Hdpe 3d printer filament

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FFF technology has many advantages, including the relative simplicity of the design of printers and the affordability of both devices and consumables. Moreover, the range of materials is perhaps the widest among all available technologies. As a rule, thermoplastics are used for printing, but there are exceptions - composite materials containing various additives, but based, again, on thermoplastics. In this section, we will try to talk about the most widely used materials in more detail, starting with the most popular types.

Polylactide (PLA)

Polylactide is one of the most widely used thermoplastics due to several factors. Let's start with the fact that PLA is known for its environmental friendliness. This material is a lactic acid polymer, which makes PLA a completely biodegradable material. The raw materials for the production of polylactide are corn and sugar cane. At the same time, the environmental friendliness of polylactide causes its fragility. Plastic easily absorbs water and is relatively soft. As a rule, PLA models are not intended for functional use, but serve as designer models, souvenirs and toys. Few practical industrial applications include the production of food packaging, drug containers and surgical sutures, as well as use in bearings that do not carry high mechanical loads (for example, in modeling), which is possible due to the material's excellent slip coefficient.

One of the most important factors for 3D printing applications is the low melting temperature of only 170-180°C, which contributes to relatively low power consumption and the use of inexpensive brass and aluminum nozzles. As a rule, extrusion is carried out at 160-170°C. At the same time, PLA solidifies quite slowly (glass transition temperature is about 50°C), which should be taken into account when choosing a 3D printer. The best option is a device with an open case, a heated work platform (to avoid deformation of large models) and, preferably, additional fans to cool the fresh layers of the model.

PLA has low shrinkage, i.e. loss of volume on cooling, which helps prevent warping. However, shrinkage has a cumulative effect as the dimensions of printed models increase. In the latter case, the build platform may need to be heated to evenly cool the printed objects.

The cost of PLA is relatively low, which adds to the popularity of this material.

Acrylonitrile butadiene styrene (ABS)

ABS plastic is perhaps the most popular thermoplastic used in 3D printing, but not the most common. This contradiction is explained by certain technical difficulties that arise when printing ABS. The desire of craftsmen to use ABS is determined by the excellent mechanical properties, durability and low cost of this material. In industry, ABS plastic is already widely used: the production of car parts, cases of various devices, containers, souvenirs, various household accessories, etc.

ABS plastic is resistant to moisture, acids and oil, has a fairly high temperature resistance - from 90°C to 110°C. Unfortunately, some types of material are destroyed by direct sunlight, which somewhat limits the application. At the same time, ABS plastic is easy to paint, which allows you to apply protective coatings on non-mechanical elements.

Despite a relatively high glass transition temperature of around 100°C, ABS has a relatively low melting point. Actually, due to the amorphous nature of the material, ABS does not have a melting point, as such, but 180 ° C is considered an acceptable temperature for extrusion, which is on the same level as the above-described PLA. The lower temperature spread between extrusion and glass transition allows ABS to cure faster than PLA.

The main disadvantage of ABS plastic can be considered a high degree of shrinkage during cooling - the material can lose up to 0.8% of its volume. This effect can lead to significant deformations of the model, twisting of the first layers and cracking. To combat these unpleasant phenomena, two main solutions are used. First, heated work platforms are used to help reduce the temperature gradient between the lower and upper layers of the model. Secondly, ABS 3D printers often use closed housings and control of the background temperature of the working chamber. This makes it possible to maintain the temperature of the applied layers at a level just below the glass transition threshold, reducing the degree of shrinkage. Full cooling is carried out after receiving the finished model.

The relatively low stickiness of ABS may require additional bonding aids such as adhesive tape, polyimide film, or applying an acetone solution of the ABS to the platform just prior to printing. For more information on how to avoid warping, see How to Avoid Warping 3D Printed Models.

While ABS does not pose a health risk at room temperature, heated plastic releases acrylonitrile fumes, a poisonous compound that can irritate mucous membranes and cause poisoning. Although the amount of Acrylonitrate produced in small scale printing is negligible, it is recommended that you print in a well ventilated area or use an exhaust hood. It is not recommended to use ABS plastic for the production of food containers and utensils (especially for storing hot food or alcoholic beverages) or toys for small children.

The good solubility of ABS in acetone is very useful, as it allows large models to be produced piece by piece and glued together, greatly expanding the capabilities of inexpensive desktop printers.

Polyvinyl alcohol (PVA)

Polyvinyl alcohol is a material with unique properties and special applications. The main feature of PVA is its water solubility. 3D printers equipped with dual extruders have the ability to print models with PVA support structures. Upon completion of printing, the supports can be dissolved in water, leaving a finished model that does not require mechanical or chemical roughening. Similarly, PVA can be used to create water-soluble master patterns for molds and molds themselves.

The mechanical properties of PVA are quite interesting. At low humidity, plastic has high tensile strength. With increasing humidity, strength decreases, but elasticity increases. The extrusion temperature is 160-175°C, which allows the use of PVA in printers designed for printing with ABS and PLA plastics.

Since the material easily absorbs moisture, it is recommended to store PVA plastic in dry packaging and, if necessary, dry before use. Drying can be done in a pottery kiln or an ordinary oven. As a rule, drying of standard coils takes 6-8 hours at a temperature of 60-80°C. Exceeding 220°C will cause the plastic to decompose, which should be taken into account when printing.

Nylon

Nylon is attractive due to its high wear resistance and low coefficient of friction. Thus, nylon is often used to coat friction parts, which improves their performance and often allows them to function without lubrication. Following the widespread use of nylon in industry, additive manufacturing has also become interested in the material. Attempts to print with nylon have been made almost since the early days of FDM/FFF technology.

In reality, there are several types of nylon produced by different methods and with slightly different characteristics. The most famous is nylon-66, created by the American company DuPont in 1935. The second most popular option is nylon-6, developed by BASF to circumvent the DuPont patent. These two options are very similar. In terms of 3D printing, the main difference is the melting point: Nylon-6 melts at 220°C, while Nylon-66 melts at 265°C.

Many hobbyists prefer to use commercially available nylon threads such as trimmer wire. The diameter of such materials often corresponds to the diameter of standard FFF materials, which makes their use tempting. At the same time, these products are usually not pure nylon. In the case of trimmer rods, the material consists of nylon and fiberglass for an optimal combination of flexibility and rigidity.

Fiberglass has a high melting point and therefore printing with these materials is prone to high nozzle wear and plugging.

Recently there have been attempts to commercially develop nylon-based printing materials specifically for FDM/FFF applications, including Nylon-PA6 and Taulman 680. These grades are extrudable at 230-260°C.

Because nylon readily absorbs moisture, store consumables in vacuum packaging or at least in a container with water-absorbent materials. A sign of excessively damp media will be steam escaping from the nozzle during printing, which is not dangerous, but may degrade the quality of the model.

When printing with nylon, it is not recommended to use a polyimide desktop coating as the two materials fuse together. As a coating, you can use adhesive tape with wax impregnation (masking tape). The use of a heated bed will help reduce the possibility of deformation of the model, similar to printing with ABS plastic. Due to the low coefficient of friction of nylon, extruders with studded feeders should be used.

The nylon layers have excellent adhesion, minimizing the chance of delamination.

Nylon is difficult to bond, making it difficult to print large multi-piece models. Alternatively, fusion of parts is possible.

Since heating nylon can release toxic fumes, it is recommended that you print in a well ventilated area or use an exhaust fan.

Polycarbonate (PC)

Polycarbonates are attractive due to their high strength and toughness, as well as resistance to high and low temperatures.

A potential health risk of printing is worth noting: the toxic and potentially carcinogenic compound bisphenol A is often used as a raw material. .

The extrusion temperature depends on the printing speed to avoid cracking, but the minimum temperature at 30mm/s can be considered as 265°C. When printing, the use of polyimide film is recommended for better adhesion to the desktop surface. The high susceptibility of polycarbonate to deformation requires the use of a heated platform and, if possible, a closed housing with heating of the working chamber.

Polycarbonate is highly hygroscopic (easily absorbs moisture), which requires storage in dry conditions to avoid the formation of bubbles in the applied layers. For extended printing in humid climates, even the print spool may need to be stored in a moisture-proof container.

High density polyethylene (HDPE, HDPE)

Arguably the most common plastic in the world, polyethylene is relatively rare among 3D printed materials. The reason for this is the difficulty in layer-by-layer manufacturing of models.

Polyethylene melts easily (130-145°C) and hardens quickly (100-120°C), as a result of which the applied layers often do not have time to set. In addition, polyethylene is characterized by high shrinkage, which provokes the twisting of the first layers and the deformation of the models as a whole during uneven solidification. Printing with polyethylene requires the use of a heated platform and a working chamber with accurate temperature control to slow down the cooling of the applied layers. In addition, you will need to print at high speed.

Difficulties in use are more than offset by the cheapness and availability of this material. Recently, several devices have been developed for processing plastic waste from HDPE (bottles, food packaging, etc.) into standard filaments for printing on FDM/FFF printers. Examples are FilaBot and RecycleBot. Due to the simplicity of design, RecycleBot devices are often assembled by 3D craftsmen.

Melting polyethylene releases harmful vapors, so it is recommended to print in well ventilated areas.

Polypropylene (PP, PP)

Polypropylene is a widely used plastic used in the production of packaging materials, dishes, syringes, pipes, etc. The material has a low specific gravity, is non-toxic, has good chemical resistance, is resistant to moisture and wear, and is quite cheap. Among the disadvantages of polypropylene, one can note the vulnerability to temperatures below -5 ° C and to direct sunlight.

The main difficulty in printing with polypropylene is the high shrinkage of the material during cooling - up to 2.4%. For comparison, the shrinkage of the popular but already problematic ABS plastic reaches 0.8%. Although polypropylene adheres well to cold surfaces, it is recommended to print on a heated platform to avoid deformation of models. The minimum recommended extrusion temperature is 220°C.

Polypropylene printing filaments are sold by Orbi-Tech, German RepRap, Qingdao TSD Plastic. Stratasys has developed a polypropylene simulant optimized for 3D printing called Endur.

Polycaprolactone (PCL)

Polycaprolactone (aka Hand Moldable Plastic, Mold-Your-Own Grips, InstaMorph, Shapelock, Friendly Plastic, Polymorph, Polymorphus, Ecoformax) is a biodegradable polyester with an extremely low melting point of about 60°C. In practice, this property creates certain problems in 3D printing, since not all 3D printers can be configured to work at such low temperatures. Heating polycaprolactone to the usual extrusion temperatures (about 200°C) causes a loss of mechanical properties and may lead to breakage of the extruder.

Polycaprolactone is non-toxic, making it suitable for use in the medical industry, and biodegradable. When ingested, polycaprolactone breaks down, which makes printing with this material safe. Due to the low melting point, there is no danger of burns when touching fresh models. The high plasticity of the material makes it possible to reuse.

Polycaprolactone is of little use for creating functional mechanical models due to its viscosity (glass transition temperature is -60°C) and low heat resistance (melting point is 60°C). On the other hand, this material is perfect for the production of mock-ups and food containers.

The material sticks easily to the surface of even a cold working table and is easy to paint.

Polyphenylsulfone (PPSU)

Polyphenylsulfone is a high-strength thermoplastic widely used in the aviation industry. The material has excellent chemical and thermal stability and practically does not burn. Polyphenylsulfone is biologically inert, which makes it possible to use this material for the production of tableware and food containers. Operating temperature range is -50°С - 180°С. Plastic is resistant to solvents and fuels and lubricants.

For all its merits, polyphenylsulfone is rarely used in 3D printing due to its high melting point, reaching 370°C. Such extrusion temperatures are beyond the power of most desktop printers, although printing is theoretically possible using ceramic nozzles. Currently, the only active user of the material is Stratasys, which offers industrial Fortus installations.

Polymethyl methacrylate (Acrylic, plexiglass, acrylic, PMMA)

Polymethyl methacrylate is a well-known organic glass. The material is durable, moisture resistant, environmentally friendly, easy to glue, plastic enough and resistant to direct sunlight.

Unfortunately, acrylic is not suitable for FDM/FFF printing for a number of reasons. Acrylic is poorly stored in the form of spools of thread, as constant mechanical stress leads to the gradual destruction of the material. To avoid bubbles, the print resolution must be high, with a precision almost impossible for home printers. Acrylic's rapid curing requires strict environmental control of the working chamber and high print speeds. Again, the print speeds of FDM/FFF printers are inversely related to print resolution, which exacerbates the problem.

However, attempts are being made to print with acrylic, and some of them are producing relatively positive results. However, when creating sufficiently strong models, it is not yet possible to avoid the formation of bubbles and achieve the usual transparency of the material. At the moment, the best results with acrylic are shown by another printing technology - multi-jet modeling (MJM) from 3D Systems. In this case, a photopolymer version of acrylic is used. Stratasys has also made significant progress using its own photopolymer acrylic simulant VeroClear on Objet Eden printers. It is hoped that the high demand for acrylic will lead to the emergence of composite materials based on polymethyl methacrylate, designed specifically for FDM/FFF printing.

Polyethylene terephthalate (PET, PET)

Polyethylene terephthalate - this complex name hides a material used for the production of plastic bottles and other food and medical containers.

The material has a high chemical resistance to acids, alkalis and organic solvents. The physical properties of PET are also impressive with high wear resistance and tolerance to a wide temperature range from -40°C to 75°C. Among other things, the material is easily machined.

Printing with PET is somewhat problematic due to the relatively high melting point of up to 260°C and significant cooling shrinkage of up to 2%. Using PET as a consumable requires approximately the same conditions as printing with ABS.

Achieving transparency of models requires rapid cooling to pass the glass transition threshold of 70°C - 80°C.

The material has become the focus of attention of 3D craftsmen using used containers as raw materials for home production of 3D printing consumables. Recycling devices such as FilaBot or RecycleBot are used to make threads.

High-impact polystyrene (HIPS)

High-impact polystyrene is widely used in industry for the production of various household products, building materials, disposable tableware, toys, medical instruments, etc.

When 3D printed, polystyrene shows physical properties very similar to the popular ABS -plastic, which makes this material more and more popular among 3D craftsmen. The most attractive feature of polystyrene is the difference from ABS in terms of chemical properties: polystyrene is quite easily amenable to the organic solvent Limonen. Since Limonene has no effect on ABS plastic, it is possible to use polystyrene as a material for building soluble support structures, which is extremely useful when building complex, interlaced models with internal supports. Compared to the convenient, water-soluble polyvinyl alcohol (PVA) plastic, polystyrene compares favorably with relatively low cost and resistance to humid climates that make PVA difficult to work with.

It is worth bearing in mind that some ABS manufacturers mix somewhat cheaper polystyrene into their consumables. Accordingly, models made from such materials can be dissolved in Limonene along with supporting structures.

When polystyrene is heated to extrusion temperature, toxic fumes can be released, so printing in a well-ventilated area is recommended.

Wood simulants (LAYWOO-D3, BambooFill)

LAYWOO-D3 is a recent development for printing wood-like models. The material consists of 40% natural wood chips of microscopic size and 60% binder polymer. The LAYWOO-D3 is very easy to handle, being virtually warp-free and does not require the use of a heated platform. According to the manufacturers, the polymer is non-toxic and completely safe.

The unique properties of the material allow you to achieve different visual results when printing with different nozzle temperatures. The operating temperature range is 180°C-250°C. As the extrusion temperature increases, the shade of the material becomes progressively darker, allowing it to simulate different types of wood or annual rings.

Finished models lend themselves perfectly to mechanical processing - grinding, drilling, etc. In addition, the products are easily painted, and unpainted models even have a characteristic woody smell.

Unfortunately, the cost of the material is almost four times higher than the price of popular materials such as PLA and ABS plastics. As popularity is projected to grow, the material should become more accessible.

Alternative materials are currently being developed and tested, such as BambooFill from the Dutch company ColorFabb.

Sandstone simulants (Laybrick)

Composite material from inventor Kai Parti, responsible for the revolutionary LAYWOO-D3 wood simulant. This time, Kai set his sights on sandstone imitation, using a tried and tested method of mixing a binder with a filler, in this case mineral.

Laybrick allows you to produce objects with different surface textures. At low extrusion temperatures of the order of 165°C-190°C, the finished products have a smooth surface. Increasing the printing temperature makes the material rougher, up to a high degree of resemblance to natural sandstone at extrusion temperatures above 210°C.

The material is easy to work with no need to heat the work platform, does not show significant deformation when shrinking and does not produce toxic fumes when heated. The only drawback can be considered a rather high cost of the material, which is largely due to limited production.

Metal Simulators (BronzeFill)

Metals have attracted additive manufacturing enthusiasts since the early days of 3D printing technology. Unfortunately, printing with pure metals and alloys causes a lot of difficulties that are insurmountable for most 3D printing methods. Fully functional metal products can only be produced using technologies such as SLS, DLMS or EBM, which require the use of industrial plants that cost hundreds of thousands of dollars. At the same time, metal imitators are successfully used in 3D inkjet printing (3DP), where products are formed from metal powders, the particles of which are held together by an applied binder material. In FDM/FFF printing, metal simulants are just emerging.

An interesting example is BronzeFill - in fact, transparent PLA-plastic filled with bronze microparticles. The material, currently in beta testing, must prove suitability for use in any printer designed to work with polylactide.

Finished products are easy to polish, achieving a high external resemblance to all-metal products. At the same time, it should be taken into account that the binding element of the material is thermoplastic, with appropriate mechanical and temperature limitations.

How to choose the right printing material

After you have chosen and purchased your 3D printer, to start creating and implementing any of your ideas, you need to choose the right printing material. Read our article on how to do this.

The print material is like ink in a regular printer, except that it's plastic. It is available in large quantities of color, diameter, diameter, type of provision (the most common is a coil, as shown in the image). Now let's go through the main criteria by which you need to choose the one that suits you and your printer.

Material type

In terms of type selection, there are currently two most popular materials: ABS plastic and PLA plastic. ABS is a material familiar to you from LEGO bricks. It is a very durable thermoplastic with little flexibility and is suitable for many uses. It can be sanded, painted, and can be easily glued to other ABS parts with a special adhesive. It is very resistant to mechanical stress, including thermal stress, and melts at a temperature of 210 degrees Celsius. When printing ABS, the working platform is usually heated up to 110 degrees, otherwise the part may deform and even crack when it cools. For a long time, ABS has been a favorite material for the 3D printing community, although the recent development of PLA plastic has changed this.

PLA is a polymer plastic made from corn or sugar cane. It is not very recyclable, but under the right environmental conditions it is biodegradable. PLA is much more environmentally friendly and smells a little like maple syrup when printed. This is a fairly strong plastic, although more fragile than ABS. It is also less temperature resistant than ABS and melts at 180 degrees Celsius. Heated platform optional. Although if you have it, heating it to a temperature of 60 degrees will help make the print better. If the surface is heated, PLA can print on normal smooth glass as well. This material is cooled for a long time, so the presence of an additional cooling system will also help improve print quality. PLA manufacturers offer it in completely different colors that are pleasing to the eye.

Other commonly suggested materials, especially for DIY printers, are high-density polyethylene (HDPE) as well as polyvinyl alcohol (PVA), and experiments are ongoing with various plastics.

When choosing a material, consider the environment in which the printer will be used. If the printer will be in an open, well-ventilated area, then ABS is your choice, as it will allow for more processing after the part is made. If the printer will stand in a closed room or classroom, then to avoid the emission of harmful impurities during printing, it is better to use more “green” PLA plastic. A rougher rule. If your printer supports PLA, then we recommend using it in 95% of cases.

Material (thread) diameter

Once you have chosen the type of material, you will need to think about the diameter of the thread. The vast majority of printers use 1.75 mm filament for printing. Proponents of smaller filament diameters say that it is easier to make an extruder drive and thermal head, as they require less material to heat up and are easier to feed into the extruder. Although initially, filaments with a diameter of 3 mm were prepared for most printers.

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