Views: 7 Author: DURMAPRESS Publish Time: 2022-12-16 Origin: DURMAPRESS
There are a variety of ways for WE67K- 135T3200 CNC bending machine to bend the plate, and there are many classification ways for different principles. In this paper, from the different relative positions of the upper and lower molds during bending processing and the different shapes of folding, several common bending methods are introduced in detail, and the bending process and precautions are described in detail.
1. Relative position of the mold: clearance bending and bottom bending
Firstly, according to the different relative positions of the upper and lower molds during bending processing, the bending processing is divided into two forms: clearance bending and bottom bending. The characteristics and differences of the two are as follows:
l Clearance bending
CNC bending machine in the bending process between the upper die and the lower die is not pressed, by adjusting the upper die into the lower die opening depth to get the required bending Angle, this bending method is called gap bending.
The deeper the upper die enters the lower die, the smaller the bending Angle; The greater the vice versa. Due to the elasticity of the material, it is also necessary to consider excessive bending to control the amount of springback.
The advantage of gap bending is that a small number of molds can be used to achieve a variety of Angle forming processing, and the required processing pressure is small. In general, to obtain the best bending effect, the ratio of the thickness of the material B to the width of the V-shaped opening of the lower die V can be selected as follows:
(1) When the material thickness is below 12.7mm, B: V is 1:8;
(2) When the material thickness is 12.7~22.2mm, B: V is 1:10;
(3) When the material thickness is above 22.2mm, B: V is 1:12.
The above three ratios are standard die ratios, which are made of low carbon steel with a material strength of 43.4kg/mm2. In the preparation of bending processing program, the above parameters can be set in the numerical control system, the system automatically processed after the generation of processing program.
l Bottom bending
Numerical control bending machine adopts bottom bending when the plate is pressed between the upper and lower die, so as to obtain the required bending Angle and elbow radius. CNC bending machine is suitable for mass and mass production in the enterprise, processing thickness of the metal sheet below 2mm.
The bending radius is small, the bending precision is high, and the precision is good. It should be noted that the working pressure of bottom bending is greater than the working pressure of gap bending, generally more than three times.
The Angle of the bottom bending die should be adapted to the plate Angle and material. Usually in the bottom bending of low carbon steel, the Angle of the upper and lower die should be consistent with the required Angle of the plate. When the bottom bending method is used, the mold ratio, that is, the ratio between the thickness of the sheet material B and the opening distance of the lower die V, is B: V= 1:6.
During the bending process, the force between the upper and lower die is applied to the material, resulting in plastic deformation of the material. Working tonnage refers to the bending pressure during bending. The influencing factors to determine the working tonnage are: bending radius, bending mode, mold ratio, elbow length, bending material thickness and strength, etc.
2. Fold different shapes: L fold, N fold, Z fold, backfold flatten, press hardware
According to the different shapes formed after bending processing, the bending processing is divided into L folding, N folding, Z folding, folding flat, pressing hardware and other forms, its characteristics and differences are as follows:
l L fold
It's split into 90˚ and non-90 ˚ angles. According to processing, general processing (L> V/2) and special processing (L
1) The mold is selected according to the material, plate thickness and forming Angle.
2) The principle of standing:
(1) To two after the positioning principle, and to the shape of the workpiece positioning.
(2) When a post-fixed alignment, pay attention to the deflection, and the bending size of the workpiece in the same center online.
(3) When small folding and bending, the reverse position processing is the best.
④ It is better to set the rule back and lower in the middle. (It is not easy to tilt when leaning back)
⑤ The edge of the seat is close to the standard after the best.
⑥ To the long side of the position is better.
⑦ With a fixture to assist the rest (hypotenuse irregular rest).
3) Precautions: Attention should be paid to the positioning mode during processing and the post-fixed movement mode in various positioning processing modes. When the mold is formally installed, it should be pulled behind to prevent the deformation of the workpiece when bending. When the workpiece is bent internally, the shape of the workpiece is larger, and the bending area is smaller, so that the tool and the bending area are difficult to coincide, resulting in difficult positioning of the workpiece, or damage to the bending workpiece. In order to avoid the above situation, a certain point can be added in the longitudinal direction of processing, so that the two directions of positioning processing, convenient processing positioning, and improve processing safety, avoid workpiece damage, improve production efficiency.
l N fold
N fold according to the shape of different processing methods. When bending, the material size should be greater than 4mm and the size of X size is limited by the mold shape. If the size of the material is less than 4mm, special processing methods are used.
1) According to the thickness of the material, size, material and bending Angle to select the mold.
2) Alignment principle: ensure that the workpiece does not interfere with the tool
① Ensure that the resting Angle is slightly less than 90 degrees.
② It is better to use two back to set the position, except for special circumstances.
① After bending L, the Angle should be ensured at 90 degrees or slightly less than 90 degrees to facilitate processing.
(2) When the second fold is processed, the positioning position is required to be centered on the processing surface.
l Z fold
The Z fold is also called the segment difference, that is, one plus one minus one. The hypotenuse and the straight edge are divided according to the Angle. The minimum size of bending is limited by the machining mold, and the maximum size is determined by the shape of the machining machine. Under normal circumstances, when the inner size of Z fold is less than 3.5T, section differential die processing is used. When it is larger than 3.5T, the normal processing method is adopted.
1) The principle of standing:
① Convenient position, good stability.
② The general supposition is the same as the L fold.
The second alignment is required to process the workpiece and the lower die flat.
① The processing Angle of L fold must be in place, generally required in 89.5~90 degrees.
After the rule to pull after, pay attention to the deformation of the workpiece.
③ The sequence of processing must be correct.
(4) For special processing, can be processed by the following methods: center line separation method (eccentric processing), small V processing (need to increase the bending coefficient), easy forming, repair grinding die.
l Folding and flattening
Backfolding flattening is also known as dead edge. The processing steps of dead edge are as follows: bending and inserting deep to about 35 degrees, and then pressing and molding to flat and tight.
1) Mode of mold selection: select the V slot width of the lower mold with insertion depth of 30 degrees according to 5--6 times the material thickness, and select the upper mold according to the specific situation of the dead edge processing.
2) Precautions: Pay attention to the parallelism of both sides of the dead edge. When the processing size of the dead edge is long, the flattened edge can be folded a warping Angle before flattening. For short dead edges, padding can be used.
l Press hardware
The use of folding bed pressing and assembling hardware, generally use the concave die, fixture and other auxiliary mold processing. Generally there are: pressure nuts, pressure studs, pressure screws and some other hardware.
Points to note:
(1) When the workpiece shape needs to be avoided, it should be avoided.
(2) After processing to detect torque, thrust to meet the standard and hardware and workpiece is flat and close.
③ After bending and pressing the sockets, when pressing next to the machine tool, attention should be paid to the parallelism of processing and mold.
(4) If it is swollen, but also pay attention to the expansion of the sockets can not have cracks, swelling edge can not be higher than the surface of the workpiece. Author: wuxi god rushed forging https://www.bilibili.com/read/cv17308304 reference: bilibili