Category: Filament

I’ve printed parts in the past that end up looking like something was dragged across the surface while it was printing. In reality, something may have been dragging across the surface. The first thing that I check when this happens is to make sure that the nozzle is clear. This is a typical sign that the nozzle may be clogged.

If it does turn out to be clogged, I do a “cold pull.” Heat the nozzle up 20 – 25 degrees past what you use it at during printing. Then let it cool completely. The idea is that any debris will collect into the filament. Once it is cool, heat it up again but tug on it from the extruder end. It will break loose from the nozzle at a much lower temp than what you print at. Hopefully, any debris that was clogging the nozzle comes with it. Just cut the end of the filament off and feed it back in.

Sometimes I print parts that have a top surface that look like a riverbed. There are valleys and branches going all across the surface of the part. This is usually a result of the nozzle being too close to the bed. Mechanically, there is too much filament coming out of the nozzle for the amount of space between the bed and the nozzle. When this happens the filament flows into other areas of the print and creates these valleys.

In short, your nozzle is too close to the bed if you have this. Adjust the height or redo your bed level.

Some 3d printers end up with rough top layers. One thing that you can check if this happens to you is the rate of filament flow. Filament flow is affected by a couple of things, the most common issues are:

  • Flow rate setting in slicer. I normally set my flow rate to 105% – 110% for the first few layers, then turn it down to 100%. If this is set too high then your printer is adding more filament than you might need, resulting in a rough surface.
  • Extruder calibration. Run a simple extruder calibration to double check that you are extruding the amount that you think you are. If you are overextruding, you might be causing problems for yourself.

“My filament keeps snapping off!”

I hear this a lot. This is almost always the result of too much tension on the extruder. Most extruders have a knob that is used to adjust the amount of tension on the filament. Too little tension and your filament slips and you will have underextrusion issues.

Too much tension and your filament will look like it has bite marks on it or even snap off. Find the sweet spot in between.

Filament, or rather, improper use and storage of filament, can cause a lot of issues. 

Most of it is porous. What this means is that it will absorb moisture over time, especially in humid areas. If you do end up using wet filament, you might notice a couple of things. It might pop or bubble as it is extruded as the moisture boils. It might extrude with holes in the filament for the same reason. Almost certainly, your printed part will have a very poor surface finish.

To remedy this, store filament in a dry area and, as an extra measure, dehydrate it before use.

I had a project a little while back for which I wanted to use wood filament. After running a few test parts, I decided that I needed to increase the nozzle diameter because the wood filament kept clogging my off-the-shelf 0.4mm nozzle. After installing my larger diameter nozzle I ran a few more test parts and noticed that my corners weren’t closing properly. After going through many hours testing to find out what the cause was, I realized that my retraction was off. I had to decrease it significantly to get everything to work right again.

Moral of the story, most parameters are specific to the exact configuration that you have on the printer. If you change anything, you should check to make sure that you temperature, retraction settings, speeds, etc. are all appropropriate for the new configuration, or adjust them.

Are you printing thin parts that wind up being see-through in certain areas? 

For taller prints, it’s usually not a problem as the criss-crossing patterns from the slicer will ensure that your print is eventually filled in all the way. But for thin prints, it can be problematic to have a print with gaps in the ends. When I’m printing thinner components, I typically enable Cura’s overlap function. There is a “skin overlap” setting, as well as an “infill overlap” setting. I like to leave skin overlap at 10% and the infill overlap at around 30%. This is technically just overextruding under a different name, so you specific slicer may have a different name for it.

Easy to work with, biodegradable, inexpensive, can be infused with different materials to introduce different properties; what’s not to like about PLA?

I like to use PLA. It’s a good filament for a variety of uses, and I use it for probably 80% of my prints. But it’s not a one-size-fits-all. I like to use it for a lot of proof-of concept ideas that I have had or to experiment with different versions of a component.

Some of the downsides of using PLA, you need to be careful of which manufacturer you purchase from. Not all PLA is created equal. Some manufacturers put in cheap additives to keep their costs down. Then these additives end up causing problems with your prints. Find a good brand, dial in your printer for that brand, and stick with it.

Compared to other materials, PLA has pretty poor thermal properties. It your component is going to be anywhere near any type of heat source, PLA may not be the right material for you.

PLA doesn’t hold up very well outdoors. 

PLA, has pretty poor hardness properties. 

As with so many things, it depends on what you are doing. For the right application PLA is great.

I recently designed some parts that need to be structurally stronger than any of the plastic components that I have designed in the past. I set out to find something, I was hoping for a metal filament that I would be able to print with my FDM printer.

I was not disappointed. I discovered BASF’s Ultrafuse metal filament, which is PLA infused with metal. It’s not cheap, so I’ll be doing quite a bit of investigation before I start using any of it. It also requires post-processing to remove the plastic from the metal and to sinter the metal together afterwards. I also need to plan for 20-25% shrinkage. All in all, this should be an interesting experiment.

Sometimes people post wondering why their prints come out horribly.

They will adjust their settings and tune them to a specific brand, color, and type of filament. Then, after a little while, they change something minor, like a different color from the same brand and their prints get all messed up. It takes different additives to make different colors. In the 3d printing world, yellow is different than red, which is different than blue. The different additives from the colors cause the filaments to behave differently when melted, which in turn results in different looking 3d prints. You must tune them each individually.