1. Influence of in-plane opposite sex on formability of sheet metal
Relative to the plate rolling in different directions on the performance is different, so that the deformation of cylindrical forming parts is not axisymmetric, forming parts appeared on the lug.The appearance of lug not only makes the shape of the formed part not conform to the requirements (belonging to the category of conformal), but also disadvantageous to the allowable deformation degree.
Obviously, the appearance of the lug on the cylindrical forming part will inevitably make the contraction deformation in the direction of the cylinder uneven distribution on the cylinder.This wrinkling or cracking could have been avoided if the deformation had been evenly distributed, or at least would have occurred with larger deformation.
The effect of lug on deformation cost and profit can be expressed in lug direction as well as in concave valley.The form is located in the lug direction, the die at the four corners of the material will appear tensile crack.This is due to the lug part of the wool protruding line width, further deformation needs to apply the force must be larger, when it is large to a certain extent, the maximum stress - die round corner will pull crack.
Of course, for non-axisymmetric parts, according to the specific situation of the parts, the appropriate selection of blanking azimuth, the use of in-plane properties of the opposite sex, it will become a favorable factor, sometimes can improve the allowable deformation degree.
The influence of the inplane property on the conformal property is also shown in the bending parts.Because of the in-plane property of the material, that is, the direction of the principal strain is not always in line with the direction of the principal stress, the bending line is not a rolling or transverse alignment with the plate bending, there appears to be an intuitive distortion that does not seem to occur.
The negative effect of the titanium plate is more obvious, especially in the aspect of formability.Because the performance of different directions is different, even if the forming has the same stress, different springback will be produced during the cutting, which causes the shape distortion of the formed parts, and even the original plane will warp.
2. Influence of surface anisotropy on plate formability
As mentioned above, the surface of the opposite sex is typical of the force plate is no longer flat and the curvature.Obviously, the proper placement of wool in the forming, so that the forming curvature and due to the surface of the curvature generated by the opposite sex, will be conducive to the forming of parts, improve the allowable deformation degree;Otherwise, the allowable deformation degree will be reduced.For example, 1.5mm thick TCIM material has obvious surface anisotropy. When flanging a round hole, if the side with a slightly larger anisotropy index is the inner surface of the flanging part, the limiting flanging coefficient is 2.8% larger than when it is on the outer surface.
Due to the undesirable curvature change of the surface opposite sex, it has a bad influence on the conformal and formability in general.