Why Don't People Like PETG?
To understand the problem with PETG, we have to start from the very beginning. Let us first understand a bit about the technology and competing materials like PLA and ABS.
3D Printing Technology
3D printing has been around for close to four decades. Over the years the technology has seen massive developments that have transformed the technology from a rapid prototyping tool to manufacturing technology. The developments have brought asense of stability, reliability, and repeatability to the overall process, especially the FDM/FFF 3D printing technology.
FDM/FFF 3D printing technology
The FDM/FFF (Fused Deposition Modeling/Fused Filament Fabrication) technology was invented in the late 1980s. The technology uses thermoplastic polymer filaments which are heated and extruded through nozzles and deposited onto a build platform in a layer-by-layer form to build objects.
Since the invention of this technology, the principal materials of usage and experimentation have been PLA and ABS. They have undergone numerous upgrades to ensure their reliable printing. We can safely say that since the early last decade, the printing results have been more predictable and have only gotten better over the years. Today PLA and ABS are the most widely used materials in the FDM/FFF technology.
3D Printing with PLA and ABS
Users have worked on both these materials for most of their 3D printing needs. PLA (Polylactic Acid)is a biodegradable material and offers above-average strength and toughness. PLA is hands-down the easiest material to print with. It melts at 190OC,easily sticks to the build platform, does not require a heated bed, and is not prone to warping or cracking.
ABS (Acrylonitrile Butadiene Styrene) is an industrial material that is lightweight and shows good impact resistance at low temperatures. However, ABS is a tricky material towork with. It melts at temperatures above 210 OC, does not easily stick to the build platform, requires a heated bed, and is prone to warping and cracking. But since these are well-known issues with ABS, by carefully adjusting the slicer parameters and managing the stickiness of the bed, these issues can be resolved to produce a successful print.
Both these are used by almost all FDM 3D printer users. It is obvious then that users now know how to get a successful print with these materials.
PETG is comparatively a new entrant in the FDM 3D printing materials family. Not many people are truly aware of this material and those who know have a hard time printing as PETG also has certain printing issues similar to ABS. It is often found thatthere is a resistance to shifting from PLA/ABS to PETG as there is a learningcurve involved.
3D Printing with PETG
PETG is a thermoplastic polyester material that has the same chemical composition as PET(polyethylene terephthalate). The addition of the glycol only reduces its brittleness making it a better material. It is 100% recyclable and exhibits better strength properties than ABS.
On the flipside, PETG has multiple issues like warping and cracking. It, therefore, requires a heated bed thus requiring a hardware upgrade. Additionally, it melts around 240 OC to 260 OC (depends on the brand) so again the nozzle has to sustain such high temperatures for a longer duration of time. Besides these issues,PETG also has other issues which will be discussed ahead.
Now that we have understood the background of the technology, all the materials in question, and their basic advantage and issues, we will move towards our agenda to find the reasons why don't people like PETG?
What people hate about PETG?
We list down some of the popular reasons why people dislike PETG.
Higher Cost than PLA
Sometimes it simply comes down to the cost of material and the impact it has over a longer duration of time. PETG is costlier than PLA and for enthusiasts, hobbyists, and students who have very tight budgets, it is not easy to shift to new material. A higher cost creates stronger friction to start using PETG over PLA.
Hardware upgradation to print with PETG
As mentioned earlier, PETG melts at higher temperatures and requires a heated bed. A lot of entry-level 3D printers do not have a heated bed. The high extruder temperature also wears down a nozzle faster than a material like PLA that only requires an average temperature of 190 OC. This puts an additional cost on theuser.
First Layer Adhesion issues
First layer adhesion is a typical problem for materials like ABS. Even PETG has the same problem. But while users are working with ABS for a long time, they already know how to successfully print ABS whereas PETG brings along a new learning curve.
Reworking of Slicer Parameters
With new materials, come new slicer settings. Since most FDM materials now have standardized results, new materials like PETG have to be reworked for printing. Fixing settings for successful output is also a challenge as the same parameters may not always result in the best outputs. This issue makes working with PETG tedious.
Minute features are not as easily captured as PLA
PETG is not an ideal material for small intricate features. For applications requiring minute features, PLA is preferred. Most people find such frequent material changes to be painstaking and obtrusive to their work.
Non-availability of good colors
Unlike PLA and ABS,PETG is not available in a wide range of colors. Only a few standard colors are manufactured by most manufacturers and that sometimes poses a hurdle in its use.
PETG has high transparency and this is not always favorable to many applications. Though this transparency is desirable in specific applications, not every user will like transparency in all their prints. This again creates a barrier in its use.
Apart from mechanical properties, PETG has no significant plus-point over PLA. It only brings added printing issues.
No Exponential Superiority
Though PETG has better mechanical properties than PLA, they are not exponentially better than PLA. PLA already has enough strength sufficient for most prints. Most users will switchover to new material only if it has unmatched superiority over the other material. But since that is not the case here, users do not want to switch or increase their use of the new material.
Soft When Hot
It is often found that PETG prints remain soft when they are hot. Only upon cooling do the prints get hard and strong. For users, this is an unnecessary waste of time.
While PLA and ABS also show stringing but it can be easily controlled with a few slicer settings. For PETG, it is difficult to eliminate the stringing issue. This creates a problem for users as every print then has to be carefully post-processed adding to an extra effort and time.
How to Start with PETG?
From our own working experience and from probing tons of 3D printing community forums on the topic, we have come to a simple guideline for new users who want to try out PETG but don’t know where to start from.
For basic prototyping, test, or artistic parts requiring intricate details, indoor use, and parts requiring a multitude of colors, use PLA.
For functional parts that require a higher temperature resistance or those parts that require glossy finish (can be achieved through acetone vapor), use ABS.
For functional prototyping, slightly better strength than PLA and transparency requirements, use PETG.