Designing rock solid printer - AXIS drive help

Hi all,

I was after some community input on one simple, but big decision on my next 3d printer build. I am designing a 3d printer that I plan on being very good, as in using more metal parts for a more rigid build and using SC10UU bolted to carriages RATHER than LM8UU bearings zip tied to printed carriages. I am copying many aspects of the Stratasys uPrint SE Plus printer. (I have one in my workplace, so I have access to extensively study its structural design.)

XY Axis at the top of the frame, Z axis moves down (same as ultimaker makerbot etc)

The decision I am currently having trouble to come to a conclusion is how the Y axis will be driven.

In the makerbot and ultimaker the Y axis is driven by a nema 17, with a closed belt, driving the rotation of a long smooth rod which has two more pulleys on it driving both sides of the Y axis.

Examples:
In the background of this image: [thingiverse-production.s3.amazonaws.com]

A better example: [ultimaker.ipbhost.com]

So, this seems to be the more common way these printers have their axis driven, but is it the better way?

The alternative being having a Nema on each side of the axis, (like is done for Z in prusa i3)

Can be seen in both these videos:
[www.youtube.com]
[www.youtube.com]

So, If you ignore the extra cost of a second Nema and ignore the more tedious wiring job of a second motor, which would have more precision, because my end goal is a EXCELLENT performing self designed printer, not something that is nesacarily cost effective.

Always appreciate your input, sorry for the bad explaining of each type of axis drive but bad explanation is just me

Thanks for viewing.

-stustu242

Quote
stustu242
Hi all,

I was after some community input on one simple, but big decision on my next 3d printer build. I am designing a 3d printer that I plan on being very good, as in using more metal parts for a more rigid build and using SC10UU bolted to carriages RATHER than LM8UU bearings zip tied to printed carriages. I am copying many aspects of the Stratasys uPrint SE Plus printer. (I have one in my workplace, so I have access to extensively study its structural design.)

XY Axis at the top of the frame, Z axis moves down (same as ultimaker makerbot etc)

The decision I am currently having trouble to come to a conclusion is how the Y axis will be driven.

In the makerbot and ultimaker the Y axis is driven by a nema 17, with a closed belt, driving the rotation of a long smooth rod which has two more pulleys on it driving both sides of the Y axis.

Examples:
In the background of this image: [thingiverse-production.s3.amazonaws.com]

A better example: [ultimaker.ipbhost.com]

So, this seems to be the more common way these printers have their axis driven, but is it the better way?

The alternative being having a Nema on each side of the axis, (like is done for Z in prusa i3)

Can be seen in both these videos:
[www.youtube.com]
[www.youtube.com]

So, If you ignore the extra cost of a second Nema and ignore the more tedious wiring job of a second motor, which would have more precision, because my end goal is a EXCELLENT performing self designed printer, not something that is nesacarily cost effective.

Always appreciate your input, sorry for the bad explaining of each type of axis drive but bad explanation is just me

Thanks for viewing.

-stustu242

Have you considered CoreXY have a look in the COREXY subforum

Hi. IMO, there's no need to have a dual motor drive on any axis. On the Mendel style printers (like the I3) the two motors makes X leveling more simple, just ofset a threaded rod and you're level with the bed. The core XY makes distant driving points work together with a single stepper motor. Anyways, if an axis is stiff enough and properly guided, one motor is enough to drive it.

If you want a very good printer, may I suggest to give up unsupported linear guides ? 10mm instead of 8mm does not make a huge difference. The rod is a bit stiffer, but it can oscilate as well, and the linear bearings introduce some gap, even into aluminium bushing, because you cannot load that kind of bearings, You do with the existing gap in the bearing. Even with some SFK hi quality, pre-loaed (and expensive) linear bearings, you can't stop the rods to wobble. Especialy with repetitive short forward and reverse movements.

Depending of the design you'll choose, you can go for supported linear rails, like SBR10, or much better, Hiwin miniature MG series (or into other brands SFK, NSK, INA, Bosch...). The quality of miniature linear rails is that good that you can drive a 3D axis with a single rail and carriage. That would be my choice for a high quality printer.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Quote
Zavashier
Depending of the design you'll choose, you can go for supported linear rails, like SBR10, or much better, Hiwin miniature MG series (or into other brands SFK, NSK, INA, Bosch...). The quality of miniature linear rails is that good that you can drive a 3D axis with a single rail and carriage. That would be my choice for a high quality printer.

Hi Zavashier, Thanks for your valuable input.

I had a brief look into these branded linear motion options, and may I ask, is it possible for me to order these parts or is this for businesses making larger orders only? Because there isn't a way to purchase these items like it were a shop, more like a place where a product description is given, but no order details or prices. (e.g. hiwin, SFK etc) I have found many suppliers of SBR10UU bearings and rods, do you think these are a better option than standard unsupported rods?

Finally, I have had a look into solutions like maker slide and Vslot.

[openbuildspartstore.com]

What do you think of these alternatives?

Thanks for your time, its appreciated.

The V groove rails and bearings is a good option. Just remember it's only 20mm profile with 1.8mm thickness, that cannot stand long distance and/or too heavy loads. You can even take the Vgroove mini weels if you like, that will be pretty enough for our printer's purpose. The supported rails are ways better than unsupported ones, except in traction mode (I mean opposite direction of the support). But it's not a factor because you can mount them back to back to counterbalance that weakness. Otherhand, linear rails, like Hiwin's have no weak point. It's possible to order them on Aliexpress.com, there's kossel kits at reasonable price. Anyways, Openbuilds is surely a less expensive working solution. Be sure to take the good profile width for your design.

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

It sounds similar to my 'work in progress' build.
I went for a X-Y at the top with an elevating Z (because that's how the pro's seem to do it.)
Also I would have made some sort of box enclosure for a Mendel style printer anyway, so I chose to make it all from the box.

I have gone for 2 motors on the Y axis.
Purely because I had the motor spare and it seemed easier to go that route than to arrange a mechanical linkage for one motor to drive 2 sides.

Maybe one motor driving one side would have been ok, as Zavashier says; there is very little chance of the Y axis skewing or 'crabbing'
It just didn't look quite right and the extra outlay was minimal.

I'm using the v-slot and wheels for XY and some 10mm ground bar + SC10UU's for the Z (I already had them)

If I were to start again, I think I'd make it all from v-slot, and use the mini wheels for some of it. It's nice stuff to use, really easy to set up.

Alan

Nice projet Alan, do you have a link or a topic here ?

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Collective intelligence emerges when a group of people work together effectively. Prusa i3 Folger (A lot of the parts are wrong, boring !)

Thank you Zavashier.

I've been 'lurking' around here a while but not posted anything. I will maybe add a thread in the extruded aluminum section.

You've set me thinking to lose that 2nd Y motor now. - It looks the part but I don't think it's doing a such a lot.
I would think that the Y carriage will move the same if pulled from one side as two. The stepper driver can't delivery any more power to two motors than the one, AFAIK,
Hmm.

Regards

A