Press Brake

8 Quick Tips For Bending Process

CNC press brake

General principles of press brake machine bending

  1. The section of the bending part will change in the bending deformation zone. The smaller the ratio of the bending radius to the back of the plate, the greater the change in the section shape
  2. The bending line of the bent part should be perpendicular to the direction of the tie pattern, and it is best to use the smooth surface of the blank as the outer surface of the bent part to reduce the outer layer cracking

3.Springback will occur during bending and forming. The larger the ratio of the bending radius to the plate thickness, the greater the springback.

Selection of bending radius

The bending radius of the bending parts need to select appropriately, not too large or too small. The minimum bending radius should only be selected when the structure is necessary.

Process requirements

  1. The length, width and thickness of the material, and the direction of the material grain should meet the requirements of the drawing; the surface of the plate should be clean.
  2. Choose suitable molds according to the drawing requirements and materials.
  3. Check the working condition of the bending machine and maintain the equipment before processing.

4.Before and during processing, the bending surface of the mold should be cleaned and lubricated.

Process quality

4.1.1 The non-processed surface should keep clean. If the raw material has a surface protective film, it need to retain if it does not affect the processing realization or the accuracy of the part; the surface scratch shall not exceed the requirements for heavier scratches, and the export products shall not exceed the light Degree of scratching.

4.1.2 Surface indentation, that is, periodic or non-periodic concave impressions on the surface of the sheet metal, according to the length of the processed sheet metal material ≯ 5×10/m.

4.1.3 The curved surface shall not have obvious tensile cracks.

4.1.4 There shall be no cracks on the edges of the bending corners. When there is unavoidable bending and cracked edges, should open appropriate size process holes at the cracked edges.


5.1 The linear dimensions and tolerances of the structural parts and the relative positions of the openings and slots should meet the requirements of the drawings, and the unmarked tolerances should meet the requirements of tolerance class m.

5.2 The diagonal dimension shall meet the requirements of linear dimension, shape position dimension or tolerance requirements:

a. When the diagonal length is less than or equal to 550 mm, the difference between the diagonals shall not exceed 1.5 mm;

b. The length of the diagonal line is more than 550 mm, and the difference between the diagonal lines is not more than 3 mm.


6.1 Straightness, flatness, and squareness can not mark with tolerance level L requirements. .

6.2 The unmarked tolerance value of parallelism is equal to the given dimensional tolerance value, or the corresponding tolerance value of the unmarked tolerance value of straightness and flatness, whichever is greater.

6.3 Other requirements need to give by drawings or process documents.


7.1 The first piece inspection need to carry out before processing multiple sheet metal bending parts.

7.2 The appearance inspection shall be in accordance with the requirements of 4.1.

7.3 The size inspection of bending parts shall be in accordance with 4.2.

7.4 The shape inspection of the bending parts shall be in accordance with the requirements of 4.3.

7.5 The bent parts that have been reworked and repaired shall be re-inspected according to the inspection procedures, and the quality index shall not be reduced.

7.6 Other quality requirements shall be inspected and judged under the provisions of drawings and process documents.


8.1 Should try to avoid bending with eccentric load.

8.2 The bending force of the workpiece shall not be greater than the nominal force.

8.4 The opening size of the V-shaped slot of the lower die of the bending workpiece should be greater than 6-8 times the thickness of the sheet.

8.5 The operator needs to wear protective gloves during operation.

8.6 The gap between the upper and lower molds of the bending machine must be adjusted evenly, and the gap can be 1mm larger than the plate thickness.

8.7 It is not allowed to place tools, measuring instruments, etc. on the mold of the bending machine and the workpiece table.

8.8 The processed parts should be handled and put gently to avoid dragging and throwing away; the maximum stacking height on site should not exceed 1m.

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