Modern high technology. Technologies for the production of composite materials Restoration of a diagonal pump wheel

Modern high technology. Technologies for the production of composite materials Restoration of a diagonal pump wheel
Modern high technology. Technologies for the production of composite materials Restoration of a diagonal pump wheel
25.11.2019

Composite materials are materials created from several components. They are mainly made from a plastic base, reinforcing filler, and some other substances. As a result, the composite is characterized by high strength, rigidity and many other useful properties.

Polymer composite technologies are methods for creating materials whose matrix is ​​a polymer. They have a huge number of types and species, which ensured their prevalence and popularity. The following types of ceramic polymers exist:

Fiberglass;
carbon fiber reinforced plastics;
boroplasty;
organoplastics;
polymers filled with powders;
text slabs.

Composite ceramic materials are used in a wide variety of areas, among which are the following:

Construction;
electrical engineering;
chemical industry;
road construction;
telecommunications;
aviation industry, etc.

The prevalence and popularity of composite technologies is associated with the many advantages of this method of manufacturing materials. It is worth paying attention to the following positive qualities:

Improved physicochemical characteristics;
quite low specific gravity;
resistance to corrosion, rotting or warping;
low toxicity when burning;
non-flammability or difficult flammability;
unique chemical resistance;
low coefficient of linear expansion due to the action of heat;
fairly wide temperature range of functionality;
high electrical insulating properties;
increased environmental cleanliness.

IN XXI century Composite materials based on ceramic polymers have become one of the quite popular substances used to solve various technological challenges in a wide variety of fields, both construction and engineering or other types of industries. This was achieved with the help of many advantages that distinguish composites from other types of materials popular until this time.

Restoring the diagonal pump wheel

Composite materials can also be used to restore the diagonal pump wheel. With a similar request for repair of the pumping device Wastewater Under the name KSB Sewatec, the enterprise MP Angarsky Vodokanal contacted Ceramet.

Over three years of operation, the pump's performance dropped to 70%, starting from the first day of operation. The repair included metal restoration, application of composite material, and dynamic balancing. Thus, due to the use of composite technologies, it was possible to extend the life of the pump and achieve cost savings of 4.5 times.

Features of the Ceramet material

Ceramet composite ceramic materials are designed to protect equipment, extending its service life and increasing its operating life. This significantly reduces downtime and the need to purchase additional spare parts.

The peculiarity of the Ceramet material is its fairly wide range of applications, which includes:

Repair pumping equipment;
renewal of augers;
improving the functionality of heat exchangers;
repair of pipelines, gutters, etc.

Thus, Ceramet composite material can be used for many different purposes, which is more advantageous than other equipment renewal methods.

1

The article presents the current state of technology for the production of products from composite materials, including information about the technologies used, software, equipment for creating matrices, equipment for creating composite products, equipment for monitoring product geometry and non-destructive testing.

composite materials

software

equipment for creating a matrix

1. Modern composite materials / ed. P. Krok and L. Browman; lane from English – M., 1978.

2. Construction and strength of fiberglass hulls and ship hulls. Foreign shipbuilding in 1965 – 1973 // Shipbuilding, 1973.

3. Frolov S.E. Methods for creating new macro-inhomogeneous composite materials and technological solutions for the manufacture of hull structures from them // Shipbuilding No. 3 2003, p. 55-59.

4. CAE – technologies in 2012: review of achievements and market analysis. – CAD/CAM/CAE Observer #4 (80) / 2013.

5. Interview with V.A. Seredka and A.Yu. Sofronov to the magazine CAD/CAM/CAE Observer #2 (78) / 2013.

6. Smart technologies for the aircraft industry. Increasing the competitiveness of domestic aircraft manufacturing enterprises using the example of joint projects of the Solver company and JSC VASO // CAD and Graphics, No. 1. 2011. P. 56-62.

7. Lukyanov N.P. Experience in using composite materials for the construction of PMO ships // Shipbuilding. No. 3. 2007. pp. 19-26.

A composite material is a material whose structure consists of several components with different physical and mechanical properties: metallic or non-metallic matrices with a given distribution of strengtheners in them, their combination gives the composite material new properties. According to the nature of the structure, composite materials are divided into fibrous materials, reinforced with continuous fibers and whiskers, dispersion-strengthened materials obtained by introducing dispersed particles of hardeners into the matrix, layered materials created by pressing or rolling dissimilar materials.

Today, composite materials are especially in demand in various industries. The first fiberglass ships were made in the second half of the 30s of the twentieth century. Since the 50s, fiberglass shipbuilding has become widespread in the world; a significant number of yachts, work and rescue boats and fishing vessels, landing craft, etc. have been built. One of the first applications of composite materials in aviation was the manufacture of carbon fiber reinforced plastic panels in the trailing edge of the wing of the F-111A aircraft in 1967. IN last years In aerospace products, you can increasingly find structures made of a three-layer “sandwich” with aluminum honeycomb core and carbon fiber skins. Currently, about 50% of the total weight of a Boeing 787 or Airbus A350 aircraft is made up of composite materials. In the automotive industry, composite materials have been used for quite a long time, mainly the technology for manufacturing aerodynamic body kits has been developed. Composite materials are used to a limited extent for the manufacture of suspension and engine parts.

However, until recently, enterprises used mainly manual laying out of parts from composites, and the serial production of products did not require deep automation of processes. Today, with the development of competition in the market, it is impossible to do without modern means design and production preparation, as well as without efficient equipment for working with composites.

Technologies for creating products from composite materials

In most cases, a chemically cured thermosetting resin is used as a binder filler, the curing process is characterized by exothermic chemical reaction. Mainly polyester, epoxy, phenolic and high temperature resins are used. Most often, in the manufacture of parts with complex configurations, technologies are used, the essence of which is to lay out a “dry” base followed by impregnation with a binder composition (“wet” molding, winding, injection, Resin Transfer Molding / RTM) or alternately laying out a “dry” base with film adhesive (vacuum impregnation, Resin Film Infusion / RFI). There are several basic technologies for manufacturing parts from composite materials, including manual and automated methods:

  • impregnation of reinforcing fibers with matrix material;
  • formation in a mold of reinforcement tapes and a matrix obtained by winding;
  • cold pressing of components followed by sintering;
  • electrochemical coating of fibers with subsequent pressing;
  • matrix deposition plasma spraying onto the strengthener followed by compression;
  • batch diffusion welding of monolayer tapes of components;
  • joint rolling of reinforcing elements with a matrix, etc.

In addition, the technology for manufacturing parts using prepregs (semi-finished products consisting of a base material impregnated with a binder composition) has become widespread.

Software

The task of designing a product from composite materials is the correct selection of a composition that provides a combination of properties required in a specific operational case. When designing reinforced polymer composite materials, computer data processing is widely used, for which a large number of different software products have been developed. Their use makes it possible to improve the quality of products, reduce the duration of development and organization of production of structures, and solve the problems of their rational design in a comprehensive, high-quality and quick manner. Taking into account the unevenness of loads makes it possible to design a hull structure made of reinforced composite with differentiated thickness, which can vary tens of times.

Modern software products can be divided into two groups: those that perform batch analysis of laminates in a “two-dimensional” or “beam/plate” formulation and in a three-dimensional one. The first group is programs like Laminator, VerctorLam Cirrus, etc. The “three-dimensional” solution is the finite element method, and there is a large selection among the available software products. There are various software products in the “composites modeling technology” market: FiberSim (Vistagy / Siemens PLM Software), Digimat (e-Xstream / MSC Software Corp.), Helius (Firehole Composites / Autodesk), ANSYS Composite PrepPost, ESAComp (Altair Engineering) and etc. .

Almost all specialized software from various companies has the ability to integrate with CAD systems high level- Creo Elements/Pro, Siemens NX, CATIA. In general, the work looks like this: the material of the layers is selected, the Common parameters package of layers, the method of forming layers is determined, the layer-by-layer method is used for the production of simple parts, for complex products zone or structural design methods are used. During the laying out of layers, their sequence is set. Depending on the method of production of the product (hand laying, molding, tape laying, fiber laying), a layer-by-layer analysis of the material is carried out for possible deformations. The composition of the layers is adjusted to the width of the material used.

After completing the formation of layers, the user receives data about the product, allowing them to be used for various purposes, for example:

  • output in the form of design documentation;
  • use as initial data for cutting material;
  • source data for the laser projector to indicate the contours of the pattern placement areas.

The transition to modern technologies for designing and preparing the production of products allows:

  • reduce the consumption of composite materials through the use of precise reamers and cutting machines;
  • increase the speed and improve the quality of manual laying out of material through the use of precise blanks and laser projections of their laying areas;
  • achieve a high level of product repeatability;
  • reducing the influence of the human factor on the quality of manufactured products;
  • reduction of qualification requirements for personnel involved in installation.

Equipment for creating matrices

Making a master model from wood is a labor-intensive and time-consuming process; to reduce the matrix manufacturing time and increase accuracy, the following are used: three/five-axis CNC milling machines, control and measuring machines or 3D scanners.

Gantry five-axis milling machine, (Figure 1), is available only to large manufacturers. Small companies they use robotic milling complexes on linear robot units (Fig. 2), or make master models from glued workpieces. In this case, a rigid hollow frame is taken as the basis of the workpiece, which is glued on the outside and then completely processed. Companies that do not have the opportunity to process the entire product take a different path: First, a simplified 3D model of the product is built in a CAD system using planes, and a rigid model is designed based on the simplified model. power frame from plywood. The entire external surface is then represented in the CAD system as cladding for the internal frame. The dimensions of the cladding are selected so that it can be milled on an existing CNC milling machine (Fig. 3). Then exactly assembled frame pasted over model cladding. With this method, the accuracy of the master model is lower and manual finishing of the cladding joints is required, but this allows you to create products whose dimensions significantly exceed the capabilities of existing CNC machines.

Rice. 1. Five-axis milling machine MR 125, capable of processing parts measuring 15x5 m and height up to 2.5 m

Rice. 2. Kuka robotic milling complex

Rice. 3. “Small” five-axis milling machine

Equipment for creating composites

The first step in mechanizing the molding process was the use of impregnation machines, which, in addition to impregnation, collect glass fabrics or fiberglass into multilayer bags with a total thickness of 4 - 5 mm. To mechanize processes, reduce the likelihood of personnel error, and increase productivity, for example, the spraying method is used, with which you can obtain external cladding, bulkhead panels and other fiberglass structures. The spraying method makes it possible to obtain molding angles by mechanization and provide higher labor productivity compared to molding angles manually molded from strips of fiberglass or fiberglass. The next stage in the development of the production of composite products is the introduction of an installation for automated winding of carbon-glass fillers. The first "robot" designed for laying dry fabric roll type was demonstrated by the American company Magnum Venus Plastech. For the first time in Russia, such equipment was introduced at JSC VASO. This equipment makes it possible to produce composite parts with a length of up to 8 m and a diameter of up to 3 m (Fig. 4).

To facilitate manual laying of fabric and reduce waste, cutting machines are used to automatically cut fabric/prepreg, laser projectors LAP and LPT for contour projection when laying out prepreg on production equipment. Using the laser projection module (Figure 5), it is possible to automatically generate projection data directly from the 3D model of the composite product. This way of working significantly reduces time costs, increases process efficiency, reduces the likelihood of defects and errors, and makes data management easier. The “software - cutting machine - projection laser” complex, compared to traditional laying, reduces the labor intensity of cutting by about 50%, the labor intensity of laying out by about 30%, and increases the utilization rate of materials, that is, you can save from 15 to 30% of material.

Molding carbon fiber reinforced plastics using the winding method makes it possible to obtain products with the highest deformation and strength characteristics. Winding methods are divided into “dry” and “wet”. In the first case, prepregs in the form of threads, strands or tapes are used for winding. In the second, the reinforcing materials are impregnated with a binder directly during the winding process. Recently, equipment has been developed that uses computer systems. This makes it possible to obtain tubular products with bends and irregular shape, as well as products with complex geometry. Equipment for winding using flexible technology, when reinforcing fibrous materials can be laid on a mandrel in any direction.

Rice. 4 Machine for automated winding and laying out of carbon fiber fillers Viper 1200 FPS from MAG Cincinnati

Rice. 5. Laser positioning system (green outline)

Equipment for monitoring the geometry and internal structure of the product

The contours of products often have curvilinear generatrices, which are not possible to check using traditional “plaz” methods. Using 3D scanning, you can determine how closely a physical sample matches a 3D computer model. For 3D scanning, you can also use an arm-type coordinate measuring machine (CMM) or a non-contact optical/laser scanning system. However, when used, non-contact scanning systems generally cannot work correctly on mirrored and high-gloss surfaces. When using “measuring arms”, several successive reinstallations will be required, since the working space, due to the design of measuring arms, is usually limited to a sphere with a radius of 1.2-3.6 m.

Also fiberglass materials There are a number of problematic areas. One of the main ones is quality control of the finished product (no air cavities) and corrosion during operation. For non-destructive testing of ship hulls made of composites, X-rays are widely used, but they strive to reduce it for a number of reasons. Recently, publications have begun to appear describing the detection of delaminations using infrared thermography (thermal imagers). At the same time, both thermal imaging and X-ray NDT methods detecting delaminations do not allow measuring their sizes and determining the depth of defects in order to assess their influence on changes in strength characteristics.

Conclusion

Currently, intensive development of automation of assembly of composite products, including equipment for creating matrices, is almost just beginning in Russia. Most often they only perform individual elements aerodynamic body kit for “tuning” cars. The implementation of the FiberSIM system at the Srednevsky Shipyard during the design and construction of the base minesweeper Project 12700, as well as at VASO, an automatic fabric laying machine, is a success. But these are individual examples; to increase competitiveness, the comprehensive introduction of new technologies is necessary.

Bibliographic link

Chernyshov E.A., Romanov A.D. MODERN TECHNOLOGIES FOR PRODUCTION OF PRODUCTS FROM COMPOSITE MATERIALS // Modern high technology. – 2014. – No. 2. – P. 46-51;
URL: http://top-technologies.ru/ru/article/view?id=33649 (access date: November 25, 2019). We bring to your attention magazines published by the publishing house "Academy of Natural Sciences"

During this method, pre-prepared fillers are used. Thanks to this method, high homogeneity of the product is guaranteed for strength, and indicators are controlled. However, the quality of the resulting product depends to a high degree on the skill and experience of the workers.

The production of hand-molded fiberglass products is divided into several stages. The first stage is called the preparatory stage, during which the surface of the matrix of the expected product is cleaned, then degreased and finally a layer of release wax is applied. At the end of the first stage, the matrix is ​​covered with a protective and decorative layer - gelcoat. Thanks to this layer, the outer surface of the future product is formed, the color is set and protection is provided from harmful factors such as water, ultraviolet light and chemical reagents. Negative matrices are mainly used to produce the finished product. After the special gelcoat layer has dried, you can move on to the next stage, which is called molding. During this stage, initially cut glass material is placed into the matrix; another type of filler can also be used. Next comes the process of forming the “skeleton” of the expected product. Then the resin with the catalyst, pre-mixed, is applied to the prepared glass material. The resin must be evenly distributed using brushes and soft rollers throughout the matrix. Final stage can be called rolling. It is used to remove air bubbles from a laminate that has not yet hardened. If they are not removed, this will affect the quality of the finished product, so the laminate must be rolled with a hard roller. Once the finished product has hardened, it is removed from the mold and subjected to machining, which includes drilling holes, trimming excess fiberglass around the edges, etc.

Advantages of this method:

  • exists real opportunity obtain a product of complex shape and considerable size with minimal investment;
  • the design of the product can be easily changed, since embedded parts and fittings are introduced into the product, and the price of the equipment and the required equipment is quite low;
  • To make the matrix, any material is used that is able to maintain its proportions and shape.

Disadvantages of this method:

  • significant costs manual labor;
  • productivity is quite low;
  • the quality of the product will depend on the qualifications of the molder;
  • This method is suitable for producing small-scale products.

2. Spraying.

This method is suitable for small and medium-scale production. The spraying method has many advantages over contact molding, even though there are some costs involved in purchasing equipment for this method.

A special installation allows you to apply protective covering and plastic. Due to this, there is no need for preliminary cutting of the material and preparation of the binder, as a result of which the part of manual labor is sharply reduced. Special installations automatically accurately count the doses of resin and hardener, and they also cut the roving into pieces required sizes(0.8 - 5 cm). After the cutting process, parts of the thread must fall into the binder stream and become saturated during transfer to the matrix. Through manual labor, the compaction process for fiberglass in the matrix is ​​carried out using a rolling roller.

A number of advantages in the production of fiberglass by spraying:

  • time is saved and useful areas due to the fact that there is no need to cut the material and prepare the binder;
  • it is possible to reduce the number of production areas by reducing the number of specially prepared places for molding;
  • the product molding speed increases;
  • control over product quality is simplified;
  • fund wages significant savings;
  • Due to the fact that roving is a relatively inexpensive material, the cost of the resulting product is significantly reduced.

When the binder is prepared in small quantities, then during manual molding up to 5% of the binder remains on the tools and walls of the container, which is quite uneconomical. It is known that the quality of the resulting product will depend on the skill and experience of the installation operator. This method uses the same tooling as during hand molding.

3. Pultrusion.


Pultrusion technology is based on the continuous production of uniaxially oriented profile products from fibrous plastics. A profiled product with a constant cross-section made of suitable material This is exactly what can be obtained by pultrusion.

Thanks to a special pultrusion machine, a fiberglass profile is produced. Such a machine consists of a section for supplying reinforcing materials, a die, a section for impregnation, a pulling unit, and a control unit heating elements and from the trimming section. It is better to strengthen the oriented fiber package in a dry state and impregnate it with a polymer composition pumped through the dry package. Thanks to this technology, air will not get into the material. Excess resin will flow back into the pan and be recycled. Roving, which is used as a reinforcing material, is unwound from reels in a dry state and collected into a bundle in a special way. Then the material enters the impregnation device - this is a special bath with resin, where it is completely wetted with polyester, epoxy or other binder. Then the already impregnated material is sent to a heated die, the task of which is to form the profile configuration. Then the composition hardens at the specified temperature. The result was a fiberglass profile, the configuration of which follows the shape of the die.

It has been proven that products produced by pultrusion have superior properties to parts made by classical molding methods. The increase in cost of this method is due to a number of advantages that are characteristic of this process. Benefits include strict control of fiber tension and directionality, reduced pores, and maintaining a constant fiber content in the composite. It is obvious that even the interlayer shear property is clearly improved. On this moment Several variants of the basic pultrusion process have been developed that are of interest to many and of great importance to the industry. Their advantages are good electrical, physical, chemical and thermal properties, high performance and excellent dimensional tolerance. One of these pultrusion methods is precisely intended for the production of permanent plate and sheet semi-finished products.

However, each method has its drawbacks. This method is characterized by such a disadvantage as the speed of the process, which will depend on the temperature and rate of hardening of the binder. It is usually small for low heat resistant polyester resins. Another disadvantage is that it is difficult to provide a constant cross-section of the product along its length, with the exception of products with not particularly complex shape sections - square, round, I-beam and others. To obtain the product, you must use only threads or strands. However, recently these disadvantages of the method for producing profile products have been gradually eliminated and the use of this process has expanded noticeably. A composition that is based on polyvinyl ethers and epoxy resins are used as polymer matrices. The use of such polymer matrices based on polysulfone, polyethersulfone and plasticized polyimide makes it possible to achieve a molding speed of rods with a diameter of about five mm at a speed of about one hundred and two m/min.

To obtain complex reinforced profile products, it is necessary to use the method of drawing layered materials that consist of fibrous mats or fabrics. Currently, methods have been developed for producing tubular products that combine winding of a spiral layer and broaching. Blades wind turbines who have complex profile cross section, can be cited as an example of the use of materials having complex circuit reinforcement Equipment for forming semi-finished products for sheet metal has already been developed. car springs, which have a curved surface and a variable cross-section.

4. Winding.

One of the most promising methods for molding fiberglass products is the fiber winding method, due to the fact that it creates the required filler structure in the products depending on their shape and operating characteristics. Thanks to the use of strands, tapes, threads as fillers, it ensures maximum strength of products. Moreover, such fillers are the cheapest.

The fiber winding process can be described as a relatively simple method in which reinforcing material in the form of a permanent roving (tow) or thread (yarn) is wound onto a rotating mandrel. Special mechanisms monitor the winding angle and the location of the reinforcing material. These devices move at a speed that matches the rotation of the mandrel. The material is wrapped around the mandrel in the form of strips touching each other, or in some special pattern until the mandrel surface is completely covered. Successive layers can be applied at one angle or at different angles winding until the required thickness is reached. The winding angle varies from very small, which is called longitudinal, to large - circumferential. This arrangement implies 90 0 relative to the axis of the mandrel, covering all spiral angles of this interval.

Thermosetting resin serves as a binder for the reinforcing material. In the wet winding process, the resin is applied directly during the winding itself. The dry winding process is based on the use of roving, which is pre-impregnated with resin in the B-stage. Hardening is carried out at increased temperature without excess pressure. The final stage of the process is based on taking the product from the mandrel. If necessary, finishing operations can be carried out: mechanical processing or grinding. The basic winding process is characterized by many options, which differ only in the nature of the winding, as well as design features, combination of materials and type of equipment. The structure must be wound as on a surface of rotation. However, it is possible to mold products of another type, for example, by compressing a still unhardened wound part inside a closed mold.

The design looks like a smooth cylinder, pipe or tubing, the diameter of which ranges from several centimeters to several tens of centimeters. Winding allows you to form products of conical, spherical and geodesic shapes. To obtain pressure vessels and storage tanks, an end cap must be inserted into the winding. It is possible to form products that will work under non-standard loading conditions, for example, external or internal pressure, compression loads or torque. Thermoplastic pipes and high-pressure metal vessels are strengthened when wound with external bands. The resulting products are characterized by a high degree of accuracy. However, there is another side to the winding process; this process is characterized by lower production speeds. The advantage is that absolutely any permanently reinforcing material is suitable for winding.

Machines can be used for the winding process different types: from various lathes and chain-driven machines to more complex computerized units characterized by three or four axes of movement. Machines that continuously produce pipes are also used. To facilitate winding of large tanks, portable equipment should be designed at the installation site.

The main advantages of the winding method:

  • a method of laying material that is profitable from an economic point of view due to the speed of the process;
  • possibility of adjusting the resin/glass ratio;
  • low dead weight, but high strength;
  • this method is not prone to corrosion and rotting;
  • relatively inexpensive materials;
  • good structure of laminates, due to the fact that the profiles have directional fibers, and good content of glass materials.

5. Pressing.

The pressing process consists of directly giving the desired shape to the product under the influence of high pressure, which is formed in the mold at the temperature of rapid hardening of the material. Thanks to external pressure in the material that is pressed, its compaction and partial destructuring of the previous structure occurs. The friction between contacting particles of material, which is formed during compaction, causes the generation of thermal energy, which will definitely lead to the melting of the binder. After the material enters a viscoplastic state, it spreads in the mold under pressure, forming a coherent and compacted structure. The hardening process is based on the cross-linking reaction of macromolecules due to polycondensation between the free groups of the binder. The reaction requires heat, during which low molecular weight, volatile substances are released, such as methanol, water, formaldehyde, ammonia, etc.

Parameters for direct pressing technology:

  • preheating temperature;
  • pressing pressure;
  • pressing temperature;
  • temporary exposure under pressure;
  • prepress parameters;

Pressure acts directly on the material in the mold cavity during direct pressing, so mold parts may wear out prematurely. Depending on the size of the product, the pressing cycle can range from 4 to 7 minutes. Direct pressing of plastics for reinforcement has two types, which depend on how the fiber filler is impregnated:

  • Dry, pre-impregnated canvases and fabrics are pressed;
  • They are pressed with impregnation exactly in the mold.

The first method is more popular. To produce products of relatively simple shapes, direct pressing is used. Due to the high demands placed on the quality of the outer surface of the part, automatic installations were created for dosing components when preparing prepreg blanks. Special automatic manipulators have been designed that load packages of blanks into multi-cavity press molds. The new generation of high precision presses are equipped with modern systems control, thanks to which it is possible to obtain parts with a high-quality surface, and their cost is approximately the same as steel parts.

6. SMC technology.


A serious obstacle to the spread of composite materials is the poor adaptation of traditional technologies for their production to the needs of modern large-scale production, which is also fully automated. Today, composite parts still remain “piece goods”. Expensive labor of experienced personnel contributes high contribution at a fraction of the cost of these materials. Despite this, in recent years we have made significant progress in the preparation of automated methods for the production of composites. SMC technology has become one of the most popular developments.

The final products using this technology are subject to a two-stage process. The first stage of the technology is characterized by the fact that prepreg is produced on an automatic conveyor unit, and already at the second stage the prepreg is processed in steel molds in finished parts. Let us describe these stages in more detail. Unsaturated polyester resin is used as the base for the binder material. Its advantages include low price and short curing time. The reinforcing component is chopped fiberglass, which is randomly distributed throughout the sheet volume. Long-term storage for several months at room temperature is ensured by the resin curing system. Chemical thickeners increase the viscosity of the binder after the glass fiber has been impregnated by several orders of magnitude, thereby improving the manufacturability of the prepreg and also increasing its shelf life. Mineral fillers that are added to the binder in large quantities, increase fire resistance finished products and, and the quality of their surface improves noticeably.

The resulting prepreg can be processed in an automatic process thanks to pressing in heated steel molds. These molds are similar in design to injection molds for thermoplastics. Thanks to the binder formulation, the prepreg hardens at a temperature of 150 C and a pressure of 50-80 bar at a speed of ~30 sec/mm of thickness. Very low curing shrinkage is important feature SMC technologies. Due to the high content of mineral filler and special thermoplastic additives, shrinkage is up to 0.05%. The resulting products have an impact strength of 50-100 kJ/m2, and a destructive bending strength of 120-180 MPa. It is economically feasible to use SMC technology when obtaining high-quality composite products in large quantities from several thousand to hundreds of thousands per month. Hundreds of thousands of similar materials are produced on the European market per year. The electric power, automobile and railway industries are the largest consumers of these materials.

7. RTM (Resin Transfer Molding) method.

The RTM method is based on the impregnation and injection molding of composites, during which the binder is transferred into a closed matrix that already contains fillers or preforms. Various fabrics of various weaves can act as reinforcing material, for example, multi-axial or emulsion material, and powdered glass mats. The binder is a resin that gels in 50-120 minutes and has a low dynamic viscosity. GOST 28593-90 determines the viscosity and gelation time of the resin.

This method is perfect for standard volumes of 500 -10,000 products per year. The design of the matrix consists of composite or steel forms that repeat the external contours of the part on both sides. The structures have high temperature properties that are held in place by the precise alignment of enclosed steel frames that are supported at the clamping locations.

This method is ideal for the production of matrices from 0.2m2 to 100m2. The matrix design consists of composite or steel forms. The circuit matrix consists of a lighter and more flexible design. The halves of the matrix are connected to each other under the influence of vacuum.

Advantages of RTM technology:

  • automated production, which reduces the random nature of human intervention;
  • there is a reduction and control of the amount of raw materials used;
  • the impact of the material on the environment is reduced;
  • working conditions have been improved;
  • relatively durable products are created due to better impregnation;
  • relatively cheap equipment.

Robotic complex For machining products made of composite materials are designed for mechanization and automation of some of the most labor-intensive operations in the technological cycle:

  • Trimming and removing technological flash
  • Milling grooves, recesses and positioners for embedded elements
  • Drilling and milling through holes of complex shapes
  • Milling through holes large sizes(window openings, hatches, etc.)

Robotic complex allows you to provide the following benefits:

  • Increased processing speed compared to manual methods
  • High repeatability and processing quality
  • Milling with high edge quality “in one pass”
  • Improving working conditions
  • Creation of additional knowledge-intensive jobs

At contact method During molding, the glass material is manually impregnated with resin using a brush or roller. Impregnation can be carried out simultaneously with rolling in the mold, or separately. Rolling is carried out to remove air from the laminate and uniformly distribute the binder.