Uneven extrusion along X Axis

[jimmy2times 0]

Hi there

 

I am using an Ender 3 with direct drive and heated glass buildplate.

I print with PLA+

 

After I switched to a direct drive I noticed that the extrusion along X axis is uneven. 

It is most noticeable in the 1st layer.

 

My only work around it is squishing the 1st layer to fill in the gaps in the X axis. But that of course causes problems in the first 10 layers or so. 

 

I replaced the 3 nylon wheels the direct drive is using but it didn't help at all.

I verified the filament driving gear and it looks good too.

 

What could possible be causing that?

 

Thanks!

 

 

[GregValiant 1,489]

Looking at the areas of skin that show the problem, the X axis areas just outboard don't look so good either.

Hot end is tight?

Bed is heating evenly?

If you have a decent magnifying glass take a look at the individual extrusions.  I'm far away but the ones that are split apart look pretty round (not squished) while the ones that appear welded together seem to be flat like they should be.

 

What is the last thing you changed on the printer?  Check it over again.

[jimmy2times 0]

Hi Greg,

 

Thanks for your answer.

 

So the last thing I changed was the extruder.

I switched to direct drive.

I moved the extruder along X axis and realized that it wasn't moving evenly. It felt like it was falling into a notch every coulple inches.

I replaced the wheels and it is now moving smoothly. I reckon some wheel shape irregularity was causing the nozzle to move wobble vertically while the extruder was moving along the X axis.

I have also reduced the inner wall flow. The quality has has improved a lot. But the uneven extrusion along X axis is still there, but has improved a lot.

 

I will try and verify if the bed is heated evenly. 

 

Should I upgrade the x axis to a rail and get rid of the wheels?

[GregValiant 1,489]

"Wheels vs Rails" is mostly a personal preference thing BUT you have added a lot of weight to the print head.  Before making the investment and putting the time into it I'd want to find out if the rail would help carry that extra weight.   It's possible you could end up with "different" but not "better".

For a test print you could turn your Accel down.  Getting the weight moving and then stopping it is going to put extra stress on the belt (which I assume you have adjusted correctly).

Here is a little post processor that may help you calibrate.  It allows you to split the X/Y Accel and Jerk so each axis can have a different value.  Unzip and put the file into the "scripts" folder within your Cura Configuration folder (on Windows it's "C:\Users\USERNAME\AppData\Roaming\cura\5.4\scripts").  It will be available (after a Cura restart) when you add a post processor ("Extensions / Post Process / Modify Gcode" then "Add a Script").

 

 

 

 

LimitXYAccelJerk.zip

Edited August 9, 2023 by GregValiant