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jonm
18-07-2009, 11:02 PM
hi all
been reading this forum now for a while, picking things up from you guys and i am now ready to start my build which will be a wood router , i have ordered from zapp 3 nema 24 3nm steppers, 2 1200mm long fully supported 16mm round rail 4 open bearings . going to use 12mm trapeziod 3mm pitch for drive , i have a block of derlin from ebay to make nuts , and have made a tap from a piece of trapeziod, slowly gathering parts together, would 2.5 amp drivers be enough or do i need 4 amp, the attachment is a section through the x axis would this work , i would like to make the y axis stiff enough so as to drive the x axis from one side only , any help would be appreciated

Gary
19-07-2009, 11:12 AM
the SY60 will run from either 3A in unilpolar, 2.1A in series (Bipolar) or 4.2A in Parallel (Bipolar)
So the answer is yes the motors will run in series with a 2.5A driver, but dont expect to get the machine running very fast, unless you connect in parallele and give it at least 40V.
I doubt you will be able to run from the center, even with a stiffer machine using profiled rail can crab, and you are using MDF and this will cause you big problems.
Even running the screw through the center will still casue you problems.



hi all
been reading this forum now for a while, picking things up from you guys and i am now ready to start my build which will be a wood router , i have ordered from zapp 3 nema 24 3nm steppers, 2 1200mm long fully supported 16mm round rail 4 open bearings . going to use 12mm trapeziod 3mm pitch for drive , i have a block of derlin from ebay to make nuts , and have made a tap from a piece of trapeziod, slowly gathering parts together, would 2.5 amp drivers be enough or do i need 4 amp, the attachment is a section through the x axis would this work , i would like to make the y axis stiff enough so as to drive the x axis from one side only , any help would be appreciated

HiltonSteve
19-07-2009, 12:17 PM
I doubt you will be able to run from the center, even with a stiffer machine using profiled rail can crab, and you are using MDF and this will cause you big problems.
Even running the screw through the center will still casue you problems.

Have to agree with Gary here, using open bearings will always cause you crabbing problems which is why I dismissed them for my design, but driving from both sides will soon sort that out.

Though, I have built up my X axis gantry yesterday on my machine which has a bed size of 1000mm x 600mm and using 20mm THK linear bearings gets virtually no crabbing, I will be driving this machine from the centre. It is a pretty solid all aluminium machine which does help though. will get a clock gauge on it later to measure it but it is not a lot.

Gary - Don't forget to send me those 16mm ballnuts when they come in, they are the only piece missing now before I can get up and running.

Gary
19-07-2009, 12:34 PM
The ball nuts leave the factory on the 20th so i expect them to arrive mid week (Wednesday / Thursday.)


Have to agree with Gary here, using open bearings will always cause you crabbing problems which is why I dismissed them for my design, but driving from both sides will soon sort that out.

Though, I have built up my X axis gantry yesterday on my machine which has a bed size of 1000mm x 600mm and using 20mm THK linear bearings gets virtually no crabbing, I will be driving this machine from the centre. It is a pretty solid all aluminium machine which does help though. will get a clock gauge on it later to measure it but it is not a lot.

Gary - Don't forget to send me those 16mm ballnuts when they come in, they are the only piece missing now before I can get up and running.

HiltonSteve
19-07-2009, 12:45 PM
The ball nuts leave the factory on the 20th so i expect them to arrive mid week (Wednesday / Thursday.)


Nice one!

May be up and running by next weekend then.:biggrin:

jonm
19-07-2009, 04:47 PM
thanks for the input guys , may bin the mdf idea seen aluminium herehttp://www.aluminium-profile.co.uk/acatalog/Aluminium_Profile_with_10mm_Slot.html

could get a frame for about 60 ,would it crab with 2 bearings per rail spaced say 200mm , could i run two skate bearings against the outside of the frame on the non driven side to keep it parallel and stop the racking , i have aready ordered the 16mm rails from zapp

HiltonSteve
19-07-2009, 04:59 PM
I would still say drive it from both sides, just get another motor and trapazoidal screw and it will be a much better solution. It may cost you a little bit more but at least you know it will be right!

Just wire both motors to the same driver card, so you won't need to spend more on electronics.

Gary
19-07-2009, 05:54 PM
I dont suggest connecting both motors to the same driver.
This can cause problems with the driver and will also void the warrantee of the driver.
As an example of the problems you will see is that if the driver has any anti resonance circuitry this will most likely cause this to not function as expected.
You will also have issues with BEMF.



I would still say drive it from both sides, just get another motor and trapazoidal screw and it will be a much better solution. It may cost you a little bit more but at least you know it will be right!

Just wire both motors to the same driver card, so you won't need to spend more on electronics.

jonm
19-07-2009, 06:55 PM
thanks hilton steve
will gladly take your advice and go for twin screws , i dont want to waste time and money and end up with a machine that
needs.... well more time and money !! . this, by the way is a great forum for information

Smiler
19-07-2009, 07:08 PM
thanks hilton steve
will gladly take your advice and go for twin screws , i dont want to waste time and money and end up with a machine that
needs.... well more time and money !! . this, by the way is a great forum for information

If you go with twin screws, I'd drive them both via belt from a single motor. If you use two motors and slave one to the other and one loses steps you will get racking. If one stalls, you could get a broken machine.

My 2 penneth'

Jeff.

Gary
19-07-2009, 08:31 PM
What documentation? would be interested in having a look at that.
When i was technical director at mcp it was policy to strongly advise not to use two motors with one driver.




Although I have documentation from MCP suggesting my drivers are powerful enough to drive 2 motors.....

HiltonSteve
19-07-2009, 10:19 PM
To be honest I have never tried driving 2 motors from 1 driver, I was thinking about doing this in my initial design stage because someone suggested it but gave up on the idea.

Well you learn something every day!

John S
19-07-2009, 11:05 PM
So have I, shed loads of it, tried to sell some to you :yahoo:

.

John S
19-07-2009, 11:51 PM
Kip, got two 6' lengths of about 8DP rack, no pinions that's only suitable for a gate or similar you can have.

BTW saw a gate mechanism, home made that used one of those motorised liner ballscrew assemblies. He'd mounted the fixed point behind the pivot point in X and Y to be technical so it had a mechanical advantage and the 10" or so travel was enough to swing a big 5 bared gate.

Gary
20-07-2009, 10:50 PM
I wrote that and it is meant as wiring the motor in parallel. like wiring the four phases in parallel or series, not more than one motor in parallel.
I Understand why it can sound ambiguous.


Just looked (still on the site) it's more an ambiguity I think... "and the drivers are powerful enough to connect the motors up in parallel for faster motion"

HiltonSteve
24-07-2009, 01:46 AM
The ball nuts leave the factory on the 20th so i expect them to arrive mid week (Wednesday / Thursday.)

Attn - Gary - Zapp Automation

Sorry to hijack the thread again but I really need my ballnuts now...

Have you got them in yet and any idea on delivery?

Gary
24-07-2009, 07:25 AM
They were sent to you the other day, so you should get them today.

Attn - Gary - Zapp Automation

Sorry to hijack the thread again but I really need my ballnuts now...

Have you got them in yet and any idea on delivery?

HiltonSteve
24-07-2009, 12:12 PM
They were sent to you the other day, so you should get them today.

Sitting here with my nuts in my hand...!!

Delivered this morning just as you said, nice one Gary.

John S
24-07-2009, 02:23 PM
So where's the pics of the finished machine ?
.