PET Recycling – From Bottle to Filament

Recycling. A word often related to large companies receiving tons and tons of paper or plastic in an effort to reduce our carbon footprint. However if we look at plastic bottles for instance, humans buy a million plastic bottles per minute, and 91% of all plastic is not recycled. This article is going to cover what makes plastic recycling so important, how to recycle PET and the future of recycling in 3D printing.

What is PET Recycling?

Focusing on plastic bottles here, they have one huge advantage – unlimited recycling potential. PET is one of the few polymers that can be recycled into the same form over and over again. Think of it as a closed-loop recycling solution.

PET recycling loop
The “closed-loop” of PET recycling. Image via PETCO

Recycled PET, or rPET, can be used to make many new products. This can range from clothing, automotive parts, packaging as well as bottles for food/non-food products. Depending on the application required, rPET will be blended with the original PET.

What Are The Uses of Recycled PET (rPET)?

As mentioned above, rPET has many great uses, which includes:

  • Food containers
  • Polyester carpet fiber
  • Fabric for T-shirts
  • Athletic shoes
  • Luggage and upholstery
  • Sweaters and fiberfill for sleeping bags and winter coats
  • Industrial strapping
  • Sheet and film
  • Automotive parts
  • New PET containers
Some recycled PET products

Using rPET in place of the normal or virgin PET has substantial environmental impacts as well as reducing overall energy consumption.

Creating Our Own Filament from Plastic Bottles

Now that we’ve covered the background of recycling PET, how exactly does one go about doing the actual recycling? The one method is simply going to your local recycling company and dumping your plastic waste there, or having it picked up at home if that company provides a pick-up functionality. The other method though is a bit more rewarding – doing it yourself.

We wanted to test of normal plastic bottles can be turned into 3D printing filament. The following is a quick summary of our tests to turn around 30 bottles into filament.

  • Water bottles were collected, cleaned (properly) and any external caps or seals were also removed
  • The bottles were then vacuum sealed and heated to reduce their size
  • Once cooled the bottles were cut into smaller chunks with a saw and a pair of scissors
  • After that, the pieces were shredded into tiny pieces using our SHR3D IT
  • The pieces were then dried at a temperature of 160°C for 4 hours
  • The PET was then fed into our Next filament extruder
  • After multiple tests at different nozzle diameters and temperatures, our team ended up with a great result of PET filament
PET Filament Final Result
Final results of the filament

If you’d like to read the complete test and the different results, you can find the document here.

The Future of Plastic Recycling in 3D Printing

The biggest issue that faces 3D printing recycled filament – dirt. With the above experiment, just cleaning those bottles took a great deal of effort. Now imagine doing it with tons of plastic, often coming from dumps that have been contaminated all forms of impurities.

Also, one has to take note that different types of plastic produce different types of filament. High-density polyethylene — shampoo bottles, for example — are relatively easy to convert into filament, but it’s difficult to print with because it shrinks more than other plastics as it cools. On the other hand, PET, prints well but is brittle, making it difficult to spool as filament.

Recently, we saw the US Department of Defense (DoD) is exploring 3D printing feedstock made from plastic containers that have been left on the battlefield, which can hopefully be reproduced in other government sectors. There’s also Ethical Filament, a company focused on promoting the concept of recycling to produce ethical 3D printing filament that is sold to improve the livelihoods of waste pickers and their communities worldwide. Then there’s the Perpetual Plastic Project (PPP), which is an installation which can directly recycle old plastic drinking cups into 3D printing gadgets as well as other plastic products if needed.

While there is more and more aware of using recycled filament for 3D printing, we still have a long way to go. Hopefully, with the rise in 3D printing over the last few years, more emphasis is being placed on plastic recycling.

 

Bio PE – Extruding the Renewable Polymer

Last year saw a huge surge in the varieties of different 3D printing materials. However, with the world’s focus on saving the environment, not many are coming from biological sources. Even though 3D prints can be recycled into other 3D prints, it is not a zero-sum outcome. With the increase in biological materials though, the end result would be just carbon dioxide and water. In this article we focus on one of these biological materials – Bio PE – and if it can be extruded using our Next filament extruder.

Bio PE Summary

By definition, bio-plastics and biopolymers are the type of plastics and polymers which come from renewable biomass sources. These sources include: vegetable oils, sugarcane, starch and wheat grain. Depending on the products; the global bio-plastics market includes bio-PET, starch blends, PLA, bio-PA, bio-PE and others. Bio PE, or biopolyethylene, is simply polyethylene made out of ethanol. After a dehydration process, it becomes ethylene using these biomass sources. The final product is polyethylene, which properties mimic those of conventional polyethylene.

Applications

The main application for biopolymers is packaging, which makes up around 28% of the total volume shown in 2016. This includes shopping bags, food packaging, bottles and many other uses. Other uses include blow-molded hollow parts such as automotive fuel tanks, injection molded parts, tubes and other applications used in the automotive and consumer-goods industries.

Advantages & Disadvantages

sugarcane field

According to Braskem, the world-leading supplier of bio-PE, a production rate of 200 kilo ton/year of bio-PE would require approximately 450 million liters of ethanol. This would utilize 65 million hectares of Brazilian sugar cane land to produce enough sugar to enable Braskem’s production capacity. This represents 0.02% of the Brazilian arable land.  Clearly, the impact to the sugar cane food supply is quite small.

Another great advantage is that the chemical structure, applications, and recycling are identical to fossil-fuel based PE. Also do not forget that Bio PE is 100% recyclable.

All these advantages do come with one main drawback. Currently, the price of bio-PE is about 50% higher than fossil-fuel PE. In upcoming years though it should see a decrease in price when volumes increase.

Extruding Bio PE + TMP + MAPE

Here at 3devo we were able to acquire some Bio Polyethylene (PE) SHD 7255 LSL, including 20% thermomechanical pulp (TMP) and 6% maleated polyethylene (MAPE). Take note this is just a short summary of our testing. More information can be found here.

Preparation and Extrusion

Cleaning the Next filament extruder has been very important. Either a purging compound or HDPE can be used. Drying the materials was also critical. After 7 hours of drying the material doubled in moisture content over 48 hours (stored in a closed container with silica gel), it was finally ready. Three tests were conducted, using various temperatures and settings. It was interesting to see how quickly the material heated up, and fast fan cooling was vital it to handle more stress. Low temperatures also helped improve the results.

The end result of the extrusion tests

Extrusion Summary

After multiple tests, we conclude that Bio PE + TMP + MAPE combination can be successfully extruded with the Next. Some issues include the TMP particles causing the material to get easily torn apart and the ease at which the material heats up. Cleaning also determines the best results for the final filament.

Conclusion

In the end, bio-plastics and biopolymers are definitely something to focus on in the future of 3D printing. Their unique characteristics make it great for sustainable development. Also now that extruding materials like this is possible, it will be great to see what upcoming projects will be rolling out in the years ahead.

PEI – Extruding The High-Performance Polymer

PEI, Polyetherimide, is one of the more rare polymers we have tested here at 3devo. That, however, does not mean it is any less useful. This high performance engineering thermoplastic, usually with an amber to transparent colour, makes a great name for itself in various high-demanding applications. It can often replace metal or other strong substances thanks to its impressive chemical and mechanical properties, but how well does it extrude? In this article we will make a brief overview of PEI as well as our extrusion tests for this strong polymer.

Filament Summary

PEI’s characteristics include extreme rigidity, high strength (even at elevated temperatures), long term heat resistance, dimensional stability and good electrical properties. It is easy to spot due to its light amber colour (unfilled) and is usually semi-transparent. Like other amorphous, high temperature resins, PEI has outstanding dimensional stability and is inherently flame retardant.

PEI does resist chemicals, such as hydrocarbons, alcohols and halogenated solvents. Creep resistance over the long term allows PEI to replace metal and other materials in many structural applications. It is also widely used in electronics because of its good arc resistance and dielectric constant. Furhermore, PEI is UFDA/USDA and USP class VI compliant.

Applications

PEI used in vape mouthpieces (left) to plastic manifolds (right) via Carville Plastics
  • Reusable machined components
  • Aircraft/Automotive instrumentation
  • Plastic Manifolds
  • Electrical insulators
  • Electrical component housings

Advantages

  • Great thermal stability (continuous use temperature of 365F/180° C)
  • High strength
  • Continuous rigidity and strength to 340F (170°C)
  • Dimensionally stable
  • Excellent flame and heat resistance (UL 94 V-0 rated)
  • Consistent dielectric properties over a range of frequencies
  • Good acid resistance
  • High resistance to autoclave sanitizing
  • Low moisture absorption
  • Can withstand steam autoclaving
  • Inherently flame retardant
  • Certified Grades for food-contact and bio-compatibility applications

Disadvantages

  • Can be expensive
  • Not a lot of colour choices (amber or sometimes transparent)

Extruding PEI (ULTEM 1010 Resin)

Here at 3devo we were able to acquire some PEI for extrusion tests (Ultem 1010 Resin was used). Because of its high strength factors we were interested to see what the results would be. Below is an overview of the whole process, however, for a more detailed report please contact us via the sales contact page.

Preparation

PEI resin (left) and adding it into the hopper (right)

First cleaning of the NEXT extruder had to take place.  Using ASACLEAN™ GL2 followed by ASACLEAN™ PX2, we were able to clean the device to prevent any impurities impacting the results. Once both materials had run through the device in order to properly clean it, the heaters were all set to the same temperature (160 °C). 

Observation Indicators

There are three important things to look out for when extruding new filament for the first time:

  • How does the filament look? Are there any signs of bubbles/holes, die lines, weld
    lines, melt fracture or warpage?
  • Is the flow similar to that of standard PLA (when using the same rpm)?
  • Is it possible to pull the material without any trouble (the material does not stick to
    the puller wheel and does not break as a result of the force of the puller)?

Extrusion Summary

Extruding PEI (left) and the results (right)

After multiple tests, we concluded that PEI is able to be successfully extruded with the NEXT. The tests we ran determined that PEI should be extruded below 370 °C (but not too low) in order to prevent bubbles and holes from forming, and that proper cleaning methods should be used in order to determine the best results.

Conclusion

In the end, PEI was a very interesting polymer to test out compared to other ones we have tested in the past. Its high strength, rigidity and thermal stability meant that a lot of care had to be taken when running the tests. PEI though is a great filament and very useful, especially in aerospace and automotive applications.

Zortrax Filament – Extruding the Filament and its Benefits

Zortrax is a name renowned for precision engineering. Most famous for their exclusive line of 3D printers, namely the M300 and M200, creating high quality prints with ease. However, Zortrax also shine in their range of filaments. These all boast great qualities and are ideal for a range of uses from prototypes to decorative elements.

range-zortrax
Zortrax range of 3D printers (photo via Zortrax).

We soon decided to focus on one of their more popular filaments: Z-ULTRAT. Therefore, we wanted to see how well it would extrude, and what use it could be for you or your business.

Filament Summary

Z-ULTRAT filament (photo via Zortrax).

The Z-ULTRAT is no ordinary filament, designed purely for its own Zortrax M200 3D Printer. Its main features (high hardness and durability) make it great for prototyping mechanical parts, architectural models and design prototypes. Below are its key features:

Name Z-ULTRAT 3D Printing Filament Cool Grey 1.75mm 800g
Filament Material ABS
Printing technology LPD (Layer Plastic Deposition)
Dedicated device Zortrax M200 3D Printer
Features
  • Durable and strong
  • High hardness level
  • Low elasticity
  • Low level of deformation
Weight 1 kg (2.2 lb) gross wt. / 800 g (1.76 lb) net. wt.
Efficient melting point for 3D printing 269 – 279 °C [516 – 534 F]
Glass Transition Temperature 144 °C [291 F]
Vicat Softening Temperature 130 °C [266 F]

 

Thermal Expansion Minimal
Odor Nearly odorless
Hazards Product does not present any hazard while operating

For more information see the official Zortrax Material Data Sheet.

While these are all good features, it is not so easy for extrusion. Especially when comparing it to PLA. The next step will look at testing how well the filament extrudes using our NEXT filament extruder.

Extruding Z-ULTRAT 3D Printing Filament

failed-prints
Failed prints used for testing.

Pre-Conditions

The Regular NEXT 1.0 was used for the tests, and was set to 220 °C across all three sections. The purpose for using the regular extruder as opposed to the Advanced version, is due to the extrusion screw of the model. It has been previously observed that the Regular screw, lacking the pineapple mixing station, is generating more pressure. Better nozzle flow is a result of this.

The machine is pre-loaded with HDPE. This is to ensure the extrusion barrel and screw are clean and performing at an optimum level upon receiving the Zortrax ABS. In order to remove all contaminants, the machine was left to run HDPE for an hour. The filament was added after this step.

Results

Numerous tests were completed using different settings in order to achieve industry-standard results. Below is a graph showing off the stability over time:

filament-thickness
Filament thickness results over time after extrusion.

In the end, the filament became stable at: 1- 275 / 2- 280 / 3 – 270 at speeds of 5rpm.

before-and-after
Left to right: shredded filament into the extruder, final result of the Z-ULTRAT

The filament produced better results after changing the speed to 5rpm, with only slight deviations (still within 100 microns) over 35-40 minutes. As a result, the test was a success. This was because a thickness of 1.75mm is not easy to extrude, as more control is needed. Also noted that ABS is harder to extrude when compared to other filaments such as PLA.

Conclusion

robotic-arm
Zortrax Robotic Arm printed using the M200.

The Zortrax range of 3D printers and filaments offer fantastic end results. Mechanical parts, casing elements for testing and even consumer/educational product prototypes – all are possible, with complimentary colours to go with. Furthermore, you have the option of recycling your prints after you are done. This means both businesses and printing enthusiasts alike will be able to take full advantage of these great products.

Testing PAEK – Is It Any Good?

Here at 3Devo, we really enjoying testing a variety of different filaments. Last week we were about to test some PAEK. As you may or may not know, PAEK is a family of semi-crystalline thermoplastics with high-temperature stability and high mechanical strength. We were lucky enough to test some AvaSpire AV-621 from Solvay (provided by ALBIS PLASTIQUE France). Catchy name, but is it any good? This article will cover all you need to know about PAEK, and how it performed in our tests.
_

General Information

 

Image 3devo – PAEK material provided by ALBIS Plastique France

As mentioned PAEK, or polyaryletherketone, is a family of semi-crystalline thermoplastics. In this family you will find:

  • Polyetherketone (PEK)
  • Polyetheretherketone (PEEK)
  • Polyetherketoneketone (PEKK)
  • Polyetheretherketoneketone (PEEKK)
  • Polyetherketoneetherketoneketone (PEKEKK)

Polyaryletherketone (PAEK) was first prepared in the early 1970s, but results and the overall process was somewhat limited. PEEK was the first thermoplastic to go large scale in 1977, where ICI used polyetherification reactions to create the polymer. In 1981, Victrex of Lancashire, England, introduced PEEK resins commercially. Next came PEK, introduced by BASF AG, the large German plastics company, which attempted to gain the total market share, eventually stopping all production of PEKEKK resins. This left Victrex as the only supplier of PEK resins in the world.

In the end, PEEK’s growth rates started to soar, mainly due to its high mechanical strength and chemical resistance. From vehicles, to aircrafts, to most electronics and medical applications, more and more suppliers started to enter the market. These suppliers include:

Below is a list of some of the advantages and disadvantages of using PAEK:

Advantages

  • Highly fire-resistant
  • Good chemical resistance
  • Can be used for high temperature applications
  • Excellent mechanical and dielectric properties

Disadvantages

  • Relatively high cost material
  • Anisotropic
  • High temperature molding and extrusion required

 

Tests

In our first attempt to create PAEK filament we used the AV-621 NT grade produced by AvaSpire with a melting point of 340°C, which we pre-dried at 150°C for 4 hours. The first step in the extrusion process was using PX2 cleaning purge (with a temperature range of 280-420°C) as a transition material, in order to be able to raise the temperature of all heaters to 380°C.

paek-test-1
Filling up the NEXT TEST Advanced Extruder, then running the test

The first thing we noticed while extruding with an overall temperature of 380°C, was the large amount of air bubbles in the filament. This could mean two things, either the granulate was not dry enough, or the overall temperature is too high. Lowering the overall temperature by 10°C improved the quality a lot, but now we faced nozzle lip buildup as you can see in the picture below:

paek-test-3
Nozzle lip buildup

Some polymers tend to have this problem, and it causes major surface roughness of the filament. In this case, the buildup was reduced by increasing the temperature of the front heater.

paek-test-4
A little rough around the edges

In the end we managed to create a spool of PAEK with a filament thickness of 1.75mm, but the surface of the filament was still on the rough side. This means we will keep on looking for better settings of the Next Advanced Extruder, but at least the machine has now proved its ability to create PAEK filament. This adds up in the list of successfully tested high-end polymers, along with materials such as PEEK and PEKK.

All You Need to Know About PEKK

Here at 3Devo we really enjoy trying out new polymers. Most of them have different functions and qualities that make them unique. This week we had a look at PEKK, or Polyetherketoneketone. This semicrystalline polymer, shows off both a sound structural performance in high temperature and a strong chemical resistance. These positive qualities make it very useful in various fields, from medicine to aerospace.

Before 2011, PEKK’s main use was for the production of thermoplastic composites. It was sold in limited quantities to a few small compounding companies. These companies offered PEKK in various melting processes, as well as other specialty and composite processes. However, in 2011, Arkema began industrial PEKK production making it more accessible, so let us take a closer look into what makes this polymer so unique.

Overview

PEKK, the multi-use polymer (image via ptonline)
  • PEKK is a part of the High Performance of Polyaryletherketone (PAEK) polymer family.
  • Glass transition temperature of 162°C (323.6°F)
  • The melting temperature for the PEKK homo-polymer is around 400°C
  • Slow crystallization rate
  • Manufacturers and distributors: ArkemaVeloxRTP and Cytec
  • Brand names: Kepstan and RTP

PEEK vs PEKK

Unlike PEEK, PEKK displays both amorphous and crystalline material properties. This makes PEKK quite interesting. Thanks to its unique mechanical, physical and chemical properties, PEKK lends itself to a broader range of uses than PEEK:

  • Up to 80% greater compression strength than PEEK
  • Wider processing window of parameters than PEEK

Unique Qualities

  • High strength and toughness
  • Chemical resistance
  • Easy processing
  • Lower moulded-in stresses
  • Greater dimensional stability
  • Remains transparent even at higher operating temperatures
  • Improved flow characteristics (due to an extremely slow rate of crystallisation)

According to Tim Spahr of Arkema’s Corporate Research in North America, “These properties allow for lower processing temperatures and the ability to process the Kepstan® 6000 Series (one of their products) copolymers polymers as either amorphous or semi-crystalline structures, depending on processing technologies and cooling conditions.” He also added, “They can be injection molded and extruded as an amorphous polymer without the need for quenching.”

Real-world Applications

Medical

A patient-specific OsteoFab cranial implant 3D-printed by OPM. (Image courtesy of OPM.)

Oxford Performance Materials, always popular with their advances in developing of applications, are now using PEKK to improve infections related to artificial hips, knees, and other implanted devices. In February 2014, OPM became the first company to receive FDA clearance. This was for the manufacturing of patient-specific 3D printed polymeric implants for a line of cranial prosthesis as shown above.

Aerospace

The 3D manufactured part — a black bracket holding the instrument’s fiber-optic cables (Image courtesy of NASA)

NASA is also not wanting to be left out of the 3D-printing world. They of course have many projects that involve 3D printing, but last year a 3D printed part received a lot of attention as part of their latest ICESat-2 project. The project aims to examine and measure changes in ice-sheet elevations, sea-ice thicknesses, and global vegetation in Greenland and the Antarctic. Stratasys had to develop a bracket for this project for the sole purpose of space travel. PEKK made its debut in space as part of the satellite, allowing for this central bracket component to be only the second 3D printed part to go into space so far.

Military

Military uses can be plentiful thanks to its robust structure (image via 3dprint.com)

The military will also be using PEKK’s heat and chemical resistance and its ability to withstand heavy mechanical weights for various uses out in the field. For example, a plastic guard that prevents light emitted from a flashlight from exposing a soldier’s location.

Our Tests with PEKK

We decided to use a bag of the Kepstan® 6000 series copolymers, as it offers offer a low melting point and has a slow crystallization rate. We used the Kepstan 6001 PF variant.

Kepstan 6001 PF powder

Like PEEK, the transition material played a key role throughout the PEKK extrusion process.

Extruding the filament on the Advanced Level Extruder

This time we used a different high temperature purging compound: Asaclean PX2 grade (280 Celcius up to 420 Celcius), to reach the desired temperature range for PEKK (330 Celcius up to 345 Celcius).

The finished result!

By pressure feeding the PEKK powder in the hopper of the Advanced Level Extruder, the cooling fans at 30% and the screw speed at 7RPM, we had a good time with the unique filament. Successfully we extruded 2.85mm, which will be tested any time soon by one of our clients. PEKK offers a lot of advantages to say PEEK or other polymers, but it truly stands out in real-world applications. Hopefully more industry sectors can see the potential of this useful polymer.

Polystyrene – The Multi-Purpose 3D-Printing Filament

What is Polystyrene?

First of all, polystyrene (PS) is a thermoplastic. General-purpose polystyrene is clear, hard, and rather brittle. It comes in two forms: a rigid foam material and a typical solid plastic (i.e foam or solid). First discovered in 1839 by Eduard Simon, an apothecary from Berlin, it was dubbed styrol. It then evolved over years. After about 80 years later, macromolecules were discovered when styrol was heated via a chain reaction thanks to German organic chemist Hermann Staudinger. Eventually, this led to the substance receiving its present name, polystyrene.

Dow Chemical Company then invented a proprietary process to make their trademarked and well-known PS foam product “styrofoam” in 1941. Throughout the years, though, the thermoplastic has not been the most favourable in environmental organisations (due to its slow degrading process). It is not hard to deny this fact too, as almost anyone can walk outside and see some form of polystyrene trash on the ground.

Discarded polystyrene cup, one of the more unpopular uses of the material

To make polystyrene, distillation of hydrocarbon fuels is need to create lighter groups called “fractions”. Some of which are combined with other catalysts to produce plastics.  As a result, the polymerization process creates the PS we all know today. However, it does come in many forms. Much like other plastics, such as PETG and TPU, it also has a whole range of uses.

Commons Types and Uses

Many people first think of the soft objects polystyrene is used for (such as cups or packaging), but it is actually seen in many other forms:

Sheet or molded polystyrene

CD Case made from polystyrene

Objects here are usually created using thermoforming (vacuum forming) or injection molding:

  • Disposable plastic cutlery and dinnerware
  • CD cases
  • Smoke detector housing
  • License plate frames
  • Petri dishes
  • Test tubes

Foams

The foam type is great for packaging.

Polystyrene foams are good thermal insulators and are therefore often used as:

  • Building insulation materials
  • Ornamental pillars
  • Packaging

Expanded polystyrene (EPS)

How would be ship electronics without it?

Expanded polystyrene (EPS) is a rigid and tough, closed-cell foam. It is usually white and made of pre-expanded beads, therefore it makes sense to see it in objects like:

  • Trays, plates and bowls
  • Fish boxes

Extruded polystyrene foam

Extruded polystyrene foam (XPS) consists of closed cells, and is most commonly seen in crafts and model building.

 

Common Characteristics

Generally Polystyrene (PS) is an amorphous, glassy polymer that is generally rigid and relatively inexpensive. Unfilled polystyrene has a sparkle appearance and is often referred to as crystal PS or general purpose polystyrene (GPPS). High impact polystyrene grades (HIPS) is produced by adding rubber or butadiene copolymer. Therefore, this increases the toughness and impact strength of the polymer. Other qualities include:

  • High surface qualities
  • Generally non-toxic and odorless
  • Good electric insulator
  • Flammable
  • Shock-resistance
  • Good pressing results
  • Ideal for thermoforming
  • Polished or mat surface
  • Approved for food-contact (although some studies have reported “potential health impacts from polystyrene foam food packaging associated with its production)

 

Advantages and Disadvantages

Pros

  • Inexpensive
  • Readily available
  • White in colour
  • Easy to sand, glue, cut and paint

Cons

  • Flammable, but retarded grades available
  • Inert (i.e. doesn’t react particularly well with either acidic or basic solutions)
  • Poor solvent resistance, attacked by many chemicals
  • Homopolymers are brittle
  • Subject to stress and environmental cracking
  • Poor thermal stability

 

Extruding and 3D Printing

We over at 3devo decided to try out extruding some polystyrene thanks to the NEXT 1.0 filament extruder.

 

Top Left: PS granules used. Top Right: The PS granules in the hopper. Bottom Left: PS filament being extruded with the NEXT 1.0. Bottom Right: The finished filament!

You can email sales@3devo.com for more information about this testing. As a result, the completed filament was a great success, very easy to extrude thanks to the aircooling (via the fans) to keep it from overheating. Below is a short video of the whole process:

But what about 3D printing using PS? Well, High Impact Polystyrene (HIPS) is great for this. This is s a tough durable material, similar to the popular ABS. While it may not be the cheapest option, it does use Limonene as a solvent. The result is a slightly lemon-like smell to the finished product. The heater element of your 3D printer needs to be controlled quite finely with this material otherwise there will be a fair degree of warping as the hot material is placed on the cooling layer. But, you should be good with printing smaller parts though, as the speed of printing should be just fine to prevent warping.

3D Printing with HIPS (via Vexmatech)

In the end, polystyrene is a very interesting thermoplastic. With quite a range of characteristics and uses, it’s easy to see why it has become so popular. And, although it’s so similar to say ABS, its positive qualities such as its good impact resistance and ease of finishing make it a strong contender against the other plastics out there.

 

 

TPU – The 3D-Printing Polymer With An Added Twist

Since 1937, this robust polymer has been making waves among the polymer communities. With its incredible durability, toughness and ease of processing, TPU has the advantages of rubber and plastic. This article will explain why this best-of-both worlds polymer is so useful.

What is TPU?

TPU in its granular form.

TPU, also known as Thermoplastic polyurethane, has been around even before World War II. However, its uses range from sporting goods to medical devices, from phone covers to Aerospace Surface Protection. To create this polymer in a lab, simply create a polyaddition reaction between a diisocyanate and one or more diols, well maybe not too simple, but after that a unique category of plastic emerges.

Uses of TPU

It is used in many sporting goods, including Air Jordans.

Below are some popular uses of TPU:

  • Sportswear (shoes)
  • Wire and cable coating
  • Hydraulic seals and hoses
  • Inflatable rafts
  • Phone cases
  • Medical tubing

As you can see, TPU is mainly used where flexibility plays a key role. However, it is not just flexible. Below are some other advantages of this filament.

Advantages of the Flexible Filament

TPU has many popular qualities making it great for a range of uses

You can think of TPU as a hybrid material, with a mix between hard plastic and soft silicon. When it comes to 3D-printing, usually ABS and PLA are used as the industry standard. However, if you are looking to create bending prototypes, these two fall short. TPU on the other hand is very flexible in nature. It can bend easily without affecting its design, durability and strength, with it even coming with a mild “self-healing” ability.

TPU vs Popular 3D-printing Polymers

TPU works well if you are looking for flexibility, very similar to PETG, a polymer we featured in a previous article. Lets see how it compares with PETG as well as the other popular 3D-printing materials, ABS and PLA.

 

Filament Special Properties Uses Strength Flexi-

bility

Dura-

bility

Print

Skills

Print

Temp.

(˚C)

Bed

Temp.

(˚C)

ABS Durable, Impact Resistant Functional Parts 2/3 2/3 3/3 2/3 210 – 250 50 – 100
PLA Easy to Print, Biodegradable Consumer Products 2/3 1/3 2/3 1/3 180 – 230 No
PETG Flexible, Durable All-Rounder 2/3 3/3 3/3 2/3 220 – 235 No
TPU Extremely Flexible, Rubber-Like Elastic Parts,

Wearables

1/3 3/3 2/3 3/3 225 – 235 No

Values courtesy of all3dp.

How Hard is TPU?

The flexible polymer also comes in different forms, most notable by the letter at the end, A or D, which refers to its hardness. This hardness is measured by different types of Shore hardness scales (for example Shore A00, Shore A and Shore D). The different Shore Hardness scales measures the resistance of a material to indentation.

 

  • Shore A00 Scale – measures rubbers and gels that are very soft.
  • Shore A Hardness Scale  measures the hardness rubbers that range in hardness from very soft to almost no flexibility at all, essentially the middle-ground scale.
  • Last is the Shore D Hardness Scale measures the hardness of hard rubbers, semi-rigid plastics and hard plastics.
Image courtesy of Smooth-On.

As you can see from the chart, these scales can overlap. For example, shoe heels with a Shore Hardness of 70A can also be converted into a Shore hardness of 22D.

Our results with TPU

This polymer is great, and we really enjoy its creative uses. We were able to obtain some TPU Shore 75A, so a bit harder than the heel of a formal shoe.

TPU Shore 75A in its granular form, then extruded through the NEXT 1.0, and the resultant filament.

Doing some tests on the filament, we wanted to see how well it would extrude in our NEXT Advanced Level Filament Extruder. The results were better than we expected. As you can see in the images above, the filament extruded quite easily, resulting in a clean egg-shell white roll of filament.

A roll of filament was extruded, and a 3D-printed 3devo logo for testing.

Once the roll was complete, we decided to see how it would handle 3D printing. Going for a simple 3devo logo, we also wanted to test its flexibility. True to its hardness rating, it was still able to deform a bit, pretty neat!

In the end, this polymer serves a great purpose at providing a filament that is very easy to print with, but also durable and very flexible. If you are looking for a filament that is a combines the benefits of rubber and plastic, then TPU is for you.

 

Is PETG the best filament in the 3D Printing Industry?

When it comes to 3D printing, information about filaments such as PLA and ABS is plentiful. However there is another filament out there –  PETG. With its strong, durable and ease of use characteristics, are making it more and more popular by the day. 3devo delves into what PETG is, how it compares to the aforementioned polymers in terms of printing and extrusion.

What is PETG?

 

 

Source: Pixabay

 

PETG first started as simply PET, or polyethylene terephthalate. PET had and still has many great uses, with its fibers being used everywhere from food packaging to plastic bottles, as well as other common plastic items. There are many variations of PET, such as ETE, PETP, PET-P, etc., however, the G in PETG stands for glycol. Glycol prevents crystallization in the thermoforming process (i.e. preventing it from turning hazy).

Thanks to the glycol, it means the classic PET is modified for extra durability. PETG has recently become very popular as 3D-printing filament due to this durability, so let’s take a closer look at what makes it so great.

Why did we choose to test PETG?

Source: 3devo testing area – PETG (Genius 80M) in its granular form.

 

PETG has quite a few beneficial properties, especially when it comes to applications such as 3D printing. It comes in a whole range of translucent colours, but here are some of its most common attributes:

 

Durable – regular PET becomes very hard and brittle when it starts overheating. PETG is also more flexible than ABS and PLA, too. The inclusion of glycol really helps here, making items such as a plastic bottle more comfortable to hold in the hand as well.

 

Temperature resistant – both minimal shrinkage and warping make it great for printing large objects.

 

Sticky – PETG is a bit sticky, this means that it would not be good to use it as a support structure for 3D printing models, but its layer adhesion is usually fantastic.

 

Good chemical resistance – great chemical resistance, with good water, acidic and alkalic resistance.

 

Tough – PETG is very strong. It’s not brittle, however, it can be easily scratched (more easily than ABS). It also has a high impact resistance, similar to that of polycarbonate.

 

Amorphous – excellent transparency and high gloss surface (great for artistic print items).

 

Environmentally friendly – recyclable and food safe. In medical applications, it also stands up to radiation and chemical sterilization techniques without changing color.
In short it combines the benefits of PLA (easy to print with) with the benefits of ABS (strong, durable and temperature resistant).

 

Common applications of PETG

Source: 3devo printed parts with in house made PETG filament (Genius 80M)

 

PETG is used in a variety of signage, packaging, industrial and medical applications:

 

  • Medical equipment such as braces and pharmaceutical packages
  • Protective guards/coatings
  • Bottles and food packaging
  • Guards and covers for electronic equipment
  • Point-of-purchase and graphic displays

Why PETG instead of PLA or ABS?

Source: 3devo 2.85mm spool PETG Genius 80M, made on the NEXT 1.0 Advanced Level Extruder

 

When it comes to printing with PETG, the above characteristics all help making it a great choice. As shown above extruding a roll is simple (you can visit our store if you’re in the market for an extruder), and printing is not too bad either (some users have made this their top choice of filament). We would not recommend printing everything with it as you might not always want your item to be so flexible, but below is a brief summary of how it compares with PLA and ABS.

 

PETG PLA ABS
Hardness Very flexible Not very flexible R105 to R110 (Harder)
Durability Very flexible Not very flexible More flexible
Food safe Food safe Food safe Not food safe
Heat bed Heated bed is not a must but it can be an advantage Doesn’t need a heated bed for 3D printing Needs a heated bed for 3D printing
Price Slightly more expensive than PLA (+/- 10%) Average price range Cheapest of the three
Recommended 3D printing temperature 220 to 250 °C for the hotend 190-220°C 230-250°C
Recommended print-bed temperature 50-60°C 50-70°C 80-120°C

Most makers out there say PETG isn’t the easiest to initially print with, as you first have to find that “sweet” spot if you want to create some quality prints.
We at 3devo really enjoy this practical polymer. PETG is very practical and easy of use when it comes to printing, and its combination of rigidity and mechanical properties makes it a great all rounder, perfect for your next 3D-printing idea. Don’t forget to check out our blog for more interesting articles.