1, in the design of extrusion plastic bottles, if is made of high density polyethylene or polypropylene, plastic bottles of cross section should be rectangular or oval, low density polyethylene or other flexible material for plastic bottle, its round cross section as well. This allows content to be squeezed out of the plastic bottle. The plastic parts used in conjunction with plastic bottles are mainly bottle caps and seals. The design of plastic bottle mouth should be focused on; Consider how to make the plastic bottles better fit with the lid and the seal to fit the bottom of the plastic bottle, which is a weak part of the mechanical properties of the plastic bottle. Therefore, the bottom of the plastic bottle is generally designed as an inner concave shape; The corner of plastic bottle, and inside concave place, all do a big arc over. To facilitate the stacking of plastic bottles, increase the stacking stability of plastic bottles, and the bottom of plastic bottles should be designed with grooves.
2. When the surface of plastic bottle is labeled, the label should be flat. A "frame" can be designed on the surface of the plastic bottle so that the label can be accurately positioned and no movement is generated. In blow molding, the first contact of the billet blow up, always tends to harden the site. Therefore, the wall thickness of this part is also larger. At the edge and corner, it is the last contact part of billet blowing, which has a smaller wall thickness. Therefore, the edge of the plastic bottle and the area should be designed into rounded corners. Change the surface shape of the plastic bottle, such as the middle part of the plastic bottle, increase the surface of the plastic bottle to the groove or the convex ribs, which can improve the rigidity and bending resistance of plastic bottles. Longitudinal grooves or reinforcing bars can remove the drift, droop, or deformation of plastic bottles under long-term loads.
3. The printing surface of plastic bottles is the most concentrated part of consumers' attention. The printing surface shall be flat and continuous; If the plastic bottle contains handle, groove, reinforcement and so on, the design should be careful not to cause inconvenience to the printing operation. Elliptical plastic bottle, the rigidity is also high, but the mold manufacturing cost is higher. Therefore, in order to ensure the rigidity of plastic bottle, in addition to the materials with high stiffness, it is also necessary to design the plastic bottle to enhance the rigidity and strength of the plastic bottle.
4, since most plastic with notch sensitivity, plastic bottles at the sharp corners, mouth thread roots, in areas such as the neck, prone to fracture and cracking phenomenon, so these parts should be designed with rounded corners. For the transfer of rectangular plastic bottles, most of the load of the plastic bottle needs to be supported, so the wall thickness of the plastic bottle should be increased locally, and the stiffness and load resistance of the plastic bottle can be improved.