Teacher Xiaosha from Dongguan: Sharing the basic design of PROE product design, plastic product structure
The design of plastic products involves a wide range of aspects. In practice, various shapes and structural forms will be encountered. The knowledge involved includes: material selection, mold structure and product relationship, appearance defects caused by injection molding, shell The coordination between the shells, the connection between the shells and the structure designed for a certain function... This article will organize and share some basic knowledge related to the structure of the plastic part.
Demoulding angle
The main points of the draft angle
Examples of conventional slopes:
a. The slope of the lower cover boss
b. When the profile line is outside the 87° line, the product profile is not well demolded and requires correction.
c. Demoulding slope around the button
Product wall thickness and uniformity
The molding process and use requirements of plastic parts have important restrictions on the wall thickness of the plastic. Excessive wall thickness of plastic parts will not only increase the cost due to excessive materials, but also bring certain difficulties to the process, such as lengthening Molding time (hardening time or cooling time). It is not good for improving production efficiency. It is easy to produce bubbles, shrinkage holes and dents; if the wall thickness of the plastic part is too small, the flow resistance of the molten plastic in the mold cavity will be large, especially for complex shapes or large plastic parts, and the wall thickness Uniformity, otherwise the molding will shrink unevenly during the molding and cooling process, which will not only cause bubbles, depressions and warping, but also large internal stresses inside the plastic parts. When designing plastic parts, it is required to avoid sharp angles at the junction of uniform wall thickness and thin wall, and the transition is gentle. The thickness should gradually decrease along the direction of plastic flow.
Thickness design example
Thickness of common parts
Issues that should be paid attention to when designing reinforcement
a. In order to ensure the strength and rigidity of the plastic parts without increasing the wall thickness of the plastic parts, the provision of reinforcing ribs on the appropriate parts of the plastic parts can not only avoid the deformation of the plastic parts, but also improve the plastic in some cases. The flow of the molded plastic.
b. In order to increase the strength and rigidity of the plastic parts, it is better to increase the number of ribs instead of increasing its wall thickness.
(1) The relationship between the thickness of the rib and the wall thickness of the plastic part
Example analysis
(2) Examples of rib design
Problems with pillars and holes in the design
(1) The problem of pillars
a. When designing the column, consider whether the glue position will shrink.
b. In order to increase the strength of the pillars, reinforcing ribs can be added around the pillars.
(2) The problem of holes
a. The distance between the hole and the hole should generally be more than 2 times the hole diameter;
b. The distance between the hole and the edge of the plastic part should generally be more than 3 times the hole diameter. If it is limited by the plastic part or used as a fixing hole, the edge of the hole can be reinforced with a boss.
c. The design of the side holes should avoid thin-walled sections, otherwise sharp corners will occur, which will hurt your hands and easily lack materials.
(3) The problem of [Stealing Meat]
Engraving text, symbols and patterns
(1) Among plastic parts, parts exceeding 20g must be added with "material identification"
(2) Engraving on the back of the lower cover
(3) Embossed carving
(4) Intaglio carving
Common card hook design
(1) Usually the upper cover is equipped with a hook for the running slider, and the lower cover is equipped with a hook for the inclined top: because the upper cover has more ribs than the lower cover, and the wall of the upper cover is often deeper than the lower cover, in order to avoid the inclined top Out of space.
(2) Selection of decorative lines for upper and lower covers
(3) The hook should not be too far away from the corner of the machine, otherwise the corner will warp
(4) The hooks should not be too far apart, otherwise it will be easy to sew
(5) OPEN logo off-center part hook design, such as print head cover