3D Printing Help Getting 3D Printer Settings Dialed In

[BigMacDaddy]

I did not see a general thread where people could ask for advice on print settings so I posted this thread.

I am printing with ABS with a heated bed and enclosure (Prusa MK3s). When I print single objects everything goes fairly well. However, whenever I print multiple pieces at the same time I get bad vertical ridges and gaps -- I think this occurs due to the print head changing between parts. I also sometimes get strange spirals of blobs on nose cones - one blob per layer (you may be able to see this on the nose cone in the pictures but this is pretty subtle compared to what I often get). Note: Notch on edge of shoulder is in print to help with alignment on body tubes.

.4mm nozzle, .2mm layer height, 2 external perimeters, 5 top layers, 4 bottom layers, 15% rectilinear infill (most shells are around 3 layers thick), seam position = nearest, external perimeters first (I think this is the issue but when I did not set this flag on I used to get bad outer surface variation / irregularities due to changing shell thickness I think). Speed 45mm, small & external perimeters 25mm, first layer speed 25mm. I can share more settings.



Here is an example of something I printed alone on the bed...



I have just been sanding and filling parts but would love to get my setting dialed in a bit better so that I do not need to do so much cleanup. Thank you in

 

[AeroAggie]

You might want to tune retractions a little bit. I suspect those are the blobs you're seeing. There's some other stuff going on at some of the seams too, but play with retractions first and see how much that helps.

What are your current retraction settings? (speed, length)

 

[Michael L]

If Prusa Slicr

Print Settings
Output Options
Check the Complete Individual Objects box

It'll print one part (completely) at a time

BUT if the objects are too close together and of different heights it may tell you that you can't do that.

 

[BigMacDaddy]

You might want to tune retractions a little bit. I suspect those are the blobs you're seeing. There's some other stuff going on at some of the seams too, but play with retractions first and see how much that helps.

What are your current retraction settings? (speed, length)

Thank you for any help!

Under Extruder 1 - Retraction Length: .8mm; Lift Z .4mm; Retraction Speed: 35mm/s; Retract on layer change: yes;

 

[BigMacDaddy]

If Prusa Slicr

Print Settings
Output Options
Check the Complete Individual Objects box

It'll print one part (completely) at a time

BUT if the objects are too close together and of different heights it may tell you that you can't do that.

Thanks - I have considered this (along with spreading out the objects) but would ideally like to get the settings a bit better if I can as well.

 

[Arpak]

The blobs tend to be where it jumps from layer to the next layer, you might have random z hop on otherwise it tends to place that blob in the same spot making it more like a seam.

 

[AeroAggie]

Your retract settings don't seem that unusual and are very close to what I'm running on my Voron. If you haven't already, turn on the retract, deretract, and seam indicators in the slicer so you can see where those events are occurring. It's not a fix by itself, but helps to visualiize and troubleshoot specific artifacts like this. Then go here and start working through these calibration techniques: https://all3dp.com/2/3d-print-zits-tips-tricks-to-avoid-blobs/

There are a lot of variables that can affect print quality like temperature, extrusion multiplier, retraction, linear advance, and so on. You may need to spend some time to calibrate each of those to your specific printer, though the Prusa profiles generally get you pretty close.

 

[cwbullet]

You might want to tune retractions a little bit. I suspect those are the blobs you're seeing. There's some other stuff going on at some of the seams too, but play with retractions first and see how much that helps.

What are your current retraction settings? (speed, length)

They could also be a leak if your hotend it not perfectly assembled. Look around the top of the heat block for oozing.

 

[Michael L]

I saw a notice for a printer tuning video from the Makers Muse channel on YT. I haven't watched it yet but it might help

 

[beeblebrox]

Make sure you print inside perimeters first not outside. That ooze when a new layer starts can and will cause blobs, you want the blobs on the inside where invisible. If you can have your parts lighter weight, print in VASE mode or Spiral mode. The detail will be much better. Not sure what Prusa calls it. I use Simplify 3D

 

[BigMacDaddy]

Make sure you print inside perimeters first not outside. That ooze when a new layer starts can and will cause blobs, you want the blobs on the inside where invisible. If you can have your parts lighter weight, print in VASE mode or Spiral mode. The detail will be much better. Not sure what Prusa calls it. I use Simplify 3D

View attachment 499591

Thanks - I actually turned on the "print outside parameters first" setting since I used to get strange banding on the outside surface due to changes in thickness of my shells.

You can see it here in the boat tail of one of my earlier rockets, Thunderbird...