Can You Print PETG Without a Heated Bed? (Solved!)

Without a doubt, heated beds are a significant advancement in 3D printing technology, allowing us to print an extensive array of filaments without issues such as warping and bed adhesion that often happen due to the rapid cooling of the plastic once it touches the build plate.

On the other hand, as heated beds aren’t present on every 3D printer, enthusiasts who own printers without heated beds often wonder which filaments they can and which filaments they can’t successfully print with their printers.

Today’s topic will be the relationship between PETG filament, the second most popular type of filament right behind PLA, and heated beds, where we will find out if it’s possible to print PETG successfully without using a heated bed.

So, can you print PETG without a heated bed?

While it’s possible to print PETG without a heated bed, the absence of a heated bed can make it challenging to get the plastic to adhere to the bed and prevent it from warping, especially if you plan on printing larger models or models with functional purposes.

Moving forward, we will dive deeper into whether you can print PETG without a heated bed or not, take a look at the advantages a heated bed brings to printing PETG, and share some pointers that will come in handy for printing PETG without a heated bed.

Can You Print PETG Without a Heated Bed?

While it’s common knowledge in the 3D printing community that it’s possible to print PLA successfully without a heated bed, there is more discussion and a higher amount of questions in the case of PETG.

We highly recommend using a heated bed for printing PETG, but this doesn’t mean that it’s impossible to obtain successfully printed 3D models without one, especially in scenarios where the models are more suitable to be printed without a heated bed.

When it comes to the suitability of the models, the first factor is the size.

As a rule of thumb, the chance of having trouble with bed adhesion due to uneven cooling increases as the model gets larger. Because of this, printing models that are smaller in size are more likely to yield successful results without a heated bed.

Another thing to look out for is the use case of the 3D printed model.

Since it’s harder to print models with strongly bonded layers without a heated bed, you are more likely to face problems with functional models. On the other hand, models with cosmetic purposes are more likely to yield successful results.

Even though success is definitely possible without a heated bed, there is no denying that you may have to go through a few failed prints before finding it, as printing PETG without a heated bed means that the printing process will be less forgiving in terms of bed adhesion and warping.

What Are the Advantages of a Heated Bed for Printing PETG?

Even though it’s not a complete necessity in every case, we can’t deny that a heated bed brings considerable advantages to the printing process when printing with PETG filament.

The primary advantage of a heated bed for printing PETG is the increased bed adhesion strength it brings to the table by slowing down the rate at which the first layer of the model cools down.

With an increase in the strength of bed adhesion, the chance of another significant issue that frequently troubles 3D printed models, known as warping, is also reduced.

To understand how a heated bed can bring these two significant advantages to the printing process, we first need to dive into thermal expansion and thermal contraction.

In a nutshell, thermal expansion and contraction are two phenomena that affect PETG during the printing process.

While the former refers to an increase in the dimensions of the plastic when it rapidly reaches higher temperatures, the latter is the opposite, causing the plastic to shrink as it rapidly cools down from the high temperatures.

Among these two phenomena, thermal contraction happens when the plastic comes into contact with the build plate, as the build plate is much colder than the temperature of the PETG that recently came out of the nozzle.

Essentially, thermal contraction causes the plastic to pull away and detach from the build plate, as when the plastic contracts, it starts pulling its edges towards the center.

The effect of the heated bed comes in at this point, where the higher temperature of the build plate reduces the severity of the thermal contraction PETG undergoes, preventing the force of the thermal contraction from pulling the plastic away from the surface.

How to Print PETG Without a Heated Bed?

As printing PETG without a heated bed increases the likelihood of something going wrong with the printing process, there are some vital points to consider to compensate for the absence of heat on the build plate.

Since the purpose of the heated bed is to get the PETG to adhere to the build plate by preventing the first layer from cooling too quickly, the primary thing we need to compensate for is the reduced bed adhesion strength to print PETG without a heated bed successfully.

The primary way to increase the strength of adhesion between PETG and the build plate without a heated bed, as you may imagine, is using a build surface that PETG will stick to as firmly as possible to counteract the severity of thermal contraction.

We recommend using a PEI build surface for printing PETG without a heated bed, as PETG sticks very well to PEI surfaces, and sometimes, even to a fault where it becomes pretty hard to get the plastic off the surface.

Another thing that can help increase the strength of bed adhesion is using adhesives on the build plate.

Applying adhesives such as blue painter’s tape, glue stick, hair spray, or masking tape to the build plate is a common way to increase the adhesion between PETG and the build plate.

While we would recommend using blue painter’s tape among all the adhesives, it’s worth noting that many members of the community report having success with different options.

Wrapping Up

Printing PETG without a heated bed is definitely a tricky subject with differing opinions in the community, especially compared to printing PLA without a heated bed where everyone seems to agree that it’s possible.

To quickly recap, we can say that it’s entirely possible to print PETG without a heated bed, but it would be more challenging due to the absence of advantages that a heated bed brings in the bed adhesion department.

While larger prints and prints with functional purposes are more prone to be affected by the lack of a heated bed, you can most likely get away with printing smaller, purely cosmetical models without any issues.

Happy printing!