Planning on a build: how to select a good driver+motor combo?

[Noplace]

Hi, so I'm planning on designing my own 2.5D mill and just reading up on the electronics atm, I'm planning on building something robust so I'm taking my time in selecting parts.
so first question is how to decide the power of my motors? just based on size + weight of spindle+gantry or how is it calculated/determined exactly?
second, for the said motors whats the best driver i can buy and not cost an arm and a leg, someone here was suggesting http://www.zappautomation.co.uk/electrical-products/stepper-drivers/em-high-performance-stepper-driver-step-direction/em806.html[1] for one of the builds
would you recommend me getting that for a machine I'm planning on building and using for a long time?

oh and also which cable size should i stick to?

my plan is to build something with a work area of around 1000x600x200mm (a little less or a little more doesnt matter to me)

Thank you!

[mitchejc]

Hi, you can maybe have a look at this link, there's a handy spreadsheet that will help with getting an idea of the stepper size required
http://www.mycncuk.com/threads/1524-What-size-stepper-motor-do-I-need?highlight=stepper+sizing

[Boyan Silyavski]

Basically the all around best combo is Toroid PSU 70V 550-600W , High voltage drivers like AM822, 3NM low inductance motors like SY60STH86-3008B Nema 23 (http://www.zappautomation.co.uk/electrical-products/stepper-motors/nema-23-stepper-motors/sy60sth86-3008b-nema-23-stepper-motor.html)


The most economical way to build that is to buy the transformer/2x50v AC wired in parallel (http://www.ebay.es/itm/171058196205?var=470261076956&ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649) or 2x25V AC in series >550W for 4 motors/, then power regulator board with big capacitors (http://www.ebay.es/itm/130780318790?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649) from ebay to rectify it, the drivers from China aliexpress and the motors from Zapp.

0.8mm /18AWG cables 4 core shielded (http://www.ebay.es/itm/2424C-SL005-Alpha-Wire-Cable-Shielded-18Awg-4-Core-30-5-Metres-/131346457203?pt=UK_BOI_Electrical_Components_Suppl ies_ET&hash=item1e94dbe273) for the motors. I would use the same cable for the sensors and stuff. Easy to solder and strong. My first build i used thin alarm cable that alarmingly f@@@ed up. So just buy 1 entire roll is my advice.

Assuming you don't make a heavy gantry >80kg, for 1:1 driven i mean. Most of the people go with 1610 ball screw on all axis and 1605 on Z , That makes fast and and the same time with good resolution machine.

20T HTD 15 pulley is the most used, 1:1, the belts used are in the 250-310mm length area. 15mm wide , beltingonline.com

SY CABLE CLEAR SHIELD BRADED 1.5mm 4 CORE (http://www.ebay.es/itm/SY-CABLE-CLEAR-SHIELD-BRADED-1-5mm-4-CORE-CUT-TO-REQUIRED-LENGTH/261732828282?_trksid=p2047675.c100011.m1850&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%2 6asc%3D20140620074313%26meid%3D73a4b571ea7d4634a2c 811bd8005cfbf%26pid%3D100011%26rk%3D1%26rkt%3D2%26 sd%3D251316543395) cable for the spindle to VFD


And so on :encouragement:

[Noplace]

thanks for the info! offtopic question if you dont mind, I've been looking at ball screws, found some at automation4less.com which looks like a decent site but the prices for the screws and its parts is kinda steep, I did find on ebay also from chinese sellers, question is does it matter which one I pick in quality or are the chinese good enough ?

[EddyCurrent]

The sellers listed here seem to be the most popular, I think the Chinese stuff is fine, many people here use it.

http://www.mycncuk.com/threads/8189-ball-bearings-in-a-ball-nut-how-many?p=64544#post64544

[Boyan Silyavski]

yes, it matters i believe. Like Eddy says- Linearmotion bearing, solar jean . I buy from BST automation /aliexpress/ - Fred. He has all, from drivers to ball screws, same price as Chai and overall very good experience. Good at fixing mistakes also. The machining is 0.01mm spot on.