I'm losing my mind over this problem with the inner wall of my cookie cutter prints.

[revcanon 0]

Using this attached profile in Cura 4.11.0 with Ender 3 Pro with eSun PLA+ 1.75 mm filament.

It doesn't matter what I try to print, the result is the same.

The handle of my cookie cutter prints fine.

The exterior wall prints fine.

The opposite side from the picture is fine.

The other side of the z seam is fine.

 

I have changed the nozzle and bowden tube. I have tried multiple profiles, changed retraction settings, temperature, coasting settings, and speed and NOTHING changes the outcome.

 

No matter what I change or what profile I use, this issue continues to occur only on the interior wall of the cookie cutter and only on the 1.2 mm blade and only to the right of the z seam by about 20 mm.

 

If I randomize the z seam, then it this issue exists anywhere it placed the z seam in each layer.

 

Any thing I print comes out this way.

 

WHAT AM I DOING WRONG?

Ender 3 Pro Cookie Cutter 0.4mm.curaprofile

Cheer_Megaphone_4_In.3mf

Edited October 27, 2021 by revcanon

[GregValiant 1,249]

The print head is taking a while to build up pressure to print.  Turn off "Retract at Layer Change" and set combing to "None" and see how it goes.

 

If you load that part in Cura and use "File | Save Project" you can post the 3mf file here.  It will contain the part and your printer as well as your settings and is easier to debug.

 

Starting about this time of year the "cookie cutter" problems start coming in here.  Thin walled models have their own set of problems so being able to see the model is a good thing.

[geert_2 557]

Is this a Z-seam issue? It rather looks like underextrusion to me? Just a guess, I don't know your printer.

 

Generally, printing slow, in very thin layers, near the lower edge of the temp range (=to prevent overheating and decomposing of the filament, due to sitting in the nozzle for a long time), tends to give the best results, in my experience. Also, in addition to the above suggestions, set all speeds to the same value (inner and outer wall, infill), so that the flow through the nozzle is as constant as possible. Wild speed variations cause wild flow variations, and thus temperature variations, and a lagging in nozzle pressure (=overpressure at the end of a fast traject, and underpressure at the start of it).

 

[revcanon 0]

10 hours ago, GregValiant said:

The print head is taking a while to build up pressure to print.  Turn off "Retract at Layer Change" and set combing to "None" and see how it goes.

 

If you load that part in Cura and use "File | Save Project" you can post the 3mf file here.  It will contain the part and your printer as well as your settings and is easier to debug.

 

Starting about this time of year the "cookie cutter" problems start coming in here.  Thin walled models have their own set of problems so being able to see the model is a good thing.

 

Thanks for your input.

 

I have added the 3mf file to my original post. Just a note: all of my prints are doing this.

I just got home from work.  I will print examples with the settings you suggested and post the results.

[revcanon 0]

4 hours ago, geert_2 said:

Is this a Z-seam issue? It rather looks like underextrusion to me? Just a guess, I don't know your printer.

 

Generally, printing slow, in very thin layers, near the lower edge of the temp range (=to prevent overheating and decomposing of the filament, due to sitting in the nozzle for a long time), tends to give the best results, in my experience. Also, in addition to the above suggestions, set all speeds to the same value (inner and outer wall, infill), so that the flow through the nozzle is as constant as possible. Wild speed variations cause wild flow variations, and thus temperature variations, and a lagging in nozzle pressure (=overpressure at the end of a fast traject, and underpressure at the start of it).

 

Thank you for your response.

 

I don't believe it is a Z seam issue. I too suspect under extrusion, but it confounds me why it only happens in this area of any print, regardless of where I place the Z seam.  I am going to try GregValiant's suggestions, but will adjust the speeds to be more uniform.

[revcanon 0]

I have attached the updated cura profile with the suggestions you made.

 

I stopped the print early as there was no improvement on the interior wall near the z seam. 

Ender 3 Pro Cookie Cutter 0.4mm_Take2.curaprofile

[GregValiant 1,249]

Here is the result from my Ender 3 Pro.  I would call it acceptable.  There was a very , very light under-extrusion when the nozzle moved away from the letters and continued the wall.  The Z seam is in the corner closest to the "M".

I'm attaching the 3mf file.

 

When was the last time you cleaned your hot end and trimmed the bowden tube?  A partial clog at the bottom of the bowden where it is supposed to seal against the nozzle can cause the same sort of problem as you are experiencing.  I finally gave up on the stock hot end and went with an all-metal.  REtractions over 6mm can cause problems as well.  The 3mf file you posted was an "export" and only contained the model.  You need to use Save Project to have a 3mf that contains your settings and your printer.

 

 

GVcookiecutter.3mf

[revcanon 0]

I actually replaced the nozzle and bowden tube this past weekend in an attempt to resolve this.

 

I just pulled the bowden tube again and made sure it was seated all the way down.

 

no change.

 

I understand your instructions for the 3mf file now.... 

 

attached as requested

CE3PRO_Cheer_Megaphone_4_In.3mf

Edited October 28, 2021 by revcanon

[revcanon 0]

i also tested it with another small model with no lettering on the side.... same outcome

[revcanon 0]

Pulled bowden tube again... trimmed it to try to make sure it was flush at the end of it.

Printed a small model.... still obviously under extruding there.

This weekend I believed this to be a heat creep issue, and I have tried to remedy that.

 

But as it is continuing to happen, I am starting to wonder if going with a new all metal hot end and new tubing may be one answer.

 

 

 

[revcanon 0]

I really appreciate the time and energy you have put into helping.

 

Admittedly, I do not know enough to fully diagnose this, but why would I only see this on the interior wall of the cutter blade if it were happening all over? How can the inside and outside of the handle and outside wall in the same area look fine if it's under extruding? If it isn't happening everywhere, then why would it only happen here?

 

I'm just so confused by what this is doing.

 

[GregValiant 1,249]

My printer started this pretty much all of a sudden.  I never did really figure it out.  I used the thermal grease, trimmed the bowden a million times, went with the fancy "real" pneumatic tubing connectors from McMaster Carr, altered my hot end cover and installed a 4015 fan, drilled holes in the back plate to let the air out, and printed a deflector to make sure the air was aimed at the heat exchanger.  Finally I went with a clone of the original hot end.  Same problem.  That did allow me to come up with a new saying though.."Never be surprised when you clone a piece of crap and come up with another piece of crap."

The all-metal hot end I went with is a clone of a good one.  It isn't perfect, but the maintenance is way less and it makes it through 24 hour prints just fine.

 

Using "Connect Infill Lines" limits the number of retractions in the infill.

When skins are narrow - Z-hops leave little tits sticking up so I generally turn off "Z-Hop on retraction".

You have "Retract before outer wall" ticked.  Turn that off.  Remember that you inside wall is also facing air and so it is an "outside" will to Cura.

At 0.4 line width - that model has a lot of starts and stops when filling in the "blade" portion.  At .35 line width I thought the motion was much smoother.  That 3mf file I attached earlier has my preferred settings.  If you slice it and print the resulting gcode you'll see what I mean.  There is way less motion with my settings and as @geert_2 noted - keeping the pressure consistent in the nozzle really helps.  The boatload of retractions required by your current settings can be an issue.

 

On the surface the filament management is such a simple arrangement - push, heat, extrude.  It's hard to believe it can be so hard to troubleshoot when it gets out of tune.

I do have some more wet PLA so I sliced the model with your settings and it's printing now.  We'll see.  This is how I learn this as well.

 

That STL file was created at a very low resolution.  At the big end of the megaphone the inner and outer radii ended up as a bunch of fairly long line segments that aren't "concentric".  That means that the distance between any point on the inner radius to an adjacent point on the outer radius is constantly changing.  I'm thinking that the Cura Arachne version might be a better choice for this model.

Edited October 28, 2021 by GregValiant

[GregValiant 1,249]

The print finished and it looks bad.  The inside wall is under-extruded where it starts at the Z seam as you described.  I think it can be attributed to all the retractions going on as it keeps switching between "Inner Wall" and "Skin".  Those are in the preview as the short green lines and short yellow lines that are inter-mingled between the outer walls.  There is also a longish travel move right before the inside wall starts, and likely "Retract before Outer Wall" is having an effect.

Here is the preview with your settings.  Each short yellow and green line ends with a retraction and Z-hop.  Not good.

 

This is with my settings.  Notice how the .35 line width has smoothed out the fill between the walls.  The "inner wall" now fits all the way around and there is no need for any of the yellow filling moves.  Also notice how the facet resolution of the STL file causes the varying thickness of the radiused wall.

 

This is sliced with Arachne.  Notice how the green lines vary in width indicating how Arachne handles the varying distance between the outer walls.  The motion is continuous with no retractions.

 

 

The print with my settings is in the front.  (The white mark is a slip with the exacto knife.)

 

 

 

[revcanon 0]

I finally found this article  describing the same issue I've been struggling with.

While trying to fix this, I have been playing with other's profiles trying to get this one thing fixed and I think other's profiles are causing some additional issues as you described.

 

I'm going to take some time to get my settings back to what was working great except for the under extrusion and try to dial in the Retraction Extra Prime Amount setting.

 

Meanwhile, I'm going to take some lessons from you on inspecting the preview after slicing.  I think I've been taking it for granted that if I don't get an error, then everything is fine.

 

[revcanon 0]

Switched to .35 line width and I believe I see much improvement in the preview.

 

Testing on smaller prints, looks like I have the retraction extra prime amount good too as the z seam is looking better.

CE3PRO_Cheer_Megaphone_4_In.3mf

About to try this one.

 

Edited October 29, 2021 by revcanon

[revcanon 0]

I do believe I have some more small things to dial in, but this particular issue does seem to have come down to Retraction Extra Prime amount.

[GregValiant 1,249]

Progress.  Sometimes it's baby steps but it always feels good when you are moving forward (as opposed to spinning your wheels or moving backward).

I have exactly one settings profile for PLA, one for PETG, and one for TPU.  I found that trying to keep different profiles for this and that just got confusing.  I keep all settings visible and go through every one for every model.  Then, after carefully making sure that all are right I start a print and immediately notice that I forgot to move the Z seam.  Oh well.

 

The extra prime is in mm³ so at .35 line width by .2 layer height you are at about 35mm of extrusion per 1mm³ of filament.  If your under-extrusion is about 12mm long then that would be .33 extra prime amount.

[revcanon 0]

I would like to thank you for all the info you provided in this thread.  Although you helped me solve the under extrusion after travel issue, one of the biggest things I took away from this thread is learning how to use the Preview in Cura.

I'm sure it's not perfect every time for every situation, but now I can look at the preview and look at a print I'm not happy with and find what's happening.  I'm now able to make small adjustments to some of the settings, reslice, and preview to look for differences in areas I'm having issues with.  It saves some filament if I can look at a preview and see immediately that it isn't going to behave the way I want it to rather than just printing and hoping after every setting change.  I've learned a lot this week, and you've given me some tools to learn and explore more.  Thanks!

[GregValiant 1,249]

You are welcome.  There was one person last year who posted a cookie cutter that the cutting edge was "sharpened" by adding a severe chamfer to it.  The poster was very disappointed when they found out that their printer couldn't do razor edges.  Everything has to be kept in the realm of possibility.  Determining exactly where the possible turns into the impossible is a key to all this 3D printing stuff.