Problem with overhangs?  

RE: Problem with overhangs?

Torture prints are designed to be difficult, to test the printer to the limits.  If you are new to 3d priting leave them alone for a few months.

During the first few weeks of use the new printer will run-in and settle its parts together; then you will have to go over the basic maintenance checks, lubricate and recalibrate. Even if you got everything dialled in perfectly today, it would all need re-doing.

Better to settle, temporarily, for a basic working printer and get some useful printing done, make your early mistakes, establish a routine and generally get used to the process. Then when you do your one month service you can take extra care knowing the new settings on your now stable printer are likely to last for several months.

Cheerio,

RE: Problem with overhangs?

@diem

Thanks for the reply.

I understand what you're saying, but some of the printing defects are still... troubling. If you look at the image collection the 0.4 and 0.5 "print in place" sections (last two images of the collection), they have some very significant layer issues. Also, I have printed several other things without issue, or without the huge issues I'm seeing here, anyway.

RE: Problem with overhangs?

Posted by: @reaper6971

[...] I understand what you're saying, but some of the printing defects are still... troubling. If you look at the image collection the 0.4 and 0.5 "print in place" sections (last two images of the collection), they have some very significant layer issues. Also, I have printed several other things without issue, or without the huge issues I'm seeing here, anyway.

To troubleshoot specific features, I'd recommend using a small test print that can be printed in a few minutes rather than a complicated, hours-long "challenge" print. Those are fun but are really meant to measure results. For overhangs, I like the "Atom 80" overhang test.

A few things to consider:

• Overhangs are all about temperature. Temperature is all about heat and cooling. The lower the initial extrusion temperature and the fast it cools, the better overhangs will look.
• Overhangs will never look as good as the rest of the print. There is less underlying layer to "squish" against, so extrusions have a more circular rather than squashed oval/stadium cross-section. They tend to look loose and a bit stringy. 
• Most filament manufacturers tend to recommend a range of temperatures with a high end that will allow most users with most setups to get good results. They do this for support reasons. For quality, you can usually get by with using lower temperatures. I find most PLA prints fine at 190C.
• The orientation of your part cooling fan duct matters. Be sure it is aligned to blow on the nozzle area -- and not the heater block -- as much as possible. There are alternative duct designs that might yield better results.
• Cooling can be uneven, again due to the duct design. If results improve if you rotate the part 90 degrees on the bed, definitely look at your cooling setup.
• Lower layer heights will improve overhangs. Wider extrusion widths will also help. The percentage of the overhang that is supported by the underlying layer is important. With wider, lower extrusions, a great percentage of the overhang is supported. Consider using modifiers or variable layer heights on overhangs if using lower layer heights overall is impractical.
• Some filaments tend to print in a more fluid state and will simply be more difficult to get good overhangs with. Experiment until you find a filament you like.