Ever noticed that every spool of 3D printable material, especially plastic based ones, has an optimal printing temperature range on it. For example-
- PLA – 180 – 230°C
- ABS – 210 – 250°C
- PETG – 220-250°C
But why is this the case? What will happen if we go above or below these temperatures provided on the spool? How to know the temperature conditions during the printing process? And even if there are no visible differences in the final product, what consequences can the sub-optimal temperature have, and how to detect it?
That is the agenda we are going to cover in this article.
Why does temperature matter in the first place though?
In fused deposition modeling (FDM), which is the most common way to 3D print, we rely on the adhesion between the layers, which happens because the temperature extruded from the nozzle is very hot, as it needs to achieve flow easily.
Hence nozzle temperature comes into action, for it is the final piece of the printing machine through which the material passes before it is incorporated in the final build, and also because this nozzle is responsible for heating the material to its optimal temperature.
Also worth pointing out at this stage is that, even though we’ll be discussing nozzle temperature and its effects, it is not the only contributing factor to a successful build. As factors such as bed temperature, deposition speed as well as time between deposition of the layers also plays a key role in determining the final quality of the build.
What happens if the temperature is too low?
If the nozzle temperature is too low, the spool material might not even melt in the first place, or even if it does, the flow might not be enough to properly work on the build.
Both of these cases will lead to little to no adhesion between the layers hence leading to the failure of the build.
What happens if the temperature is too high?
At temperatures beyond the recommended range, those materials might tend to deteriorate, as a consequence of which, the layer adhesion might be sub-optimal, leading to structural challenges, or at worst, entire failure of the build.
How to know about the wrong temperature effects after printing?
Having just established that printing temperature matters, we’ll now focus on how to know if the temperature was optimal during or post-printing.
If the temperature is too cold, you might not even be extruding enough material to form a laminar flow, or even if you are, the layers might not be adhering properly.
At this point, you might want to ramp up the temperature in order to achieve proper flow, then print a small part and break it. The broken part will tell if the part printed was one solid part, or just a complex of somewhat put-together parts by looking at the granular structure. If it is stringy, then you might want to increase the temperature a bit more, otherwise if everything seems solid, you’re good to go.
If the temperature is too hot, but not hot enough to degrade the plastics, then you might be extruding too much material, as a result of which, the final build might not look as clean as it should, or the worst-case scenario, it might come out as blobs rather than a well put-together build.
For correcting this, follow the same procedure we used for the case when the temperature was too cold, but first decrease the temperature and then improvise and adjust according to the outcomes of the build.
Why does the same temperature not work everytime?
Assuming you want to translate the same temperature to another build involving the same material, the same temperature might not work for other printing rigs.
This is because there is a difference between the heating block (the part which does the actual heating process) and the tip of the nozzle (from where the material is extruded), hence why there is a range of temperatures given on the spool rather than a set-and-stone number, because this difference in distance can cause changes in temperature of material being extruded.
Other factor that matters
As we stated earlier, nozzle temperature is the most influential factor for the success of a print, but that does not mean that other temperature related factors don’t make a difference.
Some of these factors are –
- The base layer on which the build happens, also known as bed, contributes to how the first few layers are laid out.
- If the bed temperature is too low, then it might result in the first few layers not sticking well, even if the nozzle temperature is optimal, leading to a domino effect on the subsequent layers, eventually failing the build.
- If bed temperature is too high, it might lead to formation of blobs, even if the nozzle temperature is perfectly fine, which will lead to the build sticking almost too well, and that might lead to damaging the end product during the removal process.
- This problem can be solved by preparing the bed as a part of the calibration process of the printing rig.
Duration between deposition of layers
- If the time between deposition of layers is too high, the plastic might cool too much, leading to the new layer not adhering as well to the old layer.
- If the time between deposition is too low, the former layer might not have cooled down enough, again leading to adhering problems.
- Most 3D printers do have a fan as a part of the printer, which is used to regulate the temperature to keep this effect to a minimum. You just need to tune the fan to keep the temperature inside the build constant.
Although this is not an exhaustive list of the other factors that come into play during the build, these ones are the most common reason as to why a build fails.
Proper calibration of the printing machine is imperative to the success of 3D printing, and most of that setting happens in the form of temperature regulation.
Nozzle temperature is arguably the most important temperature-related factor, but as we have seen, other factors also play a key part in deciding the quality of the final product.
We recommend building some small prototypes across a variety of temperatures and breaking them via tensile strength to see if the build passes the quality you expect from them. This also allows you to see the optimal temperature for your printing rig with that material.
Also worth pointing out is the fact that as these prototypes will be relatively small to what you might actually want to print, take into consideration the time between deposition of layers.
Also read: Tips to improve 3D print quality