When bending and flattening sheet metal, PROE automatically calculates the length of the material. The calculation formula is as follows:
L=0.5π×(R+K coefficient× t )× (θ/90)
L: expanded length of sheet metal.
R: the inner diameter of the elbow.
T: material thickness
θ: bending angle
Y coefficient: a constant determined by the position of the nerve bending line, with a default value of 0.5 (so-called "bending line"). The default value of the initial bending factor can be set in the configuration.
In the practice of sheet metal design, the commonly used flattening formula of sheet metal is based on k coefficient, and the value range is 0 ~ 1, which indicates the resistance of material to stretching when bending. The relationship with y coefficient is as follows
Y coefficient =(π/2)×k coefficient
There are many sheet metal materials suitable for stamping. The sheet metal materials widely used in the electronic and electrical industry are:
1. Ordinary cold-rolled plate? SPCC SPCC refers to the continuous rolling of steel ingots into coils or steel plates with required thickness by cold rolling mill. The surface of SPCC is unprotected, and it is easy to be oxidized when exposed to air, especially in humid environment, the oxidation speed is accelerated and dark red rust appears. When in use, the surface should be painted, electroplated or otherwise protected.
⒉? The base material of galvanized steel sheet SECC SECC is common cold-rolled steel coil, which becomes galvanized products after degreasing, pickling, electroplating and various post-treatment processes on the continuous galvanizing production line. SECC not only has the mechanical properties and approximate machinability of common cold-rolled steel plates, but also has excellent corrosion resistance and decorative appearance. It has great competitiveness and substitution in the markets of electronic products, household appliances and furniture. For example, SECC is widely used in computer chassis.
13. hot-dip galvanized steel sheet SGCC hot-dip galvanized steel coil refers to semi-finished products after hot rolling, pickling or cold rolling, which are washed, annealed and immersed in molten zinc bath at a temperature of about 460℃ to coat the steel sheet with zinc, and then tempered, leveled and chemically treated. SGCC material is harder than SECC material, with poor ductility (avoiding deep drawing design), thicker zinc layer and poor weldability.
3. The stainless steel SUS30 1 Cr (Cr) content is lower than that of SUS304, and its corrosion resistance is poor. But after cold working, it can obtain good tensile strength and hardness and good elasticity, which is mostly used for leaf springs and EMI prevention.
5. Stainless steel SUS304 is one of the most widely used stainless steels. Because it contains Ni (nickel), it has better corrosion resistance and heat resistance than steel containing Cr (chromium). It has excellent mechanical properties, no heat treatment hardening and no elasticity.