Category: Filament

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 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.

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.

https://www.thingiverse.com/thing:49276

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.

 

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:

  • ensure that your bed is very clean. I use Isopropyl alcohol with a lint free cloth for PLA
  • make sure that your bed is level to the frame
  • in the wintertime, I usually increase my extrusion temperature by about 5 degrees. Your results may vary, so experiment with this on your own machine
  • enclosure, if you feel like you need a jacket, chances are that your 3d printer needs to be warmer too

Ideally, you would have a drive system for your filament that is:

  • lightweight
  • responsive
  • durable
  • does not obstruct or adversely affect movement of the printhead

Unfortunately, you have to choose. You can’t have all of these qualities. Each setup has pros and cons and every 3d printer needs to decide what is best for them or accept what their printer comes with.

A Bowden system mounts the extruder off to the side of the printer frame, allowing the printhead to be more lightweight, which allows higher speeds and acceleration. The tradeoff is that you have a tube that connects the extruder to the printhead, which makes accurately controlling the amount of extruded material more difficult (think trying to turn off a lightswitch with the end of a broom handle).

A direct drive system is just the opposite. You get more responsiveness with your extruded filament, but you are adding weight to your printhead.

If frequency were the only indicator, you would guess that printing different versions of the Venom Symbiote was my favorite thing to print. I’ve printed green ones, black ones, and in this case, I printed a transparent one.

I had to completely rebuild my hotend after this one, over a very simple mistake.

I had purchased a new hotend (complete) to replace one that I was having problems with. I put it on my printer and started printing and you can see the results for yourself.

What I forgot to do is “hot tightening.” When assembling the hotend together (at room temperature) you screw in the nozzle and the heat break until they touch. My heat sink also has some setscrews that need to be tightened. At room temperature, everything is tight. However, when things heat up and expand, little gaps in between each of the components will occur. The solution to this is to heat up your hotend to around 20 degrees beyond what you intend to print at, and then finish tightening the components.

Supports can be tricky, at times. Make them too close and they fuse together with your print and are difficult to remove and leave a nasty surface finish. Make them too far from your print, and your print has nothing to build on. So, how close is close enough but not too close?

Run a tolerance test for your printer. You can find several parts to print that will help with this. Most are some type of widget that prints several different pieces with various gaps in between the parts. If your gap at .25mm is fused together on the tolerance test part, then your machine tolerance is about .25mm and you can’t expect it give you better accuracy than that. Going back to our supports, you can’t place supports closer than .25mm or they will fuse to the part.

To improve this, calibrate your machine.

After trying to print a QR code over the weekend, I decided to tune in my retraction settings. Step 1, I printed a retraction tower. I printed a tower with different levels, with retraction distance set at 0mm, 2mm, 4mm, 6mm, 8mm, and 10mm.

2mm of retraction was a clear winner for my machine, so I decided to dial it in more. I printed another tower at 1mm, 1.5mm, 2mm, 2.5mm, 3mm, and 3.5mm. 2mm was again the clear winner for my machine, so next I decided to play with the retraction speed settings. Most source recommend a retraction speed of 35-40mm/s. I printed a retraction tower with speeds of 30mm/s, 35mm/s, 40mm/s, 45mm/s, 50mm/s, 55mm/s. 40 and 45 both looked pretty good so I printed another one that ranged from 39mm/s – 44mm/s.

Judging from the towers that I printed, my optimal settings are 2mm at 42mm/s.