Lead Screw Wobble

Question

I've been having issues with a sin wave in my prints. I think it's being caused by the lead screw wobbeling and thus pushing an pulling on the gantry. I've tried tightening up the guides but if tighten it any farther it's too much and the gantry wont raise of lower.

Anyone else having this problem? Any ideas on how to fix it?

FirstSonOfTyr · Accepted Answer

I actually created a bracket for the top as well.

It's not the best due to not having very accurate measuring device (only a ruler). Now I have some calipers and will be recreating it with better measurements. The lead screw cap actually sit inside well and I've lubed it with CLP (gun lubricant). It hasn't taken the wobble out though.

I'm going to get the upgrade coupling recommended above. By jamming my finger between the various parts and the frame I can feel that the motor drive shaft doesn't wobble, the coupling doesn't wobble but the screw does. Thus I've determined that the screw is not centered on the drive shaft.

Makertech 3D · Answer

A number of things need to come together to eliminate lead screw wobble.

Start first by removing the lead screw and making sure that the guides are loose enough to allow sliding but tight enough so that there isn't any wobble on the gantry when you move it by hand. The guides on the gantry are the trickiest to set up correctly, you want the gantry to be able to almost fall on it's own when the lead screw is not there.

Next is the positioning of the lead screw, the coupling and the motor shaft:

Make sure that inside the coupling the lead screw and motor shaft are touching.

Finally is the lead screw bracket and cap. The lead screw cap will need proper lubrication in order to be effective, the best in our opinion is dry bike chain lubricant (teflon kind), but cooking oil (olive/vegetable) works well too.

Then the lead screw bracket itself needs to be placed on top of the lubed cap, make sure that when you're fixing it that you've not pressed it down so much that it's pushed the lead screw to one side.

All three of these areas, the guides, the coupling and bracket need to be setup correctly for the best results.

Checking: Before printing lower the z-axis manually and then use pronter face to raise it up. Whilst looking at the gantry from the front of the printer, check to see if there's any side to side wobbling at the end nearest the LCD display.

Finally, I think it's worth mentioning that metal couplings are also available if anyone is still struggling with z-wobble and is wondering if any component itself could be upgraded. If you are considering this upgrade then we recommend the type that clamps onto the shaft, the correct size is 5x8.