A swirl nozzle for a 3D printer

Abstract

The present invention discloses a swirl nozzle for a 3D printer in the field of 3D printing technology, which includes a housing and two or more inserts. The inserts are arranged inside the housing, and the inserts enclose an internal forming cavity for the passage of plastic materials. Among them, the internal forming cavity has an outlet hole and an inlet hole, and the size of the outlet hole is smaller than that of the inlet hole. One end of the housing has an outlet. The plastic material enters in a solid form at the inlet hole and is discharged in a liquid form through the outlet of the housing at the outlet hole. Both the housing and the inserts are made of heat-conducting materials. The housing is made of heat-conducting materials, and the inserts are also made of heat-conducting materials. The present invention enables the entire nozzle to heat the plastic, improving its plastic melting ability. At the same time, the shape of the consumable can be changed during the melting process to reduce the thickness of the melted plastic, thereby reducing the plastic thermal resistance at the center of the material.

Description

Technical Field

[0001] The present invention belongs to the technical field of 3D printing, and particularly relates to a nozzle for a fused deposition modeling (FDM) 3D printer. Background Art

[0002] 3D printing is a technology that has emerged in recent years. 3D printing, also known as additive manufacturing technology, is a technology for manufacturing solid parts by the method of layer-by-layer material accumulation based on three-dimensional CAD data. From the early rapid prototyping technology to the current wide application, 3D printing technology has been applied in design and manufacturing fields such as jewelry design, footwear design and manufacturing, industrial design, architectural design, engineering design and construction, automotive design and manufacturing, as well as medical fields such as aerospace and dentistry.

[0003] In 3D printing, a commonly used printer is a fused deposition modeling (FDM) 3D printer. For example, a 3D printer disclosed in patent application 202180091464.6 includes: (a) a feeding mechanism, which includes a pushing motor adapted to push a solid filament through a feeding conduit; and (b) a print head, which includes a pulling motor adapted to pull the filament from the conduit and direct the filament to a heating block in fluid communication with a printing nozzle. And the key component in such a 3D printer is the nozzle. In the prior art, patent application 201610385617.9 has disclosed a method for dredging the nozzle of a fused deposition modeling process 3D printer and a device suitable for this dredging method. It includes a nozzle fixing and heating seat for fixing and heating the nozzle, a top screw mechanism for dredging the nozzle of the fused deposition modeling process 3D printer. A resistance heating rod located in the fixed nozzle hole, a temperature controller for temperature control, and a stepper motor controller for controlling the movement of the top screw mechanism.

[0004] Among them, the nozzle is a part of the hot end of the 3D printer. The solid consumable is pushed into the hot end, melted in the nozzle, and deposited onto the target printed part according to the movement of the print head. The nozzle is inserted into the heating block, which contains a heating rod and a temperature sensing element. The 3D printer electronics controls the nozzle temperature through this element, usually between 190 - 300 degrees.

[0005] However, the above-mentioned nozzle still uses the existing structure, relying on an electric heating rod for plastic melting ability, and still needs to be improved. Summary of the Invention

[0006] To solve the above problems, the primary object of the present invention is to provide a swirl nozzle for a 3D printer. Through structural design, the entire nozzle can heat plastic, improve its plastic melting ability. At the same time, the shape of the consumable can be changed during the melting process to reduce the thickness of the melted plastic, thereby reducing the thermal resistance of the plastic at the center of the material.

[0007] Another object of the present invention is to provide a swirl nozzle for a 3D printer. The swirl nozzle can increase the contact area between the nozzle's heat-conducting insert and the plastic material, and is equipped with a swirl channel to mix hot and cold plastic within the nozzle, making the plastic melting temperature more uniform.

[0008] To achieve the above objects, the technical solution of the present invention is as follows.

[0009] A swirl nozzle for a 3D printer includes a housing and two or more inserts. The inserts are arranged inside the housing, and the inserts enclose an internal forming cavity for the passage of plastic material. Among them, the internal forming cavity has an outlet hole and an inlet hole. The size of the outlet hole is smaller than that of the inlet hole. One end of the housing has an outlet. The plastic material enters in solid form at the inlet hole and is discharged in liquid form through the outlet of the housing at the outlet hole. Both the housing and the inserts are made of heat-conducting materials. The housing is made of heat-conducting material and has the feature of installing the nozzle into the heating element of the 3D printer. The inserts are also made of heat-conducting materials. In this way, under the action of the heating element, the nozzle is configured to be connectable to the heating block of the 3D printer, improving the plastic melting ability of the nozzle.

[0010] Further, usually, the 3D printer has a heating element, and the surface of the housing has threads to set the nozzle in the heating element through the threads.

[0011] Further, for the two or more inserts, the side wall of the internal forming cavity formed by them has a concave-convex structure to increase the travel of the plastic material, so that the plastic material can be fully heated, thereby improving the plastic melting ability of the nozzle.

[0012] Furthermore, for the concave-convex structure of the insert, it gradually narrows from the inlet hole to the outlet hole, making the internal forming cavity in a reduced state, facilitating the discharge of the plastic material in liquid form.

[0013] Furthermore, the concave-convex structure is wavy to enable the plastic material in liquid form to move well.

[0014] Further, the insert on the side wall of the internal forming cavity has a first step and a second step. The first step is located at the inlet hole and extends to the middle of the internal forming cavity and connects to the second step. The second step is higher than the first step, and the second step connects to the outlet hole, making the internal space of the internal forming cavity tend to shrink.

[0015] Furthermore, in order to facilitate the entry of solid plastic materials, the first step at the inlet hole has an inclined platform, which enlarges the inlet of the first step.

[0016] Compared with the prior art, the technical effects of the present invention are as follows:

[0017] The swirl nozzle implemented by the present invention improves its plastic melting ability through structural design. At the same time, it can change the shape of the consumable during the melting process to reduce the thickness of the molten plastic, thereby reducing the thermal resistance of the plastic at the center of the material.

[0018] At the same time, the swirl nozzle is equipped with a specially designed insert, which can increase the contact area between the nozzle's heat-conducting insert and the plastic material.

[0019] There is a swirling flow channel between the inserts of the swirl nozzle. Plastic can be pushed into the channel, and hot and cold plastics can be mixed inside the nozzle, making the plastic melting temperature more uniform, thereby improving the plastic melting ability. Description of the Drawings

[0020] Figure 1 is a schematic structural diagram of the swirl nozzle implemented by the present invention.

[0021] Figure 2 is a front view of the swirl nozzle implemented by the present invention.

[0022] Figure 3 is a schematic structural diagram of the insert of the swirl nozzle implemented by the present invention.

[0023] Figure 4 is a schematic diagram of one side structure of the insert of the swirl nozzle implemented by the present invention.

[0024] Figure 5 is a schematic diagram of the other side structure of the insert of the swirl nozzle implemented by the present invention.

[0025] Figure 6 is a cross-sectional view of the insert of the swirl nozzle implemented by the present invention.

[0026] Figure 7 is a cross-sectional view of the insert of the swirl nozzle implemented by the present invention from another angle.

[0027] Figure 8 is an example of the insert of the swirl nozzle implemented by the present invention.

[0028] Figure 9 is a schematic diagram of the principle of the swirl nozzle implemented by the present invention.

[0029] Figure 10 is a schematic diagram of reducing the diameter of the consumable by the swirl nozzle implemented by the present invention.

[0030] Figure 11 This is a schematic diagram of the spiral side channel of the swirl nozzle implemented by the present invention.

[0031] Description of the drawings: 1. Outer shell; 2. Insert; 3. Internal forming cavity; 11 Outer shell outlet; 12. Nut part; 13. Bolt part; 21. Upper insert; 22. Lower insert; 23. Outlet hole; 24. Inlet hole; 211. Second step; 212. First step; 213. Tapered platform. Detailed implementation manners

[0032] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] Figure 1 、 2 As shown, a swirl nozzle for a 3D printer implemented by the present invention includes an outer shell 1 and two or more inserts 2. In the illustration, there are two inserts 2. Among them, the inserts 2 are arranged inside the outer shell 1, and the two inserts 2 enclose an internal forming cavity 3 for the passage of plastic material.

[0034] The internal forming cavity 3 has an outlet hole 23 and an inlet hole 24. The size of the outlet hole 23 is smaller than that of the inlet hole 24. At the same time, one end of the outer shell 1 has an outlet 11, and at the outlet end, there is a nut part 12. The other part of the outer shell 1 is a bolt part 13, that is, the surface of the outer shell 1 has threads, and the threaded part is the bolt part 13. Usually, a 3D printer has a heating element, and the nozzle can be installed in the heating element through the bolt part 13, and the nut part 12 serves to tighten the bolt part 13.

[0035] As Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 shown, the two inserts are an upper insert 21 and a lower insert 22. The upper insert 21 and the lower insert 22 are spliced ​​vertically to form a whole. The internal forming cavity 3 is provided in the upper insert 21 and the lower insert 22. The internal forming cavity 3 is a swirling flow channel, and the swirling flow channel is a narrow channel. Plastic can be pushed into the swirling flow channel and heated and extruded.

[0036] At one end of the two inserts is an inlet hole 24, and at the other end is an outlet hole 23. The plastic material enters in solid form at the inlet hole 24 and is discharged in liquid form through the outlet 11 of the housing 1 at the outlet hole 23; both the housing 1 and the inserts 2 are made of heat-conductive materials; among them, the housing 1 is made of heat-conductive material and has the feature of installing the nozzle into the heating element of the 3D printer, and the insert 2 is also made of heat-conductive material. In this way, under the action of the heating element, the nozzle is configured to be connectable to the heating block of the 3D printer, improving the plastic melting ability of the nozzle.

[0037] Furthermore, as shown in combination with Figure 6 and Figure 7 the side walls of the internal forming cavity formed by the two or more inserts have concavo-convex structures, increasing the travel of the plastic material so that the plastic material can be fully heated, thereby improving the plastic melting ability of the nozzle.

[0038] As shown in combination with Figure 8 taking the upper insert 21 as an example, the inner wall of the upper insert 21 has a concavo-convex structure, and the concavo-convex structure is wavy and gradually narrows from the inlet hole to the outlet hole, making the internal forming cavity in a reduced state, so that the plastic material in liquid form can move well and is convenient for the plastic material to be discharged in liquid form.

[0039] At the same time, at the side wall end of the internal forming cavity, the upper insert 21 has a first step 212 and a second step 211. The first step 212 is located at the inlet hole 24 and extends to the middle of the internal forming cavity 3 and is connected to the second step 211. The second step 211 is higher than the first step 212, and the second step 211 is connected to the outlet hole 23, making the internal space of the internal forming cavity 3 tend to shrink.

[0040] Furthermore, in order to facilitate the entry of solid plastic material, a bevel 213 is provided on the first step 212 at the inlet hole 24, and the bevel 213 enlarges the inlet of the first step, thereby facilitating the entry of the plastic material.

[0041] For the lower insert 22, its structure is the same as that of the upper insert 21 and will not be elaborated here.

[0042] Fourier's law helps to explain heat transfer by conduction in the hot end. Figure 9 As shown, Fourier's law states that the heat flux (Q) is proportional to the area (A) in the normal direction of the heat flow, the temperature difference between the hot end wall and the coldest part of the consumable (core) (T H - T C ), and inversely proportional to the ½ of the filament thickness (r), as shown in the following formula, where the constant k is the thermal conductivity of the plastic.

[0043] Q = k(A / r)(T H - T C )

[0044] The formula reveals several practical methods to increase the heat flow rate, including increasing the temperature of the nozzle, which will cause more plastic to melt and make the melting uncontrollable, so this application does not adopt it; there are also two methods of increasing the surface area between the nozzle and the plastic, or reducing the filament diameter r. In this application, the two methods of increasing the surface area between the nozzle and the plastic and reducing the filament diameter r are adopted, so the heat flow rate can be effectively increased.

[0045] As Figure 10 shown, the melting ability of the nozzle is improved by gradually reducing the diameter r of the consumable, which means that more heat can be transferred to the melted plastic. The consumable is pushed through the channel, and the channel narrows in several stages, thereby increasing the heat transferred to the plastic.

[0046] The figure shows the main central channel shape of a nozzle model, from which the heat transferred to the plastic can be increased.

[0047] Combined Figure 11 as shown, among which, the insert contains processed side channels, and the side channels are preferably spiral, so that the contact area between the nozzle and the melted plastic can be increased. The length of the consumable reaching the nozzle outlet hole will also increase, so that there is more time to transfer heat to the consumable.

[0048] Furthermore, the spiral design directions on both sides of the insert are opposite, which helps to mix the hot and cold consumables and make the filament temperature more uniform.

[0049] In summary, the swirl nozzle realized by the present invention designs a unique insert through structural design. Both the insert and the outer shell are heat-conducting materials, thereby improving its plastic melting ability. At the same time, the shape of the consumable can be changed during the melting process to reduce the thickness of the melted plastic, thereby reducing the plastic thermal resistance at the center of the material.

[0050] At the same time, the swirl nozzle is equipped with a specially designed insert, which can increase the contact area between the heat-conducting insert of the nozzle and the plastic material.

[0051] There is a swirl channel between the inserts of the swirl nozzle. The plastic can be pushed into the channel, and the hot and cold plastics can be mixed in the nozzle, making the plastic melting temperature more uniform, thereby improving the plastic melting ability.

[0052] The above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A swirl nozzle for a 3D printer, characterized in that: It includes a housing and more than two inserts. Inside the housing, the inserts are arranged, and the inserts enclose an internal molding cavity for the passage of plastic material. The internal molding cavity has an outlet hole and an inlet hole, and the size of the outlet hole is smaller than that of the inlet hole. One end of the housing has an outlet. The plastic material enters in a solid form at the inlet hole and is discharged in a liquid form through the outlet of the housing at the outlet hole. Both the housing and the inserts are made of heat-conducting materials. The housing is made of heat-conducting materials. For more than two of the said inserts, the side wall of the internal molding cavity formed by them has a concavo-convex structure, which increases the travel of the plastic material so that the plastic material can be fully heated, thereby improving the plastic melting ability of the nozzle. The insert has a first step and a second step. The first step is located at the inlet hole and extends to the middle of the internal molding cavity and is connected to the second step. The second step is higher than the first step, and the second step is connected to the outlet hole, making the internal space of the internal molding cavity tend to shrink.

2. The swirl nozzle for a 3D printer according to claim 1, characterized in that: The surface of the housing has threads to set the nozzle in the heating element through the threads.

3. The swirling nozzle for 3D printer according to claim 1, characterized in that: The concavo-convex structure of the insert gradually shrinks from the inlet hole to the outlet hole, making the internal molding cavity in a reduced state, which is convenient for the plastic material to be discharged in a liquid form.

4. The swirl nozzle for a 3D printer according to claim 1, characterized in that: The concavo-convex structure is wavy so that the plastic material in liquid form can move well.

5. The swirl nozzle for a 3D printer according to claim 1, characterized in that: The first step at the inlet hole has a bevel, and the bevel makes the inlet of the first step larger.

6. The swirl nozzle for a 3D printer according to claim 1, wherein: The insert includes processed side channels, and the side channels are spiral.

7. The swirl nozzle for a 3D printer according to claim 6, characterized in that: Designing the spiral directions of the two sides of the side channels of the insert to be opposite helps the mixing of hot and cold consumables and makes the wire temperature more uniform.

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