RU210235U1 - PRINTHEAD FOR 3D PRINTING WITH HIGH-TEMPERATURE POLYMERS - Google Patents

Abstract

The utility model relates to printheads for 3D printing with high-temperature polymers using FFF/FDM technology. The head is formed from a filament heating unit and a supply unit feeding the filament to it. The filament (23) moves along the Teflon tube (22). For the purpose of efficient cooling, the head is equipped with a liquid radiator (6). The radiator (6) is made in the form of a box, the walls of which contain channels for the coolant. The filament supply mechanism (5) is located in the radiator (6). The supply and discharge of the circulating liquid to the radiator (6) is carried out through pipes (25) connected to sealed terminals (24). The terminals (24) are detachable and installed in the end cap (8) of the radiator (6). In the branch pipe (25) for supplying coolant, there are wires (21) for connecting to the control system and a tube (22). An effective cooling system increases the wear resistance of the mechanical components of the print head, reliably protects the filament from premature melting to the melting zone. The temperature range for thermoplastic melting has been significantly extended upwards. Stable operation in high temperature conditions, up to 300°C and above. Increased continuous 3D printing time at high temperatures. 14 FIG.

Description

The utility model relates to the engineering field, namely to 3D printers operating on FFF/FDM technology, in particular to printheads of engineering polymers designed for installation on 3D printers of volumetric printing of various layout schemes in order to work with high-temperature polymers such as, for example, polyetheretherketone (PEEK) and various combinations based on it. The main areas of application are 3D printing used in medicine and prosthetics, the manufacture of complex engineering products operating at high temperatures and loads, as well as the use in engineering industries, printing molds and other products of simple and complex geometric shapes using additive technology.

FDM technology (from the English fuseddepositionmodeling, FDM) is an additive technology for modeling by layer-by-layer deposition. The term FFF (from the English fusedfilamentfabrication "production by fusing threads") is similar, equivalent in meaning and purpose, to the term FDM.

In 3D printing using FFF / FDM technology, objects are formed by layer-by-layer laying of the working material, which is thermoplastics. The print head, which contains an extruder and a mechanism for supplying working material to it, often referred to simply as an "extruder", melts a plastic filament (otherwise - a filament, from the English filament "thread; fiber"), stacking layer by layer in accordance with the digital model of the object. Sticking together, the layers form the future product. The movement of the print head is controlled by a three-coordinate kinematic system.

The use of thermoplastic in the form of a thin filament fed into the printhead is the traditional way of supplying media, but there is an alternative use of polymer granules instead of filament.

3D printed products made from high temperature polymers such as PEEK are becoming more and more widely used. have increased strength and resistance to high temperatures, they are able to replace metal products, while remaining much lighter.

However, engineering difficulties arise when working with such materials.

The extrusion of high-temperature polymers is carried out at a temperature of the order of 300°C and above, and the process takes place in a sealed working chamber with a constant high temperature. The temperature value is adjusted depending on the working material used and the selected operating mode of the 3D printer.

The implementation of the printing process in a heated working chamber allows you to better control the mechanical characteristics of the created product, because. the working material gets from the hot extruder to the heated table on which the product is formed, following through the hot medium, and this increases the adhesion of the layers of the created product and protects it from warping and twisting.

A negative consequence of the described 3D printing process is the increased wear of the mechanical components of the printer due to operation at elevated temperatures, the need to use parts made of high-temperature materials in mechanical components, which leads to an increase in both the initial cost of the 3D printer and the cost of its maintenance.

In addition, FFF/FDM technology is characterized by the problem of premature softening of the filament before it enters the melting zone due to the high heating temperature of the extruder nozzle, which adversely affects the quality of printed products. When working with high temperature polymers, due to the implementation of the process in a sealed working chamber with a constant high temperature, this problem is exacerbated.

Thus, the double impact of high temperature (from the extruder nozzle and from the heating of the sealed working chamber) on the mechanical components of the 3D printer, as well as the change in the physical properties of the thermoplastic due to high temperatures, causing premature softening of the filament and clogging of the extruder nozzle, lead to process interruption. 3D printing in order to cool overheated structures, filaments and eliminate problems that have arisen.

An extruder is known from the prior art (utility model patent No. 203882 RU, IPC B29C 48/395, B33Y 30/00, publ. 04/26/2021), containing a housing in which an inlet fitting for feeding granules is located, a cylinder with a screw installed in it , liquid cooling nozzle, liquid cooling labyrinth and pellet sensor. A heater and a nozzle are located on the cylinder. The inlet fitting for supplying granules is made with gas outlet holes. The screw is made with a constant width of the helical groove, but with a changing area, and contains four zones: loading, compression, homogenization and dosing. The cylinder has three heating sections, each heating section has one to two heaters and one temperature control sensor. An electric motor equipped with a gearbox is connected to the housing.

Known extruder is designed to work on technology FDM/FFF with a wide selection of refractory thermoplastic polymer materials with a melting point of up to 500°C as a consumable.

In the design of the well-known extruder, the technical problem of increasing the reliability of work with consumables of high refractoriness is solved, among other things, by making the body with a liquid cooling labyrinth.

The disadvantage of this technical solution is the insufficient protection of the mechanical components of the extruder. Since 3D printing of refractory thermoplastic polymer materials is carried out in a sealed working chamber with a constant high temperature, the mechanical parts of the extruder located outside the liquid-cooled labyrinth housing will be subject to overheating, which will reduce the reliability of the extruder.

In addition, the well-known extruder is designed to work with granules, not with filament, while in granular extruders there is still an unresolved problem of controlling the volume of the working material squeezed out by the screw, and this negatively affects the quality of manufactured products.

As a prototype, a printing unit for 3D printing with high-temperature polymers using FDM technology (utility model patent No. 189218 RU, IPC B41J 2/00, publ. 05/16/2019), including two easily removable extruders with heating elements, locking the nozzle of the inactive extruder, a filament feed mechanism, pinch rollers configured to press the filament against the feed mechanism for the currently active extruder, and a toothed gear. The pressure rollers are made in the form of toothed gears fixed at the ends of the angular lever and mounted with the possibility of engagement with the toothed gear. Each extruder is equipped with a liquid cooler. The filament supply channel passing through the radiator and thermal barrier is a hollow cylindrical ceramic tube. Extruder nozzles are made of wear-resistant titanium alloy. The radiator and feeder are enclosed in a thermally insulating housing. According to the description, the filament threads move along Teflon tubes.

The increase in the reliability of the 3D printing process with high-temperature polymers declared in the prototype is provided, among other things, by the presence of a liquid radiator, a hollow cylindrical ceramic tube of the filament supply channel passing through the radiator and thermal barrier, as well as the presence of a thermally insulating housing that closes the liquid radiator and the filament supply mechanism.

The disadvantage of the prototype is the risk of gradual heating of the printing block during 3D printing due to the absence of its own cooling system in the thermally insulating housing.

The filament supply mechanism, as well as part of the filament supply channel, are located outside the liquid radiators. Under the conditions of high-temperature printing, taking into account the technologically necessary heating of the working chamber, where the product is formed, the removal of excess heat only due to one liquid radiator involved in the 3D printing process will not fully protect the mechanical components and the filament from overheating. As a result, the reliability of the printing unit and the quality of manufactured products will be reduced.

The objective of the proposed utility model is to develop a print head design that allows you to create products from high-temperature polymers and ensures stable operation at high, up ^to 300 ° C and above, temperatures inside a sealed working chamber and a long time of continuous 3D printing.

The technical result consists in a significant increase in the temperature range for thermoplastic melting and an increase in the reliability of the print head due to an efficient cooling system that makes it possible to increase the wear resistance of the mechanical units of the print head, reliably protect the filament from melting, and increase the time of continuous operation of 3D printing at high temperatures.

To achieve the claimed technical result, a print head for 3D printing with high-temperature polymers is proposed, containing an extruder with a heating block, a thermal barrier, a filament feed mechanism, a liquid radiator through which the filament moves through a Teflon tube to the extruder nozzle, wires connecting to the print head control system , while the heating block and the extruder with a nozzle are installed on the outer lower side of the liquid radiator, according to the utility model, the liquid radiator is made of a material with high thermal conductivity and has the form of a box formed from a rectangular body with a wall thickness of at least 4 mm, closed at the ends covers, each of which is screwed to the radiator housing through a spacer plate, while in the liquid radiator there is a system of channels for cooling liquid, formed from through channels in the walls of the housing, interconnected by means of grooves not m deep less than 1.5 mm in the covers, and the spacer plate contains through cutouts of the profile corresponding to the profile of the housing channels, at the same time, two through holes are made in one of the liquid radiator covers, each of which is connected by a groove with a depth of at least 1.5 mm channels of the liquid radiator, namely, one hole with its beginning, and the other with its end, moreover, a sealed terminal is mounted in each through hole of the cover, to which a branch pipe is connected, respectively, to one sealed terminal, a branch pipe for supplying coolant, and to another for its besides, a filament supply mechanism is located inside the liquid radiator and wires for connecting to the print head control system pass, at the same time, the sealed terminal includes a sleeve with an external thread on a part of the surface and a union nut connected to it, in which a protruding clamping flange is installed, end part in contact with the end of the sleeve, along with this at the ends of the sleeve and of the clamping flange there is a groove where the ring seal is inserted, at the same time the sleeve is placed motionless in the through hole of the cover and does not extend beyond the groove connecting this hole with the channel system, in addition, in the clamping flange and in the sleeve of the sealed terminal associated with the beginning of the system of channels of the liquid radiator, a holder with holes for the Teflon tube and connection wires is placed, containing channels for the coolant, and the holders are adjacent to each other with the coincidence of the location of the holes and channels, while the holder in the clamping flange is equipped with pin contacts of the connection wires, and the holder in bushing with socket contacts, along with this, each holder is pressed by a seal with holes and channels located corresponding to the holes and channels of the holder, meanwhile the Teflon tube, as well as the wires connecting to the print head control system, are divided into internal and external sections, thus forming contact e groups, each of which is fixed in a holder installed, respectively, for the inner section in the bushing of the sealed terminal, and for the outer section in its clamping flange, and the contact group combines part of the connection wires, and the contact group is located in the branch pipe for supplying coolant, consisting of a Teflon tube and part of the connection wires, also in the spacer plate opposite each sealed terminal there is a through hole into which a plug is inserted, while the plug installed opposite the sealed terminal connected to the coolant supply pipe contains holes corresponding in number and the location of the elements of the contact group passing through the plug, at the same time, the holder seal and the ring seal in the sealed terminal, as well as the plug in the spacer plate, are made of durable elastic material, which prevents the coolant from flowing through the joints with adjacent elements designs.

It should be noted that a common feature with the prototype is the presence of wires for connecting to the print head control system (hereinafter referred to as connection wires). The presence of such wires is confirmed in the description of the prototype by the phrase "Automatic feeding of the filament thread is carried out electromechanically."

The proposed design of the print head for 3D printing with high-temperature polymers (hereinafter referred to as the print head) is illustrated by the following figures.

Fig. 1 is a general view in perspective of the print head with the wires for connecting to the print head control system in two nozzles.

Fig. 2 is a sectional view of FIG. 1 (without nozzles).

Fig. 3 is a perspective view of the printhead of FIG. 2, made with a spatial separation of elements.

Fig. 4 is a perspective view of a liquid cooler housing. The shape and mutual arrangement of the through channels in the walls of the case are shown conditionally.

Fig. 5 is a perspective view of a liquid cooler cover with through holes for the installation of sealed terminals.

Fig. 6 is a perspective view of a liquid heat sink cover without through holes.

Shown in FIG. 5, 6, the grooves connecting in accordance with FIG. 4 through channels in the walls of the housing into a system of channels for the flow of coolant are shown as an example of the organization of a system of channels and can be combined in a different way, depending on the technical requirements for a particular model of the print head.

Fig. 7 is a perspective view of a spacer plate with plug holes.

Fig. 8 is a perspective view of the spacer plate without plug holes.

Fig. 9 is a perspective view of the spacer plate of FIG. 7 with plugs installed, with part of the wires for connecting to the printhead control system in a sealed terminal connected to the end of the liquid cooler duct system.

Fig. 10 is a perspective view of a fragment of a print head made with all the wires connected to the print head control system installed in a sealed terminal connected to the beginning of the liquid radiator duct system.

Fig. 11 is a perspective view of a detail of a printhead made with a portion of the printhead control wiring connected to a sealed terminal connected to the end of the fluid cooler duct system.

Fig. 12 is a perspective view of a sealed terminal bushing with a contact group installed, consisting of connecting wires and a Teflon tube for the filament.

Fig. 13 is a perspective view of a sealed terminal union nut with an attached coolant connection and an installed contact group consisting of connection wires and a Teflon tube for the filament.

Fig. 14 is a perspective view of the cap nut of the sealed terminal of FIG. 13 with a cut through the channels for the coolant and through the hole for the connection wire.

The number of connection wires and channels for the coolant shown in Fig. 10 - 14, as well as their relative position is shown conditionally and depends on the technical requirements for a particular printhead model.

The print head is formed from a filament heating unit and a supply unit feeding the filament to it. The filament moves along the Teflon tube.

The filament heating unit (Fig. 2, 3) contains a high-temperature heating block 1 that transfers heat to the extruder 2 with a nozzle, and a thermal barrier 3. To ensure better heat transfer, it is preferable to use copper as the material of the heating block.

The filament supply unit (Fig. 2, 3) consists of a stepper motor 4 of the Nema 17 type and the actual filament supply mechanism 5, which is used as a widely used standard mechanism, the operation of which is based on pulling the filament clamped between two rotating gears into the heating block and further into an extruder with a nozzle.

To remove excess heat from the extruder nozzle 2, as well as from the heated sealed working chamber (not shown in the figures), in which the print head is installed when printing with high-temperature polymers, the latter is equipped with a liquid radiator 6 (Fig. 2 - 9).

1-Liquid radiator 6 is made in the form of a box formed from a housing 7 (Fig. 4) with a rectangular cross section, closed at the ends with covers 8 (Fig. 5) and 9 (Fig. 6). A spacer plate 10 is installed between body 7 and cover 8 (Fig. 7, 9), and between body 7 and cover 9 there is a spacer plate 11 (Fig. 8). For reliable connection of these elements, screws 12 are used, for example, DIN 912 screws, for installation of which holes 16 are made in the body, covers and spacer plates.

For the flow of the coolant, which can be water, a system of channels is organized in the liquid radiator 6.

For this purpose, through channels 13 are made in the body 7, and grooves 14 are made in the covers 8, 9, while the spacer plates 10, 11 contain through cutouts 15 of the profile corresponding to the profile of the through channels 13 of the body 7.

In addition, two through holes 17 and 18 are made in the cover 8 (Fig. 5) to supply and drain the coolant, and the hole 17 is connected by a groove 19 to one of the grooves 14 to organize the beginning of the channel system, and the hole 18 is connected by a groove 20 to another groove 14 to organize the end of the channel system.

Each of the grooves 14 in the covers 8 and 9, except for the grooves connected to the groove 19 or 20 in the cover 8, combines the through channels 13 in the housing 7 in pairs, while the grooves 14 in the cover 9 combine the through channels 13 with an offset relative to the opposite grooves 14 in lid 8.

The spacer plates 10, 11 adjacent to the covers 8, 9, respectively, having through cutouts 15 around the perimeter, complete the formation of channels for the flow of coolant.

This ensures the sequential flow of the coolant from one channel 13 to another in the housing 7 through the grooves 14 in the covers, while not only the walls of the housing 7 are cooled, but also the covers 8, 9.

For efficient heat transfer, the liquid radiator 6 is made of a material with high thermal conductivity, such as aluminum. The spacer plate can be made of either aluminum or solid rubber or any other material that excludes deformation during operation, leading to leakage of coolant.

The connection of the body 7 with covers 8, 9 and spacer plates 10, 11 with screws 12 creates a solid and reliable structure that prevents leakage of coolant outside the channel system.

To perform in the housing 7 through channels 13, the thickness of its walls should not be less than 4 mm.

The depth of the grooves 14, 19 and 20 in the covers is at least 1.5 mm for the unobstructed flow of the coolant.

It should be noted that the described channel system is not the only possible one. The shape and mutual arrangement of the through channels 13 in the walls of the housing 7 and the grooves 14 in the covers 8, 9 may be different, best suited to the reliability of operation of a particular model of the print head.

In the through holes 17 and 18 of the cover 8, fixedly sealed terminals 24 are installed, which do not protrude within the limits of the grooves 19 and 20, respectively, so as not to impede the flow of the coolant (Fig. 1 - 3, 10, 11). Branch pipes 25, preferably silicone ones, are attached to the sealed terminals 24 (Fig. 1, 10, 11).

The filament feed mechanism 5 and the stepper motor 4 are placed inside the liquid radiator 6 (Fig. 2, 3). This reliably protects them from overheating and associated wear, ensures uninterrupted operation of the entire filament supply unit for a long time at high temperatures, thereby increasing the reliability of the print head.

The heating block 1 and the extruder 2 with a nozzle are installed on the outer lower side of the liquid radiator 6, while the thermal barrier 3 is fixed in the wall of the housing 7 for better heat transfer and heat removal from the filament to its melting point in the heating block 1.

Since the nodes for feeding and heating the filament are located as close as possible to each other, such a negative phenomenon as premature melting of the filament to the melting zone is excluded. This improves the quality of printed products and the reliability of the print head, there is no need to stop the 3D printing process to cool the filament and / or clean the extruder nozzle 2 from clogging.

To ensure the functioning of the mechanical units for feeding and heating the filament, the print head contains wires 21 for connecting to the control system (Fig. 1, 10 - 14).

The connection wires 21, as well as the Teflon tube 22, along which the filament 23 moves, are led inside the liquid radiator 6 through a sealed terminal 24 (Fig. 10) installed in the through hole 17 of the cover 8, and designed to supply coolant through it to the system channels.

Due to the fact that the print head can have a wide range of dimensions, which depends on the size of the printed products and user preferences, then with small dimensions of the print head and, accordingly, reduced dimensions of the hermetic terminals 24, part of the connection wires 21 enter the liquid radiator 6 through the hermetic terminal 24 (Fig. 11), installed in the through hole 18 of the cover 8 and designed to drain the coolant from the channel system. This is due to the fact that it is difficult to place all the connection wires in a small sealed terminal.

Sealed terminal 24 (Fig. 10, 11) is detachable and includes a sleeve 26 (Fig. 12) with an external thread on part of the surface and a union nut 27 attached to the sleeve 26 (Fig. 13, 14). A clamping flange 28 is installed in the union nut 27, part of which protrudes beyond the limits of the union nut 27 for the possibility of connecting the branch pipe 25.

In the end of the sleeve 26 and the end of the clamping flange 28 adjacent to it, there is a groove 29, into which an O-ring 30 is inserted from a durable elastic material, for example, rubber, which prevents leakage of coolant through the junction of the ends of the sleeve and the clamping flange.

A holder 31 is mounted in the clamping flange 28 and in the sleeve 26. Each holder 31 has holes for accommodating connection wires 21, a hole for installing a Teflon tube 22, and channels 32 for the passage of coolant. The holders 31 are adjacent to each other with the coincidence of the arrangement of holes and channels.

Each holder 31 in the sealed terminal 24 is pressed with a seal 33, which has a design similar to the holder 31 and is installed with the coincidence of the location of the holes and channels of the holder 31. The seal 33 is made of a durable elastic material, for example, rubber, it tightly covers the wires 21 passing through it connections and Teflon tube 22, preventing leakage of coolant.

The implementation of a sealed terminal 24 detachable greatly facilitates the maintenance of the print head.

Teflon tube 22 and wires 21 are divided into inner and outer sections and form two contact groups. The contact group of the inner section is fixed in the holder 31 installed in the sleeve 26. The contact group of the outer section is fixed in the holder 31 installed in the clamping flange 28.

Each of the wires 21 for connecting the contact group of the outer section is connected to a pin contact 34, which is mounted in the hole for this wire in the holder 31 installed in the clamping flange 28.

Each of the wires 21 for connecting the contact group of the inner section is connected to the socket contact 35, which is mounted in the hole for this wire in the holder 31 installed in the sleeve 26.

The coincidence in the sealed terminal 24 of the location of holes and channels of the corresponding purpose (hole for Teflon tube 22, holes for accommodating wires 21 connections, channels 32 for coolant) when connecting two contact groups, ensures the installation of pin contacts 34 in socket contacts 35.

When screwing the union nut 27, the connection in the sealed terminal 24 of the two contact groups becomes tight and reliable.

As mentioned above, it is difficult to accommodate all the connection wires in a sealed terminal of small dimensions. Then part of the connection wires 21 enter the liquid radiator 6 through a sealed terminal 24 (Fig. 11) installed in the through hole 18 of the cover 8 and designed to drain the coolant from the channel system. The contact groups of the outer and inner sections in this case will consist only of the connection wires 21, and the hole for the Teflon tube 22 can be used either along with the channels 32 for draining the coolant, or can be closed.

When mounting all wires 21 and Teflon tube 22 in one hermetic terminal 24, associated with the supply of coolant to the radiator 6, in another sealed terminal, associated with the removal of coolant, there is no need for holder 31 and seal 33 mounted in sleeve 26, and they may be missing.

In the spacer plate 10, opposite each sealed terminal, a through hole 36 is made (Fig. 7), into which a plug is inserted from a durable elastic material, for example, rubber to prevent coolant from entering the liquid radiator 6.

For the passage of the connection wires 21 and the Teflon tube 22 inside the liquid radiator 6, the plug 37 (Fig. 9) contains holes corresponding in number and location to the elements of the contact group passing through it.

When installing all wires 21 and Teflon tube 22 in one hermetic terminal 24, associated with the supply of coolant to the radiator 6, the plug 37 opposite the sealed terminal 24, associated with the removal of the coolant, is made without holes (not shown in Fig.).

The plug 37 made of a durable elastic material fits snugly against the spacer plate 10 and tightly covers the connection wires 21 passing through it, the Teflon tube 22, preventing the coolant from leaking into the liquid radiator 6.

Thus, the connection wires 21 and the filament 23 moving along the Teflon tube 22 are protected from overheating when passing through a sealed working chamber with a high temperature, due to their placement in the pipe 25, through which coolant is supplied to the liquid radiator 6.

The placement of part of the connection wires 21 in the pipe for draining the coolant does not adversely affect them, because due to an efficient system for removing excess heat through a system of channels in the liquid radiator 6, the temperature difference between the coolant in the inlet pipe and the liquid outlet pipe is negligible.

Placing wires 21 connections in the pipe together with the coolant is safe, because. an integral part of the wires used in technology is insulation, often supplemented by a protective sheath.

The proposed design of the print head has increased reliability due to:

- an effective system for removing excess heat coming from the heating unit and the sealed working chamber with high temperature through a system of channels in the liquid radiator 6;

- placement of the filament supply unit, respectively, and part of the wires for connecting to the print head control system and the filament, inside the liquid radiator;

- location of the filament supply and heating unit as close as possible to each other;

- placement of connection wires and filament in the pipe with coolant;

- the design of a sealed terminal, which not only facilitates the maintenance of the print head due to its detachable design, but also provides reliable unhindered circulation of the coolant, reliable unhindered movement of the filament along the Teflon tube, as well as quick and safe connection of the print head to the control system.

An effective cooling system increases the wear resistance of the mechanical components of the print head, reliably protects the filament from premature melting to the melting zone. This makes it possible to significantly expand the temperature range for thermoplastic melting upwards, using, among other things, high-temperature polymers such as PEEK and various combinations based on it, as well as increase the time of continuous 3D printing at high temperatures and ensure high quality of printed products.

The proposed device works as follows.

The print head is fixed on the three-coordinate actuator for moving the 3D printer (not shown in the figure). The filament 23, moving along the Teflon tube 22, placed in the nozzle 25, is fed through the sealed terminal 24 to the filament supply mechanism 5, located inside the liquid radiator 6, and then to the heating block 1 and the extruder nozzle 2. After leaving the nozzle, the molten filament 23 is layered is applied to a desktop installed in a sealed working chamber (not shown in the figure) to print the product.

Excess heat generated during the 3D printing process is removed by the coolant circulating in the channel system of the liquid radiator 6. The coolant is circulated by a pump (not shown in the figure).

The coolant enters the liquid radiator 6 through the supply pipe 25 connected to the sealed terminal 24. Through the channels 32 in the holder 31 and the seal 33, the coolant flows into the channel in the cover 8, formed by a groove 19 connected to one of the grooves 14, and a plate - spacer 10. From there, the coolant enters the channel 13 in the housing 7 and then sequentially flows from one channel 13 to another in the housing 7 through the grooves 14 in the covers. After passing through all channels 13, the coolant enters the channel in the cover 8, formed by a groove 20 connected to one of the grooves 14, and a spacer plate 10, from where it flows through the channels 32 in the holder 31 and the seal 33 of the sealed terminal 24, to which it is connected coolant outlet pipe.

After one cooling cycle is completed, the liquid is cooled by a chiller (not shown in the figure) and then the cycle is repeated throughout the entire 3D printing time.

The printhead for 3D printing with high-temperature polymers ensures stable operation at high temperatures, up to 300°C and above, inside the sealed working chamber and a long time of continuous 3D printing.

Claims (1)

A print head for 3D printing with high-temperature polymers, containing an extruder with a heating block, a thermal barrier, a filament feed mechanism, a liquid radiator through which the filament moves along a Teflon tube to the extruder nozzle, wires for connecting to the print head control system, while the heating block and extruder with nozzle installed on the outer lower side of the liquid radiator, characterized in that the liquid radiator is made of a material with high thermal conductivity and has the form of a box formed from a rectangular body with a wall thickness of at least 4 mm, closed at the ends with caps, each of which is attached with screws to the radiator housing through the spacer plate, while the liquid radiator has a system of channels for the coolant, formed from through channels in the housing walls, interconnected by means of grooves with a depth of at least 1.5 mm in the covers, and the spacer plate contains through cutouts for at the same time, two through holes are made in one of the covers of the liquid radiator, each of which is connected by a groove with a depth of at least 1.5 mm to the system of channels of the liquid radiator, namely, one hole - with its beginning, and the other - with an end, moreover, a sealed terminal is mounted in each through hole of the cover, to which a branch pipe is connected, respectively, to one sealed terminal - a branch pipe for supplying coolant, and to the other - for its removal, in addition, a feed mechanism is located inside the liquid radiator filament, and the wires for connecting to the printhead control system pass, at the same time the sealed terminal includes a bushing with an external thread on a part of the surface and a union nut connected to it, in which a protruding clamping flange is installed, the end part in contact with the end face of the bushing, along with this at the ends of the sleeve and the clamping flange there is a groove where the annular seal, at the same time, the sleeve is placed motionlessly in the through hole of the cover and does not extend beyond the groove connecting this hole with the channel system, in addition, a holder with holes for the Teflon tube and connection wires, containing channels for the coolant, and the holders are adjacent to each other with the coincidence of the location of the holes and channels, while the holder in the clamping flange is equipped with pin contacts for the connection wires, and the holder in the sleeve is equipped with socket contacts, along with this each holder is pressed with a seal with holes and channels located corresponding to the holes and channels of the holder, meanwhile the Teflon tube, as well as the wires for connecting to the print head control system, are divided into internal and external sections, forming contact groups, each of which is fixed in the holder, wearily respectively for the inner section in the sleeve of the sealed terminal, and for the outer section - in its clamping flange, and the contact group combines part of the connection wires, and in the branch pipe for supplying coolant there is a contact group consisting of a Teflon tube and part of the connection wires, also, in the spacer plate opposite each sealed terminal, a through hole is made into which a plug is inserted, while the plug installed opposite the sealed terminal connected to the coolant supply pipe contains holes corresponding in number and location to the elements of the contact group passing through the plug, at the same time, the holder seal and the ring seal in the hermetic terminal, as well as the plug in the spacer plate, are made of a durable elastic material, which prevents the coolant from flowing through the joints with adjacent structural elements.

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