As a general rule, all flexible filaments are made of Thermoplastic Elastomers (TPE). This is a blend of hard plastic as well as rubber. Indeed, as the very name suggests, these types of materials are highly elastic in nature. They allow the plastic structure of the filament to be both stretched and flexed very easily indeed.
Before we talk about the best flexible filament, it’s good to know what flexible filaments are.
There are several types of TPE filaments, and Thermoplastic polyurethane (TPU) is the most commonly used amongst all the flexible 3D printing filaments out there. Sometimes, these terms are also used quite interchangeably. The generic terms get mixed along with some of the more popular brand names, such as Ninjaflex.
Here, it is pertinent to note that the flexible plastic-based filament’s degree of elasticity entirely depends on the specific type of the TPE being used. Apart from that, the chemical formulation that is used by the maker or manufacturer of the filament also plays a key role here.
For example, at least some filaments can turn out to be partially flexible like a rigid car tire. However, but on the other hand, several other filaments can also be both elastic and fully flexible at the same time. Think along the lines of a rubber band. Let us take a detailed look at some of the more flexible filaments out there so that you will be able to select the very best flexible filament for your 3D printer.
Best Flexible Filament
1. NinjaTek TPU Filament
This is arguably the very best TPU flexible materials around. It is also known as NinjaFlex, and it is a byword when it comes to flexibility. In fact, it is not only one of the most widely available TPU filaments in the market; it is also justly renowned for being able to create all those truly fantastic “squishy” shapes and prints.
The NinjaFlex TPU flexible materials filament comes with a shore hardness of 85A. That is a serious amount of flex, to say the least. It would not be wrong to describe it as extremely flexible as a wet noodle—the recommended temperature settings for this filament range between 210º and 225º C.
However, there are no recommended settings for the heat bed as yet. As far as printing speed goes, NinjaFlex churns out its prints at a top reliable print speed of around 30 mm per second.
Its manufacturers tout it as the first truly flexible filament that does not require any sort of fill or layer manipulation to achieve excellent performance. It comes in spools that weigh around 1.25 lb each. It can be ordered from the amazon superstore.
It is currently available only in midnight black color
2. Polymakr Polyflex
This is a TPU based material that is remarkably similar to the more mainstream TPE. Albeit, there are certainly important differences between the two. TPU is becoming increasingly more commonly available for all kinds of 3D printing purposes, even though it has only recently burst on the 3D printing scene.
Polymakr Polyflex’s Shore A hardness has been rated at being between 90A to 95A. This can be favorably compared to most of the other commonly available TPU based filaments available in the market today.
Here, it is pertinent to note that the good people at Polymakr don’t really seem to commit to any sort of specific hardness rating for their Polyflex product. This is why it is likely that it might be subject to certain environmental conditions such as temperature and humidity. This might turn out to be an important consideration in case you have any specific requirements for your builds.
PolyFlex has been designed to be fully compatible with just about all of the popular desktop FDM/FFF printers in the market. It does not require any hardware modifications.
Generally speaking, Polyflex tends to print pretty well, and it offers pretty decent service. However, it is important to remember that it is only available on 750-gram spools. Apart from that, it is not offered in any of the more subtle shades and colors. Polyflex printing settings hover at 220 to235 C, so make sure that your 3D printer supports these temperatures before you purchase this filament.
Availability of Colors
The Polymakr Polyflex is available in most of the basic colors, including black, white, red, blue, orange, and yellow.
3. Hatchbox TPU Filament
These highly flexible filaments have been universally designed to be fully compatible with most of the commonly available 3D printers around.
This filament material uses 1.75mm diameter filaments, and each one has a dimensional accuracy of +/- 0.03mm
The makers of this filament claim that it can revolutionize and ultimately reshape the whole of the 3D printing industry.
In fact, this highly elastic filament has been designed for highly specialized prints to create a myriad number of forms and shapes. Hatchbox TPU has many every day uses thanks to its soft and very malleable characteristics every time heat has been applied to it; not to mention its hardness and excellent structural integrity when it is allowed to cool down.
It has a shore hardness of 95A with the A denoting its extreme flexibility. Here Hatchbox’s shore 95A basically denotes that the filament is highly resilient and malleable at the same time. It is also remarkably resistant to abrasion as well. It comes in economic spools of 2.2 lbs each (1 KG approx.) It has an outside dia of 1.75mm, which means it is good enough for most common applications and prints. It will work well with a heated bed.
It is currently available only in silver color.
4. Priline TPU Filament
Priline TPU Flexible filament is constructed with soft and elastic material whose texture and feel are roughly akin to rubber. It is somewhat similar to Flexible TPE, but it is easier to print than conventional TPE. Moreover, it is also much harder (once it has cooled down to room temperature) than its TPE counterpart filaments.
Priline TPU allows plenty of room for repeated movement or impact without the risk of cracking the material of your precious build. Priline offers a refund guarantee in 30 Days if you are not satisfied with their filaments.
It is constructed of TPU Flexible (Thermoplastic Polyurethane) and comes in a spool weighing one KG (approximately 2.20 lbs.). It is a standard 1.75mm Spool Diameter: while the overall width of the Spool itself is 2.83 and the total Spool Hub Hole Diameter measures at 2.20
The recommended Printing Temp and the Nozzle Temperature of the printer are 190-210°C (374-410°F). Apart from that Priline also recommends a Plate Temperature of 50°C (122° F) on its heated bed.
Availability of Colors
This product is available in various colors, including black, blue, green, cyan, gray, orange, purple, red, and white.
5. Overture TPU Filament
This is a TPU based flexible filament that has been specifically engineered to work on just about every conventional desktop 3D printer around.
These filaments have a shore hardness of 95A. In fact, Overture’s TPU flexible materials can be easily stretched up to 3 times more than its original and actual length.
It boasts of excellent bed adhesion, and it is also low-warp and low-odor to boot. All of these qualities combine to make these flexible 3D filaments very easy to print indeed.
Overture TPU has been uniquely designed and manufactured with its very own Clog-Free patent. This is why it is practically guaranteed a smoother and more stable 3D printing experience.
It has a diameter of 1.75mm along with dimensional accuracy + / – .05 mm, and it comes in a one kg spool (2.2lbs)
It has proven to be very cost-effective and efficient with most common 3D printers, such as Ultimaker, Makergear, MakerBot, Monoprice MakerSelect Prusa i3, and more similar 3D printers with a hot end and drive extruders.
Finally, Overture offers a lifetime guarantee for either refund or replacement of any defective product even when used with a vintage direct drive extruder.
It is available in black, blue, red, space gray, white, green, orange, purple, blue, and dark blue colors.
6. Sainsmart TPU Filament
SainSmart Flexible TPU has become a byword for quality and flexibility in the 3D printing world. Thanks to its higher Shore hardness, it is a good choice for your first flexible filament as it is easier much to print than many of the other popular filament brands out there.
It offers excellent bed adhesion, and its standard size spool is capable of easily being fitted on most 3D printers. Since the filament produces some truly tough parts, it is considered really great for all kinds of high-stress objects.
It also prints very well on any regular Bowden extruder, albeit at very low speeds of up to 10mm per second. It is a very decent filament for all types of projects, such as phone cases, drone parts, shoe insoles, and the like.
The filament comes to around a quarter of a kg (250 grams approx.), so it doesn’t flop all over the place. The product is available in 1.75 dia. It is very rigid once cooled, and it can easily be used for objects that take more impacts than normal prints.
It is available in blue, emerald, green, purple, red, pink, and violet.
7. Tronxy TPU filament
This filament I considered very useful for a vast range of printing applications. Since it has the benefit of Low-Odor and Low-Warp, it is straightforward to print. As a matter of fact, when compared to traditional brittle TPU, the material of this one has been adjusted for optimal performance.
Its’ shore hardness is A, 3 sec95, making it ideal for most conventional tasks.
Tronxy TPU (flexible) 3D printer filaments are always produced on state of the art machinery with more precise specifications. This is why they have a maximum tolerance of only +/- 0.05 mm or so. It does not matter which 3D printer you plan on using; the consistently high quality and universally round diameters will always provide an optimum flow of the material through the printer’s extruder nozzle.
As of now, virtually all 1.75 mm-specification 3D printers currently available in the market have been adequately configured to work well with TPU 3D printing filaments.
These filaments are almost completely free from potentially hazardous substances. As a matter of fact, the 1.75 mm TPU filament typically gives off a sweet fragrance that is a good improvement over the smell of hot PLA filaments.
Availability of Colors
This TPU filament is available in only a clear semitransparent color as yet.
TPU Flexible Filament Vs TPE Flexible Filament
TPE and TPU flexible filaments have a few important things in common: they are both essentially thermoplastic derivatives. In layman’s terms, this means that they both allow a new Flexi filament 3D print to stretch and bend easily enough.
TPE is a blend of both hard plastic and soft rubber so that its user can effortlessly utilize both its thermoplastic and elastic properties. TPE basically covers a very vast range of flexible materials that include thermoplastic polyamide (TPA), thermoplastic co-polyester (TCP), and thermoplastic polyurethane (TPU).
TPU stands for thermoplastic polyurethane. It is a new subdomain of one of the more common types of 3D printing filament around. It is a bit on the more rigid side when it comes to comparing flexible filaments. This makes it ideal for tough builds that can take a licking and keep on ticking. In fact, printing with flexible filaments makes it easier to print objects.
What Is Shore Hardness
Shore Hardness may be best defined as a common method of measuring the overall hardness of many different sorts of otherwise soft plastics. The shore hardness of an object or even different filaments will enable you to compare the various materials to safely determine how hard or soft the flexible material might be once the print is completed.
The tech specs for most types of flexible filaments almost always give their shore hardness value. These may range from 85A (softer) all the way to 95A (harder).
Here, the letter ‘A’ will refer to the scale being used. It may be a = ‘OO,’ ‘A,’ or ‘D.’ In this case, OO is a means of stating that the material is very soft, while A is for soft. On the other hand, D denotes much harder materials.
Let us take a quick look at some of the more common examples:
- Hard Skateboard Wheels = 98A
- Mouse Pad = 20A
- Smartwatch Band = 70A
- Rubber Band = 25A
- Gel Insole = 30OO
- Soft Skateboard Wheels = 78
Check out the best printers for flexible filament
A Few Things That You Can Print With Flexible Filaments
There are plenty of things that you can print with the best flexible filaments via a direct drive TPU 3D printer. Some of them include the following:
- A cable tie to tie up all of your cables
- A custom watch strap to make your new or even old watch really shine
- A shoe sole in case your old sole has fallen apart after a hectic hiking trip
- A new phone case to enhance the décor of your smartphone
- Drone parts and other components for electronic gadgets
How to Print Flexible Filament Successfully
The age-old adage, ‘slow and steady wins the race,’ holds particularly true for the best flex filament around. This is because they typically print best only if you decide to use a really slow and consistent feed rate.
Since the material is very elastic, it may be tough to control the semi-flexible filament flow due to sudden printing speed changes. The higher the speed of your direct drive equipped printer, the more the chances of a jam in the works. Yes, it will take longer, but the result will definitely be worth the effort.
It would help if you were to fine-tune your retraction settings to no retraction while making sure that there is as little gap in the extruder as possible. This will allow printing with semi-flexible material for excellent printed objects. You will also have to tweak your drive extruders too.
Is TPU Toxic?
By and large, we can confidently assert that TPU material is generally non-toxic. Semi-flexible TPU is made by combining different types of polymers and other chemicals. On their own, they may be toxic, but when combined to make TPU, they become inert and non-toxic.
We may now conclude this article by stating that the invention of the best flexible filaments has been a great boon for the 3D printing community. As of now, they can print plenty of useful objects with the help of a dazzling variety of flexible filaments for best print quality even with difficult to print builds.