(d) Outline 2 along −Pd . (e) View along Pd . (f) Intersection of complete visible edges of Outline 1 and 2.

(g) View along −Pd .

Fig. 3.  Illustration of outline, outer edges and outer edge loop.

 Visibility of facets.

Lemma 1. Let OLE1 be an outline entity of the corresponding edge E1. If the outline completely matches with the original edge, which means OLE1 ≡ E1, this edge is visible in the viewing direction, as shown in Fig. 6.

Proof.   In Fig. 6, supposing Edge 1 (E1) is completely visible  along

−Pd and it is an edge of Surface 1 (S1), it would lead to E1 ∈ S1. Its projection EP1 belongs to the outside loop of projection 1 (OLP1),

which is the projection of the molding into the projection plane, as shown in Fig. 6. EP1 is swept along the parting direction and intersects with the molding. The intersection of the original model and the extrusion of EP1 is called outline edge 1 (OLE1), which further belongs to Outline 1 (OL1). So the following are obtained:

EP1  ∈ OLP1,    OLE1  ∈ OL1, (1)

since E1  and EP1  form a reference plane called RP , and EP1  and OLE1

are on the same surface. They also form a reference plane called RP r , since RP and RP r are both parallel to the parting direction. Therefore, RP  =  RP r  and E1  ∈  RP . So E1  is the intersection  line of S1  and RP . OLE1  is the intersection of S1  and RP , OLE1    ∈  S1.   It

• A 3D solid model of molding.

• The parting directions Pd and −Pd.

• The 3D external dimensions of the main core and cavity blocks.

Output:

thus proves OLE1   ∈ RP r  = RP . OLE1  is also the intersection line  of

S1 and RP . The two nonparallel planes have only one intersection line, there is thus OLE1  ≡ E1.

Assume E1 is partially visible, the conclusion of OLE1 ∈ RP and E1 ∈ RP can still be made. Since OLE1 belongs to Sr, which is the first surface it met, therefore, OLE1   ∈  Sr  and Sr   /=  S1. So OLE1  and

• Main core, main cavity, side-cores and the internal pins   with

their corresponding withdrawal directions.

E1  are not the same, which means  OLE1 

/=  E1. This is in conflict

In this process, the largest bounding entities along the parting directions are determined. By classifying all the geometrical entities into different types, the contact surfaces of  the main core, cavity and the secondary molding tools are extracted for the generation of these molding tool components. The approach is based on the Lemma 1.

摘要：经由自动识别的底切特征在注射模具为内部销自动设计一套方法显影。所述的方法来自动地识别所述底切特征首次提出。对于给定的分割方向，所有的内和外底切特征被识别基于几何实体的拓扑关系。外边缘环，其表示沿给定分割方向上的最大横截面的边界，被提取和修补。成型的表面，然后根据它们的几何实体的分类鉴定。为了鉴定在模制内深底切，主芯的投影，生成内部销和沿分模方向和销抽出方向他们的边界框。一旦确定中的任意两个内部销和主芯投影包围盒是否有交叉区域，深内底切的位置。该完整的方法最终实现，并且通过案例研究和处理复杂模制部件的方法的效率验证由此示出。