Same old question .

I would like your option about banggood 8mm 8 pitch lead screws. Up in till now I have been using #10 threaded rods with reasonable results( I have been happy with them beside the PITA Z wobble artifacts) however in my quest to better prints, I have bought 8 mm 8 pitch lead screws , Cheap Cheap ones. Now im finding to get the same 0.1 layer height I have to set my slicer at 0.08 and even then its not as good. So my question is, Would I do well in replacing my 1.8 nema 17 with 0.9 nema ? would it help with better layer heights?

Thanks, I do realize this question probably been asked more then once, nonetheless I appreciate your response.

You need to calibrate the printer before setting layer heights in the slicer. Did you change the mm/rev setting in the firmware when you changed lead screws?

Can you share the link to the banggood screw?

lol yes , Marlin is indeed set up for the lead screws the steps are set at 400.00, here is the link to them [www.banggood.com]. they do work and I don't have anymore Z wobbles with them but I fear the resolution is not great because of the 8mm Pitch , that why I am wondering if I switch my 1.8 nema to 0.9 if that would help.

Edited 1 time(s). Last edit at 09/22/2016 12:07AM by Tibuck.

How is 400 steps/mm not very good? That's 0.0025 mm per microstep...

I can't see any benefit from going to smaller resolution.


Why do you say that you need to go to 0.08mm on your slicer? If you print a cube that is 20mm high (using 0.1mm or 0.2mm layers in your slicer), how high does it end up?

Edited 1 time(s). Last edit at 09/22/2016 03:29AM by nebbian.

The size ends up being 20mm regardless, the issue is not size dimensions, it print quality. I have been printing with the #10 rods for well over a year, and what I mean by all of this is to get the same detail I was getting at 0.1 I have to now set my slicer at 0.08 and according to Prusa calculator you would be right 0.1 would be the correct layer height settings but it looks like S@@T

moral; if you are going to upgrade to lead screws, dont buy the cheapest things you can find.

---

If you need some help, or don't understand what I just said, feel free to send me a PM anytime

Printer: Prusa i3, 2 E3D v6 Hotends, Arduino + RAMPS 1.4 with a Bypassed 5V Regulator, 400w Insignia ATX PSU, Custom Designed Bowden Extruders

In what way is the .08 setting "not as good" as before? Do you get better or worse results with .12 layers? One thing to be wary of when switching to 8mm lead is the increase in torque needed. It's quite easy to exceed the motor's capabilities and start missing steps. Dialling back the Z acceleration and feedrates may help, unless you have a heavy X axis, in which case a bigger motor might be needed. My Z axis is belt drive to the lead screws, and I recently swapped out the 20T pulleys for 40T to get a 2x mechanical advantage and more tooth engagement. That fixed both missed steps and jumping belt problems that I was suffering from, both of which were giving me print quality issues.

@DaGameFace I totally agree, I did pick up the cheapest I found only because around here , good lead screws are hard to get a hold of, and the cheapest I seen went for 45$ CAD for 1X 300 length and there is no way in hell im paying those prices for them loll And before I even think of paying that kind of money for those lead screws I wanted to make sure the upgrade would be worth it,

@JamesK its not .08 or 0.12 Layer height its 8mm lead screw pitch per mm, I was using #10 threaded rods that was 1.0583 Per mm, and those had better print resolutions then the lead screws Meaning the layer lines OR build lines, are more apparent with the lead screw then they were with the threaded rods. So my thought was if I switch to 0.9 degrees steppers it would mean twice the number of steps per mm and perhaps fixing the layer height build lines.

Not following you. The print resolution is the layer thickness, and you can set that smaller or bigger than the .1 layers I think you said you were using before. How far the motor turns to achieve the layer height is irrelevant. I use 8mm lead screws too, and I don't see any issues as a result other than the reduced number of choices for layer heights if you want to stick to the recommend full-step intervals.

Perhaps you could add some photos to show what the problem is?

Little update, I think I figured out why I think my prints are not as good with the lead screws as with the rods, For some reason one side of my z axis drops back down a half of a mm when rising , Example, If I raise the z 40mm, the right side holds it position but the left drops a tad, almost like it rotates back to stop on the motors closes step. Has anyone had this happen ? FYI Marlin is set to turn motors off when not in use, perhaps the dirty fix would be to keep them on ???

Never turning off the motors is the fix.

Quote
Tibuck
Little update, I think I figured out why I think my prints are not as good with the lead screws as with the rods, For some reason one side of my z axis drops back down a half of a mm when rising , Example, If I raise the z 40mm, the right side holds it position but the left drops a tad, almost like it rotates back to stop on the motors closes step. Has anyone had this happen ? FYI Marlin is set to turn motors off when not in use, perhaps the dirty fix would be to keep them on ???

I had this problem as my X axis is fairly heavy, especially on the side with the X axis motor. I would see a levering affect from the weight so the left side would rise, the right would fall on every layer. The easy solution is to use anti-backlash nuts. This can be made easily by using 2 brass nuts separated by a spring. The stronger the spring, the less backlash you get but the more stiction you add to the system, and the stronger the motor needs to be to overcome it. I used a delrin nut instead, as these are made to better tolerances but 2x brass nut should work well too.

that is very good advice and exactly what I planed on doing to solve , I am awaiting a few sets of those brass nuts, Im not sure what Delrin nuts are but I will goooooooogle and have a look, If it a better option im all for it .BTW my drooping is on the opposite side of the motor which is odd seeing how its the lightest of the two, Perhaps that motor is starting to crap out! ??