RU2297303C2 - Center runner unit - Google Patents

Abstract

FIELD: foundry, possibly injection casting of metallic material in thixotropic state, for example casting magnesium base alloys.

SUBSTANCE: center runner unit is used for connecting nozzle duct of casting machine with runner system of molding equipment. Unit includes several regulators of temperature zones dividing by segments center runner length. At performing casting process localized temperature monitoring is realized. In place of nozzle to mold connection temperature lower than transition temperature of material to be cast to melt state is sustained. It provides practically fluid-tight joining of nozzle of molding machine with casting mold. Center runner unit includes isolating connection coupling for isolating heated casting sleeve against motion effort.

EFFECT: possibility for realizing flexible manufacturing process.

30 cl, 13 dwg

Description

FIELD OF THE INVENTION

The present invention generally relates to a central gate channel assembly for use in a mold. In particular, the invention relates to a central gate channel assembly used in injection or injection molding machines, and in particular, but not necessarily, the invention is applicable to the injection of metallic material in a thixotropic state into a mold in a mold cavity .

State of the art

Foundry bushings for foundry molds are widely known in the art. For example, in the book: Herbert Rees "Understanding Injection Molding Technology", copyright 1994, ISBN-1-56990-130-9, p.61 describes a heated central gate channel. In particular, the gating bushings provide a connection between the nozzle of the casting machine and the gating system of the mold for injection under pressure into the mold cavity of the at least partially molten molding mass. At least partially molten material, sometimes called a melt, is moved from the nozzle of the machine into a channel located inside the gate, and then into the cavity of the mold. During the casting process, a displacement sleeve is typically applied longitudinally to the gating sleeve to seal the connection between the nozzle of the casting machine and the gating sleeve. There are mainly two types of central gate channels, cold and hot.

Cold central gate channels do not heat. Any flow of molten material stopped in a cold central gate will freeze inside some part of the channel of the gate. Frozen material must be removed from the sprue bush before the next injection cycle. The hardened material is unsuitable for use and increases the cost of the part, since it is essentially a waste of the process.

Hot central gate channels are usually electrically heated. Heat to the gate channel can be supplied externally or internally. Typically, the hot runner channel keeps the material molten inside the runner channel using a single heating zone.

US Pat. No. 5,884,687, published March 23, 1999, to the Hotset patentee, describes the design of a hot runner with a heating chamber used in an injection molding machine. The supply sleeve contains a Central channel for receiving the molten material. A supply sleeve surrounds the heater, providing the formation of a single heating zone. One end of the supply sleeve is used to supply molten metal, and the applied movement force acts through a portion of the sprue sleeve. A plug of solid material is formed near the feeder, which is pushed out during the casting process with the injection pressure of the material applied.

From US patent No. 6095789, publication date 08/01/2000, the patent holder of Polyshot Corporation, known hot runner sleeve with adjustable heating. The sprue housing is surrounded externally by resistive heaters. The number of turns of the heater wire increases at the far ends of the sprue sleeve to provide greater heat emission at these ends to compensate for the high heat sink or high heat loss that occurs at the far ends. This solution is aimed at creating a constant temperature along the entire length of the sprue sleeve in a single zone of uniform heating.

From the international application WO 01/19552, the applicant Hotflo Die Casting, it is known to use the insert with gating channels made with a pointed end fairing, in combination with a separate transition channel. The temperature is regulated along the entire length of the central gate channel as one single zone of the same temperature. The material along the entire length of the central gate channel is at a temperature high enough to allow the material to flow. A separate attached crystallizer includes a transition channel located downstream of the central gate. To freeze the material located in the transition channel, the transition channel is regulated independently of the central gate.

US Pat. No. 6,353,511, published March 19, 2002 (the patent holder is the same as the applicant for the present invention), discloses a connection using a centering protrusion that provides an improved contact surface for connecting the elements through which the melt flows in a die casting machine injection and, in particular, the connection between the nozzle of the machine and another typical sprue sleeve in the case of forming a metal material in a thixotropic state. The coupling using the centering protrusion includes an annular cylindrical part of the first element, placed inside the cylindrical hole of the second element. This type of conjugation is characterized by good diametrical correspondence between the outer surface of the annular cylindrical part and the inner surface of the cylindrical hole mating in it, while a good correspondence between the diameters may provide for a small annular gap to maintain the initial melt leakage and connection along the axis over a sufficient length to ensure limited axial movement without deterioration seals. The connection using the centering protrusion allows, due to landing, to create a seal against melt leaks, which can be improved by an additional seal formed by hardened cast material that has leaked through a small gap.

In European patent No. 0444748, patentee Boekel et al., Published on 09/04/1991, a gate for a mold is described which comprises a number of thermal control zones formed along the gate.

Japanese Patent No. 2002-059456, the patentee of Atsuki et al., Discloses a nozzle for a casting machine for use in a metal casting machine that is equipped with means for controlling the formation of a cold plug in it.

In the known design of the assembly with a central gate channel, there are a number of problems that are associated with poor thermal regulation along the length of the gate, because there is only one temperature zone in order to maintain the temperature conditions in the injection mass flowing through the gate. For example, if there is only one zone of thermal regulation in which the temperature of the injection mass necessary for the casting process is controlled, it is impossible to independently control the temperature of the connection between the conjugate channel-forming elements for melt flow, since it is necessary to use a connection to ensure reliable sealing against leakage of the injection material made with a centering protrusion. Leakage of the casting mass is especially important in the processing of light alloys, for example, in the casting of magnesium in the thixotropic state, due to the possibility of rapid and uncontrolled oxidation at elevated temperatures of the process. In addition, it would be desirable to provide localized temperature control along the length of the central sprue channel in order to counteract, for example, undesirable changes in the temperature of the casting process, to control the formation of plugs in the sprue channel, or to provide overall flexibility of the process. Another problem is the sensitivity of the known central sprue assembly to permanent deformation due to the displacement force acting along the axis necessary to maintain a tight connection between the machine nozzle and the central sprue channel, especially when the central sprue channel is softened at high temperatures required for casting magnesium in the thixotropic state. In particular, the node of the central gate channel, when used, is clamped along the axis between the nozzle of the machine and the molding equipment (mold), and therefore, the central gate channel is subject to compression by the applied movement force, which is transmitted through the nozzle of the machine. The central sprue channel is sensitive to general compression deformation due to its thin-walled elongated structure, which provides a short heat transfer path with thermal conductivity (and therefore high sensitivity to temperature changes) between the heaters, provided along the length of the central sprue channel assembly and the casting material located in the channel for melt this node. Another problem is associated with undesirable fluctuations during the technological process, which are caused by the formation and pushing of plugs formed in the gate and having an unstable length, while changing the length of the plugs in the gate can be due to improper thermal regulation and the configuration of the channel for the melt.

Disclosure of invention

According to a first aspect of the present invention, there is provided a central gate channel assembly that connects a channel for melt the nozzle of a foundry machine with a gate system of a mold. The central gate channel assembly has such a configuration that allows it to be inserted into the mold and includes a contact surface located at the first end for connection with a nozzle, the configuration of which forms a connection with a reciprocal contact surface on the nozzle of the machine; a channel with a melt, which passes through the node of the Central gate channel from the first end to the second end; and a contact surface for connection with the mold at the second end, the configuration of which forms a connection with a mating contact surface on the mold for connecting the channel for the melt with the gate system of the mold. In addition, the central sprue channel assembly includes a large number of heat controllers located along the central sprue channel assembly and perform the function of regulating the temperature of a large number of temperature zones, which segment the length of the assembly with the central sprue in order to locally control the temperature of the casting mass within the regulation of sections of the channel with the melt. The central gate channel assembly may be an assembly structure with a connection of mating elements. In addition, any connection of the elements can be thermally controlled in order to provide a substantially tight (leak-free) connection between the nozzle of the casting machine and the gating system of the molding equipment (mold).

The mating contact surface at the central gate channel assembly can be configured to mate using a centering protrusion, such as described in US Pat. No. 6,353,511.

In another aspect of the present invention, there is provided a method of controlling temperature along a central gate channel assembly that connects the channel with the nozzle of a machine nozzle to a molding system of a molding equipment, comprising the steps of: i) forming a large number of temperature zones that segment the central gate channel assembly into segments its length, and ii) forming one or more temperature controllers to control the temperature in at least a subset of the plurality of temperatures s zones, and iii) operation of one or more controllers (control units) for actuating at least a subset of temperature controllers operating on the basis of feedback of the temperature of the temperature zones corresponding to these regulators determined by the conditions of the casting process.

Preferably, the method for controlling the temperature along the length of the central gate channel assembly further includes the step of forming one or more temperature zones as a nozzle sealing zone, which includes a contact surface for connecting to the machine nozzle and a part of the melt channel at the first end of the central gate channel assembly in which the temperature on the contact surface for connection with the nozzle is maintained below the melting point of the injection mass, while maintaining the injection mass inside the channel melt at any desired process temperature. The method, in addition, may include the step of forming one of the plurality of temperature zones as a conditioning zone adjacent to the nozzle sealing zone, in which the cast mass inside the channel with the melt within this zone is maintained at any desired process temperature . This method, in addition, may include the stage of formation of one or more temperature zones as a zone of cyclic temperature change located on the second end of the gate equipment for the controlled formation of a localized plug from the frozen cast mass in the channel section with the melt covered by this zone.

An advantage of the embodiments of the central gate assembly according to the present invention is to control the temperature and control a large number of individual temperature zones formed along the central gate assembly to maintain the cast mass in the melt channel at the temperature and state of aggregation necessary for the molding process. A large number of temperature zones, in addition, can provide temperature control of the mates made with the centering protrusion, to ensure a reliable tight connection between the nozzle of the machine and equipment for molding.

Another advantage of the embodiments of the central gate channel assembly of the present invention is its long-life configuration, even at the high operating temperatures required for casting magnesium in the thixotropic state. In particular, the vulnerable elements of the central gate channel assembly can be substantially isolated (unloaded) from the applied moving force.

Another advantage of the embodiments of the central gate assembly according to the present invention is the provision of a temperature cyclic zone that controls the formation of a plug from the cast mass used to control the flow of the cast mass. The cyclic change zone is made and regulated in such a way that the size of the pushed plug is constant and minimal, and, therefore, from injection to injection there is less variation in the parameters of the casting process.

This invention has been found to be particularly useful in the casting of metal alloys, such as thixotropic magnesium-based alloys in injection molding plants, although it is understood that this concept is widely applicable to any casting installations in which the injection mass is in plastic state or at least partially melted before being fed into the mold.

Brief Description of the Drawings

Next will be considered examples of embodiments of the present invention with reference to the accompanying drawings.

Figure 1 is a schematic illustration of a casting installation containing a clamping unit and an injection unit that can be used to implement the invention, a side view in partial section.

FIG. 2A is a more detailed cross-sectional view of a central gate channel assembly according to a preferred embodiment of the present invention, shown in a working position, inserted into the mold shown in FIG. 1.

FIG. 2B is another more detailed cross-sectional view of a central gate channel assembly according to the preferred embodiment shown in FIG. 2A.

FIG. 3 is an exploded view illustrating constituent elements of a central gate channel assembly according to the preferred embodiment of FIG. 2B.

FIG. 4A and FIG. 4B are perspectives of a front housing of a central gate channel assembly shown in FIG. 3.

Fig. 4C is a front view of Fig. 4A, an end view.

Fig. 4D is a front housing, a side view in cross section along line 4D-4D shown in Fig. 4C.

Fig. 4E is a view of another end of the front housing shown in Fig. 4A.

FIG. 5A is a perspective view of an alternative embodiment of the front housing shown in FIG.

5B is a front view shown in FIG. 5A, a sectional view.

6 is a sprue sleeve, a section along the line 6-6 in figure 3.

Fig. 7 is a perspective view of a cooling insert of a central gate channel assembly according to Fig. 3.

Fig.8 is a cooling insert shown in Fig.7, facing the injection unit, end view.

Fig.9 is a cooling insert shown in Fig.7, facing the mold, end view.

Figure 10 - cooling insert, a cross section along the line 10-10 in figure 9.

11 - the lower part of the cooling insert shown in Fig.7, side view.

Fig - cooling insert, a cross section along the line 12-12 shown in Fig.11.

Fig.13 is a cooling insert, a cross section along the line 13-13 shown in Fig.11.

The implementation of the invention

An embodiment of the invention is disclosed in the context and when placed in place within a known injection molding apparatus 10 shown in FIG. 1.

The injection molding machine 10 comprises an injection unit 14 and a clamp unit 12. The injection unit 14 provides injection of the casting mass into the mold. The injection unit 14 includes a frame 32, which typically serves as a support for the housing with electrical equipment for regulating and actuating the casting machine (not shown), as well as a support for the power supply housing (not shown). A support device (not shown) supports a prefabricated structure 34 including a cylinder 42. The support device (caliper) can be moved relative to the frame 32 by actuating two power hydraulic cylinders (not shown). A screw auger 4 is placed in the inner channel of the cylinder 42. During operation of the installation, the screw 40 rotates and usually moves along the axis along the axis 42 of the cylinder using the screw drive 36, as is well known in the art. The screw drive 36 may be made in the form of a combination of an electric motor for rotating the screw 40 and hydraulic drive elements used to move the screw 40 during the injection of the material. Those skilled in the art will recognize that the injection unit 14 can be provided exclusively with a hydraulic drive system or an electric motor drive. In addition, this illustrates one single stage of the injection unit with a screw, reciprocating. However, it will be understood by those skilled in the art that a two-stage injection unit can be used.

The clamp unit 12 opens, closes, and applies a closing force to the mold. The clamping unit 12 includes a stationary plate 16 and a movable plate 20 mounted on top of the frame 18, and a clamping drive (not shown) for making the movable plate 20 move relative to the fixed plate 16. The stationary plate 16 and the drive are usually connected by four traverses 38, of which only two are visible in FIG. The first half 24 of the mold is attached to the movable plate 20, and the second half 26 of the mold is attached to the fixed plate 16.

Those skilled in the art will recognize that the clamping unit 12 can be driven by a hydraulic drive, exclusively driven by an electric motor or a combination of an electric motor and hydraulic elements.

In a typical thixotropic casting machine, magnesium shavings 178 or other suitable material is fed into hopper 180 and dispensed through intake port 132 of cylinder 42. Auger 40 rotates and moves the injection mass from intake hole 132 along cylinder 42, with the injection mass passing the check valve 46, located at the end of the screw 40, and enters the accumulation zone 82, located in the cylinder head, in front of the nozzle 48. After the screw 40 delivers the material to the accumulation zone 82 and the nozzle 48, it moves in the cylinder 42 in the opposite direction to accumulate the necessary dose of material for injection. When a sufficient amount of material is accumulated in the accumulation zone 82, a dose is injected into the mold 24, 26 through a central gate channel. For injection, the hydraulic drive cylinder 36 of the screw forces the screw 40 to move in the mold direction and thereby injects material from the accumulation zone 82 into the mold through the nozzle 48. The check valve 46 prevents the material from flowing back into the cylinder 42 while the screw 40 moves forward. Along the cylinder 42 and nozzle 48, heaters 44 are placed (see FIG. 2A) to achieve and maintain the required process temperature and the aggregate state of the casting mass.

The central gate channel (gate) assembly of the present invention is illustrated by example with reference to the embodiment shown in FIG. 2A and FIG. 2B. The center gate unit 51 provides a connection between the melt channel of the nozzle 48 of the machine of the injection unit 14 and the gate system (not shown) of the second half 26 of the mold. The center gate assembly 51 is configured to be placed in the second half 26 of the mold and includes a contact surface 94 for interfacing with the nozzle at the first end, the configuration of which provides interfacing with the mating contact surface of the nozzle 48 of the casting machine. Channel 89 for the melt passes through the node 51 of the Central gate from its first end to the second end. The contact surface 93 at the second end, intended for connection with the mold, is formed to form a pair with the mating contact surface of the second half 26 of the mold to connect the channel 89 for the melt with the gate system of the mold. The central gate unit 51 also contains a plurality of temperature controllers located along the central gate channel unit 51 and providing temperature control of a plurality of temperature zones which divide the length of the central gate unit 51 into localized sections to regulate the temperature of the casting mass within the channel sections covered by the regulators with a melt. The central gate assembly may be an assembly of elements with a connection of mating elements. In addition, any pairing can be thermally controlled in order to provide a substantially tight connection of the nozzle 48 of the machine with the gate system of the second half 26 of the mold.

The contact connecting surface 49 of the nozzle 48 of the machine has a longitudinal surface formed by a cylindrical end centering protruding part 92. The connection between the contact surface 94 for connecting with the nozzle and the mating contact surface 49 of the nozzle 48 of the machine is made with a small gap in which the injection mass can seep and solidify with sealing the gap, which is typical for connection with a centering protrusion. Thermal control keeps the temperature in this interface below the crystallization temperature of the cast material. With such connections, the central gate unit 51 can expand and contract without loosing hermetic contact with the nozzle 48 or the second half 26 of the mold.

Preferably, the center sprue channel assembly further comprises a sprue sleeve 52 located inside the insulating coupler 53. The sprue 52 has a contact surface 94 for mating with a nozzle at its first end and a first contact surface 72 for connecting to an insulating coupler near the contact surface 94 for pairing with a nozzle. Channel 89 for the melt passes through the sprue sleeve 52 from the first end to the second end. A second contact surface 74 for interfacing with an insulating coupler is located at the second end. The first and second contact surfaces 72 and 74 for connecting with an insulating sleeve are configured to mate with the mating first and second contact surfaces 76 and 78 for connecting with a sprue sleeve made on an insulating coupler 53. The insulating sleeve 53 is configured so that it it was possible to place at least partially inside the second half 26 of the mold, and, in addition, to connect the channel 89 for the melt of the gating sleeve 52 with the gating system of the second half 26 of the mold. The insulating coupler 53 is preferably connected to the sprue sleeve 52 in such a way as to distribute the longitudinally applied displacement force acting through the first end of the sprue sleeve 52 to the second half 26 of the mold, as a result of which a substantial part of the sprue sleeve 52 is isolated (unloaded) from the applied displacement force . In particular, the insulating coupling 53 imposes an axial limitation on the first end of the sprue sleeve 52, while allowing unlimited longitudinal movement of the rest of the sleeve. The insulating sleeve also contributes to the thermal regulation of at least one of a large number of temperature zones, which (conditionally) segment the length of the sprue sleeve 51, due to the presence of one or more thermal regulators to reduce or increase the temperature of one or more of a large number temperature zones.

Preferably, the insulating coupler 53 is a prefabricated structure that includes a front housing 54 connected to the cooling insert 56. The front housing 54 is inserted into the second half 26 of the mold, while the cooling insert 56 is held in place by the installation ring 84. Through the installation ring 58 bolts 130 (see FIG. 3) pass and enter threaded holes 136 to hold the sprue sleeve 52 inside the insulating sleeve 53. Hold the elongated inner edge (on the mounting ring 58) AET sprue bushing 52 within the insulating sleeve whenever the nozzle 48 comes out of contact engagement with the sprue bushing 52.

Preferably, the front housing 54 provides a thermal bridge or channel that acts as a heat controller for transferring heat by thermal conductivity between the cooled second half 26 of the mold and the second end of the sprue sleeve 52, thereby controlling the temperature at the junction between the second contact surface 74 of the insulating interface a coupling and a second contact surface 78 for interfacing with a sprue sleeve, near the second end of the front housing. Preferably, this connection is a mating using a centering protrusion, in which the heat regulator provides the formation of a seal using a hardened cast mass, as described above.

The cooling insert 56 also serves as a heat regulator. The cooler circulation tube 66 provided with a connecting element 70 with a threaded adapter 168 provides a supply (outlet) of coolant, preferably oil, for cooling the insert 56, which selectively cools the gate 52, as will be explained in more detail below.

Along the longitudinal axis of the sprue sleeve 52, in addition, there are thermal regulators, for example, heaters 96a, 96b 96c and 96d, the configuration of which allows maintaining thermal contact. These heaters can be selectively controlled to control the temperature of the cast material as needed. Heater 96d may span the narrowed portion of the sprue sleeve 52. In this example, the narrowed portion of the sprue sleeve 52 provides a shorter heat transfer path through heat conduction and, therefore, a higher temperature sensitivity (quick response) when heat is transferred between the heater 96d and the cast material inside 89d channel for melt. It should be noted that the number of heaters and their placement can vary. In addition, the main part of the sprue sleeve 52 can be made of the same diameter along the entire length so that all the heaters have the same circumference.

Thermocouples installed along the length of the sprue sleeve 52 provide temperature feedback for the temperature zones with at least one controller (not shown), which controls the temperature setting for at least a subset of thermal controllers.

The flat support mounting ring 30 is interconnected with the mounting ring member 84 of the mold so that the second half 26 of the mold is strictly aligned with the injection unit 34, as is well known in the art.

The nozzle 48 is attached to the cylinder head 50 by means of bolts 60. The head part 50 is connected to the rest of the cylinder 42 by bolts 188.

FIG. 3 is an exploded view of a central gate channel assembly 51 according to a preferred embodiment of the invention. An access slot 100 is made in the front housing 54, allowing electrical wires 95 to be laid for heaters 96b, 96c and 96d and thermocouples. Bolts 68 pass through an oversized protrusion 102 of increased diameter in the front housing 54 to attach the housing 54 to the cooling insert 56. The cooling insert 56 is provided with a slot 104 for receiving electrical inputs of the heater 96a and a second slot 106 (see FIG. 7) for passing through them 66 cooling tubes.

The heating elements 96b, 96c and 96d are installed inside the housing 54, while the heating element 96a is installed inside the cooling insert 56. For the embodiment illustrated in FIG. 3, only four heating elements are shown as an example, and therefore it is understood that the number and the location of the heating elements may vary depending on the desire or need. In addition, the type of heater used is completely arbitrary, and the heaters used can include, without limitation, any combination of resistive, inductive, inductive-resistive heaters and, in addition, can be heaters in the form of thin or thick films.

As indicated above, the sprue sleeve 52 is installed inside the heating elements and is held inside them and between the front housing 54 and the cooling insert 56 using the mounting ring 56 and the connection by means of bolts 130. The mounting ring 84 abuts against the shoulder 108 made on the cooling insert 56 , and is bolted 62 to a support base plate 64 (see FIG. 2A). The second half 26 of the mold may be provided with an insulating plate 110 (FIG. 2A) located between the base plate 64 and the mounting ring 84 to provide thermal insulation between the fixed plate 16 and the second half 26 of the mold.

The front housing 54 is shown in more detail in FIGS. 4A, 4B, 4C, 4D and 4E. As shown in these figures, the front casing comprises an outer surface, the configuration of which enables placement of the front casing in the second half 26 of the mold. At the same time, the portion of the front housing 54 adjacent to the second end has a contact surface 93 for interfacing and providing a tight connection with the second half 26 of the mold. A cylindrical bore 90 passes through the front housing from its first end to the second end. Hole 90 creates a cavity surrounding a substantial part of the length of the sprue sleeve 52 between the first and second contact surfaces 72 and 74, which are used to connect to an insulating coupler. The gap formed between the sprue sleeve 52 and the insulating sleeve 53 creates an insulating air gap for the sprue sleeve, separating it from the relatively cold second half of the mold 26, and a space for passing the electrical terminals 95 of the heater and thermocouples. In addition, the hole 90 near the second end of the front housing 54 is bounded by a cylindrical surface that forms a second contact surface 78 for mating with the mating second contact surface of the sprue sleeve 52, which serves to interface with the insulating sleeve. The outwardly expanding conical inner surface immediately adjacent to the second end serves as a continuation of the melt channel 89, while the outwardly expanding conical surface contributes to the formation of a plug of molding material, as will be explained below. A groove 114, provided on the inside of the wall of the front housing 54, creates a volume for accommodating mounting clips for heaters 96b, 96c, and 96d. A hole 118 with a centering pin inserted into it provides the necessary orientation of the housing 54 relative to the cooling insert 56. The cooling insert 56 has a shoulder 112 for interfacing with the corresponding annular protrusion 120 (see Fig. 9), which creates a reliable connection of the housing 54 with the cooling insert 56 To connect the housing 54 to the cooling insert 56, bolt holes 116 are used, into which the bolts 68 are inserted.

FIGS. 5A and 5B illustrate another embodiment of the front housing 154. In this embodiment, the housing 154 is for the most part a substantially circular cylinder 184, and its end portion adjacent to the mold 26 (to its second half) is reduced diameter for placement inside the second half 26 of the mold. On each side of the circular cylinder 184, cutouts 182 are made in order to provide access to the holes 186 for introducing bolts into them, which allows the housing 154 to be attached to the cooling insert 56.

In Fig.6, the sprue sleeve 52 shown in Fig.3 is shown in more detail. At the first end of the sprue sleeve 52 is a recessed cylindrical hole 87, the inner surface of which serves as a contact surface 94 for interfacing with the nozzle. In addition, at the first end of the sprue sleeve 52 there is a circumferential flange 86, with the first contact surface 72 extending along the outer diameter of the flange 86 for coupling with an insulating coupler. A shoulder 138 is formed on the back (rear) surface of the circumferential flange 86, which serves as a mating surface with the cooling insert 56. In addition, a thermal resistance 124 in the form of an annular groove is formed on the rear surface of the flange 86. Thermal resistance 124 provides a certain degree of thermal insulation between the part of the sprue sleeve 52 in contact with the cooling insert 56 and the rest of the sprue sleeve 52; thereby reducing heat transfer by thermal conductivity from the channel 89 with the melt to the cooling insert 56.

A channel 89 for the melt passes through the sprue bushing 52, from its first end to the second, which may include a conical section tapering inward to the channel adjacent to hole 87 and gradually decreasing in diameter so that the channel with the nozzle melt corresponds to the channel for melt sprue bush. The melt channel, in addition, can have a stepped transition 170 located between the main part of the channel and the conical section expanding outward, directly adjacent to the second end of the sprue sleeve 52. The stepped transition 170 is used to shift a tube of a comparable length under the influence of the injection pressure during the transition from one injection cycle to another, while the expanding conical section 89d of the channel with the melt contributes to the formation and easy pushing of the cork frozen in the gate channel at the beginning each injection cycle under the influence of the applied injection pressure. The possibility of pushing the cork of a commensurate length is created by the appropriate choice of the sizes of the receiving device of the gate (not shown), located in the second half 26 of the mold, and the configuration of the gate system of the mold, which allows optimizing the melt flow for stable operation of the casting process.

At the second end of the sprue sleeve 52, there is a forward projecting centering annular portion 88, the outer surface of which forms a second contact surface 74 for interfacing with an insulating coupler. Along the length of the sprue sleeve 52 there are thermocouple termination points, for example, 122a, 122b and 122c, providing temperature feedback in the characteristic control zones, as will be described in more detail below.

Fig. 7 shows an enlarged perspective of the cooling insert 56. The thermocouple installation point 128 is located at the base of the groove 106 and is a blind hole in the side wall of the cooling insert, accessible through the groove 106 made in the base of the cooling insert. The position of the termination point 128 of the thermocouple is best shown in FIG. 10. A longitudinally oriented groove in the side wall of the cooling insert provides access to a heater 96a (not shown). A longitudinally oriented groove 114b passes through an internal channel in the cooling insert 56 and provides space for accommodating screw terminals (not shown) that support the heater 96a around the sprue sleeve as is well known in the art.

On Fig shows an end view of the cooling insert 56, which (the end) faces the mounting ring 84 and the locking ring 58. Through the locking ring 58, the bolts 130 (see figure 3) enter the threaded holes 136 made in the cooling insert 56 , to hold the sprue sleeve 52. As shown in FIG. 2B and FIG. 6, a shoulder 138 formed on the back surface of the flange 86 of the sprue sleeve 52 (see FIG. 6) engages with a surface 140 on the inner surface of the recessed hole 91 made in the cooling insert 56, and is held by stop 58. The surface of the ring of the inner diameter of the cylindrical bore 91 defines a first contact surface 76 for interfacing with a first contact surface of the sprue bushing 52, serving to connect with an insulating coupler.

Figure 9 shows a view of the cooling insert 56 from the end facing the front housing 54. The bolts 68 pass through the holes 116 in the front housing 54 (see figure 3) and enter the threaded holes 134 in the cooling insert 56, thereby holding the front the housing 54 is connected to the cooling insert 56. The shoulder 112 (see Fig. 4A) in the front housing 54 is mated to the annular part 120 of the cooling insert 56 to ensure reliable contact of the cooling insert with the housing 54. The remaining holes 172 are formed when forming the cooling channels and provided with plugs d I slab cooling channels, as will be clear from the following description.

Figure 10 shows the cross section of the cooling insert 56, drawn along the line 10-10 of the cross section shown in figure 9. A cooling liquid, preferably oil, circulates through the cooling channel through the cooling insert 56. The thermocouple installation point (socket) 128 is located near the contact surface of the cooling insert 56 with the sprue sleeve 52 (see FIG. 2B), since the temperature at this point is characteristic of the corresponding operation of the injection molding process, as will be described below. The hole 174 accommodates a pin 176 (see FIG. 3), which enters a corresponding hole (not shown) in the sprue sleeve 52, which allows the sprue sleeve 52 to be combined with the cooling insert 56.

11, 12 and 13 show a particularly suitable arrangement of cooling channels for the cooling insert 56. The cooling insert 56 is provided with cooling channels located in two different planes and connected by vertical portions of the connection (s) of these channels. Channels 144, 146 and 148 are shown in section in FIG. 13, and channels 150 and 152 are shown in section in FIG. 12. Vertical connectors 154, 156, 158, 160, 162 and 164 channels communicate with each other channels 144, 146, 148 with channels 150 and 152 and tubes 66 for supplying and discharging the cooler.

Tubes 66 for coolant and these channels are interconnected as follows. One tube 66, for supplying a cooler, is connected to a vertical connector 164 channels. A vertical channel connector 164 is connected to channel 144. Coolant flows through channel 144 to a vertical channel connector 162. A vertical channel connector 162 conveys the cooler to channel 150. The cooler flows through channel 150 to a vertical channel connector 160. A vertical channel connector 160 transports the cooler to channel 146. A cooler flows through channel 146 to a vertical channel connector 158. A vertical channel coupler 158 directs the cooler into a channel 152. A chiller flows through a channel 152 to a vertical channel coupler 156. A vertical channel connector 156 conveys the cooler to channel 148. A cooler flows through channel 148 to a vertical channel connector 154, and is transported (diverted) through a second pipe 66 for the cooler. In this way, the cooling fluid flows along the cooling insert 56 around the circumference of its circumference to provide very efficient and effective cooling of the cooling insert 56 and thereby the housing 54 attached thereto.

The thermal regulator of the insulating coupler may alternatively comprise a tubular coil for circulating fluid located around the contact surface for connection to the nozzle. Another possible alternative is a coil for circulating fluid located around the contact surface with the nozzle. The heat controller may include a hollow casing located around the contact surface with a nozzle through which the liquid circulates, or a large number of ribs can be made to realize convective heat transfer. The present invention is not limited to the specific temperature control means used in the heat controller.

For a better understanding of the invention, with reference to FIG. 1 and FIG. 2A, the preferred operation of the injection molding unit, in particular the central gate channel assembly 51 involved in the casting of the magnesium alloy in the thixotropic state, will be disclosed.

As noted above, the casting material is fed through the inlet 132, where it is received by the screw 40. The screw 40 moves the casting material inside the cylinder 42. At the same time, the material is also heated to achieve a thixotropic state when casting light metal alloys in a thixotropic state. The thixotropic material is fed through a check valve 46 into the accumulation zone 82, as noted above. The thixotropic molten material is maintained in a thixotropic state by means of heaters 44 installed in the nozzle 48 and in the cylinder 42, and by means of heaters 96a, 96b, 96c and 96d placed on the sprue sleeve. When a sufficient amount of material enters the accumulation zone 82, a moving force is applied and the auger is moved forward using the auger drive 36 to inject the injected dose of material into the mold 24, 26 through the central gate channel 51. When injecting, a small plug located at the end of the sprue sleeve 52 , pushed into the catcher cork, which is equipped with a mold (not shown), by a method well known to specialists in the field of injection molding. Said plug was formed during the previous injection cycle due to the opportunity for the melt located in the melt channel near the annular portion 88 to solidify and block the channel to prevent further exit of the molten material.

The displacement force generated by the injection counteracts the separation of the contacting surfaces, and as a result, the injection nozzle 48 is kept sealed relative to the center gate 51 assembly. In embodiments of the invention, the applied displacement force is transmitted through the nozzle 48 of the machine to the portion of the sprue sleeve 52 enclosed between the nozzle shoulder 48 and the cooling insert 56, and then through the cooling insert 56 is transmitted to the front housing 54 and the second half 26 of the form. This force transmission path isolates the portion of the sprue sleeve 52 adjacent to the portion enclosed between the nozzle 48 and the cooling insert 56 from the displacement force. In addition, since the sprue sleeve 52 can move laterally inside the hole 90, any pressure transmitted to the sprue sleeve 52 will be weakened. Therefore, the section of the sprue sleeve 52, which serves to isolate (unload) the force, can have a relatively thin-walled structure with a corresponding improvement in temperature sensitivity, without taking into account the action of the applied driving force, which is especially important at high operating temperatures characteristic of the process of casting magnesium in the thixotropic state .

Node 51 of the central gate channel in FIG. 2B is delimited by a large number of temperature zones for a typical process. The present invention is not limited to the specific number or configuration of temperature zones that may be necessary for alternative processes.

A large number of temperature zones include a nozzle seal zone Z1 located at the first end of the center gate assembly 51, which covers the contact surface 94 for mating with the nozzle and the melt channel portion 89a. The temperature in the zone Z1 of the nozzle seal is controlled so as to maintain the temperature necessary for sealing on the nozzle contact surface 94 and, therefore, the required connection temperature between the sprue sleeve 52 and the injection nozzle 48 of the casting machine, while maintaining the injection mass inside the section 89a of the melt channel at any operating temperature desired for the molding process. In particular, thermal control of the connection with the centering protrusion, which forms the interface between the sprue sleeve 52 and the nozzle 48 of the machine, is carried out so that the temperature on the channel surface is kept low enough to cure any cast material that can leak into the interface, thereby forming a seal . Therefore, to fulfill these conditions of thermal regulation in the zone Z1 of the nozzle seal, an equilibrium heat flux of heat conduction is established between the adjacent air conditioning zone Z2 of the sprue sleeve, the temperature of which is regulated by adjustable heaters 96b and 96c, and the heat regulator of the cooling insert 56. The runner is facilitated by the establishment of the equilibrium heat flow bushings 52 with local thermal resistance (key 124 in FIG. 6) between the first contact surface for interfacing with an insulating by means of a coupling and a nozzle contact surface such that the heat flux emanating from the adjacent conditioning zone Z2 is preferably directed to the melt channel portion 89a, and the heat flux from the junction of the sleeve with the nozzle is preferably directed to the cooling insert 56. Cooling insert 56 contains a system of channels for circulating the flow of the cooler, the temperature of which is set using a temperature regulator with feedback, acting according to the readings of thermocouples, sealed at a point 128 in the cooled insert 56 and at termination point 122c located in flange 86 of the sprue sleeve.

As noted above, a large number of temperature zones includes an air conditioning zone (air conditioning zone) Z2 located along the central part of the central gate channel assembly 51 adjacent to the nozzle sealing zone Z1 in which the casting mass is maintained inside the melt channel portion 89b that is maintained at the operating temperature required for the casting process. Thermal regulation in this zone is provided by the thermal controller / heaters 96a, 96b and 96c, based on feedback from the readings of the thermocouple installed at its termination point 122b (see FIG. 6).

A large number of temperature zones includes another conditioning zone Z3, located in the central gate unit 51 along a portion with a reduced outer diameter adjacent to the conditioning zone Z2, in which (in zone Z3) molding material inside the melt channel section 89a covered by this zone is again it is maintained at the operating temperature necessary for the casting process. As noted above, the shorter heat transfer path by thermal conductivity, due to the presence of a section with a reduced outer diameter, provides a relatively high temperature sensitivity for controlling the temperature of the cast material located inside the melt channel section 89d using a heat controller / heater 96d operating on based on feedback from the readings of the thermocouple installed at the termination point 122a (see FIG. 6). High thermal sensitivity compensates for frequent temperature changes near zone Z4 of cyclic temperature changes.

A large number of temperature zones also includes a temperature cyclic zone Z4 located at the second end of the central gate channel assembly 51, which serves for the controlled formation of a localized plug from the cast mass, which solidifies in the melt channel section 89d covered by this zone. Said plug can be used to prevent the injection of molten mass during various intervals of the casting process cycle and can eliminate the need for mechanical devices to cut off the melt flow. Thermal regulation of the cyclic zone is provided by the heat flux transmitted by thermal conductivity between the adjacent air conditioning zone Z3 of the sprue sleeve, which is controlled by thermostatic heaters 96d, and the heat regulator / heat transfer channel of the front case 54. The heat transfer channel through the front case is not actively regulated, but again provides a path for heat transfer by thermal conductivity between the cooled second half of the mold 26 and the sprue sleeve. As an alternative solution, the thermal regime of the cyclic change zone Z4 can be controlled at least until the molten material is partially re-melted, and another thermal regulator can contribute to this regulation.

A large number of temperature zones, in addition, may include a second sealing zone (not shown) located near the second end of the front housing 54, which includes a pair between the second contact surface 74 for connection with an insulating coupler and the second contact surface 78 for connection with gating bush. In the present embodiment, the second sealing zone is included in the cyclic temperature change zone Z4. The specified pairing is a pairing using a centering protrusion, the temperature of which, in practical implementation, is regulated in order to ensure the solidification of any cast material that can leak into the pairing, thereby forming a seal.

Thus, the embodiment disclosed above is a new construction of a central gate channel assembly, advantageous for use in molding equipment that requires thermal regulation and control of a large number of individual temperature zones. The present invention has been found to be particularly advantageous in the injection of metal alloys, for example magnesium-based alloys in a thixotropic state.

All patent documents of the United States and other countries, as well as the above articles are included in this detailed description of a preferred embodiment of the invention by reference.

The individual elements shown in general terms or indicated in the accompanying drawings in the form of blocks are well known in injection molding technology, and their specific design and operation are not essential to the work or better embodiment of the invention.

Claims (30)

1. The node (51) of the central sprue channel, designed to be placed in the molding equipment (26) and used to connect the channel (89) for melt the nozzle (48) of the casting machine with the sprue system of the molding equipment (26), while the node (51) the central sprue channel contains a sprue sleeve (52) designed to interact with an insulating coupler (53), and the sprue sleeve (52) contains a tubular body with first and second ends and has a contact surface (94) on the inner surface of the tubular housing at the first end, made to mate with the mating contact surface of the nozzle (48) of the machine, the outer surface of the tubular body to accommodate a large number of heat controllers, the first contact surface (72) to interface with an insulating coupling made on the outer surface of the tubular body on the first end, essentially adjacent to the contact surface (94) for interfacing with the nozzle, the second contact surface (74) for interfacing with an insulating coupling made on the outer surface of the tubular body, at its second end, and the melt channel (89) passing through the tubular body formed by its inner surface from the first to the second end, while the insulating coupling (53) comprises a tubular body having a first and second ends, the first contact surface (76) for interfacing with the sprue sleeve, made on the inner surface of the tubular body, at its first end, to accommodate the first contact surface (72) located on the sprue sleeve (52), the second end the actual surface (78) for interfacing with the sprue sleeve, made on the inner surface of the tubular body, near its second end, for placing a second contact surface (74) located on the sprue sleeve (52), the contact surface (93) for interfacing with the mold made on the second end of the tubular housing for interfacing with a mating contact surface made on molding equipment (26), the first contact surface (72) for interfacing with an insulating coupling and a first contact the contact surface (76) for interfacing with the sprue sleeve is made to interact essentially with the isolation of the sprue sleeve (52) from the displacement force applied from the nozzle (48) of the casting machine. 2. The node (51) of the central gate channel according to claim 1, in which the contact surface (94) for interfacing with the nozzle is made in the form of a cylindrical contact surface under the centering protrusion. 3. The node (51) of the central sprue channel according to claim 2, in which at least one of the large number of zones is a heat-regulated sealing zone that maintains the temperature on the contact surface (94) for mating with the nozzle below the transition temperature of the injection material into a liquid state, which provides a substantially tight connection with the nozzle of the casting machine (48). 4. The node (51) of the central gate channel according to claim 1 or 2, in which the contact surface (93) for interfacing with the mold is made in the form of a cylindrical contact surface for connection using a centering protrusion. 5. The node (51) of the central sprue channel according to claim 4, in which at least one of the large number of zones is a heat-regulated sealing zone that maintains the temperature of the contact surface (93) for interfacing with the mold below the transition temperature of the cast material into a liquid state, which provides a substantially tight connection with the molding equipment (26). 6. The node (51) of the central sprue channel according to claim 4, in which the insulating coupling (53) contains a continuation of the channel for the melt, passing along the inner surface of the tubular element at its second end, which connects the channel (89) for the melt sprue sleeve ( 52) with gating system of molding equipment (26). 7. The node (51) of the central sprue channel according to claim 6, in which the connection of the second contact surface (74) on the sprue sleeve (52), which serves to interface with the insulating coupling, with the second contact surface (78) on the insulating coupling ( 53), which serves to interface with the sprue sleeve, is a connection by means of a centering protrusion. 8. The node (51) of the central sprue channel according to claim 7, in which at least one of the large number of zones is a heat-regulated sealing zone that maintains the temperature of the contact surface (93) for interfacing with the mold below the transition temperature of the cast material into a liquid state, which provides a substantially tight connection with the molding equipment (26). 9. The node (51) of the central gate channel according to claim 7, in which the insulating coupling (53) further comprises a front housing (54) connected to the cooling insert (56), while the cooling insert (56) acts as a heat regulator adjacent to the contact surface (94), which serves to connect with the nozzle. 10. The node (51) of the central gate channel according to claim 9, in which the cooling insert (56) comprises a cooling channel (142) for circulating the cooling liquid. 11. The node (51) of the central gate channel according to claim 10, in which the cooling insert (56) is equipped with a thermocouple at the sealing point (128) located near the contact surface between the cooling insert (56) and the gate (52). 12. The node (51) of the central sprue channel according to claim 9, in which the front housing (54) provides a heat transfer channel between the cooled molding equipment (26) and the second end of the sprue sleeve (52) within the second sealing zone, wherein the transmission channel the heat acts as a heat regulator located next to the connection between the second contact surface (74) for coupling with an insulating coupling located on the gate (52), and the second contact surface (78) for interface with the gate, ra located on the insulating coupler (53). 13. The node (51) of the central sprue channel according to claim 12, in which the front housing (54) contains a through hole (90) that passes through the front housing (54) from the first end to the second end and provides a cavity around the sprue sleeve along most of its length. 14. The node (51) of the central gate channel according to claim 13, in which the through hole (90) also has a cylindrical surface near the second end of the front housing (54), which serves as the second contact surface (78) for connection with the gate , and the outwardly expanding cone closest to the second end, which is a continuation (89) of the melt channel. 15. The node (51) of the central sprue channel according to claim 14, in which the front housing (54) has an outer surface made to provide a contact surface (93) for connection with the mold. 16. The node (51) of the central sprue channel according to claim 1, in which the contact surface (94) for mating with the nozzle is the inner surface formed by a recessed cylindrical hole (87) at the first end of the sprue sleeve (52). 17. The node (51) of the central sprue channel according to clause 16, in which the first contact surface (74) for interfacing with the insulating coupling is formed by the surface on the outer diameter of the cylindrical flange (86) located on the first end of the sprue sleeve (52). 18. The node (51) of the central sprue channel according to claim 17, including thermal resistance (124), made in the form of an annular groove on the rear surface of the flange (86). 19. The node (51) of the central sprue channel according to claim 18, in which the channel (89) for the melt further comprises a conical section, tapering into the channel adjacent to the through hole (87), and a step transition (170) between the main channel section for the melt and the conical section expanding outward, immediately adjacent to the second end face of the sprue sleeve (52). 20. The node (51) of the central sprue channel according to claim 19, in which the sprue sleeve (52) furthermore includes at its second end an elongated annular portion (88) serving as a centering protrusion, the outer surface of which forms a second contact surface (74) for mating with insulating coupler. 21. The node (51) of the central sprue channel according to claim 20, in which the sprue sleeve (52) is equipped with heaters (96a, 96b, 96c and 96d) located along the longitudinal axis of the sprue sleeve (52), which can be selectively adjusted, the heaters act as a heat controller for selectively heating at least one air-conditioning zone located between the sealing zones. 22. The node (51) of the central sprue channel according to item 21, in which the sprue sleeve (52) is also equipped with thermocouples at points (122a, 122b and 122c) of their installation, located along the length of the sleeve, designed to seal thermocouples, which when used provide feedback on temperature, depending on the temperature conditions along the length of the sprue sleeve (52), with at least one controller that regulates the thermal modes of operation of thermal regulators. 23. The node (51) of the central sprue channel according to claim 22, in which the sprue sleeve (52) includes a reduced section in diameter near its second end to provide a rapid change in temperature of the cast material. 24. The node (51) of the Central gate channel according to claim 1, containing an insulating connector. 25. The method of temperature control along the node (51) of the central gate channel according to claim 1, connecting the channel for the melt nozzle (48) of the machine with the gate system of the molding equipment (26), which includes the stage of forming a large number of temperature zones (Z1, Z2, Z3, Z4), which divide the node (51) of the central sprue channel into segments along its length, while the specified large number of zones includes the nozzle sealing zone (Z1), which covers the contact surface (94) for connection with the nozzle and the section (89a ) channel with a melt, tries dressing at the first end of the knot (51); the formation of one or more thermal regulators (54, 56, 96) to control the temperature in a large number of temperature zones; the functioning of the controller to drive at least a subset of the heat controllers based on the feedback on the temperature of the temperature zone controllers and establish the required temperature, while the specified controller drives the specified heat controller in the nozzle sealing zone (Z1) to maintain the temperature on the contact surface (94) for connecting to the mold below the transition temperature of the casting material into a liquid state, which provides a substantially tight joint failure with the nozzle of a casting machine (48). 26. The method of controlling temperature along the node (51) of the central gate channel according to claim 25, comprising the step of forming at least one of a large number of temperature zones as a conditioning zone (Z2 or Z3) adjacent to the nozzle sealing zone (Z1), wherein the cast material within the portion (89b and 89c) of the melt channel covered by the conditioning zone is maintained at any desired temperature. 27. A method of controlling temperature along a node (51) of a central gate channel according to claim 26, comprising the step of forming at least one of a large number of temperature zones as a zone (Z4) of cyclic temperature change located on the second end of the node (51) of the central gate channel intended for the controlled formation of a localized plug from the hardened cast mass in the melt channel section (89d) covered by this zone. 28. The method of temperature control along the node (51) of the central gate channel according to claim 27, in which the node of the central gate channel includes a gate (52) enclosed inside an insulating coupler (53) comprising a front housing (54) connected to a cooling insert (56), while the cooling insert provides the function of a heat controller for the selective cooling of the nozzle sealing zone (Z1). 29. The method of temperature control along the node (51) of the central gate channel according to claim 28, wherein the gate sleeve (52) is equipped with heaters (96a, 96b, 96c and 96d) installed along the longitudinal axis of the node of the central gate channel (52), which can be individually controlled, while these heaters provide the function of a heat regulator for the selective heating of at least one air conditioning zone (Z2 and Z3). 30. The method of temperature control along the node (51) of the central sprue channel according to clause 29, in which the insulating coupling (53) provides a heat transfer channel with thermal conductivity between the cooled molding equipment (26) and the second end of the sprue sleeve (52) within the second zone sealing located in the zone (Z4) of cyclic change, and the heat transfer channel performs the function of a heat controller.

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