Additive technologies in the Russian industry. additive method

Additive technologies are actively used in power engineering, instrumentation, aviation industry, space industry, where there is a high need for products of complex geometry.In Russia, many enterprises have already become acquainted with additive technologies. We bring to your attention material from the almanac"Production Management", which describes several examples of the effective implementation of 3D printing.

Additive technologies have opened up the possibility of manufacturing parts of any complexity and geometry without technological restrictions. The part geometry can be changed at the design and testing stage.

Preparation of files for printing is carried out on computers with standard software, STL files are accepted for work. This is a widely used format for storing three-dimensional objects for stereolithographic 3D printers today. Investments in the project amounted to about 60 million rubles.

Alexander Zdanevich, IT Director, NPK United Wagon Company: “Additive printing technologies are progressing, and, most likely, in the near future they will change the face of a number of industries. This mainly concerns enterprises that produce piece goods for a specific order. With mass production, the situation is more complicated, although different types of 3D printers are already being used in this area.

There are many technologies for bulk synthesis. One of the promising for industrial implementation is. The process can be divided into two stages. At the first stage, a construction layer is formed in the form of a liquid photopolymer evenly distributed over the surface of the working platform. Then there is a selective curing of sections of this layer in accordance with the current section of the 3D model built on the computer.

With regard to railway engineering, this technology can be used at the stage of preparation of foundry production, in particular, in the production of a set of foundry equipment. The same set of tooling, unique for each casting, is used for thousands of production cycles of the corresponding casting molds.

The quality of the final product directly depends on the accuracy of all the parameters provided for by the designers during the manufacturing process of the tooling kit. The traditional method of manufacturing a set of tooling by mechanical processing of materials (metal, plastic, and sometimes wood) is very laborious and lengthy (sometimes takes up to several months), while being sensitive to errors.

The original of this article: Additive technologies: the possibilities and prospects of 3D printing. "Manufacturing control. Digital Production”, April 2017. Published in abbreviated form.

A master is only as good as his tools. So a 3d printer is only as good as the . We have all heard about additive manufacturing (AM), but for this technology to go from quick creation prototypes to mass production, it has many obstacles to overcome.

Undoubtedly, one of the biggest barriers to making 3D printing a manufacturing process, are the constraints associated with the materials. We have come a long way from the days when only proprietary plastic filaments were used. In recent years, AM using metal has developed rapidly, and the trend of open platforms for 3D printing resins is encouraging many players, such as DuPont, to create new material applications for the additive market.

The State of the Additive Manufacturing Industry

You can not even talk about the growth of the AP market in the last ten years. Moreover, current forecasts suggest that the 3D printing market will continue to overtake traditional manufacturing technologies such as injection molding and CNC machining. The outlook for metal-based AP is even more optimistic, which explains why companies such as Vulcan Laboratories, which previously concentrated on polymer-based AP, have begun investing in metal applications.

The noticeable changes in the AP industry are easier to perceive by looking at how far the industry has come in such a short time. “In 2008, 3D printing was done by a handful of companies, producing a couple of printers a year for research purposes. But now the entire industry is evolving at a pace that is vastly different from what it was 10 years ago,” says John Kawola, president of Ultimaker .

Gordon Styles, president and founder of Star Rapid, noted the changes to the AP materials. “Ten years ago, I wouldn't have imagined that you could print with materials that are highly durable, chemically resistant, and reflect heat,” he says. — It was until recently, but the Markforged startup is doing just that. Instead of larger corporations offering this technology, Markforged was the first to create parts with onyx, and even uses filament from Kevlar, carbon fiber and HSHT glass fiber.”

As Kavola and Stiles' words show, the contrast between 2008 and 2018 in the 3D printing industry is quite noticeable. In ten years, we've gone from a few companies to hundreds, and we've seen desktop 3D printing opportunities explode at the same time as prices plummet. And we have gone from theoretical discussions about the use of metal and other materials in 3D printing, to the additive manufacturing of parts for the aerospace industry.

Spools of thread, wrapped in cellophane to protect against moisture

In comparison, while Motorola's RAZR V3 phone was the most popular phone in its day, in 2008 we already had the iPhone, Facebook, Twitter, and more. In terms of manufacturing technology, 2008 was the year that the MTConnect open communication standard was proposed at IMTS.

Other innovations at IMTS 2008 were multifunctional machines, plastics and composites machining. All of these technologies have made progress over the past decade, but none of them compare to the explosive growth of AP that we have seen and continue to see today.

Additive Industry Materials

According to the Wohlers Report 2017, the market for AP materials has grown by 17 percent since 2016. This is slower than the growth of the polymer AP market as a whole, which had a compound annual growth (CAGR) of 29 percent from 2010 to 2017. This should come as no surprise: the materials market has not yet matured, and it is much easier to release a new 3D printer than it is to develop new material for print.

Diversity of materials is still a problem in AP, although not as pronounced as ten years ago. “If you go back to 2008, almost all companies used proprietary plastics as a material,” Kavola explains. - For a supplier, when the consumer could only buy from you, the income was high. But if we take the materials with which we worked at that time, then there may have been dozens of them, and not hundreds, as they are now.”

The use of proprietary materials is good way maintain a monopoly, but it holds back the development of new materials. If the client has no choice and must only buy from you, then it doesn't matter if your competitor offers another material with better features, because the barrier to the client's transition to it - buying a new 3d printer - is too high.

This market segmentation also discourages innovation from material suppliers. If you're DuPont, it's much more profitable to develop nylon-based 3D printing materials that can be used on a variety of printers than it is to create a custom formula for each brand.

Fortunately, the market for AM materials has become much more open in recent years, as Stiles explains: “Today, we see that most printer manufacturers are open to the development and use of raw materials from buyers and third-party suppliers. This may be due to the number of competitors with low prices and the fact that the development and testing of new materials are costly and can have a very narrow niche of application. This is especially true for metal alloys."

“Therefore, the 3D printing industry — including companies like Ultimaker and HP — has moved towards open material platforms in recent years,” Kavola says. “It opened the door to the big materials companies around the world—DuPont, Dow, Owens Corning, Mitsubishi, DSM, and many more. I think it's playing big role to push 3D printing in the direction of manufacturing as the best in the world of resin materials begin to use materials used in injection molding and adapt them for 3D printing.”

But when using AP in production, the problem of material certification remains. “Checking the materials for the AP and proving that the products obtained are no worse, if not better than the products obtained traditional methods, is a major barrier to the use of AP in manufacturing,” Stiles says. “This requires money and time. In a production environment, it is necessary to prove the ability to achieve the same quality for different suppliers, as well as to distribute and increase their number.

“The high requirements for consistent quality for raw materials are difficult to meet with a large supply base, not to mention differences in production technology and raw material sources used by suppliers. All these factors must be taken into account,” he adds.

The scope for materials for additive manufacturing is definitely on the rise as large material suppliers step in, but what materials are truly suitable for manufacturing applications today?

Types of materials for AP

While there are many materials that can be used in AM—including sand, glass, ceramics, and even chocolate—this article only focuses on the two categories of materials that play the largest role in manufacturing applications: polymers (such as thermoplastics) and metals.

Metal materials for 3d printing

The market for AM metal materials has grown even faster than the entire AM market, and the reason for this is the materials. Unlike polymer 3D printers, which require the development of an entirely new material industry, metal 3D printers work with wire or (more commonly) metal powder from existing suppliers.

Of course, if you want to produce high quality metal parts, you need to use a powder specially designed for AM, i.e., in which particle size uniformity is observed. However, the use of the same materials for metal plating and 3D printing has contributed to the development of the powder industry. This means that it is possible to manufacture metal parts using the AM technology from the same material from which they were made before.

And in itself, AM provides new opportunities for materials that were not used in traditional production. For example, some metal 3d printing methods allow you to apply layers various metals- aluminum, tantalum and nickel - in the manufacture of one part. On the other hand, the 3D printing process also introduces new problems and error sources, including porosity, residual stresses, and deformations.

But in general, if the metal behaves well in welding or casting, it is also suitable for AM. As noted above, there is already a wide range of metals and alloys that can be used in 3D printing, either in powder form or wire form. These include:

• Aluminum
• Cobalt
• Inconel
• Nickel
• Precious metals (gold, silver, platinum)
• Stainless steel
• Tantalum
• Titanium
• Tool steel
• Tungsten.

Let's take a closer look at three metals from this list.

Additive manufacturing with titanium

Titanium is one of the most popular materials for 3D printing in manufacturing, especially in aerospace and medical applications. It combines the lightness of aluminum with the strength of steel, and it is non-toxic. However, these advantages are countered by the relatively high cost of titanium. Therefore, reducing waste makes AM an attractive option for producing titanium parts.

Titanium powder is highly flammable and explodes on contact with water at temperatures exceeding 700°C. For this reason, 3d printing with titanium powder is done in vacuum or argon chambers. It is also possible to 3D print using electron beam melting (EBM) titanium wire, eliminating the risk of an explosive reaction.

The two most common titanium alloys used in AM are 6Al-4V and 6Al-4V ELI.

3d printing with aluminum

Aluminium, a lightweight and versatile metal, can be used for 3D printing of aerospace components and racing car parts. Although it does not have the strength of steel, aluminum is much lighter than steel and more resistant to corrosion. They are also more expensive than steel, although not as much as titanium.

The main advantage of using aluminum in 3D printing is the ability to produce parts with small features and thin walls (up to 50 microns). Aluminum parts made by AM methods have a more textured, matte surface, in contrast to the polished surface in the production of aluminum parts on machine tools

A common aluminum alloy for 3d printing is AlSi10Mg.

Additive manufacturing in stainless steel

Compared to aluminum, titanium, and most of the other metals on this list, stainless steel is a more affordable option. It can be used to 3d print waterproof parts with high strength and density, and used in extreme environments such as jet engines aircraft and missiles. Studies have been carried out on the applicability of 316L stainless steel for the production of cases nuclear reactors with the help of AP. Although 316L is generally non-heat treatable, a Renishaw report suggests that the AM process generates stronger alloys than metal forging, producing tensile forces in excess of 600 MPa. Stainless steel parts are 3D printed either by direct metal deposition or by using a composite material with a binder. Parts can be plated with other metals to change appearance or surface properties.

Common stainless steel alloys used in AP are 17-4PH, 15-5-PH, ASM 316L and 304L.

Thermoplastic materials for 3d printing

The market for materials for thermoplastic or polymeric AM has evolved over several decades, and with the emerging trend towards open platforms for 3D printing materials, it has become more stable. As Kavola says: “OEMs buy their injection molding materials from large companies producing plastics. If these companies also produce filament or powder for 3D printing, then it is possible to use them in 3D printers at the prototyping stage, and then use the same materials for injection molding. The idea is relatively new, and only emerged in recent years.”

There are several advantages to using the same materials for 3D printing and injection molding. Among them is the certainty of using the same materials throughout the entire process, from prototypes to production. There are also less obvious advantages, such as the absence of additional certification of materials, which increases the time for their acceptance.

“Injection molding and 3D printing processes for making the same part are different, but if the same material is used, then the company benefits from adopting AM technologies,” Kavola says.

Stiles highlights the emergence of one popular material: “This year we saw the emergence of PEEK, a colorless, organic, thermoplastic polymer for a variety of manufacturing systems,” he says. - PEEK is very popular in the automotive, medical, aerospace and chemical industries. It is impact resistant (hard), strong, durable, has a melting point in excess of 300°C, and is FDA approved for use in food contact.”

The list of polymer materials for 3d printing is much longer list metals, but among the most popular materials are the following:

• Acetal
• acrylic fiber
• Acrylonitrile butadiene styrene (ABS)
• Acrylonitrile styrene acrylate (ASA)
• High impact polystyrene (HIPS)
• Nylon
• Polycarbonate (PC)
• Polyetheretherketone (PEEK)
• Polyethylene terephthalate (PET)
• Polyethylene terephthalate trimethylene (PETT)
• Glycol-modified polyethylene terephthalate (PET-G)
• Polylactide (PLA)
• Polypropylene (PP)
• Polyvinyl alcohol (PVA)
• Thermoplastic elastomer (TPE)
• Polyetherimide ULTEM

As in the case of metals, we will consider in detail three materials from this list.

AP with Acrylonitrile butadiene styrene (ABS)

Until now, ABS is a very popular material for 3D printing. Although PLA is generally more popular, it is almost always better to use ABS for manufacturing due to its strength, durability and low cost. For 3D printer applications, ABS needs to be heated to a relatively high temperature of 230-250°C, and so it requires the base of the printer to be heated to ensure proper cooling and prevent warping.

ABS parts are produced using fusion bonding (FDM), layer-by-layer bonding, stereolithography (SLA) or photopolymer printing techniques. The main disadvantage of ABS is its toxicity, which releases poisonous fumes when it reaches its melting point. 3D printed ABS parts are often used for end product casting or tooling applications.

3d printing with nylon

Nylon (polyamide) is a synthetic polymer. It is stronger than ABS, although more expensive. It is flexible and exhibits excellent material memory. Layer-by-layer bonding of 3D printed parts also brings nylon to an above-average level.

The sensitivity of nylon to moisture necessitates its use in AP either under vacuum or at high temperature. It must be stored in airtight containers. Some nylon parts can compress, making it a less accurate material than ABS.

Popular grades of nylon for AP are Taulman 618, Taulman 645 and Bridge Nylon.

Additive manufacturing with polycarbonate (PC)

Polycarbonate (trademark Lexan), is a lightweight and dense material with excellent tensile strength. Its transparency allows it to be used for a variety of applications, even in the production of sunglasses. Carbon-reinforced PC can be used for intake manifolds and other high temperature parts.

PC dissolves in dichloromethane, and melts at 260-300°C, which is pretty high for 3d printing. Although transparent, PC can be tinted if necessary. Like ABS, it requires the base of the printer to be heated to ensure bonding and reduce warping.

Materials for 3d printing

Despite all the progress, 3D printing remains more of a niche technology than a mainstream in manufacturing. Kavola explains the current place of AP in the sector as a whole by looking at two extremes of the manufacturing spectrum;

“One extreme is producing Lego pieces at half a cent each,” he says. “You will never be able to compete here using 3D printing, at least not in my lifetime. The other extreme is the use of 3D printing in dentistry, where everything is done in a single copy. Therefore, the best opportunity for 3D printing in manufacturing is where 100 to 1000 parts are produced.”

When it comes to materials, Stiles points out one of the things to consider. “People need to know the cost of raw materials and production,” he says. “Many simply do not understand how costly the AP process can be. Understanding costs can help you make an informed decision about 3D printing a traditional technology such as injection molding or CNC machining.”

The use of new technologies is the main trend recent years in any area industrial production. Every enterprise in Russia and the world strives to create cheaper, more reliable and high-quality products, using the most advanced methods and materials. Usage additive technologies- one of brightest examples how new developments and equipment can significantly improve traditional production.

What is additive technologies?

Additive manufacturing technologies make it possible to produce any product in layers based on a 3D computer model. This process of creating an object is also referred to as "growing" due to the gradualness of the production. If in traditional production at the beginning we have a workpiece, from which we cut off everything superfluous in bulk, or we deform it, then in the case of additive technologies, a new product is built from nothing (or rather, from an amorphous consumable material). Depending on the technology, an object can be built from the bottom up or vice versa, get different properties.

The general scheme of additive manufacturing can be represented as the following sequence:

The first additive manufacturing systems worked primarily with polymeric materials. Today, 3D printers that represent additive manufacturing are able to work not only with them, but also with engineering plastics, composite powders, various types of metals, ceramics, sand. Additive technologies are actively used in mechanical engineering, industry, science, education, design, medicine, foundry and many other areas.

Illustrative examples of how additive technologies are used in industry - the experience of BMW and General Electric:

Advantages of additive technologies

• Improved properties of finished products. Due to the layered construction, products have a unique set of properties. For example, parts created on a metal 3D printer in terms of their mechanical behavior, density, residual stress and other properties are superior to analogues obtained by casting or machining.
• Great savings in raw materials. Additive technologies use almost the amount of material that is needed to produce your product. Whereas with traditional manufacturing methods, the loss of raw materials can be up to 80-85%.
• Possibility of manufacturing products with complex geometry. Equipment for additive technologies makes it possible to produce items that cannot be obtained in any other way. For example, a part within a part. Or very complex cooling systems based on mesh structures (this cannot be obtained either by casting or stamping).
• Mobility of production and acceleration of data exchange. No more drawings, measurements and bulky samples. At the heart of additive technologies is computer model future product that can be transferred in a matter of minutes to the other side of the world - and immediately begin production.

Schematically, the differences in traditional and additive manufacturing can be represented by the following diagram:

Additive manufacturing: technologies and materials

Additive manufacturing is the process of growing products on a 3D printer from a CAD model. This process is considered innovative and is opposed to the traditional ways of industrial production.

Today, the following additive manufacturing technologies can be distinguished:

• FDM(Fused deposition modeling) - layer-by-layer construction of a product from a molten plastic thread. It is the most widely used 3D printing method in the world and is used by millions of 3D printers, from the cheapest to industrial systems 3D printing. FDM printers work with various types plastics, the most popular and affordable of which is ABS. Plastic products are highly durable, flexible, and are great for product testing, prototyping, and ready-to-use objects. The world's largest manufacturer of plastic 3D printers is the American company Stratasys.
  .

• SLM(Selective laser melting) - selective laser melting of metal powders. The most common metal 3D printing method. Using this technology, it is possible to quickly produce metal products with complex geometries, which are superior in their qualities to foundry and rolling production. The main manufacturers of SLM printing systems are the German companies SLM Solutions and Realizer.
  .

• SLS(Selective laser sintering) - selective laser sintering of polymer powders. Using this technology, it is possible to obtain large products with various physical properties (increased strength, flexibility, heat resistance, etc.). The largest manufacturer of SLS printers is the American concern 3D Systems.
  .

• SLA(short for Stereolithography) - laser stereolithography, the curing of a liquid photopolymer material under the action of a laser. This additive digital manufacturing technology is focused on the manufacture of high-precision products with various properties. The largest manufacturer of SLA printers is the American concern 3D Systems.
  .

Rapid prototyping technologies should be placed in a separate category. These are 3D printing methods designed to obtain samples for visual evaluation, testing, or master models for creating molds.

• MJM(Multi-jet Modeling) - multi-jet modeling using photopolymer or wax material. This technology makes it possible to produce burnt or smelted master models for casting, as well as prototypes of various products. Used in 3D Systems ProJet series 3D printers.
• PolyJet- curing of liquid photopolymer under the influence of ultraviolet radiation. Used in the Objet line of 3D printers American company Stratasys. The technology is used to obtain prototypes and master models with smooth surfaces.
• CJP(Color jet printing) - layer-by-layer distribution of the adhesive on powder gypsum material. Gypsum 3D printing technology is used in the ProJet x60 series 3D printers (formerly called ZPrinter). To date, this is the only industrial technology for full-color 3D printing. With its help, bright colorful prototypes of products are made for testing and presentations, as well as various souvenirs, architectural models.

Additive technologies in Russia

Domestic enterprises every year more and more actively use 3D printing systems in production and scientific purposes. Additive manufacturing equipment, intelligently integrated into the production chain, allows not only to reduce costs and save time, but also to start performing more complex tasks.

Globatek.3D has been supplying the latest 3D printing and 3D scanning systems to Russia since 2010. The equipment installed by our specialists works in the largest universities (MGTU named after Bauman, MEPhI, MISIS, Privolzhsky, SSAU and others) and industrial enterprises, institutions of the military-industrial complex and the aerospace industry.

Report of the TV channel "Russia" on the use of SLM 280HL, installed by Globatek.3D specialists at the Samara State Aerospace University:

GLobatek.3D specialists help professionals from various fields to choose 3D equipment that will most effectively solve the problems facing the enterprise. If your company is considering purchasing additive manufacturing equipment, call +7 495 646-15-33 , and Globatek.3D consultants will help you with the choice.

Globatek.3D - 3D equipment for professionals.

The technological process does not stand still, every day there is an improvement in digital technologies, which allows the use of innovations in various fields human life. Additive technologies are among the most advanced and in demand all over the world.

Additive technologies - what is it?

Additive Manufacturing (from the word additivity - added) is a layer-by-layer build-up and synthesis of an object using computer 3d technologies. The invention belongs to Charles Hull, who in 1986 designed the first stereolithographic three-dimensional printer. What does the additive process of layer-by-layer creation of a model mean and how does it work? In modern industry, these are several different processes, as a result of which a 3d object is modeled:

• UV irradiation;
• extrusion;
• jet spraying;
• fusion;
• lamination.

Materials used in additive technologies:

• wax;
• gypsum powder;
• liquid photopolymers;
• metal powders;
• various kinds of polyamides;
• polystyrene.

Application of additive technologies

Technological progress contributes to the production of many useful things for everyday life, human health and safety, for example, additive technologies in aircraft manufacturing help to create more highly economical and lighter air transport, while its aerodynamic properties are fully preserved. This was made possible by applying the principles of bird wing bone structure to the design of aircraft wings. Other areas of application of additive technologies:

• construction;
• agricultural industry;
• mechanical engineering;
• shipbuilding;
• astronautics;
• medicine and pharmacology.

Additive 3d technologies

Dynamically developing rapidly additive 3d printing technologies are used in progressive industries. There are several innovative types of additive technologies:

1. FDM(Fused deposition modeling) - the product is formed in layers from a molten plastic thread.
2. CJP(ColorJet printing) is the only full-color 3d printing in the world with the principle of gluing powder consisting of gypsum.
3. SLS(Selective Laser Sintering) is a laser sintering technology that produces highly durable objects of any size.
4. MJM(MultiJet Modeling) multi-jet 3d modeling using photopolymers and wax.
5. SLA(Laser Stereolithography) - layer-by-layer hardening of a liquid polymer occurs with the help of a laser.

Additive technologies in mechanical engineering

Jim Corr, an American engineer, has been using additive manufacturing in mechanical engineering for 15 years. The Urbee project by Kor Ecologic is the creation of the first prototype of a 3d car with a speed of 112 km / h, its body and some parts are printed on a 3d printer. Another company Local Motors in November 2015 introduced a "smart and safe" car LMSD Swim - 75% of the parts of which are made using three-dimensional printing using ABS plastic and carbon fiber.

Additive technologies in construction

Additive manufacturing of buildings and various structures significantly reduces construction time. Construction 3D printing is trending all over the world. Experiments carried out on laser 3d printers for ordinary people look on the verge of fantastic. Additive 3D technologies - positive aspects in construction:

• saving time and financial costs (speed of construction in a matter of days, reducing the cost of logistics, consumables, hiring a large number personnel);
• implementation of any design solutions and complex geometric shapes(medieval castles, houses in the form of asteroids and galaxies);
• the ability to build houses with regard to seismic resistance in areas prone to earthquakes and hurricanes.

The most famous 3d buildings:

Additive technologies in medicine

In 2016, it became a breakthrough for medicine thanks to additive 3d technologies. The quality of medical services has increased significantly. The additive process has affected several areas of healthcare and this has reduced mortality among patients in need of quality and urgent medical services. Benefits of using additive 3D printing in medicine:

1. With the help of tomographic images, it became possible to accurately print an organ with pathology to study the subtleties and nuances of the upcoming operation.
2. Transplantation has come a long way. Additive technologies here solve several problems at once - moral and ethical and reducing waiting times, known fact that people wait for several years for donor organs, but sometimes the bill goes not for years, but for days and even hours. Transplantation of artificially grown human organs will soon become a reality.
3. Printing of sterile instruments. In the era of severe and incurable viral infections, disposable sterile instruments nullify infection during medical procedures.

Today, the following products of additive technologies are successfully used in medicine:

• artificially grown human skin(relevant for transplantation to people with high area burns);
• biocompatible bone and cartilage tissue;
• printing organs with an oncological process and studying the effect of drugs on tumors;
• dental implants, prostheses, crowns;
• individual hearing aids;
• orthopedic prostheses.

Additive technologies in pharmacology

With an abundance of modern medicines, it is important for a doctor to know what an additive effect in medicines is, the success of treatment depends on it. The cumulative effect of the drugs taken during treatment should be synergistic (mutually complementary and reinforcing), but this is not always the case. It all depends on individual intolerance, the state of the body. Additive technologies come to the rescue here too. 3D-printed Spritam tablets for epilepsy are already being tested, which contain information about the patient: gender, weight, age, liver condition, individual dosage.

Additive technologies in education

Additive technologies are already being actively introduced at school, if until recently schoolchildren studied 3d modeling in specialized computer programs, now it has already become possible to print the simulated image in volume. Students visually see their inventions, mistakes made and how the mechanism works. By 2018, the Ministry of Education plans to train additive technologies in educational institutions 3000 teachers.

Subtractive and additive methods for manufacturing boards, comparative characteristics.

AT subtractive methods (from Latin substratio - subtraction), a conductive pattern is formed by removing the foil from unprotected areas of the surface. To do this, a circuit pattern is applied to the copper foil of the dielectric, and unprotected sections of the foil are etched. The disadvantages of the subtractive chemical method include a significant consumption of copper and the presence of lateral etching of the elements of printed conductors, which reduces the adhesion of the foil to the base.

This shortcoming is devoid of additive (from lat. additio - addition) a method of manufacturing PCB, based on the selective deposition of chemical copper on a non-foiled dielectric. In this case, a dielectric is used with a catalyst introduced into its composition and an adhesive layer on the surface. The boards made by the additive method have a high resolution (conductors up to 0.1 mm wide), the production costs of such boards are reduced by 30% compared to subtractive methods, copper and etching chemicals are saved, and the environmental situation at enterprises is improved. However, the use of the additive method in mass production is limited by the low productivity of the chemical metallization process, the intense effect of electrolytes on the dielectric, and insufficient adhesion of conductors.

Additive method and semi-additive fabrication of DPP.

additive method

A non-foiled dielectric is used with a catalyst Pd:Sn = 1:3 introduced into it.

dielectric surface preparation (cleaning);

Application of the adhesive by immersing the board in a composition based on nitrile rubber 20-30 µm thick or ABS-2 polymer and pulling it out of the polymer solution at a speed of 20-100 mm/min, followed by drying at a temperature of 130-140 °C for 1.5- 2 h;

Drilling and cleaning holes in the board;

Application of a protective negative pattern of the circuit, which has increased resistance to the high-alkaline composition of the chemical copper plating bath;

Etching of dielectric surfaces open for copper deposition in a solution of fluoroborate or chromic acid to improve the adhesion of conductors to the substrate;

Chemical copper plating for 8-16 hours;

Removal of protective resist;

Applying a mask for soldering by screen printing;

Tinning of conductors and plated holes in the board.

The use of the additive method is limited by its low productivity, the difficulty of obtaining good adhesion of conductors to the base, and the intense effect of solutions on the dielectric.

At semi-additive method For the manufacture of DPP, a non-foiled dielectric without an introduced catalyst is used; therefore, the operations of sensitization and activation are mandatory. The process includes the following operations

 dielectric surface preparation and adhesive application;

Drilling and cleaning holes;

Sensitization and activation of the entire surface;

Chemical copper plating with a layer of 2-3 microns thick for screen printing and 4-6 microns for photo printing;

Creation of a protective drawing of the circuit;

Galvanic copper plating (copper strengthening);

Resist removal and etching;

Creation of non-plated holes;

Applying a mask for soldering and tinning printed conductors.