1. The utility model provides an utilize irradiation heating to improve 3D printing system of layer joint strength, its characterized in that, including infrared lamp tube (3), infrared lamp tube (3) are the loop configuration, and the suit is on printer shower nozzle (5) through fixing device (2), and the semi-crystalline polymer material (1) of printing usefulness is preheated through realizing from the center of infrared lamp tube (3), and the secondary heating is realized through infrared lamp tube (3) to printed layer (4) and unprinted layer (6) that set up on base plate (7) of printer shower nozzle (5) below.

2. 3D printing system according to claim 1, wherein the wavelength of the infrared light tube (3) is 2.5-25 μm.

3. 3D printing system according to claim 1, wherein the power of the infrared light tube (3) is 300-1000W.

4. 3D printing system according to claim 1, characterized in that the inner wall of the tube of the infrared light tube (3) is provided with a reflective layer.

5. The 3D printing system of claim 4, wherein the reflective layer is made of a gold or copper material.

6. 3D printing system according to claim 1, characterized in that the fixing device (2) is provided with a cassette of annular configuration, which is movable up and down along the fixing device, the infrared lamp tube (3) being arranged on the cassette.

7. A 3D printing method for improving interlayer connection strength by using irradiation heating, characterized in that, by using the 3D printing system of claim 1, the method comprises the following steps:

s1, fixing the infrared lamp tube with the annular structure on a printer nozzle through a fixing device, and adjusting the height of the infrared lamp tube relative to the substrate;

s2, stretching the sample, slicing the stretched sample, and setting the printing speed, the layer thickness and the printing temperature;

and S3, preheating the printed layer by the infrared lamp tube, starting printing, and after the printer nozzle finishes printing at one point, continuing heat preservation treatment on the unprinted layer by the infrared lamp tube to finally print the sample with good interlayer bonding strength.

8. The method of claim 7, wherein in step S1, the distance between the infrared lamp and the substrate is 10-20 cm.

9. The method according to claim 7, wherein in step S2, the printing speed is 40-60 mm/S, the layer thickness is 0.1-0.4 mm, and the printing temperature is 200-420 ℃.

10. The method according to claim 7, wherein the preheating temperature of the printed layer in step S3 is 100-200 ℃.

Background

3D printing has been widely used in the fields of biomedical, aerospace, and automotive manufacturing as an advanced manufacturing technology that has been rapidly developed in recent years. The most common low-cost printing method in the 3D printing method is the melt extrusion molding method, which mainly comprises heating a continuous filament material through a nozzle to a semi-liquid state, and then extruding the heated continuous filament material onto a platform or a previous printing layer. The main advantages of the melt extrusion molding method are that the cost is low, the printing speed is high, the printing process is relatively simple, but due to the inherent strong anisotropy of the method, the bonding force between layers of the printing piece in the printing direction is obviously weaker than that in other directions, namely for semi-crystalline polymer materials, after the semi-crystalline polymer materials are heated and extruded by a heating block, the materials are rapidly cooled and solidified, so that the diffusion time of polymer molecular chains between adjacent layers is limited, the materials between the layers cannot be well bonded, the bonding strength of the melt deposition materials in the deposition direction cannot be ensured, and the mechanical property of the printing piece is changed along with the difference of the directions.

At present, a common method for improving interlayer connection strength of a melt extrusion molding method is to utilize laser to perform precise preheating, and the method mainly utilizes heat generated by laser preheating to promote the movement of molecular chains and reduce the temperature difference between a deposited layer and a printed layer, so that effective combination is formed between the layers, and higher connection strength is obtained. Although the laser heating has good precision and high heating efficiency, the whole system is complicated; the cost is high; the most critical point is that when the laser is used for preheating, the relative position of the whole laser preheating device and the melt extrusion molding spray head is kept unchanged, that is, the laser preheating position is not switched along with the switching of the printing path, and only when the printing head prints towards a certain fixed direction, a good preheating effect can be achieved, therefore, the situation that the laser can not preheat in advance in the process of printing the same layer inevitably exists, so that the connection strength at different positions among the layers is uneven, and for high melting point semi-crystalline polymer materials, the temperature of the printing material at the nozzle is much different from the ambient temperature, this causes the material to dissipate quickly after just finishing printing, and the material between layers does not have enough time to finish diffusing, resulting in lower bonding strength between layers, which is also a problem to be solved in order to improve the bonding strength between layers at present.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a 3D printing system and method for improving interlayer connection strength by irradiation heating in melt extrusion molding, which can ensure the effect of preheating the printed layer before printing and preserving heat of the printed layer after printing is completed, and effectively improve the interlayer connection strength of the printed product.

The invention adopts the following technical scheme:

the utility model provides an utilize irradiation heating to improve 3D printing system of layer joint strength, includes infrared lamp tube, and infrared lamp tube is the loop configuration, and through fixing device suit on the printer shower nozzle, the semi-crystalline polymer material of printing usefulness preheats through realizing from the center of infrared lamp tube, and the layer of having printed and the not layer of printing that set up on the base plate of printer shower nozzle below realize the secondary heating through infrared lamp tube.

Specifically, the wavelength of the infrared lamp tube is 2.5-25 μm.

Specifically, the power of the infrared lamp tube is 300-1000W.

Specifically, the inner wall of the lamp tube of the infrared lamp tube is provided with a reflecting layer.

Furthermore, the reflecting layer is made of gold or copper material.

Specifically, the fixing device is provided with a clamping seat of an annular structure, the clamping seat can move up and down along the fixing device, and the infrared lamp tube is arranged on the clamping seat.

Another technical solution of the present invention is a 3D printing method for improving interlayer connection strength by irradiation heating, using the 3D printing system, comprising the steps of:

s1, fixing the infrared lamp tube with the annular structure on a printer nozzle through a fixing device, and adjusting the height of the infrared lamp tube relative to the substrate;

s2, stretching the sample, slicing the stretched sample, and setting the printing speed, the layer thickness and the printing temperature;

and S3, preheating the printed layer by the infrared lamp tube, starting printing, and after the printer nozzle finishes printing at one point, continuing heat preservation treatment on the unprinted layer by the infrared lamp tube to finally print the sample with good interlayer bonding strength.

Specifically, in step S1, the distance between the infrared lamp and the substrate is 10-20 cm.

Specifically, in step S2, the printing speed is 40-60 mm/S, the layer thickness is 0.1-0.4 mm, and the printing temperature is 200-420 ℃.

Specifically, in step S3, the preheating temperature of the printed layer is 100 to 200 ℃.

Compared with the prior art, the invention has at least the following beneficial effects:

the invention relates to a 3D printing system for improving interlayer connection strength by utilizing irradiation heating, wherein an infrared lamp tube is of an annular structure and is sleeved on a printer nozzle through a fixing device, a semi-crystalline high-melting-point polymer material for printing is preheated through the center of the infrared lamp tube, and a printed layer and an unprinted layer arranged on a substrate below the printer nozzle realize secondary heating through the infrared lamp tube; through preheating before printing and heat preservation after printing, reduced the difference in temperature between the layer of having printed and the printing layer, can improve the joint strength between the layer effectively.

Furthermore, the infrared lamp tube is made into a ring shape and sleeved on the 3D printing nozzle, so that the whole layer of material can be uniformly preheated in the printing process and is not limited by the printing direction.

Furthermore, the wavelength of the ring-shaped infrared lamp tube is selected according to the infrared spectrogram of the preheated material and the difficulty of different materials for absorbing energy with different wavelengths.

Furthermore, the power of the infrared lamp tube is set to be 300-1000W, and different semi-crystalline polymer materials can be softened.

Furthermore, the reflecting layer is arranged on the inner wall of the lamp tube, so that the utilization rate of infrared rays emitted by the lamp tube can be improved, and the excessive consumption of energy is avoided.

Furthermore, the reflecting layer is made of materials such as gold, copper and aluminum, so that the reflectivity of infrared rays can be improved, and the utilization rate of the infrared rays can be effectively improved.

Furthermore, the distance between the lamp tube and the substrate can be easily changed by arranging the clamping seat with the annular structure.

According to the method for improving the interlayer connection strength by using the mode that the annular heating lamp tube preheats and preserves heat of the printing material in the printing process, the annular heating tube is fixed on the printing nozzle and can move along with the printing nozzle, and the printed layer can be always preheated before the next layer is printed regardless of the change of the printing path, so that the temperature difference between layers is reduced, and the interlayer connection strength can be effectively improved; meanwhile, after the wire is extruded by the nozzle, the annular heating pipe can still heat the wire which is just printed out, so that the heat preservation effect is achieved for a period of time, and the interlayer connection can be effectively improved on the basis of the previous preheating.

Furthermore, the annular infrared lamp tube and the substrate should be kept in parallel, and the wavelength of the infrared lamp tube is selected according to the infrared spectrogram of the preheated material, so that the infrared absorption of the material is facilitated, and the required temperature is reached in a short time.

Furthermore, the printing temperature, the printing speed and the layer thickness are set, the influence of the printing temperature, the printing speed and the layer thickness on the interlayer connection strength is the largest, and more ideal experimental results can be obtained by selecting appropriate parameters.

Furthermore, the preheating temperature is set to be 100-200 ℃, so that the glass transition temperature of the semi-crystalline polymer material is generally within the range, and the semi-crystalline polymer material can be softened when the preheating temperature is higher than the glass transition temperature, and the entanglement among polymer molecular chains is improved.

In conclusion, the invention fixes the annular heating lamp tube on the spray head, and moves along with the spray head, and the printed layer can be preheated before the next layer is printed no matter how the printing path is changed, thereby effectively improving the connection strength between the layers; meanwhile, after the wire is extruded by the nozzle, the annular heating pipe can still heat the wire which is just printed out, so that the heat preservation effect is achieved for a period of time, and the interlayer connection can be effectively improved on the basis of the previous preheating.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

Wherein: 1. a semi-crystalline polymeric material; 2. a fixing device; 3. an infrared lamp tube; 4. a printed layer; 5. a printer head; 6. an unprinted layer; 7. a substrate.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "one side", "one end", "one side", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. In addition, in the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

It is also to be understood that the terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in the specification of the present invention and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

Various structural schematics according to the disclosed embodiments of the invention are shown in the drawings. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.

The invention provides a method for improving interlayer connection strength by utilizing irradiation heating, which comprehensively considers the factors of energy loss, preheating efficiency, device complexity and the like of the existing preheating method and provides a 3D printing system capable of effectively improving interlayer connection strength.

Referring to fig. 1, the 3D printing system includes a fixing device 2, an infrared lamp tube 3, a printer head 5 and a substrate 7, the fixing device 2 is disposed on the printer head 5, the infrared lamp tube 3 with an annular structure is fixedly connected to the fixing device 2, the infrared lamp tube 3 is sleeved on the printer head 5, the semi-crystalline polymer material 1 for printing is preheated through passing through the center of the infrared lamp tube 3 with the annular structure, and a printed layer 4 and an unprinted layer 6 disposed on the substrate 7 under the printer head 5 are heated secondarily through the infrared lamp tube 3. For the melt extrusion molding method, the core difficulty lies in that the connection strength between layers is insufficient in the printing process, because the temperature of the material extruded by the spray head is higher, compared with the ambient temperature, a larger temperature difference is formed, so that the temperature of the extruded material is rapidly reduced in a short time, and the temperature of the printing material plays a key role in improving the connection strength between the layers, the infrared lamp tube 3 with the annular structure adopted in the invention can preheat the deposited layer before the deposition of the printing spray head 5, and improve the temperature of the deposited layer material to the temperature which is beneficial to realizing the entanglement of the material between the layers, so as to improve the connection strength between the layers, after the material is deposited on the printed layer, the infrared lamp tube 3 secondarily heats the printed layer to slow down the temperature reduction speed of the printing material, so as to secondarily improve the connection strength between the layers, a test piece having a desired interlayer connection strength was obtained.

Fixing device 2 includes the bolt, is provided with the cassette on the bolt, and the cassette can reciprocate along the bolt, and infrared lamp tube 3 sets up on the cassette, fixes and adjusts infrared lamp tube 3 and prints the distance between the layer through the cassette.

Performing infrared spectroscopic analysis on the semi-crystalline polymer material 1 to obtain an infrared spectrogram of the semi-crystalline polymer material 1, observing the infrared spectrogram to obtain a wavelength of 2.5-25 mu m of an absorption peak of the semi-crystalline polymer material 1, and determining the glass transition temperature of the semi-crystalline polymer material 1; setting the wavelength of the infrared lamp tube 3 to be 2.5-25 μm; the infrared lamp tube 3 with power of 300-1000W can heat the material to the glass transition temperature of the semi-crystalline polymer material within 1-2 s.

Considering preheating efficiency and irradiation area's size to the influence of printing the layer, the fluorescent tube upper surface coating of the infrared ray fluorescent tube 3 of annular structure has one deck reflection stratum, and the reflection stratum adopts gold or copper, and the energy of the up irradiation of infrared ray fluorescent tube 3 passes through the reflection stratum reflection to printed layer 4 on, can give the effect of effectively playing reflection infrared ray, can play the focus facula simultaneously, the effect of accurate heating.

The invention relates to a method for improving interlayer connection strength by utilizing irradiation heating, which comprises the following steps:

s1, fixing the infrared lamp tube 3 with the annular structure on a printer nozzle 5 through a fixing device 2, and adjusting the position of the infrared lamp tube 3 relative to the substrate 7 to be 10-20 cm, so that the printed layer 4 reaches a glass transition temperature after being preheated;

s2, printing a standard tensile sample by using GB 16421-;

s3, in the printing process, the infrared lamp tube 3 firstly preheats the printed layer 4, the temperature difference between the printed layer 4 and the unprinted layer 6 is reduced, mutual diffusion of molecular chains between the two layers is promoted, after the printer nozzle 5 finishes printing at one point, the infrared lamp tube 3 continues to carry out heat preservation treatment on the unprinted layer 6, the cross-linking time between the printed layer 4 and the unprinted layer 6 is prolonged, and finally a sample with good interlayer bonding strength is printed.

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Take the semi-crystalline high melting point polymer material PEEK printing standard tensile test sample as an example.

1) Performing infrared spectrum analysis on the PEEK material to obtain an infrared spectrogram of the PEEK material, wherein the range of infrared wavelengths easily absorbed by the PEEK material is 5.6-12.5 mu m, the range is also included as far as possible by the wavelength of a selected annular infrared lamp tube, and the glass transition temperature of the PEEK material is 143 ℃, so that the power of the selected annular infrared lamp tube is required to be satisfied for heating the material to 150-200 ℃ in a short time; by coating a layer of coating, such as gold or copper, on the inner wall of the lamp tube, the effect of reflecting infrared rays can be effectively achieved, and meanwhile, the effects of focusing light spots and accurately heating can be achieved;

2) fixing the selected annular infrared lamp tube on a jet head of an FDM printer through a fixing device, and adjusting the position of the annular infrared lamp tube relative to the substrate to enable the printed layer to reach the glass transition temperature of the PEEK material after being preheated;

3) the method comprises the steps of printing a standard tensile sample by GB 16421-.

In the printing process, the annular infrared lamp tube preheats the printed layer firstly, the temperature difference between the printed layer and the next layer can be obviously reduced in the process, mutual diffusion of molecular chains between the two layers is promoted, after the nozzle finishes printing at one point, the annular infrared lamp tube continues to carry out heat preservation treatment on the printed layer, the cross-linking time between the layers is prolonged, and finally a sample with good interlayer bonding strength is printed.

In summary, according to the method for improving interlayer connection strength by irradiation heating, the annular heating pipe is fixed at the nozzle of the FDM printer, so that when the nozzle performs printing in any direction, preheating of a previously printed layer can be guaranteed, the temperature difference between the printed layer and the printed layer is reduced, and bonding between the two layers is facilitated; and for the wire material just deposited, the annular heating pipe can continue to heat the wire material, so that a heat preservation effect is achieved, the interlayer adhesion is further improved, and the structure with good interlayer connection strength is favorably manufactured.

The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.