Hot pressing molds. Vacuum press and press sections MPP Lauffer for the production of printed circuit boards Payment form, delivery procedure, guarantee of heating plates
the process of reaching and maintaining a predetermined temperature of the forming element (mold). Cartridge heating elements and flat heaters are used to heat the molds. The type of heater is selected based on the shape of the available surface for heating (cylindrical hole - cartridge heating element, flat section - respectively flat heater).
Molds are commonly used to create batches of standard products. Heating of injection molds is carried out using various heating elements, but the most common are electric resistance heaters.
Mold Heaters are located depending on its design features, including the height of the matrix and the internal structure. It is recommended to place the heater in the mold body at a distance of 30-50 mm from the inner wall. Placing closer to the inner wall than the recommended distance increases the risk of manufacturing rejects.
The calculation of the number of heaters required to heat the mold is based on the following data: mold mass (or heat transfer surface area), operating temperature and heating element power.
Removable molds for casting are heated using heating plates containing cartridge heating elements.
Cartridge heating elements for heating molds
Cartridge heating elements for heating molds- heating elements that carry out heating in cylindrical openings. These are contact heaters, therefore, they require close contact with the heated surface. The voids are filled with assembly paste.
Coil heaters for heating molds
Coil heaters for heating molds- these are heaters that have a high specific power with relatively small overall dimensions.
Flat heaters for heating molds
Flat heaters for heating molds- electric resistance heaters with a flat surface, which maintain a given melt temperature during casting. During the production of the heater, it is possible to make holes in it of the required size in accordance with the design of the injection mold. Requires a tight fit to the mold when heated.
The invention relates to a mold containing a first part, including a housing (111), to which a molding zone (112) is connected to form a mechanical interface (115) between said molding zone and the housing, and containing inductors (132) located in the so-called longitudinal direction in the cavities (131) between the said interface (115) and the forming zone (112), and a cooling device (140) located at the interface between the forming zone and the body. The invention makes it possible to eliminate temperature gradients that lead to deformation of the mold. 14 p.p. f-ly, 6 dwg
The invention relates to a mold with rapid heating and cooling. In particular, the invention relates to a device for induction heating and rapid cooling of a mold intended for injection molding of a plastic material or metal in a liquid or pasty state.
The document EP 1894442, filed in the name of the applicant, describes a mold equipped with an induction heating device and a cooling device by circulating a heat transfer fluid. This known device contains a mold consisting of a stationary part and a movable part. Each of the parts is configured to accommodate an induction heating circuit and a cooling circuit. Each of these parts contains a body to which a part is connected, forming a molding surface that gives the final shape to the part cast in this mold. For each part of the mold, the forming surface is a heated and cooled surface, and the specified surface is in contact with the material of the molded part. Inductors are installed in the cavities under the said molding surface. Most often, these cavities are made by cutting grooves on the underside of said molding zone at the interface between this zone and the mold body. The cooling circuit is made in the form of channels drilled in the body and farther from the forming surface. This cooling circuit simultaneously provides cooling of this housing, which in a common embodiment is made of a material that is not sensitive to induction heating, and cooling of the forming surface. Finally, the body of each part is mechanically connected to the stand.
This configuration gives good results, but is difficult to use when the mold is large or when the mold surface is complex. Under these conditions, temperature gradients, which appear during both heating and cooling, lead to deformation of the mold as a whole, on the one hand, and, in particular, to differential deformation between the molding zone and the body, and this differential deformation leads to poor contact between these two elements and degrades the quality of cooling, creating thermal barriers between these two elements.
The object of the invention is to eliminate the above disadvantages inherent in the known technical solutions, by creating a mold containing the first part, including the body, to which the forming zone is connected, forming a mechanical interface between the said forming zone and the body, and containing inductors, located in the so-called longitudinal direction in the cavities between the said interface and the molding zone, and a cooling device located at the interface between the molding zone and the body. Thus, since the heating and cooling devices are located as close to the interface as possible, differential deformations do not affect the thermal conductivity between the heating and cooling devices and the forming zone. The inductors can be easily installed in shallow grooves that form cavities after the molding zone is connected to the body, thereby reducing the cost of machining such a mold.
Preferably, the invention is carried out in accordance with the embodiments described below, which are to be considered separately or in any technically feasible combination.
Preferably, according to an exemplary embodiment, the claimed mold comprises, at the interface between the body and the forming zone, a tape made of a thermally conductive material and adapted to compensate for differences in shape between the forming zone and the body.
According to a particular embodiment, the tape is made of graphite.
According to a version of this embodiment, said tape is made of Ni nickel.
According to another version of this embodiment, said tape is made of copper Cu.
Preferably, said tape is soldered onto the forming zone.
According to a second embodiment, compatible with the first, the inductors are inserted into sealed enclosures that can withstand temperatures of at least 250 ° C, and the cooling device comprises a heat transfer fluid flowing in cavities around the inductors.
According to a third embodiment, the cooling device uses the circulation of a dielectric fluid in the cavities around the inductors.
Preferably, the dielectric fluid is an electrical insulating oil.
According to a fourth embodiment, the cooling device comprises a cavity filled with a fluid that can change phase under the influence of temperature, and whose latent phase transition heat is sufficient to absorb the heat of the forming zone at a certain temperature.
According to a fifth embodiment, the cooling device allows gas to be pumped into the cavities around the inductors.
Preferably, the gas is injected in the transverse direction relative to the longitudinal direction. Thus, a vortex is formed in the air stream, which promotes heat exchanges. This swirl depends on the gas discharge pressure and on the angle between the discharge channel and the longitudinal direction of the cavities.
Preferably, according to this last embodiment, the cooling device of the claimed mold comprises a plurality of gas injection points along the length of the cavity in the longitudinal direction.
Preferably, the gas is air injected at a pressure exceeding 80 bar. The use of air as a cooling fluid simplifies the use of the device, in particular with regard to sealing problems.
According to a particular embodiment, the claimed mold comprises a second induction loop spaced from the first one relative to the interface and supplied with current by means of a separate generator.
According to a preferred embodiment, the body and the mold area are made of an INVAR type iron Fe and Ni nickel alloy, the Curie point of which is close to the transformation temperature of the material being cast. Thus, if the material of the body and the forming zone is ferromagnetic, that is, sensitive to induction heating, it has a low coefficient of expansion. When, when heating the material, its temperature approaches the Curie point, it becomes insensitive to induction heating. Thus, this embodiment makes it possible to control the differential expansion of the body and the forming zone, as well as between the body and the mechanical support of the said body on the press.
FIG. 1 shows a general example of implementation of the claimed mold, cross-sectional view;
in fig. 2 is a cross-sectional view of a claimed mold according to an embodiment comprising a belt between the forming zone and the body;
in fig. 3 shows a first part of a mold according to an embodiment of the invention, where the cooling device comprises a cavity filled with a material that can change phase at a given temperature, absorbing the latent heat of a phase transition, a cross-sectional view;
in fig. 4 shows a part of the claimed mold according to an embodiment of the invention, in which the cooling occurs due to the circulation of the heat transfer fluid in the cavities in which the inductors are located, a cross-sectional view;
in fig. 5 shows an example of an embodiment of a part of the claimed mold containing a cooling device by transverse injection of gas under pressure in the cavities in which the inductors are located, a cross-sectional view, while the orientation of the injectors in a longitudinal section is shown in the section plane SS;
in fig. 6 shows an example of an embodiment of a part of the claimed mold containing two spaced apart and separate induction circuits, a cross-sectional view.
As shown in FIG. 1, according to a first embodiment, the claimed mold comprises a first portion 101 and a second portion 102. The following description will refer to the first portion 101. One skilled in the art can easily apply the embodiments described for this first portion 101 to a second portion of said mold ... According to this embodiment, the first part 101 is fixed on a mechanical support 120. Said first part of the mold comprises a body 111, which is fixed on this mechanical support 12, and at its distal end with respect to said support 120 comprises a forming zone 112 connected to said body 111 using a mechanical attachment (not shown). Thus, there is a mechanical interface 115 between the body and the forming zone. The mold comprises a heating device including inductors 132 disposed in cavities 131 at the interface 115 between the forming zone 112 and the body 111, in this embodiment, said cavities made by cutting grooves on the inner side of the molding zone. The cooling device 140, shown here schematically, is also located at the interface 115.
As shown in FIG. 2, according to an exemplary embodiment, the claimed mold comprises a belt 215 between the interface 115 and the cooling device. This tape is made of graphite, nickel Ni or copper Cu, is thermally conductive and can compensate for differences in shape between the forming zone 112 and the body 111 at the interface 115 to ensure uniform contact between the body and the forming zone, as well as to provide good thermal conductivity between them. ... The belt material is selected depending on the temperature reached during forming. Preferably, the tape is brazed at the interface between the molding zone and the body after the mold is closed using a mold heating device for brazing. Thus, the shape adaptation is ideal.
As shown in FIG. 3, according to another embodiment, the cooling device comprises a cavity 341, 342, which is filled with a material capable of changing the phase at a certain temperature, and this change in phase is accompanied by the absorption of excess latent heat. Phase change is melting or evaporation. The specified material is, for example, water.
As shown in FIG. 4, according to yet another embodiment of the inventive mold, each inductor 132 is enclosed in a heat-resistant sealed envelope 431. Depending on the temperature to be created by the inductors, such envelope 431 is made of glass or silica, and it preferably has a closed porosity so that at the same time be sealed and withstand thermal shock when cooled. If the temperature reached by the inductors during operation is limited, for example, for molding certain plastic materials, the specified shell is made of a heat-shrinkable polymer, for example, of polytetrafluoroethylene (PTFE or Teflon®) for operating temperatures of the inductors up to 260 ° C. Thus, the cooling device provides for the circulation of a heat-transfer fluid, for example water, in the cavities 131 in which the inductors are located, while these inductors are isolated from contact with the heat-transfer fluid by their sealed envelope.
Alternatively, the heat transfer fluid is a dielectric fluid, such as a dielectric oil. This type of product is marketed in particular for cooling transformers. In this case, there is no need for electrical insulation of the inductors 132.
As shown in FIG. 5, according to another embodiment, the cooling is carried out by injecting gas into the cavity 131 in which the inductors 132 are installed. To increase the cooling efficiency, the gas is injected at a pressure of about 80 bar (80⋅10 5 Pa) through several channels 541 uniformly distributed in the longitudinal direction along the inductors 132. Thus, injection is carried out at several points along the inductors through the injection channels 542 transversely to said inductors 132.
In the longitudinal section along the SS, the injection channel 542 is oriented so that the direction of the fluid jet in the inductor cavity has a component parallel to the longitudinal direction. Thus, by appropriately selecting the injection angle, efficient cooling is obtained by swirling the gas along the inductor 132.
Temperature gradients, particularly in a housing mounted on a mechanical stand, can lead to warpage of the device or differential strain stresses. Therefore, according to a preferred embodiment, the body 111 and the forming zone 112 are made of an alloy of iron and nickel containing 64% iron and 36% nickel, called INVAR, and having a low coefficient of thermal expansion at a temperature below the Curie temperature of this material when it is in a ferromagnetic state. , that is, it is sensitive to induction heating.
As shown in FIG. 2, according to a last embodiment compatible with previous embodiments, the mold comprises a second row 632 of inductors spaced apart from the first row. The first 132 and second 632 rows of inductors are connected to two different generators. In this way, heat is dynamically distributed between the two rows of inductors in order to limit the deformations of the parts of the mold caused by thermal expansion in combination with thermal gradients that appear during the heating and cooling phase.
1. A mold containing a first part, including a body (111), to which the forming zone (112) is connected to form a mechanical interface (115) between said forming zone and the body, and containing inductors (132) located in the so-called longitudinal direction in the cavities (131) between the said interface (115) and the forming zone (112), and a cooling device (140) located at the interface between the forming zone and the body.
2. A mold according to claim 1, characterized in that it contains, at the interface between the body and the forming zone, a tape (215) made of a heat-conducting material and configured to compensate for differences in shape between the forming zone (112) and the body (111) ...
3. A mold according to claim 2, characterized in that the strip (215) is made of graphite.
4. A mold according to claim 2, characterized in that the strip (215) is made of nickel (Ni) or a nickel alloy.
5. A mold according to claim 2, characterized in that the tape (215) is made of copper (Cu).
6. A mold according to claim 1, characterized in that the inductors (132) are inserted into hermetic shells (431), made with the ability to withstand a temperature of at least 250 ° C, while the cooling device contains a liquid heat carrier flowing in the cavities ( 131) around the inductors (132).
7. A mold according to claim 1, characterized in that the cooling device (140) is configured to circulate the dielectric fluid in the cavities (131) around the inductors (132).
8. A mold according to claim. 7, characterized in that the dielectric fluid is an electrical insulating oil.
9. A mold according to claim 1, characterized in that the cooling device comprises a cavity (341, 342) filled with a fluid, made with the possibility of changing the phase under the influence of temperature, and the latent heat of the phase transition of which is sufficient to absorb the heat of the forming zone (112) at a certain temperature.
10. A mold according to claim 1, characterized in that the cooling device comprises a device (541, 542) for injecting gas into the cavity (131) around the inductors (132).
11. A mold according to claim 10, characterized in that the gas is injected by means of injectors (542) located in the transverse direction relative to the longitudinal direction.
12. A mold according to claim 11, characterized in that it contains several injectors (542) for injecting gas along the length of the cavity (131) in the longitudinal direction.
13. A mold according to claim 10, characterized in that the gas is air, injected at a pressure exceeding 80 bar (80⋅10 5 Pa).
14. A mold according to claim 1, characterized in that it contains a second induction loop (632) spaced from the first (132) induction loop relative to the interface (115) and supplied with current by means of a separate generator.
15. A mold according to claim 1, characterized in that the body (111) and the forming zone (112) are made of an INVAR-type iron-nickel alloy.
The invention relates to mechanical engineering, in particular to heat treatment of parts, and can be used for the manufacture of inductors for devices for high-frequency hardening of products, widely used in various sectors of the national economy.
The invention relates to a mold containing a first part, including a body, to which the forming zone is connected to form a mechanical interface between said forming zone and the body, and containing inductors located in the so-called longitudinal direction in cavities between said interface and a molding zone, and a cooling device located at the interface between the molding zone and the body. The invention makes it possible to eliminate temperature gradients that lead to deformation of the mold. 14 p.p. f-ly, 6 dwg
When designing molds for hot pressing, the determining factors are the geometric shape and dimensions of the product, as well as the heating method and the conditions for creating a protective atmosphere. By hot pressing, products are obtained, in general, of simple shapes, therefore, the design of the mold is simple. The main difficulty lies in the
Boron of the mold material, which must have sufficient strength at pressing temperatures, must not react with the powder to be pressed.
At pressing temperatures of 500 ... 600 ° C, heat-resistant nickel-based steels can be used as the mold material. In this case, high pressing pressures (150 ... 800 MPa) can be used. To prevent bonding of the pressed powder with the inner walls of the matrix and to reduce friction, the forming surfaces are coated with a high-temperature lubricant. However, the choice of lubricants is limited, as almost all of them volatilize during the hot pressing process. Mica and graphite are mainly used as lubricants.
Mica is used at low pressing temperatures. Graphite retains high antifriction properties at high temperatures. It is used in the form of a suspension of flake or silvery graphite in glycerin or water glass. Also used are combined molds made of a graphite matrix, lined inside with low-carbon steel, and the steel insert is chrome-plated to avoid interaction with the graphite of the matrix. For the manufacture of dies and punches operating at pressing temperatures (800 ... 900 ° C), you can use hard alloys. In the case of high hot pressing temperatures (2500 ... 2600 ° C), graphite is the only material for molds. Compared to other materials, it has good electrical characteristics, is easy to process and creates a protective atmosphere on the surface of the product, burning out during the hot pressing process. Since the pressing force decreases with an increase in the temperature of the process, the strength of graphite matrices is in most cases quite sufficient.
For the manufacture of molds, graphite is used with a fine-grained structure and without residual porosity, otherwise the pressed powder can penetrate into the pores, which deteriorates the quality of products due to an increase in friction between the walls of the mold and the powder.
Since the service life of graphite molds is rather short and it is extremely difficult to completely avoid the carburization of pressed products, a special multicomponent low
a keel alloy for molds in which powders of titanium, zirconium, thorium and other metals are pressed. The strength of the alloy at a temperature of 950 ... 1000 ° C is approximately 40-50 times higher than the strength of pure titanium. Oxides and silicates of refractory metals, in particular zirconium oxide, are also used for the manufacture of molds.
There are the following methods of electric heating of powders during hot pressing:
Direct heating by passing an electric current directly through the mold or powder to be pressed;
N indirect heating by passing a current through various resistance elements surrounding the mold;
P direct heating of the mold and powder by high frequency currents (HFC) or induction heating;
Indirect induction heating of the shell in which the mold is placed.
The hot pressing mold is designed depending on the heating method. In fig. 3.22 shows mold designs for double-sided hot pressing in combination with heating.
Rice. 3.22. Diagrams of mold designs for double-sided hot pressing in combination with heating: a- indirect heating; 6 - direct heating when supplying current to the punches; v - simple heating when supplying current to the matrix; G - induction heating of a graphite matrix; d - induction heating of the powder in a ceramic mold; 1 - heater; 2 - powder; 3 - briquette; 4 - matrix; 5,6 - punches; 7 - insulation; 8 - graphite contact; 9 - graphite punch; 10 - graphite matrix; 11 - ceramics; 12 - inductor; 13 - ceramic punch; 14 - ceramic matrix
With indirect heating (Fig. 3.22, a) the design of the mold is complicated by the need to use additional heaters. With direct heating of punches by passing current (Fig. 3.22, b) overheating of punches and, as a result, curvature is possible. Current supply to the matrix (Fig. 3.22, v) provides a more uniform heating of the powder, but structurally the mold becomes more complicated. Induction heating of the graphite matrix is applied (Figure 3.22, G) and a ceramic matrix (Figure 3.22, E).
The presses are designed for double-sided veneering of flat surfaces at a maximum operating temperature of 120 ° C. They are used in medium-sized enterprises for the production of furniture, doors, and other flat joinery. The heating principle is thermal oil, which heats up to operating temperature in an electric boiler and circulates through the stoves using a hydraulic pump. Press plates with a liquid circulation loop have thermal insulation installed to keep the temperature inside the plates. All press functions are controlled from the main panel. The design of the presses is made of welded beams, which ensures greater reliability and strength of the presses.
| vendor code | Plate size, mm | Pressing force, tons | Add to the list | Price | |
|---|---|---|---|---|---|
| In stock | 2500 x 1300 | 120 | 8 x 100 | Find out the price | |
| In stock | 2500 x 1300 | 120 | 8 x 100 | Find out the price | |
| 2500 x 1300 | 120 | 8 x 100 | Find out the price |
The presses are designed for double-sided facing of door planes, furniture blanks, facing panels, etc. with fine wood veneer, plastic, as well as for assembling door leaves under hot pressing conditions. The body is made of welded profiles. Loading the press from three sides. Prefabricated welded plates for high specific pressure and high temperatures. The parallelism of movement of the press plate is ensured by means of a system of toothed racks and gears and four vertical guides.
| vendor code | Plate size, mm | Pressing force, tons | Number and diameter of cylinders, mm | Add to the list | Price |
|---|---|---|---|---|---|
| 2500x1300 | 120 | 6 | Find out the price | ||
| 2500x1300 | 90 | 6 | Find out the price | ||
| 3000x1300 | 120 | 8 | Find out the price | ||
| 3000x1300 | 90 | 8 | Find out the price | ||
| 3500x1300 | 120 | 10 | Find out the price | ||
| 3500x1300 | 90 | 10 | Find out the price |
VP series presses are designed for double-sided facing of flat panel parts: door leaves, furniture blanks, facades, wall panels, etc. The presses can be used to assemble panel and frame-panel door leaves. The supporting frame of the presses is made of welded beams obtained by the hot-rolled method. As standard, the presses are equipped with solid steel plates with holes drilled along the entire length for the circulation of the heating medium. The presses are equipped with a toothed rack system and side guides that ensure absolute parallelism of lifting / lowering the plates. The design of the hydraulic system guarantees high operational reliability. Chrome plated cylinders.
| vendor code | Plate size, mm | Pressing force, tons | Number and diameter of cylinders, mm | Add to the list | Price |
|---|---|---|---|---|---|
| 2500 x 1300 | 100 | 6 x 85 | Find out the price | ||
| In stock | 2500 x 1300 | 100 | 6 x 85 | Find out the price | |
| 2500 x 1300 | 100 | 6 x 85 | Find out the price | ||
| 2500 x 1300 | 120 | 8 x 85 | Find out the price | ||
| 3000 x 1300 | 100 | 8 x 85 | Find out the price | ||
| In stock | 3000 x 1300 | 120 | 8 x 85 | Find out the price |
Designed for double-sided facing of door planes, furniture blanks, facing panels with veneer of valuable wood species, plastic, as well as for assembling door leaves under hot pressing conditions. The frame is welded from massive steel beams, which ensures the strength and rigidity of the structure at maximum pressure. Monolithic drilled slabs retain their geometry over long service lives. The cylinders are coated with a thick layer of chrome, which provides smooth lifting / lowering and long life of the seals and pistons. The hydraulic pump operates in an oil environment to reduce noise levels and improve cooling. Press functions are controlled from the main panel.
| vendor code | Plate size, mm | Pressing force, tons | Number and diameter of cylinders, mm | Add to the list | Price |
|---|---|---|---|---|---|
| 3000 x 1300 | 120 | 8 x 100 | Find out the price | ||
| 3000 x 1300 | 120 | 8 x 100 | Find out the price |
Designed for double-sided facing of door planes, furniture blanks, facing panels, etc. with veneer of valuable wood species, plastic, as well as for assembling door leaves under hot pressing conditions. The presses are designed taking into account all applicable safety standards. and are equipped with special 4 torsional safety guides. All press functions are controlled from the main panel. The structure of the press is made of welded beams, which ensures greater strength and reliability of the press. Cast plate with drilled holes. Timer for automatic opening of slabs. Unique patented hydraulic cylinder design.
| vendor code | Plate size, mm | Pressing force, tons | Number and diameter of cylinders, mm | Add to the list | Price |
|---|---|---|---|---|---|
| In stock | 2500 x 1300 | 100 | 6 x 100 | Find out the price | |
| 3000 x 1300 | 100 | 6 x 100 | Find out the price | ||
| In stock | 2500 x 1300 | 100 | 6 x 100 | Find out the price | |
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Hot pressing is one of the most widespread technologies for veneering and manufacturing of glued wood products. The technique makes it possible to use in work any materials that are resistant to high-temperature processing. Hydraulic hot presses are ideal for the batch production of wood furniture, joinery and various types of building finishes. The design of the hot pressing press is a solid frame with rigidly fixed and movable plates. A system of hydraulic cylinders is located in the lower part of the device, which ensures the movement of the working body and the required level of pressure on the surface of the package being processed. The workpiece is heated by built-in electrical elements or a heat carrier. The oil or liquid obtains the desired temperature in the boiler and forms a thermal field in the channels drilled in the slab cavity.  The direct purpose of the equipment is:
Surface cladding is performed using natural and artificial coatings. For finishing, veneer, decorative types of plastic, polymer film or paper are used. Bent-glued elements are created using a matrix of a given shape, installed on the working plates. Benefits of usingThe units are used in the in-line production of products in furniture and carpentry workshops, and are often used for the implementation of individual design projects. A hot press for veneering is in demand at enterprises with a medium and large volume of activity and during operation it shows:
The surface of products that have undergone lining with the use of heat treatment is distinguished by an increased strength of the finish, resistant to external factors and not having the property of flaking during operation. Classification and features of speciesThe division of hydraulic hot pressing presses into types is based on the degree of automation:
The optimum pressure level is set using a potentiometer integrated into the machine structure, and the processing temperature is controlled by a thermostat. An automatic timer controls the planned holding time of the workpiece under the press and carries out the opening of the plates at the end of the process. |
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