TWI614121B - System and method for 3d printing - Google Patents

Abstract

The invention provides a three-dimensional printing method and a system thereof, wherein the method includes: establishing a mapping relationship between the support degree of upper-layer slices of each layer slice and a plurality of filling densities; slicing a three-dimensional printing object model to obtain multi-layer slices; obtaining each layer The extent to which the slice supports the upper slice, and the filling density of each slice is determined according to the mapping relationship; the determined slice density is used for stereoscopic printing of each slice. The invention provides a three-dimensional printing method that balances the strength of printing consumables and objects, and adds a judgment criterion. According to the support relationship between the slice of each layer and the upper and lower slices, a suitable filling density is selected, which does not waste printing materials, but also improves printing. Print quality, control printing time within a reasonable range, increase the probability of printing success, and reduce the cost of three-dimensional printing.

Description

Three-dimensional printing method and system

The present invention relates to the field of printing technology, and in particular, to a three-dimensional printing method and system for improving printing quality on the basis of saving materials.

Three-dimensional printing technology is a printing method that uses digital model files as a basis, uses sticky materials, and constructs objects by layer-by-layer printing. It can automatically and quickly materialize design ideas into a structure and Functional prototypes or direct manufacturing of parts can simplify the manufacturing process and produce a variety of goods quickly and efficiently. Therefore, in recent years, three-dimensional printing has developed rapidly.

In the layer-by-layer printing process, different filling densities of the materials will result in different printing effects. For example, when the filling density is low, you can speed up printing and save printing wires, but the probability of printing failure is high; when the filling density is high, you can increase the probability of printing success, but the printing time is long, and the printing material Expensive. In the conventional three-dimensional printing technology, the same filling density is generally used when printing objects. However, even for the same object, because the area and shape of each level are different from each other, uniformly using the same filling density will bring some problems.

For example, as shown in Figures 1 to 3, the schematic diagrams of the n-1th slice, the nth slice, and the n + 1th slice when the first example of the printing method in the conventional technique is used are shown in order. Parallel lines in the figure The space between the lines indicates the filling density. When the space between the lines that are parallel to each other is small, the lines are densely distributed, indicating that the filling density is large. When the space between the lines that are parallel to each other is large, the lines are loosely distributed, indicating the filling density small. There is a low-lying part at the center of the object, where the nth layer indicates that the figure appears at the center Shape-mutated slice. If the low-density filling method is used for layer-by-layer printing, there will be no support to rely on when printing on the low-lying part of the center, and the printing material will fall down directly, and the printed objects will be incomplete.

As another example, as shown in Figs. 4 to 6, the schematic diagrams of the n-1 layer slice, the n layer slice, and the n + 1 layer slice when the second example of the printing method in the conventional technology is used are sequentially shown. The distance between the parallel lines in the figure indicates the size of the filling density. There is a large change in the shape of the figure below the object, and here the n-th slice is a slice with a sudden change in the figure below. If the low-density filling method is used for layer-by-layer printing, there will be no support to rely on when printing the closed part that appears suddenly, and the printing wire will fall down directly, and the printed object will be broken. hole.

Aiming at the problems in the conventional technology, an object of the present invention is to provide a three-dimensional printing method and system, which can adjust the material filling density during the printing process according to the needs, so as not to waste the printing materials and improve the printing quality.

An embodiment of the present invention provides a three-dimensional printing method, including the following steps: establishing a mapping relationship between the support degree of upper-layer slices of each layer slice and multiple filling densities; slicing a three-dimensional printed object model to obtain multi-layer slices; and obtaining slice support of each layer The degree of the upper slice and the fill density of each slice are determined according to the mapping relationship; the three-dimensional printing is performed on each slice of the slice using the determined fill density; and the lower the degree of support of the slice to the upper slice, the fill density corresponding to the slice to be determined Bigger.

Preferably, the lower the degree of coincidence between the orthographic projection of the upper slice on the slice to be determined and the slice to be determined, the lower the degree of support of the slice to be determined on the upper slice.

Preferably, the mapping relationship is as follows: when it is determined that the slice cannot fully support the upper slice, the slice to be determined is an unsupported slice, unless the slice other than the supported slice is a supported slice, the supported slice uses the first filling density, and the unsupported slice is With the second packing density, the first packing density is smaller than the second packing density.

Preferably, before determining the filling density of slices of each layer, a step of determining mutation slices in the slices of each layer is further included. The judgment criterion of the mutation slices is: when the orthographic projection of the upper slice on the slice to be determined exists, the There is no internal support area, the upper slice is a mutation slice; determine the fill density of each slice, specifically: determine that at least one slice below each mutation slice is a non-support slice, except for slices other than the support slice, which are support slices. The first packing density, the non-supported slice uses the second packing density.

Preferably, the mapping relationship is specifically: when the outer wall of the slice to be determined and the upper slice cannot fully support the upper slice, the slice to be determined is an unsupported slice, unless the slice other than the supporting slice is a supporting slice, and the supporting slice is the first slice. A filling density, the non-supporting slice uses the second filling density, the first filling density is smaller than the second filling density; the outer contour line of the upper slice indents the inward deviation value to form the inner contour line, and the outer contour line and the inner contour line form The area is the outer wall of the upper slice.

Preferably, the deviation value is determined according to the nozzle diameter of the three-dimensional printing and the shape of the three-dimensional printing object model.

Preferably, before determining the filling density of each layer slice, the method further includes a step of determining mutation slices in each layer slice and a step of determining mutation slices that cannot be supported by the external wall, wherein the judgment criterion of the mutation slice is: when the upper slice is to be determined The orthographic projection on the slice has no internal support area that does not fall into the slice to be determined, and the upper slice is a mutation slice. Determining abrupt slices that cannot be supported by the outer wall, specifically including the following sub-steps: obtaining non-external wall support areas formed by the inner contour lines of the abrupt slices of each layer; Determine whether there is an overlapping area between the non-internal support area and the non-external wall support area. If so, the mutation slice cannot be supported by the external wall, otherwise the mutation slice can be supported by the external wall.

Preferably, determining the filling density of the slices of each layer is specifically: determining that at least one slice below the mutant slice that cannot be supported by the outer wall is a non-supporting slice, unless the other slices than the supporting slice are supporting slices, and the supporting slice adopts the first Packing density. Non-supported slices use a second packing density.

An embodiment of the present invention also provides a three-dimensional printing system to which the three-dimensional printing method is applied. The system includes: a mapping establishment unit for establishing a mapping relationship between the support degree of each slice on the upper slice and multiple filling densities; The three-dimensional printing object model is sliced to obtain multi-layered slices. The filling density determination unit is used to obtain the support degree of the upper slice from each slice and determine the fill density of each slice according to the mapping relationship. The printing unit is used to Stereo printing is performed on slices of each layer at the determined filling density.

The three-dimensional printing method and system provided by the present invention have the following advantages:

The invention provides a three-dimensional printing method that balances the strength of printing consumables and objects, and adds a judgment criterion. According to the support relationship between the slice of each layer and the upper and lower slices, a suitable filling density is selected, which does not waste printing materials, but also improves printing. Print quality, control printing time within a reasonable range, increase the probability of printing success, and reduce the cost of three-dimensional printing.

100‧‧‧Mapping unit

200‧‧‧ slice unit

300‧‧‧fill density determination unit

400‧‧‧printing unit

S100 to 400, S301-A to S303-A, S301-B to S304-B‧‧‧ steps

Other features, objects, and advantages of the present invention will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings.

FIG. 1 is a schematic diagram of n-1 slices when printing the first example using the printing method in the conventional technology.

FIG. 2 is a schematic diagram of n-layer slices when a first example is printed using a printing method in a conventional technique.

FIG. 3 is a schematic diagram of n + 1 slices when printing the first example using the printing method in the conventional technology.

FIG. 4 is a schematic diagram of the n-1 slice when the second example is printed using the printing method in the conventional technology.

FIG. 5 is a schematic diagram of n-layer slices when the second example is printed using the printing method in the conventional technology.

FIG. 6 is a schematic diagram of n + 1 slices when the second example is printed using the printing method in the conventional technology.

FIG. 7 is a flowchart of a three-dimensional printing method according to an embodiment of the present invention.

FIG. 8 is a flowchart of determining a filling density according to an embodiment of the present invention.

FIG. 9 is a flowchart of determining a filling density according to another embodiment of the present invention.

FIG. 10 is a schematic diagram of a contour when an internal support region is determined according to another embodiment of the present invention.

FIG. 11 is a schematic diagram of a contour when a support area without an external wall is determined according to another embodiment of the present invention.

FIG. 12 is a schematic diagram of a contour when a mutation slice that cannot be supported by an external wall is determined according to another embodiment of the present invention.

FIG. 13 is a schematic structural diagram of a three-dimensional printing system according to an embodiment of the present invention.

FIG. 14 is a schematic diagram of n-1 layer slices when the first example is printed using the printing method in the present invention.

FIG. 15 is a schematic diagram of n-layer slices when the first example is printed using the printing method in the present invention.

FIG. 16 is a schematic diagram of n + 1 layer slices when the first example is printed using the printing method in the present invention.

FIG. 17 is a schematic diagram of n-1 layer slices when a second example is printed using the printing method in the present invention.

FIG. 18 is a schematic diagram of n-layer slices when a second example is printed using the printing method in the present invention.

FIG. 19 is a schematic diagram of n + 1 slices when printing the second example using the printing method in the present invention.

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that the present invention will be comprehensive and complete, and the concept of the example embodiments will be fully conveyed to Those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and their repeated description will be omitted.

As shown in FIG. 7, it is a flowchart of a three-dimensional printing method according to an embodiment of the present invention, including the following steps: S100: Establish a mapping relationship between the support degree of upper-layer slices of each layer slice and various filling densities; S200: For stereo columns The printed object model is sliced to obtain multi-layered slices. S300: Obtain the extent that each slice supports the upper slice, and determine the fill density of each slice according to the mapping relationship. S400: Use the determined fill density to print the slices of each layer in three dimensions.

The present invention selects different packing densities in a printed object according to the degree of support of the upper slice by each slice, thereby avoiding the contradiction caused by using the same packing density in the entire printed object in the conventional technology.

In the following, two specific embodiments are used to further introduce the three-dimensional printing method of the present invention.

In one embodiment, the mapping relationship is preferably that the lower the support level of the slice to be determined for the upper slice, the greater the filling density corresponding to the slice to be determined. That is, when the slice to be determined cannot support the upper slice well, a larger packing density is used to increase the load-bearing capacity of the slice to be determined, thereby supporting the upper slice well.

When judging the degree of support of the slice to be determined for the upper slice, the following criteria can be used:

The lower the degree of coincidence between the orthographic projection of the upper slice on the slice to be determined and the slice to be determined, the lower the degree of support of the slice to be determined on the upper slice.

Because stereoscopically printed objects are printed layer by layer using stereo equipment, when the orthographic projection of the upper slice on the slice overlaps with the slice to be determined, the cut is to be determined at the overlapped location. The slice can give the upper slice a reliable support, and the orthographic projection of the upper slice on the to-be-determined slice has areas that do not coincide with the to-be-determined slice, and may not get good support. When the un-overlaid area is large, The filling density of the slice to be determined can be appropriately increased to enhance the supporting ability of the upper slice.

This embodiment divides a variety of filling densities into two types: a first filling density and a second filling density. The first filling density is smaller than the second filling density. The slices are divided into unsupported slices and supported slices according to the degree of support. For example, it refers to the slice that cannot rely on its shape to fully support the upper slice. Therefore, it is necessary to use a second filling density to enhance the supporting ability. For the support slice, it refers to the slice that can fully support the upper slice. Slice, so the support slice can meet the support requirements with the first filling density.

After slicing the three-dimensional printed object model, the requirements for determining the filling density are performed.

As shown in FIG. 8, it is a flowchart of determining a filling density according to an embodiment of the present invention. Determining the packing density includes the following sub-steps:

S301-A: determine the mutation slice in each slice; the mutation slice refers to the slice with a shape change compared with the lower slice. The specific mutation criterion is: when the orthographic projection of the upper slice on the slice to be determined exists The upper slice is a mutation slice that falls into the region without internal support within the slice to be determined. Because the shape of the mutation slice is abrupt relative to the lower slice, that is, the projection of the mutation slice on the lower slice does not completely coincide with the lower slice, so there is An area that cannot be supported by the shape of the lower slice itself, so the lower slice of a mutation slice has lower support than other slices.

S302-A: It is determined that at least one slice below each mutant slice is an unsupported slice, except that slices other than the support slice are supported slices; it is determined here that at least one slice below each mutant slice is an unsupported slice, because, in In practical applications, if only the fill density of a slice below the mutation slice is increased, it may still be insufficient to support the mutation slice well, and it may be necessary to further increase the packing density of the multilayer slice.

S303-A: Supported slices use the first packing density, and unsupported slices use the second packing density.

In practical applications, you can also set the fill density of all slices to a lower first fill density, and then, when determining the fill density, change the fill density of the unsupported slices to a higher second fill density; also The filling density of all the slices can be set to a higher second packing density, and then the filling density of the supporting slices can be changed to a lower first packing density when determining the packing density, which all belong to the protection scope of the present invention. Inside.

In another embodiment, the mapping relationship is preferably:

When the outer wall of the slice and the upper slice cannot be fully supported by the upper slice, the slice to be determined is an unsupported slice. Unless the slice other than the supporting slice is a supporting slice, the supporting slice adopts the first filling density, and the unsupported slice adopts the second. Packing density, the first packing density is smaller than the second packing density.

Therefore, compared with the previous embodiment, the present invention further increases the supporting capacity of the upper slice by considering the outer wall of the upper slice. Here the outer wall of the upper slice refers to: The inward deviation value of the contour line forms the inner contour line, and the area formed between the outer contour line and the inner contour line is the outer wall of the upper slice.

This embodiment divides a variety of filling densities into two types: a first filling density and a second filling density. The first filling density is smaller than the second filling density. The slices are divided into unsupported slices and supported slices according to the degree of support. For example, it refers to the slice that cannot rely on its shape to fully support the upper slice. Therefore, it is necessary to use a second filling density to enhance the supporting ability. For the support slice, it refers to the slice that can fully support the upper slice. Slice, so the support slice can meet the support requirements with the first filling density.

After slicing the three-dimensional printed object model, the requirements for determining the filling density are performed.

As shown in FIG. 9, it is a flowchart of determining a filling density according to another embodiment of the present invention.

S301-B: Determine the mutation slice in each slice; the method for determining the mutation slice here is the same as in the previous embodiment, that is, when there is no internal support area that does not fall into the slice to be determined when the orthographic projection of the upper slice on the slice to be determined exists The upper slice is a mutation slice; as shown in Figure 10, it shows a schematic diagram of the outline when the area without internal support is determined. Among them, A represents an orthographic projection contour figure of the mutation layer on the lower slice, and B represents the contour figure of the lower slice of the mutation layer. Subtract A-B from the two contour figures to get the part with filled pattern in the figure, that is, the area without internal support;

S302-B: Determine the abrupt slices that cannot be supported by the outer wall, including the following sub-steps: (1) Obtaining the outer wall-free support area formed by the inner contour lines of the abrupt slices of each layer; As shown in Figure 11, it is a contour diagram when the area without external support is determined. Among them, the part surrounded by the outer contour line of the abrupt layer is set to C, and a certain deviation value D is contracted inward to form the inner contour line. The deviation value is a value that the printing object cannot rely on the natural wall to rise upward, so the deviation value Determined according to the nozzle diameter of the three-dimensional printing and the shape of the three-dimensional printing object model; the area without external wall support is the part with the filling pattern in the figure, that is, the part surrounded by the inner contour line; (2) judging the area without internal support and Is there an overlapping area in the area without external wall support? If so, the mutation slice cannot be supported by the external wall, otherwise the mutation slice can be supported by the external wall.

As shown in Fig. 12, it is a contour diagram when determining a mutation slice that cannot be supported by an external wall. Where E is the area without internal support and F is the area without external wall support. Intersect the binary figure E and F to get the area G that is included in common, that is, the part with the filling pattern in the figure. If the area G is not a hole, then The mutation slice cannot be supported by the external wall, otherwise the mutation slice can be supported by the external wall.

S303-B: It is determined that at least one slice below the mutation slice that cannot be supported by the outer wall is a non-supporting slice, unless the slices other than the support slice are supporting slices; similarly, it is determined here that at least one slice below each mutation slice is Non-supported slices are because, in practical applications, if only the fill density of one slice below the mutant slice is increased, it may still be insufficient to support the mutant slice well, and the fill density of the multilayer slice may need to be further increased.

S304-B: Supported slices use the first packing density, unsupported slices use the second packing density.

Similarly, in practical applications, you can also set the fill density of all slices to a lower first fill density, and then when determining the fill density, change the fill density of the unsupported slices to a higher second fill. Density; you can also set the fill density of all slices to a higher second fill The filling density, and then when determining the filling density, changing the filling density of the supporting slices therein to a lower first filling density are all within the protection scope of the present invention.

As shown in FIG. 13, an embodiment of the present invention further provides a three-dimensional printing system to which the three-dimensional printing method is applied. The system includes: a mapping establishment unit 100 for establishing the support degree and various types of slices of each layer for the upper slice. Mapping relationship of the filling density; the slice unit 200 is used for slicing a three-dimensional printed object model to obtain a multi-layer slice; the filling density determination unit 300 is used to obtain the support degree of each slice of the upper slice and determine each layer according to the mapping relationship The filling density of the slices; the printing unit 400 is configured to perform stereoscopic printing on the slices of each layer by using the determined filling density.

As shown in Figs. 14 to 16, schematic diagrams of n-1 layer slices, n layer slices, and n + 1 layer slices when the first example is printed using the three-dimensional printing method of the present invention are shown. Similarly, the parallel lines in the figure The spacing between them indicates the size of the packing density. As in the first example of the prior art, there is a low-lying portion at the center of the object, and here the n-th layer represents a slice of a layer where a sudden change in graphics occurs at the center. Different from the prior art, the present invention increases the filling density in the n-1 layer, that is, the n-1 slice is printed with a higher filling density, so that the n layer slice is well supported. , To avoid the material from falling and becoming incomplete or broken.

As shown in Figures 17 to 19, it is a schematic diagram of n-1 layer slices, n layer slices, and n + 1 layer slices when the second example is printed using the three-dimensional printing method of the present invention. Similarly, the parallel lines in the figure The spacing between them indicates the size of the packing density. Same as the second example of the prior art, under the object There are large graphic shape changes at the square. The n-th slice is a slice with a sudden change in the graphics below. Different from the prior art, the present invention increases the filling density in the n-1 layer, that is, the n-1 slice is printed with a higher filling density, so that the n layer slice is well supported. , To avoid the material from falling and becoming incomplete or broken.

The three-dimensional printing method and the three-dimensional printing system provided by the present invention have the following advantages:

The invention provides a three-dimensional printing method that balances the strength of printing consumables and objects, and adds a judgment criterion. According to the support relationship between the slice of each layer and the upper and lower slices, a suitable filling density is selected, which does not waste printing materials, but also improves printing. Print quality, control printing time within a reasonable range, increase the probability of printing success, and reduce the cost of three-dimensional printing.

The above is a further detailed description of the present invention in combination with specific preferred embodiments, and it cannot be considered that the specific implementation of the present invention is limited to these descriptions. For those with ordinary knowledge in the technical field to which the present invention pertains, without deviating from the concept of the present invention, several simple deductions or replacements can be made, which should all be regarded as belonging to the protection scope of the present invention.

S100 to S400‧‧‧ steps

Claims (9)

A three-dimensional printing method includes the following steps: establishing a mapping relationship between the support degree of upper-layer slices of each layer slice and various filling densities; slicing a three-dimensional printing object model to obtain multi-layer slices; and obtaining the slices of each layer supporting the upper-layer slice. And the filling density of the slice of each layer is determined according to the mapping relationship; and the three-dimensional printing is performed on the slice of each layer by using the determined filling density; wherein the mapping relationship is specifically: the lower the degree of support of the slice to be determined for the upper layer slice, the The larger the fill density corresponding to the slice to be determined. The three-dimensional printing method according to item 1 of the scope of patent application, wherein the lower the degree of coincidence between the orthographic projection of the upper slice on the slice to be determined and the slice to be determined, the greater the degree of support of the slice to be determined on the upper slice. low. The three-dimensional printing method described in item 1 of the scope of patent application, wherein the mapping relationship is specifically: when the to-be-determined slice cannot fully support the upper slice, the to-be-determined slice is an unsupported slice, except for the unsupported slice. The other slices are support slices, the support slices use a first packing density, the non-support slices use a second packing density, and the first packing density is smaller than the second packing density. According to the three-dimensional printing method described in item 3 of the scope of patent application, before determining the filling density of the slice of each layer, the method further includes a step of determining a mutation slice in the slice of each layer. The judgment criterion of the mutation slice is: When the orthographic projection of the upper slice on the to-be-determined slice has no internal support area that does not fall into the to-be-determined slice, the upper-layer slice is a mutation slice; the determination of the filling density of the slice of each layer is specifically: determining each of the At least one layer below the mutant slice is an unsupported slice, and other slices except the unsupported slice are supported slices. The supported slice uses a first packing density, and the unsupported slice uses a second packing density. According to the three-dimensional printing method described in item 1 of the scope of patent application, wherein the mapping relationship is specifically: when neither the slice to be determined nor the outer wall of the upper slice can fully support the upper slice, the slice to be determined is an unsupported slice The other slices than the unsupported slice are supported slices, the supported slice uses a first packing density, the unsupported slice uses a second packing density, and the first packing density is smaller than the second packing density; and The inward deviation value of the outer contour line forms an inner contour line, and the area formed between the outer contour line and the inner contour line is the outer wall of the upper slice. The three-dimensional printing method described in item 5 of the scope of patent application, wherein the deviation value is determined according to the nozzle diameter of the three-dimensional printing and the shape of the three-dimensional printing object model. The three-dimensional printing method according to item 5 of the scope of patent application, wherein before determining the filling density of the slice of each layer, the method further includes a step of determining a mutation slice in the slice of each layer and a step of determining a mutation slice that cannot be supported by the outer wall, wherein : The judgment criterion of the mutation slice is: when there is an orthographic projection of the upper slice on the to-be-determined slice that has no internal support area that does not fall into the slice to be determined, the upper-layer slice is a mutation slice; the determination cannot be used by the external wall Supported mutation slices include the following sub-steps: Obtain non-exterior wall support areas formed by the inner contour of the abrupt slice of each layer; and determine whether there is an overlapping area between the non-internal support area and the non-external wall support area; if so, the abrupt slice cannot be supported by the outer wall, otherwise The mutant slice can be supported by the exterior wall. The three-dimensional printing method according to item 7 of the scope of patent application, wherein determining the filling density of the slice of each layer is specifically: determining at least one layer below the mutation slice that cannot be supported by the external wall, the slice is an unsupported slice, except that The slice other than the unsupported slice is a supported slice, the supported slice uses a first packing density, and the unsupported slice uses a second packing density. A three-dimensional printing system applied to the three-dimensional printing method described in any one of the claims 1 to 8 of the patent application scope. The three-dimensional printing system includes: a mapping establishment unit for establishing the support of each slice on the upper slice. Mapping relationship between degree and various filling densities; slice unit for slicing a three-dimensional printed object model to obtain multi-layer slices; fill density determining unit for obtaining the degree of support of the slice to the upper slice in each layer, and according to the mapping The relationship determines the filling density of the slice of each layer; and a printing unit for stereoscopically printing the slice of each layer with the determined filling density.