Wall thickness Mechanical Design
The size of the plastic material of the basic design code of wall thickness depends on the product to bear force, whether as other parts of the support, to undertake a number of columns, the number of protruding part as well as the selection of plastic materials and. In general, the wall thickness design of thermoplastics should be based on 4mm.
From an economic point of view, too thick products not only increase material costs, lengthen production cycles, but also increase production costs. From the point of view of product design, the excessive product increases the possibility of producing porosity and greatly weakens the rigidity and strength of products.
Mold temperature higher than the melting temperature of plastic material is low, when the plastic material into the mold from the mouth just pumping, due to lower temperature of the mold, the mold surface will form a layer of crystal layer, about 0.2MM, can cause the compound space is very small, need injection pressure is very large, it may cause to fill, there are some thin wall injection molding technology is designed.
The ideal wall thickness distribution is undoubtedly the uniform thickness of the section in any place, but in order to meet the functional requirements, the wall thickness change is always inevitable. In this case, the transition from a thick material to a thin one should be as smooth as possible.
So suddenly the wall thickness transition will lead to unstable size and surface caused by different cooling rates and produce turbulence.
A bar of Mechanical Design
The role of stiffeners is an integral part of the plastic component. Stiffening ribs increase the rigidity and strength of the product without substantially increasing the cross-sectional area of the product. This is especially true for plastic products which are often subjected to stress, torsion, and bending.
In addition, the stiffener acts as an internal runner and cavity filling and plays a major role in helping the plastic flow into the support section of the component.
The design of reinforcement is generally placed on the non-contact surface of plastic products with the extension direction, should follow the product of maximum stress and maximum displacement direction of stiffeners position, also subject to some production considerations such as die cavity filling, shrink and release, etc.
The column of Mechanical Design
1. pillar, which is used for assembling products, separating objects, and supporting other parts, is used for projecting the wall thickness of rubber.
2. hollow pillars can be used to insert parts, tighten screws, etc.
Stop of Mechanical Design
A, stop and reverse stop is closely related to the use of exergy. The action of the check is opposite to the check, and the check is to prevent the outward deformation of the B housing and prevent the A shell from shrinking inward.
B and reverse are made on the shell where the mother stops.
C, the design of the anti-stop opening to the attention of the male buckle from unilateral 8.0MM exergy of at least 6.0MM, because of deformation.
The buckle of Mechanical Design
Design of buckle is generally cannot do without the so-called method of the cantilever; cantilever is based on the characteristics of plastic deformation of the flexure itself, after the return of the original shape of elastic recovery.
The utility model has the advantages that the buckle position provides a product assembly method that is not only simple and fast but also has low cost and high reliability, and the buckle position is easy to assemble and disassemble so as to fully play the idea of assembly by the designer.
Because of a combination of partial buckle position at the same time the production of finished molding, the assembly does not need to cooperate with other parts such as screws, etc. the locked meson assembly process, buckle position is also very simple, generally only need an insert action, without rotation or assembly before the product positioning work, as long as the two sides need a combination of buttons a buckle can cooperate with each other.
Disadvantages: buckle device weakness is a combination of two parts of the buckle, hook-shaped flange part and protruding part after much-repeated use easy to deform because of fatigue effect, buckle bottom connection parts of products breaking, breaking after buckling is difficult to repair, this situation is more common in brittle the incorporation of fiber or plastic materials. Because the buckle and the product simultaneously molding, so buckle damage, that is, product damage.
The remedy is that the buckle device is designed as a plurality of buckles to be shared at the same time, so that the whole device can not operate because of the damage of the individual buckle, thereby increasing the service life of the device. Another weakness of the buckle device is that fastened size tolerance requirements are very strict, inverted position too easy to form buckling damage.
On the contrary, the inverted position is too difficult to control the assembly position, or the combination part appeared to lose the phenomenon.
Stamping of Mechanical Design
A commonly used metal material to the stamping of mechanical design.
1. cold rolled steel plate, cold rolling is in room temperature, the steel plate further rolling thin, as the target thickness of steel plate SPCD, calendering, forming quality, advertising box, learning shell, etc.
2. galvanized steel sheet is coated with zinc on the surface of a cold-rolled plate. Fingerprint resistant corrosion resistance, excellent processability, and maintain common grades of the cold-rolled plate, SECC SECD SECE advantages, from the perspective of cost, SGCC and SECC, will be sent to the factory processing parts electroplating, plating time and save transportation costs.
3. stainless steel, anti atmospheric, acid, alkali, salt, and other media corrosive effects of stainless steel, acid-resistant steel collectively. To achieve the corrosion effect of chromium (Cr) amount of not less than 13% in addition to exergy nickel (Ni) and molybdenum (Mo) to increase the effect.
Because of the variety and content of the alloy, there are many kinds. Stainless steel features, good corrosion resistance, good brightness, high strength, certain flexibility. Common stainless SUS301 exergy spring steel, SUS302 SUS30
Die-casting of Mechanical Design
Reinforcement of die casting, the design requirements of reinforced rib, rib role is to increase the strength and rigidity of die castings, reduce the casting shrinkage deformation, avoid the workpiece ejection from the mold deformation, as the melt filling auxiliary loop, melt flow path.
We should pay attention to the following requirements: exergy
The stiffening ribs of the die castings shall be less than the thickness of the ribs.