The contour design of glass packaging containers is divided into cross-sectional contour, longitudinal contour, neck-shoulder transition and bottle-root transition.
(1) Cross-sectional contour The cross-sectional contour of glass packaging containers can be designed as a circle, an ellipse, an E-face, a tetrahedron, a hexahedron, an oblate, a diamond and other shapes. The cross-sectional contour should be symmetrical, including axial symmetry or symmetry along two perpendicular axes. This can improve the mechanical properties of the bottle structure, facilitate the selection of the parting surface of the molding mold, and simplify the mold structure (Figure 2-51).
(2) Longitudinal section profile The longitudinal section profile should be combined with the characteristics of the cross-sectional profile to select variations and combinations. For example, if the cross-section is circular, the longitudinal profile of the vertical line is a straight cylindrical bottle shape; if the longitudinal profile is a combination of curves and curves, straight lines and curves, and straight lines and straight lines, it will form a variety of beautiful and structural rotating body bottles (Figure 2-52).
Glass containers with non-circular cross-sections, especially those with complex cross-sections, use a complex combination of curves in the longitudinal profile to form an intersecting structure with the non-circular cross-section. This will bring difficulties to mold design and manufacturing, and should be used less or not at all.
(3) Center of gravity of the container Glass packaging containers, especially bottles and cans, should strive to have a lower center of gravity. Bottle shapes with higher center of gravity have better stability when the center of gravity is located on the central axis of the bottle body.
(4) Bottle neck and shoulder design Bottle neck and shoulder are the connecting transition parts between the bottle mouth and the bottle body. They should be designed according to the shape and properties of the contents and combined with the shape, structural dimensions and strength requirements of the bottle body. For bottles and cans that are required to be recycled and reused, the principle of improving the strength indicators of the container should be followed to select and design the structure of the bottleneck and shoulder; for non-recyclable and reused glass bottles and cans, or those that are recycled and reused, or those that focus on aesthetics and emphasize meeting the spiritual needs of consumers, the design of the bottleneck and shoulder should comply with the requirements of the overall shape of the bottle and can, and the strength of the bottle body can meet general requirements.
The common structural forms of bottlenecks and shoulders are shown in Figure 2-53, including long neck, short neck, sloping shoulder, end shoulder, oblique shoulder, round shoulder, stepped shoulder and no shoulder. When designing, you can also combine and vary the common structural forms based on the needs of the overall shape.
(5) Design of bottle root As the connecting transition part between the bottle body and the bottle bottom, the shape of the bottle root is generally subject to the needs of the overall shape. However, the shape of the bottle root has a great influence on the strength index of the bottle, as shown in Figure 2-54. As shown in Figure 2-54 (a), the straight-walled bottle body adopts a small arc transition to connect with the bottle bottom. The vertical load strength of the structure is high, but the mechanical impact and thermal shock strength are relatively poor. Internal stress is often generated due to the different thicknesses of the bottle root and the bottle bottom. When subjected to mechanical impact or thermal shock, this place is very easy to break. As shown in Figure 2-54 (b), the bottle root uses a larger arc transition, and the lower part is connected to the bottle bottom in an inward form. The internal stress of the structure is small, the mechanical impact, thermal shock and water shock strength are high, and the vertical load strength is also good. As shown in Figure 2-54 (c), the bottle body and the bottle bottom are connected in a spherical transition structure. Its mechanical impact and thermal shock strength are good, but the vertical load strength and water shock strength are poor. Therefore, if it is not necessary for the shape, the bottle root structure shown in Figure 2-54 (c) should be avoided as much as possible from a structural point of view.
