Lead screw upgrade

[printbus]

Thoughts on this lead screw

I'm going to leave this to anyone who's already done any form of a lead screw replacement. I think it was TechMasterJoe that said he had bought some rod to use. Where's he at with his mod?

I think it was either Prusa himself or Triffed Hunter that argues that on a threaded rod Z you ideally have a layer height that is an even number of full steps (not a microstep). I didn't bring up the Prusa calculator, but it seems if you follow that rule you'd end up with some odd layer heights.

[MiniMadRyan]

I'm going to leave this to anyone who's already done any form of a lead screw replacement. I think it was TechMasterJoe that said he had bought some rod to use. Where's he at with his mod?

I think it was either Prusa himself or Triffed Hunter that argues that on a threaded rod Z you ideally have a layer height that is an even number of full steps (not a microstep). I didn't bring up the Prusa calculator, but it seems if you follow that rule you'd end up with some odd layer heights.

This was of great discussion over on the printrbottalk forums, as the Printrbot simple used an acme rod. The layer heights suggested were weird, 0.28, 0.323 and so forth depending on what you wanted.

[printbus]

This was of great discussion over on the printrbottalk forums, as the Printrbot simple used an acme rod. The layer heights suggested were weird, 0.28, 0.323 and so forth depending on what you wanted.

Yeah - I've previously joked about how when I compared the effect of metric and Imperial rods in the Prusa layer height calculator, I thought about sending Colin a thank you note for using metric rods in his printers.

[MiniMadRyan]

Yeah - I've previously joked about how when I compared the effect of metric and Imperial rods in the Prusa layer height calculator, I thought about sending Colin a thank you note for using metric rods in his printers.

I agree. I remember the weird layer heights on my printrbot; in order to minimize the 'z-ribbing' effect on prints, caused the prints to be i believe 2% taller than they should have. Aside from some minimal wear on the metric rods on the MakerFarm, I've been more than happy with their performance.

[printbus]

For what its worth I did this mod http://www.thingiverse.com/thing:449341 and have had much better z axis movements and resolution. I originally got two 12" acme threaded rods and that greatly reduced the z height, I have since purchased a 36" piece and cut it down to the same length as the stock threaded rods.

I know this is not a precision lead screw but it works really well for me.

When I was looking for solutions earlier, I had ran across that. It looked like a promising option, except for the possible issue with Imperial vs metric threads. Can you elaborate on what you mean by "much better z axis movements and resolution"? How do you have DEFAULT_AXIS_STEPS_PER_UNIT and DEFAULT_MAX_FEEDRATE set up for the Z axis? Have you had any issues with the NEMA17 motors being able to drive the Z axis?

[brochapman]

When I was looking for solutions earlier, I had ran across that. It looked like a promising option, except for the possible issue with Imperial vs metric threads. Can you elaborate on what you mean by "much better z axis movements and resolution"? How do you have DEFAULT_AXIS_STEPS_PER_UNIT and DEFAULT_MAX_FEEDRATE set up for the Z axis? Have you had any issues with the NEMA17 motors being able to drive the Z axis?

I am at work now, so this is off the top of my head. DEFAULT_AXIS_STEPS_PER_UNIT is set to 2015.7 for Z, the person that designed the mod says it should be 2015.748. I dialed in 2015.7 through the front panel and have not looked back. I will have to look at the firmware tonight to tell you the MAX Feedrate. The Nema 17 motors have had no issues with driving the acme screws. I had my concerns and kept monitoring them for over heating and they actually stay cooler now than with the threaded rods. Here are a couple pics of my install, http://www.thingiverse.com/make:100198 (please ignore the wiring mess, its on my todo list to clean up )

What I mean by better resolution is that before I would randomly have tiny gaps or bad layer adhesion. I tried everything people recommended but it was random, the first 20 layers would be fine then a bad layer, then 10 more and another bad layer. and it was completely random, next print it may be 10 layers before a bad one. I was thinking it was a bad spot in the threaded rods so I replaced them with no change. my original threaded rods had a slight bow to them and that always bugged me. Now after this upgrade all those issues went away.

Like everything it seems in 3d printing this is my experience and your mileage may vary. I never liked the threaded rods with the tubing connector.

I will try and get some pictures this evening to show how it prints now, I think all the old prints are broken apart in my scrap pile.

[usarmyaircav]

I will keep this in mind as an upgrade, as I seem to have some inconsistent layer gaps, and my z rods are not straight and it bugs me, so this might be a nice update, and potential fix.

[adamfilip]

What do you guys think of this product i found on amazon
http://www.amazon.com/Miniature-Qual...s=M6+Leadscrew

[printbus]

What do you guys this of this product i found on amazon
http://www.amazon.com/Miniature-Qual...s=M6+Leadscrew

Interesting...

[adamfilip]

http://www.qtecstore.com/pages/screw...rive/page.html