The Jiga Resource Center

What are Flexible Filaments?

Flexible filaments are plastic materials used to create objects with 3D printers. As you may have guessed, the material is flexible and made from TPEs or thermoplastic elastomers.

So, what exactly is TPE?

TPEs are polymers with properties that blend those of rubber plastic. In other words, it can be stretched and twisted easily while still retaining some rigidity. There are several types of TPEs, and each of their chemical structures varies – that means that some will be more elastic than others!

This allows different manufacturers to experiment with chemical formulas to create filaments as elastic as rubber bands, or as flexible as a tire. 

Note that not all flexible filaments fall into the TPE category. However, these are the most widely used materials so this guide will focus on exploring them in greater detail. 

Let’s review some important features of thermoplastic elastomers:

TPEs are soft and flexible and contain strong electrical properties. They can resist fatigue easily and dampen vibrations, making them ideal materials in the 3D printing space. 

Even though TPEs are elastic and flexible, they still have a high impact strength. Objects made from TPEs can resist weathering, chemicals, abrasion, and more – so you don’t have to worry about your 3D prints degrading quickly. 

Most TPEs can handle temperatures from -30 to 140 °C, which means it is suitable for almost any type of environment! Similarly, the material is recyclable so you can build 3D prints without worrying about damaging the environment. 

TPEs are not a perfect material, though, and do have some drawbacks. For instance, their softness and flexibility can often make it difficult for 3D printer extruders to handle them well. Likewise, they can buckle when passing through the extrude. 

They are also sensitive to rapid movement, which can cause uneven printing surfaces.

Also, the materials absorb moisture because they are hygroscopic. If you do not store your filaments properly, they can end up causing your 3D prints to sizzle and pop up when they are finished. 

Flexible Filament Types

When it comes to flexible filaments that you can use in 3D printing, you have several options to choose from. As we mentioned, the chemical structures in each will be different and that will determine their flexibility and rigidness. 

Here is a guide to the common types of TPEs:

Thermoplastic Polyurethane (TPU)

The most popular flexible filament is TPU or thermoplastic polyurethane. It is strong and highly durable, which means it is a lot more rigid than other options. The benefit of having a rigid filament is that it can pass through the extruder with ease!

There are many applications for TPU in 3D printing. If you have ever purchased a custom phone case, it is likely made from this material! You can also use it to create rubber mats, ski boots, or shoe insoles.

TPU has a unique application in the RC car space since it has the perfect features to create shock absorbers, tires, seals, and even O-rings. Part of the reason it is so effective here is that TPU allows the prototypes to resist the stress from sudden movements and impacts. 

Pros

TPU is a highly elastic flexible filament, with ranges anywhere from 600% to 700%. Its shore hardness falls between 60A and 55D, and it produces excellent quality prints. 

You don’t need to use a heated print bed when using TPU, and the material will not show much shrinkage or warping. There are not any noticeable fumes produced during the printing process, however, this material is not food safe. 

The material is highly resistant to abrasion and can also provide substantial protection from greases and oils.

Cons

Print speeds are a bit slower with TPUs because it can be tough to push the right amount of flexible filament through the hot end. Using a direct drive extruder can significantly improve your 3D printing results, though. 

Getting the right temperature is essential. If it is too hot, you will see strings on your print – if it is too cold, the layer adhesion will suffer. 

Likewise, TPUs do not handle UV light very well. 

Thermoplastic Polyamide (TPA)

Next on our list is TPA, which is a copolymer of flexible nylon and TPE. 

So, what happens when you mix these two materials? You get a flexible filament that has the smooth texture of nylon combined with TPE’s flexibility!

This makes it the perfect material for producing goods like golf balls, medical products, and even ski equipment. 

Pros

One of the benefits of working with TPA is that is highly flexible. It provides ideal layer adhesion and heat resistance, so you can produce details and high-quality prints. 

The elasticity ranges from 370% to 497%, and it has a shore hardness from 75 to 63A. As you can see, it is less elastic and more rigid than TPU, but that makes it exceptionally durable!

Cons

Unfortunately, warping is common for prints made with TPA. You need to store the material in dry places, or else it will begin to absorb moisture. 

Thermoplastic Co-Polyester (TPC)

Another type of flexible filament is TPC, which is made of an alternating sequence of short-chain and long-chain glycols. That means that it contains both soft and hard segments, making it an engineering-grade material. 

In other words, while it is used for various industrial applications, it is not common for hobbyist 3D printers to use this material. 

For example, companies will use TPC to make self-expandable polymer stents and bellows!

Pros

This material has a low density and a Shore hardness range of 40 to 72D. The elasticity can vary from 350% to 530%, and it has good thermal stability. 

Its strength and resistance to high temperatures make it ideal for industrial applications!

Cons

TPC cannot be used for objects that need to be highly flexible, and they have less elongation at break. 

Acrylonitrile Butadiene Styrene (ABS)

You can also choose to work with ABS, which is also part of the thermoplastic polymers group. Its name tells you exactly what it is made of: acrylonitrile, butadiene, and styrene.

ABS is a popular choice for building toys like legos, sports equipment, and low-cost prototypes for various industries. 

Pros

This is a popular choice for at-home 3D printing since it is easy to use but still provides strong properties. For instance, it is lightweight, impact-resistant, and affordable!

ABS also has a low melting point, so you can use it with a smaller printer or for an injection molding process. It is also very safe to operate.

Cons

Even though ABS is great for use at home, it is not the best choice for industrial applications! The melting point is too low, and it does not offer enough strength and durability for those needs.

Polylactic Acid (Soft PLA)

The last flexible filament on our list is polylactic acid or PLA. This thermoplastic is made from renewable sources like sugarcane or cornstarch – not petroleum. PLA is also called soft PLA since it can be very rubbery.

It can absorb impacts and vibrations, so industrial applications include objects that need to bend and give without breaking or losing their shape. Likewise, PLA is food safe and can be used for utensils and food containers. 

The blend of firmness and flexibility also makes this a great choice for pen grips and shoe inserts. 

Pros

This material has a low carbon footprint and is often biodegradable. It combines strength, flexibility, and durability.

Having food-safe capabilities is another benefit since it allows you to create objects that can safely interact with food. 

Cons

If you do not convert it to soft PLA, the material can be very brittle. Similarly, it can have various problems during the 3D printing process like difficulty going through the extruder. 

Popular Flexible Filament Brands

Now that you have a general overview of the flexible filament materials available, let’s review some popular brands you can choose from. 

MatterHackers Pro

MatterHackers has a wide range of flexible filaments to choose from. Their color options are second to none, and they are well known for producing high-quality TPU flexible filament.

This specific material has a shore hardness of 90A, which makes it relatively bendier than other options. MatterHackers even offers a more flexible option with their Pro Series Flex TPE!

You can print from 15 to 30 mm/s with this filament, and the cost is about $45 per spool. 

Cheetah TPU

Cheeta TPU is a filament produced by NinjaTek, a popular name in the industry. This material was built to allow you to print at quicker speeds – hence the name Cheetah – without sacrificing quality and durability. 

It can operate at up to 60 mm/s, which is almost as fast as what you can obtain with ABS! You can print faster with this option because of its shore hardness of 95A. 

The cost of this filament ranges from $55 to $85, and you can choose from several different diameters and sizes: 05. kg or 1 kg, and 1.75 mm or 3 mm. NinjaTek also offers a wide variety of colors, so you can create objects in whichever color you’d like!

Polymakr Polyflex Filament

Another great TPU option is Polyflex Filament by Polymakr. 

The shore hardness rating for this material reaches up to 95A, so it is comparable to the NinjaTek filament we just described. However, they mention that the hardness can vary down to 90A, so humidity and temperature may play a role. 

So, if you need specific hardness requirements, this may not be the best option. Their color choices are limited too, and you can only buy it in 750 g spools. 

FormFutura FlexiFil TPC

This next flexible filament is unique because it is constructed from bio-oils. FlexiFil TPC is like Polyflex and has a range of hardness: 92 to 94A. 

You can purchase this filament in 0.5 kg spools, and the print speeds must be slow for it to work properly. Failure to keep the printer moving between 10 to 20 mm/s can cause the filament to buckle within the intruder. 

If you are not in a rush to finish your prints, though, this is an environmentally friendlier option. 

It is also important to note that some users have commented that their colors do not match what was expected – so consider this if you need specific colors. 

Taulman3D PCTPE

Taulman 3D PCTPE, or plasticized copolyimide TPE, is made from a chemical compound of TPE and Nylon. This material can print easily because it is less elastic and flexible but has the durability of nylon. 

Even though they do not advertise a specific shore hardness level, it is estimated to be above 100A. With that said, this is not the best material for objects that need to flex or bend. If you need something as durable as nylon that is slightly more flexible, though, it will get the job done!

XYZ Flexible Filament

XYZ has developed a proprietary filament designed for both durability and flexibility. It is waterproof and non-toxic, so it has a wide range of applications. 

It comes in a cartridge that is very easy to use, and even includes a chip that lets you know how much material remains in the spool. 

XYZ flexible filament can complement PLA and ABS projects too since they provide shock absorption, durability, and elasticity. 

Recreus Filaflex TPE

Finally, we have Filaflex TPE by Recreus. This flexible filament is a direct competitor to those offered by Ninjaflex.

Out of all the materials on this list, Filaflex is the softest. It has a hardness level of 82A, which is ideal for printing very flexible objects. It is necessary to note that you may need a special extruder and thermal insulator to get the most out of this material!

It boasts an impressive elongation to break of 700%, but you probably don’t need this level of stretch for most applications. This option comes in a wide range of colors, and you can choose from 250g and 500g spools. 

Different Types of Metals, Properties, and Uses

The best place to start is defining the most common types of metal, their properties, and popular uses. Let’s dive in!

Aluminum

Aluminum is a popular metal that has a wide variety of applications. It is the most popular non-ferrous metal. 

It was first developed in 1825 and boasts an impressive strength to weight ratio. This metal is malleable – meaning you can form it with ease – and does not rust. While it isn’t as strong as other options like steel, its durability, lightweight, and ease of machining make it very appealing. 

Similarly, you can cut aluminum into extremely thin sheets, like what we use for foil. 

Even though aluminum doesn’t rust, it can oxidize. That means that it corrodes after prolonged exposure to salt – not water. When this happens, a chalky, white residue will build upon the metal. 

One of the reasons that aluminum is so popular is its versatility. You can use it for everything from soda cans and grilling trays to freshwater boats. Aluminum was even used on the space shuttle that sent a man to the moon!

Stainless Steel

Stainless steel is an alloy of iron, carbon, chromium, and several other metals. It is unique because it does not oxidize or rust, so maintenance is simple. 

This metal is very sturdy and versatile, so you can also use it for furniture and fixtures. That’s why so many people opt for stainless steel appliances! Even most utensils are made out of this material. 

Brass

Brass is a copper and zinc alloy. The ratio of each of these metals will vary depending on the properties you are looking for. In some cases, it can include some small amounts of lead and aluminum too. 

This metal comes in many different colors, like bronze, gold, yellow, red, and brown. It is resistant to corrosion and antimicrobial, so people tend to use this for faucets and door knobs. Note that if you use harsh chemicals on it, the finish can crack, though. 

You can tell the difference between brass and goals by hitting it – if it vibrates like a bell, you’ve got brass!

Other valuable applications of brass include plumbing, locks, bearings, and even musical instruments. Likewise, you can use it in flammable environments since it is intrinsically safe. 

Copper

Copper is an alloy with a long history as a conductor. It is perfect for circuits since it has the best heat and electrical conductivity capabilities next to silver. 

This metal does not occur naturally, so it must be smelted and extracted from the ore. It has a reddish-orange color, but as it oxidizes, it can become blue or green. Copper is easy to form too, so you can also find it in tools like cooking utensils. 

Bronze

Another copper alloy on our list is bronze. It contains tin, and manufacturers will often incorporate silicon, phosphorus, and aluminum to improve its properties for specific applications. Bronze has thermal and electrical conductivity properties and is also resistant to corrosion. 

This metal is also hard, brittle, and can handle fatigue well. As a result, it can make electrical connectors, ship fittings, reflectors, and more. 

Titanium

Titanium is one of the most popular metals used for engineering since it is both lightweight and strong. It is one of the most abundant metals on earth, but refining it is difficult – that’s why it is so expensive!

This metal has the highest strength to weight ratio and strong resistance to corrosion, which is why it is ideal for airplanes and anything else that flies. Another unique property of titanium is that your body will not reject it, so it is the material of choice when manufacturing medical implants. 

It also has high thermal stability, so you can also find it in military equipment and chemicals. 

What Types of Metals Are Magnetic?

So, which of these metals are magnetic? Before we answer that question, it is necessary to review how magnets work.

Atoms contain electrons that move around, and this motion creates a small magnetic field. The motion of other electrons normally cancels it out since it generates an opposing magnetic field. However, when the magnetic fields spin in alignment, it creates a net field over the entire object. 

In other words, rather than canceling each other out, these magnetic fields amplify each other. Magnets will have north (positive) and south (negative) poles – opposites attract one another, and matching poles repel. 

Ferrous Metals

When a metal has iron in it, it is called a ferrous metal. This is what gives it magnetic properties! If metal does not have any iron mixed in, it is considered non-ferrous and will not be magnetic. 

Metals like iron, nickel, and cobalt are all magnetic. Stainless steel also falls into this category.

Paramagnetic Metals

Similarly, metals can also be paramagnetic. These materials have a weaker attraction to magnets so they won’t retain their magnetic properties outside of a magnetic field. Some examples include the following:

• Aluminum
• Lithium
• Platinum
• Magnesium
• Tungsten

Diamagnetic Metals

What about metals that repel magnets? These are called diamagnetic metals. 

With these materials, their electron fields work against the magnet instead of enhancing it. That is why they repel them.

Lead, copper, mercury, and silver are all diamagnetic metals. 

Permanent Magnets

When you think of magnets, you are likely thinking of permanent ones. Think of a refrigerator magnet – it sticks on the door no matter what, right?

Iron is the most common type of permanent magnet. Others are made from ferrite, which is a compound made from iron oxide and other metallic elements. 

They can also consist of alnico alloy – a mixture of aluminum, cobalt, and nickel. Alnico alloy is popular for consumer and industrial electronics since they make strong permanent magnets. 

Electromagnets

Electromagnets are an additional type of magnet. These are made from an iron, cobalt, or nickel core that has a coil of copper wrapped around it. The wire creates a magnetic field any time electric currents move through it, but the fields disappear when it stops. 

That means all electromagnets need electricity to work, but the benefit is that you can control the power of the magnetic field by adjusting the strength of the current. These magnets are used in traffic lights, switches in relays, and even junkyard cranes. 

More advanced applications of electromagnets include MRI machines and particle accelerators. 

Types of Metal 3D Printing

3D printers can use metal powder to create objects, parts, and more. The unique properties of the metal will determine how the 3D printers fuse it, and the process will vary based on the materials used. 

Here are the various ways you can use metal in 3D printing: 

Powder Bed Fusion

Powder bed fusion is the most popular type of metal 3D printing. It is also called powder bed melting since it involves selectively melting a cross-section of metal powder.

The 3D printer will spread out a thin layer of powder on the build plate, then melt part of it to create your object. 

There are two ways to accomplish this process: selective laser melting or electron beam melting. 

Selective Laser Melting

As we mentioned, powder bed fusion is the most common way to 3D print with metal. Of the two options available, selective laser melting, or SLM, is most frequently used. This process is sometimes called laser powder bed fusion or selective laser sintering, but the concept is the same.

These machines use high-powered lasers to fuse layers of metal into your final part. Once the print is done, you can remove it from the powder bed and begin cutting parts off the build plate. You will also need to post-process the object. 

SLM is very effective for creating complex parts that require precision and have geometrical challenges. For example, there are many applications in the aerospace and healthcare industries. As a result, the build volumes can range drastically. 

You can determine the precision of the machine based on the layer height and width of the laser beam. The print speed on SLM printers is moderate, so you can’t expect it to produce a large number of objects in a short timeframe.

A drawback to this option is that the post-processing requirements can be extensive. Most machines require professional operators since the process is intricate, and you will probably need to tweak the designs several times to make it work. 

There are also some safety risks since SLM 3D printers use metal powder that can be dangerous – and expensive – to handle properly. 

Direct Energy Deposition

A different way to 3D print metal is through direct energy deposition or DED. This type of printing works by using a laser and metal feedstock to make parts. The stock can either be powder or wire, and it sits with the laser on a single print head.

How is that different than SLM?

The key is that the print head dispenses and fuses the metal at the same time. Rather than spreading the powder throughout the print bed and using a laser to melt it, DED printers blow the metal material out and fuse it to the part simultaneously. 

Another thing that makes this machine unique is that you can use it to correct imperfections on parts not printed by the machine. 

However, the types of metals you can use – and the cost of the equipment – fall directly in line with those for selective laser melting printers. 

Bound Powder Extrusion

This type of 3D printing can work with metal and is also called atomic diffusion additive manufacturing. 

This technology is much newer than the ones we just discussed, and they are different because these machines don’t rely on loose metal powder. Instead, the material is bound with waxy polymers in a way that mimics the process for metal injection molding. 

Unlike the loose powder that can be dangerous and poses a health risk, the bonded metal material can be handled safely without protective measures. Not only is the material safer, but it can also be easily extruded from a nozzle like traditional 3D printing materials.

That means that the building process is very similar to conventional plastic printing. It is effective for almost all types of geometric parts and can even create objects with an open cell infill. 

After the object has been printed, you must complete two post-processing steps. The first involves a washing machine that will dissolve most of the waxy polymer – leaving behind the fused metal powder. Next, you must place the object in an oven to be sintered, where it will shrink down and yield your completed metal part.

Some models like the Metal X printing system include the 3D printer, wash station, and sintering furnace together. They are much more affordable than SLM and DED machines, with a price range of $120,000 to $200,000.

Binder Jetting

The last type of metal 3D printing technique we will review is binder jetting. This is a large-scale, high fidelity process, and many in the industry believe that it will eventually replace SLM printers as the first choice for powder-based metal printing. 

It boasts speed and scalability, and the goal of the manufacturers is to improve metal additive manufacturing capabilities to production volumes. 

The technology is like an inkjet printer: the machine distributes an even coating of metal powder over the print bed to create an unbound layer. The jetting head will then distribute a binding polymer in the shape of the part, which loosely adheres to the part. 

This process will repeat itself until you have a completed part!

Binder jetting machines have high levels of precision and can create pieces with fine detail. While the speed is an advantage, the cost is much higher than other options.

Types of Metal CNC Machining

CNC machining, or computer numerical control machining, is the process of machining a piece of metal with a computer. The tool uses the coded and programmed instructions to control the cutting or grinding tools, so a manual operator is not necessary. 

There are various ways to accomplish CNC machining in metal, including milling, solid sink EDM, wire EDM, and surface grinding. 

Milling

Milling is a popular option when it comes to machining various metals. These machines hold the object in place, and the milling tool will rotate on a spindle to cut it. The spindle can use interchangeable cutting tools that move across all axes: X, Y, and Z.

This process is ideal for removing stock from asymmetrical or complicated pieces. They can also drill bores and holes, create notches and channels, and cut precise angles. 

As you can imagine, the mill can heat up quickly as it rubs against the metal. You will need cutting fluid to keep the object cool, and lubrication to eliminate any metal particles. 

Solid Sink EDM

Another option for CNC machining in metal is a solid sink EDM. With this method, you put a conductive electrode that is bathed in a dielectric fluid near the piece you are working on. The electrode will discharge, and this process forces metal particles away from the object.

Note that the electrode doesn’t touch the metal you are machining but rather is a sacrificial tool. As a result, you will likely need to replace it frequently. 

You can use the solid sink EDM process to make holes, pockets, and other features within steel tools and other hard metals that are difficult to work with. Similarly, EDM can be used for plastic injection molds, recessed (or debossed) lettering, and other textured surfaces. 

Wire EDM

If you need to make circular and smooth features on a metal object, consider using wire EDM. This option relies on a conductor made of copper wire to create a high-voltage electric charge. 

The machine feeds the wire from a spool since the conductor will erode during the cutting process. A necessary thing to note about wire EDM is that you can’t use it in a blind hole because it needs a pass-through.

Wire EDM is most often used on hardened or thick tool steel to create circular or semi-circular features that you could not create with other conventional cutting tools. 

Surface Grinding

Surface grinding is the best option for making extremely flat surfaces. It uses a precision grinder in the form of a spinning disk.

Depending on your needs, you can swap out the disk to adjust the coarseness or abrasive grit of the piece. Once you select the appropriate grinder, you will need to mount the metal on the table and move it back and forth under the grinder. 

Expertise is required to use surface grinding tools on metal since mechanical stress and high heat can damage the object. In other words, you must carefully control the temperature and speed of the tool to get the right results. 

Creality — 3D Printing Evangelist

Creality is a 3D printer manufacturer based in China. The company was founded in 2014, and have since brought some of the best consumer 3D printers to market. Creality manufactures both filament and resin printers, and researches and develops FDM (Fused Deposition Modeling) and resin technologies. Creality has also produced 3D scanners and operates both within the consumer and industrial areas of additive printing. The company has garnered the trust and admiration of a worldwide consumer base, and they export to over 100 different countries. All Creality products are CE, FCC, and ROHS certified. When Creality releases something, it’s worth it for you to get excited.

Creality’s most notable collection of 3D printers is the CR series. This series carries the company’s trademark style, reliability, and, of course, its high quality. Whether you’re a business professional or hobbyist, Creality is going to have that special something for you. And that special something could very well be the new CR-10 Smart.