Shell doesn't connect to infill?

[Nick__Mad 0]

Hello community! Long time no see.🙃

 

So, my UM2 Extended+ was doing great until recently I encountered a bit of a problem.

 

When I changed to my 0.4 ruby nozzle the printer stopped connecting the shell lines to the infill. (see pics with telegram logo)

This came completely out of the blue. The printer was making great prints up until that moment.

 

So I started troubleshooting. I thought that the nozzle was simply clogged and did several cold pulls. It was indeed clogged and I got it clean as a whistle. (see pink cold pull pic)

The problem persisted however.

So I thought that my feeder might have plastic debris in it (it did). I took apart the feeder box, cleaned the insides, greased the gears and slapped it back together. Didn't help much.

 

After that I went looking through the forums to fin a solution. Saw some post saying that changing the TFM coupler solved the problem for someone.

I coincidentally had a spare new one and mine was a tad worn out. (See pic)

While I was changing it I cleaned and re-oiled the print head carriage. That helped significantly but didn't make the problem go away completely.

 

Then I decided to try and switch to a regular 0.8 brass nozzle assuming that my ruby nozzle went bad (even though it should not be possible.)

 

I started an led box print. The result was quite good but the "ears" I have made for the bolts still have the "disconnect" issue.

 

And at this point I don't have much of an idea what else I can do to fix this.

 

The only thing that helped me hide this "disconnect" is by enabling the "ironing" feature in Cura. The nozzle ironed out the top layers and hid the seam. But that's merely a cosmetic solution.

(see pic with telegram logo that has no "disconnect")

 

About the settings in Cura. I use defaults and only use roof\floor supports from time to time. I use Cura 4.8.0.

 

Additionally, I have checked the tension on the short belts, and they are tight.

 

I will include the stl files for the prints mentioned in this post

 

Can you guys tell me how to fix this? 

 

(A link to images in full size here https://imgur.com/a/gwwDGJD)

 

Bike_Led_Prefina_3l.stl Telegram-pins.stl

Edited November 22, 2020 by Nick__Mad

[Nick__Mad 0]

My bad. Turns out my nozzles were worn out into oblivion. Got myself new ones and that fixed it.