Blobs issue  

Likely overhangs

If those hex shaped openings are hollow tubes, you're likely seeing defects due to overhangs. A lower layer height might help.

Save your current  3MF project file, zip it up, and attach it to a reply here so we can see your part & settings and give better recommendations.

Project file

Thank you for your reply. Please see attachedHolder V2 Forum.3mf

Try calibrating extrusion multiplier

Ah, OK. Not overhangs at all. You've got some over extrusion on the inside of the hollow hex tube.

• I'd start with calibrating your extrusion multiplier to be sure it's not just putting out a bit too much filament. If your printer is not a Prusa, have you done an e-step calibration?How do the outside walls look?
• You've got 50% fill density set which can aggravate over extrusion with a small print. How does it look with 15%?
• How does it look with 2 perimeters?
• Your printer preset is named Creality but looks to have Prusa gcode. Is it working OK otherwise?
• I notice you've got Print Settings->Multiple Extruders->Ooze prevention turned on from the default off. This shouldn't cause any problems, but worth flipping just to be sure.

RE: Blobs only on the inside

Posted by: @bobstro

Ah, OK. Not overhangs at all. You've got some over extrusion on the inside of the hollow hex tube.

• I'd start with calibrating your extrusion multiplier to be sure it's not just putting out a bit too much filament. If your printer is not a Prusa, have you done an e-step calibration?How do the outside walls look?
• You've got 50% fill density set which can aggravate over extrusion with a small print. How does it look with 15%?
• How does it look with 2 perimeters?
• Your printer preset is named Creality but looks to have Prusa gcode. Is it working OK otherwise?
• I notice you've got Print Settings->Multiple Extruders->Ooze prevention turned on from the default off. This shouldn't cause any problems, but worth flipping just to be sure.

Thank you. Do you have a recommended way to calibrate the extrusion multiplier? ( I saw Prusa has write up on this topic) 

I am using the Prusa Mk3.

I tried 15% before, it’s less blobs but it’s still there however the part was not strong enough .

The rest of the part look good on the outside. On the full model, I have multiple Hex slots, the blob problem only shows on the first one. 

A bug

Posted by: @bobstro

• Your printer preset is named Creality but looks to have Prusa gcode. Is it working OK otherwise?

When I open up his 3mf-file PS choose the printer "Original Prusa MINI & MINI+"
Probably this is the same problem as in this thread. You, and I, don't have Prusa Mk3 installed so PS choose the first name on the list, which in my case is Prusa Mini and your case I assume is a Creality printer

If this is the case it's a well known bug that should be fixed in 2.4

Use Prusa calibration article

Sorry, I meant to include the link to the Prusa article. Looks like you found it.

Interesting about the preset bug. I do have a Mk3s preset installed. Sounds like a few things can trigger the bug. Anybody know if a GitHub issue has been opened?

Prusa Mk3

Thanks for the reply. 

I have the Prusa Mk3. I am not sure why it says creality. Was there a work around the bug? 

Tested and verified

Posted by: @bobstro

Interesting about the preset bug. I do have a Mk3s preset installed. Sounds like a few things can trigger the bug. Anybody know if a GitHub issue has been opened?

Yes, but he is having the Mk3, without "s". I installed "Mk3" just a moment ago to test this, again, and it looks like this:

If I uninstall "Mk3" it looks like this:

And it is because "Mini" is the first one in my printer list.
I bet the first printer in your list is a Creality 

If you read the thread I linked to, and look at what and how I tested it you see what is happening.
Yes, I open an issue and it was closed within an hour or two. As said, it has been fixed in 2.4 alpha.
In 2.4 PS temporary install the files that is needed, as seen in This Post

Ignore the bug!

Posted by: @rocky79

Thanks for the reply. 

I have the Prusa Mk3. I am not sure why it says creality. Was there a work around the bug? 

It's not important, just confusing. The settings were for a Prusa which is why I was confused. Don't let that distract you, sorry.

@rocky79

Posted by: @rocky79

Thanks for the reply. 

I have the Prusa Mk3. I am not sure why it says creality. Was there a work around the bug? 

The settings "inside" is correct, it is just the name that is different.
In this particular case it means that all the PrintER settings are for Mk3, even though it, for ME, says "Original Prusa MINI & MINI+", and for @bobstro says "Creality ...".

I don´t know of any workaround beside check if settings seems correct.
If you look at the attached picture, the screen capture is from your file, I have NOT Mk3 installed, the settings are clearly for "MK3" and the name is "Original Prusa MINI & MINI+"?!
This has happened to me several times when I download files from this forum. 

Let's hope for quick release of Prusaslicer 2.4, then all this will be gone 😊 , hopefully 😏 

RE: Inside Walls still not smooth

I am still having issues with the rough texture on the inside walls of the hex shape. The outside finish is good, it’s only the inside. That surface needs to be smooth. 

Any idea how to achieve that? 

BTW, I fixed the blobs issues by disabling the Z retract.