take too long from China so need to find a UK equivalent.

e2a found some
https://www.rapidonline.com/truconne...-block-21-3073

[Desertboy]

Clive S would it be worth getting a pci parallel port and a 2nd breakout board? Cost is only £15 for both. I have no idea how to wire up and configure one board never mind 2 lol.

:)

Ordered bits for power supply £90 in the end

I got the 25v transformer you linked to Clive only 1 left now ;) I also got 4 capacitors instead of 3, capacitor holers, some barrier terminal connectors, bridge rectifier and 5m of red wire, 5m black wire 2.5mm core.

Now I have no excuse not to have the power supply working before the drivers come.

Had to order 3 more sets of bolts to finish building the router they will be here Friday most of the Z axis is built up now my travel is pitiful around 7cm. If I remake one of the Z axis plates I can get almost 17cm of travel so will do that shortly need to score some 20mm thick tooling plate don't fancy paying £15 delivery on £8 of tooling plate lol.

7cm is actually more than enough for what I plan with the machine but might as well get the extra travel sorted sooner than later and an interesting early project for my machine.

They've shipped everything except my cabling which will be a week :(

That's really annoying eyeing up my heated bed on the 3d printer that has 2.5mm wire and would give the excuse to swap the red mk2 heated bed to the mk3 I got ages ago but never wired up.