CN105398056A - Self-adaptive hierarchical algorithm for 3D (three-dimensional) printing - Google Patents

Abstract

The invention discloses a self-adaptive hierarchical algorithm for 3D (three-dimensional) printing. The self-adaptive hierarchical algorithm comprises the following steps: (1) according to a triangle normal vector of a 3D model in a STL format, solving an included angle alpha 0 between the normal vector of each triangle and the horizontal plane; (2) solving the corresponding layer thickness t0 of each triangle; (3) taking the maximum value of t0 as a try-cut value, carrying out trial hierarchy on the 3D model in the STL format, and beginning from the bottom the model; (4) after completing the first trial hierarchy, determine a layer thickness value of a first layer; ( 5) after determining the layer thickness value of the first layer, on the basis of the first layer, carrying out secondary trial hierarchy with the try-cut value as a layer thickness; (6) repeating the fourth step to determine a layer thickness value of a second layer; and (7) frequently repeating the fifth and sixth steps until hierarchy of the entire 3D model in the STL format is completed. In the premise of ensuring the accuracy of a shaped product, the algorithm can shorten the shaping time and improve the shaping efficiency, guarantee the printing precision and improve the shaping efficiency.

Description

3 D-printing adaptive layered algorithm

Technical field

The invention belongs to 3 D-printing process control technology field, particularly relate to a kind of 3 D-printing adaptive layered algorithm.

Background technology

In Layered manufacturing or rapid shaping, the layering of model is a very important step.The thickness of layering not only with the surface accuracy of profiled member about the time also with shaping is relevant.According to larger thickness value, the molding time of product is short but precision can be very low; According to less thickness value, the formed precision of product is high but molding time can be very long, so just there is a kind of contradiction between molding time and formed precision.That is to reduce molding time on the one hand when rapid shaping, will surface accuracy be improved on the other hand, so just can reach doulbe-sides' victory.But at present the thickness layered approach such as employings mostly in PROCESS FOR TREATMENT software, refers to Fig. 1, this layered approach simply but the contradiction that can not solve between formed precision and shaping efficiency.

Summary of the invention

The present invention provides a kind of adaptive layered algorithm based on model surface curvature for solving in known technology the technical problem that exists, and this algorithm can under the prerequisite ensureing shaped article precision, shortening forming time, improves shaping efficiency.

The technical scheme that the present invention takes for the technical problem existed in solution known technology is: a kind of 3 D-printing adaptive layered algorithm, adopts following steps:

One) the angle α of each leg-of-mutton normal vector and horizontal plane is obtained according to the triangulation method vector of the threedimensional model of STL form ₀;

Two) thickness t corresponding to each triangle is obtained according to following formula ₀:

$t=\frac{C}{sin\mathrm{\α}}$

Wherein, C is the default precision of 3 D-printing blocking routine, and α is the angle of triangulation method vector and horizontal plane, and t is the thickness value that triangle is corresponding;

Three) t is got ₀maximum as trial cut value, examination layering is carried out, from the bottom of model to the threedimensional model of STL form;

Four) after completing first time examination layering, take out all triangles and all triangles crossing with trial cut value that comprise in first examination layering, as the triangle of corresponding first examination layering, obtain corresponding first examination each triangle of layering and the angle α of horizontal plane according to leg-of-mutton normal vector ₁, adopt step 2) in formulae discovery go out each leg-of-mutton thickness value t of corresponding first examination layering ₁, get t ₁minimum of a value as the thickness value of ground floor;

Five) after the thickness value of ground floor is determined, the basis of ground floor carries out second time with trial cut value for thickness and tries layering;

Six) step 4 is repeated) determine the thickness value of the second layer;

Seven) repeatedly step 5 is repeated) ~ six), until complete the layering of the threedimensional model of whole STL form.

The advantage that the present invention has and good effect are: with the curvature of model surface for classification foundation, the position large in curvature adopts less thickness value, and the position little in curvature adopts larger thickness value, under the prerequisite ensureing shaped article precision, can shortening forming time, improve shaping efficiency.The present invention can ensure printing precision, can improve shaping efficiency again.

Accompanying drawing explanation

Fig. 1 is the thickness layered effect figure such as existing;

Fig. 2 is existing STL form threedimensional model schematic diagram;

Fig. 3 is that STL form threedimensional model thickness calculates schematic diagram;

Fig. 4 is delaminating process schematic diagram of the present invention;

Fig. 5 is for adopting layered effect figure of the present invention.

Detailed description of the invention

For summary of the invention of the present invention, Characteristic can be understood further, hereby exemplify following examples, and coordinate accompanying drawing to be described in detail as follows:

Refer to Fig. 2, the threedimensional model of current 3 D-printing blocking routine process is STL form, and the threedimensional model of STL form, by tri patch in kind, namely adopts many triangle surfaces to form the curve external form of mock-up, therefore, the threedimensional model of STL form is similar to the one of material object.Each leg-of-mutton three point coordinates values and this leg-of-mutton normal vector is comprised in the stl file of threedimensional model.

Want to realize adaptive layered, first need calculate the curvature at each position of model.Then corresponding thickness value is adopted automatically according to the size of curvature.

Concrete grammar is:

One) refer to Fig. 3, obtain the angle α of each leg-of-mutton normal vector and horizontal plane according to the leg-of-mutton normal vector n of the threedimensional model of STL form ₀.

Two) thickness t corresponding to each triangle is obtained according to following formula ₀:

$t=\frac{C}{\sin \mathrm{\α}}$

Wherein, C is the default precision of 3 D-printing blocking routine, and α is the angle of triangulation method vector and horizontal plane, and t is the thickness value that triangle is corresponding.

Three) t is got ₀maximum as trial cut value, examination layering is carried out, from the bottom of model to the threedimensional model of STL form;

Four) after completing first time examination layering, take out all triangles and all triangles crossing with trial cut value that comprise in first examination layering, as the triangle of corresponding first examination layering, obtain corresponding first examination each triangle of layering and the angle α of horizontal plane according to leg-of-mutton normal vector ₁, adopt step 2) in formulae discovery go out each leg-of-mutton thickness value t of corresponding first examination layering ₁, get t ₁minimum of a value as the thickness value of ground floor, delaminating process refers to Fig. 4;

Five) after the thickness value of ground floor is determined, the basis of ground floor carries out second time with trial cut value for thickness and tries layering;

Six) step 4 is repeated) determine the thickness value of the second layer;

Seven) repeatedly step 5 is repeated) ~ six), until complete the layering of the threedimensional model of whole STL form.Design sketch after layering completes refers to Fig. 5.

In above-mentioned adaptive layered algorithm, with the size of the triangulation method at model a certain position vector with this place's curvature of size representative model of horizontal plane angle.According to the precision that process software is preset, calculate the thickness corresponding to each triangle in stl file, get maximum in all thickness values as trial cut value, trial cut model is carried out with this trial cut value, obtain all triangles of corresponding trial cut layer, comprise triangles all in trial cut thickness and the triangle crossing with trial cut value.Then find all leg-of-mutton normal vector of corresponding trial cut layer and calculate the angle of normal vector and horizontal plane, according to the formula calculating thickness, calculating the thickness value in this thickness corresponding to all triangles, get the thickness value of minimum of a value wherein as this layer.When cutting one deck, cutting on the basis of layer, still cutting into slices with trial cut value, calculating the thickness value of current layer according to the defining method cutting thick value layer by layer.Above-mentioned delaminating process is carried out in circulation, until threedimensional model is by complete layering.

Although be described the preferred embodiments of the present invention by reference to the accompanying drawings above; but the present invention is not limited to above-mentioned detailed description of the invention; above-mentioned detailed description of the invention is only schematic; be not restrictive; those of ordinary skill in the art is under enlightenment of the present invention; do not departing under the ambit that present inventive concept and claim protect, can also make a lot of form, these all belong within protection scope of the present invention.

Claims (1)

1. a 3 D-printing adaptive layered algorithm, is characterized in that, adopts following steps:

One) the angle α of each leg-of-mutton normal vector and horizontal plane is obtained according to the triangulation method vector of the threedimensional model of STL form ₀;

Two) thickness t corresponding to each triangle is obtained according to following formula ₀:

$t=\frac{C}{sin\mathrm{\α}}$

Wherein, C is the default precision of 3 D-printing blocking routine, and α is the angle of triangulation method vector and horizontal plane, and t is the thickness value that triangle is corresponding;

Three) t is got ₀maximum as trial cut value, examination layering is carried out, from the bottom of model to the threedimensional model of STL form;

Four) after completing first time examination layering, take out all triangles and all triangles crossing with trial cut value that comprise in first examination layering, as the triangle of corresponding first examination layering, obtain corresponding first examination each triangle of layering and the angle α of horizontal plane according to leg-of-mutton normal vector ₁, adopt step 2) in formulae discovery go out each leg-of-mutton thickness value t of corresponding first examination layering ₁, get t ₁minimum of a value as the thickness value of ground floor;

Five) after the thickness value of ground floor is determined, the basis of ground floor carries out second time with trial cut value for thickness and tries layering;

Six) step 4 is repeated) determine the thickness value of the second layer;

Seven) repeatedly step 5 is repeated) ~ six), until complete the layering of the threedimensional model of whole STL form.