Views: 19 Author: Durmapress Publish Time: 2020-06-08 Origin: Durmapress
1. Hydraulic Press Brake Workpiece and tonnage
The first important thing worth considering is the parts you want to produce. The point is to buy a CNC Press Brake that can complete the processing task with the shortest work table and the smallest tonnage.
Carefully consider the material grade and maximum processing thickness and length. If most of the work is low carbon steel with a thickness of 16 gauge and a maximum length of 10 feet, the free bending force need not be greater than 50 tons. However, if you are engaged in a large number of bottomed die forming, maybe you should
Consider a 150-ton CNC Hydraulic Press Brake.
Assuming that the thickest material is 1/4 inch, 10 feet of free bending requires 165 tons, and bottomed die bending (correction bending) requires at least 600 tons. If most of the work pieces are 5 feet or less-the tonnage is almost halved, which greatly reduces the purchase cost. zero
Piece length is very important to determine the specifications of the new Stainless steel Bending Machine.
Under the same load, the deflection of the 10-foot machine table and slider is four times that of the 5-foot machine. This means that shorter machines require fewer shim adjustments to produce qualified parts. Reducing shim adjustments also shortens preparation time. Material grades are also
A key factor. Compared with low carbon steel, the load required for stainless steel is usually increased by about 50%, while the soft aluminum of most brands is reduced by about 50%. You can get the tonnage table of the machine from the Steel bending machine manufacturer at any time, the table shows
Estimated tonnage required in feet.
3. Bending radius of parts
When using free bending for the CNC Press Brake Machine , the bending radius is 0.156 times the opening distance of the die. In the free bending process, the opening distance of the die should be 8 times the thickness of the metal material. For example, when forming a 16 gauge mild steel with a 1/2 inch opening distance, the bending radius of the part is about 0.078
inch. If the bending radius is almost as small as the thickness of the material, the bottomed die must be formed. However, the pressure required to form the bottomed die is about 4 times greater than free bending.
If the bending radius is smaller than the thickness of the material, a punch with a radius at the front end smaller than the thickness of the material must be used, and resort to the imprint bending method. In this way, it requires 10 times the pressure of free bending.
As far as free bending is concerned, the punch and die are processed at 85° or less (smaller is better). When using this set of molds, pay attention to the gap between the punch and the concave mold at the bottom of the stroke, and enough to compensate for the springback and keep the material bent excessively about 90°.
Generally, the springback angle of a free bending die on a new bending machine is ≤2°, and the bending radius is equal to 0.156 times the opening distance of the die.
For bottomed concave mold bending, the mold angle is generally 86~90°. At the bottom of the stroke, there should be a gap between the male and female dies slightly larger than the thickness of the material. The forming angle is improved, because the tonnage of the bottomed die bending is larger (about 4 times of free bending), reducing
Reducing the stress that normally causes springback within the bending radius.
The embossing bending is the same as that of the bottomed concave mold, except that the front end of the punch is processed to the required bending radius, and the gap between the convex and concave molds at the bottom of the stroke is less than the material thickness. Due to the application of sufficient pressure (about 10 times of free bending) the front end of the punch is forced to contact
Material, basically avoid rebound.
In order to select the lowest tonnage specification for press break , it is best to plan for a bending radius greater than the thickness of the material, and use the free bending method as much as possible. When the bending radius is large, it often does not affect the quality of the finished part and its future use.