Black gunge on lead screws!

When I first got my X1C I lubricated the screws then after not much use I got the lubricate lead screws message as other have. I wiped off the grease, then reapplied, all very straight forward.

Next time I had the message I noticed there was some black contamination in the grease particularly evident on the two front lead screws. When I regreased it I made sure to clean all the existing grease off thoroughly to ensure I was starting with clean screws.

I have the black build up again and no idea where its coming from. If I was printing with mostly black filaments I might suspect that that could be the source but that’s not the case, maybe 200g since cleaning the screws, more than 1500g of other colours, plus the inside of the enclosure doesn’t seem to have any particulate fallout so my main concern is that somehow the screws or bearings are wearing prematurely and likely to fail.

Anyone else had this, identified the cause, solutions, or not worried?

i have this question as well. did you figure it out?

The ballscrews in the Z stage wear as they are used. That wear contaminates the grease and makes it look darker in color. It doesn’t take a lot of material to effect the color of the grease. Just like the oil in your car engine starts life with a “honey” color but turns black as it’s used, and it happens every time you change the oil, and it’s not an indication of anything wrong with the motor.

There’s nothing unusual or unexpected in this. You’re already doing what you’re supposed to do - when the printer complains that the Z-axis is gummed up and not moving correctly, clean and re-grease the screws. Ignore until then.

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The black sludge on your lead screws is simply a mixture of the factory-applied grease, accumulated dust, and microscopic metallic wear from the Z-axis as it oxidizes over time. It is completely normal for active 3D printers, but it requires cleaning to prevent print artifacts or motor strain. If you are a heavy user and print a lot, its best to clean and re-grease the lead screws every 1 to 3 months. Good luck!