Optimization Measures for Wrinkling and Bulging
Set a high-pressure edge ring and increase the edge holding force. In the forming process, the main factor for wrinkling and bulging is insufficient edge holding force, so using an edge holding ring or increasing the edge holding force can effectively reduce forming defects. After adding the edge holding ring, the sheet is constrained to flow in the gap between the edge holding ring and the concave shape, and the stability is improved, so that deeper drawing can be performed and cracks are not easily formed. At the same time, the use of a double-action press can also reasonably adjust the edge holding force, thereby reducing bulging defects.http://www.samhotool.com
Optimized Solution to Avoid Cracking
The main cause of the fracture is that the design of the 0.5 diameter range of the punch corner and the setting of the distance between the punch and the concave are unreasonable.
If the radius of the punch corner r is too small, the blank size will form a large distortion at the corner, and it is easy to break at the dangerous section. If the outer convex area is large, at the beginning of the drawing, due to the increase in the suspended volume of the blank under the punch, the contact volume with the mold parts is also reduced, which is more likely to cause large-size wrinkles in the blank. Therefore, according to actual experience, 8 to 15 times the sheet thickness is usually selected as the 0.5 diameter range of the punch corner design, which can effectively suppress the cracking problem.
The distance between the convex and concave refers to the tolerance of the lateral width of the convex and concave. When the distance between the convex and concave is too large, the forming quality of the parts is better, but due to the excessive drawing force, the parts are easy to break. When the gap between the convex and concave is too large, due to the small drawing capacity, the parts are more likely to form surface wrinkles, excessive material thickness, and uneven side walls. The appropriate size of the convex and concave gap helps to control the friction of the drawing process and improve the fluidity of the material. Therefore, it is usually more appropriate to choose a mold part gap size that is ten percent smaller than the blank thickness.
Optimization Measures for Contour Tolerance
In the stainless steel forming process, contour rate tolerance is a difficult problem to overcome. There is currently a lack of effective methods to control it, but it can be optimized through corresponding methods. There are usually two ways to adjust the rebound to achieve contour optimization. One way is to expand the vertical deformation range of the mold and increase the drawing amount. Thereby expanding the plastic deformation range of the stainless steel blank contour, and obtaining a spherical contour with better effect in the center. However, this method is easy to cause the real wood board to break and the material efficiency is low. The other way is to further optimize the contour by adjusting the ball diameter tolerance of the punch.
Based on the design characteristics of the bridge bearing and the actual installation method, the contour can be adjusted by controlling the punch accuracy. Since the spherical bearing adopts a convex surface, the punch ball diameter can be set to negative accuracy. When forming the cut edge, the material rebound ball diameter is within the design working area, thus meeting the design conditions. The main application surface of the friction pendulum anchor is the die, and the area ball diameter of the punch can be set to negative tolerance accuracy, so that it is more in line with the design conditions than the ball diameter during the forming rebound. However, this technology currently lacks accurate tolerance measurement and needs to undergo cumulative testing and multiple mold modifications before correction.
Optimization Solutions to Improve Surface Quality
The surface quality of the punch is improved by grinding the punch, coating the punch with an anti-corrosion layer, and storing it in a sealed manner after use. The surface defects of the stainless acid-resistant steel plate in the die after forming are reduced. In addition, the lubrication system is also the most effective way to improve the forming quality of stainless steel.
During the forming process, a large friction will be formed inside the blank size and the concave surface, and between the blank size and the pressure ring. Not only will it reduce the allowable and variable degree of deep drawing, but it will even cause surface wear of the parts. Therefore, lubricating oil is evenly applied to the concave surface, the surface where the pressure ring and the blank size are in contact, and the surface of the blank size where the concave and the pressure ring are in contact. And ensure that the lubricated parts are clean before starting the processing and forming.
However, do not apply lubricating oil to the surface of the punch and the surface of the blank size that is in direct contact with the punch. Because the lubricant weakens the ability of the blank size and the punch surface to transmit the changing force through friction, forming defects are generated. The optimization measures for different defects are also very different. In engineering use, it is necessary to adjust according to the actual conditions and reduce the formation of forming defects through coordination in various ways.
