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Benchy has extreme bulge?  

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Arnav Prasad
(@arnav-prasad)
Active Member
Benchy has extreme bulge?

Hey all, just got my Duet3 hooked up to my printer (In a former life it was a CR-10S, but now it has all sorts of upgrades including direct drive, AC bed, etc...)

I've been a Simplify3D user for a while, but then took a long break from printing. Getting back into it, everyone recommended PrusaSlicer to me, and I printed a benchy. As you'll see in the attached picture, there is an extreme artifact prominent in the bow of the boat. Googling leads me to believe this is a bulge, not a layer shift, but none of the posted solutions seem to solve my issue...

I used PrusaSlicer to make a 20mm calibration cube - came out beautifully, no artifacts, great tolerances. But the Benchy is still awful!

I tried the same Benchy file in Cura, for fun - it came out somewhat under extruded (I rushed and didn't tune anything) but the artifact was not there at all. So is something wrong in my PrusaSlicer settings?

Appreciate any help you can provide - first time posting here, so if you need any extra info, please advise.

 

3DBenchy.3mf

Posted : 27/07/2021 6:17 pm
cwbullet
(@cwbullet)
Illustrious Member
Other prints

Has this happened on other prints?

--------------------
Chuck H
3D Printer Review Blog...
Posted : 27/07/2021 6:21 pm
Arnav Prasad
(@arnav-prasad)
Active Member
Topic starter answered:
RE: Other Prints

The only other print that I ran so far was the XYZ 20mm calibration cube. No issues or bulge there whatsoever. This almost looks like not a bulge, but as if the printer is being told to repeat a layer or something - I'm really not sure what's happening.

But also if you'll notice in the picture -- The "bulge" looking thing then lines up with the higher parts of the bow of the ship... but it's not a layer shift, because it happens all the way around the part equally, even if I rotate the part when plating it...

This post was modified 2 months ago by Arnav Prasad
Posted : 27/07/2021 6:22 pm
bobstro
(@bobstro)
Illustrious Member
No one fix, a few things you can try

That's the infamous line that corresponds to the level of the deck inside Benchy. Search for the term "buldge" and you'll find a slew of related posts. Also, Prusa has a knowledgebase article on this specific issue. In short, you can tune it down, but there's no one set trick. A few quick things to try:

  • Slow down 50% and see if anything evens out. 
  • Make sure your extrusion multiplier is correct for your filament. Since you updated the controller, you might want to confirm all axis step calibrations.
  • Toggle thin wall detection.
  • You can twiddle the perimeter extrusion widths which will sometimes help.

Your print looks rougher overall than the examples we usually see, so there may be some other issues at play on your Creality printer. You've got your cooling fan set to auto cooling, but always on is generally recommended for PLA.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 27/07/2021 6:27 pm
Arnav Prasad
(@arnav-prasad)
Active Member
Topic starter answered:
"Buldge" Solutions

Thanks for the input! I actually did find articles about the so-called "buldge" earlier, but running down their list of fixes didn't seem to do a whole lot for me. I uploaded the original .3mf here, but I have attempted with the "detect thin walls" off, changing the number of perimeters, etc. I should try a slowdown by 50% and see if that fixes things - if it does, does that just mean my speeds for all parts are too fast?

I have checked the steps per mm for all my axes, and they are dialed in pretty well - so I don't think that is the issue. I definitely can try turning down the extrusion multiplier some more, need to calibrate that still. I'll turn the fan to always-on, too.

I had never seen this before - I guess I'm curious why I could be running into it so egregiously, when I've watched so many people do "live printer unboxing streams" on YouTube and seemingly print Benchy's out of the box?

Posted : 27/07/2021 6:34 pm
bobstro
(@bobstro)
Illustrious Member
Hard to say exactly
Posted by: @arnav-prasad

Thanks for the input! I actually did find articles about the so-called "buldge" earlier, but running down their list of fixes didn't seem to do a whole lot for me. I uploaded the original .3mf here, but I have attempted with the "detect thin walls" off, changing the number of perimeters, etc.

Looking at your print, I'd work with some 20mm cubes until the walls start to look more even and consistent. Those will print much more quickly. It could just be the picture, but it looks rough. Post some more if you can.

I should try a slowdown by 50% and see if that fixes things - if it does, does that just mean my speeds for all parts are too fast?

That's a quick and easy check for a bunch of issues, but yes: It can indicate your print speeds are too high. I did look through your 3MF and the speeds look fine (60mm/s & 50% perimeter speeds).

I have checked the steps per mm for all my axes, and they are dialed in pretty well - so I don't think that is the issue. I definitely can try turning down the extrusion multiplier some more, need to calibrate that still. I'll turn the fan to always-on, too.

The lower bow on your Benchy isn't deformed, so your heating is OK. If you are having issues with overhangs, more cooling helps. Dial back that extrusion multiplier and see if it helps. That line will flag over extrusion since the solid layers of the deck can push out on the hull.

I had never seen this before - I guess I'm curious why I could be running into it so egregiously, when I've watched so many people do "live printer unboxing streams" on YouTube and seemingly print Benchy's out of the box?

It looks like you're within the range of just needing to tune. Having swapped in a new controller can introduce a host of issues though. I'd print some smaller diagnostic prints that check one thing (e.g., bridging, overhangs, extruder) just to speed the process up.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 27/07/2021 6:42 pm
Arnav Prasad
(@arnav-prasad)
Active Member
Topic starter answered:
Calibration Cube Quality

That's encouraging! Glad to know it's likely a tuning thing. So far I love the Duet (over the Creality board from before...) and being able to tweak settings with GCode instead of flashing firmware is awesome.

Here are some pictures of the calibration cube I printed out -- I included one of the X face, where the walls look kinda rough, and a picture of the Z (top) face. It was hard to capture, but in the Z image, does that look over extruded? If so, I'll have to dial back my extrusion multiplier. It's hard to know how it "should" look, though, since my CR10 even from day 1 never produced fantastic prints. Any advice about the rough side walls?

Posted : 27/07/2021 7:43 pm
cwbullet
(@cwbullet)
Illustrious Member
RE: Prints

 

Posted by: @arnav-prasad

That's encouraging! Glad to know it's likely a tuning thing. So far I love the Duet (over the Creality board from before...) and being able to tweak settings with GCode instead of flashing firmware is awesome.

Here are some pictures of the calibration cube I printed out -- I included one of the X face, where the walls look kinda rough, and a picture of the Z (top) face. It was hard to capture, but in the Z image, does that look over extruded? If so, I'll have to dial back my extrusion multiplier. It's hard to know how it "should" look, though, since my CR10 even from day 1 never produced fantastic prints. Any advice about the rough side walls?

 

CR-10 can be a struggle.  I have one in my donated rebuild pile.  Although there is room for improvement.  The prints are not bad.  

 

Like Bob said, did you slow it down?  

--------------------
Chuck H
3D Printer Review Blog...
Posted : 28/07/2021 1:52 am
Swiss_Cheese
(@swiss_cheese)
Noble Member

Looks to me (from your picture) as if you may be printing with the wrong filament profile.

The Filament Whisperer...
Posted : 28/07/2021 9:08 pm
Arnav Prasad
(@arnav-prasad)
Active Member
Topic starter answered:
Profile

What makes you lean that way? I have a generic PLA profile set up, though as was pointed out earlier I definitely should switch the part fan to always-on.

Posted : 28/07/2021 9:31 pm
Swiss_Cheese
(@swiss_cheese)
Noble Member

I was thinking that, because as I look at the pictures of the prints they seem over extruded and as though to much heat was used. I'm not saying this is the case, but I have seen prints posted like this, and it turned out in some cases that the user was printing PLA using a PETG profile for example.

 

also I've seen the reverse of this were folks will accidentally load PLA when they intended to print PETG, it happens and it kind of looks like your images when it does.

 

Just a thought, it might have been worth mentioning.

 

Regards

 

Swiss_Cheese

The Filament Whisperer...
Posted : 28/07/2021 10:30 pm
Arnav Prasad
(@arnav-prasad)
Active Member
Topic starter answered:
Re: profile

Ah gotcha! Thanks. It's a good point. I am now tuning my extrusion multiplier, as you're right, I think it is too high. I will see how we do after that is dialed in. I have my PLA printing at ~205C -- maybe this is too high. Also, might be worth putting my filament through the food dehydrator, we've had a few humid weeks where I live.

I'm a little curious how you're replying without having to include those annoying "titles" that seem required on this forum... how are you doing that?

Posted : 28/07/2021 11:08 pm
Arnav Prasad
(@arnav-prasad)
Active Member
Topic starter answered:
Re: Speed

 

Posted by: @cwbullet

 

Posted by: @arnav-prasad

That's encouraging! Glad to know it's likely a tuning thing. So far I love the Duet (over the Creality board from before...) and being able to tweak settings with GCode instead of flashing firmware is awesome.

Here are some pictures of the calibration cube I printed out -- I included one of the X face, where the walls look kinda rough, and a picture of the Z (top) face. It was hard to capture, but in the Z image, does that look over extruded? If so, I'll have to dial back my extrusion multiplier. It's hard to know how it "should" look, though, since my CR10 even from day 1 never produced fantastic prints. Any advice about the rough side walls?

 

CR-10 can be a struggle.  I have one in my donated rebuild pile.  Although there is room for improvement.  The prints are not bad.  

 

Like Bob said, did you slow it down?  

Haven't slowed it down yet. I feel like my speeds *should* be ok, and I don't want to go too much slower, so I'm going to try and dial in everything else first before doing that. Primarily cooling, extrusion multiplier, maybe the external perimeter speeds, etc.

This setup is fairly temporary to be honest - I have my heart set on building a Voron 2.4. I'm a robotics guy through and through, and that's right up my alley. I wanted to print the parts myself, but now I'm looking at the Print it Forward program if this printer is going to be such a headache... Time will tell!

Posted : 28/07/2021 11:11 pm
Swiss_Cheese
(@swiss_cheese)
Noble Member

@arnav-prasad

 

you can reply without the (mostly annoying) but sometimes Fun "titles by simply hitting the space bar inside the title area once, if you edit your post it will try to add a RE: to the title and you can also just high-lite this and hit space bar once and then post.

 

as to your filament temperature it depends on the filament your using, however 205C seems like a safe average range temp for PLA.

 

Good Luck,

 

I hope this gets you closer to the clean print your looking for.

 

Swiss_Cheese

The Filament Whisperer...
Posted : 28/07/2021 11:56 pm
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