I NeeD HeLp PLease AM882 a good choise

[Jonathan]

I have a couple of questions regarding the hgr15 for the x axis, maybe they will work or will I need a hgr20?

Either is plenty stiff enough. Sometimes people go for the 20mm rails just to make it easier to to make the parts they mount to with minimal machining. You need to draw it and work out which is best before buying them.

Motors
5PCS Nema 23 stepper motor 425oz-in,3A,2ph,1.8° CNC Engrave 241uss

Don't get those. They're 3A/phase which means they're the higher inductance motors. You want motors with lower inductance to get more torque at higher speeds - just search this on the forum and you'll find more detailed explanations. Last time I checked, these were the best value.

Timming Belts?
Witch timing belts and pulleys do you recommend?

HTD 5m (i.e. 5mm pitch) and 15mm belt width. Don't get bigger pulleys than you need to as it'll adversely affect the acceleration. You can get them from Bearing Station, belting online or aliexpress.

Drivers and supply power?
I have the same problem as before, I believe that you can help me with this. I have researched on these products, what do you think? Is it an analogic driver convenient or a digital one?

The 'digital' ones should be better than the 'analogue' ones, but it's a bit of a misnomer as they're all digital to an extent. Drivers like the AM882 use better algorithms (e.g. field oriented control) to get slightly higher torque from the motors and detect stalling, among other things. However once you've tuned the system properly it wont stall, so if you can get enough torque with a cheaper driver (e.g. DQ860MA) I see no reason to get the better ones.

[JAZZCNC]

I see no reason to get the better ones.

I see a reason.!!!!. . . . They are better.!! . . . and the price difference is not enough to justify not taking advantage of there more advanced features like better resonance handling and stall detect. Has you well now there are other things beside incorrect tuning which can stall motors and on dual screw machine having the ability to alert and E-stop the machine is worth the slight extra cost IMO.

Oh and from the few times I've used the DQ869MA the AM882 give much smoother performance from the motors at lower feeds.!!

[EddyCurrent]

Juan,
Have a read on this thread about the frame design.

http://www.mycncuk.com/forums/router...-please-3.html

[Jonathan]

I see a reason.!!!!. . . . They are better.!! . . . and the price difference is not enough to justify not taking advantage of there more advanced features like better resonance handling and stall detect.

Just because something that it better is available doesn't mean you need something better. The machine will run perfectly well with DQ860MA drivers.
The cheapest AM882 drivers on aliexpress are currently £56.18 each, versus £37.65 for the DQ860MA. In my opinion it's not worth the extra £18.26 when the machine will be fast enough with either.
If concerned about stalling, then by all means get two AM882 drivers for the X-axis, but save £36.50 and get cheaper ones for Y and Z.

[JAZZCNC]

In my opinion it's not worth the extra £18.26 when the machine will be fast enough with either.
If concerned about stalling, then by all means get two AM882 drivers for the X-axis, but save £36.50 and get cheaper ones for Y and Z.

Nope sorry don't agree at all.!! . . . . Told you before It's not all about speed and the Am882 are so much smoother it's worth paying £18 just for that IMO without all the other advanced features. Why have a lesser machine when for just few quid more it can be all it can be.?

[EddyCurrent]

@Jonathan, I agree there is no need to buy more than you require and I'm not an expert on all the different drivers but for £36 I'm not taking any chances. I once read somewhere a long time ago about a bloke buying power tools, he said he found it always paid to select the model you could afford then buy the next model up.

[jpsicilia]

Thanks for help me guys, really.
I bought the screws today, one less thing. Jonathan I can only buy in aliexpress and eBay, I could not find the nema23 you recommended, I have looked similar but I dont know what I need to look about the inductance, could you tell me what models I shoud look.
And about the Linear Motion they offer me a similar exchangeable for u$s 622 usd instead of the hgr15 for 850 uss, what do you think? should buy it or go for hgr15?

[Jonathan]

I bought the screws today, one less thing. Jonathan I can only buy in aliexpress and eBay

Then you're basically stuck if you want them for a reasonable price. Will CNC4YOU not ship to your country? If not, then you need to find 3Nm (425oz-in) motors with 3.2mH phase inductance. They generally have 4.2A current rating.

And about the Linear Motion they offer me a similar exchangeable for u$s 622 usd instead of the hgr15 for 850 uss, what do you think? should buy it or go for hgr15?

It sounds like they're offering you a different brand of rail, e.g. LG or TBI, which is probably fine. Not many people here have bought them yet, so it's hard to compare the quality and even then the differences are likely to be so small it's hard to quantify. The TBI brand rails I got from aliexpress seem fine, so next time I need some I doubt I'll get Hiwin.