The bending and forming of the sheet metal is the sheet metal processing performed on the bending machine.
The sheet to be formed is placed on the CNC press brake, the upper mold is lifted by the oil cylinder, the slider is slid to the appropriate position, and then the upper mold is lowered to the desired position. On the formed sheet, the metal is bent and formed by applying force to the bending lever on the bending machine.
As people have higher and higher requirements for the accuracy of bending sheets, most factories have begun to choose CNC press brake instead of hydraulic bending machines.
Because the CNC press brake has fast speed, high precision, more convenient operation, and more in line with modern requirements.
In the bending process, we usually can use the following bending methods
Point contact bending
As shown in the figure, by using points A, B, and C to make the material and the mold contact and bend, point contact bending is called a typical floating bending, the reason is that it is not completely pressed to the bottom, in the state of contact with air Make a bend.
The characteristic of this bending is that the bending angle can be processed freely. For example, using a 30° mold for bending, it can process any angle between 180° and 30°. The most suitable V-width for point contact bending is 12-15 times the plate thickness.
Ordinary bending is also called close bending, and the English for close bending is bottom. The term “press to the bottom” and “bottom contact” are commonly used in workshop terms, and they are widely used because they can obtain better bending accuracy with less pressure.
The etymology of shear bending is (coin), which means “coin manufacturing” is a very precise processing method. The purpose of shearing and bending is to obtain good accuracy, extremely small internal R, and 5-8 times the TON required for ordinary bending.
The problem of shear bending
・Because of the higher pressure, larger bending equipment is also required.
・The mold wears out quickly.
・There are also restrictions on molds. (Use a larger pressure-resistant mold)
Sometimes other bending forms are also used, usually the following
L folds are divided into 90° folds and non-90° folds according to the angle, and their naming is based on the inner angle after completion. The deformation coefficient of 90° bending is 0.4 times the material thickness
When N-fold forming, different processing methods are adopted according to the size values of Length and height. One is directly divided into two-fold forming, and the other is to add gaskets to reverse folding and flattening. Generally, the H in N-fold is more Important size.
Z-folding is also called break difference. According to the forming angle, it is divided into straight edge break and hypotenuse break.
The processing method is based on the break height. The straight edge break is used when the break height h is less than 3.5 times the material thickness. Differential mold or easy mold forming, when the thickness of the material is greater than 3.5 times, the normal one positive and one reverse two folds are used.
The hypotenuse break When the length of the hypotenuse l is less than 3.5 times the material thickness, the differential mold or easy mold is used for forming, greater than 3.5 times When the material is thick, use the normal one positive one reverse two folds to complete
Dead edge bend
The dead edge is also called reflex flattening. Its forming process is completed in two steps: first bend to about 35 degrees, this step is the insertion depth, and then use the flattening die to press out the dead edge. Pay attention to the parallelism of the large surface after forming. degree.