The selection of the press brake model is mainly considered from the following factors:
Workpiece: The first important item worth considering is the part you want to produce. The point is to buy a 200T Press Brake machine that can complete the processing task with the shortest worktable and the smallest tonnage. Carefully consider the material grade and the maximum processing thickness and length. If it is large Part of the work is low carbon steel with a thickness of 2mm and a maximum length of 2m, so the free bending force does not need to be greater than 40 tons. However, if you are engaged in a large number of bottomed concave mold forming molds, you may want to consider a machine tool of about 125 tons. Most of the workpieces are 1 meter or shorter, and the tonnage is almost halved, which greatly reduces the purchase cost.
Deflection: You should also consider the possible deflection of this machine. Under the same load, the deflection of the 4m machine table and slider is 4 times that of the 2m machine. That is to say, the shorter machine needs more With fewer gasket adjustments, qualified parts can be produced. Reduce gasket adjustments and shorten preparation time.
Material grade is also a key factor. Compared with mild steel, the load required for stainless steel is usually increased by about 50%, while most grades of soft aluminum are reduced by about 50%. You can always get the tonnage of the E300 Press Brake from the press brake manufacturer. Table, the table shows the estimated tonnage required per foot of length under different thicknesses and different materials.
The bending radius of the part: When using free bending, the bending radius is 0.156 times the opening distance of the die. During the free bending process, the opening distance of the die should be 8 times the thickness of the metal material. If the bending radius is almost as small as the material thickness, it must be The bottomed die is formed. However, the pressure required for bottomed die molding is about 4 times greater than free bending.
If the bending radius is less than the thickness of the material, a punch with a front-end fillet radius smaller than the thickness of the material must be used, and the imprint bending method must be used. In this way, 10 times the pressure of free bending is required.
In terms of free bending, the punch and die are processed at 85° or less than 85°. When using this set of molds, pay attention to the gap between the punch and the die at the bottom of the stroke, and it is sufficient to compensate for the springback and keep the material at about 90° The excessive bending.
Generally, the springback angle of the free bending die on the new press brake is ≤2°, and the bending radius is equal to 0.156 times the opening distance of the die.
For bottomed die bending, the die angle is generally 86 ~ 90°. At the bottom of the stroke, there should be a gap slightly larger than the thickness of the material between the male and female dies. The forming angle is improved because of the tonnage of the bottomed die. Larger (about 4 times of free bending), which reduces the stress that usually causes springback in the bending radius.
The imprint bending is the same as the bending of the bottom die, except that the front end of the punch is processed to the required bending radius, and the gap between the punch and the die at the bottom of the stroke is less than the thickness of the material. Due to the application of sufficient pressure (about 10 times that of free bending) ) Forcing the front end of the punch to contact the material, basically avoiding springback.
In order to choose the lowest tonnage specification for WC67K Press Brake, it is best to plan for a bending radius larger than the material thickness, 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 part and its future use.
Accuracy: Bending accuracy is a factor that needs to be carefully considered. It is this factor that determines whether you need to consider a CNC press brake or a manual press brake. If the bending accuracy requires ±1° and it cannot be changed, you must pay attention On CNC machine.
The repeatability of the slider of the electro-hydraulic synchronous CNC press brake is ±0.01mm, and the precise angle of forming must use such accuracy and a good mold. The repeatability of the slider of the manual press brake is ±0.002 inches, and the appropriate mold is used Generally, a deviation of ±1° will be generated under the conditions of the mold. In addition, the CNC press brake is ready for rapid mold assembly. When you need to bend many small batches of parts, this is an indisputable reason for consideration. Mold: Even if you have With racks of molds, don't think that these molds are suitable for newly purchased machines. The wear of each mold must be checked by measuring the length from the front end of the punch to the shoulder and the length between the shoulder of the concave mold.
press brake model introduction:
WC67Y series, WC67K series, WE67K series.
W —— Code of hydraulic press brake
A The workbench moves upward. This kind of 200T Press Brake is more common in old-fashioned imported machines, and its synchronization is poor, and it is rare in the market now.
B Parallel cylinders are hydraulically synchronized, most of which are single-cylinder machines. They are connected by hinges. Now they are rarely used for small tonnage press brakes.
C Torsion axis synchronous WC67K press brake. Now widely used synchronous mechanism. Its synchronization is better and can meet a small amount of unbalanced load. Now manufacturers adopt this method. Torsion axis synchronization is also divided into two models, according to the sliding The positioning method of the block stroke is distinguished. One is the built-in cylinder, and the other is the independent turbine and worm positioning. The configuration is higher. It is a new design and easy to maintain.
D Machine-hydraulic synchronization, through the mechanical transmission to control the oil intake of the cylinder, so as to achieve the synchronization of the two cylinders. Mostly used for E300 Press Brakes with a processing width of 6 meters or more.
E Electro-hydraulic synchronization, the signal is transmitted to the computer through the grating ruler. The computer is analyzed and then sent to the electro-hydraulic servo proportional valve, which controls the movement of the slider, and the grating on the slider detects the signal to compensate, forming a closed loop, and its positioning accuracy is very high .
K computer control. Divided into a variety of control systems. Economical CNC and high-precision CNC. Economical CNC is mostly used for torsion axis synchronous press brakes to realize automatic control of backgauge and slider stroke adjustment.