Application of high-precision CNC bending machine in the elevator industry: the elevator car is mainly composed of three sets of door panel panel (front wall - control wall - door light beam - ceiling decoration top and other components. The material is generally made of 1.0 ~ 2.0mm stainless steel plate or cold rolled carbon steel plate. The processing process route is generally cut by shearing machine and then punched by punching machine or directly punched by laser cutting material, and finally bending forming.
High precision CNC bending machine
In the bending process to ensure the quality of products, it is necessary to set the minimum bending radius, the minimum bending straight edge, the minimum hole edge distance and other extreme values. Different plates have different minimum bending radius due to their different elongation. In the commonly used sheet metal, the minimum bending radius is shown in Table 1, where t is the thickness of sheet metal.
Minimum bending straight edge refers to the distance from the edge of the plate to the bending edge. If the length is too small, it may lead to bending deformation and even the risk of mold damage. The distance is generally h > 2 t.
Hole margin means that in the process route of punching before bending, if the position of the hole is in the bending deformation zone, the hole will be deformed when bending. When t ≤ 2mm, hole margin S ≥ T + R; When t ≥ 2mm, hole margin S ≥ 1.5t+r.
press brake cnc bending sequence is:
When making the bending process route, the bending sequence is also a key content. Improper bending sequence may lead to large deviation of forming size of parts, and even interference will lead to failure to complete bending.
Bending process generally follow the following four basic principles: (1) from inside to outside bending; (2) from small to large bending; (3) Bend the special shape first, then bend the general shape; (4) The former process does not affect or interfere with the subsequent process after forming. For example, when bending the control wall, the bending principle follows from the inside to the outside, and the bending sequence is shown in Figure 3.
High precision numerical control bending machine bending common problems and solutions
When potential problems are found in the bending process, they should be optimized and solved in time. In the elevator car bending process, there are mainly the following aspects of the problem.
The forming size does not agree with the drawing
The forming size of the workpiece is not consistent with the drawing because of three aspects: the size error of the opening material, the incorrect bending position and the accumulated error of multiple bending. The solution measures are: adjust the bending coefficient, recalculate the expansion size; Adjust positioning; Select reasonable positioning datum to eliminate cumulative errors. If the opening size error and the cumulative bending error are within the allowable range, the forming size can be guaranteed first, and the error will be accumulated to the non-assembly edge that has no influence on the workpiece.
Numerical control bending machine bending Angle deviation problem
The bending Angle of the workpiece is too large or too small easy to cause the bending Angle deviation, the main reason is that the lower die V mouth is not suitable, the die rebound compensation parameter is set improperly and the bending machine pressure does not match. The solution is: refer to the bending mold table to select the appropriate lower die, adjust the rebound compensation value and the bending machine pressure.
CNC bending machine bending edge crack problem
The main reasons for the crack in the bending edge include too small bending radius, plate grain parallel to the bending line, the burr of the blank outwards, and poor material plasticity. The solution measures are: increase the bending radius to use high-precision CNC bending machine or gouging processing; Change the direction of the workpiece opening layout; Change the direction of the burr and place it on the inner fillet of the workpiece; Replace the material with good plasticity.