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View Full Version : Two ball screws for my x axis and two motors, do i need two drivers?



luke11cnc
10-08-2011, 11:47 AM
OK my cnc machine is well on it's way

I do have a question

I am using two ball screws for my x-axis and two motors

so my question is this

will I need two drivers for this and then if so where can I get a 5-axis system kit from under two hundred & seventy pounds?

like this but 5-axis
http://www.diycnc.co.uk/html/cnc_systems.html

is it cheaper to buy the breakout board and drivers and make it my self

will I need two power supplies and break out boards?

what cables do I need?

this is getting confusing as I don't do electronics :confused::confused:

James & Luke

Jonathan
10-08-2011, 12:38 PM
Definately two drivers with two motors. It's theoretically possible to do it with one ... but don't go there!

Those drivers are not very good at all - only 27 volts. You should get at least 50V, or 75V. That will be more like 200 for the drivers and something for the breakout board ... there's a cheap 5-axis one on eBay.

One breakout board will suffice, unless you run out of inputs later on. You just need as many power supplies as required to get sufficient power to the motors. I used a 500VA, 75V (when rectified) transformer for 4 motors ... it's ok on 5 too.

CY, 4-core cable 1.5mm^2.

Don't worry about the electronics, I'm sure I/we can assist...

luke11cnc
10-08-2011, 12:43 PM
ok Jonathan where do i order the drivers from

James

wiatroda
10-08-2011, 03:46 PM
Divers from http://www.slidesandballscrews.com (http://www.slidesandballscrews.com/) and try this one PM752 Microstepping Driver

Transformer and electronics from http://uk.farnell.com (http://uk.farnell.com/)
At least I bought there :)

Jonathan
10-08-2011, 04:18 PM
PM754 from Zapp is good - that's where I got them, but now there's cheaper available on eBay:

http://www.ebay.co.uk/itm/5-2A-70V-Stepper-driver-CNC-Milling-machine-router-/320737706080?pt=UK_BOI_Industrial_Automation_Contr ol_ET&hash=item4aad750060#ht_763wt_905

http://www.ebay.co.uk/itm/4-Axis-Stepper-motor-driver-PEAK-4-2A-18-50VDC-CNC-New-/270737739534?pt=LH_DefaultDomain_0&hash=item3f093a0f0e#ht_4174wt_997

http://www.ebay.co.uk/itm/3-Axis-CNC-Stepper-Driver-80VDC-8-2A-replacing-MD882-/170677340791?pt=LH_DefaultDomain_0&hash=item27bd298a77#ht_2915wt_905

http://www.ebay.co.uk/itm/CNC-Stepper-Motor-Driver-controller-2M982-7-8A-Driver-/270727089502?pt=LH_DefaultDomain_15&hash=item3f08978d5e#ht_3679wt_905

(those are not necessarily the cheapest, so do have a look yourself)

Transformer: Farnell good, eBay better if you're lucky...
I've got some capacitors / bride rectifiers so if you do get a transformer I can sort the rest of the bits.

wiatroda
10-08-2011, 04:36 PM
PM754 from Zapp is good - that's where I got them, but now there's cheaper available on eBay:

cnc-parts4u (http://stores.ebay.co.uk/cnc-parts4u?_trksid=p4340.l2563) I'm preety sure that's Zapp in another incarnation :)

Jonathan
10-08-2011, 06:09 PM
cnc-parts4u (http://stores.ebay.co.uk/cnc-parts4u?_trksid=p4340.l2563) I'm preety sure that's Zapp in another incarnation :)

Suspiciously similar isn't it. Sill not the cheapest in England for drivers. Can't fault them on their service though.

luke11cnc
10-08-2011, 07:22 PM
I think I'm going to buy this set up as it has two extra drivers (spare or extra axis if needed)

http://www.ebay.co.uk/itm/6Axis-CNC-Controller-Step-Driver-24-80VDC-7-8A-256Micr0-/180601095209?pt=LH_DefaultDomain_0&hash=item2a0caa0429#ht_3337wt_905

but still unsure if it's the right think to buy

James

jcb121
10-08-2011, 07:24 PM
it is the same, I've ordered steppers from Ebay and asked if i could have something from Zapp as well but it was out of stock!

Get some pics up mate!! I wanna see a proper build log to base mine on! :P

Jonathan
10-08-2011, 07:42 PM
I think I'm going to buy this set up as it has two extra drivers (spare or extra axis if needed)

http://www.ebay.co.uk/itm/6Axis-CNC-Controller-Step-Driver-24-80VDC-7-8A-256Micr0-/180601095209?pt=LH_DefaultDomain_0&hash=item2a0caa0429#ht_3337wt_905

but still unsure if it's the right think to buy

James

Good find - they are the right thing to buy. It would be interesting to compare them to the PM752 - theoretically they should work just the same on 75V, but you never know.

Optoisolated breakout board with drivers that are already isolated can cause problems if you don't wire it right. Don't worry about it though, I'm sure it'll be fine.

luke11cnc
10-08-2011, 08:05 PM
jess I will put up images when my parts come

ball screws and rails are in Paris so should be here any day

James

jcb121
10-08-2011, 08:34 PM
aye, mine were in paris last night and came today! 4 days delivery isn't bad!

Also, I spent over 500 and didn't get charged a penny of import tax/handling fee :)

that's a win right there.

I'm looking forward to how yours comes out.

Jonathan
10-08-2011, 08:41 PM
Also, I spent over 500 and didn't get charged a penny of import tax/handling fee :)


Not yet anyway. They wait a couple of weeks to make you feel happy then you get the letter.
What was the value quoted on the parcel?

Going to try milling some steel on my router now ...

m_c
10-08-2011, 09:57 PM
Can't beat the old wait one week, then give you the bill routine.

The customs charges don't really bother me, it's the handling charges that do.
Although a fender who makes mistakes filling in the customs value can be helpful ;-)

Jonathan
10-08-2011, 11:43 PM
The customs charges don't really bother me, it's the handling charges that do.
Although a fender who makes mistakes filling in the customs value can be helpful ;-)

Couldn't agree more with both those statements. Well, ignoring the typo that is!

Peter.
11-08-2011, 05:47 AM
I think I'm going to buy this set up as it has two extra drivers (spare or extra axis if needed)

http://www.ebay.co.uk/itm/6Axis-CNC-Controller-Step-Driver-24-80VDC-7-8A-256Micr0-/180601095209?pt=LH_DefaultDomain_0&hash=item2a0caa0429#ht_3337wt_905

but still unsure if it's the right think to buy

James

Misleading advert though. THe description seems honest enough but they have put pictures of stepper motors in as if they are included, when the auction is for just the electronics.

luke11cnc
11-08-2011, 01:19 PM
I disagree peter
yes their are images of motors but the text does say drivers and break out board

Jams

Peter.
11-08-2011, 01:56 PM
Well, the pictures form a large part of the description for many people. Some are not so good at reading and rely on them heavily. I think if they are not included they should either not be in the picture or it should say quite clearly - stepper motors not included.

Jonathan
11-08-2011, 02:48 PM
Misleading advert though. THe description seems honest enough but they have put pictures of stepper motors in as if they are included, when the auction is for just the electronics.

Don't see the problem, you've noticed it's just the drivers and breakoutboard so you've not been mislead. The rest is clearly there for advertising.


Well, the pictures form a large part of the description for many people. Some are not so good at reading and rely on them heavily.

They should read the description. Pretty sure that's in the eBay policy somewhere...if you can't read then you're probably not going to be buying stepper drivers anyway!


I think if they are not included they should either not be in the picture or it should say quite clearly - stepper motors not included

It says clearly what is included so surely it's natural to assume the rest is not?

Peter.
11-08-2011, 03:18 PM
Of the eight pictures included in the auction only two apply to what's being sold. The others have been included, some showing nothing that's included in the auction. I don't think that it would be at all natural to assume they are not included and someone could easily be fooled into thinking they were. It's just not right to be padding-out auctions with images of stuff not included.

We have a difference of opinion - no big deal, I didn't intend to ruffle any feathers.

luke11cnc
12-08-2011, 01:21 AM
ball screw

how is the bearing supports attached to the ball screw

the thin one goes on the end ??
the thicker bearing support goes on the stepper motor end ?? and the threaded nut keeps the bearing in place

I would like to know if this is correct

James

Jonathan
12-08-2011, 01:26 AM
Yes that's right. The threaded nut (never seen a nut that's not threaded, except the edible variety!) clamps the inner ring of the double angular contact bearing to the screw. The purpose of this is to eliminate axial play in the screw, though strictly speaking double row angular contact bearings have some clearance so it's not perfect.

The other end has a single standard bearing to support the end of the screw radially and allow it to expand/contract due to temperature changes.

luke11cnc
12-08-2011, 01:32 AM
it's just that they are really tight so I will have to use a rubber mallet ?? is this normal

James

Jonathan
12-08-2011, 01:42 AM
it's just that they are really tight so I will have to use a rubber mallet ?? is this normal

No, sounds like the end machining for the bearings might be a bit oversize. Don't use a mallet as that will damage the bearings unless you can only hit the inner ring of the bearing... could try heating up the bearing to make it expand a little. It would be best to measure them with a micrometer first just to be safe as you don't want the bearing to get stuck half way.

luke11cnc
12-08-2011, 01:44 AM
jonathan

I will bring it with me when I collect my brackets to see what you think if thats ok

James

Jonathan
12-08-2011, 01:54 AM
Yes that's fine, we can measure it and try another bearing in case it's the bearings at fault.

luke11cnc
12-08-2011, 01:55 AM
cool thank you so so much

James