WO2022252689A1

WO2022252689A1 - Manufacturing method based on 3d printing and injection molding

Info

Publication number: WO2022252689A1
Application number: PCT/CN2022/076285
Authority: WO
Inventors: 周应国; 杨金强; 孙弘龙
Original assignee: 江苏科技大学
Priority date: 2021-06-03
Filing date: 2022-02-15
Publication date: 2022-12-08
Also published as: CN113510938A; CN113510938B

Abstract

Disclosed are a manufacturing method based on 3D printing and injection molding, comprising: performing structural design on a 3D printed part, and completing the processing of the 3D printed part; preheating the 3D printed part and then putting same into a corresponding position of an injection mold; injecting a thermoplastic polymer raw material into the injection mold, cooling and then shaping the material, so that the 3D printed part and the injected polymer raw material form a uniform combined part; and post-processing the obtained combined part for warping and stress distribution to obtain a product. According to the present invention, a combined part of which one or more aspects of mechanical properties, conduction properties or other service properties are superior to those of a common injection product can be obtained, and the manufacturing process is good in repeatability, high in practicability and suitable for batch production.

Description

A manufacturing method based on 3D printing and injection molding

technical field

The invention relates to a molding method, in particular to a manufacturing method based on 3D printing and injection molding.

Background technique

3D printing technology is also known as additive manufacturing technology, referred to as 3D printing. It is based on the idea of discrete/accumulation, and uses computer software to process the CAD 3D model of the product in layers along a certain direction to obtain the processing information of the cross-sectional profile of each layer. , through the layered processing of the 3D printer, layer by layer superimposition, quickly and accurately transform the design concept into a prototype with certain functions or directly manufacture parts. Due to the advantages of quickly obtaining design product prototypes and breaking through difficult-to-process parts in traditional manufacturing, 3D printing technology has increasingly become the focus of attention in many industries, and its applications are also expanding.

However, the current production efficiency of 3D printed parts is often low, especially when 3D printing is used to process similar injection molded parts, it still does not have the possibility of mass production; at the same time, the stability of mechanical properties of 3D printed parts Relatively low, which adds some limitations to its application in processing large parts.

Contents of the invention

Purpose of the invention: The purpose of the present invention is to provide a manufacturing method based on 3D printing and injection molding, which can obtain one or more aspects of mechanical properties, conductivity properties or other performance properties that exceed the combined parts of ordinary injection products, and manufacture The process has good repeatability and strong implementability, and is suitable for mass production.

Technical solution: A manufacturing method based on 3D printing and injection molding described in the present invention comprises the following steps:

(1) Design the structure of the 3D printed parts and complete the processing of the 3D printed parts;

(2) Preheat the 3D printed part and put it into the corresponding position of the injection mold;

(3) Fill the thermoplastic polymer raw material into the injection mold, and after cooling, the 3D printed part and the polymer raw material injected after injection form a uniform composite part;

(4) After the warpage and stress distribution are performed on the obtained combined parts, it is obtained.

According to the characteristics and application purposes of the injection products to be processed, the invention specially designs the processed 3D printed parts as in-mold inserts of the injection products, and finally forms a product processing method in which the 3D printed parts and the injection melt are integrated.

Among them, in the above step (1), the use target of the part includes the improvement of mechanical properties, electrical properties, etc.; analyze the structure of the injection part to be processed, determine its characteristics and use targets, and then determine the 3D printing production target. The embedding position, size and shape characteristics of the parts are used to carry out the structural design of the 3D printed parts.

Further, the structural design of the 3D printed part includes its own structural reinforcement part, in-mold placement part and melt flow control part; wherein, the self-structural reinforcement part mainly ensures the strength of the printed part itself. As a preference, the self-reinforcing part guarantees The mold cavity does not deform when subjected to a pressure of 0 to 50 MPa. The placement part in the mold is mainly for easy placement when placed in the mold to ensure that its position is fixed when the mold is opened and closed. It is 0.5% to 2 larger than the size of the corresponding position of the mold cavity. %, the melt flow control part is the functional part of the 3D printing part, which is mainly consistent with the flow direction of the melt during the injection process. As a preference, the melt flow control part is consistent with the flow direction of the melt in the mold Parallel to each other, thus showing an effect similar to a slender flow channel.

Among them, the size of the placement part is larger than the size of the corresponding position of the mold cavity to ensure that the 3D printed part is placed in the mold and can be placed in the mold under a slight force. If the size is too small, the fixation will not be firm, and if the size is too large, it will be difficult to install. The design principle of the melt flow control part is: through the restricted flow of the melt in the specified direction, the flow induction effect is improved, and then the mechanical properties of the filled melt are improved. In addition, the overall performance of the final product can be improved by improving the interfacial bonding between the post-filled melt and the pre-placed insert.

Preferably, the melt flow control part of the 3D printed part is a slender flow channel, or a micro-groove is provided on the inner wall surface of the slender flow channel; the usual practice of such micro-grooves is to design and print directly on the 3D printed part, But this will add trouble to the corresponding printing control. As an improved method in this application, the micro-grooves are obtained by modifying the original code during the printing process and obtaining more random stop points.

In the above step (2), the preheating temperature of the 3D printed part is between 5 and 20 degrees lower than its heat distortion temperature, and the temperature difference between the preheating temperature and the injection mold is between 0 and 80 degrees. Wherein, the temperature of the injection mold may be constant, or a process of variable mold temperature may be adopted.

The preheating temperature ensures that the material can be slightly deformed when it is placed, which is convenient for placement. At the same time, the temperature difference between the preheating temperature and the plastic melt after filling is as small as possible to ensure that the difference in shrinkage between the two is the smallest. However, preheating The temperature should not be too high. When it exceeds or approaches the thermal deformation temperature, the strength of the printed part to withstand the injection will be affected, and deformation will occur during injection, which will affect the appearance and performance of the final product.

In the above step (4), special post-processing is carried out on the obtained composite part to avoid warping of the product and eliminate its internal stress. Specifically, the post-processing includes placing the workpiece in a jig matching the shape of the workpiece, and keeping it at a temperature 10-20 degrees lower than the melting point for 5-20 minutes.

Preferably, the melt flow regulation part of the 3D printed part is provided with elongated channel micro-grooves.

Furthermore, the interface properties of dissimilar materials need to be considered, and corresponding means can be used to improve the interface bonding effect between dissimilar materials. The 3D printing method of the present invention that can be used for injection molding inserts, in order to improve the melting point between 3D printed parts and post-injection During the printing process, there are many random stop points, and the stop time is between 1 and 1000ms. Each stop point forms a micro-gully on the printed piece.

In order to increase the stop points in the printing process, the present invention also provides a method for directly modifying the printing code. Mainly include the following steps: (1) determine the interval distance of the stay points; (2) determine the number of interval points according to each print segment; (3) determine the position of each interval point; (4) modify the code of the print segment and insert N stays Click the code, and modify the amount of printing materials synchronously.

For example, taking the dwell time as 200ms as an example, there is the following code in the printing process:

...

G1 X35.783 Y11.081 E13.44863//print from (***,***) to (35.783,11.081); E represents the total amount of printing filament (the same below);

G1 X63.132 Y11.081 E13.77165 //Continue printing to (63.132, 11.081)E increments represent the amount of printing materials;

...

The content of "//" is the explanation part.

Then, when there is a P point (35.783, 11.081) in its printing path, the typical code when staying at this point is as follows:

...

G1 X49.458 Y11.081 E13.61014//The increment from (35.783, 11.081) to (49.458, 11.081) E indicates the amount of printing material;

G4 P200 //Stay at point P (49.458, 11.081) for 200MS

G1 X63.132Y11.081 E13.77165//continue to print to (63.132, 11.081)

...

The resulting article of the invention has an insert manufactured using 3D printing. Among them, 3D printing and injection molding can use the same material or different materials. The process used for 3D printing products can be one or a combination of FDM, SLS, POLYJET, MJF, SLA and other processes.

The present invention also provides a specific application of the above-mentioned combined product of 3D printing and injection molding, which has advantages in one or more aspects of mechanical properties, electrical conductivity, and thermal conductivity.

The principle of the invention: the invention uses the characteristics of the 3D printed parts to flexibly design the structure of the part, and designs a structure that facilitates the filling of the melt in the cavity and maintains the orientation, so as to realize the performance control of the polymer injection molding product in part or all spaces . At the same time, the method of using the stop point will add a small amount of raw materials to the material at the position of the stop point, thereby increasing the interface bonding between the filling melt and the printed part,

Although injection molding has high production efficiency and can process products with complex shapes, it can be applied not only to thermoplastics, but also to thermosetting plastics. Therefore, products processed by this process are widely used, and it is currently one of the industrial production methods for plastic products. a common process. However, injection molding is also often faced with the need for local reinforcement of parts, improvement of mechanical properties or conductivity.

The combination of 3D printing and injection molding has the following technical difficulties: when the 3D printed parts are put into the injection mold and then injected and filled, they will also face a series of problems, and the 3D printed parts cannot be placed in the injection mold well. Internal; when the pressure of injection filling is high, the 3D printed part may not be able to bear it and cause severe deformation; the interface between the 3D printed part and the post-filled melt is poor; Parts are prone to warping, etc.

The present invention provides a method for combined manufacturing of 3D printing and injection molding, which comprehensively solves the problems faced when using this method for combined manufacturing. , the design of related devices and molds, etc., to obtain one or more aspects of mechanical properties, conductivity or other performance properties that exceed the combined parts of ordinary injection products. This process has good repeatability and strong implementability, and is suitable for batch production. chemical production.

The method of combining 3D printing and injection molding of the present invention has the following beneficial effects:

(1) It can easily combine the advantages of the two processing methods of 3D printing and injection molding, and has broad application prospects in improving the mechanical properties, thermal conductivity or electrical conductivity of the product in whole or in part;

(2) The production can be realized by using ordinary equipment, using a mold that is exactly the same as ordinary injection products, and there is no need to modify or adjust the mold structure, so the process is simple and convenient to implement;

(3) The interfacial bonding force between dissimilar materials is effectively improved, and the consistency of the product is good;

(4) Effectively solve the problems that are easy to occur when 3D printing parts are placed and fixed on the injection mold, and the warping problems that are easy to occur when 3D printing and injection molding combined parts are easy to occur;

(5) The added stop points in the printing process may not be reflected in its structural design. These stop points are formed by directly modifying the code later, and the positions are randomly distributed, so that there will be no hindrance to the flow of the melt on a macro level effect, and will not affect the structure of the print itself.

(6) The design method and code improvement method of the corresponding 3D printed parts in the present invention, the products that use the above methods to control the polymer injection flow process, the mechanical properties and electrical properties of the products obviously surpass similar products.

Description of drawings

Fig. 1 is technological process schematic diagram of the present invention

Fig. 2 is a schematic diagram of the process route of the present invention.

Fig. 3 is a design drawing of the 3D printing part of the present invention.

Fig. 4 is an outline view of the 3D printed part obtained in Example 1 of the present invention, that is, a 3D printed insert in the form of micro-grooves.

Fig. 5 is an outline view of the 3D printed part obtained in Example 2 of the present invention, that is, the 3D printed insert without grooves.

Fig. 6 is an outline view of the part of Comparative Example 1, which has a 3D printed insert in the form of a macroscopic ravine.

Fig. 7 is the outline drawing of the workpiece of Comparative Example 2, a grid-like printed part.

Figure 8 is the product obtained after the 3D printed part is filled with PP material; Among them, Figure A is the product of Comparative Example 1, which has serious warping without preheating and post-treatment; Figure B is the product of Comparative Example 1 Part, the part has been preheated, but not post-treated, and the warpage is slightly better; Figure C is the part of Example 1, and the warpage is completely eliminated.

Fig. 9 is a scanning electron micrograph of the cross-sectional structure of the product of the embodiment of the present invention.

Fig. 10 is a scanning electron micrograph of a cross-sectional structure of a comparative product.

Detailed ways

The present invention will be further described in detail below in conjunction with the examples.

The 3D printing and injection molding combined manufacturing method described in the present invention mainly includes three key technical details of preliminary preparation, molding process, and post-processing. In terms of equipment, an ordinary injection machine and 3D printer are required; the injection raw material used is thermoplastic resin, and the 3D printing raw material is determined according to its corresponding process, and the raw and auxiliary materials used are all commercially available.

As shown in Fig. 1, 2 is technological process and route schematic diagram of the present invention, and main realization step of the present invention comprises the following steps:

(1) Analyze the structure of the injection part to be processed, determine its characteristics and use goals, and then determine the embedding position, size and shape characteristics of the 3D printed part, and carry out the structural design of the 3D printed part;

(2) Modify the 3D printing source code and complete the processing of the 3D printing parts;

(3) Preheat the 3D printed part and put it into the corresponding position of the injection mold;

(4) Fill the thermoplastic polymer raw material into the injection mold, and after cooling, the 3D printed part and the polymer raw material injected after injection form a uniform combined part;

(5) After post-processing the warpage and stress distribution of the obtained composite parts, products with excellent mechanical properties, or special conduction properties, or special control effects can be obtained.

Example 1 PC/ABS-FDM-micro-grooves+PP

In this example, PC/ABS is used as the raw material for 3D printing, and PP is used as the raw material for injection. Among them, the tensile strength of PP is 27.5MPA, the Young's modulus is 1099MPa, and the tensile strength of PC/ABS printed parts is 45.7MPa. The modulus is 1975MPa. The 3D printing process used is FDM. Its implementation process is as follows:

Firstly, carry out the structural design of the 3D printed part. The design process is shown in Figure 3. According to the characteristics of the standard tensile spline to be processed, the structure of the 3D printed part mainly includes three parts, the bottom part is fixed to the mold, Its width is controlled at 10.1mm, the end reinforcement part, the width is 10mm, and the elongated flow channel part, its cross-sectional part accounts for 40% of the cross-sectional volume of the entire injection part (including the bottom fixed part); the printed part is shown in Figure 4 Among them, the left part of the part is the self-reinforcing part, the lower part of the part is the placement part in the mold, and the upper right part of the part is the melt flow control part, and there are fine grooves in the melt flow control part.

Secondly, according to the designed model, the software automatically generates the 3D printing source code. On this basis, the 3D printing source code is modified, and the stop point is enhanced during the printing process. The specific method for determining the stop point is: Performance goals, determine to enhance a stop point within the interval distance of 5 to 10 mm; 2) In the printing code, determine the position of each interval point and its code; 3) Modify the code of the printing section, insert the code of the stop point, and modify it synchronously The amount of printing material used.

For example, there is the following code in the printing process:

...

G1 X63.132 Y11.081 E13.77165//Continue printing to (63.132, 11.081)E increment indicates the amount of printing material;

...

The content of "//" is the explanation part.

...

G4 P200//Stay at point P (49.458, 11.081) for 200MS

G1 X63.132 Y11.081 E13.77165//continue to print to (63.132, 11.081)

...

Use the modified printing code to complete the processing of 3D printing parts;

Again, preheat the 3D printed part to 130 degrees and put it into the injection mold with a temperature of 80 degrees. At this time, with a little force, the printed part can be placed in the mold and easily fixed;

Afterwards, the PP raw material is filled into the injection mold, and after cooling, the 3D printed part and the polymer raw material injected after injection form a uniform combined part, and its appearance is shown in Figure 7;

Finally, the resulting combined parts are subjected to warpage and post-processing of stress distribution, that is, the parts are placed in a fixture that is compatible with its shape, and kept at a temperature of 10 to 30 degrees below the melting point for 5 to 20 minutes Finally, products with excellent mechanical properties, or special conductivity properties, or special regulation effects can be obtained.

The prepared products were tested for tensile properties, and the test results are shown in Table 1.

From the results, it can be seen that the tensile strength of the product obtained after combining 3D printing and injection molding is as high as 39.8 MPa, and the Young's modulus is 2041 MPa. This result far exceeds the theoretical result (the tensile strength after conversion according to the two-phase law model should be 34.78MPa, and the Young's modulus should be 1449MPa), thus indicating the synergistic effect of the two parts of the material in the process and confirming the method. Effectiveness in improving mechanical properties.

In addition, after removing the 3D printing part in the composite part, only the PP material in the slender flow channel part was tested, and it was found that the tensile strength of the PP in this part was as high as 31.1MPa, compared with the pure PP tensile strength of 27.5MPA , the performance of the material is significantly improved, which may be related to the obvious drafting effect of the PP molecular chain when it flows in the printed part, which shows that the structure of the 3D printed part in this application is conducive to improving the performance of PP in the flow direction.

Its internal structure shows that the combination between the printing material and the post-injection material is very tight, which is another main reason for the improvement of its mechanical properties, as shown in Figure 9.

Example 2 PC/ABS-FDM-slender flow channel+PP

Firstly, carry out the structural design of the 3D printed part, and the design process is also shown in Figure 3. According to the characteristics of the standard tensile spline to be processed, the structure of the 3D printed part mainly includes three parts, the bottom part is fixed to the mold , its width is controlled at 10.1mm, the end reinforcement part, the width is 10mm, and the slender flow channel part, its cross-sectional part accounts for 45% of the entire cross-sectional volume of the injection part (including the bottom fixed part); the printed part is shown in Fig. 5, wherein the left part of the part is the self-reinforcing part, the lower part of the part is the placement part in the mold, and the upper right part of the part is the melt flow control part, that is, the slender runner part. The basic structure of the part is similar to that in Figure 4, but lacks micro-grooves, and the arms of the melt flow regulation part are relatively smooth.

Secondly, according to the designed model, the software automatically generates the 3D printing source code, and directly prints out the part according to the code, as shown in Figure 4.

Again, preheat the 3D printed part to 120 degrees and put it into the injection mold with a temperature of 90 degrees. At this time, with a little force, the printed part can be placed in the mold and easily fixed;

Afterwards, the PP raw material is filled into the injection mold, and after cooling, the 3D printed part and the polymer raw material injected after injection form a uniform combined part, and its appearance is also shown in Figure 7;

Finally, the resulting combined parts are subjected to warpage and post-processing of stress distribution, that is, the parts are placed in a fixture that adapts to its shape, and kept at a temperature of 10 to 30 degrees below the melting point for 5 to 20 minutes According to the different performance characteristics of the printed parts, products with excellent mechanical properties, or special conductivity properties, or special control effects can be obtained.

The tensile performance test was carried out on the prepared product, and the test results are also shown in Table 1.

From the results, it can be seen that the tensile strength of the product obtained after combining 3D printing and injection molding is as high as 38.5 MPa, and the Young's modulus is 1997 MPa. This result far exceeds the theoretical result (the tensile strength converted according to the two-phase law model should be 35.69MPa, and the Young's modulus should be 1493MPa), thus indicating the synergistic effect produced by the two parts of the material in the process, and confirming that the method is effective in Improve the effectiveness of mechanical properties.

In addition, after removing the 3D printing part of the composite part, only the PP material in the slender flow channel part was tested, and it was found that the tensile strength of PP in this part was as high as 30.9MPa, compared with 27.5MPa of pure PP , the performance of the material is significantly improved, which may be related to the obvious drafting effect of the PP molecular chain when it flows in the printed part, which shows that the structure of the 3D printed part in this application is conducive to improving the performance of PP in the flow direction.

In order to illustrate the effect of the present invention, the mechanical properties of corresponding injection products and conventional three-dimensional printing products are listed as a comparison, and the comparison results are also listed in Table 1.

Comparative example 1 PC/ABS-FDM-macro gully+PP

Comparative Example 1 is mainly compared with the code retention effect in Example 1. The main method is to stay the code in Example 1 and design some macroscopic grooves directly in the printed part, as shown in Figure 6, but the existence of these grooves will destroy the flow of the melt instead, thus showing the improvement in the performance of the part Insufficient on.

Comparative example 2 PC/ABS-FDM-grid+PP

Comparative Example 2 is mainly compared with Example 2. The 3D printed part is designed in a grid shape. This structure is easy to design and print. The appearance of the printed part is shown in Figure 7. After the same process as in Example 2 Finally, the tensile strength of the obtained product is only 29.1MPa, and the Young's modulus is 1489MPa.

Table 1 Comparison of tensile properties of several products

It can also be seen from the data in Table 1 that the mechanical properties of the product of the present invention are greatly improved, so this type of product has the characteristics of excellent performance and thus has excellent application prospects.

In addition, the profiles of the products of Example 1 and Comparative Example 1 are also listed in Figure 8. From Figure 8, it can be seen that the warping of the product obtained in Example 1 is eliminated, while the product of Comparative Example 1 has serious warping. In addition, the internal structures of the products of Example 1 and Comparative Example 2 are also listed in Figure 9 and Figure 10 respectively. From the comparison of the figures, it can be seen that the 3D printed parts obtained in Example 1 are closely bonded to the injected melt, while for Scale 2 shows that there is an obvious gap between the 3D printed part and the injected melt, indicating that the interface force between the two is poor. The above shows that the implementation effect of the present invention is obvious.

Example 3 Conductive ABS-FDM-micro-groove+PP

In this embodiment, commercially available conductive grade ABS is used as the raw material for 3D printing, and PP is used as the raw material for injection. Its implementation process is consistent with embodiment 1. The electrical conductivity of the finally obtained combined part in the thickness and width directions is greatly improved than that of PP, showing the performance of conductive ABS, and its mechanical properties also have effects similar to those of Example 1.

Example 4 PA-SLS-slender flow channel+PP

In this example, PA is used as the raw material for 3D printing, and PP is used as the raw material for injection. Among them, the tensile strength of PP is 27.5MPa, the Young's modulus is 1099MPa, the tensile strength of PA printed parts is 46.2MPa, and the Young's modulus is 1591 MPa. The 3D printing process used is powder laser sintering SLS. Its implementation process is consistent with embodiment 2.

The tensile performance test of the prepared product shows that the tensile strength of the product obtained after combining 3D printing and injection molding is as high as 40.2MPa, and the Young's modulus is 1489MPa, which obviously exceeds the mechanical properties of pure PP. It also exceeds the theoretical value calculated by the two-phase law model (the tensile strength converted by the two-phase law model should be 35.91MPa, and the tensile modulus should be 1320MPa).

In addition, after removing the 3D printing part in the composite part, only the PP material in the slender flow channel part was tested, and it was found that the tensile strength of PP in this part was as high as 30.8MPa, compared with 27.5MPa of pure PP , the performance of the material is significantly improved, which may be related to the obvious drafting effect of the PP molecular chain when it flows in the printed part, which shows that the structure of the 3D printed part in this application is conducive to improving the performance of PP in the flow direction.

Comparative example 3 PA-SLS-grid+PP

The raw materials used in this comparative example are the same as in Example 4, and the structural design of the 3D printed part is consistent with that of Comparative Example 2. After the same process as in Example 4, the tensile strength of the obtained product is only 36.2MPa, Young’s modulus The weight is 1336MPa, thus shows that embodiment 4 is more obvious to the promoting effect of mechanical property.

Claims

A manufacturing method based on 3D printing and injection molding, is characterized in that, comprises the following steps:

(1) Design the structure of the 3D printed parts and complete the processing of the 3D printed parts;

(2) Preheat the 3D printed part and put it into the corresponding position of the injection mold;

(3) Fill the thermoplastic polymer raw material into the injection mold, and shape it after cooling, and the 3D printed part and the polymer raw material injected after injection form a uniform combined part;

(4) After the warpage and stress distribution are performed on the obtained combined parts, it is obtained.
According to the manufacturing method based on 3D printing and injection molding according to claim 1, it is characterized in that in step (1), analyze according to the structure of the injection part to be processed, determine its characteristics and use targets, and then determine the 3D The embedding position, size and shape characteristics of the printed parts, and the structural design of the 3D printed parts.
The manufacturing method based on 3D printing and injection molding according to claim 2, wherein the structural design of the 3D printed part includes a self-structural reinforcement part, an in-mold placement part and a melt flow control part; wherein, the self-structural reinforcement Partially guarantee that the printed parts will not deform when they are subjected to a pressure of 0-50MPa in the injection mold cavity. The part placed in the mold is 0.5% to 2% larger than the size of the corresponding position in the mold cavity. flows adapt to each other.
The manufacturing method based on 3D printing and injection molding according to claim 1, characterized in that in step (2), the preheating temperature of the 3D printed part is between 5 and 20 degrees lower than its heat distortion temperature, and the preheating The difference between the temperature and the temperature of the injection mold is between 0 degrees and 80 degrees.
The manufacturing method based on 3D printing and injection molding according to claim 1, characterized in that in step (4), the post-processing includes placing the workpiece in a fixture that matches the shape of the workpiece, and Keep it in the melting point range of 10-20 degrees for 5-20 minutes.
The manufacturing method based on 3D printing and injection molding according to claim 3, characterized in that, the melt flow control part of the 3D printed part is provided with flow channels.
According to the manufacturing method based on 3D printing and injection molding according to claim 6, it is characterized in that the inner wall surface of the flow channel is provided with micro-grooves, and the processing method of the micro-grooves is: during the printing process, a printing stop at a random position is set. point, and its dwell time is between 1 and 1000ms.
The manufacturing method based on 3D printing and injection molding according to claim 1, characterized in that in step (1), the processing of 3D printed parts includes a 3D printing code modification method that can increase the printing stop point, specifically including The following steps:

(1) Determine the interval distance between the stop points;

(2) Determine the number of interval points according to each printing segment;

(3) determine the position of each interval point;

(4) Modify the code of the printing section and insert N codes of the stop points.
The manufacturing method based on 3D printing and injection molding according to claim 1, wherein the molding process of 3D printing is at least one of FDM, SLS, POLYJET, MJF, and SLA.
An application of the product obtained by the manufacturing method according to any one of claims 1 to 9 to high-performance or functional injection molded products.