SDL - selective deposition lamination. Household and amateur use

The history of 3D printing dates back to the 1980s, but for a long time it was seen as something with a limited scope of use and incredible prices. Relatively recently, it began to gain popularity: new 3D printing technologies are being developed, which are of interest not only in narrow areas, but also among companies from a wide variety of areas of activity. They actively use and invest in 3D printing to achieve high profitability and reduce production costs for even the most complex products.

Principle of operation

To give a brief explanation of the essence of 3D printing, it is a method of manufacturing three-dimensional products based on their digital models by sintering or gluing a homogeneous material. Regardless of what technology is used for this, the process consists of a gradual layer-by-layer build-up of a specific object. From this point of view, 3D printing is fundamentally different from traditional materials processing, which often involves a “take a blank and remove everything unnecessary” approach, which is accompanied by a large amount of waste. The 3D printing process starts from scratch and the required product gradually “grows” by adding new layers, and there is virtually no waste (or sometimes present in relatively small quantities). Another name for 3D printing is associated with layer-by-layer formation - additive technologies (from the English word additive - add)

All products are printed on a 3D printer, which works with certain consumables under control software. Simplified, printing technology consists of the following steps:

• a 3D model of the desired object is created according to certain rules;
• a file with a three-dimensional model is loaded into a slicer program, which breaks it into layers and calculates the print job in the form of a special code;
• the required printing parameters are indicated;
• the printing process starts directly or the code is written to the memory card for delayed printing;
• A 3D model is reproduced: consumables are applied in layers according to the shape and the finished product is formed.

Depending on the technologies and materials used, the resulting products can be used in mechanical engineering, to create injection molds, as well as for visualization and prototyping of various objects.

Variety of technologies

Today, the number of existing technologies used in 3D printing has already gone beyond the top ten, even without taking into account similar methods, which, due to legal restrictions, are given different names. Among them, there are 3 main ones with some variations, which differ in the materials used, accuracy and principles of operation, as well as the printing devices themselves. Each printing device is designed for a specific technology.

This 3D printing method allows you to create three-dimensional samples from a liquid photopolymer, which, when exposed to laser radiation, turns into a solid state. Using SLA technology, an object is created on a platform immersed in a photopolymer, where a laser beam is directed. It ensures crystallization of the material, and thus the first layer of the future product is formed. The platform is shifted each time by the thickness of the layer, the empty space is filled with liquid polymer, and the baking process is repeated until the desired object is built.

The main advantage of stereolithography is high accuracy. Different printer models make it possible to achieve a layer thickness of 6-10 microns (for comparison, the thickness of a human hair ranges from 50-100 microns). Due to this, the use of SLA is most in demand in medicine (for example, dentistry) and jewelry production. On the other hand, industrial 3D printers allow you to create objects with dimensions up to several meters.

One of the variations and worthy alternatives to SLA is the relatively young technology of LED 3D printing DLP (Digital Light Processing). It involves processing the same liquid photopolymers, but their crystallization occurs under the influence of LED light projectors, which first form the contour of the layer and then fill it. It also provides good accuracy (up to 15 microns) and a wide variety of physicochemical and mechanical properties of photopolymer resins and their color solutions. Compared to SLA technologies, it has an additional advantage - higher printing speed.

This 3D printing technology is the most common today, since it does not require expensive equipment, and working with consumables (plastic thread or rod) is not particularly difficult. The rights to the FDM acronym and the name Fused Deposition Modeling itself belong to Stratasys. To get around patent restrictions, representatives of the RepRap project proposed their own name FFF or Fused Filament Fabrication. In practice, FFF 3D printing technology essentially means the same thing as FDM.

The principle of operation in this case is as follows: the extruder head heats the plastic threads to a semi-liquid state and releases them in doses onto the working platform. The layers are applied one by one, fused together and hardened, gradually building up a product that fully corresponds to the digital prototype.

SLS (Selective Lazer Sintering) technology involves the use of powder consumables. The latter uses powder forms of bronze, steel, nylon, titanium, etc. But some powders have explosive properties and therefore require storage exclusively in chambers with nitrogen. This version of 3D technology, which is used for printing with both plastic and metal, is often used in the industrial field to create durable elements.

Due to sintering with a laser beam, the structure of the desired object is built up layer by layer, the density of which will depend on the maximum energy of the emitter. Its contours are gradually drawn in accordance with the digital model. In this case, sintering often occurs at high temperatures, so it takes a long time for the finished parts to cool (up to a whole day).

One of the features of SLS technology is the minimal probability of part failure during the 3D printing process, since unused powder material will serve as support for its hinged elements.

Application of 3D printing

The scope of application of 3D printing technologies has virtually no boundaries. Another name for this is rapid prototyping. So, 3D printing may be indispensable for:

• small-scale production, when the production of small batches, exclusive or personalized objects (objects of art, game figures, experimental samples) requires minimal time from development to creation of the finished product, since the work of designers is greatly simplified;
• the automotive and aerospace industries, where 3D technologies open up the possibility of metal printing of spare parts and objects of any complex shape, which are often stronger and lighter compared to traditionally produced products;
• medicine, where implants (for example, for prosthetics in dentistry) and medicines are already being created on 3D printers, and scientists are working on the development of 3D bioprinting technologies to create organs, living tissues and bones;
• construction, where 3D technologies are used not only to create architectural models of houses from entire microdistricts with the necessary infrastructure, but also to print full-fledged building materials and even entire buildings;
• fashion industry and creative people who get the opportunity to reveal their talent using 3D modeling and realize their wildest ideas.

On at this stage 3D printing is not developed enough to carry out industrial revolution. But the production of complex volumetric products with high precision is a market that is ideally suited for the implementation and further improvement of these unique technologies of the future. It is quite possible that in the near future everyone will be able to acquire a printer for creating three-dimensional samples, and then new horizons in creating three-dimensional samples will be limited only by human imagination.

Science fiction writers wrote about the possibility of creating machines that literally “grow” houses back in the 19th century. What can I say, even twenty years ago this technology seemed incredible. But today it has already entered our everyday life. No one will be surprised to see construction site, in which a person and a machine work in tandem: a system operator and a tap with a feeding nozzle construction mixture. The topic of this material from HouseChief.ru is the use of a 3D printer in construction. We will not talk about science fiction, but about real experience in this direction and will give examples of ready-made objects, as well as talk about the possibility of purchasing such a device.

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What is a 3D printer and what is it used for?

Modern construction technologies are a very popular product; specialists in this field are welcomed with open arms, luring them away from competitors. The race is almost cosmic - whoever brings an innovation to the market first will receive super benefits. It is not surprising that the hardworking Chinese not only invented, but also began to produce construction printers almost en masse. They showed the world how just one unit built an entire village in 30 days. Other countries are not far behind them; domestic producers have also joined this business and are on their side so far obvious benefit– the construction printer device is quite large.

So what is a 3D printer and how does it work? The main task of the mechanism is the sequential layer-by-layer supply of the construction mixture to the site. The software controls the servo drive, forcing it to leave space for window and door openings and laying communications. The construction material is ordinary sand concrete, as well as mixtures based on gypsum, fiberglass and geopolymers.

The operation of the device requires preliminary preparation of the site and building design.

And finally, an undoubted advantage is a significant reduction in construction time. Work on a 3D printer can be carried out around the clock; it does not require special lighting or days off.

Before you decide to buy a construction machine, pay attention to its disadvantages:

• It is impossible to use vibrated concrete for construction; mixtures with high speed setting and hardening;
• a clear method for reinforcing structures has not yet been developed;
• it is not possible to remove air using vibration treatment; air cavities may form, which reduces the strength of the structure;
• You can operate a 3D printer only at positive temperatures in dry weather.

Modern technologies and manufacturers of printers for 3D printing houses

Contour Crafting technology was invented by Iranian B. Khoshnevis. Currently, this scientist continues his research under the patronage of the US Navy and NASA. Most of his work is still classified, but the basic principle is known - it involves applying the mixture using an extruder. The scientist is working on the task of completely automating the process, including the installation of fittings.

The Italian Enrico Dini took a different path in his development: he proposes to use not just one extruder, but a set of hundreds of nozzles, which is attached to a movable manipulator. The operation of the machine resembles jet printer, he sprays a mixture of sand and metal oxides with magnesium chloride. The technology is called D-Shape.

Domestic designer Andrei Rudenko took his brainchild, the StroyBot construction printer, to the USA. After several unsuccessful attempts to attract attention to his work, he finally found a great way to advertise his product - he built part of a hotel for a Filipino entrepreneur. He used geopolymer concrete as a working mixture.

The Yekaterinburg company Spetsavia has real experience in production and sales in this area. Today, this domestic manufacturer offers 7 options for construction printers of different sizes and purposes.

Spetsavia's competitor is the Irkutsk concern Apis Cor. He abandoned the idea of ​​​​using a portal structure and focused on telescopic manipulators that move freely on a rotating platform. The unit is very mobile and can be transported in a regular truck. It is already actively used for building houses using 3D printers in Russia.

The most famous manufacturer of construction machines is the Chinese company WinSun. Khoshnevis accused the Chinese of stealing his technology. Even if this is so, WinSun, unlike the Iranian scientist, has already brought this technology to the masses. They entered into agreements to build housing in war-torn areas of Iraq.

Educational video: what can be done with a 3D printer

A construction machine can create entire objects, such as houses, or produce panels and other building materials. A clear example of how a 3D printer works in this video:

Examples of 3D printing houses in photographs

To better imagine the process and the result, we invite you to see what houses printed on a 3D printer look like in a small photo gallery:

1 out of 10

Where can you buy a construction 3D printer and how much does it cost?

Construction 3D printing is undoubtedly the future. But while these technologies are being improved, it will be another 10 years before such machines appear in all construction organizations or will become available to private developers. A construction 3D printer can be bought in Yekaterinburg from Spetsavia. A construction 3D printer that prints a house has a price of 4.6 million rubles. Agree, it is a little expensive for the construction of one private house. But for a small construction company- quite reasonable price.

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Classmates

3D printing- this is the performance of a series of repeating operations associated with the creation of three-dimensional models by applying a thin layer of consumables to the desktop of the installation, moving the desktop down to the height of the formed layer and removing waste waste from the surface of the desktop. Printing cycles continuously follow each other: the next layer is applied to the previous layer of materials, the table is lowered again and so on until elevator(this is the name of the desktop that the 3D printer is equipped with) there will not be a finished model.

There are several 3D printing technologies that differ from each other in the type of prototyping material and methods of its application. Currently, the most widespread 3D printing technologies are: stereolithography, laser sintering of powder materials, inkjet modeling technology, layer-by-layer printing with molten polymer filament, powder gluing technology, lamination of sheet materials and UV irradiation through a photomask. Let us characterize the listed technologies in more detail.

Stereolithography

Stereolithography– also known as Stereo Lithography Apparatus or abbreviated as SLA, due to the low cost of finished products, has become the most widespread among 3D printing technologies.

SLA technology consists of the following: a scanning system directs a laser beam at the photopolymer, under the influence of which the material hardens. The photopolymer is a brittle and hard translucent material that warps under the influence of atmospheric moisture. The material is easy to glue, process and paint. The desktop is located in a container with a photopolymer composition. After passing the laser beam and curing the next layer, its working surface moves down by 0.025 mm - 0.3 mm.

SLA technology

Equipment for SLA printing is manufactured by F&S Stereolithographietechnik GmbH, 3DSystem, as well as the Institute for Laser and information technologies RAS.

Below are chess pieces created using the SLA printing method.

Chess pieces created using SLA printing

Laser sintering of powder materials

Laser sintering of powder materials– also known as Selective Laser Sintering or simply SLS is the only 3D printing technology that can be used to produce metal molds for metal and plastic casting. Plastic prototypes have good mechanical properties, thanks to which they can be used for the production of fully functional products.

SLS printing uses materials similar in their properties to structural grades: metal, ceramics, powder plastic. Powder materials are applied to the surface of the desktop and baked with a laser beam into a solid layer that corresponds to the cross-section of the 3D model and determines its geometry.

SLS technology

Equipment for SLS printing is manufactured by the following factories: 3D Systems, F& S Stereolithographietechnik GmbH, The ExOne Company / Prometal, EOS GmbH.

The picture shows the sculptural model “Keep it Up,” made using SLS printing.

Sculptural model “Keep it up”, made using SLS printing, by Luca Ionescu

Layer-by-layer printing with molten polymer filament

Layer-by-layer printing with molten polymer filament– also known as Fused Deposition Modeling or simply FDM, is used to produce individual products that are close in their functionality to serial products, as well as for the production of lost wax molds for metal casting.

FDM printing technology is as follows: an extruding head with a controlled temperature heats filaments made of ABC plastic, wax or polycarbonate to a semi-liquid state, and with high precision delivers the resulting thermoplastic modeling material in thin layers onto the working surface of the 3D printer. The layers are applied to each other, connected to each other and hardened, gradually forming the finished product.

FDM printing technology

Currently, 3D printers with FDM printing technology are manufactured by Stratasys Inc.

The picture shows a model printed by a 3D printer using FDM printing technology.

Model printed by a 3D printer using FDM printing technology

Inkjet modeling technology

Simulation technology or Ink Jet Modeling has the following proprietary subtypes: 3D Systems (Multi-Jet Modeling or MJM), PolyJet (Objet Geometries or PolyJet) and Solidscape (Drop-On-Demand-Jet or DODJet).

The listed technologies operate on the same principle, but each of them has its own characteristics. Supporting and modeling materials are used for printing. Supporting materials most often include wax, and modeling materials include a wide range of materials that are similar in their properties to structural thermoplastics. The print head of a 3D printer applies supporting and modeling materials to the working surface, after which they are photopolymerized and mechanically leveled.

Inkjet modeling technology makes it possible to obtain colored and transparent models with different mechanical properties; these can be either soft, rubber-like products or hard, plastic-like products.

Inkjet modeling technology

Printers for 3D printing using inkjet modeling technology are manufactured by the following companies: Solidscape Inc, Objet Geometries Ltd, 3D Systems.

Powder bonding technology

– aka Binding powder by adhesives allows you not only to create three-dimensional models, but also to paint them.

Printers with binding powder by adhesives technology use two types of materials: starch-cellulose powder, from which the model is formed, and water-based liquid glue, which glues the layers of powder. The glue comes from the print head of the 3D printer, binding the powder particles together and forming the outline of the model. After printing is complete, excess powder is removed. To give the model additional strength, its voids are filled with liquid wax.

Powder bonding technology

Legend:

1-2 – the roller applies a thin layer of powder to the working surface; 3 – the inkjet print head prints with drops of a binding liquid on a layer of powder, locally strengthening part of the solid section; 4 – process 1-3 is repeated for each layer until the model is ready, the remaining powder is removed

Currently, 3D printers with powder bonding technology are manufactured by Z Corporation.

Lamination of sheet materials

Lamination of sheet materials– also known as Laminated Object Manufacturing or LOM, involves the production of 3D models from paper sheets using lamination. The outline of the next layer of the future model is cut out with a laser, and unnecessary trimmings are cut into small squares, which are subsequently removed from the printer. The structure of the finished product is similar to wood, but is susceptible to moisture.

Sheet materials lamination technology

Until recently, 3D printers for laminating sheet materials were produced by Helisys Inc, but the company has now stopped producing such equipment.

An object printed on a 3D printer using sheet material lamination technology is shown in the photo below.

Model printed with a 3D printer using LOM technology

Ultraviolet irradiation through a photomask

Ultraviolet irradiation through a photomask– also known as Solid Ground Curing or SGC, involves the creation of ready-made models from layers of photosensitive plastic sprayed onto the working surface. After applying a thin layer of plastic, it is treated with ultraviolet rays through a special photomask with an image of the next section. Unused material is removed using a vacuum, and the remaining hardened material is re-irradiated with hard ultraviolet light. The cavities of the finished product are filled with molten wax, which serves to support the following layers. Before applying the next layer of photosensitive plastic, the previous layer is mechanically leveled.

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We have already said that there are a lot of 3D printing technologies, and either new ones or modifications of already known ones appear regularly, so we will not try to embrace the immensity and will tell in more detail only about the most interesting and common ones.

Let's start, of course, with stereolithography, which historically was the very first.

Stereolithography Apparatus (SLA)

The starting product is a liquid photopolymer to which a special hardening agent has been added, and this mixture resembles the well-known epoxy resin, only in its normal state it remains liquid, but polymerizes and becomes solid under the influence of an ultraviolet laser.

Naturally, a laser cannot immediately create the entire model in the thickness of the polymer, and we can only talk about sequential construction in thin layers. Therefore, a movable substrate with holes is used, which, using a micro-elevator, is immersed in the photopolymer to the thickness of one layer, then the laser beam illuminates the areas to be cured, the substrate is immersed to another thickness of one layer, the laser operates again, and so on.

It does not come without significant difficulties. Firstly, the requirements for the photopolymer itself are quite contradictory: if it is thick, then it is easier to polymerize, but it is more difficult to ensure a smooth surface after each immersion step; you have to use a special ruler, which at each step passes over the surface of the liquid and levels it. A large amount of hardener at a fixed laser power will reduce required time influence, however, the inevitable background illumination “spoils” the surrounding volume of the polymer and shortens the possible period of its use.

Secondly, complete polymerization of each layer would take a lot of time, so illumination is carried out to a level at which the layer acquires only the minimum required strength, and subsequently the finished model, having previously been washed from residual liquid polymer, must be irradiated with a powerful source in a special chamber in order for polymerization reached 100%.

The advantages of the technology are clear:

• you can obtain a very high printing resolution, i.e., achieve good accuracy in the manufacture of models, which vertically depends mainly on the capabilities of the elevator that immerses the platform, and is usually 100 microns, and in the best devices even less, up to 25–50 microns; horizontal accuracy is determined by focusing the laser beam; a “spot” diameter of 200 microns is quite realistic; accordingly, the quality of the surface even without additional processing is high;
• you can get very large models, measuring up to 150x75x55 cm and weighing up to 150 kg;
• the mechanical strength of the resulting samples is quite high, they can withstand temperatures up to 100 °C;
• there are very few restrictions on the complexity of the model and the presence of small elements;
• low amount of waste;
• ease of finishing, if required at all.

• limited choice of materials for making models;
• impossibility of color printing and combination different materials in one cycle;
• low printing speed, maximum 10–20 millimeters per hour vertically;
• very large dimensions and weight: for example, one of the 3D Systems ProX 950 SLA devices weighs 2.4 tons with dimensions of 2.2 × 1.6 × 2.26 m.

Although we mentioned the limited range of consumables, there is still a choice, and you can get models with different properties: with increased heat resistance, flexible, with high resistance to abrasives. However, the colors are worse: very limited quantities are available, including white, gray, and also translucent.

But the main disadvantage is the high price of both the printers themselves (hundreds of thousands of dollars) and consumables (two to three thousand dollars for a 10-kilogram cartridge), so SLA devices are not available in any mass.

Selective Laser Sintering (SLS)

This method appeared at about the same time as SLA, and even has much in common with it, only instead of liquid, a powder with a particle diameter of 50–100 microns is used, distributed in thin uniform layers in a horizontal plane, and then a laser beam sinteres the areas to be curing on this layer of the model.

The starting materials can be very different: metal, plastic, ceramics, glass, foundry wax. The powder is applied and leveled over the surface of the work table with a special roller, which removes excess powder during the reverse pass. Then a powerful laser works, sintering the particles with each other and with the previous layer, after which the table is lowered by an amount equal to the height of one layer. To reduce the laser power required for sintering, the powder in the working chamber is preheated to almost the melting temperature, and the laser itself operates in a pulsed mode, since peak power is more important for sintering than the duration of exposure.

Particles can melt completely or partially (along the surface). The unbaked powder remaining around the cured layers serves as support for creating overhanging elements of the model, so there is no need to form special support structures. But at the end of the process, this powder must be removed both from the chamber, especially if the next model will be created from a different material, and from the cavities of the already made model, which can only be done after it has completely cooled.

Finishing, such as polishing, is often required as the surface may be rough or have visible lamination. In addition, the material can be used not only pure, but also in a mixture with a polymer or in the form of particles coated with a polymer, the remains of which must be removed by burning in a special oven. For metals, the resulting voids are simultaneously filled with bronze.

Because the we're talking about about the high temperatures required for sintering, the process occurs in a nitrogen environment with a low oxygen content. When working with metals, this also prevents oxidation.

Serially produced SLS units allow you to work with fairly large objects, up to 55x55x75 cm.

The dimensions and weight of the installations themselves, as well as the SLA, are quite impressive. Thus, the Formiga P100 device shown in the photo, with the rather modest dimensions of the manufactured models (working area 20 × 25 × 33 cm), has dimensions of 1.32 × 1.07 × 2.2 m with a weight of 600 kg, and this does not take into account such options such as powder mixing installations and cleaning and filtration systems. Moreover, the P100 can only work with plastics (polyamide, polystyrene).

Technology options are:

1. Selective Laser Melting (SLM), which is used to work with pure metals without polymer impurities and allows you to create finished sample in one stage.
2. Electron Beam Melting (EBM) using an electron beam instead of a laser; this technology requires working in a vacuum chamber, but even allows the use of metals such as titanium.

There are also names such as Direct Metal Fabrication (DMF), and Direct Manufacturing.

The SPRO 250 Direct Metal printer manufactured by 3D Systems, which, as the name implies, can work with metals using SLM technology, with a working chamber of 25x24x32 cm, has a size of 1.7x0.8x2 meters and a weight of 1225 kg. The stated speed is from 5 to 20 cubic centimeters per hour, and we can conclude that a model with a volume of a glass will take at least 10 hours to produce.

• wide range of materials suitable for use;
• allows you to create very complex models;
• the speed is on average higher than that of SLA and can reach 30–40 mm per hour vertically;
• can be used not only for creating prototypes, but also for small-scale production, including jewelry;

• a powerful laser and a sealed chamber are required, in which an environment with a low oxygen content is created;
• lower maximum resolution than SLA: minimum layer thickness 0.1–0.15 mm (depending on the material, it may be slightly less than 0.1 mm); horizontally, as in SLA, the accuracy is determined by the focusing of the laser beam;
• a long preparatory stage is required to warm up the powder, and then you need to wait for the resulting sample to cool down so that the remaining powder can be removed;
• in most cases finishing is required.

The price of SLS installations is even higher than SLA and can reach millions of dollars. However, we note that in February 2014 the patents for SLS technology expired, so it is quite possible to predict an increase in the number of companies offering such equipment, and, accordingly, a noticeable reduction in prices. However, it is unlikely that in the coming years prices will drop so significantly that SLS printing will become affordable even for small businesses, not to mention private enthusiasts.

Due to the wide variety of materials, we do not provide indicative prices.

Multi Jet Modeling (MJM) method

Printers based on this technology are produced by 3D Systems. Due to patent restrictions, there are also names used by other printer manufacturers: PolyJet(Photopolymer Jetting, a Stratasys company), DODJet(Drop-On-Demand Jet, a Solidscape company). Of course, the differences are not only in the names, but the basic principles are similar.

The process is very similar to conventional inkjet printing: the material is fed through small diameter nozzles arranged in rows on the print head. The number of nozzles can be from several pieces to several hundred. Of course, the material is not liquid at room temperature: it is first heated to its melting point (usually not very high), then fed into the head, applied in layers and hardened. Layers are formed by moving the head in a horizontal plane, and vertical displacement when moving to the next layer, as in previous cases, is ensured by lowering the work table. The DODJet version adds a layer processing step with a milling head.

The materials used for MJM printers are plastics, photopolymers, special wax, as well as materials for medical implants, dental casts and prostheses. A combination of different materials is also possible: unlike the previous two technologies, model elements protruding at a large angle or horizontal jumpers to avoid sagging require the use of supporting structures, which have to be removed during finishing. To avoid doing this manually, you can use a material with a lower melting point for the supports than for the model itself, and then remove it by melting it in a special oven. Another option is to use material for supports, which is removed by dissolving in a specialized solution, and sometimes simply in water.

The use of a photopolymer, as in stereolithography, will require ultraviolet curing, so the printed layer is illuminated by a UV lamp. Wax hardens when it cools naturally. Of course, wax models are not particularly durable, but they are very easy to use when making casting molds.

As in conventional inkjet printing, the use of materials of different colors will allow you to create multi-color models in one cycle, and mixing base colors will make it possible to obtain many shades. In addition, you can combine materials with different properties in one model - for example, hard and elastic.

Let's move on to examples.

The compact Solidscape 3Z max printer, with its own dimensions of 56×50×42 cm and a weight of 34 kg, allows you to create models with dimensions up to 152×152×101 mm, providing a resolution of 5000×5000 dpi (197×197 dots/mm) along the X, Y and 8000 dpi (158 dots/mm) along the Z axis. Its price is about $50,000, but there are cheaper models in the 3Z line.

In these printers, two types of wax are used: a more refractory one (95–115 °C) for the models themselves, and a low-melting one (50–72 °C) for the supporting structures, which are then removed at low temperatures using a special solution.

Approximate cost: wax for 3Z LabCast models - $260–270 for 360 g, wax for supports $200–210 for 230 g. As you can see, such consumables cannot be considered very cheap.

• very small layer thickness (from 16 microns) and surface construction resolution (up to 8000 dpi) are achievable;
• possibility of multi-color printing and combination of materials with different properties;
• printers can be quite compact, especially compared to the previous two technologies.

• for models with overhanging or horizontally protruding elements, supports are required that have to be removed in one way or another;
• limited choice of materials for work.

Layer-by-layer bonding of films (Laminated Object Manufacturing, LOM)

Thin sheets of material are cut with a laser beam or a special blade, and then connected to each other in one way or another. To create 3D models, not only plastic, but even paper, ceramics or metal can be used.

Since there are a lot of different models, let's look at one very typical example - the Mcor IRIS color 3D printer, demonstrated by Mcor Technologies at the SolidWorks World 2013 exhibition. It uses as a material the most ordinary sheets of A4 or Letter paper with a density of 160 g/m², which are painted in the required color. The print resolution is 5760x1440x508 dpi, and the maximum size of created objects is 256x169x150 mm. This provides full-color printing with more than a million colors.

The photo shows a 3D printer on a stand; The dimensions of the printer itself are 95×70×80 cm, weight 160 kg. The stand, measuring 116x72x94 cm and weighing another 150 kg, hides a color 2D printer.

The creation of the model is carried out in several stages: in the first, a stack of paper is loaded into a 2D printer and the desired layer is printed in color on each sheet.

Then the printed sheets are transferred by the operator to a 3D printer, where a special blade is used to make a cut on each of them along the border of the printed image, and then the sheets are glued together. In the third stage, the operator manually removes excess paper that does not contain an image, which can take a lot of time for complex models.

As you already understand, quite a lot of waste is generated during the work: if the size of a given section of the model is much smaller than A4 or Letter, then the rest of the sheet will go into the trash; multiply by the number of sections and imagine how much paper will be thrown away.

The models turn out to be very impressive and quite durable, and their cost seems cheap - the paper is cheap!

But you will also need glue to join the layers (about $70 for 600 ml), and cartridges with dyes of standard CMYK colors (about $700 for a set of 4 cartridges of 320 ml or $195 for each cartridge separately), which, according to the manufacturer, enough for an average of 48 models. It turns out not so cheap, and the price of the device itself is even more impressive: in the West, prices starting from $47,600 are mentioned, and in Russian market offers even start from two million rubles.

There is also a natural limitation on the layer thickness, equal to the thickness of a sheet of paper. This is very clearly visible in the following model:

Using Mcor IRIS as an example, we list the main advantages and disadvantages, many of which are also inherent in other printers based on LOM technology.

• possibility of full-color printing with high resolution along the X and Y axes;
• availability and relative cheapness of the main consumable material - paper;
• you can create quite large models;
• for models with overhanging or horizontally protruding elements, the formation of supporting structures is not required.

• an extremely limited range of materials for creating models (in Mcor IRIS - only paper), and hence restrictions on the strength and other properties of the created samples;
• the thickness of the layer entirely depends on the thickness of the sheet material used, which is why the model sometimes turns out to be rough, and mechanical processing for smoothing is not always possible, since it can lead to delamination;
• the presence of a considerable amount of waste, and if the horizontal projections of the model are much smaller than an A4/Letter sheet, then a lot of waste is generated; This can be avoided by simultaneous production of several small samples;
• finishing processing associated with the removal of excess material is always required, it can only be simpler or more complex depending on the properties of the model; moreover, if the model has cavities with limited access, then it may simply be impossible to remove unnecessary things from them.

Since we mentioned full-color printing, which, although implemented in LOM technology, is still based on conventional 2D printing, we cannot help but talk about three-dimensional printing from gypsum composite.

3D Printing (3DP, 3D printing)

As in SLS, the basis for the future object is powder (gypsum composite), only it is not sintered, but glued together layer by layer by introducing a binder.

To build the next layer of the model, powder is applied and leveled over the entire area of ​​the working table with a roller, into which liquid glue is injected using a print head resembling an inkjet, according to the shape of a given section of the model. By the way: there is mention that the heads are being developed by Hewlett-Packard. Then the table with the already created layers is lowered and the process is repeated the required number of times, and at the end it is heated to speed up the drying of the adhesive composition. After this, excess powder that remains unbound is removed: mostly automatically, returning to the hopper for subsequent work, and from hard-to-reach places - with a stream of air (a cleaning station can be built into expensive models) or with a brush.

But in the resulting model, pores remain - the space between the powder particles, and the surface turns out to be rough. To impart the desired properties (smoothness, strength, low hygroscopicity), it must be treated with a special fixing compound. It can be a solution of Epsom salts (magnesium sulfate heptahydrate), wax, paraffin, cyanoacrylates and epoxy resin; Some of them can be applied by simple spraying or dipping, while for others special stations are used.

Where does full-color printing come from if the powder is the same? It’s very simple: dyes are introduced into a binder, and mixing them allows you to get from 64 to 390,000 shades. Moreover, some types of fixatives make the colors very bright.

This method is used in the ZPrinter series, produced by ZCorporation, which was acquired by 3D Systems in 2011, after which the series was called ProJet and a slightly different name. appearance. The series includes both color and monochrome printers with working chamber sizes up to 508x381x229 mm. The layer thickness can be set in steps from 0.089 to 0.125 mm, and the operating speed can reach 2700 cm³/hour.

The youngest model in the series, the ProJet 160 printer (ZPrinter 150), is sold in Russia at a price of over 700 thousand rubles, has a working chamber of 236 × 185 × 127 mm, the only possible layer thickness is 0.1 mm. The dimensions of the device are 740×790×1400 mm and weighs 165 kg.

The resolution provided by this device is 300 dpi along the X axis, 450 dpi along the Y axis and 250 dpi (i.e. 0.1 mm) along the Z axis. The print head has 304 nozzles and the operating speed is 870 cm³/hour. Since a white composite gypsum material is used, the models turn out white; There is no color printing option. An eight-kilogram bucket of powder costs about $1000, and a set of 2x1 liters of transparent binding liquid costs $600.

The cheapest color printer in the series, ProJet 260C (ZPrinter 250), will cost about 1.2–1.3 million rubles. Its parameters are approximately the same as those of the ProJet 160, and the number of available colors is limited to 64. The price of the youngest of the full-color printers, ProJet 460Plus (ZPrinter 450), is almost twice as high.

• allows you to create very complex models without supporting structures;
• possibility of full-color printing with high resolution.

• extremely limited amount of materials suitable for use;
• in some cases finishing treatment is required, especially when a rough surface cannot be tolerated;
• low strength of the resulting samples even after treatment with a fixing composition.

Now let's move on to the technology that Lately has become the most common, and we will consider it in more detail, since in subsequent reviews we will deal with printers based on this particular technology.

Layer-by-layer deposition (Fusing Deposition Modeling, FDM)

As in all other technologies we have considered, a model in FDM printing is created layer by layer. To produce the next layer, the thermoplastic material is heated in the print head to a semi-liquid state and extruded in the form of a thread through a nozzle with a small diameter hole, settling on the surface of the working table (for the first layer) or on the previous layer, connecting with it. The head moves in a horizontal plane and gradually “draws” the desired layer - contours and filling between them, after which a vertical movement occurs (most often by lowering the table, but there are models in which the head is raised) by the thickness of the layer and the process is repeated until the model will not be built completely.

Various plastics are most often used as consumables, although there are also models that allow you to work with other materials - tin, metal alloys with low melting points and even chocolate.

The disadvantages inherent in this technique are obvious:

• low operating speed (but, in fact, other technologies cannot boast of very high speed: building large and complex models requires many hours and even tens of hours);
• low resolution both horizontally and vertically, which leads to more or less noticeable layering of the surface of the manufactured model;
• problems with fixing the model on the desktop (the first layer should stick to the surface of the platform, but so that the finished model can be removed); They are trying to solve them in different ways - by heating the desktop, applying various coatings to it, but it is not possible to completely and always avoid it;
• overhanging elements require the creation of supporting structures that subsequently have to be removed, but even so, some models simply cannot be made on an FDM printer in one cycle, and they have to be broken into parts and then connected by gluing or other means.

Thus, many FDM samples will require more or less complex finishing that is difficult or impossible to mechanize and is therefore largely done by hand.

There are also less obvious disadvantages, for example, the dependence of strength on the direction in which the force is applied. Thus, it is possible to make a sample sufficiently strong for compression in the direction perpendicular to the arrangement of the layers, but for torsion it will be much less strong: rupture along the boundary of the layers is possible.

Another point is, to one degree or another, inherent in any technology associated with heating: this is heat shrinking, which leads to a change in the size of the sample after cooling. Of course, a lot depends on the properties of the material used, but sometimes you cannot come to terms with changes of even a few tenths of a percent.

Further: the technology may seem waste-free only at first glance. And we’re not just talking about supporting structures in complex models; a lot of plastic is wasted even by an experienced operator when selecting the optimal printing mode for a particular model.

Why, with so many problems, has this technology become so popular now?

The main and determining reason is the price of both the printers themselves and the consumables for them. The first important impetus in the process of promoting FDM printers “to the masses” was the expiration of patents in 2009, as a result of which over five years the prices for such printers decreased by more than an order of magnitude, and if we consider the extremes (the most expensive before 2009 and the cheapest today), then by two orders of magnitude: the price of the cheapest Chinese-made printers today is only 300–400 dollars - however, most likely the buyer will be instantly disappointed in them. More decent entry-level printers now have prices closer to $1200–1500.

The second important factor was the emergence of the project RepRap, or Replicating Rapid Prototyper - a self-replicating rapid prototyping mechanism. Self-reproduction concerns the production on an already made printer of parts for another similar printer - of course, not all of them, but only those that can be created within the framework of this technology; everything else has to be purchased. And it was not an end in itself of the project: main task was the creation of the cheapest possible printer models, accessible even to private enthusiasts who are not burdened with excess money, but want to try their hand at 3D printing. Moreover, not all prototypes created within RepRap were and are self-reproducing (in any significant part of all details).

We won't engage detailed description stages of the formation of the RepRap project, analysis of the advantages and disadvantages of such prototypes as Darwin, Mendel, Prusa Mendel, Huxley. The topic is too broad to be covered in this review, and we present these names only as keywords for searching for information, of which there is a lot on the Internet.

Of course, printers created in this way are most often far from perfect, even within the framework of FDM technology, but they allow you to create a fully functional device with minimal financial costs. It should be noted: today it is not at all necessary to look for the owner of the printer in order to print possible parts, and run around the shops in search of the rest; complete kits are offered for self-assembly of the printer, the so-called DIY kits (from “Do It Yourself” - do it yourself), which allow you to significantly save money and avoid unnecessary legwork and hassle, and also contain detailed instructions on assembly. But there is also room for those who do not want to be confined to ready-made designs and want to add something of their own to them: there are a lot of offers for any individual components for such printers.

Another one positive side development of the RepRap project - the emergence and improvement of various software for working with such 3D printers, which is freely distributed. This is an important difference from devices produced by famous manufacturers, which work only with their own software.

In principle, the project is not limited to FDM technology, but for now it is the most accessible one, just as the most accessible material is plastic filament, which is used in the vast majority of printers created on the basis of RepRap developments.

The widespread use of FDM printers has led to an increase in demand for consumables for them; supply could not help but follow demand, and the same thing happened as with the printers themselves: prices collapsed. If on old Internet pages devoted to FDM technologies there are references to prices at the level of 2-3 and even more than hundreds of euros per kilogram of plastic thread, now everywhere we are talking about tens of euros, and only for new materials with unusual properties the price can reach hundreds of dollars or euros per kilogram. True, if previously they sold mainly “branded” materials, now they often offer threads of unknown origin and uncertain quality, but this inevitably accompanies popularity.

Besides the price, FDM printers have other advantages related to the capabilities of the technology. Thus, it is very easy to equip the printer with a second print head, which can supply filament from easily removable material to create supports in complex models. By adding dye when making plastic thread, you can get different, very bright colors.

And the thread material itself can have very different properties, so let’s briefly consider the most common types.

The plastic thread can be of two standard diameters: 1.75 and 3 mm. Naturally, they are not interchangeable, and the choice of the desired diameter should be clarified according to the printer specifications. Plastic is supplied on spools and is measured not by length, but by weight. For FDM printers from some manufacturers (for example, CubeX from 3D Systems), you need to buy not spools, but special cartridges with filament, which are much more expensive per kilogram, but the manufacturer guarantees the quality of the material - in a word, everything is exactly the same as in conventional printers : “original” and “compatible” consumables.

For each type of material, the operating temperature to which the material in the print head must be heated, and the temperature of heating the working table (platform) for better adhesion of the first layer must be known. These values ​​are not always the same for any sample of thread made from the same type of material, so we provide an approximate range; In theory, the optimal temperatures should be indicated on the reel label or in accompanying document, but this does not always happen, and they often have to be selected experimentally.

The main materials for FDM printers are ABS and PLA plastics.

ABS(acrylonitrile butadiene styrene, ABS) is an impact-resistant technical thermoplastic resin based on a copolymer of acrylonitrile with butadiene and styrene. The raw material for its production is oil. This plastic is opaque and can be easily painted in different colors.

Advantages of ABS:

• durability,
• impact resistance and relative elasticity,
• non-toxic,
• moisture and oil resistance,
• resistance to alkalis and acids,
• wide range of operating temperatures: from −40 °C to +90 °C, for modified grades up to 103–113 °C.

The advantages include low cost, solubility in acetone (which allows you not only to glue ABS parts, but also to smooth out uneven surfaces with acetone). ABS is more rigid than PLA and therefore retains its shape under heavy loads.

The following disadvantages should be mentioned:

• incompatibility with food products, especially hot, because under certain conditions ( high temperature) may release hydrogen cyanide,
• instability to ultraviolet radiation(i.e. does not like direct sunlight),
• Heat shrinkage is noticeably higher than that of PLA,
• more brittle than PLA.

The operating temperature is higher than that of PLA and is in the range of 210–270 °C. There is a slight odor when working with ABS filament. In addition, for better adhesion of the first layer of the model to the work table, the table must be heated to approximately 110 degrees.

About the price: there are mentions of $30–40 per kilogram reel. In reality, prices in Russia start from 1,500 (small wholesale) to 2,000 or more (retail) rubles per kilogram, if we are talking about Chinese manufacturers. ABS thread from well-known companies, made in the USA, can be one and a half to two times more expensive.

PLA(polylactide, PLA) is a biodegradable, biocompatible polyester, the monomer of which is lactic acid. The raw materials for production are renewable resources - for example, corn or sugar cane, so the material is non-toxic and can be used to produce environmentally friendly packaging and disposable tableware, as well as in medicine and personal care products.

Let us note right away: biodegradability is not at all synonymous with extreme fragility; products made from PLA are quite viable.

Advantages:

• low coefficient of friction, making it suitable for the manufacture of plain bearings,
• low heat shrinkage, especially compared to ABS,
• less brittle and more tough than ABS: under the same loads, it is more likely to bend than break.

The operating temperature is lower than that of ABS: about 180–190 °C. Heating the desktop is not necessary, but it is still advisable to heat the table to 50–60 °C.

Disadvantages: we have already mentioned one of them - less durability than ABS. In addition, PLA is more hygroscopic, and even during storage it requires compliance with the humidity regime, otherwise the material may begin to delaminate and bubbles may appear in it, which will lead to defects in the manufacture of the model. In addition, PLA is often slightly more expensive than ABS, although the price greatly depends on the manufacturer and seller.

Acetone has virtually no effect on PLA; it has to be glued and treated with dichloroethane, chloroform or other chlorinated hydrocarbons, which requires increased safety measures during operation (but, of course, acetone is not a gift in this regard).

Other materials for FDM printing are much less common.

HIPS(High-impact Polystyrene, impact-resistant polystyrene) - the material is opaque, rigid, hard, resistant to impact, frost and temperature changes. It dissolves in limonene, a natural solvent extracted from citrus fruits, and can therefore be used to create support structures that do not have to be removed mechanically.

The operating temperature is about 230 °C, the price is 30–50% higher than ABS.

Nylon lightweight, flexible, chemical resistant. Parts made from it have very low surface friction.

The operating temperature is higher than that of PLA: about 240–250 °C. True, no vapors or odors are released. Nylon filament costs twice as much as PLA or ABS.

PC(Polycarbonate, polycarbonate) is a fairly hard polymer that retains its properties in the temperature range from −40 °C to 120 °C. It has high light transmittance and is often used as a glass substitute, and since it also has a lower specific gravity and a higher refractive index, it is ideal for the production of lenses. Complete biological inertness allows even contact lenses to be made from it. In addition, compact discs are made from it.

Printing temperature 260–300 °C. Few filaments are produced for FDM printing so far, so the price is three times higher than ABS.

Has similar optical properties PETT(Polyethylene terephthalate, polyethylene terephthalate). Models made from it are very durable, since the layers of molten material are perfectly glued together. The operating temperature is 210–225 °C, it is advisable to heat the table to 50–80 °C. The price is about 4500–5000 rubles per kilogram.

Under the abbreviation PVA(PVA) two types of material can be hidden: polyvinyl acetate (PVAc) and polyvinyl alcohol (PVAl). According to the chemical formula, they are quite similar, only polyvinyl alcohol lacks acetate groups, and their properties also coincide - in many ways, but not in everything. Unfortunately, sellers often simply indicate “PVA” without making any distinction, so we can only give a generalized approximate price: 4,500–5,000 rubles per kilogram of thread.

Polyvinyl alcohol PVAl requires an operating temperature of about 180–200 °C; further increase is undesirable - pyrolysis (thermal decomposition) may begin. In addition, the material is very hygroscopic; it actively absorbs moisture from the air, which creates problems both during storage and during printing, especially if the filament diameter is 1.75 mm. On the other hand, this same property is very useful: supports made of PVAl dissolve in cold water.

Polyvinyl acetate PVAc well known to everyone as component PVA glue, which is an aqueous emulsion of this substance. It requires a slightly lower operating temperature: 160–170 degrees. It is also highly soluble in water.

New materials with original properties appear all the time. True, the price for them at first can be very high.

For example, elastomer NinjaFlex allows you to create elastic products. The price is about 7500–8000 rubles per kilogram, the working temperature is 210–225 °C, the table temperature can be room temperature or slightly elevated, up to 35–40 °C.

Recently appeared material Laywoo-D3 It is interesting primarily because products made from it resemble wood in texture and even smell like wood. The fact is that it is made on the basis of small particles of wood and a binding polymer. Operating temperatures can be in the range of 175–250 °C; heating the table is not required. Moreover, the color after hardening will depend on the selected temperature: the higher it is, the darker it is. By changing the temperature during printing, you can even get a semblance of annual rings, like on natural wood. Of course, the price for this material is considerable - about 10 thousand rubles per kilogram.

Other exotic material Laybrick, contains mineral fillers and allows you to imitate sandstone products. The operating temperature is in the range of 165–210 °C; this time, with increasing temperature, a rougher surface can be obtained to enhance the simulation effect. It also does not require heating the bed, but after printing you should wait a few hours for the model to completely harden before removing it. The price is the same 10 thousand rubles per kilogram.

Of course, all the above prices are just a guideline: they can change both over time and from seller to seller, especially if you buy not in Russia, but order abroad.

Since our review is intended mainly for those who have recently become interested in 3D printing and do not yet have their own experience in this field, we note: it is best to start with the “young fighter course”, and we will even recommend (you can download the course program and find contact coordinates). In addition to the story about theoretical foundations, each “cadet” is given the opportunity to work on a very good FDM printer under the guidance of knowledgeable specialists. Of course, the courses are commercial, that is, they are paid, but the money spent will quickly pay off, since you will gain knowledge on how to avoid the most common mistakes and practical experience, albeit small.

This concludes our review to soon move on to other aspects of 3D printing and specific printer models.

Friends, a short introduction!
Before reading the news, let me invite you to the largest community of 3D printer owners. Yes, yes, it already exists, on the pages of our project!

Today, the consumer 3D printer market can offer only two types of 3D printing technologies. These are fused deposition modeling () and stereolithography (). Fused fusion modeling technology uses molten plastic to create 3D objects by extruding it onto a print platform, layer by layer, until the entire object is complete. The second technology, stereolithography, uses either a laser or a light projector to cure liquid polymers, layer by layer, until the final result is achieved.

Over the past few years that 3D printers have been available for home use, these two technologies have been the only ones widely available among printers on the market.

A new company, Orange Maker™, hopes to change that. Today they announced that they have developed a new 3D printer, the Helios One, that incorporates a new patent-pending technology called heliolithography (HL).

“Heliolithography uses ultraviolet light directed with ultra-high precision to polymerize liquid resin into solid plastic,” explained Orange Maker co-founder Doug Farber. “Heliolithography, in contrast to stereolithography technology, is a continuous printing process, i.e. without stopping between layers, allowing you to print 100% of the time.”

According to Orange Maker, this new technology has a number of advantages over traditional 3D printing technologies, including:

• Continuous and efficient construction process
• Large, scalable build area
• Ultra high resolution
• Reliable printing technology that delivers a much higher success rate than other consumer-grade technologies.

The printer will be positioned on the market for professional consumers, and will be sold at an affordable price. of this market price, although the official price has not yet been announced. The Orange Maker company also announced that the printer will be created for “creative people of a wide variety of professions who are looking for reliable technology High Quality: various designers, engineers, artists, doctors, etc."

Orange Maker believes that heliolithography technology will allow them to produce 3D printers with significantly expanded limits on print size, resolution and the range of possible materials.

This project actually started back in 2011, when the future co-founders of this company, Kurt Dudley and Farber Doug, began collaborating. Now, 3 years later, they are finally ready to announce their new technology after filing for patents.

“Simply put, we found a way to optimize efficiency, design and material savings in 3D printing technology, which to this day is significantly limited in aspects such as print sizes, print speeds and material availability,” explained co-founder Kurt Dudley. “We have achieved the ideal of greatly expanding functionality while achieving elegance and simplicity through design and engineering.”

The Helios One 3D printer is scheduled to be released in 2015, when it will be available directly from the manufacturer Orange Maker, as well as through select third-party suppliers. More models of this printer will be released soon after the first model is launched into the market. We'll be looking forward to hearing more about how this printer is designed and how it functions, as well as what its price will be at launch. Follow our publications and you will be among the first to know these details.

Share your thoughts about this new technology in the comments to this article. Do you think heliolithography can change the current landscape of the consumer printer market?