YJB

These 6 parts, shown on the attached image, were all on the same print with the Y-axis parallel to the horizontal line defect. When I took the lead screw out I did not notice any bad spots as I moved the bed up and down it was all pretty smooth. Which make intermittent under extrusion more likely I guess. It looks like this horizontal defect is on the same layers more or less.

I took out the whole screw and cleaned it using WD40 and a toothbrush and unfortunately these horizontal lines won't go away. Not sure what to do now, any suggestions?

Always a good option ? I've worked out my ringing vs acceleration calculation as follows: -Distance between lines 1.1mm roughly -Print speed at the time 45mm/s -Frequency: 45/1.1= 35Hz (rounded up) -Acceleration 35*45=1575 mm/s2 I dialled this into Cura with my 3D Solex 0.8mm nozzle and I will report back with the results in a few hours. The dirty lead screw seams to be the cause of the horizontal lines. I tried cleaning it using some kitchen cloth and a screw driver while moving the bed up and down but it is still dirty i think. Are there any more thorough ways of cleaning it? I'm planning to stop using the Magnalube PTFE grease as it hold onto the dirt very quickly and replace it with MG Chemicals Lithium Grease. Do you guys have any advice for or against this change? Thank you very much for your support.

That's the one shown on the second attachment in comparison to 0.4mm nozzle from Prusa

I accept that - I just thought that the difference would be less significant between 0.6 and 0.4, but perhaps that's due my limited experience.

Unfortunately I can't. It's a confidential customer part. But the geometry is basically a rectangular cross section, built vertically with holes along the length. Orientation is clearer from the layer lines on my images.

I normally use Magnalube PTFE grease that you get with a new UM3 to lubricate the Z screw but it gets dirty very easily. When I give it a good clean, can i replace it with lithium grease instead, even though there maybe still remnants of the PTFE grease in the bearings and areas I can't reach?

I can't thank you enough for your prompt response. I'm trying to implement all your suggestions now and I'll report back with updates. Regarding the Prusa comparison, it is exactly the same Filamentive black PLA. The only difference is the diameter, being 1.75mm for the Prusa. But you are quite right in saying it's matt black on the prusa, but that's the printer's outcome. I'm not sure why it comes out Matt on the MK3 compared to the UM3. It maybe due to print temperature as it's 215C on the Prusa but 195C on the UM3. I also have S3D, so I would be extremely grateful if anyone here has 3DSolex 0.8/0.6 profiles that they can share. Once again, thank you so much for your support and I will report back with results later this evening.

Hi All, I'm having great difficulty utilising my UM3 to get good quality parts using the standard profiles / printcores. I'm using Filamentive PLA filament and after limited success using the AA0.8mm printcore together with the default Cura PLA parameters, I invested in 3D Solex print cores to see if I can get better results but unfortunately I did not. I'm sure it's due to my lack of experience and nothing to do with the hardware. Therefore I'm here trying to bring my issue to your experienced eyes and hopefully your advice will make my UM3 usable. I tried 2 nozzle sizes with 3D solex, 0.8mm and 0.6mm and the results are shown on the attached images. I compared the 0.6mm results to the same exact part printed on a Prusa MK3 (using a 0.4mm nozzle thoguh) and I could not even come close to that level of quality with my current ultimaker profile settings. I took my UM3 to the UK service provider, thinking maybe i have mechanical issues and they admired how well looked after my machine was and confirmed there were no issues with it at all. If you can guide me through a trouble shooting process I would be very greatful. I know the UM3 is a very capable machine and it's a real shame to not be able to use it. Many thanks for your advice in advance.