PETG is part of the family of polyesters, and is defined as thermoplastic resin. PET represents the polyethylene terephthalate (the same used for plastic bottles) and G means that it has been glycolized. Modified for longer life. Therefore, it is recommended, for qualitative 3D printing, only to use it in PETG form. This polymer, due to its intrinsic characteristics, is gaining ground in 3D printing and is replacing ABS at home.
The trend is not random, it is mainly due to the advantages that emerge in the direct comparison.
Here some features:
Odourless: it is completely odourless, a fundamental characteristic for domestic use, even if odourless does not mean non-toxic.
Low shrinkage rate: keeps measurements faithfully cooling, ideal for large prints.
Hydrophobic: Does not absorb water, and therefore does not substantially deteriorate
High impact resistance: The high strength makes it the ideal material for everything that moves, including quads, remote-controlled cars and robots (although it can be scratched easily).
High mechanical strength and excellent flexibility: ideal for use with mechanically stressed objects, it is a hard, extremely durable and flexible material. This is also due to an excellent adhesion coefficient between layers. This makes it unsuitable for printing on too many substrates. The very strong adhesion between layers means that these are not so easy to detach when the print is finished.
High chemical resistance: extremely resistant to the action of chemical agents, acids and alkalis.
Typically PETG is translucent, which gives the object a shiny surface finish.
But what does this mean for practical applications? Which objects are ideal for PETG printing?
As we have already said, it is indicated for chassis or bodies of land, water or radio-controlled flying vehicles. Or it can be used (almost all PETGs – read the specific sheet) for objects that must be in contact with food, for everyday household objects, for tools. Basically everything provided that we do not need a particularly rigid or soft material. The typical flexibility may be too much for some applications or too little for others, where TPE and TPU flexible filaments intervene.
How to print PETG:
As with all materials (the only one except the PLA), it is difficult for us to achieve excellent results after just one or two prints.
So you have to approach with curiosity and willing to sacrifice a little time and material to make tests. Obviously in this article I will try to give you an address but as you can easily see by reading our reviews of PETG filaments, the parameters can change a lot. From brand to brand as well as from machine to machine.
My advice, which is not only valid for PETG, but for all the tests that you will carry out on any type of filament is to equip yourself with paper scotch and note directly on the reel the parameters used and results obtained. It may seem easy to remember the settings but after a while and with different materials it may not be. With a minimum of effort you will have a diary of the tests carried out directly on the material, so as not to repeat the same error several times!
I can tell you that even if PETG does not suffer from warping like ABS, it can rarely occur. The problem of PETG, basically the only one, is an acute sensitivity to stringing. This is due to the high viscosity of the material in liquid form.
GUIDE PETG: SETUP AND PRINT PREPARATION.
Guide PETG: Printing Surface
Let’s start by saying that PETG can be successfully printed on any surface, on blue tape, glass, steel and aluminium. We can help the adhesion with slim, various types of glue and strong lacquer. I normally mold on glass or stainless steel with a veil of lacquer without any particular problems.
Guide PETG: Pre settings
PETG requires more space between nozzle and plate for the first layer for optimal printing, so it is recommended, when possible, to increase the offset Z leaving more “breath”. The ideal is to double the set layer line. So, for example, if we are printing at 0.2 mm, we must set the offset so that the first layer has 0.4 mm of space. This process is not always possible and if you are going to do a single PETG print to return to other materials it may not make sense to mechanically modify your printer.
Leave the settings as they are and if you are sensitive do not look at the first layer printed on which the nozzle will smear, within 10/15 layers your print will be perfecta.
Guide PETG: Ventilation
During slicing you can decide how you want the layer fan to work. Extruding this material the fan is set according to the result you want to obtain.
Absence of ventilation is equivalent to firm layers, maximum ventilation with greater definition of the details. In principle I recommend ventilation between 50/60%.
Obviously, the fan must not be activated for the first layers. The Care settings guide explains how to let the layer fan in gently, and thus avoid a series of problems.
Guide PETG: Temperature
Now let’s get to the temperatures. PETG extrusion can vary greatly, from 220°C to 245°C, depending on the brand of the filament, the printer used and the result we want to obtain. Of course, the higher the temperature, the more compact the object is, but with a greater possibility of creating wires; on the contrary, the lower the temperature, the more defined the object is, even if it is more fragile (even if it is never fragile).
As far as the temperature of the plate is concerned, the recommendations must be followed. Normally a temperature of about 70° is recommended, even if the new mixtures can be printed even when the plate is off.
Personally I have given myself the rule to print the first layer at 70° and turn off the plate for the following ones. I explain how to set this option in the third Care Guide. If you intend to turn off the plate it is recommended to insert a Brim from 4 to 8 mm in the print, depending on the size of the model.
Guide PETG: Speed
The printing speed must also be kept to a minimum. The more elastic composition means that you can print without problems up to 50mm/sec and gives more and more problems by increasing this speed.
I therefore invite you not to exceed the speed of 50mm/sec.
Guide PETG: Possible issues
The only recognised problem with PETG is a tendency to string. Especially at high temperatures, due to the very viscous composition of this material in liquid form.
The online PETG documentation also describes possible episodes of over extrusion. So I mention this problem even if I have never encountered it myself.
Surely it has to be said that slowly that 3d printing is advancing also the filament producers improve the production eliminating any problems typical of the material.
If you should happen to have leaks or leaks you just have to decrease the flow by a percentage, typically 5% at a time.
After a few tests, the reading of this guide PETG, the printing will become routine. You will love the characteristics of this material! No smell, no shrinkage and excellent strength are some of the properties of this material.
Buying a brand of excellent quality will make it even easier to print this material. I suggest you read our reviews on PETG filaments, where you will find all the useful information!
I hope I’ve unraveled your doubts about the applications and uses of this multifaceted filament, if you have any other questions please explain them in the comments!