Process for printing bone scaffolds based on injection molding 3D printers

Abstract

The application discloses a kind of based on injection molding type 3D printer printing bone support process, belong to bone support preparation technical field, this process first prepares HA / PA66 biological composite material;HA / PA66 composite material is granulated by extruder, and processed into injection molding type granules, then injection molding type granules are dried in oven;Data is input into injection molding type 3D printer by using three-dimensional drawing software to design and draw channel structure to printing component;Injection molding type granules after drying are added into the feeding barrel of 3D printer, activate injection molding unit, set processing area parameter and printing area parameter, and install printing plate;After the stability of each parameter of injection molding type 3D printer, start printing, open hatch after printing is completed, and remove printing component.The process simplifies the processing of raw materials, the selection range of raw materials is wide, the parameters of the printer are controlled, the printing process is controllable, the process stability is good, and the bone support with uniform and porous structure can be prepared.

Description

Technical Field

[0001] This invention relates to the field of bone scaffold fabrication technology, and in particular to a process for printing bone scaffolds using an injection molding 3D printer. Background Technology

[0002] Clinically, bone defects caused by various accidents, tumors, and other diseases require the use of artificial bone scaffolds for bone tissue filling and repair. Currently, metals, bioactive ceramics, and polymers are commonly used as sources of these artificial bone scaffold materials. Metals such as tantalum and titanium have good corrosion resistance and wear resistance, but poor biocompatibility. Bioactive ceramics such as hydroxyapatite and β-tricalcium phosphate have good biocompatibility, but they are brittle and have low strength. Synthetic polymers such as PLGA have excellent mechanical properties and processability, but their degradation rate is uncontrollable, making it difficult to match the bone growth rate, and they also have poor biocompatibility.

[0003] Traditional bone scaffold fabrication methods, such as injection molding, foam impregnation, and phase separation, often employ unstable pore structures and poor pore size uniformity. This results in insufficient bone cell growth and migration after implantation, significantly impacting repair outcomes. 3D printing, also known as additive manufacturing, involves creating a 3D model using computer modeling software, then dividing the model into layer-by-layer sections (slices) to guide the printer. Compared to traditional manufacturing techniques like injection molding, 3D printing eliminates the constraints of molds, allows for customized design, and facilitates efficient manufacturing of polymer products. As the latest molding process, 3D printing is widely used in the fabrication of bone scaffold products, especially for metallic and polymer materials.

[0004] Current polymer 3D printing technologies mostly employ fused deposition modeling (FDM), stereolithography (SLA), and selective laser sintering (SLS). However, FDM printing requires raw materials to be prepared into filaments, which require high precision; SLA printing requires photosensitive resins, which are slightly toxic and pollute the environment; and SLS printing has a long raw material processing time, low surface strength of the molded parts, and also produces certain toxic gases.

[0005] Currently, conventional 3D printing technology is difficult to use for polymer materials with high inorganic filler content, resulting in poor product uniformity and stability, and poor quality control of printed products. Summary of the Invention

[0006] Based on this, the present invention provides a process for printing bone scaffolds using an injection molding 3D printer. This process uses a biocompatible HA / PA66 composite material to prepare a porous scaffold, which combines biocompatibility and good mechanical properties. This process simplifies the processing of raw materials, allows for a wide range of raw material selection, and enables the control of various parameters of the injection molding 3D printer. The printing process is highly controllable and has good process stability, resulting in a bone scaffold with a uniform porous structure. This provides better channels for the growth and migration of bone cells, and compared with traditional injection molding foaming, the bone growth and bone fusion effects are better.

[0007] The technical solution adopted in this invention is:

[0008] A process for printing bone scaffolds using an injection molding 3D printer includes the following steps:

[0009] Step S1. Prepare HA / PA66 biocomposite material;

[0010] Step S2. Granulate the HA / PA66 composite material using an extruder to process it into injection-molded granules;

[0011] Step S3. Dry the injection-molded granules in an oven;

[0012] Step S4. Use 3D drawing software to design and draw the duct structure of the printed component, and input the data into the injection molding 3D printer;

[0013] Step S5. Add the dried injection molding granules into the feeding hopper of the 3D printer, activate the injection molding unit, set the processing zone parameters and the printing zone parameters, and install the printing plate; wherein, in the processing zone parameters, the plasticizing temperature is 250~350℃, and the back pressure is 30~50 bar; in the printing zone parameters, the nozzle temperature is 260~330℃, the melt pressure is 300~500 bar, and the build chamber temperature is 80~200℃.

[0014] Step S6. After the parameters of the injection molding 3D printer have stabilized, start printing. After printing is complete, open the door and take out the printed component.

[0015] In the process disclosed in this application, the preparation method of the HA / PA66 biocomposite material in step S1 is as follows: hydroxyapatite slurry is added to anhydrous ethanol and dispersed evenly to obtain an HA dispersion; CaCl2 and PA66 are added to anhydrous ethanol and heated to dissolve to obtain a PA66 solution; then the HA dispersion and PA66 solution are mixed, precipitated, separated into solid and liquid, washed, dried and granulated to obtain the HA / PA66 biocomposite material.

[0016] In the process disclosed in this application, in step S2, the processing temperature of the extruder is 200~350℃.

[0017] In the process disclosed in this application, in step S2, the extruder is a single-screw extruder or a twin-screw extruder.

[0018] In the process disclosed in this application, in step S3, the drying temperature of the oven is 80~120℃ and the drying time is 8~24h.

[0019] In the process disclosed in this application, the injection molding 3D printer is equipped with an online drying device, which can re-dry the injection molding granules to maintain the continuous drying of the injection molding granules.

[0020] In the process disclosed in this application, the online drying temperature of the online drying equipment is 60~120℃, and the drying flow rate is 10~50L / min.

[0021] In the process disclosed in this application, in step S5, the output amount in the printing area parameters is 50~80%, and the droplet frequency is 100~150Hz.

[0022] In the process disclosed in this application, in step S5, processing zone parameters and printing zone parameters are set. Among the processing zone parameters, the online drying temperature is 110℃, the drying flow rate is 40L / min, the plasticizing temperature is 260℃, and the back pressure is 40bar. Among the printing zone parameters, the nozzle temperature is 320℃, the melt pressure is 400bar, the discharge rate is 70%, the droplet frequency is 140Hz, and the build chamber temperature is 140℃.

[0023] The beneficial effects of the invention are:

[0024] This application uses HA / PA66 biocomposite material as the raw material for the bone scaffold. It exhibits good biocompatibility and provides mechanical strength close to that of human bone. The porous scaffold prepared using this material combines biocompatibility with excellent mechanical properties. Since the uniform porous structure provides better channels for bone cell growth and migration, this application employs an injection molding 3D printer, enabling customized printing of the pore structure. Through parameter control, problems such as uneven pore distribution, structural instability, and poor interlayer adhesion are solved. Compared to traditional injection molding foaming, bone growth and fusion are significantly improved. Furthermore, this process only requires raw materials that meet the dimensions of ordinary injection molding granules, simplifying raw material processing compared to traditional 3D printing. It also offers a wider range of raw material selection, stronger controllability in the printing process, and better process stability. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The bone scaffold prepared in Example 1;

[0027] Figure 2 The bone scaffold prepared in Example 2;

[0028] Figure 3 Electron micrograph of the bone scaffold prepared in Example 2;

[0029] Figure 4 The bone scaffold prepared in Example 3;

[0030] Figure 5 The bone scaffold prepared in Example 4;

[0031] Figure 6 The bone scaffold prepared in Example 5. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0033] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] This application provides a process for printing bone scaffolds using an injection molding 3D printer. The main purpose is to solve the problems of high difficulty in preparing products, poor uniformity and stability of products, and poor controllability of printed product quality caused by conventional 3D printing technology.

[0037] This application discloses a process for printing bone scaffolds using an injection molding 3D printer, comprising the following steps:

[0038] Step S1. Prepare HA / PA66 biocomposite material.

[0039] Step S2. Granulate the HA / PA66 composite material using an extruder to process it into injection-molded granules.

[0040] Step S3. Dry the injection-molded granules in an oven.

[0041] Step S4. Use 3D drawing software to design and draw the duct structure of the printed component, and input the data into the injection molding 3D printer.

[0042] Step S5. Add the dried injection molding granules into the feeding hopper of the 3D printer, activate the injection unit, set the processing zone parameters and printing zone parameters, and install the printing plate. Among them, in the processing zone parameters, the plasticizing temperature is 250~350℃ and the back pressure is 30~50 bar; in the printing zone parameters, the nozzle temperature is 260~330℃, the melt pressure is 300~500 bar, and the build chamber temperature is 80~200℃.

[0043] Step S6. After the parameters of the injection molding 3D printer have stabilized, start printing. After printing is complete, open the door and take out the printed component.

[0044] This application uses HA / PA66 biocomposite material as the raw material for bone scaffolds. It has good biocompatibility and can provide mechanical strength close to that of human bone. The porous scaffolds prepared with it have both biocompatibility and good mechanical properties.

[0045] Because a uniform porous structure provides better channels for bone cell growth and migration, this application uses an injection molding 3D printer, which can achieve customized printing of pore structures. By adjusting parameters, it solves problems such as uneven pore distribution, structural instability, and poor interlayer adhesion. Compared with traditional injection molding foaming, it achieves better bone growth and fusion effects. Furthermore, this process only requires raw materials that meet the dimensions of ordinary injection molding granules, simplifying raw material processing compared to traditional 3D printing, allowing for a wider range of raw material selection, and providing strong controllability and good process stability during printing.

[0046] Specifically, the preparation method of HA / PA66 biocomposite material is as follows: hydroxyapatite (HA) slurry is added to anhydrous ethanol and dispersed evenly to obtain HA dispersion; CaCl2 and PA66 (polyamide 66) are added to anhydrous ethanol and heated to dissolve to obtain PA66 solution; then the HA dispersion and PA66 solution are mixed, precipitated, separated into solid and liquid, washed, dried and granulated to obtain HA / PA66 biocomposite material.

[0047] Specifically, the extruder is a single-screw extruder or a twin-screw extruder, and the processing temperature of the extruder is 200~350℃.

[0048] Specifically, the drying temperature of the oven is 80~120℃, and the drying time is 8~24h.

[0049] Specifically, the injection molding 3D printer is equipped with an online drying device that can re-dry the injection molding granules to keep them continuously dry.

[0050] The drying temperature of the online drying equipment is 60~120℃, and the drying flow rate is 10~50L / min.

[0051] Among the printing parameters, the output rate is 50-80%, and the droplet frequency is 100-150Hz.

[0052] Example 1

[0053] HA / PA66 biocomposite material was prepared. The HA / PA66 composite material was granulated using an extruder to produce injection-molded granules at a processing temperature of 200℃. The injection-molded granules were first dried in an 80℃ oven for 24 hours, then added to the feed hopper of an injection molding 3D printer. An online drying device was used to further dry the granules to maintain continuous drying. The pore structure of the printed component was designed and drawn using 3D drawing software. The data was converted into an STL file and input into the controller of the injection molding 3D printer. The injection unit was activated, and the processing area parameters and printing area parameters were set (see Tables 1 and 2). The printing plate was then installed. After feeding, the printing program was started once the printer parameters stabilized. After printing was complete, the chamber door was opened, the printed component was removed, and the build chamber was closed for a material cleaning procedure. Please refer to [link to relevant documentation]. Figure 1 As shown, the bone scaffold structure printed in this embodiment is stable, has uniform pores, good interlayer adhesion, uniform and complete lines, and is free of breakage.

[0054] Table 1. Processing zone parameters of the injection molding 3D printer in Example 1

[0055]

[0056] Table 2 Printing zone parameters of the injection molding 3D printer in Example 1

[0057]

[0058] Example 2

[0059] HA / PA66 biocomposite material was prepared. The HA / PA66 composite material was granulated using an extruder to form injection-molded granules at a processing temperature of 270℃. The injection-molded granules were first dried in a 100℃ oven for 16 hours, then added to the feeding hopper of an injection-molded 3D printer. An online drying device was used to further dry the granules to maintain continuous drying. The pore structure of the printed component was designed and drawn using 3D drawing software. The data was converted into an STL format file and input into the controller of the injection-molded 3D printer. The injection unit was activated, and the processing area parameters and printing area parameters were set (see Tables 3 and 4). The printing plate was then installed. After feeding, the printing program was started once the printer parameters stabilized. After printing was completed, the chamber door was opened, the printed component was removed, and the build chamber was closed for a material cleaning process. Example 2 is a preferred embodiment of this application. Figure 2 As shown, its bone scaffold structure is stable, with uniform pores, good interlayer adhesion, and uniform, complete lines without fractures. Figure 3 The image shown is an electron microscope image of the bone scaffold, which shows that the scaffold has a complete microstructure, a smooth surface, and no obvious defects.

[0060] Table 3. Processing zone parameters of the injection molding 3D printer in Example 2

[0061]

[0062] Table 4 Printing zone parameters of the injection molding 3D printer in Example 2

[0063]

[0064] Example 3

[0065] HA / PA66 biocomposite material was prepared. The HA / PA66 composite material was granulated using an extruder to produce injection-molded granules at a processing temperature of 350℃. The injection-molded granules were first dried in a 120℃ oven for 8 hours, then added to the feed hopper of an injection molding 3D printer. An online drying device was used to further dry the granules to maintain continuous drying. The pore structure of the printed component was designed and drawn using 3D drawing software. The data was converted into an STL file and input into the controller of the injection molding 3D printer. The injection unit was activated, and the processing area parameters and printing area parameters were set (as shown in Tables 5 and 6). The printing plate was then installed. After feeding, the printing program was started once the printer parameters stabilized. After printing was complete, the chamber door was opened, the printed component was removed, and the build chamber was closed for a material cleaning procedure. Please refer to [link to relevant documentation]. Figure 4 As shown, the bone scaffold structure printed in this embodiment is stable, has uniform pores, good interlayer adhesion, uniform and complete lines, and is free of breakage.

[0066] Table 5. Processing zone parameters of the injection molding 3D printer in Example 3

[0067]

[0068] Table 6. Printing area parameters of the injection molding 3D printer in Example 3

[0069]

[0070] Example 4

[0071] HA / PA66 biocomposite material was prepared. The HA / PA66 composite material was granulated using an extruder to produce injection-molded granules at a processing temperature of 270℃. The injection-molded granules were first dried in a 100℃ oven for 16 hours, then added to the feed hopper of an injection molding 3D printer. An online drying device was used to further dry the granules to maintain continuous drying. The pore structure of the printed component was designed and drawn using 3D drawing software. The data was converted into an STL file and input into the controller of the injection molding 3D printer. The injection unit was activated, and the processing area parameters and printing area parameters were set (see Tables 7 and 8). The printing plate was then installed. After feeding, the printing program was started once the printer parameters stabilized. After printing was complete, the chamber door was opened, the printed component was removed, and the build chamber was closed for a material cleaning procedure. Please refer to [link to relevant documentation]. Figure 5 As shown, the bone scaffold structure printed in this embodiment is unstable, has poor interlayer adhesion, and poor strength.

[0072] Table 7. Processing zone parameters of the injection molding 3D printer in Example 4

[0073]

[0074] Table 8 Printing zone parameters of the injection molding 3D printer in Example 4

[0075]

[0076] Example 5

[0077] HA / PA66 biocomposite material was prepared. The HA / PA66 composite material was granulated using an extruder to produce injection-molded granules at a processing temperature of 270℃. The injection-molded granules were first dried in a 100℃ oven for 16 hours, then added to the feed hopper of an injection molding 3D printer. An online drying device was used to further dry the granules to maintain continuous drying. The pore structure of the printed component was designed and drawn using 3D drawing software. The data was converted into an STL file and input into the controller of the injection molding 3D printer. The injection unit was activated, and the processing area parameters and printing area parameters were set (see Tables 9 and 10). The printing plate was then installed. After feeding, the printing program was started once the printer parameters stabilized. After printing was complete, the chamber door was opened, the printed component was removed, and the build chamber was closed for a material cleaning procedure. Please refer to [link to relevant documentation]. Figure 6 As shown, the bone scaffold printed in this embodiment is severely warped and has poor uniformity.

[0078] Table 9. Processing zone parameters of the injection molding 3D printer in Example 5

[0079]

[0080] Table 10 Printing zone parameters of the injection molding 3D printer in Example 5

[0081]

[0082] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for printing bone scaffolds using an injection-molded 3D printer, characterized in that, Includes the following steps: Step S1. Prepare HA / PA66 biocomposite material; Step S2. Granulate the HA / PA66 composite material using an extruder to process it into injection-molded granules; Step S3. Dry the injection-molded granules in an oven; Step S4. Use 3D drawing software to design and draw the duct structure of the printed component, and input the data into the injection molding 3D printer; Step S5. Add the dried injection molding granules into the feeding hopper of the 3D printer, activate the injection unit, set the processing zone parameters and printing zone parameters, and install the printing plate. Among them, the plasticizing temperature in the processing zone is 250~350℃, and the back pressure is 30~50 bar; the printing zone parameters are: nozzle temperature 260~330℃, melt pressure 300~500 bar, output rate 50~80%, droplet frequency 100~150Hz, and build chamber temperature 80~200℃. Step S6. After the parameters of the injection molding 3D printer have stabilized, start printing. After printing is complete, open the door and take out the printed component. The injection molding 3D printer is equipped with an online drying device, which can re-dry the injection molding granules to maintain their continuous drying. The online drying temperature of the online drying device is 60~120℃, and the drying flow rate is 10~50L / min.

2. The process for printing bone scaffolds using an injection-molded 3D printer according to claim 1, characterized in that, In step S1, the preparation method of HA / PA66 biocomposite material is as follows: hydroxyapatite slurry is added to anhydrous ethanol and dispersed evenly to obtain HA dispersion; CaCl2 and PA66 are added to anhydrous ethanol and heated to dissolve to obtain PA66 solution; then the HA dispersion and PA66 solution are mixed, precipitated, separated into solid and liquid, washed, dried and granulated to obtain HA / PA66 biocomposite material.

3. The process for printing bone scaffolds using an injection-molded 3D printer according to claim 1, characterized in that, In step S2, the processing temperature of the extruder is 200~350℃.

4. The process for printing bone scaffolds using an injection-molded 3D printer according to claim 1, characterized in that, In step S2, the extruder is a single-screw extruder or a twin-screw extruder.

5. The process for printing bone scaffolds using an injection-molded 3D printer according to claim 1, characterized in that, In step S3, the drying temperature of the oven is 80~120℃, and the drying time is 8~24h.

6. The process for printing bone scaffolds using an injection-molded 3D printer according to claim 1, characterized in that, In step S5, the parameters for the processing zone and the printing zone are set. In the processing zone parameters, the online drying temperature is 110℃, the drying flow rate is 40L / min, the plasticizing temperature is 260℃, and the back pressure is 40bar. In the printing zone parameters, the nozzle temperature is 320℃, the melt pressure is 400bar, the discharge rate is 70%, the droplet frequency is 140Hz, and the build chamber temperature is 140℃.

Images