Two stepper z-axis

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AudaciousTuddle
Ah. Now I see. I haven't thought about avoiding microstepping in layer heights, but I'm going to start doing that. Right now I have a 1.25mm lead so staying in multiples of .00625. Or .004mm once I get my leadscrews installed with the .8mm lead.

I fail to see the usefulness of such small pitch lead screw when dealing with molten plastic where 0.1 mm is high accuracy ! With a 0.8mm lead, 0.004 mm per step, it is CNC realm.
A 0.8 mm pitch is not a TR standard. Do you use a M5 threaded rod ?

I found a T5 x .8mm leadscrew. It's in the mail now. Currently I am using m5x1.25 threaded rods but they are pretty bent, which is why I am going to the leadscrews.

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WZ9V
Do people find they have problems with the two z-motors going out of sync and causing leveling issues?

I am having exactly this problem when attempting to move the Z-axis with the on-board controls. What I'm doing is LCD screen----settings----move axis----move z, then turning the knob. Whats happening is it's moving unevenly so one side droops, and the other raises, then the other side will move and catch up slightly. It'll then move evenly for a couple mm, then go out of sync again. How do I fix this, or is this just because I'm trying to manually move it? I took the green plastic sleeves off the bottom of the threaded rod and replaced them with flexible couplers because I thought that might have been the issue, but it has solved exactly squat. If this has already had a fix posted, please feel free to point me in the right direction.

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AudaciousTuddle
I found a T5 x .8mm leadscrew. It's in the mail now. Currently I am using m5x1.25 threaded rods but they are pretty bent, which is why I am going to the leadscrews.

Where'd you find the leadscrew?

Ishimonji - They aren't usually that bad. The issue we've been discussing is that when the motors come to rest and are shut off one motor can stop on one step if they were both at half step when the power went off and the other goes the other way so they end up one step apart ie 0.04mm higher at one end (with an 8mm lead).

What you're describing sounds like a loose coupler or bad motor or some bad binding in the smooth rod bearings. It might be too little motor current or too much.

Hmm...makes me wonder then. Sorry for jumping in. I've just been scouring boards and coming up empty so I thought this might be a light.

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Everything comes apart with a sledgehammer.

No that's fine very happy to help if I can. Does the axis move normally during printing? What about when you command a move from the computer?

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AudaciousTuddle
I found a T5 x .8mm leadscrew. It's in the mail now. Currently I am using m5x1.25 threaded rods but they are pretty bent, which is why I am going to the leadscrews.

5mm diam is too small. 8mm is the minimum usable. Standard M5 threaded rod pitch is 0.8mm, never heard of 1.25mm wich would be too coarse.

Where did you get TR5 with a 0.8 mm pitch ?. 1mm is the standard.

"Bent" is a normal feature in these diam - length

Edited 1 time(s). Last edit at 01/22/2016 05:19AM by MKSA.

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MKSA
Where did you get TR5 with a 0.8 mm pitch ?. 1mm is the standard.

I found these ones at [www.ebay.com].

I also totally screwed up some numbers. The ones I'm using now are M6x1.00. I got mixed up with another project that used M8x1.25. And if you do some wikipeading M5x0.8 or 0.5 is standard. Hopefully this guy isn't marketing threaded rods as acme screws, but the picture looks like it has the trapezoidal threads at least.

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AudaciousTuddle

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MKSA
Where did you get TR5 with a 0.8 mm pitch ?. 1mm is the standard.

I found these ones at [www.ebay.com].

I also totally screwed up some numbers. The ones I'm using now are M6x1.00. I got mixed up with another project that used M8x1.25. And if you do some wikipeading M5x0.8 or 0.5 is standard. Hopefully this guy isn't marketing threaded rods as acme screws, but the picture looks like it has the trapezoidal threads at least.

I am pretty sure these are just standard M5 threaded rods, not trapezoidal. The nuts are not fit for the purpose either, they are just common standard nuts.