Custom 3D printer lead screws

Hello Fellow RepRappers,

I am in the process of designing and building my own custom 3D printer, and I have run into a bit of a road block when it comes to finding a Z-axis leadscrew. I have spent several days researching and searching for a good leadscrew, and I have a pretty good idea of what I want, but every time I find something close, I notice the specs are missing or ambiguous or something is not quite right. What I really need is people with more experience than me with 3D printing leadscrews to point me in a good direction of where to go. I am building a Cartesian bot, so I only need a single leadscrew. Any links to lead screws you have used or websites that sell good leadscrews and are easy to purchase from without having to make a custom order or call into would be awesome!

What I Think I want:

- A leadscrew, not a threaded rod!
- Stainless Steel, although I'm not completely sure which alloy is the best.

What I'm Not Sure About, But Need to Know Before Continuing:

-The thickness or "M" class of the threaded Rod. Is M8 fine? I plan on having a large build area, with a metal build plate, and there will be two 12mm smooth rods to take the weight of the whole platform, but will the rod need to be equally as thick? Will it experience a large load?
-I'm not sure where to go on the pitch of the rod. I'm pretty sure I want a rod with a pitch that is no more than 3mm, so with a Nema 17 and 1/8 microstepping I could get tolerances of .001 in. or .02 mm, or 200 microns. Is that reasonable? I see a lot of leadscrews on the market with an 8mm pitch, and that seems really large, is that too big? Should I go smaller than 3mm?
-Are the integrated Nema 17 Steppers/leadscrews any good? Is it worth it? I see, such as here, a stepper/leadscrew combo but it has both "threaded rod" and "leadscrew" in the name which are completely separate things. What's up with that?

It's a lot of questions, but this problem has been really bottlenecking me over the past couple days, and I haven't been able to get past it. Once again, any links and help would be, and is, greatly appreciated.

Thank You Very Much!

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DatRoboticsGuy
Hello Fellow RepRappers,

I am in the process of designing and building my own custom 3D printer, and I have run into a bit of a road block when it comes to finding a Z-axis leadscrew. I have spent several days researching and searching for a good leadscrew, and I have a pretty good idea of what I want, but every time I find something close, I notice the specs are missing or ambiguous or something is not quite right. What I really need is people with more experience than me with 3D printing leadscrews to point me in a good direction of where to go. I am building a Cartesian bot, so I only need a single leadscrew. Any links to lead screws you have used or websites that sell good leadscrews and are easy to purchase from without having to make a custom order or call into would be awesome!

What I Think I want:

- A leadscrew, not a threaded rod!
- Stainless Steel, although I'm not completely sure which alloy is the best.

What I'm Not Sure About, But Need to Know Before Continuing:


-The thickness or "M" class of the threaded Rod. Is M8 fine? I plan on having a large build area, with a metal build plate, and there will be two 12mm smooth rods to take the weight of the whole platform, but will the rod need to be equally as thick? Will it experience a large load?
-I'm not sure where to go on the pitch of the rod. I'm pretty sure I want a rod with a pitch that is no more than 3mm, so with a Nema 17 and 1/8 microstepping I could get tolerances of .001 in. or .02 mm, or 200 microns. Is that reasonable? I see a lot of leadscrews on the market with an 8mm pitch, and that seems really large, is that too big? Should I go smaller than 3mm?
-Are the integrated Nema 17 Steppers/leadscrews any good? Is it worth it? I see, such as here, a stepper/leadscrew combo but it has both "threaded rod" and "leadscrew" in the name which are completely separate things. What's up with that?

It's a lot of questions, but this problem has been really bottlenecking me over the past couple days, and I haven't been able to get past it. Once again, any links and help would be, and is, greatly appreciated.

Thank You Very Much!

You could look at the Tinkerine and Unimaker printers for ideas on lead screws. I haven't checked but they might spec the pitch on the ones they use.

Edited 1 time(s). Last edit at 05/07/2015 09:56PM by Vanbot.

Yeah, I've checked on Ultimaker before and was unable to find anything. I just checked on Tinkerine and it was the same story. I suppose I could contact them and ask, but there is no guarantees with that, and it'll probably take a while and I can gather more (probably better informed) opinions from here!

Kudos for recognizing the difference between lead screws and threaded rods! We need more of that around here...
Are you planning to lift a cantilevered print bed with a single screw? How big/massive is the bed?

I'm not entirely sure what you mean by cantilevered bed, but if you mean a bed where the support rods are in the back, and the bed hangs out over unsupported the rest of the way then yes. I have it designed right now so that two smooth 12mm rods are on the outside with linear bearings holding most of the weight while in the center the lead screw runs. The bed is currently designed to be 12x12 inches, or about 300 x300 mm, and that is not just an arbitrary number that I chose at random, that is the size requirement I need for a series of objects I really would like to print, so that number is pretty concrete. The material is going to be aluminum, probably 6061.

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DatRoboticsGuy
Yeah, I've checked on Ultimaker before and was unable to find anything. I just checked on Tinkerine and it was the same story. I suppose I could contact them and ask, but there is no guarantees with that, and it'll probably take a while and I can gather more (probably better informed) opinions from here!

I believe there's a BOM out there for people to build their own Ultimakers. Here in fact: [github.com]

I was not aware of this. Thank you!

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DatRoboticsGuy
I was not aware of this. Thank you!

Hope it helps.

The original Ultimaker used a trapezoidal thread TR 8×8(P2) RH DIN 103 Tol. 7e made from C15 steel according to the drawings and bill of materials they have published. When I checked the bill of materials for the Ultimaker 2 the same part number (B1159) is called out for the motor / lead screw.

Hmm Ok. Thanks For the tip. Would anyone by any chance recommend the Stepper/lead screw combos?

I've used stepper/lead-screw combination and was pretty happy. They are slightly more rigid/concentric since you can skip the coupler.

I'm pretty sure that whether you buy the combined stepper/screw or separate pieces they are all coming from the same factory. I think they are unpopular since they are awkward to ship and more expensive than separate components.

Edited 1 time(s). Last edit at 05/07/2015 11:09PM by 691175002.

That's good to know! I wouldn't have to make or buy a coupler.

When 8mm pitch is too much, why don´t you use gears between leadscrew and stepper? There are gears with no slack, so you wouldn´t lower the accuracy.

Imagine,one day the stepper/leadscrew combo failes .
Replacing a separate stepper is much easier done..
Olaf

It might also help to know where in the world you are here in Europe we have Dold who do 1 mtr lengths of TR10x2 (Which would be fine for what you need and 2 mm pitch) and they are around the 7 euro mark which I guess is about $10 us see

Trapezoidal leadscrew's unfortunately the site is in german but google translate is your friend here and the owner speaks english.

hth

Doug

These are a bit of overkill, but I like how smooth they work. SFU1204 LINK to Amazon they have 4mm pitch seemed a bit high, but using a regular Nema 17 stepper and had no issues. I replaced the 10mm one that came with my first kit printer and new one gave me much smoother movement. Old one was black steel; I have not idea where they sourced it but it sucked.

robotdigg does stepper motors with lead screws at different lengths too for couple of different printers

Edited 1 time(s). Last edit at 05/08/2015 12:21PM by chris33.

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Check my rubbish blog for my prusa i3

up and running
[3dimetech.blogspot.co.uk]

Ive been looking at lead screws recently.
Is the fine 1.5mm pitch desireable over the 2mm pitch screws?

After using 8mm x 1.25mm stainless threaded rod which has turned out to be pretty good with very regular cut threads.
Im wondering how good in comparison 8mm x2mm pitch lead screw would be.

1.5mm doesnt seem as easy to get hold of but loads of 8mm x 2mm pitch.

Gordon

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Gordon
Currently have a tweaked mendel prusa i2
About to build a P3Steel.
[scratchpad.thisandthose.org]

Printer for hire.
[www.3dhubs.com]

Member of South London Makerspace:
[southlondonmakerspace.org]

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gordonendersby
Ive been looking at lead screws recently.
Is the fine 1.5mm pitch desireable over the 2mm pitch screws?

After using 8mm x 1.25mm stainless threaded rod which has turned out to be pretty good with very regular cut threads.
Im wondering how good in comparison 8mm x2mm pitch lead screw would be.

1.5mm doesnt seem as easy to get hold of but loads of 8mm x 2mm pitch.

Gordon

We have a Tinkerine at our hackspace which uses a lead screw to raise the z axis bed. That lead screw looks to be a much steeper pitch than the hardware store variety threaded rod and works very well. Just a matter of calibration I suppose.

Does it matter whether I get a left hand or right hand leadscrew? Which is easiest to implement with most firmware versions?

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DatRoboticsGuy
Does it matter whether I get a left hand or right hand leadscrew? Which is easiest to implement with most firmware versions?

It makes no difference - it is easy to reverse the direction in some (probably most) firmwares, or you can just plug the motor connector into the electronics the opposite way round to reverse the direction.

Edited 1 time(s). Last edit at 05/09/2015 07:23PM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Quote
dc42

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DatRoboticsGuy
Does it matter whether I get a left hand or right hand leadscrew? Which is easiest to implement with most firmware versions?

It makes no difference - it is easy to reverse the direction in some (probably most) firmwares, or you can just plug the motor connector into the electronics the opposite way round to reverse the direction.

Alright Thanks!

Quote
gordonendersby
Ive been looking at lead screws recently.
Is the fine 1.5mm pitch desireable over the 2mm pitch screws?

After using 8mm x 1.25mm stainless threaded rod which has turned out to be pretty good with very regular cut threads.
Im wondering how good in comparison 8mm x2mm pitch lead screw would be.

1.5mm doesnt seem as easy to get hold of but loads of 8mm x 2mm pitch.

Gordon

Calculate the steps per layer:
200 steps/rev x 16 usteps/step (both typical) -> 3200 usteps /rev.
2mm pitch means 2mm/rev of the screw. 3200 ustep/rev x 1 rev/2mm= 1600 usteps/mm
0.1 mm layer -> 160 usteps. More than enough.

If it were 10-20 usteps per 0.1 mm I think it would be OK.

Lead screws, unlike hardware store threaded rod, are straight along the axis and round. You can put bearings at both ends like a proper linear positioner.

My thinnest layer height that i can see a physical difference in quality with the 8mm x1.25mm threaded rod is 0.06mm.
So the 160 microsteps at 1/16 sounds fine.
Ive just switched over to drv8825 1/32 drivers so it will double that anyway.

Thanks ill go for the 8mm x 2mm pitch lead screw.
The extra stiffness and accuracy over the length sounds attractive as well as ive been stiffening everything else up.
The stainless threaded rod ive been using does bend easily. You have to be very careful with it.

Gordon

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Gordon
Currently have a tweaked mendel prusa i2
About to build a P3Steel.
[scratchpad.thisandthose.org]

Printer for hire.
[www.3dhubs.com]

Member of South London Makerspace:
[southlondonmakerspace.org]

Out of curiosity have you found X-idler/pulley parts that work with the leadscrew(8mm)? I've yet to find anything that matches the P3 frame. The best I've found are these parts to help stabilize the top:

[www.thingiverse.com]

I'm using an m5 leadscrew which runs through a regular m5 nut that you can buy at any hardware store. If you're going to use an m8 leadscrew, I would recommend doing the same. Just buy an m8 nut from somewhere and attach it to your printer somehow. If you're talking about the piece that connects the x axis of the z-axis then I don't really know. I designed and printed my own piece to work with my printer

Edited 1 time(s). Last edit at 02/23/2016 10:38AM by DatRoboticsGuy.

It's hard to find TR8 leadscrews with a single start. Most are 4-start which gives an effective pitch of 8mm instead of 2mm. I just bought some off ebay (http://www.ebay.com/itm/381551545536]) but without nuts. I'll have to fabricates some (I have a lathe) or keep searching. I plan to cut down the ends of the leadscrew to 5mm (did I mention I have a lathe) and use a rigid 5mm coupler. Alternatively, I may put a pillow block at the top and a flex coupler at the bottom. I think one end or the other should have some "give".