Sometimes I end up printing parts with top surfaces that sag.
One of the things I look at when this happens is the infill settings. The top surfaces bridge across the infill gaps. If they are too far apart it can cause sagging.
Another thing to look at is the number of top layers. Increasing the number of top surfaces can help with this too.
If you do much 3d printing, you will eventually want to use a different spool of filament before your current one is finished. And, unless you live in a desert region, your filament will pick up moisture, leading to printing problems down the road. By the way, even if you do live in a desert, I would still argue that your filament will pick up moisture.
I’ve seen some people dry out their filament and then store it in vacuum bags, then remove it when they are ready to continue printing. My preference is to just store it as-is, then dehydrate it when I plan to use it again. I use a modified food dehydrator to do this. I just cut out the middle part of the racks so that the dehydrator closes around the spool. Other people use purpose built dehydrators or other homemade versions. Airtight Tupperware seems to be popular for storage and dehydration.
Sometimes you will see small holes in your print when viewing the first few layers. This can happen if your line width is set too high. Too high? Wouldn’t I need to increase my line width to cover more of the surface?
Running your parts with a thick line width will cause larger gaps in the “corners” where the nozzle steps over to the next line to lay down. I usually don’t worry about it too much. In most prints, these holes don’t matter and eventually get filled in anyway. However, in cases where it matters, just reduce your line width. Or, even better, replace your nozzle with a smaller nozzle.
Sometimes extruder problems are truly extruder problems. When there is a clogged nozzle problem, your extruder won’t be able to push more filament through and your extruder gears will often start making a clicking noise, leading you to start your troubleshooting diagnosis with the extruder.
For troubleshooting, see if you can isolate the extruder from the nozzle. For a Bowden tube setup, this is pretty simple. Just pull out the Bowden tube and see if the extruder works. For a direct drive system, it’s a little more difficult, but you can just pull of the nozzle and see if the extruder works then. Then, if the extruder suddenly starts working correctly you will know that the problem is with the hotend. If it still doesn’t work, then you know that the problem is with the extruder.
Sometimes, the extruder will start clicking and the filament will stop feeding. This can be a couple of things, I usually start my diagnosis on the hotend, as that is most often where I have found the problem(s) to lie. In my experience, it usually means that I have some type of clog on the hotend side that needs to be cleared.
To clear things up and get printing again, I usually do a cold pull. Then I snip off the first 25mm or so of the filament to make sure that I’m not reintroducing some contamination to the hotend. Then I heat the hotend up to about 20 degrees hotter than my print temperature and make sure that I heat tighten all of the hotend components to make sure that there aren’t any gaps anywhere.
I had a fun project that I did a little while ago. I made a jewelry box for my wife. I bought some wood PLA. After a little bit of testing, I decided that I wanted it to have that wood grain look and so I did some research into finding out how to do that. I found a script on Thingiverse that varies the hotend temperature within a range while it is extruding. This had the effect of turning the filament darker at higher temps and lighter at lower temps, giving my jewelry box a woodgrain appearance. Give it a try if you have any wood projects coming up.
I relearned something important over the Christmas break that I had forgotten. The word “At.” All of your settings only apply at specific temperature, retract settings, etc.
I increased my temperature, but didn’t change anything else. I know better, but I did it anyway. Oh well. Sometimes it takes a few times to learn a lesson. My print started stringing like crazy. The science of what was happening is simple in hindsight. I had all of my retraction set up for a particular printing speed, specific extrusion values, temperatures, retraction settings, etc. When I increased the temperature, it created a situation where my filament became more molten so it was oozing out of the nozzle and stringing everywhere.
I needed to tune my printer to the new settings. Live and (re)learn.
I was reminded recently that temperature and retraction are closely related. I had run a retraction tower and dialed in my settings. Then I ran an actual part in Cura and kept getting stringing. Turns out that I needed to run a temperature tower, then rerun my retraction tower. It’s an iterative process. Setting retraction, but then increasing the temperature (like I did) will cause the filament to ooze out of the nozzle and give you stringing, despite having the proper retraction settings.
I’ve seen too many printers pulling up pieces of their bed along with their print when they go to remove it. There isn’t much you can do about the damaged bed, but you can prevent it from happening again in the future. I have found that such aggressive bed adhesion often is the result of too much “squish” in the first layer, temperatures being too high, or a scored bed surface.
A lot of people are wondering why their prints are not sticking to the bed when they haven’t changed anything on their printer. I’ve mentioned bed leveling many times, but that’s usually the first thing I look at. The other things I look at are extrusion temperature, bed temperature, and bed cleanliness. Many people put their printers in a basement or in a garage. If there are no temperature controls on the environment, it could become a significant problem. A couple of things to look at as the weather starts continues to get cooler:
