How to: Printing with PETG filament and how to make it work for you.
Quick print guide to success.
- Platform temp should be between 60 – 90 degrees
- Extruder between 225 and 255 degrees
- Platform should be clean and free from debris – possibly an adhesion promoter like PVA glue.
What is PETG?
PETG – Polyethylene terephthalate glycol is also called PETG or PET-G. It is a thermoplastic polyester that provides a strong chemical resistance is durable and is excellent for manufacturing. Because of the low forming temperatures, it is also excellent for vacuum forming.
One of the most common items you will find that is made from PET or PETG is the common drink bottle you buy from the shops that contain lemonade or cola.
PETG is resistant to UV light and is great for outdoor applications and is commonly referred to as food safe. Aurarum does not rate any filament is food safe. Although the material itself may be food-safe the equipment used to make it is not sterile, the packaging it comes in is not sterile and the printer you use at home is not sterile.
To claim filament is “food safe” is simply a lie.
PETG is known for its vibrant and brilliant colours.
Why use PETG?
Simply because of its ease of printing and durability of the material.
As a 3D printing material it combines the best parts of ABS filament (its mechanical properties and rigidity for practical parts) and the simplicity of printing with PLA – it is a case of the best of both worlds.
It is a truly flexible 3D printing filament that is suitable for making consumer products that require strong material properties.
What are the downsides to PETG?
It can collect moisture onto the spool from the air around itself and this affects the quality of the print. PETG is hygroscopic and needs to be stored in a cool and dry environment to ensure consistent and reliable printing outcomes. It prints better when it is dry and is stronger. Vacuum sealed bags are best with the addition of a desiccant pack to remove any moisture from the air and will continue to keep the filament in good condition for a long period when not being used.
Can I print with PETG?
The answer is… it depends on your printer and extruder. To print with PETG you will need to be able to print up to 260 degrees at the hot end and have a heated bed up to 90 degrees.
If you cannot do either of these then the answer is probably not.
You may also need to modify your printer to make it work with PETG filament but consulting the manufacturer before touching anything is always a good idea.
An all-metal hot end like these units from DyZEND are designed to print materials like PETG with a minimum of fuss.
As a filament, it may also require a little more “tuning in” than the likes of PLA or ABS. Printing out a temperature tower to see the print results before going to full prints will often produce the best results. A temperature change of just a few degrees with PETG can make the largest of changes to the outcome.
What is my print telling me?
PETG is great for telling you what it is doing with your model. If the print is not hot enough you will see clear delamination of the layers or the hot end will constantly jam up. If the print is too hot you will see excessive blobbing and stringing and spider webs will be prevalent. A temperature tower is your friend!
The first layer…
The same is true of many filament types but PETG can be a little harder to get down properly – getting a great first layer can be simple for some – a perfectly level bed is always the best way to start but some other proven methods have been successful for us over our 3D printing journey.
- Painters tape
A disposable surface that works when it is either hot or cold, PETG seems to love this stuff. PETG can bond well to most surfaces and sometimes a little too well. This removes that issue by creating an easily removable surface.
For a glossy finish on the base of the first layer, glass is smooth and will require some adhesion promotion to assist with sticking.
- ABS Glue / Glue Stick
A thin layer of glue is great to make sure the first layer stays stuck down – but aware it can also create a mess that will need cleaning up with chemicals.
- Build plates
PEI is one of the most flexible print surfaces – it works well with PETG – sometimes a little too well and can permanently bond.
If your printer will not stick to the bed check your temperature again, try a combination of the above (eg. Painters tape with a smear of gluestick) and triple-check that your nozzle is the correct height from the build surface.
The edges are curling up and lifting off the bed
PETG can suffer from edge curling and lifting like ABS but to a much lesser degree.
If your models are lifting the first course of action should be to adjust the surface temperature up and down to level the temperature out. This will usually resolve the issue but if that fails you can also try a small smear of glue under the corners or the blue painter’s tape under the entire model.
Should I use a fan?
Like with PLA the first 3 layers should be laid down with no fan and the consensus is a fan speed between 10 and 30% should suffice for the remainder of the print.
Not enough fan will increase stringing and blobbing and too much fan will hinder layer adhesion.
Does it smell when printing?
A little yes but no more than PLA. It is not at all like ABS / ASA or other High-temperature filaments.
1/ Keep the filament well stored
2/ Check your build surface
3/ Double check your temperatures
4/ Try using your fan on slower settings to get better adhesion
5/ Building or a raft with PETG produces great results
6/ Trial multiple build surfaces to get the best results