EP3188897A1

EP3188897A1 - Three-dimensional printing hotend and method of fitting such hotend

Info

Publication number: EP3188897A1
Application number: EP15781729.7A
Authority: EP
Inventors: Damian GASIOREK; Grzegorz Kowalczyk; Krzysztof WILK; Przemys aw WOLNICKI; Marcin ZACHWIEJA
Original assignee: Navitracer Polska Sp ZOO
Current assignee: Navitracer Polska Sp ZOO
Priority date: 2014-09-05
Filing date: 2015-09-05
Publication date: 2017-07-12
Also published as: WO2016035057A1

Abstract

The hotend comprise a socket (1) attached to drive unit and printing unit (2). The socket (1) comprises a socket block (3) with channel (4) for the printing unit (2), two parallel fastening rollers (5) set in the socket block (3) and connected with the release button (6), two positioning balls (8), two compression springs (7) and four electrical connectors (9). The printing unit (2) comprises an elongated body (10), heater sleeve (11), lead bush (12), pipe duct (13) and a nozzle (14). The heater sleeve (11) and the lead bush (12) are set in the body (10) and the nozzle (14) is set in the heater sleeve (11). Near end of the body (10) there are recesses (17) for the positioning balls (8). Fitting of the hotend relies on using of a hotend consisting of a socket (1) and the printing unit (2) having a body (10) and a heater sleeve (11) and embedded in this socket (1). A socket block (3) is attached to the hotend drive unit and equipped with a quick holder (4,5,6,7,8) of the body (10) and with set of electrical connectors (9) connected to the printer controller. The body (10) is provided with a hitch (17) for the quick holder (4,5,6,7,8) and with set of electrical connectors (15) interactiong with the set of connectors (9) of the socket (1).

Description

THREE-DIMENSIONAL PRINTING HOTEND

AND METHOD OF FITTING SUCH HOTEND

Technical field

Subject of the invention is three-dimensional printing hotend and method of fitting such hotend to a printer driving mechanism.

Background art

Three-dimensional printing technology concerns the point or layer application of thermoplastic material, so called feed material, through the nozzle of the extruder head that is similar to that known to extrusion technologies. The hotend of a three- dimensional printer is fed with a feed material in solid state, where it passes the heater block and changes it state to be passed on to be extruded through nozzle of a set cross-section that is smaller than the cross-section of the fed material then it reaches the surface of printer table to finally solidify and create a layer of printout. The currently used system of the interconnected components that added to the three-dimensional printer extruder makes quick and easy disassembly of elements requiring cleaning and maintenance operations impossible. The structure of currently available three-dimensional printers includes a replaceable nozzle with constant diameter, designed for certain size of feed material whereas the size of the nozzle influences the thickness of layers that the product - final three- dimensional model is created with. The heating element of the hotend is usually also adjusted to a certain size of feed material. Known extruder hotends of three- dimensional printers are hard to dismantle with a result of costly stoppages in case of e.g. damage of the heater or clogging of the replaceable nozzle. An additional disadvantage of known hotends is their long warm-up time. Disclosure of Invention

The aim of the invention was a hotend that requires to change the state of aggregation of feed material less energy than known hotends, and enabling quick re-tooling for feed material of different size and quick exchange in case of malfunction.

This aim is accomplished by the hotend according to the invention, that comprises a socket attached to a drive unit of the printer and a printing unit. It is characterized by the fact that the hotend socket comprises a socket block and a channel for the printing unit, two parallel fastening rollers slideable mounted in the socket block on both sides of said channel and connected by a release button, two positioning balls, two compression springs, located between the socket block and the release button, and four electrical connectors. The printing unit of the hotend comprises an elongated body with axial opening, heater sleeve, lead bush, pipe duct, nozzle and four electrical connectors. These connectors interact with the four connectors of the hotend socket. First end of the heater sleeve is mounted in first end of the body and the second end of the body holds the lead bush. The second end of the heater sleeve holds the nozzle. The pipe duct is located inside the body and extends from the nozzle to the lead bush. Near the end of the body there are recesses for the positioning balls.

In one of embodiments of the hotend according to the invention outside diameter of the pipe duct of the printing unit is substantially equal to the inside diameters of the heater sleeve and the lead bush. The inside diameter of the axial opening of the body is larger than the outside diameter of the pipe duct. In the axial opening of the body is located an auxiliary tube that surrounds the pipe duct.

In next embodiment of hotend according to the invention outer outline of the body cross-section corresponds to the cross-section of the channel thus ensures unambiguous location of the printing unit in relation to its socket.

In another embodiment of the hotend according to the invention a portion of the body of the printing unit that enters the socket channel is formed as a cuboid with an longitudinal groove on one of its walls. The socket channel is formed as a rectangular hole with a longitudinal protrusion that corresponds to the longitudinal groove of the body. In yet another embodiment of the hotend according to the invention a masking cover that surrounds the heater sleeve is attached to the first end of the printing unit body.

Method according to the invention relies on using a hotend consisting of a socket and a printing unit which is embedded in this socket that consists of body and heater sleeve. To the printing unit are mounted a socket block comprising a quick holder of the body and a set of electrical connectors connected with a printer controller. The body of the printing unit is provided with a hitch for the quick holder and with a set of electrical connectors interacting with the set of connectors of the hotend socket.

In a variant of the method according to the invention the quick holder constitute a channel for the body of the printer unit made in the socket block, two parallel fastening rollers slidably mounted in the socket block on both sides of the channel and connected by a release button as well as two positioning balls and two compression springs, located between the socket block and the release button. The hitch of the body constitute two recesses near the end of the body.

The advantage of the invention is easy and quick dismantling and assembly, of the hotend. Thus the idle time of the printer, resulting from defect or change of feed material, is shortened. The location of heater and the thermistor inside the heater sleeve reduced the amount of energy required for plasticization of feed material and as a consequence - shortened the warm-up time of the hotend. The melting zone is significantly shorter than in currently used solution, and the location of thermistor near the nozzle increases the accuracy of temperature measurement. The hotend accoring to the invention is also significantly lighter than the known hotends, which is of particular importance in case of portable devices. The heater and thermistor form an integral part of the heater sleeve thus eliminating the risk of heater separating from the hotend and resulting in a dangerous breakdown. Replacement of socketed wires with connectors allows for quicker assembly of printing unit in the socket and prevents the risk of cable isolation melt, tear or breaking the cables and resulting short-circuit. Brief Description of Drawings

Embodiment of the invention is presented in the drawing on which fig.1 shows the front view of the hotend, fig.2 shows a top view of the hotend, fig.3 shows a side view of the same hotend, fig. 4 shows a cross-section of the hotend in the horizontal plane marked on fig.3 while fig.5 shows a cross-section in the vertical plane marked on fig.3. Fig. 6 shows the perspective ..exploded" view of the same hotend.

Mode for Carrying out Invention

An exemplary hotend according to the invention comprises a socket 1 and printing unit 2. The socket 1 is permanently fitted to drive unit of the hotend (not shown) and used to removable fitting the printing unit 2. The socket 1 comprises a socket block 3 with a channel 4 and two parallel fastening rollers 5 slideably mounted in the socket block 3 on both sides of the channel 4. Ends of the rollers 5 protruding from the socket block 3 are screwed in a plate release button 6. Each roller 5 is surrounded by a coil compression spring 7 leaning one end on the socket block 3 and other end on the release button 6. Two holers are made in the socket block 3, perpendicular to the axes of the rollers 5, where the positioning balls 8 are placed. The conical ends of the rollers 5 that are located in the area of the socket block 3, when sliding enforce a movement of the locking balls 8 in the direction of the channel 4. A set of four electrical connectors 9 is affixed to the socket block 3 and connected with printer control unit with use of a cable (not shown). The printing unit 2 comprises an elongated body 10 with axial opening, heater sleeve 1 1 , lead bush 12, pipe duct 13 and nozzle 14. First end of the heater sleeve 1 1 is screwed in first end of the body 10 and sealed with Teflon tape (not shown). The lead bush 12 is screwed in the second end of the body 10, and used to introduce feed material to the printing unit 2. The nozzle 14 is screwed in second end of the heater sleeve 1 1. Inside the heater sleeve 1 1 there is a coil of heating resistance wire of the electric heater and the thermistor, covered with ceramic high- temperature mass that prevents corrosion. Both outputs of the heater and thermistor are led out of the the sleeve 1 1 , lead in grooves of the body 10 and connected with two pairs of electrical connectors 15 attached to body 10. The pipe 13 that ducts the feed material in the direction of the nozzle is inserted into the body 10 through the lead bush 12 and resting on the nozzle 14. The outside diameter of the pipe duct 13 is essentially equal to the inside diameters of the heater sleeve 1 1 and the lead bush 12. The inside diameter of the axial opening of the body 10 is larger than the outside diameter of the pipe duct 13. The space so created is filled with auxiliary tube 16 that surrounds the pipe duct 13. Near second end of the body 10 there are two recesses 17. The body 10 has a form of a cuboid with a longitudinal groove 18 along one of its walls. The cross section of the body 10 is adjusted to the cross-section of the channel 4. A longitudinal protrusion 19 on the inside surface of the channel 4 works with the groove 18 of the body 10, which makes the printing unit 2 fit the socket 1 in only one position, that secures electrical connection between the sets of connectors 9 and 15. A masking cover 20 is attached to first end of the body 10 and surrounds the heater sleeve 1 1 .

In order to fit the printing unit 2 in the socket 1 one has to press the button 6, against the force of springs 7. Then the conical sections of rollers 5 will slide, making the balls 8 loose, which will enable the sliding in of the body 10 into the channel 4. After the body 10 is fully inserted the button 6 is released and the released springs 7 will push the rollers 5, which in turn lock balls 8 in the recesses 17 of the body 10. Disassembly of such hotend relies on pressing the button 6 and taking out the printing unit 2. Sets of pipe ducts 13 and auxiliary tubes 16 of different diameters allow for fast adjustment of the hotend to different sizes of feed material.

Claims

1. A three-dimensional printing hotend comprising a socket (1 ) attached to the drive unit and a printing unit (2), characterized in that the socket (1 ) comprises a socket block (3) with a channel (4) for the printing unit (2), two parallel fastening rollers (5) slideably mounted in the socket block (3) on both sides of the channel (4) and connected by a release button (6), two positioning balls (8), two compression springs (7), located between the socket block (3) and the release button (6), and four electrical connectors (9), whereas the printing unit (2) comprises an elongated body (10) with axial opening, heater sleeve (1 1 ), lead bush (12), pipe duct (13), four electrical connectors (14) interacting with the four electrical connectors (9) of the socket (1 ), and a nozzle (14), wherein first end of the heater sleeve (1 1 ) is mounted in first end of the body (10), in second end of the body (10) the lead bush (12) is mounted, in second end of the heater sleeve (1 1 ) the nozzle (14) is mounted, the pipe duct (13) is located inside the body (10) and extends from the nozzle (14) to the lead bush (12) while near the second end of the body (10) there are recesses (17) for the positioning balls (8).

2. The printing hotend according to claim 1 , wherein outside diameter of the pipe duct (13) is substantially equal to inside diameters of heater sleeve (1 1 ) and to inside diameter of the lead bush (12), inside diameter of the axial opening of the body (10) is larger than outside diameter of the pipe duct (13), and wherein an auxiliary tube (16) is placed in the axial opening of the body (10) that surrounds the pipe duct (13).

3. The printing hotend according to claim 1 or 2, wherein the outer outline of the body (10) cross-section corresponds to the cross-section outline of the channel (4) and thus ensures unambiguous location of the printing unit (2) relative to the socket (1 ).

4. The printing hotend according to claim 3, wherein a section of the body (10) that enters the channel (4) is formed as a cuboid with a longitudinal groove (18) on one of its walls, and the channel (14) has the form of an rectangular opening with a longitudinal protrusion (19), that corresponds to the longitudinal groove (18) of the body (10).

5. The printing hotend according to one of claims from 1 to 4, wherein a masking cover (20) surrounding the heater sleeve (1 1 ) is attached to the first end of the body (10).

6. A method of fitting a three-dimensional printing hotend to a drive unit of the hotend characterized in that a hotend consisting of a socket (1 ) and of a printing unit (2) which is embedded in this socket (1 ) is used, the printing unit (2) consists of a body (10) and a heater sleeve (1 1 ), to the printing unit (2) are mounted a socket block (3) comprising a quick holder (4,5,6,7,8) of the body (10) and a set of electrical connectors (9) connected with a printer controller, whereas the body (10) is provided with a hitch (17) for the quick holder (4,5,6,7,8) and a set of electrical connectors (15) interacting with the set of connectors (9) of the socket (1 ).

7. The method according to claim 5, wherein the quick holder constitute a channel (4) for the body (10) of the printer unit (2), located in the socket block (3), two parallel fastening rollers (5) slidably mounted in the socket block (3) on both sides of the channel (4) and connected by a release button (6), two positioning balls (8) and two compression springs (7) located between the side of the socket block (3) and the release button (6), whereas the hitch of the body (10) constitute two recesses (17) near the end of the body (10).