WO2020143269A1

WO2020143269A1 - 4d printing method for double-layer structure based on temperature response

Info

Publication number: WO2020143269A1
Application number: PCT/CN2019/112668
Authority: WO
Inventors: 冯毅雄; 高一聪; 郑浩; 曾思远
Original assignee: 浙江大学
Priority date: 2019-01-07
Filing date: 2019-10-23
Publication date: 2020-07-16

Abstract

A 4D printing method for a double-layer structure based on a temperature response. The method comprises: selecting a shape memory polymer material, and by using a double-layer structure as a unit, repeatedly laminating and performing printing from bottom to top, wherein the double-layer structure is formed by laminating and printing two groups of different fill pattern layers in an up-down direction; each single layer of each group of fill pattern layers is printed to be an identical fill pattern; a pattern at an upper part is a horizontal stripe pattern; the horizontal stripe pattern is a texture pattern consisting of a group of linear arrays; the fill pattern layer at a lower part is one of a mesh pattern, a triangular stripe pattern, and a wiggle pattern. Therefore, one of a horizontal-mesh double-layer structure, a horizontal-triangular stripe double-layer structure, and a horizontal-wiggle double-layer structure is formed. The present invention overcomes the problems that it is currently difficult for preparing a temperature-driven 4D printing material and the degree of response to low-power deformation is small, and achieves a fused deposition 4D printing method by programming design parameters, without manufacturing a special wire.

Description

4D printing method of double-layer structure based on temperature response

Technical field

The invention relates to a 4D printing method in the field of 4D printing of smart materials, in particular to a double-layer structure 4D printing method based on temperature response, which realizes a fused deposition 4D printing method that can be programmed through design parameters without manufacturing special wires .

Background technique

4D printing, as a material processing technology developed based on intelligent perception materials, provides a new way of breaking through limitations for the preparation of traditional deformed materials. For bending deformation, due to the non-uniformity of the shrinkage of the workpiece volume in the thickness direction will cause the bending behavior of the multilayer material, 4D printing usually designs a multilayer structure with different responses to different structures. The conventional 4D printing deformation process generally consists of two implementation forms: 1. Two layers of the workpiece are composed of different materials, and through the same degree of excitation means (magnetic, thermal, biological response), through the two layers of different strain responses of the workpiece to achieve 4D Deformation effect. 2. Adopt a material to constitute the whole work piece, and achieve the effect of 4D printing deformation through different levels of stimulation.

Workpieces or equipment with advanced functions often need to combine complex three-dimensional shapes and functional induction structural units. Most technologies currently used to create functional structures can only work on a flat surface. In the past few years, due to the emergence of various advanced materials, the application range of shape memory materials has been extended. The shape memory polymer can achieve the shape memory effect through the transition between the low-temperature glass state and the high-temperature rubber state. At this time, the polymer has a self-healing property, and can be restored to the first squeeze to a certain extent by the temperature loading The state at the time of molding, based on the proposed various technologies, usually requires multiple manufacturing steps and special materials.

3D printing provides an active element spatial layout to achieve shape conversion technology, which is particularly represented by sophisticated multi-material printing, which can be used to combine different materials to achieve multi-shape or reversible deformation through polymers. Anisotropic additives (such as expansion ratio or stiffness) can be printed by 3D printing technology to achieve the deformation process of 4D printing. The initial planar structure is proposed, and after the corresponding trigger is obtained, their shape will change to a predetermined three-dimensional shape, thereby combining surface-related functions with complex three-dimensional shapes. At present, the 4D deformation under the system has many shortcomings. When the forming speed is fast, the processing equipment for the workpiece is extremely demanding, and complex workpiece planning is required. When the requirements for processing equipment are low, the forming speed is too slow. In real scenes, it is often necessary to overcome these two defect scenarios. Therefore, there is a need for a 4D printing method that can quickly deform while not requiring high processing equipment.

Summary of the invention

In view of the defects and improvement needs of the prior art, the present invention proposes a 4D printing method of a programmable double-layer shape memory structure based on temperature response, which includes the design and preparation of the double-layer shape memory structure.

The method of the present invention is a single-step printing process, requiring only a fused deposition 3D printer and polymer material, based on the self-folding and unstable ejection of the material, and the sequential deformation through programming, which can realize the three-dimensional expansion of the unprecedented space The shape is simple and versatile.

In order to realize the above process, the following technical solutions are adopted according to the present invention:

1. A 4D printing method of horizontal-triangular double-layer structure based on temperature response

1) Select the shape memory polymer material as the printed wire, and perform 3D printing according to the product model to be printed in the following manner: double-layer structure is repeatedly stacked from bottom to top for printing. The double-layer structure is mainly composed of two sets of different filling patterns The layer is stacked on top of each other, and the filling pattern layer includes multiple single layers. Each single layer in each group of filling pattern layers is printed with the same filling pattern. The single layer corresponds to a slice during 3D printing. The filling pattern above The layer is a horizontal grain pattern, and the lower filling pattern layer is a net pattern. The horizontal grain pattern is a texture pattern composed of a set of linear arrays. The net pattern is a texture pattern composed of two sets of linear arrays arranged crosswise. It consists of multiple parallel lines arranged at equal intervals;

2) After 3D printing, remove the coarse product obtained by printing, and perform precise temperature heating to deform the coarse product in a prescribed manner until the 4D deformation is completely completed, and wait for the workpiece to cool. The 4D printing process is completely completed to obtain the 4D printed product.

The product made by the 4D printing of the present invention is composed of a double-layer structure repeated from bottom to top. One layer is made by superimposing the same horizontal pattern multiple times, and the other layer is made by superimposing multiple layers of the net pattern. The thickness ratio of the textured layer can be adjusted from 1:4 to 4:1.

2. A 4D printing method based on the temperature response of the horizontal-triangular double-layer structure

1) Select the shape memory polymer material as the printed wire, and perform 3D printing according to the product model to be printed in the following manner: double-layer structure is repeatedly stacked from bottom to top for printing. The double-layer structure is mainly composed of two sets of different filling patterns The layer is stacked on top of each other, and the filling pattern layer includes multiple single layers. Each single layer in each group of filling pattern layers is printed with the same filling pattern. The single layer corresponds to a slice during 3D printing. The filling pattern above The layer is a horizontal grain pattern, and the lower filling pattern layer is a triangular grain pattern. The horizontal grain pattern is a texture pattern composed of a set of linear arrays, and the triangular grain pattern is a texture pattern composed of three sets of linear arrays arranged in a non-parallel cross arrangement. The linear array consists of multiple parallel lines arranged at equal intervals;

The product made by 4D printing of the present invention is composed of a double-layer structure repeated from bottom to top. One layer is made of the same horizontal grain pattern superimposed multiple times, and the other layer is made of multiple layers of triangular grain pattern. The thickness ratio of the triangle pattern layer can be adjusted from 1:4 to 4:1.

3. A 4D printing method based on temperature response of transverse-wiggle double-layer structure

1) Select the shape memory polymer material as the printed wire, and perform 3D printing according to the product model to be printed in the following manner: double-layer structure is repeatedly stacked from bottom to top for printing. The double-layer structure is mainly composed of two sets of different filling patterns The layer is stacked on top of each other, and the filling pattern layer includes multiple single layers. Each single layer in each group of filling pattern layers is printed with the same filling pattern. The single layer corresponds to a slice during 3D printing. The filling pattern above The layer is a horizontal grain pattern, and the fill pattern layer below is a wiggle pattern; the horizontal grain pattern is a texture pattern composed of a set of linear arrays, the linear array is composed of a plurality of parallel lines arranged at equal intervals, and the wiggle pattern is composed of a set of sinusoids The texture pattern formed by the array, the sine curve array is composed of a plurality of sine curves arranged in parallel with straight lines at equal intervals;

The product made by 4D printing of the present invention is composed of a double-layer structure repeated from bottom to top, where one layer is made by superimposing the same horizontal stripe pattern multiple times, and the other layer is made by stacking multiple layers of wiggle patterns. The horizontal stripe layer and wiggle The thickness ratio of the layer can be adjusted from 1:4 to 4:1.

Under the above three technical schemes, different double-layer structures and printing process parameter structures are selected according to the product model design to be printed during printing, and slice settings are made to obtain printed products of different shapes.

When printing, according to the design of the product model to be printed, different layouts in the filling pattern are constructed to adjust the different 4D deformation shapes of the final precise temperature heating. Different arrangement means that the printing angle of the linear array in the horizontal pattern is different; the intersection angle between the two sets of linear arrays in the net pattern and the printing angle of the two sets of linear arrays are different. The printing angle is essentially the linear direction and the printing coordinate system The angle between the horizontal axes; the intersection angle between each group of linear arrays in the triangular pattern and the printing angle of each group of linear arrays are different. The printing angle is essentially the angle between the linear direction and the horizontal axis of the printing coordinate system .

One embodiment is to set the printing angle of the linear array in the horizontal grain pattern within the range of 0±22.5 degrees or 90±22.5 degrees, so as to realize the curved deformation of the product after temperature heating around the rotation axis parallel to the horizontal axis of the printing coordinate system ; The degree of bending deformation of 0±22.5 degrees is smaller than that of 90±22.5 degrees. Only in the horizontal-wiggle double-layer structure technical solution, the closer the difference between the printing angle of the sinusoidal array in the wiggle pattern and the printing angle of the linear array in the horizontal pattern is to 90°, the greater the degree of bending.

Another embodiment is to set the printing angle of the linear array in the horizontal grain pattern within the range of 45±22.5 degrees or 135±22.5 degrees, so as to achieve spiral bending deformation of the product after temperature heating around the rotation axis perpendicular to the horizontal axis of the coordinate system. Only in the horizontal-wiggle double-layer structure technical solution, the closer the difference between the printing angle of the sinusoidal array in the wiggle pattern and the printing angle of the linear array in the horizontal pattern is to 90°, the greater the degree of distortion.

The 3D printing is performed by a fused deposition 3D printer, which needs to be cooled after printing.

When printing, according to the product model to be printed, different printing process parameters are built to match the different layout of the filling pattern to adjust the different 4D deformation degrees of the final precise temperature heating. The printing process parameters refer to the printing line width l, the printing layer height h and the printing nozzle temperature a during 3D printing, and the excitation temperature b during precise temperature heating, and the excitation temperature b is the heating temperature for precise temperature heating.

The 4D deformation degree is controlled by the four printing process parameters of printing line width l, printing layer height h, printing nozzle temperature a and excitation temperature b.

The setting range of the printing line width l is 0.25mm-0.8mm, the printing layer height h is 50μm-200μm, the nozzle temperature a during printing is 195°C-240°C, and the excitation temperature b is 65°C -95℃. In the end, the range of horizontal and longitudinal strains that can be achieved is 0.05-0.36.

The precise temperature heating is a heating method using a water bath, the solution component is distilled water, and the temperature of the aqueous solution is accurately controlled to stabilize the temperature of the heating process at the set excitation temperature b.

As the shape memory polymer material, a polylactic acid shape memory material with good stress-strain response performance when heated is used.

In the implementation of the method, the use of polymer wires for 3D printing is one of the main forms of fused deposition 3D printing. When the nozzle of the printer is extruded, the polymer material completes the initial deformation process. During the cooling process, the material undergoes the first stage of shape memory. When the molded workpiece is heated again, the printing wire will recover to a certain extent. The state at the time of drawing extrusion, the shape memory process is superimposed to realize the deformation process of 4D printing.

The invention edits each structural parameter and technological parameter of the model to design a model conforming to the expected deformation, and realizes the process of 4D printing by means of making a rough product model by 3D printer and accurately heating the material.

Compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1. The temperature-responsive programmable double-layer shape memory structure 4D printing structure of the present invention mainly uses the shape memory characteristics of polymer materials, which have the advantages of good processing performance, low cost and low requirements.

2. The present invention adopts the 4D printing method of fused deposition molding to print polymer materials. Compared with the hydrogel type material 4D printing method, the molding speed is fast, the processing requirements are low, and extremely special excitation conditions and manufacturing equipment are not required;

3. The present invention uses fused deposition molding 4D printing to print polymer materials. Compared with the 4D printing of the magnetoelectric process, the production cost is reduced, the material production process is simplified, the manufacturing cycle is shortened, and the structure and function are realized. Integrated manufacturing.

The invention overcomes the problems of current temperature-driven 4D printing material preparation difficulty and poor response to low-power deformation, realizes a fused deposition 4D printing method that does not need to manufacture special wires through programming of design parameters, and breaks through the tedious preparation of materials by 4D printing technology process.

BRIEF DESCRIPTION

FIG. 1 is a schematic diagram of the arrangement of horizontal stripes of the present invention;

2 is a schematic diagram of the layout of the net pattern of the present invention;

3 is a schematic view of the arrangement of the triangular pattern of the present invention;

4 is a schematic diagram of the layout of the wiggle pattern of the present invention;

FIG. 5 is a diagram of the strain effect of different printing temperatures when the transverse-web pattern of the polylactic acid material is combined;

FIG. 6 is a diagram of strain effects of different excitation temperatures during the combination of cross-grain of polylactic acid material;

7 is a diagram of the strain effect of different printed layer heights when the cross-grain combination of polylactic acid material is combined;

8 is a diagram of the strain effect of different printed line widths when the cross-texture of the polylactic acid material is combined;

9 is a graph of strain effects of different thickness ratios when the polylactide material is combined with cross-grain;

10 is a schematic view of the structure arrangement of two different filling patterns used in the workpiece in Example 1;

11 is a comparison diagram of the deformation process of the workpiece in Example 1 before and after;

12 is a schematic diagram of the structure arrangement of two different filling patterns used in the workpiece in Example 2;

13 is a comparison diagram before and after the deformation process of the workpiece in Example 2;

14 is a schematic diagram of the structural arrangement of two different filling patterns used in the workpiece in Example 3;

15 is a comparison diagram before and after the deformation process of the workpiece in Example 3;

16 is a diagram of the strain effect of different printing temperatures when the cross-triangle pattern of the polylactic acid material is combined;

17 is a diagram of strain effects of different excitation temperatures when the transverse-triangular pattern of the polylactic acid material is combined;

18 is a diagram of the strain effect of different printing layer heights when the transverse-triangular pattern of the polylactic acid material is combined;

FIG. 19 is a diagram of strain effects of different printed line widths when the transverse-triangular pattern of polylactic acid material is combined;

20 is a diagram of strain effects of different thickness ratios when the transverse-triangular pattern of the polylactic acid material is combined;

21 is a schematic diagram of the structural arrangement of two different filling patterns used in the workpiece in Example 4;

22 is a comparison diagram before and after the deformation process of the workpiece in Example 4;

23 is a schematic view of the structure arrangement of two different filling patterns used in the workpiece in Example 5;

24 is a comparison diagram before and after the deformation process of the workpiece in Example 5;

25 is a schematic diagram of the structure arrangement of two different filling patterns used in the workpiece in Example 6;

26 is a comparison diagram of the deformation process of the workpiece in Example 6 before and after;

FIG. 27 is a graph of the strain effect of different printing temperatures when the stripe-wiggle of polylactic acid material is combined;

Fig. 28 is a graph of strain effects at different excitation temperatures when the stripe-wiggle of polylactic acid material is combined;

Fig. 29 is a diagram of the strain effect of different printed layer heights when the polylactide material-wiggle is combined;

30 is a diagram of strain effects of different printed line widths when the polylactide material-wiggle is combined;

FIG. 31 is a graph of strain effects of different thickness ratios when the polylactide material is combined with transverse-wiggle;

32 is a schematic diagram of the structure arrangement of two different filling patterns used in the workpiece in Example 7;

33 is a comparison diagram before and after the deformation process of the workpiece in Example 7;

34 is a schematic diagram of the structure arrangement of two different filling patterns used in the workpiece in Example 8;

35 is a comparison diagram of the deformation process of the workpiece in Example 8 before and after;

36 is a schematic diagram of the structure arrangement of two different filling patterns used in the workpiece in Example 9;

37 is a comparison diagram before and after the deformation process of the workpiece in Example 9. FIG.

detailed description

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 accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as there is no conflict with each other.

The specific implementation process of the present invention is:

1) Select the shape memory polymer material as the printed wire, and perform 3D printing according to the product model to be printed in the following manner: double-layer structure is repeatedly stacked from bottom to top for printing. The double-layer structure is mainly composed of two sets of different filling patterns The layers are stacked on top of each other to form a printing arrangement. The filled pattern layer includes multiple single layers. Each single layer in each group of filled pattern layers is printed with the same filled pattern. The single layer corresponds to a slice of 3D printing.

As shown in Fig. 1, the horizontal grain pattern is a texture pattern composed of a set of linear arrays, and the linear array is composed of a plurality of parallel arranged straight lines.

As shown in FIG. 2, the mesh pattern is a texture pattern composed of two linear arrays arranged in a cross arrangement, and the linear array is composed of a plurality of parallel arranged linear lines.

As shown in FIG. 3, the triangular pattern is a texture pattern composed of three sets of linear arrays that are arranged in a non-parallel cross pattern. The corresponding straight lines in the three sets of linear arrays in the pattern intersect at the same point to form a tight array of regular triangles. The linear array consists of multiple parallel lines.

As shown in FIG. 4, the wiggle pattern is a texture pattern formed by a group of sinusoidal arrays. The sinusoidal array is composed of a plurality of sinusoids arranged in parallel with straight lines at equal intervals, and the reference axis where the sinusoids are located is parallel.

The number of single layers in the upper pattern layer and the number of single layers in the lower pattern layer may be the same or different.

2) After 3D printing, remove the crude product obtained by printing, and perform precise temperature heating to deform the crude product according to the prescribed method. Specifically, the water bath heating method is used. The solution component is distilled water, so that the temperature of the heating process is stable at the set accurate Excitation temperature b. After the deformation, a 4D printed product is obtained.

Specifically, the printing angle θ of the linear array in the horizontal pattern is adjusted at 0-180°, and the cross angle between the two linear arrays of the mesh pattern is selected to be 60°, 90°, and 120°, and the two linear arrays of the mesh pattern The printing angle θ is adjusted between 0-180°.

Specifically, the cross angle between each two sets of linear arrays of the angular pattern is adjusted at 0-90°, and the printing angle θ of the two sets of linear arrays of the triangular pattern is adjusted at 0-180°.

Specifically, the printing angle θ of the reference axis of the wiggle pattern sine curve array can be adjusted from 0 to 180°, and the printing angle is essentially the angle between the reference axis direction where the sine curve is located and the horizontal axis of the printing coordinate system.

Set the printing angle of the linear array in the horizontal pattern within the range of 0±22.5 degrees or 90±22.5 degrees, which can achieve the bending deformation of the product after temperature heating around the rotation axis parallel to the horizontal axis of the printing coordinate system; 0±22.5 degrees The degree of bending deformation is smaller than 90±22.5 degrees. The printing angle of the linear array in the horizontal pattern is set within the range of 45±22.5 degrees or 135±22.5 degrees, so that the heated product can be spirally deformed around the rotation axis perpendicular to the horizontal axis of the coordinate system. For horizontal-wiggle, the closer the difference between the printing angle of the sinusoidal array in the wiggle pattern and the printing angle of the linear array in the horizontal pattern is to 90°, the greater the degree of bending and twisting.

4D deformation degree is controlled by four printing process parameters: printing line width l, printing layer height h, printing nozzle temperature a and excitation temperature b. The larger the printing line width l, the greater the deformation degree, and the greater the printing layer height h, the more deformation degree Smaller, the higher the printing nozzle temperature a, the smaller the degree of deformation, and the higher the excitation temperature b, the greater the degree of deformation.

The setting range of printing line width l is 0.25mm-0.8mm, the height h of the printing layer is 50μm-200μm, the nozzle temperature a during printing is 195℃-240℃, and the excitation temperature b is 65℃-95℃ . In a specific implementation, the printable line width l can be set in the range of 0.25mm-0.8mm.

In the cross-mesh double-layer structure and the cross-triangle double-layer structure, the range that can finally achieve the horizontal and longitudinal strains is 0.05-0.36. In the transverse-wiggle double-layer structure, the transverse and longitudinal strains can reach a range of 0.05-0.41.

Before the product is printed, according to the result of the double layer, the filling pattern of each single layer is different. For the filling pattern of each single layer, the printing line width l, the printing layer height h, the printing nozzle temperature a, and the precise temperature heating during 3D printing The excitation temperature b is set and pre-programmed, so that the final product strain quickly reaches the desired effect.

During the specific implementation, each printing process parameter is tested by a single factor to obtain the 4D heating deformation result corresponding to each printing process parameter.

1. In the case of horizontal-net double-layer structure, the test of different printing process parameters:

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing temperature is adjusted and changed to obtain the deformation degree corresponding to different printing temperatures, as shown in Figure 5, the points on the solid line can be seen in the figure Is the maximum value of the strain (ordinate) that can be reached at the printing temperature (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) that can be reached at the printing temperature (abscissa), and the correspondence between the two lines is Printable temperature strain range.

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the excitation temperature is adjusted and changed to obtain the deformation degree corresponding to different excitation temperatures, as shown in Figure 6, the points on the solid line can be seen in the figure Is the maximum value of the strain (ordinate) at the excitation temperature (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) at the excitation temperature (abscissa), the correspondence between the two lines is Strain range achievable by excitation temperature.

In the case where the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing layer height is adjusted and changed to obtain the corresponding deformation degree of different printing layer height, as shown in Figure 7, the solid line can be seen in the figure The point is the maximum value of the strain (ordinate) at the height of the printed layer (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) at the height of the print layer (abscissa), two lines Between is the strain range that can be achieved corresponding to the height of the printed layer.

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing line width is adjusted and changed to obtain the corresponding deformation degree of different printing line width, as shown in Figure 8, the solid line can be seen in the figure The point is the maximum value of the strain (ordinate) under the printed line width (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) under the print line width (abscissa), two lines Between is the strain range that can be achieved by the corresponding printed line width.

In the case where the other four printing process parameters remain unchanged and the same two-layer structure is 3D printed, the thickness ratio of the two-layer structure is adjusted and changed to obtain the deformation degree corresponding to the different thickness ratio, as shown in FIG. 9 The point on the line is the average value of the strain (ordinate) that can be achieved under the thickness ratio (abscissa), and the point on the dotted line is the minimum value of the strain (ordinate) that can be achieved under the thickness ratio (abscissa). Between is the strain range achievable for the corresponding thickness ratio.

2. In the case of horizontal-triangular double-layer structure, the test of different printing process parameters:

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing temperature is adjusted and changed to obtain the deformation degree corresponding to different printing temperatures, as shown in Figure 16, the dots on the solid line can be seen in the figure Is the maximum value of the strain (ordinate) that can be reached at the printing temperature (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) that can be reached at the printing temperature (abscissa), and the correspondence between the two lines is Printable temperature strain range.

In the case where the other four printing process parameters remain unchanged and the same two-layer structure is 3D printed, the excitation temperature is adjusted and changed to obtain the deformation degree corresponding to the different excitation temperature, as shown in Figure 17, the points on the solid line can be seen in the figure Is the maximum value of the strain (ordinate) at the excitation temperature (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) at the excitation temperature (abscissa), the correspondence between the two lines is Strain range achievable by excitation temperature.

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing layer height is adjusted and changed to obtain the corresponding deformation degree of different printing layer height, as shown in Figure 18, the solid line can be seen in the figure The point is the maximum value of the strain (ordinate) at the height of the printed layer (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) at the height of the print layer (abscissa), two lines Between is the strain range that can be achieved corresponding to the height of the printed layer.

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing line width is adjusted and changed to obtain the corresponding deformation degree of different printing line width, as shown in Figure 19, the solid line can be seen in the figure The point is the maximum value of the strain (ordinate) under the printed line width (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) under the print line width (abscissa), two lines Between is the strain range that can be achieved by the corresponding printed line width.

In the case where the other four printing process parameters remain unchanged and the same two-layer structure is 3D printed, the thickness ratio of the two-layer structure is adjusted and changed to obtain the deformation degree corresponding to the different thickness ratio, as shown in FIG. 20. The point on the line is the maximum value of the strain (ordinate) under the thickness ratio (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) under the thickness ratio (abscissa), the two lines Between is the strain range achievable for the corresponding thickness ratio.

3. In the case of horizontal-wiggle double-layer structure, the test of different printing process parameters:

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing temperature is adjusted to obtain the deformation degree corresponding to different printing temperatures, as shown in Figure 27, the dots on the solid line can be seen in the figure Is the maximum value of the strain (ordinate) that can be reached at the printing temperature (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) that can be reached at the printing temperature (abscissa), and the correspondence between the two lines is Printable temperature strain range.

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the excitation temperature is adjusted and changed to obtain the deformation degree corresponding to different excitation temperatures, as shown in FIG. 28, the points on the solid line can be seen in the figure Is the maximum value of the strain (ordinate) at the excitation temperature (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) at the excitation temperature (abscissa), the correspondence between the two lines is Strain range achievable by excitation temperature.

In the case that the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing layer height is adjusted and changed to obtain the corresponding deformation degree of different printing layer height, as shown in Figure 29, the solid line can be seen in the figure The point is the maximum value of the strain (ordinate) at the height of the printed layer (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) at the height of the print layer (abscissa), two lines Between is the strain range that can be achieved corresponding to the height of the printed layer.

In the case where the other four printing process parameters remain unchanged and the same two-layer structure 3D printing, the printing line width is adjusted and changed to obtain the corresponding deformation degree of different printing line width, as shown in Figure 30, the solid line can be seen in the figure The point is the maximum value of the strain (ordinate) under the printed line width (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) under the print line width (abscissa), two lines Between is the strain range that can be achieved by the corresponding printed line width.

In the case where the other four printing process parameters remain unchanged and the same two-layer structure is 3D printed, the thickness ratio of the two-layer structure is adjusted and changed to obtain the deformation degree corresponding to the different thickness ratio, as shown in Figure 31. The point on the line is the maximum value of the strain (ordinate) under the thickness ratio (abscissa), the point on the dotted line is the minimum value of the strain (ordinate) under the thickness ratio (abscissa), the two lines Between is the strain range achievable for the corresponding thickness ratio.

The specific embodiments of the present invention are as follows:

Cross-mesh double-layer structure

Example 1

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is established by using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ³ , and the deformation of the workpiece is intended to have a lateral strain of 0.36 and a longitudinal strain of 0.07.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single-layer horizontal grain patterns with a printing angle of 90°, and the lower layer uses 150 single-layer grid patterns with a crossing angle of 90° and printing angles of 45° and 135°, respectively, as shown in FIG. 10 It shows that the thickness ratio of the two layers is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(3) At this time, the printing temperature is selected to be 195°C, and output to the fused deposition 3D printing processing center through the slicing software to perform the 3D printing process and wait for the workpiece to cool;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely finished. Figure 11 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 11 is before excitation, and the right picture of Figure 11 is after excitation. The rotation axis of the horizontal axis of the coordinate system is curved and deformed, and the two ends are folded up and bent. The whole preparation process takes only 24 minutes, which greatly reduces the production time of the product compared with traditional printing.

Example 2

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is created using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ^3. The deformation of the workpiece is intended to have a lateral strain of 0.15 and a longitudinal strain of 0.12.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 monolayers with a horizontal grain pattern with a printing angle of 45°, and the lower layer uses a mesh pattern with 150 monolayers with a cross angle of 90° and printing angles of 45° and 135°, as shown in Figure 12 It shows that the thickness ratio of the two layers is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 13 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 13 is before excitation, and the right picture of Figure 13 is after heating. The rotating axis of the shaft is spirally bent and deformed, and the entire preparation process takes only 24 minutes, which greatly shortens the product manufacturing time.

Example 3

(1) First of all, the three-dimensional model of a two-layer workpiece using polymer for 4D printing is established using three-dimensional modeling software. The size of the product workpiece is 10*40*1.5mm ^3. The deformation of the workpiece is intended to have a lateral strain of -0.20 and a longitudinal strain of- 0.12.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single layers of a horizontal grain pattern with a printing angle of 0°, and the lower layer uses a mesh pattern of 150 single layers with a cross angle of 90° and a printing angle of 45° and 135°, as shown in Figure 14, The thickness ratio of the two layers is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 15 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 15 is before excitation, and the right picture of Figure 15 is after excitation. The rotation axis of the shaft is curved and deformed, and the two ends are bent downwards, but the bending direction is opposite to that in Example 1. The entire preparation process takes only 24 minutes, which greatly shortens the product manufacturing time.

Horizontal-triangular double-layer structure

Example 4

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is created by using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ³ , and the deformation of the workpiece is intended to have a lateral strain of 0.32 and a longitudinal strain of 0.12.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single layers of horizontal stripes with a printing angle of 90°, and the lower layer uses 150 single layers of 3 cross angles of 60° and printing angles of 0°, 60° and 120° respectively. The pattern, as shown in Figure 21, the thickness ratio of the two layers is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 22 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 22 is before excitation, and the right picture of Figure 22 is after excitation. The rotation axis of the horizontal axis of the coordinate system is curved and deformed, and both ends are folded up and bent. The whole preparation process takes only 24 minutes, which greatly shortens the production time compared with traditional printing.

Example 5

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is established by using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ³ , and the deformation of the workpiece is intended to have a lateral strain of 0.22 and a longitudinal strain of 0.20.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single layers of horizontal stripes with a printing angle of 45°, and the lower layer uses 150 single layers of 3 cross angles of 60°, and the printing angles are 0°, 60° and 120° of the triangular pattern. The pattern, as shown in Figure 23, the thickness ratio of the two layers is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 24 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 24 is before excitation, and the right picture of Figure 24 is after heating. The rotating axis of the shaft is spirally bent and deformed, and the entire preparation process takes only 24 minutes, which greatly shortens the production time of the process.

Example 6

(1) First of all, the three-dimensional model of a two-layer workpiece using polymer for 4D printing is established using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ^3. The deformation of the workpiece is intended to have a lateral strain of -0.21 and a longitudinal strain of- 0.11.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single layers of horizontal stripes with a printing angle of 0°, and the lower layer uses 150 single layers of 3 cross angles of 60° and printing angles of 0°, 60° and 120° respectively. The pattern, as shown in Figure 25, the thickness ratio of the two layers is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 26 is a comparison of the workpiece before and after heating and excitation in this 4D process. The left picture of Figure 26 is before excitation, and the right picture of Figure 26 is after excitation. The rotation axis of the shaft is curved and deformed, and the two ends are bent downwards, but the bending direction is opposite to that of Example 4. The entire preparation process takes only 24 minutes, which greatly shortens the process manufacturing time.

Horizontal-wiggle double-layer structure

Example 7

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is established by using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ^3. The deformation of the workpiece is intended to have a lateral strain of 0.41 and a longitudinal strain of 0.10.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single-layer printed patterns with a 0° horizontal grain pattern, and the lower layer uses 150 single-layer printed angles of 90°, a wiggle pattern formed by a sinusoidal array, as shown in Figure 32, two layers The thickness ratio is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 33 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 33 is before excitation, and the right picture of Figure 33 is after excitation. The rotation axis of the horizontal axis of the coordinate system is curved and deformed, and the two ends are folded up and bent. The whole preparation process takes only 24 minutes, which greatly reduces the production time of the product compared with traditional printing.

Example 8

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is established using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ^3. The deformation of the workpiece is intended to have a lateral strain of 0.15 and a longitudinal strain of 0.14.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single-layer printed patterns with a 45° horizontal grain pattern, and the lower layer uses 150 single-layer printed patterns with a sinusoidal array with a printed angle of -45°. As shown in Figure 34, the two-layered The thickness ratio is 1:1, the layered slice processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 35 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 35 is before excitation, and the right picture of Figure 35 is after heating. The rotating axis of the shaft is spirally bent and deformed, and the entire preparation process takes only 24 minutes, which greatly shortens the production time of the product.

Example 9

(1) Firstly, a three-dimensional model of a two-layer workpiece using polymer for 4D printing is established by using three-dimensional modeling software. The product workpiece size is 10*40*1.5mm ^3. The deformation of the workpiece is intended to have a lateral strain of -0.14 and a longitudinal strain of- 0.04.

(2) Select polylactic acid as the shape memory material for 3D printing, use the slicing software to slice the three-dimensional model layer by layer, and set the printing layer height and printing line width according to the desired deformation. The selected line width is 0.4mm, the selected layer height is 50μm. The upper layer of the workpiece uses 150 single-layer printed patterns with a 90° horizontal grain pattern, and the lower layer uses 150 single-layer printed angles of 0° in a wiggle pattern formed by a sinusoidal array, as shown in Figure 36, layered and sliced The processing results and the identified parts are input into the computer control system;

(4) The cooled workpiece is heated at a precise temperature, and the selected excitation temperature is 85°C until the required 4D deformation is completely completed. Wait for the workpiece to cool again. The 4D printing process is completely completed. Figure 37 is a comparison of the workpiece before and after heating and excitation in the 4D process. The left picture of Figure 37 is before excitation, and the right picture of Figure 37 is after excitation. The rotation axis of the shaft is curved and deformed, and both ends are bent downwards, but the bending direction is opposite to that of Example 7. The entire preparation process takes only 24 minutes, which greatly shortens the production time of the product.

Claims

A 4D printing method for a double-layer structure based on temperature response is characterized by the following steps:

1) Select shape memory polymer material as the printed wire, and perform 3D printing according to the product model to be printed in the following manner: double-layer structure is repeatedly laminated from bottom to top for printing, and the double-layer structure is composed of two sets of different filling pattern layers It is composed of a layered printing arrangement on top and bottom. The filled pattern layer includes multiple single layers. Each single layer in each group of filled pattern layers is printed with the same filled pattern. The single layer corresponds to a slice in 3D printing. The filled pattern layer above It is a horizontal grain pattern. The horizontal grain pattern is a texture pattern composed of a set of linear arrays. The linear array is composed of a plurality of parallel lines arranged at equal intervals. The fill pattern layer below is the mesh pattern, triangle pattern, wiggle pattern. One, to form one of the horizontal-net, horizontal-triangular, horizontal-wiggle double-layer structure;

2) After 3D printing, remove the coarse product obtained by printing, and perform precise temperature heating to deform the coarse product in a prescribed manner until the 4D deformation is completely completed to obtain a 4D printed product.
The 4D printing method of double-layer structure based on temperature response according to claim 1, characterized in that: the horizontal-mesh double-layer structure: the filling pattern layer below is a net pattern, and the net pattern is composed of two Texture pattern composed of a cross array of linear arrays.
The 4D printing method of double-layer structure based on temperature response according to claim 1, wherein: the horizontal-triangular double-layer structure: the filling pattern layer below is a triangular pattern, and the triangular pattern is composed of three Group of linear arrays are non-parallel texture patterns formed by cross arrangement.
The 4D printing method of double-layer structure based on temperature response according to claim 1, characterized in that: the horizontal-wiggle double-layer structure: the filling pattern layer below is a wiggle pattern, and the wiggle pattern is composed of a set of sinusoids The texture pattern formed by the curved array, the sinusoidal array consists of a plurality of sinusoids arranged in parallel with straight lines at equal intervals.
A 4D printing method for a double-layer structure based on temperature response according to claim 1, characterized in that different layouts in the filling pattern are designed and constructed according to the product model to be printed when printing to adjust different 4D deformations of the final precise temperature heating shape.
A 4D printing method for a double-layer structure based on temperature response according to claim 5, wherein in the horizontal-mesh double-layer structure, the printing angle of the linear array in the horizontal grain pattern is set at 0±22.5 degrees Or within the range of 90±22.5 degrees, the product after temperature heating is bent and deformed around the rotation axis parallel to the horizontal axis of the printing coordinate system; the printing angle of the linear array in the horizontal pattern is set at 45±22.5 degrees or 135±22.5 degrees Within the scope, the temperature-heated product is spirally deformed around a rotation axis perpendicular to the horizontal axis of the coordinate system.
A 4D printing method for a double-layer structure based on temperature response according to claim 5, wherein in the horizontal-triangular double-layer structure, the printing angle of the linear array in the horizontal grain pattern is set at 0±22.5 degrees Or within the range of 90±22.5 degrees, the product after temperature heating is bent and deformed around the rotation axis parallel to the horizontal axis of the printing coordinate system; the printing angle of the linear array in the horizontal pattern is set at 45±22.5 degrees or 135±22.5 degrees Within the scope, the temperature-heated product is spirally deformed around the rotation axis perpendicular to the horizontal axis of the coordinate system;
A 4D printing method for a double-layer structure based on temperature response according to claim 5, characterized in that: in the horizontal-wiggle double-layer structure, the printing angle of the linear array in the horizontal pattern is set at 0±22.5 degrees Or within the range of 90±22.5 degrees, the product after temperature heating is bent and deformed around the rotation axis parallel to the horizontal axis of the printing coordinate system; the printing angle of the linear array in the horizontal pattern is set at 45±22.5 degrees or 135±22.5 degrees Within the scope, the temperature-heated product is spirally deformed around a rotation axis perpendicular to the horizontal axis of the coordinate system.
The 4D printing method of double-layer structure based on temperature response according to claim 1, characterized in that: when printing, different printing process parameters are designed and constructed according to the product model to be printed, and different arrangements of the filling patterns are adjusted to adjust the final precise temperature Different degrees of 4D deformation during heating.
A 4D printing method for a double-layer structure based on temperature response according to claim 9, characterized in that the degree of 4D deformation consists of the printing line width l, the printing layer height h and the printing nozzle temperature a and the excitation temperature b Four printing process parameter control.
A 4D printing method for a double-layer structure based on temperature response according to claim 10, characterized in that: the setting range of the printing line width l is 0.25mm-0.8mm, and the printing layer height h is 50μm- 200 μm, the nozzle temperature a during printing is 195°C-240°C, and the excitation temperature b is 65°C-95°C.
A 4D printing method of double-layer structure based on temperature response according to claim 1, characterized in that: the precise temperature heating is a method of using a water bath to accurately control the temperature of the aqueous solution, so that the temperature of the heating process Stable at the set excitation temperature b.
The 4D printing method for a double-layer structure based on temperature response according to claim 1, wherein the shape memory polymer material uses polylactic acid shape memory material.