Metal stamping parts processing

Metal stamping parts stretching is one of the main stamping processes and is widely used. Various cylindrical, rectangular, stepped, spherical, conical, parabolic and other irregularly shaped thin-walled parts can be made by the stretching process.

1. Flanged hemispherical stretching process: When the spherical member is stretched, the blank is partially in contact with the spherical top of the punch, and the rest is in an unconstrained free state that is suspended. Therefore, the main technical problem of stretching of such spherical parts is the severe thinning of the partial contact portion, or the unstable wrinkling of the curved portion.

2. Edge drawing processing: The flange portion of the pre-processed stretched product is subjected to angular re-stretching processing, and the processing requires the material to have good plasticity.

3. Flange drawing processing: the flange part of the stretched product is processed by shallow drawing. Its stress-strain condition is similar to compression flanges. Due to the tangential compression stress, it is easy to wrinkle, so the forming limit is mainly limited by compression wrinkles.

4. Deep drawing processing: The stretching processing product exceeding the limit of drawing processing can be completed after two times of stretching. Products that have been stretched in the depth direction of the front station are re-stretched in the depth direction. The wide flange tensile member is stretched to the desired flange diameter upon first stretching, and the flange diameter remains unchanged after subsequent stretching.

5. Conical stretching processing: deep conical parts with h/d>0.8 and α=10°~30°. Due to the large depth, the degree of deformation of the blank is large, and only the local area of the contact between the blank and the punch is transmitted. The forming force is very likely to cause local over-thinning and even rupture of the blank, which needs to be gradually formed through multiple transitions. The step stretching method firstly stretches the billet into a stepped transition piece whose stepped shape is tangent to the inner shape of the tapered portion and finally expands to form a taper. The number of times of stretching, the process, etc. of the step transition metal stamping parts are the same as those of the stepped cylinder parts.
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