First layer fails in one direction only.

Filament
1

Hi All

With my Taz5 & PLA I am doing a 1 player test print. When the first layer is being printed from left to right it works great, but when it is right to left it drags. You can see from the photo one half is fine (printed first) and the second half printed from right to left is messed up It happens in different parts of the build plate and everything seems level.

The problem is not limited to the first layer it seems to continue. I am printing at 185C with the bed at 55C and my nozzle has a very small leak but that does not seem related.

Not sure what to try next. I’m thinking it is laying down too much plastic and I should try and resolve that or turn the heat up/down a little.

Ideas?

Thanks
Brad

IMG_20150308_133601.jpg
IMG_20150308_133601.jpg1000×953 251 KB

image (8).jpg
image (8).jpg1000×563 173 KB

2

Ok, that’s an odd one Brad! Good photos and description by the way.

If what you say is true:

printing from left to right lays down a nice layer
printing from right to left leaves a torn layer

Then, have done 2 things:

  1. polished the tip of the nozzle. It could be that there is a bur on one side that is snagging when going one direction
  2. tried rotating the part 90° to print along the other axis (btw was this aligned with X or Y axis?).

You could also try rotating the infill 45° to see what happens then.

It really looks like a nozzle/orifice issue more than over or under extruding.

3

Thanks (and thanks for your other posts as well they have been helpful).

I have Cura and have not made the move to slic3r yet so I don’t have all those infill options. Cura does the infills at 45 degrees to the build plate but sometimes front to back sometimes the back to front.

I went with the nozzle blockage idea but could not see anything and I could not make an improvement. I switched over to HIPS as that runs hotter and maybe it would dislologe the blockage. Alas it did not.

When I extruded PLA the first 3mm is not straight but after that it is straight and smooth. HIPS was weird. So weird I am getting the same as BaltimoreBully so I am going to jump over to his thread https://forum.lulzbot.com/t/taz-5-hotend-problem-please-help/1399/1

4

Not just blockade but actually polishing the outside tip with polish or toothpaste to make it shiny smooth.

This is a very odd phenomenon that I have not seen before so I am very curious to sort it out (the twisted purple HIPS in the other thread).

BTW, sometimes just rotating your part in Cura will coerce it to change the infill direction. It’s a round part though so it might not. But it would be good to figure out how to test this.

If I had a Hexagon hot end I could slice and send some gcode to test. But I have every other hot end on the market except the Hexagon!

5

Are you sure you bed is level? Looks like its having a hard time extruding the filament on the one side.

6

I thought of that but if you zoom in to the photo you’ll see the perimeter beads are actually laid down with a nice consistent thickness. So I ruled out leveling. Could be a hump in that area but the OP said that he’s printed in different parts of the bed with the same result so it is not bed-position dependent.

7

My first thought was bed leveling also… but it seems to propagate through the project as shown in the picture with the pyramid…

Alsmost seems as though the X-axis is binding… but that doesn’t make complete sense either. Maybe be worthwhile to lube the rods.

8

How are things changed when you increase your first layer height by half a turn on your first layer thickness? How clean is your hobbed bolt?

What’s your filament diameter average and how does that compare to your value in Cura?

9

The nozzle is clean (I bought a new one)

The model is too thin to increase the height so I am going to change the width. I’m thinking you may be right, too much overlap.

10

In the end I got a new hotend to fix my problem. This is what I learnt along the way.

Read mhackney’s guides. https://forum.lulzbot.com/memberlist.php?mode=viewprofile&u=1439
Change only one thing at a time
Make some standard test prints and keep them.
Changing too many things at once is a lottery.

11

I made that mistake before… I think lottery gives to much false hope. More like Russian Roulette.